lib/rfc3596.c

   1 /*
   2  * $Id$
   3  *
   4  * Low level DNS protocol routines
   5  * AUTHOR: Amos Jeffries, Rafael Martinez Torres
   6  *
   7  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   8  * ----------------------------------------------------------
   9  *
  10  *  Squid is the result of efforts by numerous individuals from
  11  *  the Internet community; see the CONTRIBUTORS file for full
  12  *  details.   Many organizations have provided support for Squid's
  13  *  development; see the SPONSORS file for full details.  Squid is
  14  *  Copyrighted (C) 2001 by the Regents of the University of
  15  *  California; see the COPYRIGHT file for full details.  Squid
  16  *  incorporates software developed and/or copyrighted by other
  17  *  sources; see the CREDITS file for full details.
  18  *
  19  *  This code is copyright (C) 2007 by Treehouse Networks Ltd of
  20  *  New Zealand. It is published and Lisenced as an extension of
  21  *  squid under the same conditions as the main squid application.
  22  *
  23  *  This program is free software; you can redistribute it and/or modify
  24  *  it under the terms of the GNU General Public License as published by
  25  *  the Free Software Foundation; either version 2 of the License, or
  26  *  (at your option) any later version.
  27  *
  28  *  This program is distributed in the hope that it will be useful,
  29  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  30  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  31  *  GNU General Public License for more details.
  32  *
  33  *  You should have received a copy of the GNU General Public License
  34  *  along with this program; if not, write to the Free Software
  35  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  36  *
  37  */
  38
  39 /*
  40  * KNOWN BUGS:
  41  *
  42  * UDP replies with TC set should be retried via TCP
  43  */
  44
  45 /**
  46  * April 2007
  47  *
  48  * Provides RFC3596 functions to handle purely IPv6 DNS.
  49  * Adds AAAA and IPv6 PTR records.
  50  * Other IPv6 records are not mentioned by this RFC.
  51  *
  52  * IPv4 equivalents are taken care of by the RFC1035 library.
  53  * Where one protocol lookup must be followed by another, the caller
  54  * is resposible for the order and handling of the lookups.
  55  *
  56  */
  57
  58 #include "config.h"
  59 #include "compat/inet_pton.h"
  60 #include "util.h"
  61
  62 #if HAVE_STDIO_H
  63 #include <stdio.h>
  64 #endif
  65 #if HAVE_UNISTD_H
  66 #include <unistd.h>
  67 #endif
  68 #if HAVE_MEMORY_H
  69 #include <memory.h>
  70 #endif
  71 #if HAVE_ASSERT_H
  72 #include <assert.h>
  73 #endif
  74 #if HAVE_NETINET_IN_H
  75 #include <netinet/in.h>
  76 #endif
  77 #if HAVE_STRINGS_H
  78 #include <strings.h>
  79 #endif
  80
  81 #include "rfc3596.h"
  82 #include "rfc2671.h"
  83
  84 #ifndef SQUID_RFC1035_H
  85 #error RFC3596 Library depends on RFC1035
  86 #endif
  87
  88 /**
  89  * Builds a message buffer with a QUESTION to lookup records
  90  * for a hostname.  Caller must allocate 'buf' which should
  91  * probably be at least 512 octets.  The 'szp' initially
  92  * specifies the size of the buffer, on return it contains
  93  * the size of the message (i.e. how much to write).
  94  * Returns the size of the query
  95  */
  96 ssize_t
  97 rfc3596BuildHostQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, int qtype, ssize_t edns_sz)
  98 {
  99     static rfc1035_message h;
 100     size_t offset = 0;
 101     memset(&h, '\0', sizeof(h));
 102     h.id = qid;
 103     h.qr = 0;
 104     h.rd = 1;
 105     h.opcode = 0;               /* QUERY */
 106     h.qdcount = (unsigned int) 1;
 107     h.arcount = (edns_sz > 0 ? 1 : 0);
 108     offset += rfc1035HeaderPack(buf + offset, sz - offset, &h);
 109     offset += rfc1035QuestionPack(buf + offset,
 110                                   sz - offset,
 111                                   hostname,
 112                                   qtype,
 113                                   RFC1035_CLASS_IN);
 114     if (edns_sz > 0)
 115         offset += rfc2671RROptPack(buf + offset, sz - offset, edns_sz);
 116
 117     if (query) {
 118         query->qtype = qtype;
 119         query->qclass = RFC1035_CLASS_IN;
 120         xstrncpy(query->name, hostname, sizeof(query->name));
 121     }
 122
 123     assert(offset <= sz);
 124     return offset;
 125 }
 126
 127 /**
 128  * Builds a message buffer with a QUESTION to lookup A records
 129  * for a hostname.  Caller must allocate 'buf' which should
 130  * probably be at least 512 octets.  The 'szp' initially
 131  * specifies the size of the buffer, on return it contains
 132  * the size of the message (i.e. how much to write).
