dnsinfo/dnsinfo_flatfile.c

   1 /*
   2  * Copyright (c) 2009 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <dirent.h>
  25 #include <fcntl.h>
  26 #include <libgen.h>
  27 #include <netdb.h>
  28 #include <resolv.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <sys/dir.h>
  33 #include <unistd.h>
  34
  35 #include "dnsinfo.h"
  36 #include "dnsinfo_private.h"
  37 #include "dnsinfo_create.h"
  38
  39 enum {
  40         TOKEN_NAMESERVER,
  41         TOKEN_PORT,
  42         TOKEN_DOMAIN,
  43         TOKEN_SEARCH,
  44         TOKEN_SEARCH_ORDER,
  45         TOKEN_SORTLIST,
  46         TOKEN_TIMEOUT,
  47         TOKEN_OPTIONS,
  48         TOKEN_MAX
  49 };
  50
  51 /*
  52  * tokens
  53  * The supported configuration token strings and enumerated values.
  54  */
  55 static const struct {
  56         const char      *name;
  57         int             token;
  58         int             max_count;
  59 } tokens [] = {
  60         { "nameserver",         TOKEN_NAMESERVER,       MAXNS   },
  61         { "port",               TOKEN_PORT,             1       },
  62         { "domain",             TOKEN_DOMAIN,           1       },
  63         { "search",             TOKEN_SEARCH,           1       },
  64         { "search_order",       TOKEN_SEARCH_ORDER,     1       },
  65         { "sortlist",           TOKEN_SORTLIST,         1       },
  66         { "timeout",            TOKEN_TIMEOUT,          1       },
  67         { "options",            TOKEN_OPTIONS,          1       },
  68 };
  69
  70
  71 /*
  72  * _dnsinfo_parse_address
  73  *
  74  * Parse IP address
  75  */
  76 static struct sockaddr *
  77 _dnsinfo_parse_address(char *nameserver)
  78 {
  79         struct addrinfo *ai;
  80         struct addrinfo hints;
  81         int             res;
  82         struct sockaddr *sa     = NULL;
  83
  84         memset(&hints, 0, sizeof(hints));
  85         hints.ai_flags = AI_NUMERICHOST;
  86
  87         res = getaddrinfo(nameserver, NULL, &hints, &ai);
  88         if (res == 0) {
  89                 if ((ai->ai_family == AF_INET) || (ai->ai_family == AF_INET6)) {
  90                         sa = malloc(ai->ai_addrlen);
  91                         memcpy(sa, ai->ai_addr, ai->ai_addrlen);
  92                 }
  93                 freeaddrinfo(ai);
  94         }
  95
  96         return sa;
  97 }
  98
  99
 100 /*
 101  * _dnsinfo_parse_nameserver
 102  *
 103  * Parse arguments to the nameserver token. This is essentially a getaddrinfo(3)
 104  * with AI_NUMERICHOST. However, if the conversion fails, check if the address
 105  * contains an optional trailing '.' followed by a numeric port number.  If found,
 106  * remove the port number and retry the conversion (e.g. 127.0.0.1.55 or ::1.55).
 107  */
 108 static struct sockaddr *
 109 _dnsinfo_parse_nameserver(char *token)
 110 {
 111         char            *dot;
 112         long            number;
 113         struct sockaddr *sa;
 114
 115         sa = _dnsinfo_parse_address(token);
 116         if (sa != NULL) {
 117                 return sa;
 118         }
 119
 120         // if we could not parse address, attempt to remove
 121         // an optional trailing port number
 122         dot = strrchr(token, '.');
 123         if (dot == NULL) {
 124                 return NULL;
 125         }
 126
 127         number = strtol(dot + 1, NULL, 10);
 128         if ((number < 0) || (number > UINT16_MAX)) {
 129                 return NULL;
 130         }
 131
 132         *dot = '\0';
 133         sa = _dnsinfo_parse_address(token);
 134         if (sa != NULL) {
 135                 in_port_t       port    = htons(number);
 136
 137                 switch (sa->sa_family) {
 138                         case AF_INET :
 139                                 ((struct sockaddr_in *)sa)->sin_port = port;
 140                                 break;
 141                         case AF_INET6 :
 142                                 ((struct sockaddr_in6 *)sa)->sin6_port = port;
 143                                 break;
 144                 }
 145         }
 146
 147         return sa;
 148 }
 149
 150
 151 /*
 152  * _dnsinfo_parse_sortaddr
 153  *
 154  * Parse arguments to the sortlist token.
