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 LOGD("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 LOGE("Failed to open ip_forward (%s)", strerror(errno)); 68 return -1; 69 } 70 71 if (write(fd, (enable ? "1" : "0"), 1) != 1) { 72 LOGE("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 LOGE("Failed to open ip_forward (%s)", strerror(errno)); 85 return false; 86 } 87 88 char enabled; 89 if (read(fd, &enabled, 1) != 1) { 90 LOGE("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 LOGE("Tethering already started"); 102 errno = EBUSY; 103 return -1; 104 } 105 106 LOGD("Starting tethering services"); 107 108 pid_t pid; 109 int pipefd[2]; 110 111 if (pipe(pipefd) < 0) { 112 LOGE("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 LOGE("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 LOGE("dup2 failed (%s)", strerror(errno)); 132 return -1; 133 } 134 close(pipefd[0]); 135 } 136 137 int num_processed_args = 4 + (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"; 144 145 int nextArg = 4; 146 for (int addrIndex=0; addrIndex < num_addrs;) { 147 char *start = strdup(inet_ntoa(addrs[addrIndex++])); 148 char *end = strdup(inet_ntoa(addrs[addrIndex++])); 149 asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h", start, end); 150 } 151 152 if (execv(args[0], args)) { 153 LOGE("execl failed (%s)", strerror(errno)); 154 } 155 LOGE("Should never get here!"); 156 free(args); 157 return 0; 158 } else { 159 close(pipefd[0]); 160 mDaemonPid = pid; 161 mDaemonFd = pipefd[1]; 162 LOGD("Tethering services running"); 163 } 164 165 return 0; 166 } 167 168 int TetherController::stopTethering() { 169 170 if (mDaemonPid == 0) { 171 LOGE("Tethering already stopped"); 172 return 0; 173 } 174 175 LOGD("Stopping tethering services"); 176 177 kill(mDaemonPid, SIGTERM); 178 waitpid(mDaemonPid, NULL, 0); 179 mDaemonPid = 0; 180 close(mDaemonFd); 181 mDaemonFd = -1; 182 LOGD("Tethering services stopped"); 183 return 0; 184 } 185 186 bool TetherController::isTetheringStarted() { 187 return (mDaemonPid == 0 ? false : true); 188 } 189 190 #define MAX_CMD_SIZE 1024 191 192 int TetherController::setDnsForwarders(char **servers, int numServers) { 193 int i; 194 char daemonCmd[MAX_CMD_SIZE]; 195 196 strcpy(daemonCmd, "update_dns"); 197 int cmdLen = strlen(daemonCmd); 198 199 mDnsForwarders->clear(); 200 for (i = 0; i < numServers; i++) { 201 LOGD("setDnsForwarders(%d = '%s')", i, servers[i]); 202 203 struct in_addr a; 204 205 if (!inet_aton(servers[i], &a)) { 206 LOGE("Failed to parse DNS server '%s'", servers[i]); 207 mDnsForwarders->clear(); 208 return -1; 209 } 210 211 cmdLen += strlen(servers[i]); 212 if (cmdLen + 2 >= MAX_CMD_SIZE) { 213 LOGD("Too many DNS servers listed"); 214 break; 215 } 216 217 strcat(daemonCmd, ":"); 218 strcat(daemonCmd, servers[i]); 219 mDnsForwarders->push_back(a); 220 } 221 222 if (mDaemonFd != -1) { 223 LOGD("Sending update msg to dnsmasq [%s]", daemonCmd); 224 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) { 225 LOGE("Failed to send update command to dnsmasq (%s)", strerror(errno)); 226 mDnsForwarders->clear(); 227 return -1; 228 } 229 } 230 return 0; 231 } 232 233 NetAddressCollection *TetherController::getDnsForwarders() { 234 return mDnsForwarders; 235 } 236 237 int TetherController::tetherInterface(const char *interface) { 238 mInterfaces->push_back(strdup(interface)); 239 return 0; 240 } 241 242 int TetherController::untetherInterface(const char *interface) { 243 InterfaceCollection::iterator it; 244 245 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) { 246 if (!strcmp(interface, *it)) { 247 free(*it); 248 mInterfaces->erase(it); 249 return 0; 250 } 251 } 252 errno = ENOENT; 253 return -1; 254 } 255 256 InterfaceCollection *TetherController::getTetheredInterfaceList() { 257 return mInterfaces; 258 } 259