 133  * \return the size of the query
 134  */
 135 ssize_t
 136 rfc3596BuildAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz)
 137 {
 138     return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_A, edns_sz);
 139 }
 140
 141 /**
 142  * Builds a message buffer with a QUESTION to lookup AAAA records
 143  * for a hostname.  Caller must allocate 'buf' which should
 144  * probably be at least 512 octets.  The 'szp' initially
 145  * specifies the size of the buffer, on return it contains
 146  * the size of the message (i.e. how much to write).
 147  * \return the size of the query
 148  */
 149 ssize_t
 150 rfc3596BuildAAAAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz)
 151 {
 152     return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_AAAA, edns_sz);
 153 }
 154
 155
 156 /**
 157  * Builds a message buffer with a QUESTION to lookup PTR records
 158  * for an address.  Caller must allocate 'buf' which should
 159  * probably be at least 512 octets.  The 'szp' initially
 160  * specifies the size of the buffer, on return it contains
 161  * the size of the message (i.e. how much to write).
 162  * \return the size of the query
 163  */
 164 ssize_t
 165 rfc3596BuildPTRQuery4(const struct in_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz)
 166 {
 167     static char rev[RFC1035_MAXHOSTNAMESZ];
 168     unsigned int i;
 169
 170     i = (unsigned int) ntohl(addr.s_addr);
 171     snprintf(rev, RFC1035_MAXHOSTNAMESZ, "%u.%u.%u.%u.in-addr.arpa.",
 172              i & 255,
 173              (i >> 8) & 255,
 174              (i >> 16) & 255,
 175              (i >> 24) & 255);
 176
 177     return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR, edns_sz);
 178 }
 179
 180 ssize_t
 181 rfc3596BuildPTRQuery6(const struct in6_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz)
 182 {
 183     static char rev[RFC1035_MAXHOSTNAMESZ];
 184     const uint8_t* r = addr.s6_addr;
 185     char* p = rev;
 186     int i; /* NP: MUST allow signed for loop termination. */
 187
 188     /* work from the raw addr field. anything else may have representation changes. */
 189     /* The sin6_port and sin6_addr members shall be in network byte order. */
 190     for (i = 15; i >= 0; i--, p+=4) {
 191         snprintf(p, 5, "%1x.%1x.", ((r[i]>>4)&0xf), (r[i])&0xf );
 192     }
 193
 194     snprintf(p,10,"ip6.arpa.");
 195
 196     return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR, edns_sz);
 197 }
 198
 199
 200 #if DRIVER
 201
 202 /* driver needs the rfc1035 code _without_ the main() */
 203 #  define main(a,b) rfc1035_main(a,b)
 204 #  include "rfc1035.c"
 205 #  undef main(a,b)
 206
 207 #include <sys/socket.h>
 208
 209 int
 210 main(int argc, char *argv[])
 211 {
 212 #define PACKET_BUFSZ            1024
 213     char input[PACKET_BUFSZ];
 214     char buf[PACKET_BUFSZ];
 215     char rbuf[PACKET_BUFSZ];
 216     size_t sz = PACKET_BUFSZ;
 217     unsigned short sid, sidb;
 218     int s;
 219     int rl;
 220     ssize_t edns_max = -1;
 221
 222     struct sockaddr* S;
 223     int var = 1;
 224
 225     if ( argc < 3 || argc > 4) {
 226         fprintf(stderr, "usage: %s [-6|-4] ip port\n", argv[0]);
 227         return 1;
 228     }
 229
 230     setbuf(stdout, NULL);
 231     setbuf(stderr, NULL);
 232
 233     if (argv[var][0] == '-') {
 234         if (argv[var][1] == '4')
 235             prefer = AF_INET;
 236         else if (argv[var][1] == '6')
 237             prefer = AF_INET6;
 238         else if (argv[var][1] == 'E')
 239             edns_max = atoi(argv[var++]);
 240         else {
 241             fprintf(stderr, "usage: %s [-6|-4] [-E packet-size] ip port\n", argv[0]);
 242             fprintf(stderr, "  EDNS packets my be up to %d\n", PACKET_BUFSZ);
 243             return 1;
 244         }
 245
 246         var++;
 247     }
 248
 249     s = socket(PF_INET, SOCK_DGRAM, 0);
 250
 251     if (s < 0) {
 252         perror("socket");
 253         return 1;
 254     }
 255
 256
 257     memset(&S, '\0', sizeof(S));
 258
 259     if (prefer == 6) {
 260         S = (struct sockaddr *) new sockaddr_in6;
 261         memset(S,0,sizeof(struct sockaddr_in6));
 262
