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
  83 #ifndef SQUID_RFC1035_H
  84 #error RFC3596 Library depends on RFC1035
  85 #endif
  86
  87 /**
  88  * Builds a message buffer with a QUESTION to lookup records
  89  * for a hostname.  Caller must allocate 'buf' which should
  90  * probably be at least 512 octets.  The 'szp' initially
  91  * specifies the size of the buffer, on return it contains
  92  * the size of the message (i.e. how much to write).
  93  * Returns the size of the query
  94  */
  95 ssize_t
  96 rfc3596BuildHostQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, int qtype)
  97 {
  98     static rfc1035_message h;
  99     size_t offset = 0;
 100     memset(&h, '\0', sizeof(h));
 101     h.id = qid;
 102     h.qr = 0;
 103     h.rd = 1;
 104     h.opcode = 0;               /* QUERY */
 105     h.qdcount = (unsigned int) 1;
 106     offset += rfc1035HeaderPack(buf + offset, sz - offset, &h);
 107     offset += rfc1035QuestionPack(buf + offset,
 108                                   sz - offset,
 109                                   hostname,
 110                                   qtype,
 111                                   RFC1035_CLASS_IN);
 112
 113     if (query) {
 114         query->qtype = qtype;
 115         query->qclass = RFC1035_CLASS_IN;
 116         xstrncpy(query->name, hostname, sizeof(query->name));
 117     }
 118
 119     assert(offset <= sz);
 120     return offset;
 121 }
 122
 123 /**
 124  * Builds a message buffer with a QUESTION to lookup A records
 125  * for a hostname.  Caller must allocate 'buf' which should
 126  * probably be at least 512 octets.  The 'szp' initially
 127  * specifies the size of the buffer, on return it contains
 128  * the size of the message (i.e. how much to write).
 129  * \return the size of the query
 130  */
 131 ssize_t
 132 rfc3596BuildAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query)
 133 {
 134     return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_A);
 135 }
 136
 137 /**
 138  * Builds a message buffer with a QUESTION to lookup AAAA records
 139  * for a hostname.  Caller must allocate 'buf' which should
 140  * probably be at least 512 octets.  The 'szp' initially
 141  * specifies the size of the buffer, on return it contains
 142  * the size of the message (i.e. how much to write).
 143  * \return the size of the query
 144  */
 145 ssize_t
 146 rfc3596BuildAAAAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query)
 147 {
 148     return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_AAAA);
 149 }
 150
 151
 152 /**
 153  * Builds a message buffer with a QUESTION to lookup PTR records
 154  * for an address.  Caller must allocate 'buf' which should
 155  * probably be at least 512 octets.  The 'szp' initially
 156  * specifies the size of the buffer, on return it contains
 157  * the size of the message (i.e. how much to write).
 158  * \return the size of the query
 159  */
 160 ssize_t
 161
 162 rfc3596BuildPTRQuery4(const struct in_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query)
 163 {
 164     static char rev[RFC1035_MAXHOSTNAMESZ];
 165     unsigned int i;
 166
 167     i = (unsigned int) ntohl(addr.s_addr);
 168     snprintf(rev, RFC1035_MAXHOSTNAMESZ, "%u.%u.%u.%u.in-addr.arpa.",
 169              i & 255,
 170              (i >> 8) & 255,
 171              (i >> 16) & 255,
 172              (i >> 24) & 255);
 173
 174     return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR);
 175 }
 176
 177 ssize_t
 178
 179 rfc3596BuildPTRQuery6(const struct in6_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query)
 180 {
 181     static char rev[RFC1035_MAXHOSTNAMESZ];
 182     const uint8_t* r = addr.s6_addr;
 183     char* p = rev;
 184     int i; // NP: MUST allow signed for loop termination.
 185
 186     /* work from the raw addr field. anything else may have representation changes. */
 187     /* The sin6_port and sin6_addr members shall be in network byte order. */
 188     for (i = 15; i >= 0; i--, p+=4) {
 189         snprintf(p, 5, "%1x.%1x.", ((r[i]>>4)&0xf), (r[i])&0xf );
 190     }
 191
 192     snprintf(p,10,"ip6.arpa.");
 193
 194     return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR);
 195 }
 196
 197
 198 #if DRIVER
 199
 200 /* driver needs the rfc1035 code _without_ the main() */
 201 #  define main(a,b) rfc1035_main(a,b)
 202 #  include "rfc1035.c"
 203 #  undef main(a,b)
 204
 205 #include <sys/socket.h>
 206
 207 int
 208 main(int argc, char *argv[])
 209 {
 210     char input[512];
 211     char buf[512];
 212     char rbuf[512];
 213     size_t sz = 512;
 214     unsigned short sid, sidb;
 215     int s;
 216     int rl;
 217
 218     struct sockaddr* S;
 219     int var = 1;
 220
 221     if ( argc < 3 || argc > 4) {
 222         fprintf(stderr, "usage: %s [-6|-4] ip port\n", argv[0]);
 223         return 1;
