1 files changed, 96 insertions, 0 deletions
diff --git a/libnetd_client/FwmarkClient.cpp b/libnetd_client/FwmarkClient.cpp
new file mode 100644
index 0000000..e360b4e
--- /dev/null
+++ b/libnetd_client/FwmarkClient.cpp
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2014 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 "FwmarkClient.h"
+
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+namespace {
+
+const sockaddr_un FWMARK_SERVER_PATH = {AF_UNIX, "/dev/socket/fwmarkd"};
+
+}  // namespace
+
+bool FwmarkClient::shouldSetFwmark(int sockfd, const sockaddr* addr) {
+    return sockfd >= 0 && addr && (addr->sa_family == AF_INET || addr->sa_family == AF_INET6) &&
+           !getenv("ANDROID_NO_USE_FWMARK_CLIENT");
+}
+
+FwmarkClient::FwmarkClient() : mChannel(-1) {
+}
+
+FwmarkClient::~FwmarkClient() {
+    if (mChannel >= 0) {
+        // We don't care about errors while closing the channel, so restore any previous error.
+        int error = errno;
+        close(mChannel);
+        errno = error;
+    }
+}
+
+bool FwmarkClient::send(void* data, size_t len, int fd) {
+    mChannel = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (mChannel == -1) {
+        return false;
+    }
+
+    if (TEMP_FAILURE_RETRY(connect(mChannel, reinterpret_cast<const sockaddr*>(&FWMARK_SERVER_PATH),
+                                   sizeof(FWMARK_SERVER_PATH))) == -1) {
+        // If we are unable to connect to the fwmark server, assume there's no error. This protects
+        // against future changes if the fwmark server goes away.
+        errno = 0;
+        return true;
+    }
+
+    iovec iov;
+    iov.iov_base = data;
+    iov.iov_len = len;
+
+    msghdr message;
+    memset(&message, 0, sizeof(message));
+    message.msg_iov = &iov;
+    message.msg_iovlen = 1;
+
+    union {
+        cmsghdr cmh;
+        char cmsg[CMSG_SPACE(sizeof(fd))];
+    } cmsgu;
+
+    memset(cmsgu.cmsg, 0, sizeof(cmsgu.cmsg));
+    message.msg_control = cmsgu.cmsg;
+    message.msg_controllen = sizeof(cmsgu.cmsg);
+
+    cmsghdr* const cmsgh = CMSG_FIRSTHDR(&message);
+    cmsgh->cmsg_len = CMSG_LEN(sizeof(fd));
+    cmsgh->cmsg_level = SOL_SOCKET;
+    cmsgh->cmsg_type = SCM_RIGHTS;
+    memcpy(CMSG_DATA(cmsgh), &fd, sizeof(fd));
+
+    if (TEMP_FAILURE_RETRY(sendmsg(mChannel, &message, 0)) == -1) {
+        return false;
+    }
+
+    int error = 0;
+    if (TEMP_FAILURE_RETRY(recv(mChannel, &error, sizeof(error), 0)) == -1) {
+        return false;
+    }
+
+    errno = error;
+    return !error;
+}