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 #include <errno.h>
19 #include <malloc.h>
20
21 #define LOG_TAG "InterfaceController"
22 #include <android-base/file.h>
23 #include <android-base/stringprintf.h>
24 #include <cutils/log.h>
25 #include <logwrap/logwrap.h>
26
27 #include "InterfaceController.h"
28 #include "RouteController.h"
29
30 using android::base::StringPrintf;
31 using android::base::WriteStringToFile;
32
33 namespace {
34
35 const char ipv6_proc_path[] = "/proc/sys/net/ipv6/conf";
36
37 const char ipv4_neigh_conf_dir[] = "/proc/sys/net/ipv4/neigh";
38
39 const char ipv6_neigh_conf_dir[] = "/proc/sys/net/ipv6/neigh";
40
41 const char sys_net_path[] = "/sys/class/net";
42
43 const char wl_util_path[] = "/vendor/xbin/wlutil";
44
isInterfaceName(const char * name)45 bool isInterfaceName(const char *name) {
46 return strcmp(name, ".") &&
47 strcmp(name, "..") &&
48 strcmp(name, "default") &&
49 strcmp(name, "all");
50 }
51
writeValueToPath(const char * dirname,const char * subdirname,const char * basename,const char * value)52 int writeValueToPath(
53 const char* dirname, const char* subdirname, const char* basename,
54 const char* value) {
55 std::string path(StringPrintf("%s/%s/%s", dirname, subdirname, basename));
56 return WriteStringToFile(value, path) ? 0 : -1;
57 }
58
setOnAllInterfaces(const char * dirname,const char * basename,const char * value)59 void setOnAllInterfaces(const char* dirname, const char* basename, const char* value) {
60 // Set the default value, which is used by any interfaces that are created in the future.
61 writeValueToPath(dirname, "default", basename, value);
62
63 // Set the value on all the interfaces that currently exist.
64 DIR* dir = opendir(dirname);
65 if (!dir) {
66 ALOGE("Can't list %s: %s", dirname, strerror(errno));
67 return;
68 }
69 dirent* d;
70 while ((d = readdir(dir))) {
71 if ((d->d_type != DT_DIR) || !isInterfaceName(d->d_name)) {
72 continue;
73 }
74 writeValueToPath(dirname, d->d_name, basename, value);
75 }
76 closedir(dir);
77 }
78
setIPv6UseOutgoingInterfaceAddrsOnly(const char * value)79 void setIPv6UseOutgoingInterfaceAddrsOnly(const char *value) {
80 setOnAllInterfaces(ipv6_proc_path, "use_oif_addrs_only", value);
81 }
82
83 } // namespace
84
InterfaceController()85 InterfaceController::InterfaceController() {
86 // Initial IPv6 settings.
87 // By default, accept_ra is set to 1 (accept RAs unless forwarding is on) on all interfaces.
88 // This causes RAs to work or not work based on whether forwarding is on, and causes routes
89 // learned from RAs to go away when forwarding is turned on. Make this behaviour predictable
90 // by always setting accept_ra to 2.
91 setAcceptRA("2");
92
93 setAcceptRARouteTable(-RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX);
94
95 // Enable optimistic DAD for IPv6 addresses on all interfaces.
96 setIPv6OptimisticMode("1");
97
98 // Reduce the ARP/ND base reachable time from the default (30sec) to 15sec.
99 setBaseReachableTimeMs(15 * 1000);
100
101 // When sending traffic via a given interface use only addresses configured
102 // on that interface as possible source addresses.
103 setIPv6UseOutgoingInterfaceAddrsOnly("1");
104 }
105
~InterfaceController()106 InterfaceController::~InterfaceController() {
107 }
108
setEnableIPv6(const char * interface,const int on)109 int InterfaceController::setEnableIPv6(const char *interface, const int on) {
110 if (!isIfaceName(interface)) {
111 errno = ENOENT;
112 return -1;
113 }
114 // When disable_ipv6 changes from 1 to 0, the kernel starts autoconf.
