1 files changed, 217 insertions, 0 deletions
diff --git a/luni/src/main/native/ifaddrs-android.cpp b/luni/src/main/native/ifaddrs-android.cpp
new file mode 100644
index 0000000..4193bdf
--- /dev/null
+++ b/luni/src/main/native/ifaddrs-android.cpp
@@ -0,0 +1,217 @@
+/*
+ * Copyright (C) 2009 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.
+ */
+
+#ifdef HAVE_ANDROID_OS
+
+#include "ifaddrs-android.h"
+
+#include <arpa/inet.h>
+#include <cstring>
+#include <errno.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <new>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <stdio.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include "ScopedFd.h"
+#include "UniquePtr.h"
+
+ifaddrs::ifaddrs(ifaddrs* next, sockaddr* ifa_addr, sockaddr* ifa_netmask)
+: ifa_next(next), ifa_name(NULL), ifa_flags(0), ifa_addr(ifa_addr), ifa_netmask(ifa_netmask)
+{
+}
+
+ifaddrs::~ifaddrs() {
+    delete ifa_next;
+    delete[] ifa_name;
+    delete ifa_addr;
+    delete ifa_netmask;
+}
+
+static bool sendNetlinkMessage(int fd, const void* data, size_t byteCount) {
+    ssize_t sentByteCount = TEMP_FAILURE_RETRY(send(fd, data, byteCount, 0));
+    return (sentByteCount == static_cast<ssize_t>(byteCount));
+}
+
+static ssize_t recvNetlinkMessage(int fd, char* buf, size_t byteCount) {
+    return TEMP_FAILURE_RETRY(recv(fd, buf, byteCount, 0));
+}
+
+// Returns a pointer to the first byte in the address data (which is
+// stored in network byte order).
+static uint8_t* sockaddrBytes(int family, sockaddr_storage* ss) {
+    if (family == AF_INET) {
+        sockaddr_in* ss4 = reinterpret_cast<sockaddr_in*>(ss);
+        return reinterpret_cast<uint8_t*>(&ss4->sin_addr);
+    } else if (family == AF_INET6) {
+        sockaddr_in6* ss6 = reinterpret_cast<sockaddr_in6*>(ss);
+        return reinterpret_cast<uint8_t*>(&ss6->sin6_addr);
+    }
+    return NULL;
+}
+
+// Netlink gives us the address family in the header, and the
+// sockaddr_in or sockaddr_in6 bytes as the payload. We need to
+// stitch the two bits together into the sockaddr that's part of
+// our portable interface.
+static sockaddr* toSocketAddress(int family, void* data, size_t byteCount) {
+    // Set the address proper...
+    sockaddr_storage* ss = new sockaddr_storage;
+    memset(ss, 0, sizeof(*ss));
+    ss->ss_family = family;
+    uint8_t* dst = sockaddrBytes(family, ss);
+    memcpy(dst, data, byteCount);
+    return reinterpret_cast<sockaddr*>(ss);
+}
+
+// Netlink gives us the prefix length as a bit count. We need to turn
+// that into a BSD-compatible netmask represented by a sockaddr*.
+static sockaddr* toNetmask(int family, size_t prefixLength) {
+    // ...and work out the netmask from the prefix length.
+    sockaddr_storage* ss = new sockaddr_storage;
+    memset(ss, 0, sizeof(*ss));
+    ss->ss_family = family;
+    uint8_t* dst = sockaddrBytes(family, ss);
+    memset(dst, 0xff, prefixLength / 8);
+    if ((prefixLength % 8) != 0) {
+        dst[prefixLength/8] = (0xff << (8 - (prefixLength % 8)));
+    }
+    return reinterpret_cast<sockaddr*>(ss);
+}
+
+// Sadly, we can't keep the interface index for portability with BSD.
+// We'll have to keep the name instead, and re-query the index when
+// we need it later.
+static bool setNameAndFlagsByIndex(ifaddrs* ifa, int interfaceIndex) {
+    // Get the name.
+    char buf[IFNAMSIZ];
+    char* name = if_indextoname(interfaceIndex, buf);
+    if (name == NULL) {
+        return false;
+    }
+    ifa->ifa_name = new char[strlen(name) + 1];
+    strcpy(ifa->ifa_name, name);
+
+    // Get the flags.
