dnsinfo/dnsinfo_flatfile.c

   1 /*
   2  * Copyright (c) 2009, 2011 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                                 /* ALIGN: cast ok, sockaddr was malloc'd */
 147                                 ((struct sockaddr_in *)(void *)sa)->sin_port = port;
 148                                 break;
 149                         case AF_INET6 :
 150                                 /* ALIGN: cast ok, sockaddr was malloc'd */
 151                                 ((struct sockaddr_in6 *)(void *)sa)->sin6_port = port;
 152                                 break;
 153                 }
 154         }
 155
 156         return sa;
 157 }
 158
 159
 160 /*
 161  * _dnsinfo_parse_sortaddr
 162  *
 163  * Parse arguments to the sortlist token.
 164  */
 165 static dns_sortaddr_t *
 166 _dnsinfo_parse_sortaddr(char *token)
 167 {
 168         struct in_addr          addr;
 169         struct in_addr          mask;
 170         struct sockaddr         *sa;
 171         char                    *slash;
 172         dns_sortaddr_t          *sortaddr       = NULL;
 173
 174         slash = strchr(token, '/');
 175         if (slash != NULL) {
 176                 *slash = '\0';
 177         }
 178
 179         sa = _dnsinfo_parse_address(token);
 180         if (sa == NULL) {
 181                 // if we could not parse the address
 182                 goto done;
 183         } else if (sa->sa_family != AF_INET) {
 184                 // if not AF_INET
 185                 goto done;
 186         } else {
 187                 /* ALIGN: cast ok, sockaddr was malloc'd */
 188                 addr = ((struct sockaddr_in *)(void *)sa)->sin_addr;
 189                 free(sa);
 190                 sa = NULL;
 191         }
 192
 193         if (slash != NULL) {
 194                 sa = _dnsinfo_parse_address(slash + 1);
 195                 if (sa == NULL) {
 196                         // if we could not parse the provided mask
 197                         goto done;
 198                 } else if (sa->sa_family != AF_INET) {
 199                         // if mask not AF_INET
 200                         goto done;
 201                 } else {
 202                         /* ALIGN: cast ok, sockaddr was malloc'd */
 203                         mask = ((struct sockaddr_in *)(void *)sa)->sin_addr;
 204                         free(sa);
 205                         sa = NULL;
 206                 }
 207         } else {
 208                 in_addr_t       a;
 209                 in_addr_t       m;
 210
 211                 a = ntohl(addr.s_addr);
 212                 if (IN_CLASSA(a)) {
 213                         m = IN_CLASSA_NET;
 214                 } else if (IN_CLASSB(a)) {
 215                         m = IN_CLASSB_NET;
 216                 } else if (IN_CLASSC(a)) {
 217                         m = IN_CLASSC_NET;
 218                 } else {
 219                         goto done;
 220                 }
 221
 222                 mask.s_addr = htonl(m);
 223         }
 224
 225         sortaddr = malloc(sizeof(*sortaddr));
 226         sortaddr->address = addr;
 227         sortaddr->mask    = mask;
 228
 229     done :
 230
 231         if (sa != NULL) free(sa);
 232         return sortaddr;
 233 }
 234
 235
 236 /*
 237  * _dnsinfo_flatfile_create_resolver
 238  *
 239  * Create a new dns resolver configuration from the configuration file at the
 240  * specified path. (e.g. /etc/resolv.conf or /etc/resolver/apple.com)
 241  */
 242 static dns_create_resolver_t
 243 _dnsinfo_flatfile_create_resolver(const char *dir, const char *path)
 244 {
 245         char                    *buf;
 246         FILE                    *f;
 247         char                    filename[FILENAME_MAX];
 248         size_t                  len                     = 0;
 249         char                    *line                   = NULL;
 250         dns_create_resolver_t   res                     = NULL;
 251         const char              *sep                    = " \t";
 252         int                     token_count[TOKEN_MAX]  = { 0 };
 253
 254         filename[0] = 0;
 255         if (dir != NULL) {
 256                 strlcpy(filename, dir, sizeof(filename));
 257                 strlcat(filename, "/", sizeof(filename));
 258         }
 259         strlcat(filename, path, sizeof(filename));
 260
 261         f = fopen(filename, "r");
 262         if (f == NULL) return NULL;
 263
 264         while ((buf = fgetln(f, &len)) != NULL) {
 265                 int     i;
 266                 char    *lineptr;
 267                 int     max_count;
 268                 int     token;
 269                 char    *word;
 270
 271                 if (len == 0) continue;
 272                 if (buf[len-1] == '\n') buf[len-1] = '\0';
 273
 274                 line = reallocf(line, len+1);
 275                 if (line == NULL) continue;
 276
 277                 strncpy(line, buf, len);
 278                 line[len] = '\0';
 279
 280                 // parse the first word of the line (the config token)
 281                 lineptr = line;
 282                 word = strsep(&lineptr, sep);
 283                 if (word == NULL) {
 284                         // if empty line
 285                         continue;
 286                 }
 287                 if (word[0] == ';' || word[0] == '#') {
 288                         // if comment
 289                         continue;
 290                 }
 291
 292                 // translate config token to enumerated value
 293                 token = -1;
 294                 for (i = 0; i < sizeof(tokens) / sizeof(tokens[0]); i++) {
 295                         if (strcasecmp(word, tokens[i].name) == 0) {
 296                                 token     = tokens[i].token;
 297                                 max_count = tokens[i].max_count;
 298                                 break;
 299                         }
