1/* 2 * Copyright 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/* Utilities for managing the dhcpcd DHCP client daemon */ 18 19#include <stdio.h> 20#include <stdlib.h> 21#include <string.h> 22#include <unistd.h> 23#include <arpa/inet.h> 24#include <netinet/in.h> 25 26#include <cutils/properties.h> 27 28static const char DAEMON_NAME[] = "dhcpcd"; 29static const char DAEMON_PROP_NAME[] = "init.svc.dhcpcd"; 30static const char HOSTNAME_PROP_NAME[] = "net.hostname"; 31static const char DHCP_PROP_NAME_PREFIX[] = "dhcp"; 32static const char DHCP_CONFIG_PATH[] = "/system/etc/dhcpcd/dhcpcd.conf"; 33static const int NAP_TIME = 200; /* wait for 200ms at a time */ 34 /* when polling for property values */ 35static const char DAEMON_NAME_RENEW[] = "iprenew"; 36static char errmsg[100] = "\0"; 37/* interface length for dhcpcd daemon start (dhcpcd_<interface> as defined in init.rc file) 38 * or for filling up system properties dhcpcd.<interface>.ipaddress, dhcpcd.<interface>.dns1 39 * and other properties on a successful bind 40 */ 41#define MAX_INTERFACE_LENGTH 25 42 43/* 44 * P2p interface names increase sequentially p2p-p2p0-1, p2p-p2p0-2.. after 45 * group formation. This does not work well with system properties which can quickly 46 * exhaust or for specifiying a dhcp start target in init which requires 47 * interface to be pre-defined in init.rc file. 48 * 49 * This function returns a common string p2p for all p2p interfaces. 50 */ 51void get_p2p_interface_replacement(const char *interface, char *p2p_interface) { 52 /* Use p2p for any interface starting with p2p. */ 53 if (strncmp(interface, "p2p",3) == 0) { 54 strncpy(p2p_interface, "p2p", MAX_INTERFACE_LENGTH); 55 } else { 56 strncpy(p2p_interface, interface, MAX_INTERFACE_LENGTH); 57 } 58} 59 60/* 61 * Wait for a system property to be assigned a specified value. 62 * If desired_value is NULL, then just wait for the property to 63 * be created with any value. maxwait is the maximum amount of 64 * time in seconds to wait before giving up. 65 */ 66static int wait_for_property(const char *name, const char *desired_value, int maxwait) 67{ 68 char value[PROPERTY_VALUE_MAX] = {'\0'}; 69 int maxnaps = (maxwait * 1000) / NAP_TIME; 70 71 if (maxnaps < 1) { 72 maxnaps = 1; 73 } 74 75 while (maxnaps-- >= 0) { 76 if (property_get(name, value, NULL)) { 77 if (desired_value == NULL || 78 strcmp(value, desired_value) == 0) { 79 return 0; 80 } 81 } 82 if (maxnaps >= 0) { 83 usleep(NAP_TIME * 1000); 84 } 85 } 86 return -1; /* failure */ 87} 88 89static int fill_ip_info(const char *interface, 90 char *ipaddr, 91 char *gateway, 92 uint32_t *prefixLength, 93 char *dns[], 94 char *server, 95 uint32_t *lease, 96 char *vendorInfo, 97 char *domain, 98 char *mtu) 99{ 100 char prop_name[PROPERTY_KEY_MAX]; 101 char prop_value[PROPERTY_VALUE_MAX]; 102 /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */ 103 char p2p_interface[MAX_INTERFACE_LENGTH]; 104 int x; 105 106 get_p2p_interface_replacement(interface, p2p_interface); 107 108 snprintf(prop_name, sizeof(prop_name), "%s.%s.ipaddress", DHCP_PROP_NAME_PREFIX, p2p_interface); 109 property_get(prop_name, ipaddr, NULL); 110 111 snprintf(prop_name, sizeof(prop_name), "%s.%s.gateway", DHCP_PROP_NAME_PREFIX, p2p_interface); 112 property_get(prop_name, gateway, NULL); 113 114 snprintf(prop_name, sizeof(prop_name), "%s.%s.server", DHCP_PROP_NAME_PREFIX, p2p_interface); 115 property_get(prop_name, server, NULL); 116 117 //TODO: Handle IPv6 when we change system property usage 118 if (gateway[0] == '\0' || strncmp(gateway, "0.0.0.0", 7) == 0) { 119 //DHCP server is our best bet as gateway 120 strncpy(gateway, server, PROPERTY_VALUE_MAX); 121 } 122 123 snprintf(prop_name, sizeof(prop_name), "%s.