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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <dirent.h>
#include <errno.h>
#include <malloc.h>
#define LOG_TAG "InterfaceController"
#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <cutils/log.h>
#include <logwrap/logwrap.h>
#include <netutils/ifc.h>
#include "InterfaceController.h"
#include "RouteController.h"
using android::base::StringPrintf;
using android::base::WriteStringToFile;
namespace {
const char ipv6_proc_path[] = "/proc/sys/net/ipv6/conf";
const char ipv4_neigh_conf_dir[] = "/proc/sys/net/ipv4/neigh";
const char ipv6_neigh_conf_dir[] = "/proc/sys/net/ipv6/neigh";
const char sys_net_path[] = "/sys/class/net";
const char wl_util_path[] = "/vendor/xbin/wlutil";
bool isInterfaceName(const char *name) {
return strcmp(name, ".") &&
strcmp(name, "..") &&
strcmp(name, "default") &&
strcmp(name, "all");
}
int writeValueToPath(
const char* dirname, const char* subdirname, const char* basename,
const char* value) {
std::string path(StringPrintf("%s/%s/%s", dirname, subdirname, basename));
return WriteStringToFile(value, path) ? 0 : -1;
}
void setOnAllInterfaces(const char* dirname, const char* basename, const char* value) {
// Set the default value, which is used by any interfaces that are created in the future.
writeValueToPath(dirname, "default", basename, value);
// Set the value on all the interfaces that currently exist.
DIR* dir = opendir(dirname);
if (!dir) {
ALOGE("Can't list %s: %s", dirname, strerror(errno));
return;
}
dirent* d;
while ((d = readdir(dir))) {
if ((d->d_type != DT_DIR) || !isInterfaceName(d->d_name)) {
continue;
}
writeValueToPath(dirname, d->d_name, basename, value);
}
closedir(dir);
}
void setIPv6UseOutgoingInterfaceAddrsOnly(const char *value) {
setOnAllInterfaces(ipv6_proc_path, "use_oif_addrs_only", value);
}
} // namespace
void InterfaceController::initializeAll() {
// Initial IPv6 settings.
// By default, accept_ra is set to 1 (accept RAs unless forwarding is on) on all interfaces.
// This causes RAs to work or not work based on whether forwarding is on, and causes routes
// learned from RAs to go away when forwarding is turned on. Make this behaviour predictable
// by always setting accept_ra to 2.
setAcceptRA("2");
setAcceptRARouteTable(-RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX);
// Enable optimistic DAD for IPv6 addresses on all interfaces.
setIPv6OptimisticMode("1");
// Reduce the ARP/ND base reachable time from the default (30sec) to 15sec.
setBaseReachableTimeMs(15 * 1000);
// When sending traffic via a given interface use only addresses configured
// on that interface as possible source addresses.
setIPv6UseOutgoingInterfaceAddrsOnly("1");
}
int InterfaceController::setEnableIPv6(const char *interface, const int on) {
if (!isIfaceName(interface)) {
errno = ENOENT;
return -1;
}
// When disable_ipv6 changes from 1 to 0, the kernel starts autoconf.
// When disable_ipv6 changes from 0 to 1, the kernel clears all autoconf
// addresses and routes and disables IPv6 on the interface.
const char *disable_ipv6 = on ? "0" : "1";
return writeValueToPath(ipv6_proc_path, interface, "disable_ipv6", disable_ipv6);
}
int InterfaceController::setAcceptIPv6Ra(const char *interface, const int on) {
if (!isIfaceName(interface)) {
errno = ENOENT;
return -1;
}
// Because forwarding can be enabled even when tethering is off, we always
// use mode "2" (accept RAs, even if forwarding is enabled).
const char *accept_ra = on ? "2" : "0";
return writeValueToPath(ipv6_proc_path, interface, "accept_ra", accept_ra);
}
int InterfaceController::setAcceptIPv6Dad(const char *interface, const int on) {
if (!isIfaceName(interface)) {
errno = ENOENT;
return -1;
}
const char *accept_dad = on ? "1" : "0";
return writeValueToPath(ipv6_proc_path, interface, "accept_dad", accept_dad);
}
int InterfaceController::setIPv6DadTransmits(const char *interface, const char *value) {
if (!isIfaceName(interface)) {
errno = ENOENT;
return -1;
}
return writeValueToPath(ipv6_proc_path, interface, "dad_transmits", value);
}
int InterfaceController::setIPv6PrivacyExtensions(const char *interface, const int on) {
if (!isIfaceName(interface)) {
errno = ENOENT;
return -1;
}
// 0: disable IPv6 privacy addresses
// 0: enable IPv6 privacy addresses and prefer them over non-privacy ones.
return writeValueToPath(ipv6_proc_path, interface, "use_tempaddr", on ? "2" : "0");
}
// Enables or disables IPv6 ND offload. This is useful for 464xlat on wifi, IPv6 tethering, and
// generally implementing IPv6 neighbour discovery and duplicate address detection properly.
// TODO: This should be implemented in wpa_supplicant via driver commands instead.
int InterfaceController::setIPv6NdOffload(char* interface, const int on) {
// Only supported on Broadcom chipsets via wlutil for now.
if (access(wl_util_path, X_OK) == 0) {
const char *argv[] = {
wl_util_path,
"-a",
interface,
"ndoe",
on ? "1" : "0"
};
int ret = android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL,
false, false);
ALOGD("%s ND offload on %s: %d (%s)",
(on ? "enabling" : "disabling"), interface, ret, strerror(errno));
return ret;
} else {
return 0;
}
}
void InterfaceController::setAcceptRA(const char *value) {
setOnAllInterfaces(ipv6_proc_path, "accept_ra", value);
}
// |tableOrOffset| is interpreted as:
// If == 0: default. Routes go into RT6_TABLE_MAIN.
// If > 0: user set. Routes go into the specified table.
// If < 0: automatic. The absolute value is intepreted as an offset and added to the interface
// ID to get the table. If it's set to -1000, routes from interface ID 5 will go into
// table 1005, etc.
void InterfaceController::setAcceptRARouteTable(int tableOrOffset) {
std::string value(StringPrintf("%d", tableOrOffset));
setOnAllInterfaces(ipv6_proc_path, "accept_ra_rt_table", value.c_str());
}
int InterfaceController::setMtu(const char *interface, const char *mtu)
{
if (!isIfaceName(interface)) {
errno = ENOENT;
return -1;
}
return writeValueToPath(sys_net_path, interface, "mtu", mtu);
}
int InterfaceController::addAddress(const char *interface,
const char *addrString, int prefixLength) {
return ifc_add_address(interface, addrString, prefixLength);
}
int InterfaceController::delAddress(const char *interface,
const char *addrString, int prefixLength) {
return ifc_del_address(interface, addrString, prefixLength);
}
void InterfaceController::setBaseReachableTimeMs(unsigned int millis) {
std::string value(StringPrintf("%u", millis));
setOnAllInterfaces(ipv4_neigh_conf_dir, "base_reachable_time_ms", value.c_str());
setOnAllInterfaces(ipv6_neigh_conf_dir, "base_reachable_time_ms", value.c_str());
}
void InterfaceController::setIPv6OptimisticMode(const char *value) {
setOnAllInterfaces(ipv6_proc_path, "optimistic_dad", value);
setOnAllInterfaces(ipv6_proc_path, "use_optimistic", value);
}