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 "FwmarkCommand.h"
20
21 #include <errno.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <sys/socket.h>
25 #include <sys/un.h>
26 #include <unistd.h>
27
28 #define ARRAY_SIZE(a) (sizeof(a) / sizeof(*(a)))
29
30 namespace {
31
32 const sockaddr_un FWMARK_SERVER_PATH = {AF_UNIX, "/dev/socket/fwmarkd"};
33
34 } // namespace
35
shouldSetFwmark(int family)36 bool FwmarkClient::shouldSetFwmark(int family) {
37 return (family == AF_INET || family == AF_INET6) && !getenv(ANDROID_NO_USE_FWMARK_CLIENT);
38 }
39
shouldReportConnectComplete(int family)40 bool FwmarkClient::shouldReportConnectComplete(int family) {
41 // TODO: put getenv(ANDROID_FWMARK_METRICS_ONLY) behind the ro.debuggable system property
42 // or else an app can evade connect logging just by setting the env variable
43 return shouldSetFwmark(family) && !getenv(ANDROID_FWMARK_METRICS_ONLY);
44 }
45
FwmarkClient()46 FwmarkClient::FwmarkClient() : mChannel(-1) {
47 }
48
~FwmarkClient()49 FwmarkClient::~FwmarkClient() {
50 if (mChannel >= 0) {
51 close(mChannel);
52 }
53 }
54
send(FwmarkCommand * data,int fd,FwmarkConnectInfo * connectInfo)55 int FwmarkClient::send(FwmarkCommand* data, int fd, FwmarkConnectInfo* connectInfo) {
56 mChannel = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
57 if (mChannel == -1) {
58 return -errno;
59 }
60
61 if (TEMP_FAILURE_RETRY(connect(mChannel, reinterpret_cast<const sockaddr*>(&FWMARK_SERVER_PATH),
62 sizeof(FWMARK_SERVER_PATH))) == -1) {
63 // If we are unable to connect to the fwmark server, assume there's no error. This protects
64 // against future changes if the fwmark server goes away.
65 return 0;
66 }
67
68 iovec iov[2] = {
69 { data, sizeof(*data) },
70 { connectInfo, (connectInfo ? sizeof(*connectInfo) : 0) },
71 };
72 msghdr message;
73 memset(&message, 0, sizeof(message));
74 message.msg_iov = iov;
75 message.msg_iovlen = ARRAY_SIZE(iov);
76
77 union {
78 cmsghdr cmh;
79 char cmsg[CMSG_SPACE(sizeof(fd))];
80 } cmsgu;
81
82 if (data->cmdId != FwmarkCommand::QUERY_USER_ACCESS) {
83 memset(cmsgu.cmsg, 0, sizeof(cmsgu.cmsg));
84 message.msg_control = cmsgu.cmsg;
85 message.msg_controllen = sizeof(cmsgu.cmsg);
86
87 cmsghdr* const cmsgh = CMSG_FIRSTHDR(&message);
88 cmsgh->cmsg_len = CMSG_LEN(sizeof(fd));
89 cmsgh->cmsg_level = SOL_SOCKET;
90 cmsgh->cmsg_type = SCM_RIGHTS;
91 memcpy(CMSG_DATA(cmsgh), &fd, sizeof(fd));
92 }
93
94 if (TEMP_FAILURE_RETRY(sendmsg(mChannel, &message, 0)) == -1) {
95 return -errno;
96 }
97
98 int error = 0;
99
100 if (TEMP_FAILURE_RETRY(recv(mChannel, &error, sizeof(error), 0)) == -1) {
101 return -errno;
102 }
103
104 return error;
105 }
106