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 <unistd.h> 22 #include <arpa/inet.h> 23 #include <netinet/in.h> 24 25 #include <cutils/properties.h> 26 27 static const char DAEMON_NAME[] = "dhcpcd"; 28 static const char DAEMON_PROP_NAME[] = "init.svc.dhcpcd"; 29 static const char HOSTNAME_PROP_NAME[] = "net.hostname"; 30 static const char DHCP_PROP_NAME_PREFIX[] = "dhcp"; 31 static const int NAP_TIME = 1; /* wait for 1 second at a time */ 32 /* when polling for property values */ 33 static char errmsg[100]; 34 35 /* 36 * Wait for a system property to be assigned a specified value. 37 * If desired_value is NULL, then just wait for the property to 38 * be created with any value. maxwait is the maximum amount of 39 * time in seconds to wait before giving up. 40 */ 41 static int wait_for_property(const char *name, const char *desired_value, int maxwait) 42 { 43 char value[PROPERTY_VALUE_MAX] = {'\0'}; 44 int maxnaps = maxwait / NAP_TIME; 45 46 if (maxnaps < 1) { 47 maxnaps = 1; 48 } 49 50 while (maxnaps-- > 0) { 51 usleep(1000000); 52 if (property_get(name, value, NULL)) { 53 if (desired_value == NULL || 54 strcmp(value, desired_value) == 0) { 55 return 0; 56 } 57 } 58 } 59 return -1; /* failure */ 60 } 61 62 static void fill_ip_info(const char *interface, 63 in_addr_t *ipaddr, 64 in_addr_t *gateway, 65 in_addr_t *mask, 66 in_addr_t *dns1, 67 in_addr_t *dns2, 68 in_addr_t *server, 69 uint32_t *lease) 70 { 71 char prop_name[PROPERTY_KEY_MAX]; 72 char prop_value[PROPERTY_VALUE_MAX]; 73 struct in_addr addr; 74 in_addr_t iaddr; 75 76 snprintf(prop_name, sizeof(prop_name), "%s.%s.ipaddress", DHCP_PROP_NAME_PREFIX, interface); 77 if (property_get(prop_name, prop_value, NULL) && inet_aton(prop_value, &addr)) { 78 *ipaddr = addr.s_addr; 79 } else { 80 *ipaddr = 0; 81 } 82 snprintf(prop_name, sizeof(prop_name), "%s.%s.gateway", DHCP_PROP_NAME_PREFIX, interface); 83 if (property_get(prop_name, prop_value, NULL) && inet_aton(prop_value, &addr)) { 84 *gateway = addr.s_addr; 85 } else { 86 *gateway = 0; 87 } 88 snprintf(prop_name, sizeof(prop_name), "%s.%s.mask", DHCP_PROP_NAME_PREFIX, interface); 89 if (property_get(prop_name, prop_value, NULL) && inet_aton(prop_value, &addr)) { 90 *mask = addr.s_addr; 91 } else { 92 *mask = 0; 93 } 94 snprintf(prop_name, sizeof(prop_name), "%s.%s.dns1", DHCP_PROP_NAME_PREFIX, interface); 95 if (property_get(prop_name, prop_value, NULL) && inet_aton(prop_value, &addr)) { 96 *dns1 = addr.s_addr; 97 } else { 98 *dns1 = 0; 99 } 100 snprintf(prop_name, sizeof(prop_name), "%s.%s.dns2", DHCP_PROP_NAME_PREFIX, interface); 101 if (property_get(prop_name, prop_value, NULL) && inet_aton(prop_value, &addr)) { 102 *dns2 = addr.s_addr; 103 } else { 104 *dns2 = 0; 105 } 106 snprintf(prop_name, sizeof(prop_name), "%s.%s.server", DHCP_PROP_NAME_PREFIX, interface); 107 if (property_get(prop_name, prop_value, NULL) && inet_aton(prop_value, &addr)) { 108 *server = addr.s_addr; 109 } else { 110 *server = 0; 111 } 112 snprintf(prop_name, sizeof(prop_name), "%s.%s.leasetime", DHCP_PROP_NAME_PREFIX, interface); 113 if (property_get(prop_name, prop_value, NULL)) { 114 *lease = atol(prop_value); 115 } 116 } 117 118 /* 119 * Start the dhcp client daemon, and wait for it to finish 120 * configuring the interface. 