1 /*
2 * Copyright (C) 2012 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 <stdlib.h>
18 #include <errno.h>
19 #include <fcntl.h>
20 #include <string.h>
21 #include <dirent.h>
22
23 #include <dlfcn.h>
24
25 #include <sys/socket.h>
26 #include <sys/stat.h>
27 #include <sys/ioctl.h>
28 #include <sys/types.h>
29
30 #include <netinet/in.h>
31 #include <arpa/inet.h>
32
33 #define LOG_TAG "InterfaceController"
34 #include <cutils/log.h>
35 #include <netutils/ifc.h>
36 #include <private/android_filesystem_config.h>
37
38 #include "NetdConstants.h"
39
40 #include "InterfaceController.h"
41
42 char if_cmd_lib_file_name[] = "/system/lib/libnetcmdiface.so";
43 char set_cmd_func_name[] = "net_iface_send_command";
44 char set_cmd_init_func_name[] = "net_iface_send_command_init";
45 char set_cmd_fini_func_name[] = "net_iface_send_command_fini";
46
47 const char ipv6_proc_path[] = "/proc/sys/net/ipv6/conf";
48
49 const char sys_net_path[] = "/sys/class/net";
50
InterfaceController()51 InterfaceController::InterfaceController()
52 : sendCommand_(NULL) {
53 // Initial IPv6 settings.
54 // By default, accept_ra is set to 1 (accept RAs unless forwarding is on) on all interfaces.
55 // This causes RAs to work or not work based on whether forwarding is on, and causes routes
56 // learned from RAs to go away when forwarding is turned on. Make this behaviour predictable
57 // by always setting accept_ra to 2.
58 setAcceptRA("2");
59
60 libh_ = dlopen(if_cmd_lib_file_name, RTLD_NOW | RTLD_LOCAL);
61 if (libh_ == NULL) {
62 const char *err_str = dlerror();
63 ALOGW("Warning (%s) while opening the net interface command library", err_str ? err_str : "unknown");
64 } else {
65 sendCommandInit_ = (int (*)(void))dlsym(libh_, set_cmd_init_func_name);
66 if (sendCommandInit_ == NULL) {
67 const char *err_str = dlerror();
68 ALOGW("Error (%s) while searching for the interface command init function", err_str ? err_str : "unknown");
69 } else if (sendCommandInit_()) {
70 ALOGE("Can't init the interface command API");
71 return;
72 }
73 sendCommandFini_ = (int (*)(void))dlsym(libh_, set_cmd_fini_func_name);
74 if (sendCommandFini_ == NULL) {
75 const char *err_str = dlerror();
76 ALOGW("Error (%s) while searching for the interface command fini function", err_str ? err_str : "unknown");
77 }
78 sendCommand_ = (int (*)(int, char **, char **))dlsym(libh_, set_cmd_func_name);
79 if (sendCommand_ == NULL) {
80 const char *err_str = dlerror();
81 ALOGE("Error (%s) while searching for the interface command function", err_str ? err_str : "unknown");
82 return;
83 }
84 }
85 }
86
~InterfaceController()87 InterfaceController::~InterfaceController() {
88 if (sendCommandFini_) {
89 if (sendCommandFini_()) {
90 ALOGE("Can't shutdown the interface command API");
91 }
92 }
93 if (libh_) {
94 int err = dlclose(libh_);
95 if (err) {
96 const char *err_str = dlerror();
97 ALOGE("Error (%s) while closing the net interface command library", err_str ? err_str : "unknown");
98 }
99 }
100 }
101
102 /*
103 * Arguments:
104 * argv[2] - wlan interface
105 * argv[3] - command
106 * argv[4] - argument
107 * rbuf - returned buffer
108 */
interfaceCommand(int argc,char * argv[],char ** rbuf)109 int InterfaceController::interfaceCommand(int argc, char *argv[], char **rbuf) {
110 int ret = -ENOSYS;
111 if (sendCommand_)
112 ret = sendCommand_(argc, argv, rbuf);
113
114 return ret;
115 }
116
writeIPv6ProcPath(const char * interface,const char * setting,const char * value)117 int InterfaceController::writeIPv6ProcPath(const char *interface, const char *setting, const char *value) {
118 char *path;
119 asprintf(&path, "%s/%s/%s", ipv6_proc_path, interface, setting);
120 int success = writeFile(path, value, strlen(value));
121 free(path);
122 return success;
123 }
124
setEnableIPv6(const char * interface,const int on)125 int InterfaceController::setEnableIPv6(const char *interface, const int on) {
126 // When disable_ipv6 changes from 1 to 0, the kernel starts autoconf.
127 // When disable_ipv6 changes from 0 to 1, the kernel clears all autoconf
128 // addresses and routes and disables IPv6 on the interface.
129 const char *disable_ipv6 = on ? "0" : "1";
130 return writeIPv6ProcPath(interface, "disable_ipv6", disable_ipv6);
131 }
132
setIPv6PrivacyExtensions(const char * interface,const int on)133 int InterfaceController::setIPv6PrivacyExtensions(const char *interface, const int on) {
134 // 0: disable IPv6 privacy addresses
135 // 0: enable IPv6 privacy addresses and prefer them over non-privacy ones.
136 return writeIPv6ProcPath(interface, "use_tempaddr", on ? "2" : "0");
137 }
138
isInterfaceName(const char * name)139 int InterfaceController::isInterfaceName(const char *name) {
140 return strcmp(name, ".") &&
141 strcmp(name, "..") &&
142 strcmp(name, "default") &&
143 strcmp(name, "all");
144 }
145
setAcceptRA(const char * value)146 int InterfaceController::setAcceptRA(const char *value) {
147 // Set the default value, which is used by any interfaces that are created in the future.
148 writeIPv6ProcPath("default", "accept_ra", value);
149
150 // Set the value on all the interfaces.
151 DIR *dir = opendir(ipv6_proc_path);
152 if (!dir) {
153 ALOGE("Can't list %s: %s", ipv6_proc_path, strerror(errno));
154 return -errno;
155 }
156 struct dirent *d;
157 while((d = readdir(dir)) != NULL) {
158 if (d->d_type == DT_DIR && isInterfaceName(d->d_name)) {
159 if (writeIPv6ProcPath(d->d_name, "accept_ra", value) < 0) {
160 ALOGE("Can't write to %s/%s/accept_ra: %s", ipv6_proc_path,
161 d->d_name, strerror(errno));
162 }
163 }
164 }
165 closedir(dir);
166 return 0;
167 }
168
getMtu(const char * interface,int * mtu)169 int InterfaceController::getMtu(const char *interface, int *mtu)
170 {
171 char buf[16];
172 int size = sizeof(buf);
173 char *path;
174 asprintf(&path, "%s/%s/mtu", sys_net_path, interface);
175 int success = readFile(path, buf, &size);
176 if (!success && mtu)
177 *mtu = atoi(buf);
178 free(path);
179 return success;
180
181 }
182
setMtu(const char * interface,const char * mtu)183 int InterfaceController::setMtu(const char *interface, const char *mtu)
184 {
185 char *path;
186 asprintf(&path, "%s/%s/mtu", sys_net_path, interface);
187 int success = writeFile(path, mtu, strlen(mtu));
188 free(path);
189 return success;
190 }
191