FwmarkClient.cpp revision 18070184759f91e8b3dd9e4f37a1977deee6712d 
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
28namespace {
29
30const sockaddr_un FWMARK_SERVER_PATH = {AF_UNIX, "/dev/socket/fwmarkd"};
31
32}  // namespace
33
34bool FwmarkClient::shouldSetFwmark(int family) {
35    return (family == AF_INET || family == AF_INET6) && !getenv("ANDROID_NO_USE_FWMARK_CLIENT");
36}
37
38FwmarkClient::FwmarkClient() : mChannel(-1) {
39}
40
41FwmarkClient::~FwmarkClient() {
42    if (mChannel >= 0) {
43        close(mChannel);
44    }
45}
46
47int __attribute__((optnone)) FwmarkClient::send(FwmarkCommand* data, int fd) {
48    mChannel = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
49    if (mChannel == -1) {
50        return -errno;
51    }
52
53    if (TEMP_FAILURE_RETRY(connect(mChannel, reinterpret_cast<const sockaddr*>(&FWMARK_SERVER_PATH),
54                                   sizeof(FWMARK_SERVER_PATH))) == -1) {
55        // If we are unable to connect to the fwmark server, assume there's no error. This protects
56        // against future changes if the fwmark server goes away.
57        return 0;
58    }
59
60    iovec iov;
61    iov.iov_base = data;
62    iov.iov_len = sizeof(*data);
63
64    msghdr message;
65    memset(&message, 0, sizeof(message));
66    message.msg_iov = &iov;
67    message.msg_iovlen = 1;
68
69    if (data->cmdId != FwmarkCommand::QUERY_USER_ACCESS) {
70        union {
71            cmsghdr cmh;
72            char cmsg[CMSG_SPACE(sizeof(fd))];
73        } cmsgu;
74
75        memset(cmsgu.cmsg, 0, sizeof(cmsgu.cmsg));
76        message.msg_control = cmsgu.cmsg;
77        message.msg_controllen = sizeof(cmsgu.cmsg);
78
79        cmsghdr* const cmsgh = CMSG_FIRSTHDR(&message);
80        cmsgh->cmsg_len = CMSG_LEN(sizeof(fd));
81        cmsgh->cmsg_level = SOL_SOCKET;
82        cmsgh->cmsg_type = SCM_RIGHTS;
83        memcpy(CMSG_DATA(cmsgh), &fd, sizeof(fd));
84    }
85
86    if (TEMP_FAILURE_RETRY(sendmsg(mChannel, &message, 0)) == -1) {
87        return -errno;
88    }
89
90    int error = 0;
91
92    if (TEMP_FAILURE_RETRY(recv(mChannel, &error, sizeof(error), 0)) == -1) {
93        return -errno;
94    }
95
96    return error;
97}
98