lib/libcr/net/res_mkupdate.c

   1 /*
   2  * Copyright (c) 1996 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  *
  17  * $FreeBSD: src/lib/libc/net/res_mkupdate.c,v 1.2.2.1 2001/03/05 10:47:11 obrien Exp $
  18  * $DragonFly: src/lib/libcr/net/Attic/res_mkupdate.c,v 1.2 2003/06/17 04:26:44 dillon Exp $
  19  */
  20
  21 /*
  22  * Based on the Dynamic DNS reference implementation by Viraj Bais
  23  * <viraj_bais@ccm.fm.intel.com>
  24  */
  25
  26 #include <sys/types.h>
  27 #include <sys/param.h>
  28
  29 #include <netinet/in.h>
  30 #include <arpa/nameser.h>
  31 #include <arpa/inet.h>
  32
  33 #include <limits.h>
  34 #include <netdb.h>
  35 #include <resolv.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <unistd.h>
  40 #include <ctype.h>
  41
  42 #include "res_config.h"
  43
  44 static int getnum_str(u_char **, u_char *);
  45 static int getword_str(char *, int, u_char **, u_char *);
  46
  47 #define ShrinkBuffer(x)  if ((buflen -= x) < 0) return (-2);
  48
  49 /*
  50  * Form update packets.
  51  * Returns the size of the resulting packet if no error
  52  * On error,
  53  *      returns -1 if error in reading a word/number in rdata
  54  *                 portion for update packets
  55  *              -2 if length of buffer passed is insufficient
  56  *              -3 if zone section is not the first section in
  57  *                 the linked list, or section order has a problem
  58  *              -4 on a number overflow
  59  *              -5 unknown operation or no records
  60  */
  61 int
  62 res_mkupdate(ns_updrec *rrecp_in, u_char *buf, int buflen) {
  63         ns_updrec *rrecp_start = rrecp_in;
  64         HEADER *hp;
  65         u_char c, *cp, *cp1, *sp1, *sp2, *startp, *endp;
  66         int n, i, j, found, soanum, multiline;
  67         ns_updrec *rrecp, *tmprrecp, *recptr = NULL;
  68         struct in_addr ina;
  69         char buf2[MAXDNAME];
  70         int section, numrrs = 0, counts[ns_s_max];
  71         u_int16_t rtype, rclass;
  72         u_int32_t n1, rttl;
  73         u_char *dnptrs[20], **dpp, **lastdnptr;
  74
  75         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
  76                 h_errno = NETDB_INTERNAL;
  77                 return (-1);
  78         }
  79
  80         /*
  81          * Initialize header fields.
  82          */
  83         if ((buf == NULL) || (buflen < HFIXEDSZ))
  84                 return (-1);
  85         memset(buf, 0, HFIXEDSZ);
  86         hp = (HEADER *) buf;
  87         hp->id = htons(++_res.id);
  88         hp->opcode = ns_o_update;
  89         hp->rcode = NOERROR;
  90         sp1 = buf + 2*INT16SZ;  /* save pointer to zocount */
  91         cp = buf + HFIXEDSZ;
  92         buflen -= HFIXEDSZ;
  93         dpp = dnptrs;
  94         *dpp++ = buf;
  95         *dpp++ = NULL;
  96         lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
  97
  98         if (rrecp_start == NULL)
  99                 return (-5);
 100         else if (rrecp_start->r_section != S_ZONE)
 101                 return (-3);
 102
 103         memset(counts, 0, sizeof counts);
 104         for (rrecp = rrecp_start; rrecp; rrecp = rrecp->r_grpnext) {
 105                 numrrs++;
 106                 section = rrecp->r_section;
 107                 if (section < 0 || section >= ns_s_max)
 108                         return (-1);
 109                 counts[section]++;
 110                 for (i = section + 1; i < ns_s_max; i++)
 111                         if (counts[i])
 112                                 return (-3);
 113                 rtype = rrecp->r_type;
 114                 rclass = rrecp->r_class;
 115                 rttl = rrecp->r_ttl;
 116                 /* overload class and type */
 117                 if (section == S_PREREQ) {
 118                         rttl = 0;
 119                         switch (rrecp->r_opcode) {
 120                         case YXDOMAIN:
 121                                 rclass = C_ANY;
 122                                 rtype = T_ANY;
 123                                 rrecp->r_size = 0;
 124                                 break;
 125                         case NXDOMAIN:
 126                                 rclass = C_NONE;
 127                                 rtype = T_ANY;
 128                                 rrecp->r_size = 0;
 129                                 break;
 130                         case NXRRSET:
 131                                 rclass = C_NONE;
 132                                 rrecp->r_size = 0;
 133                                 break;
 134                         case YXRRSET:
 135                                 if (rrecp->r_size == 0)
 136                                         rclass = C_ANY;
 137                                 break;
 138                         default:
 139                                 fprintf(stderr,
 140                                         "res_mkupdate: incorrect opcode: %d\n",
 141                                         rrecp->r_opcode);
 142                                 fflush(stderr);
 143                                 return (-1);
 144                         }
 145                 } else if (section == S_UPDATE) {
 146                         switch (rrecp->r_opcode) {
 147                         case DELETE:
 148                                 rclass = rrecp->r_size == 0 ? C_ANY : C_NONE;
 149                                 break;
 150                         case ADD:
 151                                 break;
 152                         default:
 153                                 fprintf(stderr,
