Move some system services to separate directories

Refactored the directory structure so that services can be optionally
excluded. This is step 1. Will be followed by another change that makes
it possible to remove services from the build.

Change-Id: Ideacedfd34b5e213217ad3ff4ebb21c4a8e73f85

19 files changed, 4684 insertions, 0 deletions

diff --git a/libs/common_time/Android.mk b/libs/common_time/Android.mk
new file mode 100644
index 0000000..75eb528
--- /dev/null
+++ b/libs/common_time/Android.mk
@@ -0,0 +1,36 @@
+LOCAL_PATH:= $(call my-dir)
+
+#
+# common_time_service
+#
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    common_clock_service.cpp \
+    common_time_config_service.cpp \
+    common_time_server.cpp \
+    common_time_server_api.cpp \
+    common_time_server_packets.cpp \
+    clock_recovery.cpp \
+    common_clock.cpp \
+    main.cpp \
+    utils.cpp
+
+# Uncomment to enable vesbose logging and debug service.
+#TIME_SERVICE_DEBUG=true
+ifeq ($(TIME_SERVICE_DEBUG), true)
+LOCAL_SRC_FILES += diag_thread.cpp
+LOCAL_CFLAGS += -DTIME_SERVICE_DEBUG
+endif
+
+LOCAL_SHARED_LIBRARIES := \
+    libbinder \
+    libcommon_time_client \
+    libutils \
+    liblog
+
+LOCAL_MODULE_TAGS := optional
+LOCAL_MODULE := common_time
+
+include $(BUILD_EXECUTABLE)
diff --git a/libs/common_time/clock_recovery.cpp b/libs/common_time/clock_recovery.cpp
new file mode 100644
index 0000000..3a7c70c
--- /dev/null
+++ b/libs/common_time/clock_recovery.cpp
@@ -0,0 +1,423 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * A service that exchanges time synchronization information between
+ * a master that defines a timeline and clients that follow the timeline.
+ */
+
+#define __STDC_LIMIT_MACROS
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+#include <stdint.h>
+
+#include <common_time/local_clock.h>
+#include <assert.h>
+
+#include "clock_recovery.h"
+#include "common_clock.h"
+#ifdef TIME_SERVICE_DEBUG
+#include "diag_thread.h"
+#endif
+
+// Define log macro so we can make LOGV into LOGE when we are exclusively
+// debugging this code.
+#ifdef TIME_SERVICE_DEBUG
+#define LOG_TS ALOGE
+#else
+#define LOG_TS ALOGV
+#endif
+
+namespace android {
+
+ClockRecoveryLoop::ClockRecoveryLoop(LocalClock* local_clock,
+                                     CommonClock* common_clock) {
+    assert(NULL != local_clock);
+    assert(NULL != common_clock);
+
+    local_clock_  = local_clock;
+    common_clock_ = common_clock;
+
+    local_clock_can_slew_ = local_clock_->initCheck() &&
+                           (local_clock_->setLocalSlew(0) == OK);
+    tgt_correction_ = 0;
+    cur_correction_ = 0;
+
+    // Precompute the max rate at which we are allowed to change the VCXO
+    // control.
+    uint64_t N = 0x10000ull * 1000ull;
+    uint64_t D = local_clock_->getLocalFreq() * kMinFullRangeSlewChange_mSec;
+    LinearTransform::reduce(&N, &D);
+    while ((N > INT32_MAX) || (D > UINT32_MAX)) {
+        N >>= 1;
+        D >>= 1;
+        LinearTransform::reduce(&N, &D);
+    }
+    time_to_cur_slew_.a_to_b_numer = static_cast<int32_t>(N);
+    time_to_cur_slew_.a_to_b_denom = static_cast<uint32_t>(D);
+
+    reset(true, true);
+
+#ifdef TIME_SERVICE_DEBUG
+    diag_thread_ = new DiagThread(common_clock_, local_clock_);
+    if (diag_thread_ != NULL) {
+        status_t res = diag_thread_->startWorkThread();
+        if (res != OK)
+            ALOGW("Failed to start A@H clock recovery diagnostic thread.");
+    } else
+        ALOGW("Failed to allocate diagnostic thread.");
+#endif
+}
+
+ClockRecoveryLoop::~ClockRecoveryLoop() {
+#ifdef TIME_SERVICE_DEBUG
+    diag_thread_->stopWorkThread();
+#endif
+}
+
+// Constants.
+const float ClockRecoveryLoop::dT = 1.0;
+const float ClockRecoveryLoop::Kc = 1.0f;
+const float ClockRecoveryLoop::Ti = 15.0f;
+const float ClockRecoveryLoop::Tf = 0.05;
+const float ClockRecoveryLoop::bias_Fc = 0.01;
+const float ClockRecoveryLoop::bias_RC = (dT / (2 * 3.14159f * bias_Fc));
+const float ClockRecoveryLoop::bias_Alpha = (dT / (bias_RC + dT));
+const int64_t ClockRecoveryLoop::panic_thresh_ = 50000;
+const int64_t ClockRecoveryLoop::control_thresh_ = 10000;
+const float ClockRecoveryLoop::COmin = -100.0f;
+const float ClockRecoveryLoop::COmax = 100.0f;
+const uint32_t ClockRecoveryLoop::kMinFullRangeSlewChange_mSec = 300;
+const int ClockRecoveryLoop::kSlewChangeStepPeriod_mSec = 10;
+
+
+void ClockRecoveryLoop::reset(bool position, bool frequency) {
+    Mutex::Autolock lock(&lock_);
+    reset_l(position, frequency);
+}
+
+uint32_t ClockRecoveryLoop::findMinRTTNdx(DisciplineDataPoint* data,
+                                          uint32_t count) {
+    uint32_t min_rtt = 0;
+    for (uint32_t i = 1; i < count; ++i)
+        if (data[min_rtt].rtt > data[i].rtt)
+            min_rtt = i;
+
+    return min_rtt;
+}
+
+bool ClockRecoveryLoop::pushDisciplineEvent(int64_t local_time,
+                                            int64_t nominal_common_time,
+                                            int64_t rtt) {
+    Mutex::Autolock lock(&lock_);
+
+    int64_t local_common_time = 0;
+    common_clock_->localToCommon(local_time, &local_common_time);
+    int64_t raw_delta = nominal_common_time - local_common_time;
+
+#ifdef TIME_SERVICE_DEBUG
+    ALOGE("local=%lld, common=%lld, delta=%lld, rtt=%lld\n",
+         local_common_time, nominal_common_time,
+         raw_delta, rtt);
+#endif
+
+    // If we have not defined a basis for common time, then we need to use these
+    // initial points to do so.  In order to avoid significant initial error
+    // from a particularly bad startup data point, we collect the first N data
+    // points and choose the best of them before moving on.
+    if (!common_clock_->isValid()) {
+        if (startup_filter_wr_ < kStartupFilterSize) {
+            DisciplineDataPoint& d =  startup_filter_data_[startup_filter_wr_];
+            d.local_time = local_time;
+            d.nominal_common_time = nominal_common_time;
+            d.rtt = rtt;
+            startup_filter_wr_++;
+        }
+
+        if (startup_filter_wr_ == kStartupFilterSize) {
+            uint32_t min_rtt = findMinRTTNdx(startup_filter_data_,
+                    kStartupFilterSize);
+
+            common_clock_->setBasis(
+                    startup_filter_data_[min_rtt].local_time,
+                    startup_filter_data_[min_rtt].nominal_common_time);
+        }
+
+        return true;
+    }
+
+    int64_t observed_common;
+    int64_t delta;
+    float delta_f, dCO;
+    int32_t tgt_correction;
+
+    if (OK != common_clock_->localToCommon(local_time, &observed_common)) {
+        // Since we just checked to make certain that this conversion was valid,
+        // and no one else in the system should be messing with it, if this
+        // conversion is suddenly invalid, it is a good reason to panic.
+        ALOGE("Failed to convert local time to common time in %s:%d",
+                __PRETTY_FUNCTION__, __LINE__);
+        return false;
+    }
+
+    // Implement a filter which should match NTP filtering behavior when a
+    // client is associated with only one peer of lower stratum.  Basically,
+    // always use the best of the N last data points, where best is defined as
+    // lowest round trip time.  NTP uses an N of 8; we use a value of 6.
+    //
+    // TODO(johngro) : experiment with other filter strategies.  The goal here
+    // is to mitigate the effects of high RTT data points which typically have
+    // large asymmetries in the TX/RX legs.  Downside of the existing NTP
+    // approach (particularly because of the PID controller we are using to
+    // produce the control signal from the filtered data) are that the rate at
+    // which discipline events are actually acted upon becomes irregular and can
+    // become drawn out (the time between actionable event can go way up).  If
+    // the system receives a strong high quality data point, the proportional
+    // component of the controller can produce a strong correction which is left
+    // in place for too long causing overshoot.  In addition, the integral
+    // component of the system currently is an approximation based on the
+    // assumption of a more or less homogeneous sampling of the error.  Its
+    // unclear what the effect of undermining this assumption would be right
+    // now.
+
+    // Two ideas which come to mind immediately would be to...
+    // 1) Keep a history of more data points (32 or so) and ignore data points
+    //    whose RTT is more than a certain number of standard deviations outside
+    //    of the norm.
+    // 2) Eliminate the PID controller portion of this system entirely.
+    //    Instead, move to a system which uses a very wide filter (128 data
+    //    points or more) with a sum-of-least-squares line fitting approach to
+    //    tracking the long term drift.  This would take the place of the I
+    //    component in the current PID controller.  Also use a much more narrow
+    //    outlier-rejector filter (as described in #1) to drive a short term
+    //    correction factor similar to the P component of the PID controller.
+    assert(filter_wr_ < kFilterSize);
+    filter_data_[filter_wr_].local_time           = local_time;
+    filter_data_[filter_wr_].observed_common_time = observed_common;
+    filter_data_[filter_wr_].nominal_common_time  = nominal_common_time;
+    filter_data_[filter_wr_].rtt                  = rtt;
+    filter_data_[filter_wr_].point_used           = false;
+    uint32_t current_point = filter_wr_;
+    filter_wr_ = (filter_wr_ + 1) % kFilterSize;
+    if (!filter_wr_)
+        filter_full_ = true;
+
+    uint32_t scan_end = filter_full_ ? kFilterSize : filter_wr_;
+    uint32_t min_rtt = findMinRTTNdx(filter_data_, scan_end);
+    // We only use packets with low RTTs for control. If the packet RTT
+    // is less than the panic threshold, we can probably eat the jitter with the
+    // control loop. Otherwise, take the packet only if it better than all
+    // of the packets we have in the history. That way we try to track
+    // something, even if it is noisy.
+    if (current_point == min_rtt || rtt < control_thresh_) {
+        delta_f = delta = nominal_common_time - observed_common;
+
+        last_error_est_valid_ = true;
+        last_error_est_usec_ = delta;
+
+        // Compute the error then clamp to the panic threshold.  If we ever
+        // exceed this amt of error, its time to panic and reset the system.
+        // Given that the error in the measurement of the error could be as
+        // high as the RTT of the data point, we don't actually panic until
+        // the implied error (delta) is greater than the absolute panic
+        // threashold plus the RTT.  IOW - we don't panic until we are
+        // absoluely sure that our best case sync is worse than the absolute
+        // panic threshold.
+        int64_t effective_panic_thresh = panic_thresh_ + rtt;
+        if ((delta > effective_panic_thresh) ||
+            (delta < -effective_panic_thresh)) {
+            // PANIC!!!
+            reset_l(false, true);
+            return false;
+        }
+
+    } else {
+        // We do not have a good packet to look at, but we also do not want to
+        // free-run the clock at some crazy slew rate. So we guess the
+        // trajectory of the clock based on the last controller output and the
+        // estimated bias of our clock against the master.
+        // The net effect of this is that CO == CObias after some extended
+        // period of no feedback.
+        delta_f = last_delta_f_ - dT*(CO - CObias);
+        delta = delta_f;
+    }
+
+    // Velocity form PI control equation.
+    dCO = Kc * (1.0f + dT/Ti) * delta_f - Kc * last_delta_f_;
+    CO += dCO * Tf; // Filter CO by applying gain <1 here.
+
+    // Save error terms for later.
+    last_delta_f_ = delta_f;
+
+    // Clamp CO to +/- 100ppm.
+    if (CO < COmin)
+        CO = COmin;
+    else if (CO > COmax)
+        CO = COmax;
+
+    // Update the controller bias.
+    CObias = bias_Alpha * CO + (1.0f - bias_Alpha) * lastCObias;
+    lastCObias = CObias;
+
+    // Convert PPM to 16-bit int range. Add some guard band (-0.01) so we
+    // don't get fp weirdness.
+    tgt_correction = CO * 327.66;
+
+    // If there was a change in the amt of correction to use, update the
+    // system.
+    setTargetCorrection_l(tgt_correction);
+
+    LOG_TS("clock_loop %lld %f %f %f %d\n", raw_delta, delta_f, CO, CObias, tgt_correction);
+
+#ifdef TIME_SERVICE_DEBUG
+    diag_thread_->pushDisciplineEvent(
+            local_time,
+            observed_common,
+            nominal_common_time,
+            tgt_correction,
+            rtt);
+#endif
+
+    return true;
+}
+
+int32_t ClockRecoveryLoop::getLastErrorEstimate() {
+    Mutex::Autolock lock(&lock_);
+
+    if (last_error_est_valid_)
+        return last_error_est_usec_;
+    else
+        return ICommonClock::kErrorEstimateUnknown;
+}
+
+void ClockRecoveryLoop::reset_l(bool position, bool frequency) {
+    assert(NULL != common_clock_);
+
+    if (position) {
+        common_clock_->resetBasis();
+        startup_filter_wr_ = 0;
+    }
+
+    if (frequency) {
+        last_error_est_valid_ = false;
+        last_error_est_usec_ = 0;
+        last_delta_f_ = 0.0;
+        CO = 0.0f;
+        lastCObias = CObias = 0.0f;
+        setTargetCorrection_l(0);
+        applySlew_l();
+    }
+
+    filter_wr_   = 0;
+    filter_full_ = false;
+}
+
+void ClockRecoveryLoop::setTargetCorrection_l(int32_t tgt) {
+    // When we make a change to the slew rate, we need to be careful to not
+    // change it too quickly as it can anger some HDMI sinks out there, notably
+    // some Sony panels from the 2010-2011 timeframe.  From experimenting with
+    // some of these sinks, it seems like swinging from one end of the range to
+    // another in less that 190mSec or so can start to cause trouble.  Adding in
+    // a hefty margin, we limit the system to a full range sweep in no less than
+    // 300mSec.
+    if (tgt_correction_ != tgt) {
+        int64_t now = local_clock_->getLocalTime();
+        status_t res;
+
+        tgt_correction_ = tgt;
+
+        // Set up the transformation to figure out what the slew should be at
+        // any given point in time in the future.
+        time_to_cur_slew_.a_zero = now;
+        time_to_cur_slew_.b_zero = cur_correction_;
+
+        // Make sure the sign of the slope is headed in the proper direction.
+        bool needs_increase = (cur_correction_ < tgt_correction_);
+        bool is_increasing  = (time_to_cur_slew_.a_to_b_numer > 0);
+        if (( needs_increase && !is_increasing) ||
+            (!needs_increase &&  is_increasing)) {
+            time_to_cur_slew_.a_to_b_numer = -time_to_cur_slew_.a_to_b_numer;
+        }
+
+        // Finally, figure out when the change will be finished and start the
+        // slew operation.
+        time_to_cur_slew_.doReverseTransform(tgt_correction_,
+                                             &slew_change_end_time_);
+
+        applySlew_l();
+    }
+}
+
+bool ClockRecoveryLoop::applySlew_l() {
+    bool ret = true;
+
+    // If cur == tgt, there is no ongoing sleq rate change and we are already
+    // finished.
+    if (cur_correction_ == tgt_correction_)
+        goto bailout;
+
+    if (local_clock_can_slew_) {
+        int64_t now = local_clock_->getLocalTime();
+        int64_t tmp;
+
+        if (now >= slew_change_end_time_) {
+            cur_correction_ = tgt_correction_;
+            next_slew_change_timeout_.setTimeout(-1);
+        } else {
+            time_to_cur_slew_.doForwardTransform(now, &tmp);
+
+            if (tmp > INT16_MAX)
+                cur_correction_ = INT16_MAX;
+            else if (tmp < INT16_MIN)
+                cur_correction_ = INT16_MIN;
+            else
+                cur_correction_ = static_cast<int16_t>(tmp);
+
+            next_slew_change_timeout_.setTimeout(kSlewChangeStepPeriod_mSec);
+            ret = false;
+        }
+
+        local_clock_->setLocalSlew(cur_correction_);
+    } else {
+        // Since we are not actually changing the rate of a HW clock, we don't
+        // need to worry to much about changing the slew rate so fast that we
+        // anger any downstream HDMI devices.
+        cur_correction_ = tgt_correction_;
+        next_slew_change_timeout_.setTimeout(-1);
+
+        // The SW clock recovery implemented by the common clock class expects
+        // values expressed in PPM. CO is in ppm.
+        common_clock_->setSlew(local_clock_->getLocalTime(), CO);
+    }
+
+bailout:
+    return ret;
+}
+
+int ClockRecoveryLoop::applyRateLimitedSlew() {
+    Mutex::Autolock lock(&lock_);
+
+    int ret = next_slew_change_timeout_.msecTillTimeout();
+    if (!ret) {
+        if (applySlew_l())
+            next_slew_change_timeout_.setTimeout(-1);
+        ret = next_slew_change_timeout_.msecTillTimeout();
+    }
+
+    return ret;
+}
+
+}  // namespace android
diff --git a/libs/common_time/clock_recovery.h b/libs/common_time/clock_recovery.h
new file mode 100644
index 0000000..b6c87ff
--- /dev/null
+++ b/libs/common_time/clock_recovery.h
@@ -0,0 +1,159 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __CLOCK_RECOVERY_H__
+#define __CLOCK_RECOVERY_H__
+
+#include <stdint.h>
+#include <common_time/ICommonClock.h>
+#include <utils/LinearTransform.h>
+#include <utils/threads.h>
+
+#ifdef TIME_SERVICE_DEBUG
+#include "diag_thread.h"
+#endif
+
+#include "utils.h"
+
+namespace android {
+
+class CommonClock;
+class LocalClock;
+
+class ClockRecoveryLoop {
+  public:
+     ClockRecoveryLoop(LocalClock* local_clock, CommonClock* common_clock);
+    ~ClockRecoveryLoop();
+
+    void reset(bool position, bool frequency);
+    bool pushDisciplineEvent(int64_t local_time,
+                             int64_t nominal_common_time,
+                             int64_t data_point_rtt);
+    int32_t getLastErrorEstimate();
+
+    // Applies the next step in any ongoing slew change operation.  Returns a
+    // timeout suitable for use with poll/select indicating the number of mSec
+    // until the next change should be applied.
+    int applyRateLimitedSlew();
+
+  private:
+
+    // Tuned using the "Good Gain" method.
+    // See:
+    // http://techteach.no/publications/books/dynamics_and_control/tuning_pid_controller.pdf
+
+    // Controller period (1Hz for now).
+    static const float dT;
+
+    // Controller gain, positive and unitless. Larger values converge faster,
+    // but can cause instability.
+    static const float Kc;
+
+    // Integral reset time. Smaller values cause loop to track faster, but can
+    // also cause instability.
+    static const float Ti;
+
+    // Controller output filter time constant. Range (0-1). Smaller values make
+    // output smoother, but slow convergence.
+    static const float Tf;
+
+    // Low-pass filter for bias tracker.
+    static const float bias_Fc; // HZ
+    static const float bias_RC; // Computed in constructor.
+    static const float bias_Alpha; // Computed inconstructor.
+
+    // The maximum allowed error (as indicated by a  pushDisciplineEvent) before
+    // we panic.
+    static const int64_t panic_thresh_;
+
+    // The maximum allowed error rtt time for packets to be used for control
+    // feedback, unless the packet is the best in recent memory.
+    static const int64_t control_thresh_;
+
+    typedef struct {
+        int64_t local_time;
+        int64_t observed_common_time;
+        int64_t nominal_common_time;
+        int64_t rtt;
+        bool point_used;
+    } DisciplineDataPoint;
+
+    static uint32_t findMinRTTNdx(DisciplineDataPoint* data, uint32_t count);
+
+    void reset_l(bool position, bool frequency);
+    void setTargetCorrection_l(int32_t tgt);
+    bool applySlew_l();
+
+    // The local clock HW abstraction we use as the basis for common time.
