1 /*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "FwmarkClient.h"
18
19 #include <stdlib.h>
20 #include <sys/socket.h>
21 #include <sys/un.h>
22 #include <unistd.h>
23
24 namespace {
25
26 const sockaddr_un FWMARK_SERVER_PATH = {AF_UNIX, "/dev/socket/fwmarkd"};
27
28 } // namespace
29
shouldSetFwmark(int family)30 bool FwmarkClient::shouldSetFwmark(int family) {
31 return (family == AF_INET || family == AF_INET6) && !getenv("ANDROID_NO_USE_FWMARK_CLIENT");
32 }
33
FwmarkClient()34 FwmarkClient::FwmarkClient() : mChannel(-1) {
35 }
36
~FwmarkClient()37 FwmarkClient::~FwmarkClient() {
38 if (mChannel >= 0) {
39 close(mChannel);
40 }
41 }
42
send(void * data,size_t len,int fd)43 int FwmarkClient::send(void* data, size_t len, int fd) {
44 mChannel = socket(AF_UNIX, SOCK_STREAM, 0);
45 if (mChannel == -1) {
46 return -errno;
47 }
48
49 if (TEMP_FAILURE_RETRY(connect(mChannel, reinterpret_cast<const sockaddr*>(&FWMARK_SERVER_PATH),
50 sizeof(FWMARK_SERVER_PATH))) == -1) {
51 // If we are unable to connect to the fwmark server, assume there's no error. This protects
52 // against future changes if the fwmark server goes away.
53 return 0;
54 }
55
56 iovec iov;
57 iov.iov_base = data;
58 iov.iov_len = len;
59
60 msghdr message;
61 memset(&message, 0, sizeof(message));
62 message.msg_iov = &iov;
63 message.msg_iovlen = 1;
64
65 union {
66 cmsghdr cmh;
67 char cmsg[CMSG_SPACE(sizeof(fd))];
68 } cmsgu;
69
70 memset(cmsgu.cmsg, 0, sizeof(cmsgu.cmsg));
71 message.msg_control = cmsgu.cmsg;
72 message.msg_controllen = sizeof(cmsgu.cmsg);
73
74 cmsghdr* const cmsgh = CMSG_FIRSTHDR(&message);
75 cmsgh->cmsg_len = CMSG_LEN(sizeof(fd));
76 cmsgh->cmsg_level = SOL_SOCKET;
77 cmsgh->cmsg_type = SCM_RIGHTS;
78 memcpy(CMSG_DATA(cmsgh), &fd, sizeof(fd));
79
80 if (TEMP_FAILURE_RETRY(sendmsg(mChannel, &message, 0)) == -1) {
81 return -errno;
82 }
83
84 int error = 0;
85
86 if (TEMP_FAILURE_RETRY(recv(mChannel, &error, sizeof(error), 0)) == -1) {
87 return -errno;
88 }
89
90 return error;
91 }
92