1 /*
2 * Copyright (C) 2016 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 "wifi_system/interface_tool.h"
18
19 #include <net/if_arp.h>
20 #include <netinet/in.h>
21 #include <sys/socket.h>
22 /* We need linux/if.h for flags like IFF_UP. Sadly, it forward declares
23 struct sockaddr and must be included after sys/socket.h. */
24 #include <linux/if.h>
25
26
27 #include <android-base/logging.h>
28 #include <android-base/unique_fd.h>
29
30 namespace android {
31 namespace wifi_system {
32 namespace {
33
34 const char kWlan0InterfaceName[] = "wlan0";
35
GetIfState(const char * if_name,int sock,struct ifreq * ifr)36 bool GetIfState(const char* if_name, int sock, struct ifreq* ifr) {
37 memset(ifr, 0, sizeof(*ifr));
38 if (strlcpy(ifr->ifr_name, if_name, sizeof(ifr->ifr_name)) >=
39 sizeof(ifr->ifr_name)) {
40 LOG(ERROR) << "Interface name is too long: " << if_name;
41 return false;
42 }
43
44 if (TEMP_FAILURE_RETRY(ioctl(sock, SIOCGIFFLAGS, ifr)) != 0) {
45 LOG(ERROR) << "Could not read interface state for " << if_name
46 << " (" << strerror(errno) << ")";
47 return false;
48 }
49
50 return true;
51 }
52
53 } // namespace
54
GetUpState(const char * if_name)55 bool InterfaceTool::GetUpState(const char* if_name) {
56 base::unique_fd sock(socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0));
57 if (sock.get() < 0) {
58 LOG(ERROR) << "Failed to open socket to set up/down state ("
59 << strerror(errno) << ")";
60 return false;
61 }
62
63 struct ifreq ifr;
64 if (!GetIfState(if_name, sock.get(), &ifr)) {
65 return false; // logging done internally
66 }
67
68 return ifr.ifr_flags & IFF_UP;
69 }
70
SetUpState(const char * if_name,bool request_up)71 bool InterfaceTool::SetUpState(const char* if_name, bool request_up) {
72 base::unique_fd sock(socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0));
73 if (sock.get() < 0) {
74 LOG(ERROR) << "Failed to open socket to set up/down state ("
75 << strerror(errno) << ")";
76 return false;
77 }
78
79 struct ifreq ifr;
80 if (!GetIfState(if_name, sock.get(), &ifr)) {
81 return false; // logging done internally
82 }
83
84 const bool currently_up = ifr.ifr_flags & IFF_UP;
85 if (currently_up == request_up) {
86 return true;
87 }
88
89 if (request_up) {
90 ifr.ifr_flags |= IFF_UP;
91 } else {
92 ifr.ifr_flags &= ~IFF_UP;
93 }
94
95 if (TEMP_FAILURE_RETRY(ioctl(sock.get(), SIOCSIFFLAGS, &ifr)) != 0) {
96 LOG(ERROR) << "Could not set interface flags for " << if_name
97 << " (" << strerror(errno) << ")";
98 return false;
99 }
100
101 return true;
102 }
103
SetWifiUpState(bool request_up)104 bool InterfaceTool::SetWifiUpState(bool request_up) {
105 return SetUpState(kWlan0InterfaceName, request_up);
106 }
107
SetMacAddress(const char * if_name,const std::array<uint8_t,ETH_ALEN> & new_address)108 bool InterfaceTool::SetMacAddress(const char* if_name,
109 const std::array<uint8_t, ETH_ALEN>& new_address) {
110 struct ifreq ifr;
111 static_assert(ETH_ALEN <= sizeof(ifr.ifr_hwaddr.sa_data),
112 "new address is too long");
113
114 base::unique_fd sock(socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0));
115 if (sock.get() < 0) {
116 LOG(ERROR) << "Failed to open socket to set MAC address ("
117 << strerror(errno) << ")";
118 return false;
119 }
120
121 if (!GetIfState(if_name, sock.get(), &ifr)) {
122 return false; // logging done internally
123 }
124
125 memset(&ifr.ifr_hwaddr, 0, sizeof(ifr.ifr_hwaddr));
126 ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
127 memcpy(ifr.ifr_hwaddr.sa_data, new_address.data(), new_address.size());
128 if (TEMP_FAILURE_RETRY(ioctl(sock.get(), SIOCSIFHWADDR, &ifr)) != 0) {
129 LOG(ERROR) << "Could not set interface MAC address for " << if_name
130 << " (" << strerror(errno) << ")";
131 return false;
132 }
133
134 return true;
135 }
136
137 } // namespace wifi_system
138 } // namespace android
139