blob: 971104f1add1ccf63bc4aa8d32f6bbd212c3a2cc [file] [log] [blame]
/*
* Copyright (C) 2008 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 <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define LOG_TAG "TetherController"
#include <cutils/log.h>
#include <cutils/properties.h>
#include "Fwmark.h"
#include "NetdConstants.h"
#include "Permission.h"
#include "InterfaceController.h"
#include "TetherController.h"
namespace {
const char BP_TOOLS_MODE[] = "bp-tools";
const char IPV4_FORWARDING_PROC_FILE[] = "/proc/sys/net/ipv4/ip_forward";
const char IPV6_FORWARDING_PROC_FILE[] = "/proc/sys/net/ipv6/conf/all/forwarding";
const char SEPARATOR[] = "|";
bool writeToFile(const char* filename, const char* value) {
int fd = open(filename, O_WRONLY);
if (fd < 0) {
ALOGE("Failed to open %s: %s", filename, strerror(errno));
return false;
}
const ssize_t len = strlen(value);
if (write(fd, value, len) != len) {
ALOGE("Failed to write %s to %s: %s", value, filename, strerror(errno));
close(fd);
return false;
}
close(fd);
return true;
}
bool configureForIPv6Router(const char *interface) {
return (InterfaceController::setEnableIPv6(interface, 0) == 0)
&& (InterfaceController::setAcceptIPv6Ra(interface, 0) == 0)
&& (InterfaceController::setEnableIPv6(interface, 1) == 0);
}
void configureForIPv6Client(const char *interface) {
InterfaceController::setAcceptIPv6Ra(interface, 1);
InterfaceController::setEnableIPv6(interface, 0);
}
bool inBpToolsMode() {
// In BP tools mode, do not disable IP forwarding
char bootmode[PROPERTY_VALUE_MAX] = {0};
property_get("ro.bootmode", bootmode, "unknown");
return !strcmp(BP_TOOLS_MODE, bootmode);
}
} // namespace
TetherController::TetherController() {
mDnsNetId = 0;
mDaemonFd = -1;
mDaemonPid = 0;
if (inBpToolsMode()) {
enableForwarding(BP_TOOLS_MODE);
} else {
setIpFwdEnabled();
}
}
TetherController::~TetherController() {
mInterfaces.clear();
mDnsForwarders.clear();
mForwardingRequests.clear();
}
bool TetherController::setIpFwdEnabled() {
bool success = true;
const char* value = mForwardingRequests.empty() ? "0" : "1";
ALOGD("Setting IP forward enable = %s", value);
success &= writeToFile(IPV4_FORWARDING_PROC_FILE, value);
success &= writeToFile(IPV6_FORWARDING_PROC_FILE, value);
return success;
}
bool TetherController::enableForwarding(const char* requester) {
// Don't return an error if this requester already requested forwarding. Only return errors for
// things that the caller caller needs to care about, such as "couldn't write to the file to
// enable forwarding".
mForwardingRequests.insert(requester);
return setIpFwdEnabled();
}
bool TetherController::disableForwarding(const char* requester) {
mForwardingRequests.erase(requester);
return setIpFwdEnabled();
}
size_t TetherController::forwardingRequestCount() {
return mForwardingRequests.size();
}
#define TETHER_START_CONST_ARG 8
int TetherController::startTethering(int num_addrs, char **dhcp_ranges) {
if (mDaemonPid != 0) {
ALOGE("Tethering already started");
errno = EBUSY;
return -1;
}
ALOGD("Starting tethering services");
pid_t pid;
int pipefd[2];
if (pipe(pipefd) < 0) {
ALOGE("pipe failed (%s)", strerror(errno));
return -1;
}
/*
* TODO: Create a monitoring thread to handle and restart
* the daemon if it exits prematurely
*/
if ((pid = fork()) < 0) {
ALOGE("fork failed (%s)", strerror(errno));
close(pipefd[0]);
close(pipefd[1]);
return -1;
}
if (!pid) {
close(pipefd[1]);
if (pipefd[0] != STDIN_FILENO) {
if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
ALOGE("dup2 failed (%s)", strerror(errno));
return -1;
}
close(pipefd[0]);
}
int num_processed_args = TETHER_START_CONST_ARG + (num_addrs/2) + 1;
char **args = (char **)malloc(sizeof(char *) * num_processed_args);
args[num_processed_args - 1] = NULL;
args[0] = (char *)"/system/bin/dnsmasq";
args[1] = (char *)"--keep-in-foreground";
args[2] = (char *)"--no-resolv";