 300                 }
 301                 if (token == -1) {
 302                         // if not a recognized token
 303                         continue;
 304                 }
 305
 306                 // parse the next word of the line (the config option)
 307                 word = strsep(&lineptr, sep);
 308                 if (word == NULL) {
 309                         // if no option
 310                         continue;
 311                 }
 312                 if (++token_count[token] > max_count) {
 313                         // if too many options
 314                         continue;
 315                 }
 316
 317                 // create resolver
 318                 if (res == NULL) {
 319                         res = _dns_resolver_create();
 320                         if (res == NULL) {
 321                                 // if we could not create a resolver
 322                                 goto done;
 323                         }
 324                 }
 325
 326                 switch (token) {
 327                         case TOKEN_DOMAIN: {
 328                                 size_t  len;
 329
 330                                 len = strlen(word);
 331                                 while ((len > 0) && (word[len - 1] == '.')) {
 332                                         // trim trailing '.'
 333                                         word[--len] = '\0';
 334                                 }
 335                                 if (len > 0) {
 336                                         _dns_resolver_set_domain(&res, word);
 337                                 }
 338                                 break;
 339                         }
 340
 341                         case TOKEN_FLAGS: {
 342                                 uint32_t        flags   = 0;
 343
 344                                 while (word != NULL) {
 345                                         if (word[0] != '\0') {
 346                                                 if (strcasecmp(word, "scoped") == 0) {
 347                                                         flags |= DNS_RESOLVER_FLAGS_SCOPED;
 348                                                 }
 349                                         }
 350                                         word = strsep(&lineptr, sep);
 351                                 }
 352
 353                                 if (flags != 0) {
 354                                         _dns_resolver_set_flags(&res, flags);
 355                                 }
 356                                 break;
 357                         }
 358
 359                         case TOKEN_INTERFACE: {
 360                                 unsigned int    if_index;
 361
 362                                 if_index = if_nametoindex(word);
 363                                 if (if_index > 0) {
 364                                         _dns_resolver_set_if_index(&res, if_index);
 365                                 }
 366                                 break;
 367                         }
 368
 369                         case TOKEN_NAMESERVER: {
 370                                 struct sockaddr *sa;
 371
 372                                 sa = _dnsinfo_parse_nameserver(word);
 373                                 if (sa != NULL) {
 374                                         _dns_resolver_add_nameserver(&res, sa);
 375                                         free(sa);
 376                                 }
 377                                 break;
 378                         }
 379
 380                         case TOKEN_OPTIONS: {
 381                                 char    *options        = NULL;
 382
 383                                 while (word != NULL) {
 384                                         if (word[0] != '\0') {
 385                                                 if (options == NULL) {
 386                                                         options = malloc(len+1);
 387                                                         if (options == NULL) break;
 388
 389                                                         strlcpy(options, word, len+1);
 390                                                 } else {
 391                                                         strlcat(options, " ", len+1);
 392                                                         strlcat(options, word, len+1);
 393                                                 }
 394                                         }
 395                                         word = strsep(&lineptr, sep);
 396                                 }
 397
 398                                 if (options != NULL) {
 399                                         _dns_resolver_set_options(&res, options);
 400                                         free(options);
 401                                 }
 402                                 break;
 403                         }
 404
 405                         case TOKEN_PORT: {
 406                                 long    number  = -1;
 407
 408                                 number = strtol(word, NULL, 0);
 409                                 if (number < 0 || number > UINT16_MAX) break;
 410                                 _dns_resolver_set_port(&res, number);
 411                                 break;
 412                         }
 413
 414                         case TOKEN_SEARCH: {
 415                                 int     n       = 0;
 416
 417                                 // multiple search domains are supported
 418                                 while ((word != NULL) && (n++ < MAXDNSRCH)) {
 419                                         size_t  len;
 420
 421                                         len = strlen(word);
 422                                         while ((len > 0) && (word[len - 1] == '.')) {
 423                                                 // trim trailing '.'
