1 /* 2 * Copyright 2011 Daniel Drown 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 * config.c - configuration settings 17 */ 18 19 #include <string.h> 20 #include <stdlib.h> 21 #include <arpa/inet.h> 22 #include <stdio.h> 23 #include <limits.h> 24 #include <errno.h> 25 #include <unistd.h> 26 27 #include <cutils/config_utils.h> 28 29 #include "config.h" 30 #include "dns64.h" 31 #include "logging.h" 32 #include "getaddr.h" 33 #include "clatd.h" 34 #include "setroute.h" 35 36 struct clat_config Global_Clatd_Config; 37 38 /* function: config_item_str 39 * locates the config item and returns the pointer to a string, or NULL on failure. Caller frees pointer 40 * root - parsed configuration 41 * item_name - name of config item to locate 42 * defaultvar - value to use if config item isn't present 43 */ 44 char *config_item_str(cnode *root, const char *item_name, const char *defaultvar) { 45 const char *tmp; 46 47 if(!(tmp = config_str(root, item_name, defaultvar))) { 48 logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name); 49 return NULL; 50 } 51 return strdup(tmp); 52 } 53 54 /* function: config_item_int16_t 55 * locates the config item, parses the integer, and returns the pointer ret_val_ptr, or NULL on failure 56 * root - parsed configuration 57 * item_name - name of config item to locate 58 * defaultvar - value to use if config item isn't present 59 * ret_val_ptr - pointer for return value storage 60 */ 61 int16_t *config_item_int16_t(cnode *root, const char *item_name, const char *defaultvar, int16_t *ret_val_ptr) { 62 const char *tmp; 63 char *endptr; 64 long int conf_int; 65 66 if(!(tmp = config_str(root, item_name, defaultvar))) { 67 logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name); 68 return NULL; 69 } 70 71 errno = 0; 72 conf_int = strtol(tmp,&endptr,10); 73 if(errno > 0) { 74 logmsg(ANDROID_LOG_FATAL,"%s config item is not numeric: %s (error=%s)",item_name,tmp,strerror(errno)); 75 return NULL; 76 } 77 if(endptr == tmp || *tmp == '\0') { 78 logmsg(ANDROID_LOG_FATAL,"%s config item is not numeric: %s",item_name,tmp); 79 return NULL; 80 } 81 if(*endptr != '\0') { 82 logmsg(ANDROID_LOG_FATAL,"%s config item contains non-numeric characters: %s",item_name,endptr); 83 return NULL; 84 } 85 if(conf_int > INT16_MAX || conf_int < INT16_MIN) { 86 logmsg(ANDROID_LOG_FATAL,"%s config item is too big/small: %d",item_name,conf_int); 87 return NULL; 88 } 89 *ret_val_ptr = conf_int; 90 return ret_val_ptr; 91 } 92 93 /* function: config_item_ip 94 * locates the config item, parses the ipv4 address, and returns the pointer ret_val_ptr, or NULL on failure 95 * root - parsed configuration 96 * item_name - name of config item to locate 97 * defaultvar - value to use if config item isn't present 98 * ret_val_ptr - pointer for return value storage 99 */ 100 struct in_addr *config_item_ip(cnode *root, const char *item_name, const char *defaultvar, struct in_addr *ret_val_ptr) { 101 const char *tmp; 102 int status; 103 104 if(!