 155  */
 156 static dns_sortaddr_t *
 157 _dnsinfo_parse_sortaddr(char *token)
 158 {
 159         struct in_addr          addr;
 160         struct in_addr          mask;
 161         struct sockaddr         *sa;
 162         char                    *slash;
 163         dns_sortaddr_t          *sortaddr       = NULL;
 164
 165         slash = strchr(token, '/');
 166         if (slash != NULL) {
 167                 *slash = '\0';
 168         }
 169
 170         sa = _dnsinfo_parse_address(token);
 171         if (sa == NULL) {
 172                 // if we could not parse the address
 173                 goto done;
 174         } else if (sa->sa_family != AF_INET) {
 175                 // if not AF_INET
 176                 goto done;
 177         } else {
 178                 addr = ((struct sockaddr_in *)sa)->sin_addr;
 179                 free(sa);
 180                 sa = NULL;
 181         }
 182
 183         if (slash != NULL) {
 184                 sa = _dnsinfo_parse_address(slash + 1);
 185                 if (sa == NULL) {
 186                         // if we could not parse the provided mask
 187                         goto done;
 188                 } else if (sa->sa_family != AF_INET) {
 189                         // if mask not AF_INET
 190                         goto done;
 191                 } else {
 192                         mask = ((struct sockaddr_in *)sa)->sin_addr;
 193                         free(sa);
 194                         sa = NULL;
 195                 }
 196         } else {
 197                 in_addr_t       a;
 198                 in_addr_t       m;
 199
 200                 a = ntohl(addr.s_addr);
 201                 if (IN_CLASSA(a)) {
 202                         m = IN_CLASSA_NET;
 203                 } else if (IN_CLASSB(a)) {
 204                         m = IN_CLASSB_NET;
 205                 } else if (IN_CLASSC(a)) {
 206                         m = IN_CLASSC_NET;
 207                 } else {
 208                         goto done;
 209                 }
 210
 211                 mask.s_addr = htonl(m);
 212         }
 213
 214         sortaddr = malloc(sizeof(*sortaddr));
 215         sortaddr->address = addr;
 216         sortaddr->mask    = mask;
 217
 218     done :
 219
 220         if (sa != NULL) free(sa);
 221         return sortaddr;
 222 }
 223
 224
 225 /*
 226  * _dnsinfo_flatfile_create_resolver
 227  *
 228  * Create a new dns resolver configuration from the configuration file at the
 229  * specified path. (e.g. /etc/resolv.conf or /etc/resolver/apple.com)
 230  */
 231 static dns_create_resolver_t
 232 _dnsinfo_flatfile_create_resolver(const char *dir, const char *path)
 233 {
 234         char                    *buf;
 235         FILE                    *f;
 236         char                    filename[FILENAME_MAX];
 237         size_t                  len                     = 0;
 238         char                    *line                   = NULL;
 239         dns_create_resolver_t   res                     = NULL;
 240         const char              *sep                    = " \t";
 241         int                     token_count[TOKEN_MAX]  = { 0 };
 242
 243         filename[0] = 0;
 244         if (dir != NULL) {
 245                 strlcpy(filename, dir, sizeof(filename));
 246                 strlcat(filename, "/", sizeof(filename));
 247         }
 248         strlcat(filename, path, sizeof(filename));
 249
 250         f = fopen(filename, "r");
 251         if (f == NULL) return NULL;
 252
 253         while ((buf = fgetln(f, &len)) != NULL) {
 254                 int     i;
 255                 char    *lineptr;
 256                 int     max_count;
 257                 int     token;
 258                 char    *word;
 259
 260                 if (len == 0) continue;
 261                 if (buf[len-1] == '\n') buf[len-1] = '\0';
 262
 263                 line = reallocf(line, len+1);
 264                 if (line == NULL) continue;
 265
 266                 strncpy(line, buf, len);
 267                 line[len] = '\0';
 268
 269                 // parse the first word of the line (the config token)
 270                 lineptr = line;
 271                 word = strsep(&lineptr, sep);
 272                 if (word == NULL) {
 273                         // if empty line
 274                         continue;
 275                 }
 276                 if (word[0] == ';' || word[0] == '#') {
 277                         // if comment
 278                         continue;
 279                 }
 280
 281                 // translate config token to enumerated value
 282                 token = -1;
 283                 for (i = 0; i < sizeof(tokens) / sizeof(tokens[0]); i++) {
 284                         if (strcasecmp(word, tokens[i].name) == 0) {
 285                                 token     = tokens[i].token;
 286                                 max_count = tokens[i].max_count;
 287                                 break;
 288                         }
 289                 }
 290                 if (token == -1) {
 291                         // if not a recognized token
 292                         continue;
 293                 }
 294
 295                 // parse the next word of the line (the config option)
 296                 word = strsep(&lineptr, sep);
 297                 if (word == NULL) {
 298                         // if no option
 299                         continue;
 300                 }
 301                 if (++token_count[token] > max_count) {
 302                         // if too many options
 303                         continue;
 304                 }
 305
 306                 // create resolver
 307                 if (res == NULL) {
 308                         res = _dns_resolver_create();
 309                         if (res == NULL) {
 310                                 // if we could not create a resolver
 311                                 goto done;
 312                         }
 313                 }
 314
 315                 switch (token) {
 316                         case TOKEN_DOMAIN:
 317                                 _dns_resolver_set_domain(&res, word);
