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 #if defined(NETD_CLIENT_DEBUGGABLE_BUILD)
35 constexpr bool isBuildDebuggable = true;
36 #else
37 constexpr bool isBuildDebuggable = false;
38 #endif
39
isOverriddenBy(const char * name)40 bool isOverriddenBy(const char *name) {
41 return isBuildDebuggable && getenv(name);
42 }
43
commandHasFd(int cmdId)44 bool commandHasFd(int cmdId) {
45 return (cmdId != FwmarkCommand::QUERY_USER_ACCESS) &&
46 (cmdId != FwmarkCommand::SET_COUNTERSET) &&
47 (cmdId != FwmarkCommand::DELETE_TAGDATA);
48 }
49
50 } // namespace
51
shouldSetFwmark(int family)52 bool FwmarkClient::shouldSetFwmark(int family) {
53 if (isOverriddenBy(ANDROID_NO_USE_FWMARK_CLIENT)) {
54 return false;
55 }
56 return family == AF_INET || family == AF_INET6;
57 }
58
shouldReportConnectComplete(int family)59 bool FwmarkClient::shouldReportConnectComplete(int family) {
60 if (isOverriddenBy(ANDROID_FWMARK_METRICS_ONLY)) {
61 return false;
62 }
63 return shouldSetFwmark(family);
64 }
65
FwmarkClient()66 FwmarkClient::FwmarkClient() : mChannel(-1) {
67 }
68
~FwmarkClient()69 FwmarkClient::~FwmarkClient() {
70 if (mChannel >= 0) {
71 close(mChannel);
72 }
73 }
74
send(FwmarkCommand * data,int fd,FwmarkConnectInfo * connectInfo)75 int FwmarkClient::send(FwmarkCommand* data, int fd, FwmarkConnectInfo* connectInfo) {
76 mChannel = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
77 if (mChannel == -1) {
78 return -errno;
79 }
80
81 if (TEMP_FAILURE_RETRY(connect(mChannel, reinterpret_cast<const sockaddr*>(&FWMARK_SERVER_PATH),
82 sizeof(FWMARK_SERVER_PATH))) == -1) {
83 // If we are unable to connect to the fwmark server, assume there's no error. This protects
84 // against future changes if the fwmark server goes away.
85 // TODO: This means that fd will very likely be misrouted. See if we can delete this in a
86 // separate CL.
87 return 0;
88 }
89
90 iovec iov[2] = {
91 { data, sizeof(*data) },
92 { connectInfo, (connectInfo ? sizeof(*connectInfo) : 0) },
93 };
94 msghdr message;
95 memset(&message, 0, sizeof(message));
96 message.msg_iov = iov;
97 message.msg_iovlen = ARRAY_SIZE(iov);
98
99 union {
100 cmsghdr cmh;
101 char cmsg[CMSG_SPACE(sizeof(fd))];
102 } cmsgu;
103
104 if (commandHasFd(data->cmdId)) {
105 memset(cmsgu.cmsg, 0, sizeof(cmsgu.cmsg));
106 message.msg_control = cmsgu.cmsg;
107 message.msg_controllen = sizeof(cmsgu.cmsg);
108
109 cmsghdr* const cmsgh = CMSG_FIRSTHDR(&message);
110 cmsgh->cmsg_len = CMSG_LEN(sizeof(fd));
111 cmsgh->cmsg_level = SOL_SOCKET;
112 cmsgh->cmsg_type = SCM_RIGHTS;
113 memcpy(CMSG_DATA(cmsgh), &fd, sizeof(fd));
114 }
115
116 if (TEMP_FAILURE_RETRY(sendmsg(mChannel, &message, 0)) == -1) {
117 return -errno;
118 }
119
120 int error = 0;
121
122 if (TEMP_FAILURE_RETRY(recv(mChannel, &error, sizeof(error), 0)) == -1) {
123 return -errno;
124 }
125
126 return error;
127 }
128