hesiod.c revision 1.5
1 /* $NetBSD: hesiod.c,v 1.5 1999/01/21 12:40:07 mycroft Exp $ */ 2 3 /* This file is part of the Hesiod library. 4 * 5 * Copyright (C) 1988, 1989 by the Massachusetts Institute of Technology 6 * 7 * Export of software employing encryption from the United States of 8 * America is assumed to require a specific license from the United 9 * States Government. It is the responsibility of any person or 10 * organization contemplating export to obtain such a license before 11 * exporting. 12 * 13 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 14 * distribute this software and its documentation for any purpose and 15 * without fee is hereby granted, provided that the above copyright 16 * notice appear in all copies and that both that copyright notice and 17 * this permission notice appear in supporting documentation, and that 18 * the name of M.I.T. not be used in advertising or publicity pertaining 19 * to distribution of the software without specific, written prior 20 * permission. M.I.T. makes no representations about the suitability of 21 * this software for any purpose. It is provided "as is" without express 22 * or implied warranty. 23 */ 24 25 #include <sys/cdefs.h> 26 27 #ifndef lint 28 __IDSTRING(rcsid_hesiod_c, "#Header: /afs/rel-eng.athena.mit.edu/project/release/current/source/athena/athena.lib/hesiod/RCS/hesiod.c,v 1.11 93/06/15 10:26:37 mar Exp #"); 29 __IDSTRING(rcsid_resolve_c, "#Header: /afs/rel-eng.athena.mit.edu/project/release/current/source/athena/athena.lib/hesiod/RCS/resolve.c,v 1.7 93/06/15 10:25:45 mar Exp #"); 30 #endif 31 32 #include <sys/types.h> 33 #include <sys/param.h> 34 #include <netinet/in.h> 35 #include <arpa/nameser.h> 36 37 #include <errno.h> 38 #include <hesiod.h> 39 #include <resolv.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <stringlist.h> 44 #include <unistd.h> 45 46 typedef struct rr { 47 u_int16_t type; /* RR type */ 48 u_int16_t class; /* RR class */ 49 int dlen; /* len of data section */ 50 u_char *data; /* pointer to data */ 51 } rr_t, *rr_p; 52 53 typedef struct nsmsg { 54 int len; /* sizeof(msg) */ 55 int ns_off; /* offset to name server RRs */ 56 int ar_off; /* offset to additional RRs */ 57 int count; /* total number of RRs */ 58 HEADER *hd; /* message header */ 59 rr_t rr; /* vector of (stripped-down) RR descriptors */ 60 } nsmsg_t, *nsmsg_p; 61 62 static int Hes_Errno = HES_ER_UNINIT; 63 char *HesConfigFile = _PATH_HESIOD_CONF; 64 static char Hes_LHS[MAXDNAME + 1]; 65 static char Hes_RHS[MAXDNAME + 1]; 66 static u_char *Hes_eoM; 67 68 #define DEF_RETRANS 4 69 #define DEF_RETRY 3 70 71 static void *_hes_rr_scan __P((u_char *, rr_t *)); 72 static nsmsg_p _hes_res_scan __P((u_char *)); 73 static nsmsg_p _hes_res __P((u_char *, int, int)); 74 int hes_init __P((void)); 75 76 static void * 77 _hes_rr_scan(cp, rr) 78 u_char *cp; 79 rr_t *rr; 80 { 81 int n; 82 83 if ((n = dn_skipname(cp, Hes_eoM)) < 0) { 84 errno = EINVAL; 85 return NULL; 86 } 87 88 cp += n; 89 rr->type = _getshort(cp); 90 cp += sizeof(u_int16_t /*type*/); 91 92 rr->class = _getshort(cp); 93 cp += sizeof(u_int16_t /*class*/) + sizeof(u_int32_t /*ttl*/); 94 95 rr->dlen = (int)_getshort(cp); 96 rr->data = cp + sizeof(u_int16_t /*dlen*/); 97 98 return (rr->data + rr->dlen); 99 } 100 101 102 static nsmsg_p 103 _hes_res_scan(msg) 104 u_char *msg; 105 { 106 static u_char bigmess[sizeof(nsmsg_t) + sizeof(rr_t) * 107 ((PACKETSZ-sizeof(HEADER))/RRFIXEDSZ)]; 108 static u_char datmess[PACKETSZ-sizeof(HEADER)]; 