 424                                                 word[--len] = '\0';
 425                                         }
 426                                         if (len > 0) {
 427                                                 _dns_resolver_add_search(&res, word);
 428                                         }
 429                                         word = strsep(&lineptr, sep);
 430                                 }
 431                                 break;
 432                         }
 433
 434                         case TOKEN_SEARCH_ORDER: {
 435                                 long    number  = -1;
 436
 437                                 number = strtol(word, NULL, 0);
 438                                 if (number < 0 || number > UINT32_MAX) break;
 439                                 _dns_resolver_set_order(&res, number);
 440                                 break;
 441                         }
 442
 443                         case TOKEN_SORTLIST: {
 444                                 int     n       = 0;
 445
 446                                 while ((word != NULL) && (n++ < MAXRESOLVSORT)) {
 447                                         dns_sortaddr_t  *sortaddr;
 448
 449                                         sortaddr = _dnsinfo_parse_sortaddr(word);
 450                                         if (sortaddr == NULL) break;
 451                                         _dns_resolver_add_sortaddr(&res, sortaddr);
 452                                         free(sortaddr);
 453                                         word = strsep(&lineptr, sep);
 454                                 }
 455                                 break;
 456                         }
 457
 458                         case TOKEN_TIMEOUT: {
 459                                 long    number  = -1;
 460
 461                                 number = strtol(word, NULL, 0);
 462                                 if (number < 0 || number > UINT32_MAX) break;
 463                                 _dns_resolver_set_timeout(&res, number);
 464                                 break;
 465                         }
 466                 }
 467         }
 468         if (line != NULL) free(line);
 469
 470         // set the domain to the basename of the path if not specified
 471         if ((res != NULL) && (token_count[TOKEN_DOMAIN] == 0)) {
 472                 const char      *domain;
 473
 474                 domain = strrchr(path, '/');
 475                 if (domain == NULL) {
 476                         domain = path;
 477                 } else {
 478                         domain = domain + 1;
 479                 }
 480                 _dns_resolver_set_domain(&res, domain);
 481         }
 482
 483     done :
 484
 485         fclose(f);
 486         return res;
 487 }
 488
 489
 490 /*
 491  * _dnsinfo_flatfile_add_resolvers
 492  *
 493  * Parse the files in the resolver config directory (/etc/resolver) and add each
 494  * resolver to the dns config.
 495  */
 496 void
 497 _dnsinfo_flatfile_add_resolvers(dns_create_config_t *config)
 498 {
 499         struct dirent           *de;
 500         DIR                     *dp;
 501         dns_create_resolver_t   res;
 502
 503         dp = opendir(_PATH_RESOLVER_DIR);
 504         if (dp == NULL) {
 505                 return;
 506         }
 507
 508         while ((de = readdir(dp)) != NULL) {
 509                 if (strcmp(de->d_name, ".") == 0 ||
 510                     strcmp(de->d_name, "..") == 0) continue;
 511
 512                 res = _dnsinfo_flatfile_create_resolver(_PATH_RESOLVER_DIR, de->d_name);
 513                 if (res != NULL) {
 514                         _dns_configuration_add_resolver(config, res);
 515                         _dns_resolver_free(&res);
 516                 }
 517         }
 518
 519         closedir(dp);
 520         return;
 521 }
 522
 523
 524 #ifdef  MAIN
 525 #undef  MAIN
 526
 527 #include "dnsinfo_copy.c"
 528
 529 int
 530 main(int argc, char **argv)
 531 {
 532         uint8_t                 *buf;
 533         dns_config_t            *config;
 534         dns_create_config_t     create_config;
 535         _dns_config_buf_t       *config_buf;
 536         uint32_t                n_config;
 537         uint32_t                n_padding;
 538         dns_create_resolver_t   resolver;
 539
 540         resolver = _dnsinfo_flatfile_create_resolver(NULL, _PATH_RESCONF);
 541
 542         create_config = _dns_configuration_create();
 543         _dnsinfo_flatfile_add_resolvers(&create_config);
 544
 545         config_buf = (_dns_config_buf_t *)create_config;
 546         n_config  = sizeof(_dns_config_buf_t) + ntohl(config_buf->n_attribute);
 547         n_padding = ntohl(config_buf->n_padding);
 548         buf = malloc(n_config + n_padding);
 549         bcopy((void *)config_buf, buf, n_config);
 550         bzero(&buf[n_config], n_padding);
 551         config = expand_config((_dns_config_buf_t *)buf);
 552
 553         return 0;
 554 }
 555
 556 #endif