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 <net/if.h>
  33 #include <sys/dir.h>
  34 #include <sys/types.h>
  35 #include <sys/socket.h>
  36 #include <unistd.h>
  37
  38 #include "dnsinfo.h"
  39 #include "dnsinfo_private.h"
  40 #include "dnsinfo_create.h"
  41
  42 enum {
  43         TOKEN_DOMAIN,
  44         TOKEN_FLAGS,
  45         TOKEN_INTERFACE,
  46         TOKEN_NAMESERVER,
  47         TOKEN_OPTIONS,
  48         TOKEN_PORT,
  49         TOKEN_SEARCH,
  50         TOKEN_SEARCH_ORDER,
  51         TOKEN_SORTLIST,
  52         TOKEN_TIMEOUT,
  53         TOKEN_MAX
  54 };
  55
  56 /*
  57  * tokens
  58  * The supported configuration token strings and enumerated values.
  59  */
  60 static const struct {
  61         const char      *name;
  62         int             token;
  63         int             max_count;
  64 } tokens [] = {
  65         { "domain",             TOKEN_DOMAIN,           1       },
  66         { "flags",              TOKEN_FLAGS,            1       },
  67         { "interface",          TOKEN_INTERFACE,        1       },
  68         { "nameserver",         TOKEN_NAMESERVER,       MAXNS   },
  69         { "options",            TOKEN_OPTIONS,          1       },
  70         { "port",               TOKEN_PORT,             1       },
  71         { "search",             TOKEN_SEARCH,           1       },
  72         { "search_order",       TOKEN_SEARCH_ORDER,     1       },
  73         { "sortlist",           TOKEN_SORTLIST,         1       },
  74         { "timeout",            TOKEN_TIMEOUT,          1       },
  75 };
  76
  77
  78 /*
  79  * _dnsinfo_parse_address
  80  *
  81  * Parse IP address
  82  */
  83 static struct sockaddr *
  84 _dnsinfo_parse_address(char *nameserver)
  85 {
  86         struct addrinfo *ai;
  87         struct addrinfo hints;
  88         int             res;
  89         struct sockaddr *sa     = NULL;
  90
  91         memset(&hints, 0, sizeof(hints));
  92         hints.ai_flags = AI_NUMERICHOST;
  93
  94         res = getaddrinfo(nameserver, NULL, &hints, &ai);
  95         if (res == 0) {
  96                 if ((ai->ai_family == AF_INET) || (ai->ai_family == AF_INET6)) {
  97                         sa = malloc(ai->ai_addrlen);
  98                         memcpy(sa, ai->ai_addr, ai->ai_addrlen);
  99                 }
 100                 freeaddrinfo(ai);
 101         }
 102
 103         return sa;
 104 }
 105
 106
 107 /*
 108  * _dnsinfo_parse_nameserver
 109  *
 110  * Parse arguments to the nameserver token. This is essentially a getaddrinfo(3)
 111  * with AI_NUMERICHOST. However, if the conversion fails, check if the address
 112  * contains an optional trailing '.' followed by a numeric port number.  If found,
 113  * remove the port number and retry the conversion (e.g. 127.0.0.1.55 or ::1.55).
 114  */
 115 static struct sockaddr *
 116 _dnsinfo_parse_nameserver(char *token)
 117 {
 118         char            *dot;
 119         long            number;
 120         struct sockaddr *sa;
 121
 122         sa = _dnsinfo_parse_address(token);
 123         if (sa != NULL) {
 124                 return sa;
 125         }
 126
 127         // if we could not parse address, attempt to remove
 128         // an optional trailing port number
 129         dot = strrchr(token, '.');
 130         if (dot == NULL) {
 131                 return NULL;
 132         }
 133
 134         number = strtol(dot + 1, NULL, 10);
 135         if ((number < 0) || (number > UINT16_MAX)) {
 136                 return NULL;
 137         }
 138
 139         *dot = '\0';
 140         sa = _dnsinfo_parse_address(token);
 141         if (sa != NULL) {
 142                 in_port_t       port    = htons(number);
 143
 144                 switch (sa->sa_family) {
 145                         case AF_INET :
 146                                 ((struct sockaddr_in *)sa)->sin_port = port;
 147                                 break;
 148                         case AF_INET6 :
 149                                 ((struct sockaddr_in6 *)sa)->sin6_port = port;
 150                                 break;
 151                 }
 152         }
 153
 154         return sa;
 155 }
 156
 157
 158 /*
 159  * _dnsinfo_parse_sortaddr
 160  *
 161  * Parse arguments to the sortlist token.