 263         ((struct sockaddr_in6 *)S)->sin6_family = AF_INET6;
 264         ((struct sockaddr_in6 *)S)->sin6_port = htons(atoi(argv[var+1]));
 265
 266         if ( ! inet_pton(AF_INET6, argv[var], &((struct sockaddr_in6 *)S)->sin6_addr.s_addr) ) {
 267             perror("listen address");
 268             return 1;
 269         }
 270
 271         s = socket(PF_INET6, SOCK_DGRAM, 0);
 272     } else {
 273         S = (struct sockaddr *) new sockaddr_in;
 274         memset(S,0,sizeof(struct sockaddr_in));
 275
 276         ((struct sockaddr_in *)S)->sin_family = AF_INET;
 277         ((struct sockaddr_in *)S)->sin_port = htons(atoi(argv[var+1]));
 278
 279         if ( ! inet_pton(AF_INET, argv[var], &((struct sockaddr_in *)S)->sin_addr.s_addr) )
 280             perror("listen address");
 281         return 1;
 282     }
 283 }
 284
 285 while (fgets(input, PACKET_BUFSZ, stdin))
 286 {
 287
 288     struct in6_addr junk6;
 289
 290     struct in_addr junk4;
 291     strtok(input, "\r\n");
 292     memset(buf, '\0', PACKET_BUFSZ);
 293     sz = PACKET_BUFSZ;
 294
 295     if (inet_pton(AF_INET6, input, &junk6)) {
 296         sid = rfc1035BuildPTRQuery6(junk6, buf, &sz, edns_max);
 297         sidb=0;
 298     } else if (inet_pton(AF_INET, input, &junk4)) {
 299         sid = rfc1035BuildPTRQuery4(junk4, buf, &sz, edns_max);
 300         sidb=0;
 301     } else {
 302         sid = rfc1035BuildAAAAQuery(input, buf, &sz, edns_max);
 303         sidb = rfc1035BuildAQuery(input, buf, &sz, edns_max);
 304     }
 305
 306     sendto(s, buf, sz, 0, S, sizeof(*S));
 307
 308     do {
 309         fd_set R;
 310
 311         struct timeval to;
 312         FD_ZERO(&R);
 313         FD_SET(s, &R);
 314         to.tv_sec = 10;
 315         to.tv_usec = 0;
 316         rl = select(s + 1, &R, NULL, NULL, &to);
 317     } while (0);
 318
 319     if (rl < 1) {
 320         printf("TIMEOUT\n");
 321         continue;
 322     }
 323
 324     memset(rbuf, '\0', PACKET_BUFSZ);
 325     rl = recv(s, rbuf, PACKET_BUFSZ, 0);
 326     {
 327         unsigned short rid = 0;
 328         int i;
 329         int n;
 330         rfc1035_rr *answers = NULL;
 331         n = rfc1035AnswersUnpack(rbuf,
 332                                  rl,
 333                                  &answers,
 334                                  &rid);
 335
 336         if (n < 0) {
 337             printf("ERROR %d\n", -n);
 338         } else if (rid != sid && rid != sidb) {
 339             printf("ERROR, ID mismatch (%#hx, %#hx)\n", sid, rid);
 340             printf("ERROR, ID mismatch (%#hx, %#hx)\n", sidb, rid);
 341         } else {
 342             printf("%d answers\n", n);
 343
 344             for (i = 0; i < n; i++) {
 345                 if (answers[i].type == RFC1035_TYPE_A) {
 346
 347                     struct in_addr a;
 348                     char tmp[16];
 349                     memcpy(&a, answers[i].rdata, 4);
 350                     printf("A\t%d\t%s\n", answers[i].ttl, inet_ntop(AF_INET,&a,tmp,16));
 351                 } else if (answers[i].type == RFC1035_TYPE_AAAA) {
 352
 353                     struct in6_addr a;
 354                     char tmp[INET6_ADDRSTRLEN];
 355                     memcpy(&a, answers[i].rdata, 16);
 356                     printf("AAAA\t%d\t%s\n", answers[i].ttl, inet_ntop(AF_INET6,&a,tmp,sizeof(tmp)));
 357                 } else if (answers[i].type == RFC1035_TYPE_PTR) {
 358                     char ptr[RFC1035_MAXHOSTNAMESZ];
 359                     strncpy(ptr, answers[i].rdata, answers[i].rdlength);
 360                     printf("PTR\t%d\t%s\n", answers[i].ttl, ptr);
 361                 } else if (answers[i].type == RFC1035_TYPE_CNAME) {
 362                     char ptr[RFC1035_MAXHOSTNAMESZ];
 363                     strncpy(ptr, answers[i].rdata, answers[i].rdlength);
 364                     printf("CNAME\t%d\t%s\n", answers[i].ttl, ptr);
 365                 } else {
 366                     fprintf(stderr, "can't print answer type %d\n",
 367                             (int) answers[i].type);
 368                 }
 369             }
 370         }
 371     }
 372 }
 373
 374 return 0;
 375 }
 376
 377 #endif