args[3] = (char *)"--no-poll";
args[4] = (char *)"--dhcp-authoritative";
// TODO: pipe through metered status from ConnService
args[5] = (char *)"--dhcp-option-force=43,ANDROID_METERED";
args[6] = (char *)"--pid-file";
args[7] = (char *)"";
int nextArg = TETHER_START_CONST_ARG;
for (int addrIndex = 0; addrIndex < num_addrs; addrIndex += 2) {
asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h",
dhcp_ranges[addrIndex], dhcp_ranges[addrIndex+1]);
}
if (execv(args[0], args)) {
ALOGE("execl failed (%s)", strerror(errno));
}
ALOGE("Should never get here!");
_exit(-1);
} else {
close(pipefd[0]);
mDaemonPid = pid;
mDaemonFd = pipefd[1];
applyDnsInterfaces();
ALOGD("Tethering services running");
}
return 0;
}
int TetherController::stopTethering() {
if (mDaemonPid == 0) {
ALOGE("Tethering already stopped");
return 0;
}
ALOGD("Stopping tethering services");
kill(mDaemonPid, SIGTERM);
waitpid(mDaemonPid, NULL, 0);
mDaemonPid = 0;
close(mDaemonFd);
mDaemonFd = -1;
ALOGD("Tethering services stopped");
return 0;
}
bool TetherController::isTetheringStarted() {
return (mDaemonPid == 0 ? false : true);
}
#define MAX_CMD_SIZE 1024
int TetherController::setDnsForwarders(unsigned netId, char **servers, int numServers) {
int i;
char daemonCmd[MAX_CMD_SIZE];
Fwmark fwmark;
fwmark.netId = netId;
fwmark.explicitlySelected = true;
fwmark.protectedFromVpn = true;
fwmark.permission = PERMISSION_SYSTEM;
snprintf(daemonCmd, sizeof(daemonCmd), "update_dns%s0x%x", SEPARATOR, fwmark.intValue);
int cmdLen = strlen(daemonCmd);
mDnsForwarders.clear();
for (i = 0; i < numServers; i++) {
ALOGD("setDnsForwarders(0x%x %d = '%s')", fwmark.intValue, i, servers[i]);
addrinfo *res, hints = { .ai_flags = AI_NUMERICHOST };
int ret = getaddrinfo(servers[i], NULL, &hints, &res);
freeaddrinfo(res);
if (ret) {
ALOGE("Failed to parse DNS server '%s'", servers[i]);
mDnsForwarders.clear();
errno = EINVAL;
return -1;
}
cmdLen += (strlen(servers[i]) + 1);
if (cmdLen + 1 >= MAX_CMD_SIZE) {
ALOGD("Too many DNS servers listed");
break;
}
strcat(daemonCmd, SEPARATOR);
strcat(daemonCmd, servers[i]);
mDnsForwarders.push_back(servers[i]);
}
mDnsNetId = netId;
if (mDaemonFd != -1) {
ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
mDnsForwarders.clear();
errno = EREMOTEIO;
return -1;
}
}
return 0;
}
unsigned TetherController::getDnsNetId() {
return mDnsNetId;
}
const std::list<std::string> &TetherController::getDnsForwarders() const {
return mDnsForwarders;
}
bool TetherController::applyDnsInterfaces() {
char daemonCmd[MAX_CMD_SIZE];
strcpy(daemonCmd, "update_ifaces");
int cmdLen = strlen(daemonCmd);
bool haveInterfaces = false;
for (const auto &ifname : mInterfaces) {
cmdLen += (ifname.size() + 1);
if (cmdLen + 1 >= MAX_CMD_SIZE) {
ALOGD("Too many DNS ifaces listed");
break;
}
strcat(daemonCmd, SEPARATOR);
strcat(daemonCmd, ifname.c_str());
haveInterfaces = true;
}
if ((mDaemonFd != -1) && haveInterfaces) {
ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
return false;
}
}
return true;
}
int TetherController::tetherInterface(const char *interface) {
ALOGD("tetherInterface(%s)", interface);
if (!isIfaceName(interface)) {
errno = ENOENT;
return -1;
}
if (!configureForIPv6Router(interface)) {
configureForIPv6Client(interface);
return -1;
}
mInterfaces.push_back(interface);
if (!applyDnsInterfaces()) {
mInterfaces.pop_back();
configureForIPv6Client(interface);
return -1;
} else {
return 0;
}
}
int TetherController::untetherInterface(const char *interface) {
ALOGD("untetherInterface(%s)", interface);
for (auto it = mInterfaces.cbegin(); it != mInterfaces.cend(); ++it) {
if (!strcmp(interface, it->c_str())) {
mInterfaces.erase(it);
configureForIPv6Client(interface);
return applyDnsInterfaces() ? 0 : -1;
}
}
errno = ENOENT;
return -1;
}
const std::list<std::string> &TetherController::getTetheredInterfaceList() const {
return mInterfaces;
}