 162  */
 163 static dns_sortaddr_t *
 164 _dnsinfo_parse_sortaddr(char *token)
 165 {
 166         struct in_addr          addr;
 167         struct in_addr          mask;
 168         struct sockaddr         *sa;
 169         char                    *slash;
 170         dns_sortaddr_t          *sortaddr       = NULL;
 171
 172         slash = strchr(token, '/');
 173         if (slash != NULL) {
 174                 *slash = '\0';
 175         }
 176
 177         sa = _dnsinfo_parse_address(token);
 178         if (sa == NULL) {
 179                 // if we could not parse the address
 180                 goto done;
 181         } else if (sa->sa_family != AF_INET) {
 182                 // if not AF_INET
 183                 goto done;
 184         } else {
 185                 addr = ((struct sockaddr_in *)sa)->sin_addr;
 186                 free(sa);
 187                 sa = NULL;
 188         }
 189
 190         if (slash != NULL) {
 191                 sa = _dnsinfo_parse_address(slash + 1);
 192                 if (sa == NULL) {
 193                         // if we could not parse the provided mask
 194                         goto done;
 195                 } else if (sa->sa_family != AF_INET) {
 196                         // if mask not AF_INET
 197                         goto done;
 198                 } else {
 199                         mask = ((struct sockaddr_in *)sa)->sin_addr;
 200                         free(sa);
 201                         sa = NULL;
 202                 }
 203         } else {
 204                 in_addr_t       a;
 205                 in_addr_t       m;
 206
 207                 a = ntohl(addr.s_addr);
 208                 if (IN_CLASSA(a)) {
 209                         m = IN_CLASSA_NET;
 210                 } else if (IN_CLASSB(a)) {
 211                         m = IN_CLASSB_NET;
 212                 } else if (IN_CLASSC(a)) {
 213                         m = IN_CLASSC_NET;
 214                 } else {
 215                         goto done;
 216                 }
 217
 218                 mask.s_addr = htonl(m);
 219         }
 220
 221         sortaddr = malloc(sizeof(*sortaddr));
 222         sortaddr->address = addr;
 223         sortaddr->mask    = mask;
 224
 225     done :
 226
 227         if (sa != NULL) free(sa);
 228         return sortaddr;
 229 }
 230
 231
 232 /*
 233  * _dnsinfo_flatfile_create_resolver
 234  *
 235  * Create a new dns resolver configuration from the configuration file at the
 236  * specified path. (e.g. /etc/resolv.conf or /etc/resolver/apple.com)
 237  */
 238 static dns_create_resolver_t
 239 _dnsinfo_flatfile_create_resolver(const char *dir, const char *path)
 240 {
 241         char                    *buf;
 242         FILE                    *f;
 243         char                    filename[FILENAME_MAX];
 244         size_t                  len                     = 0;
 245         char                    *line                   = NULL;
 246         dns_create_resolver_t   res                     = NULL;
 247         const char              *sep                    = " \t";
 248         int                     token_count[TOKEN_MAX]  = { 0 };
 249
 250         filename[0] = 0;
 251         if (dir != NULL) {
 252                 strlcpy(filename, dir, sizeof(filename));
 253                 strlcat(filename, "/", sizeof(filename));
 254         }
 255         strlcat(filename, path, sizeof(filename));
 256
 257         f = fopen(filename, "r");
 258         if (f == NULL) return NULL;
 259
 260         while ((buf = fgetln(f, &len)) != NULL) {
 261                 int     i;
 262                 char    *lineptr;
 263                 int     max_count;
 264                 int     token;
 265                 char    *word;
 266
 267                 if (len == 0) continue;
 268                 if (buf[len-1] == '\n') buf[len-1] = '\0';
 269
 270                 line = reallocf(line, len+1);
 271                 if (line == NULL) continue;
 272
 273                 strncpy(line, buf, len);
 274                 line[len] = '\0';
 275
 276                 // parse the first word of the line (the config token)
 277                 lineptr = line;
 278                 word = strsep(&lineptr, sep);
 279                 if (word == NULL) {
 280                         // if empty line
 281                         continue;
 282                 }
 283                 if (word[0] == ';' || word[0] == '#') {
 284                         // if comment
 285                         continue;
 286                 }
 287
 288                 // translate config token to enumerated value
 289                 token = -1;
 290                 for (i = 0; i < sizeof(tokens) / sizeof(tokens[0]); i++) {
 291                         if (strcasecmp(word, tokens[i].name) == 0) {
 292                                 token     = tokens[i].token;
 293                                 max_count = tokens[i].max_count;
 294                                 break;
 295                         }
 296                 }
 297                 if (token == -1) {
 298                         // if not a recognized token
 299                         continue;
 300                 }
 301
 302                 // parse the next word of the line (the config option)
 303                 word = strsep(&lineptr, sep);
 304                 if (word == NULL) {
 305                         // if no option
 306                         continue;
 307                 }
 308                 if (++token_count[token] > max_count) {
 309                         // if too many options
 310                         continue;
 311                 }
 312
 313                 // create resolver
 314                 if (res == NULL) {
 315                         res = _dns_resolver_create();
 316                         if (res == NULL) {
 317                                 // if we could not create a resolver
 318                                 goto done;
 319                         }
 320                 }
 321
 322                 switch (token) {
 323                         case TOKEN_DOMAIN: {
 324                                 size_t  len;
 325
 326                                 len = strlen(word);
 327                                 while ((len > 0) && (word[len - 1] == '.')) {
 328                                         // trim trailing '.'