 154                                         "res_mkupdate: incorrect opcode: %d\n",
 155                                         rrecp->r_opcode);
 156                                 fflush(stderr);
 157                                 return (-1);
 158                         }
 159                 }
 160
 161                 /*
 162                  * XXX  appending default domain to owner name is omitted,
 163                  *      fqdn must be provided
 164                  */
 165                 if ((n = dn_comp(rrecp->r_dname, cp, buflen, dnptrs,
 166                                  lastdnptr)) < 0)
 167                         return (-1);
 168                 cp += n;
 169                 ShrinkBuffer(n + 2*INT16SZ);
 170                 PUTSHORT(rtype, cp);
 171                 PUTSHORT(rclass, cp);
 172                 if (section == S_ZONE) {
 173                         if (numrrs != 1 || rrecp->r_type != T_SOA)
 174                                 return (-3);
 175                         continue;
 176                 }
 177                 ShrinkBuffer(INT32SZ + INT16SZ);
 178                 PUTLONG(rttl, cp);
 179                 sp2 = cp;  /* save pointer to length byte */
 180                 cp += INT16SZ;
 181                 if (rrecp->r_size == 0) {
 182                         if (section == S_UPDATE && rclass != C_ANY)
 183                                 return (-1);
 184                         else {
 185                                 PUTSHORT(0, sp2);
 186                                 continue;
 187                         }
 188                 }
 189                 startp = rrecp->r_data;
 190                 endp = startp + rrecp->r_size - 1;
 191                 /* XXX this should be done centrally. */
 192                 switch (rrecp->r_type) {
 193                 case T_A:
 194                         if (!getword_str(buf2, sizeof buf2, &startp, endp))
 195                                 return (-1);
 196                         if (!inet_aton(buf2, &ina))
 197                                 return (-1);
 198                         n1 = ntohl(ina.s_addr);
 199                         ShrinkBuffer(INT32SZ);
 200                         PUTLONG(n1, cp);
 201                         break;
 202                 case T_CNAME:
 203                 case T_MB:
 204                 case T_MG:
 205                 case T_MR:
 206                 case T_NS:
 207                 case T_PTR:
 208                         if (!getword_str(buf2, sizeof buf2, &startp, endp))
 209                                 return (-1);
 210                         n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
 211                         if (n < 0)
 212                                 return (-1);
 213                         cp += n;
 214                         ShrinkBuffer(n);
 215                         break;
 216                 case T_MINFO:
 217                 case T_SOA:
 218                 case T_RP:
 219                         for (i = 0; i < 2; i++) {
 220                                 if (!getword_str(buf2, sizeof buf2, &startp,
 221                                                  endp))
 222                                 return (-1);
 223                                 n = dn_comp(buf2, cp, buflen,
 224                                             dnptrs, lastdnptr);
 225                                 if (n < 0)
 226                                         return (-1);
 227                                 cp += n;
 228                                 ShrinkBuffer(n);
 229                         }
 230                         if (rrecp->r_type == T_SOA) {
 231                                 ShrinkBuffer(5 * INT32SZ);
 232                                 while (isspace(*startp) || !*startp)
 233                                         startp++;
 234                                 if (*startp == '(') {
 235                                         multiline = 1;
 236                                         startp++;
 237                                 } else
 238                                         multiline = 0;
 239                                 /* serial, refresh, retry, expire, minimum */
 240                                 for (i = 0; i < 5; i++) {
 241                                         soanum = getnum_str(&startp, endp);
 242                                         if (soanum < 0)
 243                                                 return (-1);
 244                                         PUTLONG(soanum, cp);
 245                                 }
 246                                 if (multiline) {
 247                                         while (isspace(*startp) || !*startp)
 248                                                 startp++;
 249                                         if (*startp != ')')
 250                                                 return (-1);
 251                                 }
 252                         }
 253                         break;
 254                 case T_MX:
 255                 case T_AFSDB:
 256                 case T_RT:
 257                         n = getnum_str(&startp, endp);
 258                         if (n < 0)
 259                                 return (-1);
 260                         PUTSHORT(n, cp);
 261                         ShrinkBuffer(INT16SZ);
 262                         if (!getword_str(buf2, sizeof buf2, &startp, endp))
 263                                 return (-1);
 264                         n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
 265                         if (n < 0)
