InterfaceController.cpp revision 0ea8ff87012f6bda41b6d2b4629d4fd0fd6f4794 
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 <dirent.h>
18
19#define LOG_TAG "InterfaceController"
20#include <cutils/log.h>
21#include <logwrap/logwrap.h>
22
23#include "InterfaceController.h"
24#include "RouteController.h"
25
26const char ipv6_proc_path[] = "/proc/sys/net/ipv6/conf";
27
28const char sys_net_path[] = "/sys/class/net";
29
30const char wl_util_path[] = "/system/xbin/wlutil";
31
32InterfaceController::InterfaceController() {
33	// Initial IPv6 settings.
34	// By default, accept_ra is set to 1 (accept RAs unless forwarding is on) on all interfaces.
35	// This causes RAs to work or not work based on whether forwarding is on, and causes routes
36	// learned from RAs to go away when forwarding is turned on. Make this behaviour predictable
37	// by always setting accept_ra to 2.
38	setAcceptRA("2");
39
40	setAcceptRARouteTable(-RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX);
41}
42
43InterfaceController::~InterfaceController() {
44}
45
46int InterfaceController::writeIPv6ProcPath(const char *interface, const char *setting, const char *value) {
47	char *path;
48	if (!isIfaceName(interface)) {
49		errno = ENOENT;
50		return -1;
51	}
52	asprintf(&path, "%s/%s/%s", ipv6_proc_path, interface, setting);
53	int success = writeFile(path, value, strlen(value));
54	free(path);
55	return success;
56}
57
58int InterfaceController::setEnableIPv6(const char *interface, const int on) {
59	// When disable_ipv6 changes from 1 to 0, the kernel starts autoconf.
60	// When disable_ipv6 changes from 0 to 1, the kernel clears all autoconf
61	// addresses and routes and disables IPv6 on the interface.
62	const char *disable_ipv6 = on ? "0" : "1";
63	return writeIPv6ProcPath(interface, "disable_ipv6", disable_ipv6);
64}
65
66int InterfaceController::setIPv6PrivacyExtensions(const char *interface, const int on) {
67	// 0: disable IPv6 privacy addresses
68	// 0: enable IPv6 privacy addresses and prefer them over non-privacy ones.
69	return writeIPv6ProcPath(interface, "use_tempaddr", on ? "2" : "0");
70}
71
72// Enables or disables IPv6 ND offload. This is useful for 464xlat on wifi, IPv6 tethering, and
73// generally implementing IPv6 neighbour discovery and duplicate address detection properly.
74// TODO: This should be implemented in wpa_supplicant via driver commands instead.
75int InterfaceController::setIPv6NdOffload(char* interface, const int on) {
76    // Only supported on Broadcom chipsets via wlutil for now.
77    if (access(wl_util_path, X_OK) == 0) {
78        const char *argv[] = {
79            wl_util_path,
80            "-a",
81            interface,
82            "ndoe",
83            on ? "1" : "0"
84        };
85        int ret = android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL,
86                                      false, false);
87        ALOGD("%s ND offload on %s: %d (%s)",
88              (on ? "enabling" : "disabling"), interface, ret, strerror(errno));
89        return ret;
90    } else {
91        return 0;
92    }
93}
94
95int InterfaceController::isInterfaceName(const char *name) {
96	return strcmp(name, ".") &&
97		strcmp(name, "..") &&
98		strcmp(name, "default") &&
99		strcmp(name, "all");
100}
101
102void InterfaceController::setOnAllInterfaces(const char* filename, const char* value) {
103	// Set the default value, which is used by any interfaces that are created in the future.
104	writeIPv6ProcPath("default", filename, value);
105
106	// Set the value on all the interfaces that currently exist.
107	DIR* dir = opendir(ipv6_proc_path);
108	if (!dir) {
109		ALOGE("Can't list %s: %s", ipv6_proc_path, strerror(errno));
110		return;
111	}
112	dirent* d;
113	while ((d = readdir(dir))) {
114		if (d->d_type == DT_DIR && isInterfaceName(d->d_name)) {
115			writeIPv6ProcPath(d->d_name, filename, value);
116		}
117	}
118	closedir(dir);
119}
120
121void InterfaceController::setAcceptRA(const char *value) {
122	setOnAllInterfaces("accept_ra", value);
123}
124
125// |tableOrOffset| is interpreted as:
126//     If == 0: default. Routes go into RT6_TABLE_MAIN.
127//     If > 0: user set. Routes go into the specified table.
128//     If < 0: automatic. The absolute value is intepreted as an offset and added to the interface
129//             ID to get the table. If it's set to -1000, routes from interface ID 5 will go into
130//             table 1005, etc.
131void InterfaceController::setAcceptRARouteTable(int tableOrOffset) {
132	char* value;
133	asprintf(&value, "%d", tableOrOffset);
134	setOnAllInterfaces("accept_ra_rt_table", value);
135	free(value);
136}
137
138int InterfaceController::setMtu(const char *interface, const char *mtu)
139{
140	char *path;
141	if (!isIfaceName(interface)) {
142		errno = ENOENT;
143		return -1;
144	}
145	asprintf(&path, "%s/%s/mtu", sys_net_path, interface);
146	int success = writeFile(path, mtu, strlen(mtu));
147	free(path);
148	return success;
149}
150