+    LocalClock* local_clock_;
+    bool local_clock_can_slew_;
+
+    // The common clock we end up controlling along with the lock used to
+    // serialize operations.
+    CommonClock* common_clock_;
+    Mutex lock_;
+
+    // parameters maintained while running and reset during a reset
+    // of the frequency correction.
+    bool    last_error_est_valid_;
+    int32_t last_error_est_usec_;
+    float last_delta_f_;
+    int32_t integrated_error_;
+    int32_t tgt_correction_;
+    int32_t cur_correction_;
+    LinearTransform time_to_cur_slew_;
+    int64_t slew_change_end_time_;
+    Timeout next_slew_change_timeout_;
+
+    // Contoller Output.
+    float CO;
+
+    // Bias tracking for trajectory estimation.
+    float CObias;
+    float lastCObias;
+
+    // Controller output bounds. The controller will not try to
+    // slew faster that +/-100ppm offset from center per interation.
+    static const float COmin;
+    static const float COmax;
+
+    // State kept for filtering the discipline data.
+    static const uint32_t kFilterSize = 16;
+    DisciplineDataPoint filter_data_[kFilterSize];
+    uint32_t filter_wr_;
+    bool filter_full_;
+
+    static const uint32_t kStartupFilterSize = 4;
+    DisciplineDataPoint startup_filter_data_[kStartupFilterSize];
+    uint32_t startup_filter_wr_;
+
+    // Minimum number of milliseconds over which we allow a full range change
+    // (from rail to rail) of the VCXO control signal.  This is the rate
+    // limiting factor which keeps us from changing the clock rate so fast that
+    // we get in trouble with certain HDMI sinks.
+    static const uint32_t kMinFullRangeSlewChange_mSec;
+
+    // How much time (in msec) to wait 
+    static const int kSlewChangeStepPeriod_mSec;
+
+#ifdef TIME_SERVICE_DEBUG
+    sp<DiagThread> diag_thread_;
+#endif
+};
+
+}  // namespace android
+
+#endif  // __CLOCK_RECOVERY_H__
diff --git a/libs/common_time/common_clock.cpp b/libs/common_time/common_clock.cpp
new file mode 100644
index 0000000..c9eb388
--- /dev/null
+++ b/libs/common_time/common_clock.cpp
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define __STDC_LIMIT_MACROS
+
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+
+#include <stdint.h>
+
+#include <utils/Errors.h>
+#include <utils/LinearTransform.h>
+
+#include "common_clock.h"
+
+namespace android {
+
+CommonClock::CommonClock() {
+    cur_slew_        = 0;
+    cur_trans_valid_ = false;
+
+    cur_trans_.a_zero = 0;
+    cur_trans_.b_zero = 0;
+    cur_trans_.a_to_b_numer = local_to_common_freq_numer_ = 1;
+    cur_trans_.a_to_b_denom = local_to_common_freq_denom_ = 1;
+    duration_trans_ = cur_trans_;
+}
+
+bool CommonClock::init(uint64_t local_freq) {
+    Mutex::Autolock lock(&lock_);
+
+    if (!local_freq)
+        return false;
+
+    uint64_t numer = kCommonFreq;
+    uint64_t denom = local_freq;
+
+    LinearTransform::reduce(&numer, &denom);
+    if ((numer > UINT32_MAX) || (denom > UINT32_MAX)) {
+        ALOGE("Overflow in CommonClock::init while trying to reduce %lld/%lld",
+             kCommonFreq, local_freq);
+        return false;
+    }
+
+    cur_trans_.a_to_b_numer = local_to_common_freq_numer_ =
+        static_cast<uint32_t>(numer);
+    cur_trans_.a_to_b_denom = local_to_common_freq_denom_ =
+        static_cast<uint32_t>(denom);
+    duration_trans_ = cur_trans_;
+
+    return true;
+}
+
+status_t CommonClock::localToCommon(int64_t local, int64_t *common_out) const {
+    Mutex::Autolock lock(&lock_);
+
+    if (!cur_trans_valid_)
+        return INVALID_OPERATION;
+
+    if (!cur_trans_.doForwardTransform(local, common_out))
+        return INVALID_OPERATION;
+
+    return OK;
+}
+
+status_t CommonClock::commonToLocal(int64_t common, int64_t *local_out) const {
+    Mutex::Autolock lock(&lock_);
+
+    if (!cur_trans_valid_)
+        return INVALID_OPERATION;
+
+    if (!cur_trans_.doReverseTransform(common, local_out))
+        return INVALID_OPERATION;
+
+    return OK;
+}
+
+int64_t CommonClock::localDurationToCommonDuration(int64_t localDur) const {
+    int64_t ret;
+    duration_trans_.doForwardTransform(localDur, &ret);
+    return ret;
+}
+
+void CommonClock::setBasis(int64_t local, int64_t common) {
+    Mutex::Autolock lock(&lock_);
+
+    cur_trans_.a_zero = local;
+    cur_trans_.b_zero = common;
+    cur_trans_valid_ = true;
+}
+
+void CommonClock::resetBasis() {
+    Mutex::Autolock lock(&lock_);
+
+    cur_trans_.a_zero = 0;
+    cur_trans_.b_zero = 0;
+    cur_trans_valid_ = false;
+}
+
+status_t CommonClock::setSlew(int64_t change_time, int32_t ppm) {
+    Mutex::Autolock lock(&lock_);
+
+    int64_t new_local_basis;
+    int64_t new_common_basis;
+
+    if (cur_trans_valid_) {
+        new_local_basis = change_time;
+        if (!cur_trans_.doForwardTransform(change_time, &new_common_basis)) {
+            ALOGE("Overflow when attempting to set slew rate to %d", ppm);
+            return INVALID_OPERATION;
+        }
+    } else {
+        new_local_basis = 0;
+        new_common_basis = 0;
+    }
+
+    cur_slew_ = ppm;
+    uint32_t n1 = local_to_common_freq_numer_;
+    uint32_t n2 = 1000000 + cur_slew_;
+
+    uint32_t d1 = local_to_common_freq_denom_;
+    uint32_t d2 = 1000000;
+
+    // n1/d1 has already been reduced, no need to do so here.
+    LinearTransform::reduce(&n1, &d2);
+    LinearTransform::reduce(&n2, &d1);
+    LinearTransform::reduce(&n2, &d2);
+
+    cur_trans_.a_zero = new_local_basis;
+    cur_trans_.b_zero = new_common_basis;
+    cur_trans_.a_to_b_numer = n1 * n2;
+    cur_trans_.a_to_b_denom = d1 * d2;
+
+    return OK;
+}
+
+}  // namespace android
diff --git a/libs/common_time/common_clock.h b/libs/common_time/common_clock.h
new file mode 100644
index 0000000..b786fdc
--- /dev/null
+++ b/libs/common_time/common_clock.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __COMMON_CLOCK_H__
+#define __COMMON_CLOCK_H__
+
+#include <stdint.h>
+
+#include <utils/Errors.h>
+#include <utils/LinearTransform.h>
+#include <utils/threads.h>
+
+namespace android {
+
+class CommonClock {
+  public:
+    CommonClock();
+
+    bool      init(uint64_t local_freq);
+
+    status_t  localToCommon(int64_t local, int64_t *common_out) const;
+    status_t  commonToLocal(int64_t common, int64_t *local_out) const;
+    int64_t   localDurationToCommonDuration(int64_t localDur) const;
+    uint64_t  getCommonFreq() const { return kCommonFreq; }
+    bool      isValid() const { return cur_trans_valid_; }
+    status_t  setSlew(int64_t change_time, int32_t ppm);
+    void      setBasis(int64_t local, int64_t common);
+    void      resetBasis();
+  private:
+    mutable Mutex lock_;
+
+    int32_t  cur_slew_;
+    uint32_t local_to_common_freq_numer_;
+    uint32_t local_to_common_freq_denom_;
+
+    LinearTransform duration_trans_;
+    LinearTransform cur_trans_;
+    bool cur_trans_valid_;
+
+    static const uint64_t kCommonFreq = 1000000ull;
+};
+
+}  // namespace android
+#endif  // __COMMON_CLOCK_H__
diff --git a/libs/common_time/common_clock_service.cpp b/libs/common_time/common_clock_service.cpp
new file mode 100644
index 0000000..9ca6f35
--- /dev/null
+++ b/libs/common_time/common_clock_service.cpp
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <common_time/local_clock.h>
+#include <utils/String8.h>
+
+#include "common_clock_service.h"
+#include "common_clock.h"
+#include "common_time_server.h"
+
+namespace android {
+
+sp<CommonClockService> CommonClockService::instantiate(
+        CommonTimeServer& timeServer) {
+    sp<CommonClockService> tcc = new CommonClockService(timeServer);
+    if (tcc == NULL)
+        return NULL;
+
+    defaultServiceManager()->addService(ICommonClock::kServiceName, tcc);
+    return tcc;
+}
+
+status_t CommonClockService::dump(int fd, const Vector<String16>& args) {
+    Mutex::Autolock lock(mRegistrationLock);
+    return mTimeServer.dumpClockInterface(fd, args, mListeners.size());
+}
+
+status_t CommonClockService::isCommonTimeValid(bool* valid,
+                                               uint32_t* timelineID) {
+    return mTimeServer.isCommonTimeValid(valid, timelineID);
+}
+
+status_t CommonClockService::commonTimeToLocalTime(int64_t  commonTime,
+                                                   int64_t* localTime) {
+    return mTimeServer.getCommonClock().commonToLocal(commonTime, localTime);
+}
+
+status_t CommonClockService::localTimeToCommonTime(int64_t  localTime,
+                                                   int64_t* commonTime) {
+    return mTimeServer.getCommonClock().localToCommon(localTime, commonTime);
+}
+
+status_t CommonClockService::getCommonTime(int64_t* commonTime) {
+    return localTimeToCommonTime(mTimeServer.getLocalClock().getLocalTime(), commonTime);
+}
+
+status_t CommonClockService::getCommonFreq(uint64_t* freq) {
+    *freq = mTimeServer.getCommonClock().getCommonFreq();
+    return OK;
+}
+
+status_t CommonClockService::getLocalTime(int64_t* localTime) {
+    *localTime = mTimeServer.getLocalClock().getLocalTime();
+    return OK;
+}
+
+status_t CommonClockService::getLocalFreq(uint64_t* freq) {
+    *freq = mTimeServer.getLocalClock().getLocalFreq();
+    return OK;
+}
+
+status_t CommonClockService::getEstimatedError(int32_t* estimate) {
+    *estimate = mTimeServer.getEstimatedError();
+    return OK;
+}
+
+status_t CommonClockService::getTimelineID(uint64_t* id) {
+    *id = mTimeServer.getTimelineID();
+    return OK;
+}
+
+status_t CommonClockService::getState(State* state) {
+    *state = mTimeServer.getState();
+    return OK;
+}
+
+status_t CommonClockService::getMasterAddr(struct sockaddr_storage* addr) {
+    return mTimeServer.getMasterAddr(addr);
+}
+
+status_t CommonClockService::registerListener(
+        const sp<ICommonClockListener>& listener) {
+    Mutex::Autolock lock(mRegistrationLock);
+
+    {   // scoping for autolock pattern
+        Mutex::Autolock lock(mCallbackLock);
+        // check whether this is a duplicate
+        for (size_t i = 0; i < mListeners.size(); i++) {
+            if (mListeners[i]->asBinder() == listener->asBinder())
+                return ALREADY_EXISTS;
+        }
+    }
+
+    mListeners.add(listener);
+    mTimeServer.reevaluateAutoDisableState(0 != mListeners.size());
+    return listener->asBinder()->linkToDeath(this);
+}
+
+status_t CommonClockService::unregisterListener(
+        const sp<ICommonClockListener>& listener) {
+    Mutex::Autolock lock(mRegistrationLock);
+    status_t ret_val = NAME_NOT_FOUND;
+
+    {   // scoping for autolock pattern
+        Mutex::Autolock lock(mCallbackLock);
+        for (size_t i = 0; i < mListeners.size(); i++) {
+            if (mListeners[i]->asBinder() == listener->asBinder()) {
+                mListeners[i]->asBinder()->unlinkToDeath(this);
+                mListeners.removeAt(i);
+                ret_val = OK;
+                break;
+            }
+        }
+    }
+
+    mTimeServer.reevaluateAutoDisableState(0 != mListeners.size());
+    return ret_val;
+}
+
+void CommonClockService::binderDied(const wp<IBinder>& who) {
+    Mutex::Autolock lock(mRegistrationLock);
+
+    {   // scoping for autolock pattern
+        Mutex::Autolock lock(mCallbackLock);
+        for (size_t i = 0; i < mListeners.size(); i++) {
+            if (mListeners[i]->asBinder() == who) {
+                mListeners.removeAt(i);
+                break;
+            }
+        }
+    }
+
+    mTimeServer.reevaluateAutoDisableState(0 != mListeners.size());
+}
+
+void CommonClockService::notifyOnTimelineChanged(uint64_t timelineID) {
+    Mutex::Autolock lock(mCallbackLock);
+
+    for (size_t i = 0; i < mListeners.size(); i++) {
+        mListeners[i]->onTimelineChanged(timelineID);
+    }
+}
+
+}; // namespace android
diff --git a/libs/common_time/common_clock_service.h b/libs/common_time/common_clock_service.h
new file mode 100644
index 0000000..bd663f0
--- /dev/null
+++ b/libs/common_time/common_clock_service.h
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_COMMON_CLOCK_SERVICE_H
+#define ANDROID_COMMON_CLOCK_SERVICE_H
+
+#include <sys/socket.h>
+#include <common_time/ICommonClock.h>
+
+namespace android {
+
+class CommonTimeServer;
+
+class CommonClockService : public BnCommonClock,
+                           public android::IBinder::DeathRecipient {
+  public:
+    static sp<CommonClockService> instantiate(CommonTimeServer& timeServer);
+
+    virtual status_t dump(int fd, const Vector<String16>& args);
+
+    virtual status_t isCommonTimeValid(bool* valid, uint32_t *timelineID);
+    virtual status_t commonTimeToLocalTime(int64_t  common_time,
+                                           int64_t* local_time);
+    virtual status_t localTimeToCommonTime(int64_t  local_time,
+                                           int64_t* common_time);
+    virtual status_t getCommonTime(int64_t* common_time);
+    virtual status_t getCommonFreq(uint64_t* freq);
+    virtual status_t getLocalTime(int64_t* local_time);
+    virtual status_t getLocalFreq(uint64_t* freq);
+    virtual status_t getEstimatedError(int32_t* estimate);
+    virtual status_t getTimelineID(uint64_t* id);
+    virtual status_t getState(ICommonClock::State* state);
+    virtual status_t getMasterAddr(struct sockaddr_storage* addr);
+
+    virtual status_t registerListener(
+            const sp<ICommonClockListener>& listener);
+    virtual status_t unregisterListener(
+            const sp<ICommonClockListener>& listener);
+
+    void notifyOnTimelineChanged(uint64_t timelineID);
+
+  private:
+    CommonClockService(CommonTimeServer& timeServer)
+        : mTimeServer(timeServer) { };
+
+    virtual void binderDied(const wp<IBinder>& who);
+
+    CommonTimeServer& mTimeServer;
+
+    // locks used to synchronize access to the list of registered listeners.
+    // The callback lock is held whenever the list is used to perform callbacks
+    // or while the list is being modified.  The registration lock used to
+    // serialize access across registerListener, unregisterListener, and
+    // binderDied.
+    //
+    // The reason for two locks is that registerListener, unregisterListener,
+    // and binderDied each call into the core service and obtain the core
+    // service thread lock when they call reevaluateAutoDisableState.  The core
+    // service thread obtains the main thread lock whenever its thread is
+    // running, and sometimes needs to call notifyOnTimelineChanged which then
+    // obtains the callback lock.  If callers of registration functions were
+    // holding the callback lock when they called into the core service, we
+    // would have a classic A/B, B/A ordering deadlock.  To avoid this, the
+    // registration functions hold the registration lock for the duration of
+    // their call, but hold the callback lock only while they mutate the list.
+    // This way, the list's size cannot change (because of the registration
+    // lock) during the call into reevaluateAutoDisableState, but the core work
+    // thread can still safely call notifyOnTimelineChanged while holding the
+    // main thread lock.
+    Mutex mCallbackLock;
+    Mutex mRegistrationLock;
+
+    Vector<sp<ICommonClockListener> > mListeners;
+};
+
+};  // namespace android
+
+#endif  // ANDROID_COMMON_CLOCK_SERVICE_H
diff --git a/libs/common_time/common_time_config_service.cpp b/libs/common_time/common_time_config_service.cpp
new file mode 100644
index 0000000..9585618
--- /dev/null
+++ b/libs/common_time/common_time_config_service.cpp
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <utils/String8.h>
+
+#include "common_time_config_service.h"
+#include "common_time_server.h"
+
+namespace android {
+
+sp<CommonTimeConfigService> CommonTimeConfigService::instantiate(
+        CommonTimeServer& timeServer) {
+    sp<CommonTimeConfigService> ctcs = new CommonTimeConfigService(timeServer);
+    if (ctcs == NULL)
+        return NULL;
+
+    defaultServiceManager()->addService(ICommonTimeConfig::kServiceName, ctcs);
+    return ctcs;
+}
+
+status_t CommonTimeConfigService::dump(int fd, const Vector<String16>& args) {
+    return mTimeServer.dumpConfigInterface(fd, args);
+}
+
+status_t CommonTimeConfigService::getMasterElectionPriority(uint8_t *priority) {
+    return mTimeServer.getMasterElectionPriority(priority);
+}
+
+status_t CommonTimeConfigService::setMasterElectionPriority(uint8_t priority) {
+    return mTimeServer.setMasterElectionPriority(priority);
+}
+
+status_t CommonTimeConfigService::getMasterElectionEndpoint(
+        struct sockaddr_storage *addr) {
+    return mTimeServer.getMasterElectionEndpoint(addr);
+}
+
+status_t CommonTimeConfigService::setMasterElectionEndpoint(
+        const struct sockaddr_storage *addr) {
+    return mTimeServer.setMasterElectionEndpoint(addr);
+}
+
+status_t CommonTimeConfigService::getMasterElectionGroupId(uint64_t *id) {
+    return mTimeServer.getMasterElectionGroupId(id);
+}
+
+status_t CommonTimeConfigService::setMasterElectionGroupId(uint64_t id) {
+    return mTimeServer.setMasterElectionGroupId(id);
+}
+
+status_t CommonTimeConfigService::getInterfaceBinding(String16& ifaceName) {
+    String8 tmp;
+    status_t ret = mTimeServer.getInterfaceBinding(tmp);
+    ifaceName = String16(tmp);
+    return ret;
+}
+
+status_t CommonTimeConfigService::setInterfaceBinding(const String16& ifaceName) {
+    String8 tmp(ifaceName);
+    return mTimeServer.setInterfaceBinding(tmp);
+}
+
+status_t CommonTimeConfigService::getMasterAnnounceInterval(int *interval) {
+    return mTimeServer.getMasterAnnounceInterval(interval);
+}
+
+status_t CommonTimeConfigService::setMasterAnnounceInterval(int interval) {
+    return mTimeServer.setMasterAnnounceInterval(interval);
+}
+
+status_t CommonTimeConfigService::getClientSyncInterval(int *interval) {
+    return mTimeServer.getClientSyncInterval(interval);
+}
+
+status_t CommonTimeConfigService::setClientSyncInterval(int interval) {
+    return mTimeServer.setClientSyncInterval(interval);
+}
+
+status_t CommonTimeConfigService::getPanicThreshold(int *threshold) {
+    return mTimeServer.getPanicThreshold(threshold);
+}
+
+status_t CommonTimeConfigService::setPanicThreshold(int threshold) {
+    return mTimeServer.setPanicThreshold(threshold);
+}
+
+status_t CommonTimeConfigService::getAutoDisable(bool *autoDisable) {
+    return mTimeServer.getAutoDisable(autoDisable);
+}
+
+status_t CommonTimeConfigService::setAutoDisable(bool autoDisable) {
+    return mTimeServer.setAutoDisable(autoDisable);
+}
+
+status_t CommonTimeConfigService::forceNetworklessMasterMode() {
+    return mTimeServer.forceNetworklessMasterMode();
+}
+
+}; // namespace android
diff --git a/libs/common_time/common_time_config_service.h b/libs/common_time/common_time_config_service.h
new file mode 100644
index 0000000..89806dd
--- /dev/null
+++ b/libs/common_time/common_time_config_service.h
@@ -0,0 +1,60 @@
+/* * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_COMMON_TIME_CONFIG_SERVICE_H
+#define ANDROID_COMMON_TIME_CONFIG_SERVICE_H
+
+#include <sys/socket.h>
+#include <common_time/ICommonTimeConfig.h>
+
+namespace android {
+
+class String16;
+class CommonTimeServer;
+
+class CommonTimeConfigService : public BnCommonTimeConfig {
+  public:
+    static sp<CommonTimeConfigService> instantiate(CommonTimeServer& timeServer);
+
+    virtual status_t dump(int fd, const Vector<String16>& args);
+
+    virtual status_t getMasterElectionPriority(uint8_t *priority);
+    virtual status_t setMasterElectionPriority(uint8_t priority);
+    virtual status_t getMasterElectionEndpoint(struct sockaddr_storage *addr);
+    virtual status_t setMasterElectionEndpoint(const struct sockaddr_storage *addr);
+    virtual status_t getMasterElectionGroupId(uint64_t *id);
+    virtual status_t setMasterElectionGroupId(uint64_t id);
+    virtual status_t getInterfaceBinding(String16& ifaceName);
+    virtual status_t setInterfaceBinding(const String16& ifaceName);
+    virtual status_t getMasterAnnounceInterval(int *interval);
+    virtual status_t setMasterAnnounceInterval(int interval);
+    virtual status_t getClientSyncInterval(int *interval);
+    virtual status_t setClientSyncInterval(int interval);
+    virtual status_t getPanicThreshold(int *threshold);
+    virtual status_t setPanicThreshold(int threshold);
+    virtual status_t getAutoDisable(bool *autoDisable);
+    virtual status_t setAutoDisable(bool autoDisable);
+    virtual status_t forceNetworklessMasterMode();
+
+  private:
+    CommonTimeConfigService(CommonTimeServer& timeServer)
+        : mTimeServer(timeServer) { }
+    CommonTimeServer& mTimeServer;
+
+};
+
+};  // namespace android
+
+#endif  // ANDROID_COMMON_TIME_CONFIG_SERVICE_H
diff --git a/libs/common_time/common_time_server.cpp b/libs/common_time/common_time_server.cpp
new file mode 100644
index 0000000..21e706f
--- /dev/null
+++ b/libs/common_time/common_time_server.cpp
@@ -0,0 +1,1506 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * A service that exchanges time synchronization information between
+ * a master that defines a timeline and clients that follow the timeline.