 266                                 return (-1);
 267                         cp += n;
 268                         ShrinkBuffer(n);
 269                         break;
 270                 case T_PX:
 271                         n = getnum_str(&startp, endp);
 272                         if (n < 0)
 273                                 return (-1);
 274                         PUTSHORT(n, cp);
 275                         ShrinkBuffer(INT16SZ);
 276                         for (i = 0; i < 2; i++) {
 277                                 if (!getword_str(buf2, sizeof buf2, &startp,
 278                                                  endp))
 279                                         return (-1);
 280                                 n = dn_comp(buf2, cp, buflen, dnptrs,
 281                                             lastdnptr);
 282                                 if (n < 0)
 283                                         return (-1);
 284                                 cp += n;
 285                                 ShrinkBuffer(n);
 286                         }
 287                         break;
 288                 case T_WKS:
 289                 case T_HINFO:
 290                 case T_TXT:
 291                 case T_X25:
 292                 case T_ISDN:
 293                 case T_NSAP:
 294                 case T_LOC:
 295                         /* XXX - more fine tuning needed here */
 296                         ShrinkBuffer(rrecp->r_size);
 297                         memcpy(cp, rrecp->r_data, rrecp->r_size);
 298                         cp += rrecp->r_size;
 299                         break;
 300                 default:
 301                         return (-1);
 302                 } /*switch*/
 303                 n = (u_int16_t)((cp - sp2) - INT16SZ);
 304                 PUTSHORT(n, sp2);
 305         } /*for*/
 306
 307         hp->qdcount = htons(counts[0]);
 308         hp->ancount = htons(counts[1]);
 309         hp->nscount = htons(counts[2]);
 310         hp->arcount = htons(counts[3]);
 311         return (cp - buf);
 312 }
 313
 314 /*
 315  * Get a whitespace delimited word from a string (not file)
 316  * into buf. modify the start pointer to point after the
 317  * word in the string.
 318  */
 319 static int
 320 getword_str(char *buf, int size, u_char **startpp, u_char *endp) {
 321         char *cp;
 322         int c;
 323
 324         for (cp = buf; *startpp <= endp; ) {
 325                 c = **startpp;
 326                 if (isspace(c) || c == '\0') {
 327                         if (cp != buf) /* trailing whitespace */
 328                                 break;
 329                         else { /* leading whitespace */
 330                                 (*startpp)++;
 331                                 continue;
 332                         }
 333                 }
 334                 (*startpp)++;
 335                 if (cp >= buf+size-1)
 336                         break;
 337                 *cp++ = (u_char)c;
 338         }
 339         *cp = '\0';
 340         return (cp != buf);
 341 }
 342
 343 /*
 344  * Get a whitespace delimited number from a string (not file) into buf
 345  * update the start pointer to point after the number in the string.
 346  */
 347 static int
 348 getnum_str(u_char **startpp, u_char *endp) {
 349         int c, n;
 350         int seendigit = 0;
 351         int seendecimal = 0;
 352         int m = 0;
 353
 354         for (n = 0; *startpp <= endp; ) {
 355                 c = **startpp;
 356                 if (isspace(c) || c == '\0') {
 357                         if (seendigit) /* trailing whitespace */
 358                                 break;
 359                         else { /* leading whitespace */
 360                                 (*startpp)++;
 361                                 continue;
 362                         }
 363                 }
 364                 if (c == ';') {
 365                         while ((*startpp <= endp) &&
 366                                ((c = **startpp) != '\n'))
 367                                         (*startpp)++;
 368                         if (seendigit)
 369                                 break;
 370                         continue;
 371                 }
 372                 if (!isdigit(c)) {
 373                         if (c == ')' && seendigit) {
 374                                 (*startpp)--;
 375                                 break;
 376                         }
 377                         return (-1);
 378                 }
 379                 (*startpp)++;
 380                 n = n * 10 + (c - '0');
 381                 seendigit = 1;
 382         }
 383         return (n + m);
 384 }
 385
 386 /*
 387  * Allocate a resource record buffer & save rr info.
 388  */
 389 ns_updrec *
 390 res_mkupdrec(int section, const char *dname,
 391              u_int class, u_int type, u_long ttl) {
 392         ns_updrec *rrecp = (ns_updrec *)calloc(1, sizeof(ns_updrec));
 393
 394         if (!rrecp || !(rrecp->r_dname = strdup(dname)))
 395                 return (NULL);
 396         rrecp->r_class = class;
 397         rrecp->r_type = type;
 398         rrecp->r_ttl = ttl;
 399         rrecp->r_section = section;
 400         return (rrecp);
 401 }
 402
 403 /*
 404  * Free a resource record buffer created by res_mkupdrec.
 405  */
 406 void
 407 res_freeupdrec(ns_updrec *rrecp) {
 408         /* Note: freeing r_dp is the caller's responsibility. */
 409         if (rrecp->r_dname != NULL)
 410                 free(rrecp->r_dname);
 411         free(rrecp);
 412 }