 329                                         word[--len] = '\0';
 330                                 }
 331                                 if (len > 0) {
 332                                         _dns_resolver_set_domain(&res, word);
 333                                 }
 334                                 break;
 335                         }
 336
 337                         case TOKEN_FLAGS: {
 338                                 uint32_t        flags   = 0;
 339
 340                                 while (word != NULL) {
 341                                         if (word[0] != '\0') {
 342                                                 if (strcasecmp(word, "scoped") == 0) {
 343                                                         flags |= DNS_RESOLVER_FLAGS_SCOPED;
 344                                                 }
 345                                         }
 346                                         word = strsep(&lineptr, sep);
 347                                 }
 348
 349                                 if (flags != 0) {
 350                                         _dns_resolver_set_flags(&res, flags);
 351                                 }
 352                                 break;
 353                         }
 354
 355                         case TOKEN_INTERFACE: {
 356                                 unsigned int    if_index;
 357
 358                                 if_index = if_nametoindex(word);
 359                                 if (if_index > 0) {
 360                                         _dns_resolver_set_if_index(&res, if_index);
 361                                 }
 362                                 break;
 363                         }
 364
 365                         case TOKEN_NAMESERVER: {
 366                                 struct sockaddr *sa;
 367
 368                                 sa = _dnsinfo_parse_nameserver(word);
 369                                 if (sa != NULL) {
 370                                         _dns_resolver_add_nameserver(&res, sa);
 371                                         free(sa);
 372                                 }
 373                                 break;
 374                         }
 375
 376                         case TOKEN_OPTIONS: {
 377                                 char    *options        = NULL;
 378
 379                                 while (word != NULL) {
 380                                         if (word[0] != '\0') {
 381                                                 if (options == NULL) {
 382                                                         options = malloc(len+1);
 383                                                         if (options == NULL) break;
 384
 385                                                         strlcpy(options, word, len+1);
 386                                                 } else {
 387                                                         strlcat(options, " ", len+1);
 388                                                         strlcat(options, word, len+1);
 389                                                 }
 390                                         }
 391                                         word = strsep(&lineptr, sep);
 392                                 }
 393
 394                                 if (options != NULL) {
 395                                         _dns_resolver_set_options(&res, options);
 396                                         free(options);
 397                                 }
 398                                 break;
 399                         }
 400
 401                         case TOKEN_PORT: {
 402                                 long    number  = -1;
 403
 404                                 number = strtol(word, NULL, 0);
 405                                 if (number < 0 || number > UINT16_MAX) break;
 406                                 _dns_resolver_set_port(&res, number);
 407                                 break;
 408                         }
 409
 410                         case TOKEN_SEARCH: {
 411                                 int     n       = 0;
 412
 413                                 // multiple search domains are supported
 414                                 while ((word != NULL) && (n++ < MAXDNSRCH)) {
 415                                         size_t  len;
 416
 417                                         len = strlen(word);
 418                                         while ((len > 0) && (word[len - 1] == '.')) {
 419                                                 // trim trailing '.'