 318                                 break;
 319
 320                         case TOKEN_NAMESERVER: {
 321                                 struct sockaddr *sa;
 322
 323                                 sa = _dnsinfo_parse_nameserver(word);
 324                                 if (sa != NULL) {
 325                                         _dns_resolver_add_nameserver(&res, sa);
 326                                         free(sa);
 327                                 }
 328                                 break;
 329                         }
 330
 331                         case TOKEN_PORT: {
 332                                 long    number  = -1;
 333
 334                                 number = strtol(word, NULL, 0);
 335                                 if (number < 0 || number > UINT16_MAX) break;
 336                                 _dns_resolver_set_port(&res, number);
 337                                 break;
 338                         }
 339
 340                         case TOKEN_SEARCH: {
 341                                 int     n       = 0;
 342
 343                                 // multiple search domains are supported
 344                                 while ((word != NULL) && (n++ < MAXDNSRCH)) {
 345                                         _dns_resolver_add_search(&res, word);
 346                                         word = strsep(&lineptr, sep);
 347                                 }
 348                                 break;
 349                         }
 350
 351                         case TOKEN_SORTLIST: {
 352                                 int     n       = 0;
 353
 354                                 while ((word != NULL) && (n++ < MAXRESOLVSORT)) {
 355                                         dns_sortaddr_t  *sortaddr;
 356
 357                                         sortaddr = _dnsinfo_parse_sortaddr(word);
 358                                         if (sortaddr == NULL) break;
 359                                         _dns_resolver_add_sortaddr(&res, sortaddr);
 360                                         free(sortaddr);
 361                                         word = strsep(&lineptr, sep);
 362                                 }
 363                                 break;
 364                         }
 365
 366                         case TOKEN_OPTIONS:
 367                                 _dns_resolver_set_options(&res, lineptr);
 368                                 break;
 369
 370                         case TOKEN_TIMEOUT: {
 371                                 long    number  = -1;
 372
 373                                 number = strtol(word, NULL, 0);
 374                                 if (number < 0 || number > UINT32_MAX) break;
 375                                 _dns_resolver_set_timeout(&res, number);
 376                                 break;
 377                         }
 378
 379                         case TOKEN_SEARCH_ORDER: {
 380                                 long    number  = -1;
 381
 382                                 number = strtol(word, NULL, 0);
 383                                 if (number < 0 || number > UINT32_MAX) break;
 384                                 _dns_resolver_set_order(&res, number);
 385                                 break;
 386                         }
 387                 }
 388         }
 389         if (line != NULL) free(line);
 390
 391         // set the domain to the basename of the path if not specified
 392         if ((res != NULL) && (token_count[TOKEN_DOMAIN] == 0)) {
 393                 const char      *domain;
 394
 395                 domain = strrchr(path, '/');
 396                 if (domain == NULL) {
 397                         domain = path;
 398                 } else {
 399                         domain = domain + 1;
 400                 }
 401                 _dns_resolver_set_domain(&res, domain);
 402         }
 403
 404     done :
 405
 406         fclose(f);
 407         return res;
 408 }
 409
 410
 411 /*
 412  * _dnsinfo_flatfile_add_resolvers
 413  *
 414  * Parse the files in the resolver config directory (/etc/resolver) and add each
 415  * resolver to the dns config.
 416  */
 417 void
 418 _dnsinfo_flatfile_add_resolvers(dns_create_config_t *config)
 419 {
 420         struct dirent           *de;
 421         DIR                     *dp;
 422         dns_create_resolver_t   res;
 423
 424         dp = opendir(_PATH_RESOLVER_DIR);
 425         if (dp == NULL) {
 426                 return;
 427         }
 428
 429         while ((de = readdir(dp)) != NULL) {
 430                 if (strcmp(de->d_name, ".") == 0 ||
 431                     strcmp(de->d_name, "..") == 0) continue;
 432
 433                 res = _dnsinfo_flatfile_create_resolver(_PATH_RESOLVER_DIR, de->d_name);
 434                 if (res != NULL) {
 435                         _dns_configuration_add_resolver(config, res);
 436                         _dns_resolver_free(&res);
 437                 }
 438         }
 439
 440         closedir(dp);
 441         return;
 442 }
 443
 444
 445 #ifdef MAIN
 446
 447 #include "dnsinfo_copy.c"
 448
 449 int
 450 main(int argc, char **argv)
 451 {
 452         uint8_t                 *buf;
 453         dns_config_t            *config;
 454         dns_create_config_t     create_config;
 455         _dns_config_buf_t       *config_buf;
 456         uint32_t                n_config;
 457         uint32_t                n_padding;
 458         dns_create_resolver_t   resolver;
 459
 460         resolver = _dnsinfo_flatfile_create_resolver(NULL, _PATH_RESCONF);
 461
 462         create_config = _dns_configuration_create();
 463         _dnsinfo_flatfile_add_resolvers(&create_config);
 464
 465         config_buf = (_dns_config_buf_t *)create_config;
 466         n_config  = sizeof(_dns_config_buf_t) + ntohl(config_buf->n_attribute);
 467         n_padding = ntohl(config_buf->n_padding);
 468         buf = malloc(n_config + n_padding);
 469         bcopy((void *)config_buf, buf, n_config);
 470         bzero(&buf[n_config], n_padding);
 471         config = expand_config((_dns_config_buf_t *)buf);
 472
 473         return 0;
 474 }
 475 #endif