121 */ 122 int dhcp_do_request(const char *interface, 123 in_addr_t *ipaddr, 124 in_addr_t *gateway, 125 in_addr_t *mask, 126 in_addr_t *dns1, 127 in_addr_t *dns2, 128 in_addr_t *server, 129 uint32_t *lease) 130 { 131 char result_prop_name[PROPERTY_KEY_MAX]; 132 char prop_value[PROPERTY_VALUE_MAX] = {'\0'}; 133 char daemon_cmd[PROPERTY_VALUE_MAX * 2]; 134 const char *ctrl_prop = "ctl.start"; 135 const char *desired_status = "running"; 136 137 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result", 138 DHCP_PROP_NAME_PREFIX, 139 interface); 140 /* Erase any previous setting of the dhcp result property */ 141 property_set(result_prop_name, ""); 142 143 /* Start the daemon and wait until it's ready */ 144 if (property_get(HOSTNAME_PROP_NAME, prop_value, NULL) && (prop_value[0] != '\0')) 145 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s:-h %s %s", DAEMON_NAME, 146 prop_value, interface); 147 else 148 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s:%s", DAEMON_NAME, interface); 149 memset(prop_value, '\0', PROPERTY_VALUE_MAX); 150 property_set(ctrl_prop, daemon_cmd); 151 if (wait_for_property(DAEMON_PROP_NAME, desired_status, 10) < 0) { 152 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for dhcpcd to start"); 153 return -1; 154 } 155 156 /* Wait for the daemon to return a result */ 157 if (wait_for_property(result_prop_name, NULL, 30) < 0) { 158 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP to finish"); 159 return -1; 160 } 161 162 if (!property_get(result_prop_name, prop_value, NULL)) { 163 /* shouldn't ever happen, given the success of wait_for_property() */ 164 snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set"); 165 return -1; 166 } 167 if (strcmp(prop_value, "ok") == 0) { 168 fill_ip_info(interface, ipaddr, gateway, mask, dns1, dns2, server, lease); 169 return 0; 170 } else { 171 snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value); 172 return -1; 173 } 174 } 175 176 /** 177 * Stop the DHCP client daemon. 178 */ 179 int dhcp_stop(const char *interface) 180 { 181 char result_prop_name[PROPERTY_KEY_MAX]; 182 const char *ctrl_prop = "ctl.stop"; 183 const char *desired_status = "stopped"; 184 185 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result", 186 DHCP_PROP_NAME_PREFIX, 187 interface); 188 /* Stop the daemon and wait until it's reported to be stopped */ 189 property_set(ctrl_prop, DAEMON_NAME); 190 if (wait_for_property(DAEMON_PROP_NAME, desired_status, 5) < 0) { 191 return -1; 192 } 193 property_set(result_prop_name, "failed"); 194 return 0; 195 } 196 197 /** 198 * Release the current DHCP client lease. 199 */ 200 int dhcp_release_lease(const char *interface) 201 { 202 const char *ctrl_prop = "ctl.stop"; 203 const char *desired_status = "stopped"; 204 205 /* Stop the daemon and wait until it's reported to be stopped */ 206 property_set(ctrl_prop, DAEMON_NAME); 207 if (wait_for_property(DAEMON_PROP_NAME, desired_status, 5) < 0) { 208 return -1; 209 } 210 return 0; 211 } 212 213 char *dhcp_get_errmsg() { 214 return errmsg; 215 } 216