 420                                                 word[--len] = '\0';
 421                                         }
 422                                         if (len > 0) {
 423                                                 _dns_resolver_add_search(&res, word);
 424                                         }
 425                                         word = strsep(&lineptr, sep);
 426                                 }
 427                                 break;
 428                         }
 429
 430                         case TOKEN_SEARCH_ORDER: {
 431                                 long    number  = -1;
 432
 433                                 number = strtol(word, NULL, 0);
 434                                 if (number < 0 || number > UINT32_MAX) break;
 435                                 _dns_resolver_set_order(&res, number);
 436                                 break;
 437                         }
 438
 439                         case TOKEN_SORTLIST: {
 440                                 int     n       = 0;
 441
 442                                 while ((word != NULL) && (n++ < MAXRESOLVSORT)) {
 443                                         dns_sortaddr_t  *sortaddr;
 444
 445                                         sortaddr = _dnsinfo_parse_sortaddr(word);
 446                                         if (sortaddr == NULL) break;
 447                                         _dns_resolver_add_sortaddr(&res, sortaddr);
 448                                         free(sortaddr);
 449                                         word = strsep(&lineptr, sep);
 450                                 }
 451                                 break;
 452                         }
 453
 454                         case TOKEN_TIMEOUT: {
 455                                 long    number  = -1;
 456
 457                                 number = strtol(word, NULL, 0);
 458                                 if (number < 0 || number > UINT32_MAX) break;
 459                                 _dns_resolver_set_timeout(&res, number);
 460                                 break;
 461                         }
 462                 }
 463         }
 464         if (line != NULL) free(line);
 465
 466         // set the domain to the basename of the path if not specified
 467         if ((res != NULL) && (token_count[TOKEN_DOMAIN] == 0)) {
 468                 const char      *domain;
 469
 470                 domain = strrchr(path, '/');
 471                 if (domain == NULL) {
 472                         domain = path;
 473                 } else {
 474                         domain = domain + 1;
 475                 }
 476                 _dns_resolver_set_domain(&res, domain);
 477         }
 478
 479     done :
 480
 481         fclose(f);
 482         return res;
 483 }
 484
 485
 486 /*
 487  * _dnsinfo_flatfile_add_resolvers
 488  *
 489  * Parse the files in the resolver config directory (/etc/resolver) and add each
 490  * resolver to the dns config.
 491  */
 492 void
 493 _dnsinfo_flatfile_add_resolvers(dns_create_config_t *config)
 494 {
 495         struct dirent           *de;
 496         DIR                     *dp;
 497         dns_create_resolver_t   res;
 498
 499         dp = opendir(_PATH_RESOLVER_DIR);
 500         if (dp == NULL) {
 501                 return;
 502         }
 503
 504         while ((de = readdir(dp)) != NULL) {
 505                 if (strcmp(de->d_name, ".") == 0 ||
 506                     strcmp(de->d_name, "..") == 0) continue;
 507
 508                 res = _dnsinfo_flatfile_create_resolver(_PATH_RESOLVER_DIR, de->d_name);
 509                 if (res != NULL) {
 510                         _dns_configuration_add_resolver(config, res);
 511                         _dns_resolver_free(&res);
 512                 }
 513         }
 514
 515         closedir(dp);
 516         return;
 517 }
 518
 519
 520 #ifdef  MAIN
 521 #undef  MAIN
 522
 523 #include "dnsinfo_copy.c"
 524
 525 int
 526 main(int argc, char **argv)
 527 {
 528         uint8_t                 *buf;
 529         dns_config_t            *config;
 530         dns_create_config_t     create_config;
 531         _dns_config_buf_t       *config_buf;
 532         uint32_t                n_config;
 533         uint32_t                n_padding;
 534         dns_create_resolver_t   resolver;
 535
 536         resolver = _dnsinfo_flatfile_create_resolver(NULL, _PATH_RESCONF);
 537
 538         create_config = _dns_configuration_create();
 539         _dnsinfo_flatfile_add_resolvers(&create_config);
 540
 541         config_buf = (_dns_config_buf_t *)create_config;
 542         n_config  = sizeof(_dns_config_buf_t) + ntohl(config_buf->n_attribute);
 543         n_padding = ntohl(config_buf->n_padding);
 544         buf = malloc(n_config + n_padding);
 545         bcopy((void *)config_buf, buf, n_config);
 546         bzero(&buf[n_config], n_padding);
 547         config = expand_config((_dns_config_buf_t *)buf);
 548
 549         return 0;
 550 }
 551
 552 #endif