+ */
+
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+
+#include <arpa/inet.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <linux/if_ether.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <netinet/ip.h>
+#include <poll.h>
+#include <stdio.h>
+#include <sys/eventfd.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <common_time/local_clock.h>
+#include <binder/IPCThreadState.h>
+#include <binder/ProcessState.h>
+#include <utils/Timers.h>
+
+#include "common_clock_service.h"
+#include "common_time_config_service.h"
+#include "common_time_server.h"
+#include "common_time_server_packets.h"
+#include "clock_recovery.h"
+#include "common_clock.h"
+
+#define MAX_INT ((int)0x7FFFFFFF)
+
+namespace android {
+
+const char*    CommonTimeServer::kDefaultMasterElectionAddr = "255.255.255.255";
+const uint16_t CommonTimeServer::kDefaultMasterElectionPort = 8886;
+const uint64_t CommonTimeServer::kDefaultSyncGroupID = 1;
+const uint8_t  CommonTimeServer::kDefaultMasterPriority = 1;
+const uint32_t CommonTimeServer::kDefaultMasterAnnounceIntervalMs = 10000;
+const uint32_t CommonTimeServer::kDefaultSyncRequestIntervalMs = 1000;
+const uint32_t CommonTimeServer::kDefaultPanicThresholdUsec = 50000;
+const bool     CommonTimeServer::kDefaultAutoDisable = true;
+const int      CommonTimeServer::kSetupRetryTimeoutMs = 30000;
+const int64_t  CommonTimeServer::kNoGoodDataPanicThresholdUsec = 600000000ll;
+const uint32_t CommonTimeServer::kRTTDiscardPanicThreshMultiplier = 5;
+
+// timeout value representing an infinite timeout
+const int CommonTimeServer::kInfiniteTimeout = -1;
+
+/*** Initial state constants ***/
+
+// number of WhoIsMaster attempts sent before giving up
+const int CommonTimeServer::kInitial_NumWhoIsMasterRetries = 6;
+
+// timeout used when waiting for a response to a WhoIsMaster request
+const int CommonTimeServer::kInitial_WhoIsMasterTimeoutMs = 500;
+
+/*** Client state constants ***/
+
+// number of sync requests that can fail before a client assumes its master
+// is dead
+const int CommonTimeServer::kClient_NumSyncRequestRetries = 10;
+
+/*** Master state constants ***/
+
+/*** Ronin state constants ***/
+
+// number of WhoIsMaster attempts sent before declaring ourselves master
+const int CommonTimeServer::kRonin_NumWhoIsMasterRetries = 20;
+
+// timeout used when waiting for a response to a WhoIsMaster request
+const int CommonTimeServer::kRonin_WhoIsMasterTimeoutMs = 500;
+
+/*** WaitForElection state constants ***/
+
+// how long do we wait for an announcement from a master before
+// trying another election?
+const int CommonTimeServer::kWaitForElection_TimeoutMs = 12500;
+
+CommonTimeServer::CommonTimeServer()
+    : Thread(false)
+    , mState(ICommonClock::STATE_INITIAL)
+    , mClockRecovery(&mLocalClock, &mCommonClock)
+    , mSocket(-1)
+    , mLastPacketRxLocalTime(0)
+    , mTimelineID(ICommonClock::kInvalidTimelineID)
+    , mClockSynced(false)
+    , mCommonClockHasClients(false)
+    , mStateChangeLog("Recent State Change Events", 30)
+    , mElectionLog("Recent Master Election Traffic", 30)
+    , mBadPktLog("Recent Bad Packet RX Info", 8)
+    , mInitial_WhoIsMasterRequestTimeouts(0)
+    , mClient_MasterDeviceID(0)
+    , mClient_MasterDevicePriority(0)
+    , mRonin_WhoIsMasterRequestTimeouts(0) {
+    // zero out sync stats
+    resetSyncStats();
+
+    // Setup the master election endpoint to use the default.
+    struct sockaddr_in* meep =
+        reinterpret_cast<struct sockaddr_in*>(&mMasterElectionEP);
+    memset(&mMasterElectionEP, 0, sizeof(mMasterElectionEP));
+    inet_aton(kDefaultMasterElectionAddr, &meep->sin_addr);
+    meep->sin_family = AF_INET;
+    meep->sin_port   = htons(kDefaultMasterElectionPort);
+
+    // Zero out the master endpoint.
+    memset(&mMasterEP, 0, sizeof(mMasterEP));
+    mMasterEPValid    = false;
+    mBindIfaceValid   = false;
+    setForceLowPriority(false);
+
+    // Set all remaining configuration parameters to their defaults.
+    mDeviceID                 = 0;
+    mSyncGroupID              = kDefaultSyncGroupID;
+    mMasterPriority           = kDefaultMasterPriority;
+    mMasterAnnounceIntervalMs = kDefaultMasterAnnounceIntervalMs;
+    mSyncRequestIntervalMs    = kDefaultSyncRequestIntervalMs;
+    mPanicThresholdUsec       = kDefaultPanicThresholdUsec;
+    mAutoDisable              = kDefaultAutoDisable;
+
+    // Create the eventfd we will use to signal our thread to wake up when
+    // needed.
+    mWakeupThreadFD = eventfd(0, EFD_NONBLOCK);
+
+    // seed the random number generator (used to generated timeline IDs)
+    srand48(static_cast<unsigned int>(systemTime()));
+}
+
+CommonTimeServer::~CommonTimeServer() {
+    shutdownThread();
+
+    // No need to grab the lock here.  We are in the destructor; if the the user
+    // has a thread in any of the APIs while the destructor is being called,
+    // there is a threading problem a the application level we cannot reasonably
+    // do anything about.
+    cleanupSocket_l();
+
+    if (mWakeupThreadFD >= 0) {
+        close(mWakeupThreadFD);
+        mWakeupThreadFD = -1;
+    }
+}
+
+bool CommonTimeServer::startServices() {
+    // start the ICommonClock service
+    mICommonClock = CommonClockService::instantiate(*this);
+    if (mICommonClock == NULL)
+        return false;
+
+    // start the ICommonTimeConfig service
+    mICommonTimeConfig = CommonTimeConfigService::instantiate(*this);
+    if (mICommonTimeConfig == NULL)
+        return false;
+
+    return true;
+}
+
+bool CommonTimeServer::threadLoop() {
+    // Register our service interfaces.
+    if (!startServices())
+        return false;
+
+    // Hold the lock while we are in the main thread loop.  It will release the
+    // lock when it blocks, and hold the lock at all other times.
+    mLock.lock();
+    runStateMachine_l();
+    mLock.unlock();
+
+    IPCThreadState::self()->stopProcess();
+    return false;
+}
+
+bool CommonTimeServer::runStateMachine_l() {
+    if (!mLocalClock.initCheck())
+        return false;
+
+    if (!mCommonClock.init(mLocalClock.getLocalFreq()))
+        return false;
+
+    // Enter the initial state.
+    becomeInitial("startup");
+
+    // run the state machine
+    while (!exitPending()) {
+        struct pollfd pfds[2];
+        int rc, timeout;
+        int eventCnt = 0;
+        int64_t wakeupTime;
+        uint32_t t1, t2;
+        bool needHandleTimeout = false;
+
+        // We are always interested in our wakeup FD.
+        pfds[eventCnt].fd      = mWakeupThreadFD;
+        pfds[eventCnt].events  = POLLIN;
+        pfds[eventCnt].revents = 0;
+        eventCnt++;
+
+        // If we have a valid socket, then we are interested in what it has to
+        // say as well.
+        if (mSocket >= 0) {
+            pfds[eventCnt].fd      = mSocket;
+            pfds[eventCnt].events  = POLLIN;
+            pfds[eventCnt].revents = 0;
+            eventCnt++;
+        }
+
+        t1 = static_cast<uint32_t>(mCurTimeout.msecTillTimeout());
+        t2 = static_cast<uint32_t>(mClockRecovery.applyRateLimitedSlew());
+        timeout = static_cast<int>(t1 < t2 ? t1 : t2);
+
+        // Note, we were holding mLock when this function was called.  We
+        // release it only while we are blocking and hold it at all other times.
+        mLock.unlock();
+        rc          = poll(pfds, eventCnt, timeout);
+        wakeupTime  = mLocalClock.getLocalTime();
+        mLock.lock();
+
+        // Is it time to shutdown?  If so, don't hesitate... just do it.
+        if (exitPending())
+            break;
+
+        // Did the poll fail?  This should never happen and is fatal if it does.
+        if (rc < 0) {
+            ALOGE("%s:%d poll failed", __PRETTY_FUNCTION__, __LINE__);
+            return false;
+        }
+
+        if (rc == 0) {
+            needHandleTimeout = !mCurTimeout.msecTillTimeout();
+            if (needHandleTimeout)
+                mCurTimeout.setTimeout(kInfiniteTimeout);
+        }
+
+        // Were we woken up on purpose?  If so, clear the eventfd with a read.
+        if (pfds[0].revents)
+            clearPendingWakeupEvents_l();
+
+        // Is out bind address dirty?  If so, clean up our socket (if any).
+        // Alternatively, do we have an active socket but should be auto
+        // disabled?  If so, release the socket and enter the proper sync state.
+        bool droppedSocket = false;
+        if (mBindIfaceDirty || ((mSocket >= 0) && shouldAutoDisable())) {
+            cleanupSocket_l();
+            mBindIfaceDirty = false;
+            droppedSocket = true;
+        }
+
+        // Do we not have a socket but should have one?  If so, try to set one
+        // up.
+        if ((mSocket < 0) && mBindIfaceValid && !shouldAutoDisable()) {
+            if (setupSocket_l()) {
+                // Success!  We are now joining a new network (either coming
+                // from no network, or coming from a potentially different
+                // network).  Force our priority to be lower so that we defer to
+                // any other masters which may already be on the network we are
+                // joining.  Later, when we enter either the client or the
+                // master state, we will clear this flag and go back to our
+                // normal election priority.
+                setForceLowPriority(true);
+                switch (mState) {
+                    // If we were in initial (whether we had a immediately
+                    // before this network or not) we want to simply reset the
+                    // system and start again.  Forcing a transition from
+                    // INITIAL to INITIAL should do the job.
+                    case CommonClockService::STATE_INITIAL:
+                        becomeInitial("bound interface");
+                        break;
+
+                    // If we were in the master state, then either we were the
+                    // master in a no-network situation, or we were the master
+                    // of a different network and have moved to a new interface.
+                    // In either case, immediately transition to Ronin at low
+                    // priority.  If there is no one in the network we just
+                    // joined, we will become master soon enough.  If there is,
+                    // we want to be certain to defer master status to the
+                    // existing timeline currently running on the network.
+                    //
+                    case CommonClockService::STATE_MASTER:
+                        becomeRonin("leaving networkless mode");
+                        break;
+
+                    // If we were in any other state (CLIENT, RONIN, or
+                    // WAIT_FOR_ELECTION) then we must be moving from one
+                    // network to another.  We have lost our old master;
+                    // transition to RONIN in an attempt to find a new master.
+                    // If there are none out there, we will just assume
+                    // responsibility for the timeline we used to be a client
+                    // of.
+                    default:
+                        becomeRonin("bound interface");
+                        break;
+                }
+            } else {
+                // That's odd... we failed to set up our socket.  This could be
+                // due to some transient network change which will work itself
+                // out shortly; schedule a retry attempt in the near future.
+                mCurTimeout.setTimeout(kSetupRetryTimeoutMs);
+            }
+
+            // One way or the other, we don't have any data to process at this
+            // point (since we just tried to bulid a new socket).  Loop back
+            // around and wait for the next thing to do.
+            continue;
+        } else if (droppedSocket) {
+            // We just lost our socket, and for whatever reason (either no
+            // config, or auto disable engaged) we are not supposed to rebuild
+            // one at this time.  We are not going to rebuild our socket until
+            // something about our config/auto-disabled status changes, so we
+            // are basically in network-less mode.  If we are already in either
+            // INITIAL or MASTER, just stay there until something changes.  If
+            // we are in any other state (CLIENT, RONIN or WAIT_FOR_ELECTION),
+            // then transition to either INITIAL or MASTER depending on whether
+            // or not our timeline is valid.
+            mStateChangeLog.log(ANDROID_LOG_INFO, LOG_TAG,
+                    "Entering networkless mode interface is %s, "
+                    "shouldAutoDisable = %s",
+                    mBindIfaceValid ? "valid" : "invalid",
+                    shouldAutoDisable() ? "true" : "false");
+            if ((mState != ICommonClock::STATE_INITIAL) &&
+                (mState != ICommonClock::STATE_MASTER)) {
+                if (mTimelineID == ICommonClock::kInvalidTimelineID)
+                    becomeInitial("network-less mode");
+                else
+                    becomeMaster("network-less mode");
+            }
+
+            continue;
+        }
+
+        // Time to handle the timeouts?
+        if (needHandleTimeout) {
+            if (!handleTimeout())
+                ALOGE("handleTimeout failed");
+            continue;
+        }
+
+        // Does our socket have data for us (assuming we still have one, we
+        // may have RXed a packet at the same time as a config change telling us
+        // to shut our socket down)?  If so, process its data.
+        if ((mSocket >= 0) && (eventCnt > 1) && (pfds[1].revents)) {
+            mLastPacketRxLocalTime = wakeupTime;
+            if (!handlePacket())
+                ALOGE("handlePacket failed");
+        }
+    }
+
+    cleanupSocket_l();
+    return true;
+}
+
+void CommonTimeServer::clearPendingWakeupEvents_l() {
+    int64_t tmp;
+    read(mWakeupThreadFD, &tmp, sizeof(tmp));
+}
+
+void CommonTimeServer::wakeupThread_l() {
+    int64_t tmp = 1;
+    write(mWakeupThreadFD, &tmp, sizeof(tmp));
+}
+
+void CommonTimeServer::cleanupSocket_l() {
+    if (mSocket >= 0) {
+        close(mSocket);
+        mSocket = -1;
+    }
+}
+
+void CommonTimeServer::shutdownThread() {
+    // Flag the work thread for shutdown.
+    this->requestExit();
+
+    // Signal the thread in case its sleeping.
+    mLock.lock();
+    wakeupThread_l();
+    mLock.unlock();
+
+    // Wait for the thread to exit.
+    this->join();
+}
+
+bool CommonTimeServer::setupSocket_l() {
+    int rc;
+    bool ret_val = false;
+    struct sockaddr_in* ipv4_addr = NULL;
+    char masterElectionEPStr[64];
+    const int one = 1;
+
+    // This should never be needed, but if we happened to have an old socket
+    // lying around, be sure to not leak it before proceeding.
+    cleanupSocket_l();
+
+    // If we don't have a valid endpoint to bind to, then how did we get here in
+    // the first place?  Regardless, we know that we are going to fail to bind,
+    // so don't even try.
+    if (!mBindIfaceValid)
+        return false;
+
+    sockaddrToString(mMasterElectionEP, true, masterElectionEPStr,
+                     sizeof(masterElectionEPStr));
+    mStateChangeLog.log(ANDROID_LOG_INFO, LOG_TAG,
+                        "Building socket :: bind = %s master election = %s",
+                        mBindIface.string(), masterElectionEPStr);
+
+    // TODO: add proper support for IPv6.  Right now, we block IPv6 addresses at
+    // the configuration interface level.
+    if (AF_INET != mMasterElectionEP.ss_family) {
+        mStateChangeLog.log(ANDROID_LOG_WARN, LOG_TAG,
+                            "TODO: add proper IPv6 support");
+        goto bailout;
+    }
+
+    // open a UDP socket for the timeline serivce
+    mSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    if (mSocket < 0) {
+        mStateChangeLog.log(ANDROID_LOG_ERROR, LOG_TAG,
+                            "Failed to create socket (errno = %d)", errno);
+        goto bailout;
+    }
+
+    // Bind to the selected interface using Linux's spiffy SO_BINDTODEVICE.
+    struct ifreq ifr;
+    memset(&ifr, 0, sizeof(ifr));
+    snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", mBindIface.string());
+    ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = 0;
+    rc = setsockopt(mSocket, SOL_SOCKET, SO_BINDTODEVICE,
+                    (void *)&ifr, sizeof(ifr));
+    if (rc) {
+        mStateChangeLog.log(ANDROID_LOG_ERROR, LOG_TAG,
+                            "Failed to bind socket at to interface %s "
+                            "(errno = %d)", ifr.ifr_name, errno);
+        goto bailout;
+    }
+
+    // Bind our socket to INADDR_ANY and the master election port.  The
+    // interface binding we made using SO_BINDTODEVICE should limit us to
+    // traffic only on the interface we are interested in.  We need to bind to
+    // INADDR_ANY and the specific master election port in order to be able to
+    // receive both unicast traffic and master election multicast traffic with
+    // just a single socket.
+    struct sockaddr_in bindAddr;
+    ipv4_addr = reinterpret_cast<struct sockaddr_in*>(&mMasterElectionEP);
+    memcpy(&bindAddr, ipv4_addr, sizeof(bindAddr));
+    bindAddr.sin_addr.s_addr = INADDR_ANY;
+    rc = bind(mSocket,
+              reinterpret_cast<const sockaddr *>(&bindAddr),
+              sizeof(bindAddr));
+    if (rc) {
+        mStateChangeLog.log(ANDROID_LOG_ERROR, LOG_TAG,
+                            "Failed to bind socket to port %hu (errno = %d)",
+                            ntohs(bindAddr.sin_port), errno);
+        goto bailout;
+    }
+
+    if (0xE0000000 == (ntohl(ipv4_addr->sin_addr.s_addr) & 0xF0000000)) {
+        // If our master election endpoint is a multicast address, be sure to join
+        // the multicast group.
+        struct ip_mreq mreq;
+        mreq.imr_multiaddr = ipv4_addr->sin_addr;
+        mreq.imr_interface.s_addr = htonl(INADDR_ANY);
+        rc = setsockopt(mSocket, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+                        &mreq, sizeof(mreq));
+        if (rc == -1) {
+            ALOGE("Failed to join multicast group at %s.  (errno = %d)",
+                 masterElectionEPStr, errno);
+            goto bailout;
+        }
+
+        // disable loopback of multicast packets
+        const int zero = 0;
+        rc = setsockopt(mSocket, IPPROTO_IP, IP_MULTICAST_LOOP,
+                        &zero, sizeof(zero));
+        if (rc == -1) {
+            mStateChangeLog.log(ANDROID_LOG_ERROR, LOG_TAG,
+                                "Failed to disable multicast loopback "
+                                "(errno = %d)", errno);
+            goto bailout;
+        }
+    } else
+    if (ntohl(ipv4_addr->sin_addr.s_addr) == 0xFFFFFFFF) {
+        // If the master election address is the broadcast address, then enable
+        // the broadcast socket option
+        rc = setsockopt(mSocket, SOL_SOCKET, SO_BROADCAST, &one, sizeof(one));
+        if (rc == -1) {
+            mStateChangeLog.log(ANDROID_LOG_ERROR, LOG_TAG,
+                                "Failed to enable broadcast (errno = %d)",
+                                errno);
+            goto bailout;
+        }
+    } else {
+        // If the master election address is neither broadcast, nor multicast,
+        // then we are misconfigured.  The config API layer should prevent this
+        // from ever happening.
