| /* |
| * 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 "NetworkController.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 | O_CLOEXEC); |
| 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::setAcceptIPv6Dad(interface, 0) == 0) |
| && (InterfaceController::setIPv6DadTransmits(interface, "0") == 0) |
| && (InterfaceController::setEnableIPv6(interface, 1) == 0); |
| } |
| |
| void configureForIPv6Client(const char *interface) { |
| InterfaceController::setAcceptIPv6Ra(interface, 1); |
| InterfaceController::setAcceptIPv6Dad(interface, 1); |
| InterfaceController::setIPv6DadTransmits(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 |
| |
| namespace android { |
| namespace net { |
| |
| 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 10 |
| |
| 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]); |
| } |
| |
| Fwmark fwmark; |
| fwmark.netId = NetworkController::LOCAL_NET_ID; |
| fwmark.explicitlySelected = true; |
| fwmark.protectedFromVpn = true; |
| fwmark.permission = PERMISSION_SYSTEM; |
| char markStr[UINT32_HEX_STRLEN]; |
| snprintf(markStr, sizeof(markStr), "0x%x", fwmark.intValue); |
| |
| 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 *)"--listen-mark"; |
| args[8] = (char *)markStr; |
| args[9] = (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; |
| } |
| |
| } // namespace net |
| } // namespace android |