lib/rfc3596.c

   1 /*
   2  * Low level DNS protocol routines
   3  * AUTHOR: Amos Jeffries, Rafael Martinez Torres
   4  *
   5  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   6  * ----------------------------------------------------------
   7  *
   8  *  Squid is the result of efforts by numerous individuals from
   9  *  the Internet community; see the CONTRIBUTORS file for full
  10  *  details.   Many organizations have provided support for Squid's
  11  *  development; see the SPONSORS file for full details.  Squid is
  12  *  Copyrighted (C) 2001 by the Regents of the University of
  13  *  California; see the COPYRIGHT file for full details.  Squid
  14  *  incorporates software developed and/or copyrighted by other
  15  *  sources; see the CREDITS file for full details.
  16  *
  17  *  This code is copyright (C) 2007 by Treehouse Networks Ltd of
  18  *  New Zealand. It is published and Lisenced as an extension of
  19  *  squid under the same conditions as the main squid application.
  20  *
  21  *  This program is free software; you can redistribute it and/or modify
  22  *  it under the terms of the GNU General Public License as published by
  23  *  the Free Software Foundation; either version 2 of the License, or
  24  *  (at your option) any later version.
  25  *
  26  *  This program is distributed in the hope that it will be useful,
  27  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  *  GNU General Public License for more details.
  30  *
  31  *  You should have received a copy of the GNU General Public License
  32  *  along with this program; if not, write to the Free Software
  33  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  34  *
  35  */
  36
  37 /*
  38  * KNOWN BUGS:
  39  *
  40  * UDP replies with TC set should be retried via TCP
  41  */
  42
  43 /**
  44  * April 2007
  45  *
  46  * Provides RFC3596 functions to handle purely IPv6 DNS.
  47  * Adds AAAA and IPv6 PTR records.
  48  * Other IPv6 records are not mentioned by this RFC.
  49  *
  50  * IPv4 equivalents are taken care of by the RFC1035 library.
  51  * Where one protocol lookup must be followed by another, the caller
  52  * is resposible for the order and handling of the lookups.
  53  *
  54  */
  55
  56 #include "squid.h"
  57 #include "compat/inet_pton.h"
  58 #include "util.h"
  59
  60 #if HAVE_STDIO_H
  61 #include <stdio.h>
  62 #endif
  63 #if HAVE_UNISTD_H
  64 #include <unistd.h>
  65 #endif
  66 #if HAVE_MEMORY_H
  67 #include <memory.h>
  68 #endif
  69 #if HAVE_ASSERT_H
  70 #include <assert.h>
  71 #endif
  72 #if HAVE_NETINET_IN_H
  73 #include <netinet/in.h>
  74 #endif
  75 #if HAVE_STRINGS_H
  76 #include <strings.h>
  77 #endif
  78
  79 #include "rfc3596.h"
  80 #include "rfc2671.h"
  81
  82 #ifndef SQUID_RFC1035_H
  83 #error RFC3596 Library depends on RFC1035
  84 #endif
  85
  86 /**
  87  * Builds a message buffer with a QUESTION to lookup records
  88  * for a hostname.  Caller must allocate 'buf' which should
  89  * probably be at least 512 octets.  The 'szp' initially
  90  * specifies the size of the buffer, on return it contains
  91  * the size of the message (i.e. how much to write).
  92  * Returns the size of the query
  93  */
  94 ssize_t
  95 rfc3596BuildHostQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, int qtype, ssize_t edns_sz)
  96 {
  97     static rfc1035_message h;
  98     size_t offset = 0;
  99     memset(&h, '\0', sizeof(h));
 100     h.id = qid;
 101     h.qr = 0;
 102     h.rd = 1;
 103     h.opcode = 0;               /* QUERY */
 104     h.qdcount = (unsigned int) 1;
 105     h.arcount = (edns_sz > 0 ? 1 : 0);
 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     if (edns_sz > 0)
 113         offset += rfc2671RROptPack(buf + offset, sz - offset, edns_sz);
 114
 115     if (query) {
 116         query->qtype = qtype;
 117         query->qclass = RFC1035_CLASS_IN;
 118         xstrncpy(query->name, hostname, sizeof(query->name));
 119     }
 120
 121     assert(offset <= sz);
 122     return offset;
 123 }
 124
 125 /**
 126  * Builds a message buffer with a QUESTION to lookup A records
 127  * for a hostname.  Caller must allocate 'buf' which should
 128  * probably be at least 512 octets.  The 'szp' initially
 129  * specifies the size of the buffer, on return it contains
 130  * the size of the message (i.e. how much to write).
 131  * \return the size of the query
 132  */
 133 ssize_t
 134 rfc3596BuildAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz)
 135 {
 136     return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_A, edns_sz);
 137 }
 138
 139 /**
 140  * Builds a message buffer with a QUESTION to lookup AAAA records
 141  * for a hostname.  Caller must allocate 'buf' which should
 142  * probably be at least 512 octets.  The 'szp' initially
 143  * specifies the size of the buffer, on return it contains
 144  * the size of the message (i.e. how much to write).