+        goto bailout;
+    }
+
+    // Set the TTL of sent packets to 1.  (Time protocol sync should never leave
+    // the local subnet)
+    rc = setsockopt(mSocket, IPPROTO_IP, IP_TTL, &one, sizeof(one));
+    if (rc == -1) {
+        mStateChangeLog.log(ANDROID_LOG_ERROR, LOG_TAG,
+                            "Failed to set TTL to %d (errno = %d)", one, errno);
+        goto bailout;
+    }
+
+    // get the device's unique ID
+    if (!assignDeviceID())
+        goto bailout;
+
+    ret_val = true;
+
+bailout:
+    if (!ret_val)
+        cleanupSocket_l();
+    return ret_val;
+}
+
+// generate a unique device ID that can be used for arbitration
+bool CommonTimeServer::assignDeviceID() {
+    if (!mBindIfaceValid)
+        return false;
+
+    struct ifreq ifr;
+    memset(&ifr, 0, sizeof(ifr));
+    ifr.ifr_addr.sa_family = AF_INET;
+    strlcpy(ifr.ifr_name, mBindIface.string(), IFNAMSIZ);
+
+    int rc = ioctl(mSocket, SIOCGIFHWADDR, &ifr);
+    if (rc) {
+        ALOGE("%s:%d ioctl failed", __PRETTY_FUNCTION__, __LINE__);
+        return false;
+    }
+
+    if (ifr.ifr_addr.sa_family != ARPHRD_ETHER) {
+        ALOGE("%s:%d got non-Ethernet address", __PRETTY_FUNCTION__, __LINE__);
+        return false;
+    }
+
+    mDeviceID = 0;
+    for (int i = 0; i < ETH_ALEN; i++) {
+        mDeviceID = (mDeviceID << 8) | ifr.ifr_hwaddr.sa_data[i];
+    }
+
+    return true;
+}
+
+// generate a new timeline ID
+void CommonTimeServer::assignTimelineID() {
+    do {
+        mTimelineID = (static_cast<uint64_t>(lrand48()) << 32)
+                    |  static_cast<uint64_t>(lrand48());
+    } while (mTimelineID == ICommonClock::kInvalidTimelineID);
+}
+
+// Select a preference between the device IDs of two potential masters.
+// Returns true if the first ID wins, or false if the second ID wins.
+bool CommonTimeServer::arbitrateMaster(
+        uint64_t deviceID1, uint8_t devicePrio1,
+        uint64_t deviceID2, uint8_t devicePrio2) {
+    return ((devicePrio1 >  devicePrio2) ||
+           ((devicePrio1 == devicePrio2) && (deviceID1 > deviceID2)));
+}
+
+static void hexDumpToString(const uint8_t* src, size_t src_len,
+                            char* dst, size_t dst_len) {
+    size_t offset = 0;
+    size_t i;
+
+    for (i = 0; (i < src_len) && (offset < dst_len); ++i) {
+        int res;
+        if (0 == (i % 16)) {
+            res = snprintf(dst + offset, dst_len - offset, "\n%04x :", i);
+            if (res < 0)
+                break;
+            offset += res;
+            if (offset >= dst_len)
+                break;
+        }
+
+        res = snprintf(dst + offset, dst_len - offset, " %02x", src[i]);
+        if (res < 0)
+            break;
+        offset += res;
+    }
+
+    dst[dst_len - 1] = 0;
+}
+
+bool CommonTimeServer::handlePacket() {
+    uint8_t buf[256];
+    struct sockaddr_storage srcAddr;
+    socklen_t srcAddrLen = sizeof(srcAddr);
+
+    ssize_t recvBytes = recvfrom(
+            mSocket, buf, sizeof(buf), 0,
+            reinterpret_cast<const sockaddr *>(&srcAddr), &srcAddrLen);
+
+    if (recvBytes < 0) {
+        mBadPktLog.log(ANDROID_LOG_ERROR, LOG_TAG,
+                       "recvfrom failed (res %d, errno %d)",
+                       recvBytes, errno);
+        return false;
+    }
+
+    UniversalTimeServicePacket pkt;
+    if (pkt.deserializePacket(buf, recvBytes, mSyncGroupID) < 0) {
+        char hex[256];
+        char srcEPStr[64];
+
+        hexDumpToString(buf, static_cast<size_t>(recvBytes), hex, sizeof(hex));
+        sockaddrToString(srcAddr, true, srcEPStr, sizeof(srcEPStr));
+
+        mBadPktLog.log("Failed to parse %d byte packet from %s.%s",
+                       recvBytes, srcEPStr, hex);
+        return false;
+    }
+
+    bool result;
+    switch (pkt.packetType) {
+        case TIME_PACKET_WHO_IS_MASTER_REQUEST:
+            result = handleWhoIsMasterRequest(&pkt.p.who_is_master_request,
+                                              srcAddr);
+            break;
+
+        case TIME_PACKET_WHO_IS_MASTER_RESPONSE:
+            result = handleWhoIsMasterResponse(&pkt.p.who_is_master_response,
+                                               srcAddr);
+            break;
+
+        case TIME_PACKET_SYNC_REQUEST:
+            result = handleSyncRequest(&pkt.p.sync_request, srcAddr);
+            break;
+
+        case TIME_PACKET_SYNC_RESPONSE:
+            result = handleSyncResponse(&pkt.p.sync_response, srcAddr);
+            break;
+
+        case TIME_PACKET_MASTER_ANNOUNCEMENT:
+            result = handleMasterAnnouncement(&pkt.p.master_announcement,
+                                              srcAddr);
+            break;
+
+        default: {
+            char srcEPStr[64];
+            sockaddrToString(srcAddr, true, srcEPStr, sizeof(srcEPStr));
+
+            mBadPktLog.log(ANDROID_LOG_WARN, LOG_TAG,
+                           "unknown packet type (%d) from %s",
+                           pkt.packetType, srcEPStr);
+
+            result = false;
+        } break;
+    }
+
+    return result;
+}
+
+bool CommonTimeServer::handleTimeout() {
+    // If we have no socket, then this must be a timeout to retry socket setup.
+    if (mSocket < 0)
+        return true;
+
+    switch (mState) {
+        case ICommonClock::STATE_INITIAL:
+            return handleTimeoutInitial();
+        case ICommonClock::STATE_CLIENT:
+            return handleTimeoutClient();
+        case ICommonClock::STATE_MASTER:
+            return handleTimeoutMaster();
+        case ICommonClock::STATE_RONIN:
+            return handleTimeoutRonin();
+        case ICommonClock::STATE_WAIT_FOR_ELECTION:
+            return handleTimeoutWaitForElection();
+    }
+
+    return false;
+}
+
+bool CommonTimeServer::handleTimeoutInitial() {
+    if (++mInitial_WhoIsMasterRequestTimeouts ==
+            kInitial_NumWhoIsMasterRetries) {
+        // none of our attempts to discover a master succeeded, so make
+        // this device the master
+        return becomeMaster("initial timeout");
+    } else {
+        // retry the WhoIsMaster request
+        return sendWhoIsMasterRequest();
+    }
+}
+
+bool CommonTimeServer::handleTimeoutClient() {
+    if (shouldPanicNotGettingGoodData())
+        return becomeInitial("timeout panic, no good data");
+
+    if (mClient_SyncRequestPending) {
+        mClient_SyncRequestPending = false;
+
+        if (++mClient_SyncRequestTimeouts < kClient_NumSyncRequestRetries) {
+            // a sync request has timed out, so retry
+            return sendSyncRequest();
+        } else {
+            // The master has failed to respond to a sync request for too many
+            // times in a row.  Assume the master is dead and start electing
+            // a new master.
+            return becomeRonin("master not responding");
+        }
+    } else {
+        // initiate the next sync request
+        return sendSyncRequest();
+    }
+}
+
+bool CommonTimeServer::handleTimeoutMaster() {
+    // send another announcement from the master
+    return sendMasterAnnouncement();
+}
+
+bool CommonTimeServer::handleTimeoutRonin() {
+    if (++mRonin_WhoIsMasterRequestTimeouts == kRonin_NumWhoIsMasterRetries) {
+        // no other master is out there, so we won the election
+        return becomeMaster("no better masters detected");
+    } else {
+        return sendWhoIsMasterRequest();
+    }
+}
+
+bool CommonTimeServer::handleTimeoutWaitForElection() {
+    return becomeRonin("timeout waiting for election conclusion");
+}
+
+bool CommonTimeServer::handleWhoIsMasterRequest(
+        const WhoIsMasterRequestPacket* request,
+        const sockaddr_storage& srcAddr) {
+    // Skip our own messages which come back via broadcast loopback.
+    if (request->senderDeviceID == mDeviceID)
+        return true;
+
+    char srcEPStr[64];
+    sockaddrToString(srcAddr, true, srcEPStr, sizeof(srcEPStr));
+    mElectionLog.log("RXed WhoIs master request while in state %s.  "
+                     "src %s reqTID %016llx ourTID %016llx",
+                     stateToString(mState), srcEPStr,
+                     request->timelineID, mTimelineID);
+
+    if (mState == ICommonClock::STATE_MASTER) {
+        // is this request related to this master's timeline?
+        if (request->timelineID != ICommonClock::kInvalidTimelineID &&
+            request->timelineID != mTimelineID)
+            return true;
+
+        WhoIsMasterResponsePacket pkt;
+        pkt.initHeader(mTimelineID, mSyncGroupID);
+        pkt.deviceID = mDeviceID;
+        pkt.devicePriority = effectivePriority();
+
+        mElectionLog.log("TXing WhoIs master resp to %s while in state %s.  "
+                         "ourTID %016llx ourGID %016llx ourDID %016llx "
+                         "ourPrio %u",
+                         srcEPStr, stateToString(mState),
+                         mTimelineID, mSyncGroupID,
+                         pkt.deviceID, pkt.devicePriority);
+
+        uint8_t buf[256];
+        ssize_t bufSz = pkt.serializePacket(buf, sizeof(buf));
+        if (bufSz < 0)
+            return false;
+
+        ssize_t sendBytes = sendto(
+                mSocket, buf, bufSz, 0,
+                reinterpret_cast<const sockaddr *>(&srcAddr),
+                sizeof(srcAddr));
+        if (sendBytes == -1) {
+            ALOGE("%s:%d sendto failed", __PRETTY_FUNCTION__, __LINE__);
+            return false;
+        }
+    } else if (mState == ICommonClock::STATE_RONIN) {
+        // if we hear a WhoIsMaster request from another device following
+        // the same timeline and that device wins arbitration, then we will stop
+        // trying to elect ourselves master and will instead wait for an
+        // announcement from the election winner
+        if (request->timelineID != mTimelineID)
+            return true;
+
+        if (arbitrateMaster(request->senderDeviceID,
+                            request->senderDevicePriority,
+                            mDeviceID,
+                            effectivePriority()))
+            return becomeWaitForElection("would lose election");
+
+        return true;
+    } else if (mState == ICommonClock::STATE_INITIAL) {
+        // If a group of devices booted simultaneously (e.g. after a power
+        // outage) and all of them are in the initial state and there is no
+        // master, then each device may time out and declare itself master at
+        // the same time.  To avoid this, listen for
+        // WhoIsMaster(InvalidTimeline) requests from peers.  If we would lose
+        // arbitration against that peer, reset our timeout count so that the
+        // peer has a chance to become master before we time out.
+        if (request->timelineID == ICommonClock::kInvalidTimelineID &&
+                arbitrateMaster(request->senderDeviceID,
+                                request->senderDevicePriority,
+                                mDeviceID,
+                                effectivePriority())) {
+            mInitial_WhoIsMasterRequestTimeouts = 0;
+        }
+    }
+
+    return true;
+}
+
+bool CommonTimeServer::handleWhoIsMasterResponse(
+        const WhoIsMasterResponsePacket* response,
+        const sockaddr_storage& srcAddr) {
+    // Skip our own messages which come back via broadcast loopback.
+    if (response->deviceID == mDeviceID)
+        return true;
+
+    char srcEPStr[64];
+    sockaddrToString(srcAddr, true, srcEPStr, sizeof(srcEPStr));
+    mElectionLog.log("RXed WhoIs master response while in state %s.  "
+                     "src %s respTID %016llx respDID %016llx respPrio %u "
+                     "ourTID %016llx",
+                     stateToString(mState), srcEPStr,
+                     response->timelineID,
+                     response->deviceID,
+                     static_cast<uint32_t>(response->devicePriority),
+                     mTimelineID);
+
+    if (mState == ICommonClock::STATE_INITIAL || mState == ICommonClock::STATE_RONIN) {
+        return becomeClient(srcAddr,
+                            response->deviceID,
+                            response->devicePriority,
+                            response->timelineID,
+                            "heard whois response");
+    } else if (mState == ICommonClock::STATE_CLIENT) {
+        // if we get multiple responses because there are multiple devices
+        // who believe that they are master, then follow the master that
+        // wins arbitration
+        if (arbitrateMaster(response->deviceID,
+                            response->devicePriority,
+                            mClient_MasterDeviceID,
+                            mClient_MasterDevicePriority)) {
+            return becomeClient(srcAddr,
+                                response->deviceID,
+                                response->devicePriority,
+                                response->timelineID,
+                                "heard whois response");
+        }
+    }
+
+    return true;
+}
+
+bool CommonTimeServer::handleSyncRequest(const SyncRequestPacket* request,
+                                         const sockaddr_storage& srcAddr) {
+    SyncResponsePacket pkt;
+    pkt.initHeader(mTimelineID, mSyncGroupID);
+
+    if ((mState == ICommonClock::STATE_MASTER) &&
+        (mTimelineID == request->timelineID)) {
+        int64_t rxLocalTime = mLastPacketRxLocalTime;
+        int64_t rxCommonTime;
+
+        // If we are master on an actual network and have actual clients, then
+        // we are no longer low priority.
+        setForceLowPriority(false);
+
+        if (OK != mCommonClock.localToCommon(rxLocalTime, &rxCommonTime)) {
+            return false;
+        }
+
+        int64_t txLocalTime = mLocalClock.getLocalTime();;
+        int64_t txCommonTime;
+        if (OK != mCommonClock.localToCommon(txLocalTime, &txCommonTime)) {
+            return false;
+        }
+
+        pkt.nak = 0;
+        pkt.clientTxLocalTime  = request->clientTxLocalTime;
+        pkt.masterRxCommonTime = rxCommonTime;
+        pkt.masterTxCommonTime = txCommonTime;
+    } else {
+        pkt.nak = 1;
+        pkt.clientTxLocalTime  = 0;
+        pkt.masterRxCommonTime = 0;
+        pkt.masterTxCommonTime = 0;
+    }
+
+    uint8_t buf[256];
+    ssize_t bufSz = pkt.serializePacket(buf, sizeof(buf));
+    if (bufSz < 0)
+        return false;
+
+    ssize_t sendBytes = sendto(
+            mSocket, &buf, bufSz, 0,
+            reinterpret_cast<const sockaddr *>(&srcAddr),
+            sizeof(srcAddr));
+    if (sendBytes == -1) {
+        ALOGE("%s:%d sendto failed", __PRETTY_FUNCTION__, __LINE__);
+        return false;
+    }
+
+    return true;
+}
+
+bool CommonTimeServer::handleSyncResponse(
+        const SyncResponsePacket* response,
+        const sockaddr_storage& srcAddr) {
+    if (mState != ICommonClock::STATE_CLIENT)
+        return true;
+
+    assert(mMasterEPValid);
+    if (!sockaddrMatch(srcAddr, mMasterEP, true)) {
+        char srcEP[64], expectedEP[64];
+        sockaddrToString(srcAddr, true, srcEP, sizeof(srcEP));
+        sockaddrToString(mMasterEP, true, expectedEP, sizeof(expectedEP));
+        ALOGI("Dropping sync response from unexpected address."
+             " Expected %s Got %s", expectedEP, srcEP);
+        return true;
+    }
+
+    if (response->nak) {
+        // if our master is no longer accepting requests, then we need to find
+        // a new master
+        return becomeRonin("master NAK'ed");
+    }
+
+    mClient_SyncRequestPending = 0;
+    mClient_SyncRequestTimeouts = 0;
+    mClient_PacketRTTLog.logRX(response->clientTxLocalTime,
+                               mLastPacketRxLocalTime);
+
+    bool result;
+    if (!(mClient_SyncRespsRXedFromCurMaster++)) {
+        // the first request/response exchange between a client and a master
+        // may take unusually long due to ARP, so discard it.
+        result = true;
+    } else {
+        int64_t clientTxLocalTime  = response->clientTxLocalTime;
+        int64_t clientRxLocalTime  = mLastPacketRxLocalTime;
+        int64_t masterTxCommonTime = response->masterTxCommonTime;
+        int64_t masterRxCommonTime = response->masterRxCommonTime;
+
+        int64_t rtt       = (clientRxLocalTime - clientTxLocalTime);
+        int64_t avgLocal  = (clientTxLocalTime + clientRxLocalTime) >> 1;
+        int64_t avgCommon = (masterTxCommonTime + masterRxCommonTime) >> 1;
+
+        // if the RTT of the packet is significantly larger than the panic
+        // threshold, we should simply discard it.  Its better to do nothing
+        // than to take cues from a packet like that.
+        int rttCommon = mCommonClock.localDurationToCommonDuration(rtt);
+        if (rttCommon > (static_cast<int64_t>(mPanicThresholdUsec) * 
+                         kRTTDiscardPanicThreshMultiplier)) {
+            ALOGV("Dropping sync response with RTT of %lld uSec", rttCommon);
+            mClient_ExpiredSyncRespsRXedFromCurMaster++;
+            if (shouldPanicNotGettingGoodData())
+                return becomeInitial("RX panic, no good data");
+        } else {
+            result = mClockRecovery.pushDisciplineEvent(avgLocal, avgCommon, rttCommon);
+            mClient_LastGoodSyncRX = clientRxLocalTime;
+
+            if (result) {
+                // indicate to listeners that we've synced to the common timeline
+                notifyClockSync();
+            } else {
+                ALOGE("Panic!  Observed clock sync error is too high to tolerate,"
+                        " resetting state machine and starting over.");
+                notifyClockSyncLoss();
+                return becomeInitial("panic");
+            }
+        }
+    }
+
+    mCurTimeout.setTimeout(mSyncRequestIntervalMs);
+    return result;
+}
+
+bool CommonTimeServer::handleMasterAnnouncement(
+        const MasterAnnouncementPacket* packet,
+        const sockaddr_storage& srcAddr) {
+    uint64_t newDeviceID   = packet->deviceID;
+    uint8_t  newDevicePrio = packet->devicePriority;
+    uint64_t newTimelineID = packet->timelineID;
+
+    // Skip our own messages which come back via broadcast loopback.
+    if (newDeviceID == mDeviceID)
+        return true;
+
+    char srcEPStr[64];
+    sockaddrToString(srcAddr, true, srcEPStr, sizeof(srcEPStr));
+    mElectionLog.log("RXed master announcement while in state %s.  "
+                     "src %s srcDevID %lld srcPrio %u srcTID %016llx",
+                     stateToString(mState), srcEPStr,
+                     newDeviceID, static_cast<uint32_t>(newDevicePrio),
+                     newTimelineID);
+
+    if (mState == ICommonClock::STATE_INITIAL ||
+        mState == ICommonClock::STATE_RONIN ||
+        mState == ICommonClock::STATE_WAIT_FOR_ELECTION) {
+        // if we aren't currently following a master, then start following
+        // this new master
+        return becomeClient(srcAddr,
+                            newDeviceID,
+                            newDevicePrio,
+                            newTimelineID,
+                            "heard master announcement");
+    } else if (mState == ICommonClock::STATE_CLIENT) {
+        // if the new master wins arbitration against our current master,
+        // then become a client of the new master
+        if (arbitrateMaster(newDeviceID,
+                            newDevicePrio,
+                            mClient_MasterDeviceID,
+                            mClient_MasterDevicePriority))
+            return becomeClient(srcAddr,
+                                newDeviceID,
+                                newDevicePrio,
+                                newTimelineID,
+                                "heard master announcement");
+    } else if (mState == ICommonClock::STATE_MASTER) {
+        // two masters are competing - if the new one wins arbitration, then
+        // cease acting as master
+        if (arbitrateMaster(newDeviceID, newDevicePrio,
+                            mDeviceID, effectivePriority()))
+            return becomeClient(srcAddr, newDeviceID,
+                                newDevicePrio, newTimelineID,
+                                "heard master announcement");
+    }
+
+    return true;
+}
+
+bool CommonTimeServer::sendWhoIsMasterRequest() {
+    assert(mState == ICommonClock::STATE_INITIAL || mState == ICommonClock::STATE_RONIN);
+
+    // If we have no socket, then we must be in the unconfigured initial state.