 224     }
 225
 226     setbuf(stdout, NULL);
 227     setbuf(stderr, NULL);
 228
 229     if (argv[var][0] == '-') {
 230         if (argv[var][1] == '4')
 231             prefer = AF_INET;
 232         else if (argv[var][1] == '6')
 233             prefer = AF_INET6;
 234         else {
 235             fprintf(stderr, "usage: %s [-6|-4] ip port\n", argv[0]);
 236             return 1;
 237         }
 238
 239         var++;
 240     }
 241
 242     s = socket(PF_INET, SOCK_DGRAM, 0);
 243
 244     if (s < 0) {
 245         perror("socket");
 246         return 1;
 247     }
 248
 249
 250     memset(&S, '\0', sizeof(S));
 251
 252     if (prefer == 6) {
 253         S = (struct sockaddr *) new sockaddr_in6;
 254         memset(S,0,sizeof(struct sockaddr_in6));
 255
 256         ((struct sockaddr_in6 *)S)->sin6_family = AF_INET6;
 257         ((struct sockaddr_in6 *)S)->sin6_port = htons(atoi(argv[var+1]));
 258
 259         if ( ! inet_pton(AF_INET6, argv[var], &((struct sockaddr_in6 *)S)->sin6_addr.s_addr) )
 260             perror("listen address");
 261         return 1;
 262     }
 263
 264     s = socket(PF_INET6, SOCK_DGRAM, 0);
 265 }
 266 else
 267 {
 268     S = (struct sockaddr *) new sockaddr_in;
 269     memset(S,0,sizeof(struct sockaddr_in));
 270
 271     ((struct sockaddr_in *)S)->sin_family = AF_INET;
 272     ((struct sockaddr_in *)S)->sin_port = htons(atoi(argv[var+1]));
 273
 274     if ( ! inet_pton(AF_INET, argv[var], &((struct sockaddr_in *)S)->sin_addr.s_addr) )
 275         perror("listen address");
 276     return 1;
 277 }
 278 }
 279
 280 while (fgets(input, 512, stdin))
 281 {
 282
 283     struct in6_addr junk6;
 284
 285     struct in_addr junk4;
 286     strtok(input, "\r\n");
 287     memset(buf, '\0', 512);
 288     sz = 512;
 289
 290     if (inet_pton(AF_INET6, input, &junk6)) {
 291         sid = rfc1035BuildPTRQuery6(junk6, buf, &sz);
 292         sidb=0;
 293     } else if (inet_pton(AF_INET, input, &junk4)) {
 294         sid = rfc1035BuildPTRQuery4(junk4, buf, &sz);
 295         sidb=0;
 296     } else {
 297         sid = rfc1035BuildAAAAQuery(input, buf, &sz);
 298         sidb = rfc1035BuildAQuery(input, buf, &sz);
 299     }
 300
 301     sendto(s, buf, sz, 0, S, sizeof(*S));
 302
 303     do {
 304         fd_set R;
 305
 306         struct timeval to;
 307         FD_ZERO(&R);
 308         FD_SET(s, &R);
 309         to.tv_sec = 10;
 310         to.tv_usec = 0;
 311         rl = select(s + 1, &R, NULL, NULL, &to);
 312     } while (0);
 313
 314     if (rl < 1) {
 315         printf("TIMEOUT\n");
 316         continue;
 317     }
 318
 319     memset(rbuf, '\0', 512);
 320     rl = recv(s, rbuf, 512, 0);
 321     {
 322         unsigned short rid = 0;
 323         int i;
 324         int n;
 325         rfc1035_rr *answers = NULL;
 326         n = rfc1035AnswersUnpack(rbuf,
 327                                  rl,
 328                                  &answers,
 329                                  &rid);
 330
 331         if (n < 0) {
 332             printf("ERROR %d\n", rfc1035_errno);
 333         } else if (rid != sid && rid != sidb) {
 334             printf("ERROR, ID mismatch (%#hx, %#hx)\n", sid, rid);
 335             printf("ERROR, ID mismatch (%#hx, %#hx)\n", sidb, rid);
 336         } else {
 337             printf("%d answers\n", n);
 338
 339             for (i = 0; i < n; i++) {
 340                 if (answers[i].type == RFC1035_TYPE_A) {
 341
 342                     struct in_addr a;
 343                     char tmp[16];
 344                     memcpy(&a, answers[i].rdata, 4);
 345                     printf("A\t%d\t%s\n", answers[i].ttl, inet_ntop(AF_INET,&a,tmp,16));
 346                 } else if (answers[i].type == RFC1035_TYPE_AAAA) {
 347
 348                     struct in6_addr a;
 349                     char tmp[INET6_ADDRSTRLEN];
 350                     memcpy(&a, answers[i].rdata, 16);
 351                     printf("AAAA\t%d\t%s\n", answers[i].ttl, inet_ntop(AF_INET6,&a,tmp,sizeof(tmp)));
 352                 } else if (answers[i].type == RFC1035_TYPE_PTR) {
 353                     char ptr[RFC1035_MAXHOSTNAMESZ];
 354                     strncpy(ptr, answers[i].rdata, answers[i].rdlength);
 355                     printf("PTR\t%d\t%s\n", answers[i].ttl, ptr);
 356                 } else if (answers[i].type == RFC1035_TYPE_CNAME) {
 357                     char ptr[RFC1035_MAXHOSTNAMESZ];
 358                     strncpy(ptr, answers[i].rdata, answers[i].rdlength);
 359                     printf("CNAME\t%d\t%s\n", answers[i].ttl, ptr);
 360                 } else {
 361                     fprintf(stderr, "can't print answer type %d\n",
 362                             (int) answers[i].type);
 363                 }
 364             }
 365         }
 366     }
 367 }
 368
 369 return 0;
 370        }
 371
 372 #endif