(tmp = config_str(root, item_name, defaultvar))) { 105 logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name); 106 return NULL; 107 } 108 109 status = inet_pton(AF_INET, tmp, ret_val_ptr); 110 if(status <= 0) { 111 logmsg(ANDROID_LOG_FATAL,"invalid IPv4 address specified for %s: %s", item_name, tmp); 112 return NULL; 113 } 114 115 return ret_val_ptr; 116 } 117 118 /* function: config_item_ip6 119 * locates the config item, parses the ipv6 address, and returns the pointer ret_val_ptr, or NULL on failure 120 * root - parsed configuration 121 * item_name - name of config item to locate 122 * defaultvar - value to use if config item isn't present 123 * ret_val_ptr - pointer for return value storage 124 */ 125 struct in6_addr *config_item_ip6(cnode *root, const char *item_name, const char *defaultvar, struct in6_addr *ret_val_ptr) { 126 const char *tmp; 127 int status; 128 129 if(!(tmp = config_str(root, item_name, defaultvar))) { 130 logmsg(ANDROID_LOG_FATAL,"%s config item needed",item_name); 131 return NULL; 132 } 133 134 status = inet_pton(AF_INET6, tmp, ret_val_ptr); 135 if(status <= 0) { 136 logmsg(ANDROID_LOG_FATAL,"invalid IPv6 address specified for %s: %s", item_name, tmp); 137 return NULL; 138 } 139 140 return ret_val_ptr; 141 } 142 143 /* function: free_config 144 * frees the memory used by the global config variable 145 */ 146 void free_config() { 147 if(Global_Clatd_Config.plat_from_dns64_hostname) { 148 free(Global_Clatd_Config.plat_from_dns64_hostname); 149 Global_Clatd_Config.plat_from_dns64_hostname = NULL; 150 } 151 } 152 153 /* function: dns64_detection 154 * does dns lookups to set the plat subnet or exits on failure, waits forever for a dns response with a query backoff timer 155 */ 156 void dns64_detection() { 157 int i, backoff_sleep, status; 158 struct in6_addr tmp_ptr; 159 160 backoff_sleep = 1; 161 162 while(1) { 163 status = plat_prefix(Global_Clatd_Config.plat_from_dns64_hostname,&tmp_ptr); 164 if(status > 0) { 165 memcpy(&Global_Clatd_Config.plat_subnet, &tmp_ptr, sizeof(struct in6_addr)); 166 return; 167 } 168 if(status < 0) { 169 logmsg(ANDROID_LOG_FATAL, "dns64_detection/no dns64, giving up\n"); 170 exit(1); 171 } 172 logmsg(ANDROID_LOG_WARN, "dns64_detection failed, sleeping for %d seconds", backoff_sleep); 173 sleep(backoff_sleep); 174 if(backoff_sleep >= 120) { 175 backoff_sleep = 120; 176 } else { 177 backoff_sleep *= 2; 178 } 179 } 180 } 181 182 183 /* function: config_generate_local_ipv6_subnet 184 * generates the local ipv6 subnet when given the interface ip 185 * requires config.ipv6_host_id 186 * interface_ip - in: interface ip, out: local ipv6 host address 187 */ 188 void config_generate_local_ipv6_subnet(struct in6_addr *interface_ip) { 189 int i; 190 191 for(i = 2; i < 4; i++) { 192 interface_ip->s6_addr32[i] = Global_Clatd_Config.ipv6_host_id.s6_addr32[i]; 193 } 194 } 195 196 /* function: subnet_from_interface 197 * finds the ipv6 subnet configured on the specified interface 198 * root - parsed configuration 199 * interface - network interface name 200 */ 201 int subnet_from_interface(cnode *root, const char *interface) { 202 union anyip *interface_ip; 203 204 if(!config_item_ip6(root, "ipv6_host_id", "::200:5E10:0:0", &Global_Clatd_Config.ipv6_host_id)) 205 return 0; 206 207 interface_ip = getinterface_ip(interface, AF_INET6); 208 if(!interface_ip) { 209 logmsg(ANDROID_LOG_FATAL,"unable to find an ipv6 ip on interface %s",interface); 210 return 0; 211 } 212 213 memcpy(&Global_Clatd_Config.ipv6_local_subnet, &interface_ip->ip6, sizeof(struct in6_addr)); 214 free(interface_ip); 215 216 