 145  * \return the size of the query
 146  */
 147 ssize_t
 148 rfc3596BuildAAAAQuery(const char *hostname, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz)
 149 {
 150     return rfc3596BuildHostQuery(hostname, buf, sz, qid, query, RFC1035_TYPE_AAAA, edns_sz);
 151 }
 152
 153 /**
 154  * Builds a message buffer with a QUESTION to lookup PTR records
 155  * for an address.  Caller must allocate 'buf' which should
 156  * probably be at least 512 octets.  The 'szp' initially
 157  * specifies the size of the buffer, on return it contains
 158  * the size of the message (i.e. how much to write).
 159  * \return the size of the query
 160  */
 161 ssize_t
 162 rfc3596BuildPTRQuery4(const struct in_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz)
 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, edns_sz);
 175 }
 176
 177 ssize_t
 178 rfc3596BuildPTRQuery6(const struct in6_addr addr, char *buf, size_t sz, unsigned short qid, rfc1035_query * query, ssize_t edns_sz)
 179 {
 180     static char rev[RFC1035_MAXHOSTNAMESZ];
 181     const uint8_t* r = addr.s6_addr;
 182     char* p = rev;
 183     int i; /* NP: MUST allow signed for loop termination. */
 184
 185     /* work from the raw addr field. anything else may have representation changes. */
 186     /* The sin6_port and sin6_addr members shall be in network byte order. */
 187     for (i = 15; i >= 0; i--, p+=4) {
 188         snprintf(p, 5, "%1x.%1x.", ((r[i])&0xf), (r[i]>>4)&0xf );
 189     }
 190
 191     snprintf(p,10,"ip6.arpa.");
 192
 193     return rfc3596BuildHostQuery(rev, buf, sz, qid, query, RFC1035_TYPE_PTR, edns_sz);
 194 }
 195
 196 #if DRIVER
 197
 198 /* driver needs the rfc1035 code _without_ the main() */
 199 #  define main(a,b) rfc1035_main(a,b)
 200 #  include "rfc1035.c"
 201 #  undef main(a,b)
 202
 203 #include <sys/socket.h>
 204
 205 int
 206 main(int argc, char *argv[])
 207 {
 208 #define PACKET_BUFSZ            1024
 209     char input[PACKET_BUFSZ];
 210     char buf[PACKET_BUFSZ];
 211     char rbuf[PACKET_BUFSZ];
 212     size_t sz = PACKET_BUFSZ;
 213     unsigned short sid, sidb;
 214     int s;
 215     int rl;
 216     ssize_t edns_max = -1;
 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 if (argv[var][1] == 'E')
 235             edns_max = atoi(argv[var++]);
 236         else {
 237             fprintf(stderr, "usage: %s [-6|-4] [-E packet-size] ip port\n", argv[0]);
 238             fprintf(stderr, "  EDNS packets my be up to %d\n", PACKET_BUFSZ);
 239             return 1;
 240         }
 241
 242         var++;
 243     }
 244
 245     s = socket(PF_INET, SOCK_DGRAM, 0);
 246
 247     if (s < 0) {
 248         perror("socket");
 249         return 1;
 250     }
 251
 252     memset(&S, '\0', sizeof(S));
 253
 254     if (prefer == 6) {
 255         S = (struct sockaddr *) new sockaddr_in6;
 256         memset(S,0,sizeof(struct sockaddr_in6));
 257
 258         ((struct sockaddr_in6 *)S)->sin6_family = AF_INET6;
 259         ((struct sockaddr_in6 *)S)->sin6_port = htons(atoi(argv[var+1]));
 260
 261         if ( ! inet_pton(AF_INET6, argv[var], &((struct sockaddr_in6 *)S)->sin6_addr.s_addr) ) {
 262             perror("listen address");
 263             return 1;
 264         }
 265
 266         s = socket(PF_INET6, SOCK_DGRAM, 0);
 267     } else {
 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, PACKET_BUFSZ, stdin))
 281 {
 282
 283     struct in6_addr junk6;
 284
 285     struct in_addr junk4;
 286     strtok(input, "\r\n");
 287     memset(buf, '\0', PACKET_BUFSZ);
 288     sz = PACKET_BUFSZ;
 289
 290     if (inet_pton(AF_INET6, input, &junk6)) {
 291         sid = rfc1035BuildPTRQuery6(junk6, buf, &sz, edns_max);
 292         sidb=0;
 293     } else if (inet_pton(AF_INET, input, &junk4)) {
 294         sid = rfc1035BuildPTRQuery4(junk4, buf, &sz, edns_max);
 295         sidb=0;
 296     } else {
 297         sid = rfc1035BuildAAAAQuery(input, buf, &sz, edns_max);
 298         sidb = rfc1035BuildAQuery(input, buf, &sz, edns_max);
 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', PACKET_BUFSZ);
 320     rl = recv(s, rbuf, PACKET_BUFSZ, 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", -n);
 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