%s.mask", DHCP_PROP_NAME_PREFIX, p2p_interface); 124 if (property_get(prop_name, prop_value, NULL)) { 125 int p; 126 // this conversion is v4 only, but this dhcp client is v4 only anyway 127 in_addr_t mask = ntohl(inet_addr(prop_value)); 128 // Check netmask is a valid IP address. ntohl gives NONE response (all 1's) for 129 // non 255.255.255.255 inputs. if we get that value check if it is legit.. 130 if (mask == INADDR_NONE && strcmp(prop_value, "255.255.255.255") != 0) { 131 snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value); 132 return -1; 133 } 134 for (p = 0; p < 32; p++) { 135 if (mask == 0) break; 136 // check for non-contiguous netmask, e.g., 255.254.255.0 137 if ((mask & 0x80000000) == 0) { 138 snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value); 139 return -1; 140 } 141 mask = mask << 1; 142 } 143 *prefixLength = p; 144 } 145 146 for (x=0; dns[x] != NULL; x++) { 147 snprintf(prop_name, sizeof(prop_name), "%s.%s.dns%d", DHCP_PROP_NAME_PREFIX, p2p_interface, x+1); 148 property_get(prop_name, dns[x], NULL); 149 } 150 151 snprintf(prop_name, sizeof(prop_name), "%s.%s.leasetime", DHCP_PROP_NAME_PREFIX, p2p_interface); 152 if (property_get(prop_name, prop_value, NULL)) { 153 *lease = atol(prop_value); 154 } 155 156 snprintf(prop_name, sizeof(prop_name), "%s.%s.vendorInfo", DHCP_PROP_NAME_PREFIX, 157 p2p_interface); 158 property_get(prop_name, vendorInfo, NULL); 159 160 snprintf(prop_name, sizeof(prop_name), "%s.%s.domain", DHCP_PROP_NAME_PREFIX, 161 p2p_interface); 162 property_get(prop_name, domain, NULL); 163 164 snprintf(prop_name, sizeof(prop_name), "%s.%s.mtu", DHCP_PROP_NAME_PREFIX, 165 p2p_interface); 166 property_get(prop_name, mtu, NULL); 167 168 return 0; 169} 170 171/* 172 * Get any available DHCP results. 173 */ 174int dhcp_get_results(const char *interface, 175 char *ipaddr, 176 char *gateway, 177 uint32_t *prefixLength, 178 char *dns[], 179 char *server, 180 uint32_t *lease, 181 char *vendorInfo, 182 char *domain, 183 char *mtu) 184{ 185 char result_prop_name[PROPERTY_KEY_MAX]; 186 char prop_value[PROPERTY_VALUE_MAX]; 187 188 /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */ 189 char p2p_interface[MAX_INTERFACE_LENGTH]; 190 get_p2p_interface_replacement(interface, p2p_interface); 191 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result", 192 DHCP_PROP_NAME_PREFIX, 193 p2p_interface); 194 195 memset(prop_value, '\0', PROPERTY_VALUE_MAX); 196 if (!property_get(result_prop_name, prop_value, NULL)) { 197 snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set"); 198 return -1; 199 } 200 if (strcmp(prop_value, "ok") == 0) { 201 if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns, 202 server, lease, vendorInfo, domain, mtu) == -1) { 203 return -1; 204 } 205 return 0; 206 } else { 207 snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value); 208 return -1; 209 } 210} 211 212/* 213 * Start the dhcp client daemon, and wait for it to finish 214 * configuring the interface. 215 * 216 * The device init.rc file needs a corresponding entry for this work. 217 * 218 * Example: 219 * service dhcpcd_<interface> /system/bin/dhcpcd -ABKL -f dhcpcd.conf 220 */ 221int dhcp_start(const char *interface) 222{ 223 char result_prop_name[PROPERTY_KEY_MAX]; 224 char daemon_prop_name[PROPERTY_KEY_MAX]; 225 char prop_value[PROPERTY_VALUE_MAX] = {'\0'}; 226 char daemon_cmd[PROPERTY_VALUE_MAX * 2 + sizeof(DHCP_CONFIG_PATH)]; 227 const char *ctrl_prop = "ctl.start"; 228 const char *desired_status = "running"; 229 /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */ 230 char p2p_interface[MAX_INTERFACE_LENGTH]; 231 232 get_p2p_interface_replacement(interface, p2p_interface); 233 234 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result", 235 DHCP_PROP_NAME_PREFIX, 236 p2p_interface); 237 238 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s", 239 DAEMON_PROP_NAME, 240 p2p_interface); 241 242 /* Erase any previous setting of the dhcp result property */ 243 property_set(result_prop_name, ""); 244 245 /* Start the daemon and wait until it's ready */ 246 if (property_get(HOSTNAME_PROP_NAME, prop_value, NULL) && (prop_value[0] != '\0')) 247 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s -h %s %s", DAEMON_NAME, 248 p2p_interface, DHCP_CONFIG_PATH, prop_value, interface); 249 else 250 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s %s", DAEMON_NAME, 251 p2p_interface, DHCP_CONFIG_PATH, interface); 252 memset(prop_value, '\0', PROPERTY_VALUE_MAX); 253 property_set(ctrl_prop, daemon_cmd); 254 if (wait_for_property(daemon_prop_name, desired_status, 10) < 0) { 255 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for dhcpcd to start"); 256 return -1; 257 } 258 259 /* Wait for the daemon to return a result */ 260 if (wait_for_property(result_prop_name, NULL, 30) < 0) { 261 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP to finish"); 262 return -1; 263 } 264 265 return 0; 266} 267 268/** 269 * Stop the DHCP client daemon. 270 */ 271int dhcp_stop(const char *interface) 272{ 273 char result_prop_name[PROPERTY_KEY_MAX]; 274 char daemon_prop_name[PROPERTY_KEY_MAX]; 275 char daemon_cmd[PROPERTY_VALUE_MAX * 2]; 276 const char *ctrl_prop = "ctl.stop"; 277 const char *desired_status = "stopped"; 278 279 char p2p_interface[MAX_INTERFACE_LENGTH]; 280 281 get_p2p_interface_replacement(interface, p2p_interface); 282 283 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result", 284 DHCP_PROP_NAME_PREFIX, 285 p2p_interface); 286 287 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s", 288 DAEMON_PROP_NAME, 289 p2p_interface); 290 291 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface); 292 293 /* Stop the daemon and wait until it's reported to be stopped */ 294 property_set(ctrl_prop, daemon_cmd); 295 if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) { 296 return -1; 297 } 298 property_set(result_prop_name, "failed"); 299 return 0; 300} 301 302/** 303 * Release the current DHCP client lease. 304 */ 305int dhcp_release_lease(const char *interface) 306{ 307 char daemon_prop_name[PROPERTY_KEY_MAX]; 308 char daemon_cmd[PROPERTY_VALUE_MAX * 2]; 309 const char *ctrl_prop = "ctl.stop"; 310 const char *desired_status = "stopped"; 311 312 char p2p_interface[MAX_INTERFACE_LENGTH]; 313 314 get_p2p_interface_replacement(interface, p2p_interface); 315 316 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s", 317 DAEMON_PROP_NAME, 318 p2p_interface); 319 320 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface); 321 322 /* Stop the daemon and wait until it's reported to be stopped */ 323 property_set(ctrl_prop, daemon_cmd); 324 if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) { 325 return -1; 326 } 327 return 0; 328} 329 330char *dhcp_get_errmsg() { 331 return errmsg; 332} 333 334/** 335 * The device init.rc file needs a corresponding entry. 336 * 337 * Example: 338 * service iprenew_<interface> /system/bin/dhcpcd -n 339 * 340 */ 341int dhcp_start_renew(const char *interface) 342{ 343 char result_prop_name[PROPERTY_KEY_MAX]; 344 char prop_value[PROPERTY_VALUE_MAX] = {'\0'}; 345 char daemon_cmd[PROPERTY_VALUE_MAX * 2]; 346 const char *ctrl_prop = "ctl.start"; 347 348 char p2p_interface[MAX_INTERFACE_LENGTH]; 349 350 get_p2p_interface_replacement(interface, p2p_interface); 351 352 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result", 353 DHCP_PROP_NAME_PREFIX, 354 p2p_interface); 355 356 /* Erase any previous setting of the dhcp result property */ 357 property_set(result_prop_name, ""); 358 359 /* Start the renew daemon and wait until it's ready */ 360 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:%s", DAEMON_NAME_RENEW, 361 p2p_interface, interface); 362 memset(prop_value, '\0', PROPERTY_VALUE_MAX); 363 property_set(ctrl_prop, daemon_cmd); 364 365 /* Wait for the daemon to return a result */ 366 if (wait_for_property(result_prop_name, NULL, 30) < 0) { 367 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP Renew to finish"); 368 return -1; 369 } 370 371 return 0; 372} 373