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 21 #include <sys/socket.h> 22 #include <sys/stat.h> 23 #include <sys/types.h> 24 #include <sys/wait.h> 25 26 #include <netinet/in.h> 27 #include <arpa/inet.h> 28 29 #define LOG_TAG "TetherController" 30 #include <cutils/log.h> 31 32 33 #include "TetherController.h" 34 35 TetherController::TetherController() { 36 mInterfaces = new InterfaceCollection(); 37 mDnsForwarders = new NetAddressCollection(); 38 mDaemonFd = -1; 39 mDaemonPid = 0; 40 } 41 42 TetherController::~TetherController() { 43 InterfaceCollection::iterator it; 44 45 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) { 46 free(*it); 47 } 48 mInterfaces->clear(); 49 50 mDnsForwarders->clear(); 51 } 52 53 int TetherController::setIpFwdEnabled(bool enable) { 54 55 LOGD("Setting IP forward enable = %d", enable); 56 int fd = open("/proc/sys/net/ipv4/ip_forward", O_WRONLY); 57 if (fd < 0) { 58 LOGE("Failed to open ip_forward (%s)", strerror(errno)); 59 return -1; 60 } 61 62 if (write(fd, (enable ? "1" : "0"), 1) != 1) { 63 LOGE("Failed to write ip_forward (%s)", strerror(errno)); 64 close(fd); 65 return -1; 66 } 67 close(fd); 68 return 0; 69 } 70 71 bool TetherController::getIpFwdEnabled() { 72 int fd = open("/proc/sys/net/ipv4/ip_forward", O_RDONLY); 73 74 if (fd < 0) { 75 LOGE("Failed to open ip_forward (%s)", strerror(errno)); 76 return false; 77 } 78 79 char enabled; 80 if (read(fd, &enabled, 1) != 1) { 81 LOGE("Failed to read ip_forward (%s)", strerror(errno)); 82 close(fd); 83 return -1; 84 } 85 86 close(fd); 87 return (enabled == '1' ? true : false); 88 } 89 90 int TetherController::startTethering(int num_addrs, struct in_addr* addrs) { 91 if (mDaemonPid != 0) { 92 LOGE("Tethering already started"); 93 errno = EBUSY; 94 return -1; 95 } 96 97 LOGD("Starting tethering services"); 98 99 pid_t pid; 100 int pipefd[2]; 101 102 if (pipe(pipefd) < 0) { 103 LOGE("pipe failed (%s)", strerror(errno)); 104 return -1; 105 } 106 107 /* 108 * TODO: Create a monitoring thread to handle and restart 109 * the daemon if it exits prematurely 110 */ 111 if ((pid = fork()) < 0) { 112 LOGE("fork failed (%s)", strerror(errno)); 113 close(pipefd[0]); 114 close(pipefd[1]); 115 return -1; 116 } 117 118 if (!pid) { 119 close(pipefd[1]); 120 if (pipefd[0] != STDIN_FILENO) { 121 if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) { 122 LOGE("dup2 failed (%s)", strerror(errno)); 123 return -1; 124 } 125 close(pipefd[0]); 126 } 127 128 int num_processed_args = 4 + (num_addrs/2) + 1; // 1 null for termination 129 char **args = (char **)malloc(sizeof(char *) * num_processed_args); 130 args[num_processed_args - 1] = NULL; 131 args[0] = (char *)"/system/bin/dnsmasq"; 132 args[1] = (char *)"--no-daemon"; 133 args[2] = (char *)"--no-resolv"; 134 args[3] = (char *)"--no-poll"; 135 136 int nextArg = 4; 137 for (int addrIndex=0; addrIndex < num_addrs;) { 138 char *start = strdup(inet_ntoa(addrs[addrIndex++])); 139 char *end = strdup(inet_ntoa(addrs[addrIndex++])); 140 asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h", start, end); 141 } 142 143 if (execv(args[0], args)) { 144 LOGE("execl failed (%s)", strerror(errno)); 145 } 146 LOGE("Should never get here!"); 147 free(args); 148 return 0; 149 } else { 150 close(pipefd[0]); 151 mDaemonPid = pid; 152 mDaemonFd = pipefd[1]; 153 LOGD("Tethering services running"); 154 } 155 156 return 0; 157 } 158 159 int TetherController::stopTethering() { 160 161 if (mDaemonPid == 0) { 162 LOGE("Tethering already stopped"); 163 return 0; 164 } 165 166 LOGD("Stopping tethering services"); 167 168 kill(mDaemonPid, SIGTERM); 169 waitpid(mDaemonPid, NULL, 0); 170 mDaemonPid = 0; 171 close(mDaemonFd); 172 mDaemonFd = -1; 173 LOGD("Tethering services stopped"); 174 return 0; 175 } 176 177 bool TetherController::isTetheringStarted() { 178 return (mDaemonPid == 0 ? false : true); 179 } 180 181 #define MAX_CMD_SIZE 1024 182 183 int TetherController::setDnsForwarders(char **servers, int numServers) { 184 int i; 185 char daemonCmd[MAX_CMD_SIZE]; 186 187 strcpy(daemonCmd, "update_dns"); 188 int cmdLen = strlen(daemonCmd); 189 190 mDnsForwarders->clear(); 191 for (i = 0; i < numServers; i++) { 192 LOGD("setDnsForwarders(%d = '%s')", i, servers[i]); 193 194 struct in_addr a; 195 196 if (!inet_aton(servers[i], &a)) { 197 LOGE("Failed to parse DNS server '%s'", servers[i]); 198 mDnsForwarders->clear(); 199 return -1; 200 } 201 202 cmdLen += strlen(servers[i]); 203 if (cmdLen + 2 >= MAX_CMD_SIZE) { 204 LOGD("Too many DNS servers listed"); 205 break; 206 } 207 208 strcat(daemonCmd, ":"); 209 strcat(daemonCmd, servers[i]); 210 mDnsForwarders->push_back(a); 211 } 212 213 if (mDaemonFd != -1) { 214 LOGD("Sending update msg to dnsmasq [%s]", daemonCmd); 215 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) { 216 LOGE("Failed to send update command to dnsmasq (%s)", strerror(errno)); 217 mDnsForwarders->clear(); 218 return -1; 219 } 220 } 221 return 0; 222 } 223 224 NetAddressCollection *TetherController::getDnsForwarders() { 225 return mDnsForwarders; 226 } 227 228 int TetherController::tetherInterface(const char *interface) { 229 mInterfaces->push_back(strdup(interface)); 230 return 0; 231 } 232 233 int TetherController::untetherInterface(const char *interface) { 234 InterfaceCollection::iterator it; 235 236 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) { 237 if (!strcmp(interface, *it)) { 238 free(*it); 239 mInterfaces->erase(it); 240 return 0; 241 } 242 } 243 errno = ENOENT; 244 return -1; 245 } 246 247 InterfaceCollection *TetherController::getTetheredInterfaceList() { 248 return mInterfaces; 249 } 250
