lib/libc/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/libc/net/res_mkupdate.c,v 1.3 2005/11/13 02:04:47 swildner 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 {
  64         ns_updrec *rrecp_start = rrecp_in;
  65         HEADER *hp;
  66         u_char *cp, *sp1, *sp2, *startp, *endp;
  67         int n, i, soanum, multiline;
  68         ns_updrec *rrecp;
  69         struct in_addr ina;
  70         char buf2[MAXDNAME];
  71         int section, numrrs = 0, counts[ns_s_max];
  72         u_int16_t rtype, rclass;
  73         u_int32_t n1, rttl;
  74         u_char *dnptrs[20], **dpp, **lastdnptr;
  75
  76         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
  77                 h_errno = NETDB_INTERNAL;
  78                 return (-1);
  79         }
  80
  81         /*
  82          * Initialize header fields.
  83          */
  84         if ((buf == NULL) || (buflen < HFIXEDSZ))
  85                 return (-1);
  86         memset(buf, 0, HFIXEDSZ);
  87         hp = (HEADER *) buf;
  88         hp->id = htons(++_res.id);
  89         hp->opcode = ns_o_update;
  90         hp->rcode = NOERROR;
  91         sp1 = buf + 2*INT16SZ;  /* save pointer to zocount */
  92         cp = buf + HFIXEDSZ;
  93         buflen -= HFIXEDSZ;
  94         dpp = dnptrs;
  95         *dpp++ = buf;
  96         *dpp++ = NULL;
  97         lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
  98
  99         if (rrecp_start == NULL)
 100                 return (-5);
 101         else if (rrecp_start->r_section != S_ZONE)
 102                 return (-3);
 103
 104         memset(counts, 0, sizeof counts);
 105         for (rrecp = rrecp_start; rrecp; rrecp = rrecp->r_grpnext) {
 106                 numrrs++;
 107                 section = rrecp->r_section;
 108                 if (section < 0 || section >= ns_s_max)
 109                         return (-1);
 110                 counts[section]++;
 111                 for (i = section + 1; i < ns_s_max; i++)
 112                         if (counts[i])
 113                                 return (-3);
 114                 rtype = rrecp->r_type;
 115                 rclass = rrecp->r_class;
 116                 rttl = rrecp->r_ttl;
 117                 /* overload class and type */
 118                 if (section == S_PREREQ) {
 119                         rttl = 0;
 120                         switch (rrecp->r_opcode) {
 121                         case YXDOMAIN:
 122                                 rclass = C_ANY;
 123                                 rtype = T_ANY;
 124                                 rrecp->r_size = 0;
 125                                 break;
 126                         case NXDOMAIN:
 127                                 rclass = C_NONE;
 128                                 rtype = T_ANY;
 129                                 rrecp->r_size = 0;
 130                                 break;
 131                         case NXRRSET:
 132                                 rclass = C_NONE;
 133                                 rrecp->r_size = 0;
 134                                 break;
 135                         case YXRRSET:
 136                                 if (rrecp->r_size == 0)
 137                                         rclass = C_ANY;
 138                                 break;
 139                         default:
 140                                 fprintf(stderr,
 141                                         "res_mkupdate: incorrect opcode: %d\n",
 142                                         rrecp->r_opcode);
 143                                 fflush(stderr);
 144                                 return (-1);
 145                         }
 146                 } else if (section == S_UPDATE) {
 147                         switch (rrecp->r_opcode) {
 148                         case DELETE:
 149                                 rclass = rrecp->r_size == 0 ? C_ANY : C_NONE;
 150                                 break;
 151                         case ADD:
 152                                 break;
 153                         default:
 154                                 fprintf(stderr,
 155                                         "res_mkupdate: incorrect opcode: %d\n",
 156                                         rrecp->r_opcode);
 157                                 fflush(stderr);
 158                                 return (-1);
 159                         }
 160                 }
 161
 162                 /*
 163                  * XXX  appending default domain to owner name is omitted,
 164                  *      fqdn must be provided
 165                  */
 166                 if ((n = dn_comp(rrecp->r_dname, cp, buflen, dnptrs,
 167                                  lastdnptr)) < 0)
 168                         return (-1);
 169                 cp += n;
 170                 ShrinkBuffer(n + 2*INT16SZ);
 171                 PUTSHORT(rtype, cp);
 172                 PUTSHORT(rclass, cp);
 173                 if (section == S_ZONE) {
 174                         if (numrrs != 1 || rrecp->r_type != T_SOA)
 175                                 return (-3);
 176                         continue;
 177                 }
 178                 ShrinkBuffer(INT32SZ + INT16SZ);
 179                 PUTLONG(rttl, cp);
 180                 sp2 = cp;  /* save pointer to length byte */
 181                 cp += INT16SZ;
 182                 if (rrecp->r_size == 0) {
 183                         if (section == S_UPDATE && rclass != C_ANY)
 184                                 return (-1);
 185                         else {
 186                                 PUTSHORT(0, sp2);
 187                                 continue;
 188                         }
 189                 }
 190                 startp = rrecp->r_data;
 191                 endp = startp + rrecp->r_size - 1;
 192                 /* XXX this should be done centrally. */
 193                 switch (rrecp->r_type) {
 194                 case T_A:
 195                         if (!getword_str(buf2, sizeof buf2, &startp, endp))
 196                                 return (-1);
 197                         if (!inet_aton(buf2, &ina))
 198                                 return (-1);
 199                         n1 = ntohl(ina.s_addr);
 200                         ShrinkBuffer(INT32SZ);
 201                         PUTLONG(n1, cp);
 202                         break;
 203                 case T_CNAME:
 204                 case T_MB:
 205                 case T_MG:
 206                 case T_MR:
 207                 case T_NS:
 208                 case T_PTR:
 209                         if (!getword_str(buf2, sizeof buf2, &startp, endp))
 210                                 return (-1);
 211                         n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
 212                         if (n < 0)
 213                                 return (-1);
 214                         cp += n;
 215                         ShrinkBuffer(n);
 216                         break;
 217                 case T_MINFO:
 218                 case T_SOA:
 219                 case T_RP:
 220                         for (i = 0; i < 2; i++) {
 221                                 if (!getword_str(buf2, sizeof buf2, &startp,
 222                                                  endp))
 223                                 return (-1);
 224                                 n = dn_comp(buf2, cp, buflen,
 225                                             dnptrs, lastdnptr);
 226                                 if (n < 0)
 227                                         return (-1);
 228                                 cp += n;
 229                                 ShrinkBuffer(n);
 230                         }
 231                         if (rrecp->r_type == T_SOA) {
 232                                 ShrinkBuffer(5 * INT32SZ);
 233                                 while (isspace(*startp) || !*startp)
 234                                         startp++;
 235                                 if (*startp == '(') {
 236                                         multiline = 1;
 237                                         startp++;
 238                                 } else
 239                                         multiline = 0;
 240                                 /* serial, refresh, retry, expire, minimum */
 241                                 for (i = 0; i < 5; i++) {
 242                                         soanum = getnum_str(&startp, endp);
 243                                         if (soanum < 0)
 244                                                 return (-1);
 245                                         PUTLONG(soanum, cp);
 246                                 }
 247                                 if (multiline) {
 248                                         while (isspace(*startp) || !*startp)
 249                                                 startp++;
 250                                         if (*startp != ')')
 251                                                 return (-1);
 252                                 }
 253                         }
 254                         break;
 255                 case T_MX:
 256                 case T_AFSDB:
 257                 case T_RT:
 258                         n = getnum_str(&startp, endp);
 259                         if (n < 0)
 260                                 return (-1);
 261                         PUTSHORT(n, cp);
 262                         ShrinkBuffer(INT16SZ);
 263                         if (!getword_str(buf2, sizeof buf2, &startp, endp))
 264                                 return (-1);
 265                         n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
 266                         if (n < 0)
 267                                 return (-1);
 268                         cp += n;
 269                         ShrinkBuffer(n);
 270                         break;
 271                 case T_PX:
 272                         n = getnum_str(&startp, endp);
 273                         if (n < 0)
 274                                 return (-1);
 275                         PUTSHORT(n, cp);
 276                         ShrinkBuffer(INT16SZ);
 277                         for (i = 0; i < 2; i++) {
 278                                 if (!getword_str(buf2, sizeof buf2, &startp,
 279                                                  endp))
 280                                         return (-1);
 281                                 n = dn_comp(buf2, cp, buflen, dnptrs,
 282                                             lastdnptr);
 283                                 if (n < 0)
 284                                         return (-1);
 285                                 cp += n;
 286                                 ShrinkBuffer(n);
 287                         }
 288                         break;
 289                 case T_WKS:
 290                 case T_HINFO:
 291                 case T_TXT:
 292                 case T_X25:
 293                 case T_ISDN:
 294                 case T_NSAP:
 295                 case T_LOC:
 296                         /* XXX - more fine tuning needed here */
 297                         ShrinkBuffer(rrecp->r_size);
 298                         memcpy(cp, rrecp->r_data, rrecp->r_size);
 299                         cp += rrecp->r_size;
 300                         break;
 301                 default:
 302                         return (-1);
 303                 } /*switch*/
 304                 n = (u_int16_t)((cp - sp2) - INT16SZ);
 305                 PUTSHORT(n, sp2);
 306         } /*for*/
 307
 308         hp->qdcount = htons(counts[0]);
 309         hp->ancount = htons(counts[1]);
 310         hp->nscount = htons(counts[2]);
 311         hp->arcount = htons(counts[3]);
 312         return (cp - buf);
 313 }
 314
 315 /*
 316  * Get a whitespace delimited word from a string (not file)
 317  * into buf. modify the start pointer to point after the
 318  * word in the string.
