1 /* 2 * Copyright (C) 2008 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 <stdlib.h> 18 #include <errno.h> 19 #include <fcntl.h> 20 #include <string.h> 21 22 #include <sys/socket.h> 23 #include <sys/stat.h> 24 #include <sys/types.h> 25 #include <sys/wait.h> 26 27 #include <netinet/in.h> 28 #include <arpa/inet.h> 29 30 #define LOG_TAG "TetherController" 31 #include <cutils/log.h> 32 #include <cutils/properties.h> 33 34 #include "TetherController.h" 35 36 TetherController::TetherController() { 37 mInterfaces = new InterfaceCollection(); 38 mDnsForwarders = new NetAddressCollection(); 39 mDaemonFd = -1; 40 mDaemonPid = 0; 41 } 42 43 TetherController::~TetherController() { 44 InterfaceCollection::iterator it; 45 46 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) { 47 free(*it); 48 } 49 mInterfaces->clear(); 50 51 mDnsForwarders->clear(); 52 } 53 54 int TetherController::setIpFwdEnabled(bool enable) { 55 56 ALOGD("Setting IP forward enable = %d", enable); 57 58 // In BP tools mode, do not disable IP forwarding 59 char bootmode[PROPERTY_VALUE_MAX] = {0}; 60 property_get("ro.bootmode", bootmode, "unknown"); 61 if ((enable == false) && (0 == strcmp("bp-tools", bootmode))) { 62 return 0; 63 } 64 65 int fd = open("/proc/sys/net/ipv4/ip_forward", O_WRONLY); 66 if (fd < 0) { 67 ALOGE("Failed to open ip_forward (%s)", strerror(errno)); 68 return -1; 69 } 70 71 if (write(fd, (enable ? "1" : "0"), 1) != 1) { 72 ALOGE("Failed to write ip_forward (%s)", strerror(errno)); 73 close(fd); 74 return -1; 75 } 76 close(fd); 77 return 0; 78 } 79 80 bool TetherController::getIpFwdEnabled() { 81 int fd = open("/proc/sys/net/ipv4/ip_forward", O_RDONLY); 82 83 if (fd < 0) { 84 ALOGE("Failed to open ip_forward (%s)", strerror(errno)); 85 return false; 86 } 87 88 char enabled; 89 if (read(fd, &enabled, 1) != 1) { 90 ALOGE("Failed to read ip_forward (%s)", strerror(errno)); 91 close(fd); 92 return -1; 93 } 94 95 close(fd); 96 return (enabled == '1' ? true : false); 97 } 98 99 int TetherController::startTethering(int num_addrs, struct in_addr* addrs) { 100 if (mDaemonPid != 0) { 101 ALOGE("Tethering already started"); 102 errno = EBUSY; 103 return -1; 104 } 105 106 ALOGD("Starting tethering services"); 107 108 pid_t pid; 109 int pipefd[2]; 110 111 if (pipe(pipefd) < 0) { 112 ALOGE("pipe failed (%s)", strerror(errno)); 113 return -1; 114 } 115 116 /* 117 * TODO: Create a monitoring thread to handle and restart 118 * the daemon if it exits prematurely 119 */ 120 if ((pid = fork()) < 0) { 121 ALOGE("fork failed (%s)", strerror(errno)); 122 close(pipefd[0]); 123 close(pipefd[1]); 124 return -1; 125 } 126 127 if (!pid) { 128 close(pipefd[1]); 129 if (pipefd[0] != STDIN_FILENO) { 130 if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) { 131 ALOGE("dup2 failed (%s)", strerror(errno)); 132 return -1; 133 } 134 close(pipefd[0]); 135 } 136 137 int num_processed_args = 5 + (num_addrs/2) + 1; // 1 null for termination 138 char **args = (char **)malloc(sizeof(char *) * num_processed_args); 139 args[num_processed_args - 1] = NULL; 140 args[0] = (char *)"/system/bin/dnsmasq"; 141 args[1] = (char *)"--no-daemon"; 142 args[2] = (char *)"--no-resolv"; 143 args[3] = (char *)"--no-poll"; 144 // TODO: pipe through metered status from ConnService 145 args[4] = (char *)"--dhcp-option-force=43,ANDROID_METERED"; 146 147 int nextArg = 5; 148 for (int addrIndex=0; addrIndex < num_addrs;) { 149 char *start = strdup(inet_ntoa(addrs[addrIndex++])); 150 char *end = strdup(inet_ntoa(addrs[addrIndex++])); 151 asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h", start, end); 152 } 153 154 if (execv(args[0], args)) { 155 ALOGE("execl failed (%s)", strerror(errno)); 156 } 157 ALOGE("Should never get here!"); 158 free(args); 159 return 0; 160 } else { 161 close(pipefd[0]); 162 mDaemonPid = pid; 163 mDaemonFd = pipefd[1]; 164 ALOGD("Tethering services running"); 165 } 166 167 return 0; 168 } 169 170 int TetherController::stopTethering() { 171 172 if (mDaemonPid == 0) { 173 ALOGE("Tethering already stopped"); 174 return 0; 175 } 176 177 ALOGD("Stopping tethering services"); 178 179 kill(mDaemonPid, SIGTERM); 180 waitpid(mDaemonPid, NULL, 0); 181 mDaemonPid = 0; 182 close(mDaemonFd); 183 mDaemonFd = -1; 184 ALOGD("Tethering services stopped"); 185 return 0; 186 } 187 188 bool TetherController::isTetheringStarted() { 189 return (mDaemonPid == 0 ? false : true); 190 } 191 192 #define MAX_CMD_SIZE 1024 193 194 int TetherController::setDnsForwarders(char **servers, int numServers) { 195 int i; 196 char daemonCmd[MAX_CMD_SIZE]; 197 198 strcpy(daemonCmd, "update_dns"); 199 int cmdLen = strlen(daemonCmd); 200 201 mDnsForwarders->clear(); 202 for (i = 0; i < numServers; i++) { 203 ALOGD("setDnsForwarders(%d = '%s')", i, servers[i]); 204 205 struct in_addr a; 206 207 if (!inet_aton(servers[i], &a)) { 208 ALOGE("Failed to parse DNS server '%s'", servers[i]); 209 mDnsForwarders->clear(); 210 return -1; 211 } 212 213 cmdLen += strlen(servers[i]); 214 if (cmdLen + 2 >= MAX_CMD_SIZE) { 215 ALOGD("Too many DNS servers listed"); 216 break; 217 } 218 219 strcat(daemonCmd, ":"); 220 strcat(daemonCmd, servers[i]); 221 mDnsForwarders->push_back(a); 222 } 223 224 if (mDaemonFd != -1) { 225 ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd); 226 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) { 227 ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno)); 228 mDnsForwarders->clear(); 229 return -1; 230 } 231 } 232 return 0; 233 } 234 235 NetAddressCollection *TetherController::getDnsForwarders() { 236 return mDnsForwarders; 237 } 238 239 int TetherController::tetherInterface(const char *interface) { 240 mInterfaces->push_back(strdup(interface)); 241 return 0; 242 } 243 244 int TetherController::untetherInterface(const char *interface) { 245 InterfaceCollection::iterator it; 246 247 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) { 248 if (!strcmp(interface, *it)) { 249 free(*it); 250 mInterfaces->erase(it); 251 return 0; 252 } 253 } 254 errno = ENOENT; 255 return -1; 256 } 257 258 InterfaceCollection *TetherController::getTetheredInterfaceList() { 259 return mInterfaces; 260 } 261