+    // Don't report any errors, just don't try to send the initial who-is-master
+    // query.  Eventually, our network will either become configured, or we will
+    // be forced into network-less master mode by higher level code.
+    if (mSocket < 0) {
+        assert(mState == ICommonClock::STATE_INITIAL);
+        return true;
+    }
+
+    bool ret = false;
+    WhoIsMasterRequestPacket pkt;
+    pkt.initHeader(mSyncGroupID);
+    pkt.senderDeviceID = mDeviceID;
+    pkt.senderDevicePriority = effectivePriority();
+
+    uint8_t buf[256];
+    ssize_t bufSz = pkt.serializePacket(buf, sizeof(buf));
+    if (bufSz >= 0) {
+        char dstEPStr[64];
+        sockaddrToString(mMasterElectionEP, true, dstEPStr, sizeof(dstEPStr));
+        mElectionLog.log("TXing WhoIs master request to %s while in state %s.  "
+                         "ourTID %016llx ourGID %016llx ourDID %016llx "
+                         "ourPrio %u",
+                         dstEPStr, stateToString(mState),
+                         mTimelineID, mSyncGroupID,
+                         pkt.senderDeviceID, pkt.senderDevicePriority);
+
+        ssize_t sendBytes = sendto(
+                mSocket, buf, bufSz, 0,
+                reinterpret_cast<const sockaddr *>(&mMasterElectionEP),
+                sizeof(mMasterElectionEP));
+        if (sendBytes < 0)
+            ALOGE("WhoIsMaster sendto failed (errno %d)", errno);
+        ret = true;
+    }
+
+    if (mState == ICommonClock::STATE_INITIAL) {
+        mCurTimeout.setTimeout(kInitial_WhoIsMasterTimeoutMs);
+    } else {
+        mCurTimeout.setTimeout(kRonin_WhoIsMasterTimeoutMs);
+    }
+
+    return ret;
+}
+
+bool CommonTimeServer::sendSyncRequest() {
+    // If we are sending sync requests, then we must be in the client state and
+    // we must have a socket (when we have no network, we are only supposed to
+    // be in INITIAL or MASTER)
+    assert(mState == ICommonClock::STATE_CLIENT);
+    assert(mSocket >= 0);
+
+    bool ret = false;
+    SyncRequestPacket pkt;
+    pkt.initHeader(mTimelineID, mSyncGroupID);
+    pkt.clientTxLocalTime = mLocalClock.getLocalTime();
+
+    if (!mClient_FirstSyncTX)
+        mClient_FirstSyncTX = pkt.clientTxLocalTime;
+
+    mClient_PacketRTTLog.logTX(pkt.clientTxLocalTime);
+
+    uint8_t buf[256];
+    ssize_t bufSz = pkt.serializePacket(buf, sizeof(buf));
+    if (bufSz >= 0) {
+        ssize_t sendBytes = sendto(
+                mSocket, buf, bufSz, 0,
+                reinterpret_cast<const sockaddr *>(&mMasterEP),
+                sizeof(mMasterEP));
+        if (sendBytes < 0)
+            ALOGE("SyncRequest sendto failed (errno %d)", errno);
+        ret = true;
+    }
+
+    mClient_SyncsSentToCurMaster++;
+    mCurTimeout.setTimeout(mSyncRequestIntervalMs);
+    mClient_SyncRequestPending = true;
+
+    return ret;
+}
+
+bool CommonTimeServer::sendMasterAnnouncement() {
+    bool ret = false;
+    assert(mState == ICommonClock::STATE_MASTER);
+
+    // If we are being asked to send a master announcement, but we have no
+    // socket, we must be in network-less master mode.  Don't bother to send the
+    // announcement, and don't bother to schedule a timeout.  When the network
+    // comes up, the work thread will get poked and start the process of
+    // figuring out who the current master should be.
+    if (mSocket < 0) {
+        mCurTimeout.setTimeout(kInfiniteTimeout);
+        return true;
+    }
+
+    MasterAnnouncementPacket pkt;
+    pkt.initHeader(mTimelineID, mSyncGroupID);
+    pkt.deviceID = mDeviceID;
+    pkt.devicePriority = effectivePriority();
+
+    uint8_t buf[256];
+    ssize_t bufSz = pkt.serializePacket(buf, sizeof(buf));
+    if (bufSz >= 0) {
+        char dstEPStr[64];
+        sockaddrToString(mMasterElectionEP, true, dstEPStr, sizeof(dstEPStr));
+        mElectionLog.log("TXing Master announcement to %s while in state %s.  "
+                         "ourTID %016llx ourGID %016llx ourDID %016llx "
+                         "ourPrio %u",
+                         dstEPStr, stateToString(mState),
+                         mTimelineID, mSyncGroupID,
+                         pkt.deviceID, pkt.devicePriority);
+
+        ssize_t sendBytes = sendto(
+                mSocket, buf, bufSz, 0,
+                reinterpret_cast<const sockaddr *>(&mMasterElectionEP),
+                sizeof(mMasterElectionEP));
+        if (sendBytes < 0)
+            ALOGE("MasterAnnouncement sendto failed (errno %d)", errno);
+        ret = true;
+    }
+
+    mCurTimeout.setTimeout(mMasterAnnounceIntervalMs);
+    return ret;
+}
+
+bool CommonTimeServer::becomeClient(const sockaddr_storage& masterEP,
+                                    uint64_t masterDeviceID,
+                                    uint8_t  masterDevicePriority,
+                                    uint64_t timelineID,
+                                    const char* cause) {
+    char newEPStr[64], oldEPStr[64];
+    sockaddrToString(masterEP, true, newEPStr, sizeof(newEPStr));
+    sockaddrToString(mMasterEP, mMasterEPValid, oldEPStr, sizeof(oldEPStr));
+
+    mStateChangeLog.log(ANDROID_LOG_INFO, LOG_TAG,
+            "%s --> CLIENT (%s) :%s"
+            " OldMaster: %02x-%014llx::%016llx::%s"
+            " NewMaster: %02x-%014llx::%016llx::%s",
+            stateToString(mState), cause,
+            (mTimelineID != timelineID) ? " (new timeline)" : "",
+            mClient_MasterDevicePriority, mClient_MasterDeviceID,
+            mTimelineID, oldEPStr,
+            masterDevicePriority, masterDeviceID,
+            timelineID, newEPStr);
+
+    if (mTimelineID != timelineID) {
+        // start following a new timeline
+        mTimelineID = timelineID;
+        mClockRecovery.reset(true, true);
+        notifyClockSyncLoss();
+    } else {
+        // start following a new master on the existing timeline
+        mClockRecovery.reset(false, true);
+    }
+
+    mMasterEP = masterEP;
+    mMasterEPValid = true;
+
+    // If we are on a real network as a client of a real master, then we should
+    // no longer force low priority.  If our master disappears, we should have
+    // the high priority bit set during the election to replace the master
+    // because this group was a real group and not a singleton created in
+    // networkless mode.
+    setForceLowPriority(false);
+
+    mClient_MasterDeviceID = masterDeviceID;
+    mClient_MasterDevicePriority = masterDevicePriority;
+    resetSyncStats();
+
+    setState(ICommonClock::STATE_CLIENT);
+
+    // add some jitter to when the various clients send their requests
+    // in order to reduce the likelihood that a group of clients overload
+    // the master after receiving a master announcement
+    usleep((lrand48() % 100) * 1000);
+
+    return sendSyncRequest();
+}
+
+bool CommonTimeServer::becomeMaster(const char* cause) {
+    uint64_t oldTimelineID = mTimelineID;
+    if (mTimelineID == ICommonClock::kInvalidTimelineID) {
+        // this device has not been following any existing timeline,
+        // so it will create a new timeline and declare itself master
+        assert(!mCommonClock.isValid());
+
+        // set the common time basis
+        mCommonClock.setBasis(mLocalClock.getLocalTime(), 0);
+
+        // assign an arbitrary timeline iD
+        assignTimelineID();
+
+        // notify listeners that we've created a common timeline
+        notifyClockSync();
+    }
+
+    mStateChangeLog.log(ANDROID_LOG_INFO, LOG_TAG,
+            "%s --> MASTER (%s) : %s timeline %016llx",
+            stateToString(mState), cause,
+            (oldTimelineID == mTimelineID) ? "taking ownership of"
+                                           : "creating new",
+            mTimelineID);
+
+    memset(&mMasterEP, 0, sizeof(mMasterEP));
+    mMasterEPValid = false;
+    mClient_MasterDevicePriority = effectivePriority();
+    mClient_MasterDeviceID = mDeviceID;
+    mClockRecovery.reset(false, true);
+    resetSyncStats();
+
+    setState(ICommonClock::STATE_MASTER);
+    return sendMasterAnnouncement();
+}
+
+bool CommonTimeServer::becomeRonin(const char* cause) {
+    // If we were the client of a given timeline, but had never received even a
+    // single time sync packet, then we transition back to Initial instead of
+    // Ronin.  If we transition to Ronin and end up becoming the new Master, we
+    // will be unable to service requests for other clients because we never
+    // actually knew what time it was.  By going to initial, we ensure that
+    // other clients who know what time it is, but would lose master arbitration
+    // in the Ronin case, will step up and become the proper new master of the
+    // old timeline.
+
+    char oldEPStr[64];
+    sockaddrToString(mMasterEP, mMasterEPValid, oldEPStr, sizeof(oldEPStr));
+    memset(&mMasterEP, 0, sizeof(mMasterEP));
+    mMasterEPValid = false;
+
+    if (mCommonClock.isValid()) {
+        mStateChangeLog.log(ANDROID_LOG_INFO, LOG_TAG,
+             "%s --> RONIN (%s) : lost track of previously valid timeline "
+             "%02x-%014llx::%016llx::%s (%d TXed %d RXed %d RXExpired)",
+             stateToString(mState), cause,
+             mClient_MasterDevicePriority, mClient_MasterDeviceID,
+             mTimelineID, oldEPStr,
+             mClient_SyncsSentToCurMaster,
+             mClient_SyncRespsRXedFromCurMaster,
+             mClient_ExpiredSyncRespsRXedFromCurMaster);
+
+        mRonin_WhoIsMasterRequestTimeouts = 0;
+        setState(ICommonClock::STATE_RONIN);
+        return sendWhoIsMasterRequest();
+    } else {
+        mStateChangeLog.log(ANDROID_LOG_INFO, LOG_TAG,
+             "%s --> INITIAL (%s) : never synced timeline "
+             "%02x-%014llx::%016llx::%s (%d TXed %d RXed %d RXExpired)",
+             stateToString(mState), cause,
+             mClient_MasterDevicePriority, mClient_MasterDeviceID,
+             mTimelineID, oldEPStr,
+             mClient_SyncsSentToCurMaster,
+             mClient_SyncRespsRXedFromCurMaster,
+             mClient_ExpiredSyncRespsRXedFromCurMaster);
+
+        return becomeInitial("ronin, no timeline");
+    }
+}
+
+bool CommonTimeServer::becomeWaitForElection(const char* cause) {
+    mStateChangeLog.log(ANDROID_LOG_INFO, LOG_TAG,
+         "%s --> WAIT_FOR_ELECTION (%s) : dropping out of election,"
+         " waiting %d mSec for completion.",
+         stateToString(mState), cause, kWaitForElection_TimeoutMs);
+
+    setState(ICommonClock::STATE_WAIT_FOR_ELECTION);
+    mCurTimeout.setTimeout(kWaitForElection_TimeoutMs);
+    return true;
+}
+
+bool CommonTimeServer::becomeInitial(const char* cause) {
+    mStateChangeLog.log(ANDROID_LOG_INFO, LOG_TAG,
+                        "Entering INITIAL (%s), total reset.",
+                        cause);
+
+    setState(ICommonClock::STATE_INITIAL);
+
+    // reset clock recovery
+    mClockRecovery.reset(true, true);
+
+    // reset internal state bookkeeping.
+    mCurTimeout.setTimeout(kInfiniteTimeout);
+    memset(&mMasterEP, 0, sizeof(mMasterEP));
+    mMasterEPValid = false;
+    mLastPacketRxLocalTime = 0;
+    mTimelineID = ICommonClock::kInvalidTimelineID;
+    mClockSynced = false;
+    mInitial_WhoIsMasterRequestTimeouts = 0;
+    mClient_MasterDeviceID = 0;
+    mClient_MasterDevicePriority = 0;
+    mRonin_WhoIsMasterRequestTimeouts = 0;
+    resetSyncStats();
+
+    // send the first request to discover the master
+    return sendWhoIsMasterRequest();
+}
+
+void CommonTimeServer::notifyClockSync() {
+    if (!mClockSynced) {
+        mClockSynced = true;
+        mICommonClock->notifyOnTimelineChanged(mTimelineID);
+    }
+}
+
+void CommonTimeServer::notifyClockSyncLoss() {
+    if (mClockSynced) {
+        mClockSynced = false;
+        mICommonClock->notifyOnTimelineChanged(
+                ICommonClock::kInvalidTimelineID);
+    }
+}
+
+void CommonTimeServer::setState(ICommonClock::State s) {
+    mState = s;
+}
+
+const char* CommonTimeServer::stateToString(ICommonClock::State s) {
+    switch(s) {
+        case ICommonClock::STATE_INITIAL:
+            return "INITIAL";
+        case ICommonClock::STATE_CLIENT:
+            return "CLIENT";
+        case ICommonClock::STATE_MASTER:
+            return "MASTER";
+        case ICommonClock::STATE_RONIN:
+            return "RONIN";
+        case ICommonClock::STATE_WAIT_FOR_ELECTION:
+            return "WAIT_FOR_ELECTION";
+        default:
+            return "unknown";
+    }
+}
+
+void CommonTimeServer::sockaddrToString(const sockaddr_storage& addr,
+                                        bool addrValid,
+                                        char* buf, size_t bufLen) {
+    if (!bufLen || !buf)
+        return;
+
+    if (addrValid) {
+        switch (addr.ss_family) {
+            case AF_INET: {
+                const struct sockaddr_in* sa =
+                    reinterpret_cast<const struct sockaddr_in*>(&addr);
+                unsigned long a = ntohl(sa->sin_addr.s_addr);
+                uint16_t      p = ntohs(sa->sin_port);
+                snprintf(buf, bufLen, "%lu.%lu.%lu.%lu:%hu",
+                        ((a >> 24) & 0xFF), ((a >> 16) & 0xFF),
+                        ((a >>  8) & 0xFF),  (a        & 0xFF), p);
+            } break;
+
+            case AF_INET6: {
+                const struct sockaddr_in6* sa =
+                    reinterpret_cast<const struct sockaddr_in6*>(&addr);
+                const uint8_t* a = sa->sin6_addr.s6_addr;
+                uint16_t       p = ntohs(sa->sin6_port);
+                snprintf(buf, bufLen,
+                        "%02X%02X:%02X%02X:%02X%02X:%02X%02X:"
+                        "%02X%02X:%02X%02X:%02X%02X:%02X%02X port %hd",
+                        a[0], a[1], a[ 2], a[ 3], a[ 4], a[ 5], a[ 6], a[ 7],
+                        a[8], a[9], a[10], a[11], a[12], a[13], a[14], a[15],
+                        p);
+            } break;
+
+            default:
+                snprintf(buf, bufLen,
+                         "<unknown sockaddr family %d>", addr.ss_family);
+                break;
+        }
+    } else {
+        snprintf(buf, bufLen, "<none>");
+    }
+
+    buf[bufLen - 1] = 0;
+}
+
+bool CommonTimeServer::sockaddrMatch(const sockaddr_storage& a1,
+                                     const sockaddr_storage& a2,
+                                     bool matchAddressOnly) {
+    if (a1.ss_family != a2.ss_family)
+        return false;
+
+    switch (a1.ss_family) {
+        case AF_INET: {
+            const struct sockaddr_in* sa1 =
+                reinterpret_cast<const struct sockaddr_in*>(&a1);
+            const struct sockaddr_in* sa2 =
+                reinterpret_cast<const struct sockaddr_in*>(&a2);
+
+            if (sa1->sin_addr.s_addr != sa2->sin_addr.s_addr)
+                return false;
+
+            return (matchAddressOnly || (sa1->sin_port == sa2->sin_port));
+        } break;
+
+        case AF_INET6: {
+            const struct sockaddr_in6* sa1 =
+                reinterpret_cast<const struct sockaddr_in6*>(&a1);
+            const struct sockaddr_in6* sa2 =
+                reinterpret_cast<const struct sockaddr_in6*>(&a2);
+
+            if (memcmp(&sa1->sin6_addr, &sa2->sin6_addr, sizeof(sa2->sin6_addr)))
+                return false;
+
+            return (matchAddressOnly || (sa1->sin6_port == sa2->sin6_port));
+        } break;
+
+        // Huh?  We don't deal in non-IPv[46] addresses.  Not sure how we got
+        // here, but we don't know how to comapre these addresses and simply
+        // default to a no-match decision.
+        default: return false;
+    }
+}
+
+bool CommonTimeServer::shouldPanicNotGettingGoodData() {
+    if (mClient_FirstSyncTX) {
+        int64_t now = mLocalClock.getLocalTime();
+        int64_t delta = now - (mClient_LastGoodSyncRX
+                             ? mClient_LastGoodSyncRX
+                             : mClient_FirstSyncTX);
+        int64_t deltaUsec = mCommonClock.localDurationToCommonDuration(delta);
+
+        if (deltaUsec >= kNoGoodDataPanicThresholdUsec)
+            return true;
+    }
+
+    return false;
+}
+
+void CommonTimeServer::PacketRTTLog::logTX(int64_t txTime) {
+    txTimes[wrPtr] = txTime;
+    rxTimes[wrPtr] = 0;
+    wrPtr = (wrPtr + 1) % RTT_LOG_SIZE;
+    if (!wrPtr)
+        logFull = true;
+}
+
+void CommonTimeServer::PacketRTTLog::logRX(int64_t txTime, int64_t rxTime) {
+    if (!logFull && !wrPtr)
+        return;
+
+    uint32_t i = logFull ? wrPtr : 0;
+    do {
+        if (txTimes[i] == txTime) {
+            rxTimes[i] = rxTime;
+            break;
+        }
+        i = (i + 1) % RTT_LOG_SIZE;
+    } while (i != wrPtr);
+}
+
+}  // namespace android
diff --git a/libs/common_time/common_time_server.h b/libs/common_time/common_time_server.h
new file mode 100644
index 0000000..6e18050
--- /dev/null
+++ b/libs/common_time/common_time_server.h
@@ -0,0 +1,324 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_COMMON_TIME_SERVER_H
+#define ANDROID_COMMON_TIME_SERVER_H
+
+#include <arpa/inet.h>
+#include <stdint.h>
+#include <sys/socket.h>
+
+#include <common_time/ICommonClock.h>
+#include <common_time/local_clock.h>
+#include <utils/String8.h>
+
+#include "clock_recovery.h"
+#include "common_clock.h"
+#include "common_time_server_packets.h"
+#include "utils.h"
+
+#define RTT_LOG_SIZE 30
+
+namespace android {
+
+class CommonClockService;
+class CommonTimeConfigService;
+
+/***** time service implementation *****/
+
+class CommonTimeServer : public Thread {
+  public:
+    CommonTimeServer();
+    ~CommonTimeServer();
+
+    bool startServices();
+
+    // Common Clock API methods
+    CommonClock&        getCommonClock()        { return mCommonClock; }
+    LocalClock&         getLocalClock()         { return mLocalClock; }
+    uint64_t            getTimelineID();
+    int32_t             getEstimatedError();
+    ICommonClock::State getState();
+    status_t            getMasterAddr(struct sockaddr_storage* addr);
+    status_t            isCommonTimeValid(bool* valid, uint32_t* timelineID);
+
+    // Config API methods
+    status_t getMasterElectionPriority(uint8_t *priority);
+    status_t setMasterElectionPriority(uint8_t priority);
+    status_t getMasterElectionEndpoint(struct sockaddr_storage *addr);
+    status_t setMasterElectionEndpoint(const struct sockaddr_storage *addr);
+    status_t getMasterElectionGroupId(uint64_t *id);
+    status_t setMasterElectionGroupId(uint64_t id);
+    status_t getInterfaceBinding(String8& ifaceName);
+    status_t setInterfaceBinding(const String8& ifaceName);
+    status_t getMasterAnnounceInterval(int *interval);
+    status_t setMasterAnnounceInterval(int interval);
+    status_t getClientSyncInterval(int *interval);
+    status_t setClientSyncInterval(int interval);
+    status_t getPanicThreshold(int *threshold);
+    status_t setPanicThreshold(int threshold);
+    status_t getAutoDisable(bool *autoDisable);
+    status_t setAutoDisable(bool autoDisable);
+    status_t forceNetworklessMasterMode();
+
+    // Method used by the CommonClockService to notify the core service about
+    // changes in the number of active common clock clients.