config_generate_local_ipv6_subnet(&Global_Clatd_Config.ipv6_local_subnet); 217 218 return 1; 219 } 220 221 /* function: read_config 222 * reads the config file and parses it into the global variable Global_Clatd_Config. returns 0 on failure, 1 on success 223 * file - filename to parse 224 * uplink_interface - interface to use to reach the internet and supplier of address space 225 * plat_prefix - (optional) plat prefix to use, otherwise follow config file 226 */ 227 int read_config(const char *file, const char *uplink_interface, const char *plat_prefix) { 228 cnode *root = config_node("", ""); 229 void *tmp_ptr = NULL; 230 231 if(!root) { 232 logmsg(ANDROID_LOG_FATAL,"out of memory"); 233 return 0; 234 } 235 236 memset(&Global_Clatd_Config, '\0', sizeof(Global_Clatd_Config)); 237 238 config_load_file(root, file); 239 if(root->first_child == NULL) { 240 logmsg(ANDROID_LOG_FATAL,"Could not read config file %s", file); 241 goto failed; 242 } 243 244 strncpy(Global_Clatd_Config.default_pdp_interface, uplink_interface, sizeof(Global_Clatd_Config.default_pdp_interface)); 245 246 if(!subnet_from_interface(root,Global_Clatd_Config.default_pdp_interface)) 247 goto failed; 248 249 if(!config_item_int16_t(root, "mtu", "-1", &Global_Clatd_Config.mtu)) 250 goto failed; 251 252 if(!config_item_int16_t(root, "ipv4mtu", "-1", &Global_Clatd_Config.ipv4mtu)) 253 goto failed; 254 255 if(!config_item_ip(root, "ipv4_local_subnet", DEFAULT_IPV4_LOCAL_SUBNET, &Global_Clatd_Config.ipv4_local_subnet)) 256 goto failed; 257 258 if(plat_prefix) { // plat subnet is coming from the command line 259 if(inet_pton(AF_INET6, plat_prefix, &Global_Clatd_Config.plat_subnet) <= 0) { 260 logmsg(ANDROID_LOG_FATAL,"invalid IPv6 address specified for plat prefix: %s", plat_prefix); 261 goto failed; 262 } 263 } else { 264 tmp_ptr = (void *)config_item_str(root, "plat_from_dns64", "yes"); 265 if(!tmp_ptr || strcmp(tmp_ptr, "no") == 0) { 266 free(tmp_ptr); 267 268 if(!config_item_ip6(root, "plat_subnet", NULL, &Global_Clatd_Config.plat_subnet)) { 269 logmsg(ANDROID_LOG_FATAL, "plat_from_dns64 disabled, but no plat_subnet specified"); 270 goto failed; 271 } 272 } else { 273 free(tmp_ptr); 274 275 if(!(Global_Clatd_Config.plat_from_dns64_hostname = config_item_str(root, "plat_from_dns64_hostname", DEFAULT_DNS64_DETECTION_HOSTNAME))) 276 goto failed; 277 dns64_detection(); 278 } 279 } 280 281 282 return 1; 283 284 failed: 285 free(root); 286 free_config(); 287 return 0; 288 } 289 290 /* function; dump_config 291 * prints the current config 292 */ 293 void dump_config() { 294 char charbuffer[INET6_ADDRSTRLEN]; 295 296 logmsg(ANDROID_LOG_DEBUG,"mtu = %d",Global_Clatd_Config.mtu); 297 logmsg(ANDROID_LOG_DEBUG,"ipv4mtu = %d",Global_Clatd_Config.ipv4mtu); 298 logmsg(ANDROID_LOG_DEBUG,"ipv6_local_subnet = %s",inet_ntop(AF_INET6, &Global_Clatd_Config.ipv6_local_subnet, charbuffer, sizeof(charbuffer))); 299 logmsg(ANDROID_LOG_DEBUG,"ipv4_local_subnet = %s",inet_ntop(AF_INET, &Global_Clatd_Config.ipv4_local_subnet, charbuffer, sizeof(charbuffer))); 300 logmsg(ANDROID_LOG_DEBUG,"plat_subnet = %s",inet_ntop(AF_INET6, &Global_Clatd_Config.plat_subnet, charbuffer, sizeof(charbuffer))); 301 logmsg(ANDROID_LOG_DEBUG,"default_pdp_interface = %s",Global_Clatd_Config.default_pdp_interface); 302 } 303