115 // When disable_ipv6 changes from 0 to 1, the kernel clears all autoconf
116 // addresses and routes and disables IPv6 on the interface.
117 const char *disable_ipv6 = on ? "0" : "1";
118 return writeValueToPath(ipv6_proc_path, interface, "disable_ipv6", disable_ipv6);
119 }
120
setIPv6PrivacyExtensions(const char * interface,const int on)121 int InterfaceController::setIPv6PrivacyExtensions(const char *interface, const int on) {
122 if (!isIfaceName(interface)) {
123 errno = ENOENT;
124 return -1;
125 }
126 // 0: disable IPv6 privacy addresses
127 // 0: enable IPv6 privacy addresses and prefer them over non-privacy ones.
128 return writeValueToPath(ipv6_proc_path, interface, "use_tempaddr", on ? "2" : "0");
129 }
130
131 // Enables or disables IPv6 ND offload. This is useful for 464xlat on wifi, IPv6 tethering, and
132 // generally implementing IPv6 neighbour discovery and duplicate address detection properly.
133 // TODO: This should be implemented in wpa_supplicant via driver commands instead.
setIPv6NdOffload(char * interface,const int on)134 int InterfaceController::setIPv6NdOffload(char* interface, const int on) {
135 // Only supported on Broadcom chipsets via wlutil for now.
136 if (access(wl_util_path, X_OK) == 0) {
137 const char *argv[] = {
138 wl_util_path,
139 "-a",
140 interface,
141 "ndoe",
142 on ? "1" : "0"
143 };
144 int ret = android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL,
145 false, false);
146 ALOGD("%s ND offload on %s: %d (%s)",
147 (on ? "enabling" : "disabling"), interface, ret, strerror(errno));
148 return ret;
149 } else {
150 return 0;
151 }
152 }
153
setAcceptRA(const char * value)154 void InterfaceController::setAcceptRA(const char *value) {
155 setOnAllInterfaces(ipv6_proc_path, "accept_ra", value);
156 }
157
158 // |tableOrOffset| is interpreted as:
159 // If == 0: default. Routes go into RT6_TABLE_MAIN.
160 // If > 0: user set. Routes go into the specified table.
161 // If < 0: automatic. The absolute value is intepreted as an offset and added to the interface
162 // ID to get the table. If it's set to -1000, routes from interface ID 5 will go into
163 // table 1005, etc.
setAcceptRARouteTable(int tableOrOffset)164 void InterfaceController::setAcceptRARouteTable(int tableOrOffset) {
165 std::string value(StringPrintf("%d", tableOrOffset));
166 setOnAllInterfaces(ipv6_proc_path, "accept_ra_rt_table", value.c_str());
167 }
168
setMtu(const char * interface,const char * mtu)169 int InterfaceController::setMtu(const char *interface, const char *mtu)
170 {
171 if (!isIfaceName(interface)) {
172 errno = ENOENT;
173 return -1;
174 }
175 return writeValueToPath(sys_net_path, interface, "mtu", mtu);
176 }
177
setBaseReachableTimeMs(unsigned int millis)178 void InterfaceController::setBaseReachableTimeMs(unsigned int millis) {
179 std::string value(StringPrintf("%u", millis));
180 setOnAllInterfaces(ipv4_neigh_conf_dir, "base_reachable_time_ms", value.c_str());
181 setOnAllInterfaces(ipv6_neigh_conf_dir, "base_reachable_time_ms", value.c_str());
182 }
183
setIPv6OptimisticMode(const char * value)184 void InterfaceController::setIPv6OptimisticMode(const char *value) {
185 setOnAllInterfaces(ipv6_proc_path, "optimistic_dad", value);
186 setOnAllInterfaces(ipv6_proc_path, "use_optimistic", value);
187 }
188