+    void reevaluateAutoDisableState(bool commonClockHasClients);
+
+    status_t dumpClockInterface(int fd, const Vector<String16>& args,
+                                size_t activeClients);
+    status_t dumpConfigInterface(int fd, const Vector<String16>& args);
+
+  private:
+    class PacketRTTLog {
+      public:
+        PacketRTTLog() {
+            resetLog();
+        }
+
+        void resetLog() {
+            wrPtr = 0;
+            logFull = 0;
+        }
+
+        void logTX(int64_t txTime);
+        void logRX(int64_t txTime, int64_t rxTime);
+        void dumpLog(int fd, const CommonClock& cclk);
+
+      private:
+        uint32_t wrPtr;
+        bool logFull;
+        int64_t txTimes[RTT_LOG_SIZE];
+        int64_t rxTimes[RTT_LOG_SIZE];
+    };
+
+    bool threadLoop();
+
+    bool runStateMachine_l();
+    bool setupSocket_l();
+
+    void assignTimelineID();
+    bool assignDeviceID();
+
+    static bool arbitrateMaster(uint64_t deviceID1, uint8_t devicePrio1,
+                                uint64_t deviceID2, uint8_t devicePrio2);
+
+    bool handlePacket();
+    bool handleWhoIsMasterRequest (const WhoIsMasterRequestPacket* request,
+                                   const sockaddr_storage& srcAddr);
+    bool handleWhoIsMasterResponse(const WhoIsMasterResponsePacket* response,
+                                   const sockaddr_storage& srcAddr);
+    bool handleSyncRequest        (const SyncRequestPacket* request,
+                                   const sockaddr_storage& srcAddr);
+    bool handleSyncResponse       (const SyncResponsePacket* response,
+                                   const sockaddr_storage& srcAddr);
+    bool handleMasterAnnouncement (const MasterAnnouncementPacket* packet,
+                                   const sockaddr_storage& srcAddr);
+
+    bool handleTimeout();
+    bool handleTimeoutInitial();
+    bool handleTimeoutClient();
+    bool handleTimeoutMaster();
+    bool handleTimeoutRonin();
+    bool handleTimeoutWaitForElection();
+
+    bool sendWhoIsMasterRequest();
+    bool sendSyncRequest();
+    bool sendMasterAnnouncement();
+
+    bool becomeClient(const sockaddr_storage& masterAddr,
+                      uint64_t masterDeviceID,
+                      uint8_t  masterDevicePriority,
+                      uint64_t timelineID,
+                      const char* cause);
+    bool becomeMaster(const char* cause);
+    bool becomeRonin(const char* cause);
+    bool becomeWaitForElection(const char* cause);
+    bool becomeInitial(const char* cause);
+
+    void notifyClockSync();
+    void notifyClockSyncLoss();
+
+    ICommonClock::State mState;
+    void setState(ICommonClock::State s);
+
+    void clearPendingWakeupEvents_l();
+    void wakeupThread_l();
+    void cleanupSocket_l();
+    void shutdownThread();
+
+    inline uint8_t effectivePriority() const {
+        return (mMasterPriority & 0x7F) |
+               (mForceLowPriority ? 0x00 : 0x80);
+    }
+
+    inline bool shouldAutoDisable() const {
+        return (mAutoDisable && !mCommonClockHasClients);
+    }
+
+    inline void resetSyncStats() {
+        mClient_SyncRequestPending = false;
+        mClient_SyncRequestTimeouts = 0;
+        mClient_SyncsSentToCurMaster = 0;
+        mClient_SyncRespsRXedFromCurMaster = 0;
+        mClient_ExpiredSyncRespsRXedFromCurMaster = 0;
+        mClient_FirstSyncTX = 0;
+        mClient_LastGoodSyncRX = 0;
+        mClient_PacketRTTLog.resetLog();
+    }
+
+    bool shouldPanicNotGettingGoodData();
+
+    // Helper to keep track of the state machine's current timeout
+    Timeout mCurTimeout;
+
+    // common clock, local clock abstraction, and clock recovery loop
+    CommonClock mCommonClock;
+    LocalClock mLocalClock;
+    ClockRecoveryLoop mClockRecovery;
+
+    // implementation of ICommonClock
+    sp<CommonClockService> mICommonClock;
+
+    // implementation of ICommonTimeConfig
+    sp<CommonTimeConfigService> mICommonTimeConfig;
+
+    // UDP socket for the time sync protocol
+    int mSocket;
+
+    // eventfd used to wakeup the work thread in response to configuration
+    // changes.
+    int mWakeupThreadFD;
+
+    // timestamp captured when a packet is received
+    int64_t mLastPacketRxLocalTime;
+
+    // ID of the timeline that this device is following
+    uint64_t mTimelineID;
+
+    // flag for whether the clock has been synced to a timeline
+    bool mClockSynced;
+
+    // flag used to indicate that clients should be considered to be lower
+    // priority than all of their peers during elections.  This flag is set and
+    // cleared by the state machine.  It is set when the client joins a new
+    // network.  If the client had been a master in the old network (or an
+    // isolated master with no network connectivity) it should defer to any
+    // masters which may already be on the network.  It will be cleared whenever
+    // the state machine transitions to the master state.
+    bool mForceLowPriority;
+    inline void setForceLowPriority(bool val) {
+        mForceLowPriority = val;
+        if (mState == ICommonClock::STATE_MASTER)
+            mClient_MasterDevicePriority = effectivePriority();
+    }
+
+    // Lock to synchronize access to internal state and configuration.
+    Mutex mLock;
+
+    // Flag updated by the common clock service to indicate that it does or does
+    // not currently have registered clients.  When the the auto disable flag is
+    // cleared on the common time service, the service will participate in
+    // network synchronization whenever it has a valid network interface to bind
+    // to.  When the auto disable flag is set on the common time service, it
+    // will only participate in network synchronization when it has both a valid
+    // interface AND currently active common clock clients.
+    bool mCommonClockHasClients;
+
+    // Internal logs used for dumpsys.
+    LogRing                 mStateChangeLog;
+    LogRing                 mElectionLog;
+    LogRing                 mBadPktLog;
+
+    // Configuration info
+    struct sockaddr_storage mMasterElectionEP;          // Endpoint over which we conduct master election
+    String8                 mBindIface;                 // Endpoint for the service to bind to.
+    bool                    mBindIfaceValid;            // whether or not the bind Iface is valid.
+    bool                    mBindIfaceDirty;            // whether or not the bind Iface is valid.
+    struct sockaddr_storage mMasterEP;                  // Endpoint of our current master (if any)
+    bool                    mMasterEPValid;
+    uint64_t                mDeviceID;                  // unique ID of this device
+    uint64_t                mSyncGroupID;               // synchronization group ID of this device.
+    uint8_t                 mMasterPriority;            // Priority of this device in master election.
+    uint32_t                mMasterAnnounceIntervalMs;
+    uint32_t                mSyncRequestIntervalMs;
+    uint32_t                mPanicThresholdUsec;
+    bool                    mAutoDisable;
+
+    // Config defaults.
+    static const char*      kDefaultMasterElectionAddr;
+    static const uint16_t   kDefaultMasterElectionPort;
+    static const uint64_t   kDefaultSyncGroupID;
+    static const uint8_t    kDefaultMasterPriority;
+    static const uint32_t   kDefaultMasterAnnounceIntervalMs;
+    static const uint32_t   kDefaultSyncRequestIntervalMs;
+    static const uint32_t   kDefaultPanicThresholdUsec;
+    static const bool       kDefaultAutoDisable;
+
+    // Priority mask and shift fields.
+    static const uint64_t kDeviceIDMask;
+    static const uint8_t  kDevicePriorityMask;
+    static const uint8_t  kDevicePriorityHiLowBit;
+    static const uint32_t kDevicePriorityShift;
+
+    // Unconfgurable constants
+    static const int      kSetupRetryTimeoutMs;
+    static const int64_t  kNoGoodDataPanicThresholdUsec;
+    static const uint32_t kRTTDiscardPanicThreshMultiplier;
+
+    /*** status while in the Initial state ***/
+    int mInitial_WhoIsMasterRequestTimeouts;
+    static const int kInitial_NumWhoIsMasterRetries;
+    static const int kInitial_WhoIsMasterTimeoutMs;
+
+    /*** status while in the Client state ***/
+    uint64_t mClient_MasterDeviceID;
+    uint8_t mClient_MasterDevicePriority;
+    bool mClient_SyncRequestPending;
+    int mClient_SyncRequestTimeouts;
+    uint32_t mClient_SyncsSentToCurMaster;
+    uint32_t mClient_SyncRespsRXedFromCurMaster;
+    uint32_t mClient_ExpiredSyncRespsRXedFromCurMaster;
+    int64_t mClient_FirstSyncTX;
+    int64_t mClient_LastGoodSyncRX;
+    PacketRTTLog mClient_PacketRTTLog;
+    static const int kClient_NumSyncRequestRetries;
+
+
+    /*** status while in the Master state ***/
+    static const uint32_t kDefaultMaster_AnnouncementIntervalMs;
+
+    /*** status while in the Ronin state ***/
+    int mRonin_WhoIsMasterRequestTimeouts;
+    static const int kRonin_NumWhoIsMasterRetries;
+    static const int kRonin_WhoIsMasterTimeoutMs;
+
+    /*** status while in the WaitForElection state ***/
+    static const int kWaitForElection_TimeoutMs;
+
+    static const int kInfiniteTimeout;
+
+    static const char* stateToString(ICommonClock::State s);
+    static void sockaddrToString(const sockaddr_storage& addr, bool addrValid,
+                                 char* buf, size_t bufLen);
+    static bool sockaddrMatch(const sockaddr_storage& a1,
+                              const sockaddr_storage& a2,
+                              bool matchAddressOnly);
+};
+
+}  // namespace android
+
+#endif  // ANDROID_COMMON_TIME_SERVER_H
diff --git a/libs/common_time/common_time_server_api.cpp b/libs/common_time/common_time_server_api.cpp
new file mode 100644
index 0000000..e157071
--- /dev/null
+++ b/libs/common_time/common_time_server_api.cpp
@@ -0,0 +1,438 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * A service that exchanges time synchronization information between
+ * a master that defines a timeline and clients that follow the timeline.
+ */
+
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+
+#include <binder/IServiceManager.h>
+#include <binder/IPCThreadState.h>
+
+#include "common_time_server.h"
+
+namespace android {
+
+//
+// Clock API
+//
+uint64_t CommonTimeServer::getTimelineID() {
+    AutoMutex _lock(&mLock);
+    return mTimelineID;
+}
+
+ICommonClock::State CommonTimeServer::getState() {
+    AutoMutex _lock(&mLock);
+    return mState;
+}
+
+status_t CommonTimeServer::getMasterAddr(struct sockaddr_storage* addr) {
+    AutoMutex _lock(&mLock);
+    if (mMasterEPValid) {
+        memcpy(addr, &mMasterEP, sizeof(*addr));
+        return OK;
+    }
+
+    return UNKNOWN_ERROR;
+}
+
+int32_t CommonTimeServer::getEstimatedError() {
+    AutoMutex _lock(&mLock);
+
+    if (ICommonClock::STATE_MASTER == mState)
+        return 0;
+
+    if (!mClockSynced)
+        return ICommonClock::kErrorEstimateUnknown;
+
+    return mClockRecovery.getLastErrorEstimate();
+}
+
+status_t CommonTimeServer::isCommonTimeValid(bool* valid,
+                                             uint32_t* timelineID) {
+    AutoMutex _lock(&mLock);
+    *valid = mCommonClock.isValid();
+    *timelineID = mTimelineID;
+    return OK;
+}
+
+//
+// Config API
+//
+status_t CommonTimeServer::getMasterElectionPriority(uint8_t *priority) {
+    AutoMutex _lock(&mLock);
+    *priority = mMasterPriority;
+    return OK;
+}
+
+status_t CommonTimeServer::setMasterElectionPriority(uint8_t priority) {
+    AutoMutex _lock(&mLock);
+
+    if (priority > 0x7F)
+        return BAD_VALUE;
+
+    mMasterPriority = priority;
+    return OK;
+}
+
+status_t CommonTimeServer::getMasterElectionEndpoint(
+        struct sockaddr_storage *addr) {
+    AutoMutex _lock(&mLock);
+    memcpy(addr, &mMasterElectionEP, sizeof(*addr));
+    return OK;
+}
+
+status_t CommonTimeServer::setMasterElectionEndpoint(
+        const struct sockaddr_storage *addr) {
+    AutoMutex _lock(&mLock);
+
+    if (!addr)
+        return BAD_VALUE;
+
+    // TODO: add proper support for IPv6
+    if (addr->ss_family != AF_INET)
+        return BAD_VALUE;
+
+    // Only multicast and broadcast endpoints with explicit ports are allowed.
+    uint16_t ipv4Port = ntohs(
+        reinterpret_cast<const struct sockaddr_in*>(addr)->sin_port);
+    if (!ipv4Port)
+        return BAD_VALUE;
+
+    uint32_t ipv4Addr = ntohl(
+        reinterpret_cast<const struct sockaddr_in*>(addr)->sin_addr.s_addr);
+    if ((ipv4Addr != 0xFFFFFFFF) && (0xE0000000 != (ipv4Addr & 0xF0000000)))
+        return BAD_VALUE;
+
+    memcpy(&mMasterElectionEP, addr, sizeof(mMasterElectionEP));
+
+    // Force a rebind in order to change election enpoints.
+    mBindIfaceDirty = true;
+    wakeupThread_l();
+    return OK;
+}
+
+status_t CommonTimeServer::getMasterElectionGroupId(uint64_t *id) {
+    AutoMutex _lock(&mLock);
+    *id = mSyncGroupID;
+    return OK;
+}
+
+status_t CommonTimeServer::setMasterElectionGroupId(uint64_t id) {
+    AutoMutex _lock(&mLock);
+    mSyncGroupID = id;
+    return OK;
+}
+
+status_t CommonTimeServer::getInterfaceBinding(String8& ifaceName) {
+    AutoMutex _lock(&mLock);
+    if (!mBindIfaceValid)
+        return INVALID_OPERATION;
+    ifaceName = mBindIface;
+    return OK;
+}
+
+status_t CommonTimeServer::setInterfaceBinding(const String8& ifaceName) {
+    AutoMutex _lock(&mLock);
+
+    mBindIfaceDirty = true;
+    if (ifaceName.size()) {
+        mBindIfaceValid = true;
+        mBindIface = ifaceName;
+    } else {
+        mBindIfaceValid = false;
+        mBindIface.clear();
+    }
+
+    wakeupThread_l();
+    return OK;
+}
+
+status_t CommonTimeServer::getMasterAnnounceInterval(int *interval) {
+    AutoMutex _lock(&mLock);
+    *interval = mMasterAnnounceIntervalMs;
+    return OK;
+}
+
+status_t CommonTimeServer::setMasterAnnounceInterval(int interval) {
+    AutoMutex _lock(&mLock);
+
+    if (interval > (6 *3600000)) // Max interval is once every 6 hrs
+        return BAD_VALUE;
+
+    if (interval < 500) // Min interval is once per 0.5 seconds
+        return BAD_VALUE;
+
+    mMasterAnnounceIntervalMs = interval;
+    if (ICommonClock::STATE_MASTER == mState) {
+        int pendingTimeout = mCurTimeout.msecTillTimeout();
+        if ((kInfiniteTimeout == pendingTimeout) ||
+            (pendingTimeout > interval)) {
+            mCurTimeout.setTimeout(mMasterAnnounceIntervalMs);
+            wakeupThread_l();
+        }
+    }
+
+    return OK;
+}
+
+status_t CommonTimeServer::getClientSyncInterval(int *interval) {
+    AutoMutex _lock(&mLock);
+    *interval = mSyncRequestIntervalMs;
+    return OK;
+}
+
+status_t CommonTimeServer::setClientSyncInterval(int interval) {
+    AutoMutex _lock(&mLock);
+
+    if (interval > (3600000)) // Max interval is once every 60 min
+        return BAD_VALUE;
+
+    if (interval < 250) // Min interval is once per 0.25 seconds
+        return BAD_VALUE;
+
+    mSyncRequestIntervalMs = interval;
+    if (ICommonClock::STATE_CLIENT == mState) {
+        int pendingTimeout = mCurTimeout.msecTillTimeout();
+        if ((kInfiniteTimeout == pendingTimeout) ||
+            (pendingTimeout > interval)) {
+            mCurTimeout.setTimeout(mSyncRequestIntervalMs);
+            wakeupThread_l();
+        }
+    }
+
+    return OK;
+}
+
+status_t CommonTimeServer::getPanicThreshold(int *threshold) {
+    AutoMutex _lock(&mLock);
+    *threshold = mPanicThresholdUsec;
+    return OK;
+}
+
+status_t CommonTimeServer::setPanicThreshold(int threshold) {
+    AutoMutex _lock(&mLock);
+
+    if (threshold < 1000) // Min threshold is 1mSec
+        return BAD_VALUE;
+
+    mPanicThresholdUsec = threshold;
+    return OK;
+}
+
+status_t CommonTimeServer::getAutoDisable(bool *autoDisable) {
+    AutoMutex _lock(&mLock);
+    *autoDisable = mAutoDisable;
+    return OK;
+}
+
+status_t CommonTimeServer::setAutoDisable(bool autoDisable) {
+    AutoMutex _lock(&mLock);
+    mAutoDisable = autoDisable;
+    wakeupThread_l();
+    return OK;
+}
+
+status_t CommonTimeServer::forceNetworklessMasterMode() {
+    AutoMutex _lock(&mLock);
+
+    // Can't force networkless master mode if we are currently bound to a
+    // network.
