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
42char if_cmd_lib_file_name[] = "/system/lib/libnetcmdiface.so";
43char set_cmd_func_name[] = "net_iface_send_command";
44char set_cmd_init_func_name[] = "net_iface_send_command_init";
45char set_cmd_fini_func_name[] = "net_iface_send_command_fini";
46
47const char ipv6_proc_path[] = "/proc/sys/net/ipv6/conf";
48
49const char sys_net_path[] = "/sys/class/net";
50
51InterfaceController::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
87InterfaceController::~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 */
109int 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
117int 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
125int 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
133int 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
139int InterfaceController::isInterfaceName(const char *name) {
140	return strcmp(name, ".") &&
141		strcmp(name, "..") &&
142		strcmp(name, "default") &&
143		strcmp(name, "all");
144}
145
146int 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
169int 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
183int 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