InterfaceController.cpp revision 69261cb65186e27dfbdc1e3eec796437f9968ff9 
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#include "RouteController.h"
42
43char if_cmd_lib_file_name[] = "libnetcmdiface.so";
44char set_cmd_func_name[] = "net_iface_send_command";
45char set_cmd_init_func_name[] = "net_iface_send_command_init";
46char set_cmd_fini_func_name[] = "net_iface_send_command_fini";
47
48const char ipv6_proc_path[] = "/proc/sys/net/ipv6/conf";
49
50const char sys_net_path[] = "/sys/class/net";
51
52InterfaceController::InterfaceController()
53	: sendCommand_(NULL) {
54	// Initial IPv6 settings.
55	// By default, accept_ra is set to 1 (accept RAs unless forwarding is on) on all interfaces.
56	// This causes RAs to work or not work based on whether forwarding is on, and causes routes
57	// learned from RAs to go away when forwarding is turned on. Make this behaviour predictable
58	// by always setting accept_ra to 2.
59	setAcceptRA("2");
60
61	libh_ = dlopen(if_cmd_lib_file_name, RTLD_NOW | RTLD_LOCAL);
62	if (libh_ == NULL) {
63		const char *err_str = dlerror();
64		ALOGW("Warning (%s) while opening the net interface command library", err_str ? err_str : "unknown");
65	} else {
66		sendCommandInit_ = (int (*)(void))dlsym(libh_, set_cmd_init_func_name);
67		if (sendCommandInit_ == NULL) {
68			const char *err_str = dlerror();
69			ALOGW("Error (%s) while searching for the interface command init function", err_str ? err_str : "unknown");
70		} else if (sendCommandInit_()) {
71			ALOGE("Can't init the interface command API");
72			return;
73		}
74		sendCommandFini_ = (int (*)(void))dlsym(libh_, set_cmd_fini_func_name);
75		if (sendCommandFini_ == NULL) {
76			const char *err_str = dlerror();
77			ALOGW("Error (%s) while searching for the interface command fini function", err_str ? err_str : "unknown");
78		}
79		sendCommand_ = (int (*)(int, char **, char **))dlsym(libh_, set_cmd_func_name);
80		if (sendCommand_ == NULL) {
81			const char *err_str = dlerror();
82			ALOGE("Error (%s) while searching for the interface command function", err_str ? err_str : "unknown");
83			return;
84		}
85	}
86
87	setAcceptRARouteTable(-RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX);
88}
89
90InterfaceController::~InterfaceController() {
91	if (sendCommandFini_) {
92		if (sendCommandFini_()) {
93			ALOGE("Can't shutdown the interface command API");
94		}
95	}
96	if (libh_) {
97		int err = dlclose(libh_);
98		if (err) {
99			const char *err_str = dlerror();
100			ALOGE("Error (%s) while closing the net interface command library", err_str ? err_str : "unknown");
101		}
102	}
103}
104
105/*
106 * Arguments:
107 *	  argv[2] - wlan interface
108 *	  argv[3] - command
109 *	  argv[4] - argument
110 *	  rbuf	- returned buffer
111 */
112int InterfaceController::interfaceCommand(int argc, char *argv[], char **rbuf) {
113	int ret = -ENOSYS;
114	if (!isIfaceName(argv[2])) return -ENOENT;
115	if (sendCommand_)
116		ret = sendCommand_(argc, argv, rbuf);
117
118	return ret;
119}
120
121int InterfaceController::writeIPv6ProcPath(const char *interface, const char *setting, const char *value) {
122	char *path;
123	if (!isIfaceName(interface)) {
124		errno = ENOENT;
125		return -1;
126	}
127	asprintf(&path, "%s/%s/%s", ipv6_proc_path, interface, setting);
128	int success = writeFile(path, value, strlen(value));
129	free(path);
130	return success;
131}
132
133int InterfaceController::setEnableIPv6(const char *interface, const int on) {
134	// When disable_ipv6 changes from 1 to 0, the kernel starts autoconf.
135	// When disable_ipv6 changes from 0 to 1, the kernel clears all autoconf
136	// addresses and routes and disables IPv6 on the interface.
137	const char *disable_ipv6 = on ? "0" : "1";
138	return writeIPv6ProcPath(interface, "disable_ipv6", disable_ipv6);
139}
140
141int InterfaceController::setIPv6PrivacyExtensions(const char *interface, const int on) {
142	// 0: disable IPv6 privacy addresses
143	// 0: enable IPv6 privacy addresses and prefer them over non-privacy ones.
144	return writeIPv6ProcPath(interface, "use_tempaddr", on ? "2" : "0");
145}
146
147int InterfaceController::isInterfaceName(const char *name) {
148	return strcmp(name, ".") &&
149		strcmp(name, "..") &&
150		strcmp(name, "default") &&
151		strcmp(name, "all");
152}
153
154void InterfaceController::setOnAllInterfaces(const char* filename, const char* value) {
155	// Set the default value, which is used by any interfaces that are created in the future.
156	writeIPv6ProcPath("default", filename, value);
157
158	// Set the value on all the interfaces that currently exist.
159	DIR* dir = opendir(ipv6_proc_path);
160	if (!dir) {
161		ALOGE("Can't list %s: %s", ipv6_proc_path, strerror(errno));
162		return;
163	}
164	dirent* d;
165	while ((d = readdir(dir))) {
166		if (d->d_type == DT_DIR && isInterfaceName(d->d_name)) {
167			writeIPv6ProcPath(d->d_name, filename, value);
168		}
169	}
170	closedir(dir);
171}
172
173void InterfaceController::setAcceptRA(const char *value) {
174	setOnAllInterfaces("accept_ra", value);
175}
176
177// |tableOrOffset| is interpreted as:
178//     If == 0: default. Routes go into RT6_TABLE_MAIN.
179//     If > 0: user set. Routes go into the specified table.
180//     If < 0: automatic. The absolute value is intepreted as an offset and added to the interface
181//             ID to get the table. If it's set to -1000, routes from interface ID 5 will go into
182//             table 1005, etc.
183void InterfaceController::setAcceptRARouteTable(int tableOrOffset) {
184	char* value;
185	asprintf(&value, "%d", tableOrOffset);
186	setOnAllInterfaces("accept_ra_rt_table", value);
187	free(value);
188}
189
190int InterfaceController::getMtu(const char *interface, int *mtu)
191{
192	char buf[16];
193	int size = sizeof(buf);
194	char *path;
195	if (!isIfaceName(interface)) {
196		errno = ENOENT;
197		return -1;
198	}
199	asprintf(&path, "%s/%s/mtu", sys_net_path, interface);
200	int success = readFile(path, buf, &size);
201	if (!success && mtu)
202		*mtu = atoi(buf);
203	free(path);
204	return success;
205}
206
207int InterfaceController::setMtu(const char *interface, const char *mtu)
208{
209	char *path;
210	if (!isIfaceName(interface)) {
211		errno = ENOENT;
212		return -1;
213	}
214	asprintf(&path, "%s/%s/mtu", sys_net_path, interface);
215	int success = writeFile(path, mtu, strlen(mtu));
216	free(path);
217	return success;
218}
219