+    if (mSocket >= 0)
+        return INVALID_OPERATION;
+
+    becomeMaster("force networkless");
+
+    return OK;
+}
+
+void CommonTimeServer::reevaluateAutoDisableState(bool commonClockHasClients) {
+    AutoMutex _lock(&mLock);
+    bool needWakeup = (mAutoDisable && mMasterEPValid &&
+                      (commonClockHasClients != mCommonClockHasClients));
+
+    mCommonClockHasClients = commonClockHasClients;
+
+    if (needWakeup) {
+        ALOGI("Waking up service, auto-disable is engaged and service now has%s"
+             " clients", mCommonClockHasClients ? "" : " no");
+        wakeupThread_l();
+    }
+}
+
+#define dump_printf(a, b...) do {                 \
+    int res;                                      \
+    res = snprintf(buffer, sizeof(buffer), a, b); \
+    buffer[sizeof(buffer) - 1] = 0;               \
+    if (res > 0)                                  \
+        write(fd, buffer, res);                   \
+} while (0)
+#define checked_percentage(a, b) ((0 == b) ? 0.0f : ((100.0f * a) / b))
+
+status_t CommonTimeServer::dumpClockInterface(int fd,
+                                              const Vector<String16>& args,
+                                              size_t activeClients) {
+    AutoMutex _lock(&mLock);
+    const size_t SIZE = 256;
+    char buffer[SIZE];
+
+    if (checkCallingPermission(String16("android.permission.DUMP")) == false) {
+        snprintf(buffer, SIZE, "Permission Denial: "
+                 "can't dump CommonClockService from pid=%d, uid=%d\n",
+                 IPCThreadState::self()->getCallingPid(),
+                 IPCThreadState::self()->getCallingUid());
+        write(fd, buffer, strlen(buffer));
+    } else {
+        int64_t commonTime;
+        int64_t localTime;
+        bool    synced;
+        char maStr[64];
+
+        localTime  = mLocalClock.getLocalTime();
+        synced     = (OK == mCommonClock.localToCommon(localTime, &commonTime));
+        sockaddrToString(mMasterEP, mMasterEPValid, maStr, sizeof(maStr));
+
+        dump_printf("Common Clock Service Status\nLocal time     : %lld\n",
+                    localTime);
+
+        if (synced)
+            dump_printf("Common time    : %lld\n", commonTime);
+        else
+            dump_printf("Common time    : %s\n", "not synced");
+
+        dump_printf("Timeline ID    : %016llx\n", mTimelineID);
+        dump_printf("State          : %s\n", stateToString(mState));
+        dump_printf("Master Addr    : %s\n", maStr);
+
+
+        if (synced) {
+            int32_t est = (ICommonClock::STATE_MASTER != mState)
+                        ? mClockRecovery.getLastErrorEstimate()
+                        : 0;
+            dump_printf("Error Est.     : %.3f msec\n",
+                        static_cast<float>(est) / 1000.0);
+        } else {
+            dump_printf("Error Est.     : %s\n", "unknown");
+        }
+
+        dump_printf("Syncs TXes     : %u\n", mClient_SyncsSentToCurMaster);
+        dump_printf("Syncs RXes     : %u (%.2f%%)\n",
+                    mClient_SyncRespsRXedFromCurMaster,
+                    checked_percentage(
+                        mClient_SyncRespsRXedFromCurMaster,
+                        mClient_SyncsSentToCurMaster));
+        dump_printf("RXs Expired    : %u (%.2f%%)\n",
+                    mClient_ExpiredSyncRespsRXedFromCurMaster,
+                    checked_percentage(
+                        mClient_ExpiredSyncRespsRXedFromCurMaster,
+                        mClient_SyncsSentToCurMaster));
+
+        if (!mClient_LastGoodSyncRX) {
+            dump_printf("Last Good RX   : %s\n", "unknown");
+        } else {
+            int64_t localDelta, usecDelta;
+            localDelta = localTime - mClient_LastGoodSyncRX;
+            usecDelta  = mCommonClock.localDurationToCommonDuration(localDelta);
+            dump_printf("Last Good RX   : %lld uSec ago\n", usecDelta);
+        }
+
+        dump_printf("Active Clients : %u\n", activeClients);
+        mClient_PacketRTTLog.dumpLog(fd, mCommonClock);
+        mStateChangeLog.dumpLog(fd);
+        mElectionLog.dumpLog(fd);
+        mBadPktLog.dumpLog(fd);
+    }
+
+    return NO_ERROR;
+}
+
+status_t CommonTimeServer::dumpConfigInterface(int fd,
+                                               const Vector<String16>& args) {
+    AutoMutex _lock(&mLock);
+    const size_t SIZE = 256;
+    char buffer[SIZE];
+
+    if (checkCallingPermission(String16("android.permission.DUMP")) == false) {
+        snprintf(buffer, SIZE, "Permission Denial: "
+                 "can't dump CommonTimeConfigService from pid=%d, uid=%d\n",
+                 IPCThreadState::self()->getCallingPid(),
+                 IPCThreadState::self()->getCallingUid());
+        write(fd, buffer, strlen(buffer));
+    } else {
+        char meStr[64];
+
+        sockaddrToString(mMasterElectionEP, true, meStr, sizeof(meStr));
+
+        dump_printf("Common Time Config Service Status\n"
+                    "Bound Interface           : %s\n",
+                    mBindIfaceValid ? mBindIface.string() : "<unbound>");
+        dump_printf("Master Election Endpoint  : %s\n", meStr);
+        dump_printf("Master Election Group ID  : %016llx\n", mSyncGroupID);
+        dump_printf("Master Announce Interval  : %d mSec\n",
+                    mMasterAnnounceIntervalMs);
+        dump_printf("Client Sync Interval      : %d mSec\n",
+                    mSyncRequestIntervalMs);
+        dump_printf("Panic Threshold           : %d uSec\n",
+                    mPanicThresholdUsec);
+        dump_printf("Base ME Prio              : 0x%02x\n",
+                    static_cast<uint32_t>(mMasterPriority));
+        dump_printf("Effective ME Prio         : 0x%02x\n",
+                    static_cast<uint32_t>(effectivePriority()));
+        dump_printf("Auto Disable Allowed      : %s\n",
+                    mAutoDisable ? "yes" : "no");
+        dump_printf("Auto Disable Engaged      : %s\n",
+                    shouldAutoDisable() ? "yes" : "no");
+    }
+
+    return NO_ERROR;
+}
+
+void CommonTimeServer::PacketRTTLog::dumpLog(int fd, const CommonClock& cclk) {
+    const size_t SIZE = 256;
+    char buffer[SIZE];
+    uint32_t avail = !logFull ? wrPtr : RTT_LOG_SIZE;
+
+    if (!avail)
+        return;
+
+    dump_printf("\nPacket Log (%d entries)\n", avail);
+
+    uint32_t ndx = 0;
+    uint32_t i = logFull ? wrPtr : 0;
+    do {
+        if (rxTimes[i]) {
+            int64_t delta = rxTimes[i] - txTimes[i];
+            int64_t deltaUsec = cclk.localDurationToCommonDuration(delta);
+            dump_printf("pkt[%2d] : localTX %12lld localRX %12lld "
+                        "(%.3f msec RTT)\n",
+                        ndx, txTimes[i], rxTimes[i],
+                        static_cast<float>(deltaUsec) / 1000.0);
+        } else {
+            dump_printf("pkt[%2d] : localTX %12lld localRX never\n",
+                        ndx, txTimes[i]);
+        }
+        i = (i + 1) % RTT_LOG_SIZE;
+        ndx++;
+    } while (i != wrPtr);
+}
+
+#undef dump_printf
+#undef checked_percentage
+
+}  // namespace android
diff --git a/libs/common_time/common_time_server_packets.cpp b/libs/common_time/common_time_server_packets.cpp
new file mode 100644
index 0000000..9833c37
--- /dev/null
+++ b/libs/common_time/common_time_server_packets.cpp
@@ -0,0 +1,293 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * A service that exchanges time synchronization information between
+ * a master that defines a timeline and clients that follow the timeline.
+ */
+
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+
+#include <arpa/inet.h>
+#include <stdint.h>
+
+#include "common_time_server_packets.h"
+
+namespace android {
+
+const uint32_t TimeServicePacketHeader::kMagic =
+    (static_cast<uint32_t>('c') << 24) |
+    (static_cast<uint32_t>('c') << 16) |
+    (static_cast<uint32_t>('l') <<  8) |
+     static_cast<uint32_t>('k');
+
+const uint16_t TimeServicePacketHeader::kCurVersion = 1;
+
+#define SERIALIZE_FIELD(field_name, type, converter)        \
+    do {                                                    \
+        if ((offset + sizeof(field_name)) > length)         \
+            return -1;                                      \
+        *((type*)(data + offset)) = converter(field_name);  \
+        offset += sizeof(field_name);                       \
+    } while (0)
+#define SERIALIZE_INT16(field_name) SERIALIZE_FIELD(field_name, int16_t, htons)
+#define SERIALIZE_INT32(field_name) SERIALIZE_FIELD(field_name, int32_t, htonl)
+#define SERIALIZE_INT64(field_name) SERIALIZE_FIELD(field_name, int64_t, htonq)
+
+#define DESERIALIZE_FIELD(field_name, type, converter)      \
+    do {                                                    \
+        if ((offset + sizeof(field_name)) > length)         \
+            return -1;                                      \
+        field_name = converter(*((type*)(data + offset)));  \
+        offset += sizeof(field_name);                       \
+    } while (0)
+#define DESERIALIZE_INT16(field_name) DESERIALIZE_FIELD(field_name, int16_t, ntohs)
+#define DESERIALIZE_INT32(field_name) DESERIALIZE_FIELD(field_name, int32_t, ntohl)
+#define DESERIALIZE_INT64(field_name) DESERIALIZE_FIELD(field_name, int64_t, ntohq)
+
+#define kDevicePriorityShift 56
+#define kDeviceIDMask ((static_cast<uint64_t>(1) << kDevicePriorityShift) - 1)
+
+inline uint64_t packDeviceID(uint64_t devID, uint8_t prio) {
+    return (devID & kDeviceIDMask) |
+           (static_cast<uint64_t>(prio) << kDevicePriorityShift);
+}
+
+inline uint64_t unpackDeviceID(uint64_t packed) {
+    return (packed & kDeviceIDMask);
+}
+
+inline uint8_t unpackDevicePriority(uint64_t packed) {
+    return static_cast<uint8_t>(packed >> kDevicePriorityShift);
+}
+
+ssize_t TimeServicePacketHeader::serializeHeader(uint8_t* data,
+                                                 uint32_t length) {
+    ssize_t offset = 0;
+    int16_t pktType = static_cast<int16_t>(packetType);
+    SERIALIZE_INT32(magic);
+    SERIALIZE_INT16(version);
+    SERIALIZE_INT16(pktType);
+    SERIALIZE_INT64(timelineID);
+    SERIALIZE_INT64(syncGroupID);
+    return offset;
+}
+
+ssize_t TimeServicePacketHeader::deserializeHeader(const uint8_t* data,
+                                                   uint32_t length) {
+    ssize_t offset = 0;
+    int16_t tmp;
+    DESERIALIZE_INT32(magic);
+    DESERIALIZE_INT16(version);
+    DESERIALIZE_INT16(tmp);
+    DESERIALIZE_INT64(timelineID);
+    DESERIALIZE_INT64(syncGroupID);
+    packetType = static_cast<TimeServicePacketType>(tmp);
+    return offset;
+}
+
+ssize_t TimeServicePacketHeader::serializePacket(uint8_t* data,
+                                                 uint32_t length) {
+    ssize_t ret, tmp;
+
+    ret = serializeHeader(data, length);
+    if (ret < 0)
+        return ret;
+
+    data += ret;
+    length -= ret;
+
+    switch (packetType) {
+        case TIME_PACKET_WHO_IS_MASTER_REQUEST:
+            tmp =((WhoIsMasterRequestPacket*)(this))->serializePacket(data,
+                                                                      length);
+            break;
+        case TIME_PACKET_WHO_IS_MASTER_RESPONSE:
+            tmp =((WhoIsMasterResponsePacket*)(this))->serializePacket(data,
+                                                                       length);
+            break;
+        case TIME_PACKET_SYNC_REQUEST:
+            tmp =((SyncRequestPacket*)(this))->serializePacket(data, length);
+            break;
+        case TIME_PACKET_SYNC_RESPONSE:
+            tmp =((SyncResponsePacket*)(this))->serializePacket(data, length);
+            break;
+        case TIME_PACKET_MASTER_ANNOUNCEMENT:
+            tmp =((MasterAnnouncementPacket*)(this))->serializePacket(data,
+                                                                      length);
+            break;
+        default:
+            return -1;
+    }
+
+    if (tmp < 0)
+        return tmp;
+
+    return ret + tmp;
+}
+
+ssize_t UniversalTimeServicePacket::deserializePacket(
+        const uint8_t* data,
+        uint32_t length,
+        uint64_t expectedSyncGroupID) {
+    ssize_t ret;
+    TimeServicePacketHeader* header;
+    if (length < 8)
+        return -1;
+
+    packetType = ntohs(*((uint16_t*)(data + 6)));
+    switch (packetType) {
+        case TIME_PACKET_WHO_IS_MASTER_REQUEST:
+            ret = p.who_is_master_request.deserializePacket(data, length);
+            header = &p.who_is_master_request;
+            break;
+        case TIME_PACKET_WHO_IS_MASTER_RESPONSE:
+            ret = p.who_is_master_response.deserializePacket(data, length);
+            header = &p.who_is_master_response;
+            break;
+        case TIME_PACKET_SYNC_REQUEST:
+            ret = p.sync_request.deserializePacket(data, length);
+            header = &p.sync_request;
+            break;
+        case TIME_PACKET_SYNC_RESPONSE:
+            ret = p.sync_response.deserializePacket(data, length);
+            header = &p.sync_response;
+            break;
+        case TIME_PACKET_MASTER_ANNOUNCEMENT:
+            ret = p.master_announcement.deserializePacket(data, length);
+            header = &p.master_announcement;
+            break;
+        default:
+            return -1;
+    }
+
+    if ((ret >= 0) && !header->checkPacket(expectedSyncGroupID))
+        ret = -1;
+
+    return ret;
+}
+
+ssize_t WhoIsMasterRequestPacket::serializePacket(uint8_t* data,
+                                                  uint32_t length) {
+    ssize_t offset = serializeHeader(data, length);
+    if (offset > 0) {
+        uint64_t packed = packDeviceID(senderDeviceID, senderDevicePriority);
+        SERIALIZE_INT64(packed);
+    }
+    return offset;
+}
+
+ssize_t WhoIsMasterRequestPacket::deserializePacket(const uint8_t* data,
+                                                    uint32_t length) {
+    ssize_t offset = deserializeHeader(data, length);
+    if (offset > 0) {
+        uint64_t packed;
+        DESERIALIZE_INT64(packed);
+        senderDeviceID       = unpackDeviceID(packed);
+        senderDevicePriority = unpackDevicePriority(packed);
+    }
+    return offset;
+}
+
+ssize_t WhoIsMasterResponsePacket::serializePacket(uint8_t* data,
+                                                   uint32_t length) {
+    ssize_t offset = serializeHeader(data, length);
+    if (offset > 0) {
+        uint64_t packed = packDeviceID(deviceID, devicePriority);
+        SERIALIZE_INT64(packed);
+    }
+    return offset;
+}
+
+ssize_t WhoIsMasterResponsePacket::deserializePacket(const uint8_t* data,
+                                                     uint32_t length) {
+    ssize_t offset = deserializeHeader(data, length);
+    if (offset > 0) {
+        uint64_t packed;
+        DESERIALIZE_INT64(packed);
+        deviceID       = unpackDeviceID(packed);
+        devicePriority = unpackDevicePriority(packed);
+    }
+    return offset;
+}
+
+ssize_t SyncRequestPacket::serializePacket(uint8_t* data,
+                                           uint32_t length) {
+    ssize_t offset = serializeHeader(data, length);
+    if (offset > 0) {
+        SERIALIZE_INT64(clientTxLocalTime);
+    }
+    return offset;
+}
+
+ssize_t SyncRequestPacket::deserializePacket(const uint8_t* data,
+                                             uint32_t length) {
+    ssize_t offset = deserializeHeader(data, length);
+    if (offset > 0) {
+        DESERIALIZE_INT64(clientTxLocalTime);
+    }
+    return offset;
+}
+
+ssize_t SyncResponsePacket::serializePacket(uint8_t* data,
+                                            uint32_t length) {
+    ssize_t offset = serializeHeader(data, length);
+    if (offset > 0) {
+        SERIALIZE_INT64(clientTxLocalTime);
+        SERIALIZE_INT64(masterRxCommonTime);
+        SERIALIZE_INT64(masterTxCommonTime);
+        SERIALIZE_INT32(nak);
+    }
+    return offset;
+}
+
+ssize_t SyncResponsePacket::deserializePacket(const uint8_t* data,
+                                              uint32_t length) {
+    ssize_t offset = deserializeHeader(data, length);
+    if (offset > 0) {
+        DESERIALIZE_INT64(clientTxLocalTime);
+        DESERIALIZE_INT64(masterRxCommonTime);
+        DESERIALIZE_INT64(masterTxCommonTime);
+        DESERIALIZE_INT32(nak);
+    }
+    return offset;
+}
+
+ssize_t MasterAnnouncementPacket::serializePacket(uint8_t* data,
+                                                  uint32_t length) {
+    ssize_t offset = serializeHeader(data, length);
+    if (offset > 0) {
+        uint64_t packed = packDeviceID(deviceID, devicePriority);
+        SERIALIZE_INT64(packed);
+    }
+    return offset;
+}
+
+ssize_t MasterAnnouncementPacket::deserializePacket(const uint8_t* data,
+                                                    uint32_t length) {
+    ssize_t offset = deserializeHeader(data, length);
+    if (offset > 0) {
+        uint64_t packed;
+        DESERIALIZE_INT64(packed);
+        deviceID       = unpackDeviceID(packed);
+        devicePriority = unpackDevicePriority(packed);
+    }
+    return offset;
+}
+
+}  // namespace android
+
diff --git a/libs/common_time/common_time_server_packets.h b/libs/common_time/common_time_server_packets.h
new file mode 100644
index 0000000..57ba8a2
--- /dev/null
+++ b/libs/common_time/common_time_server_packets.h
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_COMMON_TIME_SERVER_PACKETS_H
+#define ANDROID_COMMON_TIME_SERVER_PACKETS_H
+
+#include <stdint.h>
+#include <common_time/ICommonClock.h>
+
+namespace android {
+
+/***** time sync protocol packets *****/
+
+enum TimeServicePacketType {
+    TIME_PACKET_WHO_IS_MASTER_REQUEST = 1,
+    TIME_PACKET_WHO_IS_MASTER_RESPONSE,
+    TIME_PACKET_SYNC_REQUEST,
+    TIME_PACKET_SYNC_RESPONSE,
+    TIME_PACKET_MASTER_ANNOUNCEMENT,
+};
+
+class TimeServicePacketHeader {
+  public:
+    friend class UniversalTimeServicePacket;
+    // magic number identifying the protocol
+    uint32_t magic;
+
+    // protocol version of the packet
+    uint16_t version;
+
+    // type of the packet
+    TimeServicePacketType packetType;
+
+    // the timeline ID
+    uint64_t timelineID;
+
+    // synchronization group this packet belongs to (used to operate multiple
+    // synchronization domains which all use the same master election endpoint)
+    uint64_t syncGroupID;
+
+    ssize_t serializePacket(uint8_t* data, uint32_t length);
+
+  protected:
+    void initHeader(TimeServicePacketType type,
+                    const uint64_t tlID,
+                    const uint64_t groupID) {
+        magic              = kMagic;
+        version            = kCurVersion;
+        packetType         = type;
+        timelineID         = tlID;
+        syncGroupID        = groupID;
+    }
+
+    bool checkPacket(uint64_t expectedSyncGroupID) const {
+        return ((magic       == kMagic) &&
+                (version     == kCurVersion) &&
+                (!expectedSyncGroupID || (syncGroupID == expectedSyncGroupID)));
+    }
+
+    ssize_t serializeHeader(uint8_t* data, uint32_t length);
+    ssize_t deserializeHeader(const uint8_t* data, uint32_t length);
+
+  private:
+    static const uint32_t kMagic;
+    static const uint16_t kCurVersion;
+};
+
+// packet querying for a suitable master
+class WhoIsMasterRequestPacket : public TimeServicePacketHeader {
+  public:
+    uint64_t senderDeviceID;
+    uint8_t senderDevicePriority;
+
+    void initHeader(const uint64_t groupID) {
+        TimeServicePacketHeader::initHeader(TIME_PACKET_WHO_IS_MASTER_REQUEST,
+                                            ICommonClock::kInvalidTimelineID,
+                                            groupID);
+    }
+
+    ssize_t serializePacket(uint8_t* data, uint32_t length);
+    ssize_t deserializePacket(const uint8_t* data, uint32_t length);
+};
+
+// response to a WhoIsMaster request
+class WhoIsMasterResponsePacket : public TimeServicePacketHeader {
+  public:
+    uint64_t deviceID;
+    uint8_t devicePriority;
+
+    void initHeader(const uint64_t tlID, const uint64_t groupID) {
+        TimeServicePacketHeader::initHeader(TIME_PACKET_WHO_IS_MASTER_RESPONSE,
+                                            tlID, groupID);
+    }
+
+    ssize_t serializePacket(uint8_t* data, uint32_t length);
+    ssize_t deserializePacket(const uint8_t* data, uint32_t length);
+};
+
+// packet sent by a client requesting correspondence between local
+// and common time
+class SyncRequestPacket : public TimeServicePacketHeader {
+  public:
+    // local time when this request was transmitted
+    int64_t clientTxLocalTime;
+
+    void initHeader(const uint64_t tlID, const uint64_t groupID) {
+        TimeServicePacketHeader::initHeader(TIME_PACKET_SYNC_REQUEST,
+                                            tlID, groupID);
+    }
+
+    ssize_t serializePacket(uint8_t* data, uint32_t length);
+    ssize_t deserializePacket(const uint8_t* data, uint32_t length);
+};
+
+// response to a sync request sent by the master
+class SyncResponsePacket : public TimeServicePacketHeader {
+  public:
+    // local time when this request was transmitted by the client
+    int64_t clientTxLocalTime;
+
+    // common time when the master received the request
+    int64_t masterRxCommonTime;
+
+    // common time when the master transmitted the response
+    int64_t masterTxCommonTime;
+
+    // flag that is set if the recipient of the sync request is not acting
+    // as a master for the requested timeline
+    uint32_t nak;
+
+    void initHeader(const uint64_t tlID, const uint64_t groupID) {
+        TimeServicePacketHeader::initHeader(TIME_PACKET_SYNC_RESPONSE,
+                                            tlID, groupID);
+    }
+
+    ssize_t serializePacket(uint8_t* data, uint32_t length);
+    ssize_t deserializePacket(const uint8_t* data, uint32_t length);
+};
+
+// announcement of the master's presence
+class MasterAnnouncementPacket : public TimeServicePacketHeader {
+  public:
+    // the master's device ID
+    uint64_t deviceID;
+    uint8_t devicePriority;
+
+    void initHeader(const uint64_t tlID, const uint64_t groupID) {
+        TimeServicePacketHeader::initHeader(TIME_PACKET_MASTER_ANNOUNCEMENT,
+                                            tlID, groupID);
+    }
+
+    ssize_t serializePacket(uint8_t* data, uint32_t length);
+    ssize_t deserializePacket(const uint8_t* data, uint32_t length);
+};
+
+class UniversalTimeServicePacket {
+  public:
+    uint16_t packetType;
+    union {
+        WhoIsMasterRequestPacket  who_is_master_request;
+        WhoIsMasterResponsePacket who_is_master_response;
+        SyncRequestPacket         sync_request;
+        SyncResponsePacket        sync_response;
+        MasterAnnouncementPacket  master_announcement;
+    } p;
+
+    ssize_t deserializePacket(const uint8_t* data,
+                              uint32_t       length,
+                              uint64_t       expectedSyncGroupID);
+};
+
+};  // namespace android
+
+#endif  // ANDROID_COMMON_TIME_SERVER_PACKETS_H
+
+
diff --git a/libs/common_time/diag_thread.cpp b/libs/common_time/diag_thread.cpp
new file mode 100644
index 0000000..4cb9551
--- /dev/null
+++ b/libs/common_time/diag_thread.cpp
@@ -0,0 +1,323 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+
+#include <fcntl.h>
+#include <linux/in.h>
+#include <linux/tcp.h>
+#include <poll.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <utils/Errors.h>
+#include <utils/misc.h>
+
+#include <common_time/local_clock.h>
+
+#include "common_clock.h"
+#include "diag_thread.h"
+
+#define kMaxEvents 16
+#define kListenPort 9876
+
+static bool setNonblocking(int fd) {
+    int flags = fcntl(fd, F_GETFL);
+    if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) < 0) {
+        ALOGE("Failed to set socket (%d) to non-blocking mode (errno %d)",
+             fd, errno);
+        return false;
+    }
+
+    return true;
+}
+
+static bool setNodelay(int fd) {
+    int tmp = 1;
+    if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &tmp, sizeof(tmp)) < 0) {
+        ALOGE("Failed to set socket (%d) to no-delay mode (errno %d)",
+             fd, errno);
+        return false;
+    }
+
+    return true;
+}
+
+namespace android {
+
+DiagThread::DiagThread(CommonClock* common_clock, LocalClock* local_clock) {
+    common_clock_ = common_clock;
+    local_clock_ = local_clock;
+    listen_fd_ = -1;
+    data_fd_ = -1;
+    kernel_logID_basis_known_ = false;
+    discipline_log_ID_ = 0;
+}
+
+DiagThread::~DiagThread() {
+}
+
+status_t DiagThread::startWorkThread() {
+    status_t res;
+    stopWorkThread();
+    res = run("Diag");
+
+    if (res != OK)
+        ALOGE("Failed to start work thread (res = %d)", res);
+
+    return res;
+}
+
+void DiagThread::stopWorkThread() {
+    status_t res;
+    res = requestExitAndWait(); // block until thread exit.