 319  */
 320 static int
 321 getword_str(char *buf, int size, u_char **startpp, u_char *endp)
 322 {
 323         char *cp;
 324         int c;
 325
 326         for (cp = buf; *startpp <= endp; ) {
 327                 c = **startpp;
 328                 if (isspace(c) || c == '\0') {
 329                         if (cp != buf) /* trailing whitespace */
 330                                 break;
 331                         else { /* leading whitespace */
 332                                 (*startpp)++;
 333                                 continue;
 334                         }
 335                 }
 336                 (*startpp)++;
 337                 if (cp >= buf+size-1)
 338                         break;
 339                 *cp++ = (u_char)c;
 340         }
 341         *cp = '\0';
 342         return (cp != buf);
 343 }
 344
 345 /*
 346  * Get a whitespace delimited number from a string (not file) into buf
 347  * update the start pointer to point after the number in the string.
 348  */
 349 static int
 350 getnum_str(u_char **startpp, u_char *endp)
 351 {
 352         int c, n;
 353         int seendigit = 0;
 354         int m = 0;
 355
 356         for (n = 0; *startpp <= endp; ) {
 357                 c = **startpp;
 358                 if (isspace(c) || c == '\0') {
 359                         if (seendigit) /* trailing whitespace */
 360                                 break;
 361                         else { /* leading whitespace */
 362                                 (*startpp)++;
 363                                 continue;
 364                         }
 365                 }
 366                 if (c == ';') {
 367                         while ((*startpp <= endp) &&
 368                                ((c = **startpp) != '\n'))
 369                                         (*startpp)++;
 370                         if (seendigit)
 371                                 break;
 372                         continue;
 373                 }
 374                 if (!isdigit(c)) {
 375                         if (c == ')' && seendigit) {
 376                                 (*startpp)--;
 377                                 break;
 378                         }
 379                         return (-1);
 380                 }
 381                 (*startpp)++;
 382                 n = n * 10 + (c - '0');
 383                 seendigit = 1;
 384         }
 385         return (n + m);
 386 }
 387
 388 /*
 389  * Allocate a resource record buffer & save rr info.
 390  */
 391 ns_updrec *
 392 res_mkupdrec(int section, const char *dname,
 393              u_int class, u_int type, u_long ttl)
 394 {
 395         ns_updrec *rrecp = (ns_updrec *)calloc(1, sizeof(ns_updrec));
 396
 397         if (!rrecp || !(rrecp->r_dname = strdup(dname)))
 398                 return (NULL);
 399         rrecp->r_class = class;
 400         rrecp->r_type = type;
 401         rrecp->r_ttl = ttl;
 402         rrecp->r_section = section;
 403         return (rrecp);
 404 }
 405
 406 /*
 407  * Free a resource record buffer created by res_mkupdrec.
 408  */
 409 void
 410 res_freeupdrec(ns_updrec *rrecp)
 411 {
 412         /* Note: freeing r_dp is the caller's responsibility. */
 413         if (rrecp->r_dname != NULL)
 414                 free(rrecp->r_dname);
 415         free(rrecp);
 416 }