+    ScopedFd fd(socket(AF_INET, SOCK_DGRAM, 0));
+    if (fd.get() == -1) {
+        return false;
+    }
+    ifreq ifr;
+    memset(&ifr, 0, sizeof(ifr));
+    strcpy(ifr.ifr_name, name);
+    int rc = ioctl(fd.get(), SIOCGIFFLAGS, &ifr);
+    if (rc == -1) {
+        return false;
+    }
+    ifa->ifa_flags = ifr.ifr_flags;
+    return true;
+}
+
+// Source-compatible with the BSD function.
+int getifaddrs(ifaddrs** result) {
+    // Simplify cleanup for callers.
+    *result = NULL;
+
+    // Create a netlink socket.
+    ScopedFd fd(socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE));
+    if (fd.get() < 0) {
+        return -1;
+    }
+
+    // Ask for the address information.
+    struct {
+        nlmsghdr netlinkHeader;
+        ifaddrmsg msg;
+    } request;
+    memset(&request, 0, sizeof(request));
+    request.netlinkHeader.nlmsg_flags = NLM_F_ROOT | NLM_F_REQUEST | NLM_F_MATCH;
+    request.netlinkHeader.nlmsg_type = RTM_GETADDR;
+    request.netlinkHeader.nlmsg_len = NLMSG_ALIGN(NLMSG_LENGTH(sizeof(request)));
+    request.msg.ifa_family = AF_UNSPEC; // All families.
+    request.msg.ifa_index = 0; // All interfaces.
+    if (!sendNetlinkMessage(fd.get(), &request, request.netlinkHeader.nlmsg_len)) {
+        return -1;
+    }
+
+    // Read the responses.
+    const size_t bufferSize = 65536;
+    UniquePtr<char[]> buf(new char[bufferSize]);
+    ssize_t bytesRead;
+    while ((bytesRead  = recvNetlinkMessage(fd.get(), &buf[0], bufferSize)) > 0) {
+        nlmsghdr* hdr = reinterpret_cast<nlmsghdr*>(&buf[0]);
+        for (; NLMSG_OK(hdr, (size_t)bytesRead); hdr = NLMSG_NEXT(hdr, bytesRead)) {
+            switch (hdr->nlmsg_type) {
+            case NLMSG_DONE:
+                return 0;
+            case NLMSG_ERROR:
+                return -1;
+            case RTM_NEWADDR:
+                {
+                    // A given RTM_NEWADDR payload may contain multiple addresses. The while loop
+                    // below iterates through them. These locals contain the best address we've
+                    // seen so far.
+                    int ifa_index = -1;
+                    UniquePtr<sockaddr> ifa_addr;
+                    UniquePtr<sockaddr> ifa_netmask;
+
+                    ifaddrmsg* address = reinterpret_cast<ifaddrmsg*>(NLMSG_DATA(hdr));
+                    rtattr* rta = IFA_RTA(address);
+                    size_t ifaPayloadLength = IFA_PAYLOAD(hdr);
+                    while (RTA_OK(rta, ifaPayloadLength)) {
+                        // We can't just use IFA_ADDRESS because it's the destination address for
+                        // a point-to-point interface; we can't just use IFA_LOCAL because we don't
+                        // always have it. That is: we want IFA_LOCAL if we get it, but IFA_ADDRESS
+                        // otherwise. We take advantage of the fact that the kernel returns
+                        // IFA_LOCAL (if available) second.
+                        if (rta->rta_type == IFA_LOCAL || rta->rta_type == IFA_ADDRESS) {
+                            int family = address->ifa_family;
+                            if (family == AF_INET || family == AF_INET6) {
+                                ifa_index = address->ifa_index;
+                                ifa_addr.reset(toSocketAddress(family, RTA_DATA(rta), RTA_PAYLOAD(rta)));
+                                ifa_netmask.reset(toNetmask(family, address->ifa_prefixlen));
+                            }
+                        }
+                        rta = RTA_NEXT(rta, ifaPayloadLength);
+                    }
+
+                    // Did we get a usable address? If so, thread it on our list.
+                    if (ifa_index != -1) {
+                        *result = new ifaddrs(*result, ifa_addr.release(), ifa_netmask.release());
+                        if (!setNameAndFlagsByIndex(*result, ifa_index)) {
+                            return -1;
+                        }
+                    }
+                }
+                break;
+            }
+        }
+    }
+    // We only get here if recv fails before we see a NLMSG_DONE.
+    return -1;
+}
+
+// Source-compatible with the BSD function.
+void freeifaddrs(ifaddrs* addresses) {
+    delete addresses;
+}
+
+#endif