+    if (res != OK)
+        ALOGE("Failed to stop work thread (res = %d)", res);
+}
+
+bool DiagThread::openListenSocket() {
+    bool ret = false;
+    int flags;
+    cleanupListenSocket();
+
+    if ((listen_fd_ = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
+        ALOGE("Socket failed.");
+        goto bailout;
+    }
+
+    // Set non-blocking operation
+    if (!setNonblocking(listen_fd_))
+        goto bailout;
+
+    struct sockaddr_in addr;
+    memset(&addr, 0, sizeof(addr));
+    addr.sin_family = AF_INET;
+    addr.sin_addr.s_addr = INADDR_ANY;
+    addr.sin_port = htons(kListenPort);
+
+    if (bind(listen_fd_, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
+        ALOGE("Bind failed.");
+        goto bailout;
+    }
+
+    if (listen(listen_fd_, 1) < 0) {
+        ALOGE("Listen failed.");
+        goto bailout;
+    }
+
+    ret = true;
+bailout:
+    if (!ret)
+        cleanupListenSocket();
+
+    return ret;
+}
+
+void DiagThread::cleanupListenSocket() {
+    if (listen_fd_ >= 0) {
+        int res;
+
+        struct linger l;
+        l.l_onoff  = 1;
+        l.l_linger = 0;
+
+        setsockopt(listen_fd_, SOL_SOCKET, SO_LINGER, &l, sizeof(l));
+        shutdown(listen_fd_, SHUT_RDWR);
+        close(listen_fd_);
+        listen_fd_ = -1;
+    }
+}
+
+void DiagThread::cleanupDataSocket() {
+    if (data_fd_ >= 0) {
+        int res;
+
+        struct linger l;
+        l.l_onoff  = 1;
+        l.l_linger = 0;
+
+        setsockopt(data_fd_, SOL_SOCKET, SO_LINGER, &l, sizeof(l));
+        shutdown(data_fd_, SHUT_RDWR);
+        close(data_fd_);
+        data_fd_ = -1;
+    }
+}
+
+void DiagThread::resetLogIDs() {
+    // Drain and discard all of the events from the kernel
+    struct local_time_debug_event events[kMaxEvents];
+    while(local_clock_->getDebugLog(events, kMaxEvents) > 0)
+        ;
+
+    {
+        Mutex::Autolock lock(&discipline_log_lock_);
+        discipline_log_.clear();
+        discipline_log_ID_ = 0;
+    }
+
+    kernel_logID_basis_known_ = false;
+}
+
+void DiagThread::pushDisciplineEvent(int64_t observed_local_time,
+                                     int64_t observed_common_time,
+                                     int64_t nominal_common_time,
+                                     int32_t total_correction,
+                                     int32_t rtt) {
+    Mutex::Autolock lock(&discipline_log_lock_);
+
+    DisciplineEventRecord evt;
+
+    evt.event_id = discipline_log_ID_++;
+
+    evt.action_local_time = local_clock_->getLocalTime();
+    common_clock_->localToCommon(evt.action_local_time,
+            &evt.action_common_time);
+
+    evt.observed_local_time  = observed_local_time;
+    evt.observed_common_time = observed_common_time;
+    evt.nominal_common_time  = nominal_common_time;
+    evt.total_correction     = total_correction;
+    evt.rtt                  = rtt;
+
+    discipline_log_.push_back(evt);
+    while (discipline_log_.size() > kMaxDisciplineLogSize)
+        discipline_log_.erase(discipline_log_.begin());
+}
+
+bool DiagThread::threadLoop() {
+    struct pollfd poll_fds[1];
+
+    if (!openListenSocket()) {
+        ALOGE("Failed to open listen socket");
+        goto bailout;
+    }
+
+    while (!exitPending()) {
+        memset(&poll_fds, 0, sizeof(poll_fds));
+
+        if (data_fd_ < 0) {
+            poll_fds[0].fd     = listen_fd_;
+            poll_fds[0].events = POLLIN;
+        } else {
+            poll_fds[0].fd     = data_fd_;
+            poll_fds[0].events = POLLRDHUP | POLLIN;
+        }
+
+        int poll_res = poll(poll_fds, NELEM(poll_fds), 50);
+        if (poll_res < 0) {
+            ALOGE("Fatal error (%d,%d) while waiting on events",
+                 poll_res, errno);
+            goto bailout;
+        }
+
+        if (exitPending())
+            break;
+
+        if (poll_fds[0].revents) {
+            if (poll_fds[0].fd == listen_fd_) {
+                data_fd_ = accept(listen_fd_, NULL, NULL);
+
+                if (data_fd_ < 0) {
+                    ALOGW("Failed accept on socket %d with err %d",
+                         listen_fd_, errno);
+                } else {
+                    if (!setNonblocking(data_fd_))
+                        cleanupDataSocket();
+                    if (!setNodelay(data_fd_))
+                        cleanupDataSocket();
+                }
+            } else
+                if (poll_fds[0].fd == data_fd_) {
+                    if (poll_fds[0].revents & POLLRDHUP) {
+                        // Connection hung up; time to clean up.
+                        cleanupDataSocket();
+                    } else
+                        if (poll_fds[0].revents & POLLIN) {
+                            uint8_t cmd;
+                            if (read(data_fd_, &cmd, sizeof(cmd)) > 0) {
+                                switch(cmd) {
+                                    case 'r':
+                                    case 'R':
+                                        resetLogIDs();
+                                        break;
+                                }
+                            }
+                        }
+                }
+        }
+
+        struct local_time_debug_event events[kMaxEvents];
+        int amt = local_clock_->getDebugLog(events, kMaxEvents);
+
+        if (amt > 0) {
+            for (int i = 0; i < amt; i++) {
+                struct local_time_debug_event& e = events[i];
+
+                if (!kernel_logID_basis_known_) {
+                    kernel_logID_basis_ = e.local_timesync_event_id;
+                    kernel_logID_basis_known_ = true;
+                }
+
+                char buf[1024];
+                int64_t common_time;
+                status_t res = common_clock_->localToCommon(e.local_time,
+                                                            &common_time);
+                snprintf(buf, sizeof(buf), "E,%lld,%lld,%lld,%d\n",
+                         e.local_timesync_event_id - kernel_logID_basis_,
+                         e.local_time,
+                         common_time,
+                         (OK == res) ? 1 : 0);
+                buf[sizeof(buf) - 1] = 0;
+
+                if (data_fd_ >= 0)
+                    write(data_fd_, buf, strlen(buf));
+            }
+        }
+
+        { // scope for autolock pattern
+            Mutex::Autolock lock(&discipline_log_lock_);
+
+            while (discipline_log_.size() > 0) {
+                char buf[1024];
+                DisciplineEventRecord& e = *discipline_log_.begin();
+                snprintf(buf, sizeof(buf),
+                         "D,%lld,%lld,%lld,%lld,%lld,%lld,%d,%d\n",
+                         e.event_id,
+                         e.action_local_time,
+                         e.action_common_time,
+                         e.observed_local_time,
+                         e.observed_common_time,
+                         e.nominal_common_time,
+                         e.total_correction,
+                         e.rtt);
+                buf[sizeof(buf) - 1] = 0;
+
+                if (data_fd_ >= 0)
+                    write(data_fd_, buf, strlen(buf));
+
+                discipline_log_.erase(discipline_log_.begin());
+            }
+        }
+    }
+
+bailout:
+    cleanupDataSocket();
+    cleanupListenSocket();
+    return false;
+}
+
+}  // namespace android
diff --git a/libs/common_time/diag_thread.h b/libs/common_time/diag_thread.h
new file mode 100644
index 0000000..c630e0d
--- /dev/null
+++ b/libs/common_time/diag_thread.h
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __DIAG_THREAD_H__
+#define __DIAG_THREAD_H__
+
+#include <utils/List.h>
+#include <utils/threads.h>
+
+namespace android {
+
+class CommonClock;
+class LocalClock;
+
+class DiagThread : public Thread {
+  public:
+    DiagThread(CommonClock* common_clock, LocalClock* local_clock);
+    ~DiagThread();
+
+    status_t      startWorkThread();
+    void          stopWorkThread();
+    virtual bool  threadLoop();
+
+    void pushDisciplineEvent(int64_t observed_local_time,
+                             int64_t observed_common_time,
+                             int64_t nominal_common_time,
+                             int32_t total_correction,
+                             int32_t rtt);
+
+  private:
+    typedef struct {
+        int64_t event_id;
+        int64_t action_local_time;
+        int64_t action_common_time;
+        int64_t observed_local_time;
+        int64_t observed_common_time;
+        int64_t nominal_common_time;
+        int32_t total_correction;
+        int32_t rtt;
+    } DisciplineEventRecord;
+
+    bool            openListenSocket();
+    void            cleanupListenSocket();
+    void            cleanupDataSocket();
+    void            resetLogIDs();
+
+    CommonClock*    common_clock_;
+    LocalClock*     local_clock_;
+    int             listen_fd_;
+    int             data_fd_;
+
+    int64_t         kernel_logID_basis_;
+    bool            kernel_logID_basis_known_;
+
+    static const size_t         kMaxDisciplineLogSize = 16;
+    Mutex                       discipline_log_lock_;
+    List<DisciplineEventRecord> discipline_log_;
+    int64_t                     discipline_log_ID_;
+};
+
+}  // namespace android
+
+#endif  //__ DIAG_THREAD_H__
diff --git a/libs/common_time/main.cpp b/libs/common_time/main.cpp
new file mode 100644
index 0000000..49eb30a
--- /dev/null
+++ b/libs/common_time/main.cpp
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * A service that exchanges time synchronization information between
+ * a master that defines a timeline and clients that follow the timeline.
+ */
+
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+
+#include <binder/IPCThreadState.h>
+#include <binder/ProcessState.h>
+
+#include "common_time_server.h"
+
+int main(int argc, char *argv[]) {
+    using namespace android;
+
+    sp<CommonTimeServer> service = new CommonTimeServer();
+    if (service == NULL)
+        return 1;
+
+    ProcessState::self()->startThreadPool();
+    service->run("CommonTimeServer", ANDROID_PRIORITY_NORMAL);
+
+    IPCThreadState::self()->joinThreadPool();
+    return 0;
+}
+
diff --git a/libs/common_time/utils.cpp b/libs/common_time/utils.cpp
new file mode 100644
index 0000000..ed2c77d
--- /dev/null
+++ b/libs/common_time/utils.cpp
@@ -0,0 +1,164 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+
+#include "utils.h"
+
+namespace android {
+
+void Timeout::setTimeout(int msec) {
+    if (msec < 0) {
+        mSystemEndTime = 0;
+        return;
+    }
+
+    mSystemEndTime = systemTime() + (static_cast<nsecs_t>(msec) * 1000000);
+}
+
+int Timeout::msecTillTimeout(nsecs_t nowTime) {
+    if (!mSystemEndTime) {
+        return -1;
+    }
+
+    if (mSystemEndTime < nowTime) {
+        return 0;
+    }
+
+    nsecs_t delta = mSystemEndTime - nowTime;
+    delta += 999999;
+    delta /= 1000000;
+    if (delta > 0x7FFFFFFF) {
+        return 0x7FFFFFFF;
+    }
+
+    return static_cast<int>(delta);
+}
+
+LogRing::LogRing(const char* header, size_t entries)
+    : mSize(entries)
+    , mWr(0)
+    , mIsFull(false)
+    , mHeader(header) {
+    mRingBuffer = new Entry[mSize];
+    if (NULL == mRingBuffer)
+        ALOGE("Failed to allocate log ring with %u entries.", mSize);
+}
+
+LogRing::~LogRing() {
+    if (NULL != mRingBuffer)
+        delete[] mRingBuffer;
+}
+
+void LogRing::log(int prio, const char* tag, const char* fmt, ...) {
+    va_list argp;
+    va_start(argp, fmt);
+    internalLog(prio, tag, fmt, argp);
+    va_end(argp);
+}
+
+void LogRing::log(const char* fmt, ...) {
+    va_list argp;
+    va_start(argp, fmt);
+    internalLog(0, NULL, fmt, argp);
+    va_end(argp);
+}
+
+void LogRing::internalLog(int prio,
+                          const char* tag,
+                          const char* fmt,
+                          va_list argp) {
+    if (NULL != mRingBuffer) {
+        Mutex::Autolock lock(&mLock);
+        String8 s(String8::formatV(fmt, argp));
+        Entry* last = NULL;
+
+        if (mIsFull || mWr)
+            last = &(mRingBuffer[(mWr + mSize - 1) % mSize]);
+
+
+        if ((NULL != last) && !last->s.compare(s)) {
+            gettimeofday(&(last->last_ts), NULL);
+            ++last->count;
+        } else {
+            gettimeofday(&mRingBuffer[mWr].first_ts, NULL);
+            mRingBuffer[mWr].last_ts = mRingBuffer[mWr].first_ts;
+            mRingBuffer[mWr].count = 1;
+            mRingBuffer[mWr].s.setTo(s);
+
+            mWr = (mWr + 1) % mSize;
+            if (!mWr)
+                mIsFull = true;
+        }
+    }
+
+    if (NULL != tag)
+        LOG_PRI_VA(prio, tag, fmt, argp);
+}
+
+void LogRing::dumpLog(int fd) {
+    if (NULL == mRingBuffer)
+        return;
+
+    Mutex::Autolock lock(&mLock);
+
+    if (!mWr && !mIsFull)
+        return;
+
+    char buf[1024];
+    int res;
+    size_t start = mIsFull ? mWr : 0;
+    size_t count = mIsFull ? mSize : mWr;
+    static const char* kTimeFmt = "%a %b %d %Y %H:%M:%S";
+
+    res = snprintf(buf, sizeof(buf), "\n%s\n", mHeader);
+    if (res > 0)
+        write(fd, buf, res);
+
+    for (size_t i = 0; i < count; ++i) {
+        struct tm t;
+        char timebuf[64];
+        char repbuf[96];
+        size_t ndx = (start + i) % mSize;
+
+        if (1 != mRingBuffer[ndx].count) {
+            localtime_r(&mRingBuffer[ndx].last_ts.tv_sec, &t);
+            strftime(timebuf, sizeof(timebuf), kTimeFmt, &t);
+            snprintf(repbuf, sizeof(repbuf),
+                    " (repeated %d times, last was %s.%03ld)",
+                     mRingBuffer[ndx].count,
+                     timebuf,
+                     mRingBuffer[ndx].last_ts.tv_usec / 1000);
+            repbuf[sizeof(repbuf) - 1] = 0;
+        } else {
+            repbuf[0] = 0;
+        }
+
+        localtime_r(&mRingBuffer[ndx].first_ts.tv_sec, &t);
+        strftime(timebuf, sizeof(timebuf), kTimeFmt, &t);
+        res = snprintf(buf, sizeof(buf), "[%2d] %s.%03ld :: %s%s\n", 
+                       i, timebuf,
+                       mRingBuffer[ndx].first_ts.tv_usec / 1000,
+                       mRingBuffer[ndx].s.string(),
+                       repbuf);
+
+        if (res > 0)
+            write(fd, buf, res);
+    }
+}
+
+}  // namespace android
diff --git a/libs/common_time/utils.h b/libs/common_time/utils.h
new file mode 100644
index 0000000..c28cf0a
--- /dev/null
+++ b/libs/common_time/utils.h
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __UTILS_H__
+#define __UTILS_H__
+
+#include <stdint.h>
+#include <unistd.h>
+
+#include <utils/String8.h>
+#include <utils/threads.h>
+#include <utils/Timers.h>
+
+namespace android {
+
+class Timeout {
+  public:
+    Timeout() : mSystemEndTime(0) { }
+
+    // Set a timeout which should occur msec milliseconds from now.
+    // Negative values will cancel any current timeout;
+    void setTimeout(int msec);
+
+    // Return the number of milliseconds until the timeout occurs, or -1 if
+    // no timeout is scheduled.
+    int msecTillTimeout(nsecs_t nowTime);
+    int msecTillTimeout() { return msecTillTimeout(systemTime()); }
+
+  private:
+    // The systemTime() at which the timeout will be complete, or 0 if no
+    // timeout is currently scheduled.
+    nsecs_t mSystemEndTime;
+};
+
+class LogRing {
+  public:
+    LogRing(const char* header, size_t entries);
+    ~LogRing();
+
+    // Send a log message to logcat as well as storing it in the ring buffer.
+    void log(int prio, const char* tag, const char* fmt, ...);
+
+    // Add a log message the ring buffer, do not send the message to logcat.
+    void log(const char* fmt, ...);
+
+    // Dump the log to an fd (dumpsys style)
+    void dumpLog(int fd);
+
+  private:
+    class Entry {
+      public:
+        uint32_t count;
+        struct timeval first_ts;
+        struct timeval last_ts;
+        String8 s;
+    };
+
+    Mutex  mLock;
+    Entry* mRingBuffer;
+    size_t mSize;
+    size_t mWr;
+    bool   mIsFull;
+    const char* mHeader;
+
+    void internalLog(int prio, const char* tag, const char* fmt, va_list va);
+};
+
+}  // namespace android
+
+#endif  // __UTILS_H__