109 u_char *cp; 110 rr_t *rp; 111 HEADER *hp; 112 u_char *data = datmess; 113 int n, n_an, n_ns, n_ar, nrec; 114 nsmsg_t *mess = (nsmsg_t *)(void *)bigmess; 115 116 hp = (HEADER *)(void *)msg; 117 cp = msg + sizeof(HEADER); 118 n_an = ntohs(hp->ancount); 119 n_ns = ntohs(hp->nscount); 120 n_ar = ntohs(hp->arcount); 121 nrec = n_an + n_ns + n_ar; 122 123 mess->len = 0; 124 mess->hd = hp; 125 mess->ns_off = n_an; 126 mess->ar_off = n_an + n_ns; 127 mess->count = nrec; 128 rp = &mess->rr; 129 130 /* skip over questions */ 131 if ((n = ntohs(hp->qdcount)) != 0) { 132 while (--n >= 0) { 133 int i; 134 if ((i = dn_skipname(cp, Hes_eoM)) < 0) 135 return NULL; 136 cp += i + (sizeof(u_int16_t /*type*/) 137 + sizeof(u_int16_t /*class*/)); 138 } 139 } 140 #define GRABDATA \ 141 while (--n >= 0) { \ 142 if ((cp = _hes_rr_scan(cp, rp)) == NULL) \ 143 return NULL; \ 144 (void)strncpy((char *)data, (char *)rp->data, \ 145 (size_t)rp->dlen); \ 146 rp->data = data; \ 147 data += rp->dlen; \ 148 *data++ = '\0'; \ 149 rp++; \ 150 } 151 152 /* scan answers */ 153 if ((n = n_an) != 0) 154 GRABDATA 155 156 /* scan name servers */ 157 if ((n = n_ns) != 0) 158 GRABDATA 159 160 /* scan additional records */ 161 if ((n = n_ar) != 0) 162 GRABDATA 163 164 mess->len = (int)((long)cp - (long)msg); 165 166 return(mess); 167 } 168 169 /* 170 * Resolve name into data records 171 */ 172 173 static nsmsg_p 174 _hes_res(name, class, type) 175 u_char *name; 176 int class, type; 177 { 178 static u_char qbuf[PACKETSZ], abuf[PACKETSZ]; 179 int n; 180 u_int32_t res_options = (u_int32_t)_res.options; 181 int res_retrans = _res.retrans; 182 int res_retry = _res.retry; 183 184 #ifdef DEBUG 185 if (_res.options & RES_DEBUG) 186 printf("_hes_res: class = %d, type = %d\n", class, type); 187 #endif 188 189 if (class < 0 || type < 0) { 190 errno = EINVAL; 191 return((nsmsg_t *)NULL); 192 } 193 194 _res.options |= RES_IGNTC; 195 196 n = res_mkquery(QUERY, (char *)name, class, type, NULL, 0, 197 NULL, qbuf, PACKETSZ); 198 if (n < 0) { 199 errno = EMSGSIZE; 200 return((nsmsg_t *)NULL); 201 } 202 203 _res.retrans = DEF_RETRANS; 204 _res.retry = DEF_RETRY; 205 206 n = res_send(qbuf, n, abuf, PACKETSZ); 207 208 _res.options = res_options; 209 _res.retrans = res_retrans; 210 _res.retry = res_retry; 211 212 if (n < 0) { 213 errno = ECONNREFUSED; 214 return((nsmsg_t *)NULL); 215 } 216 Hes_eoM = abuf+n; 217 218 return(_hes_res_scan(abuf)); 219 } 220 221 int 222 hes_init() 223 { 224 FILE *fp; 225 char *key, *cp, *cpp; 226 char buf[MAXDNAME+7]; 227 228 Hes_Errno = HES_ER_UNINIT; 229 Hes_LHS[0] = '\0'; 230 Hes_RHS[0] = '\0'; 231 if ((fp = fopen(HesConfigFile, "r")) == NULL) { 232 /* use defaults compiled in */ 233 /* no file or no access uses defaults */ 234 /* but poorly formed file returns error */ 235 if (DEF_LHS) strncpy(Hes_LHS, DEF_LHS, MAXDNAME); 236 if (DEF_RHS) strncpy(Hes_RHS, DEF_RHS, MAXDNAME); 237 238 /* if DEF_RHS == "", use getdomainname() */ 239 if (Hes_RHS[0] == '\0') 240 (void)getdomainname(Hes_RHS, MAXDNAME); 241 } else { 242 while(fgets(buf, MAXDNAME+7, fp) != NULL) { 243 cp = buf; 244 if (*cp == '#' || *cp == '\n') 245 continue; 246 while(*cp == ' ' || *cp == '\t') 247 cp++; 248 key = cp; 249 while(*cp != ' ' && *cp != '\t' && *cp != '=') 250 cp++; 251 *cp++ = '\0'; 252 if (strcmp(key, "lhs") == 0) 253 cpp = Hes_LHS; 254 else if (strcmp(key, "rhs") == 0) 255 cpp = Hes_RHS; 256 else 257 continue; 258 while(*cp == ' ' || *cp == '\t' || *cp == '=') 259 cp++; 260 if (*cp != '.' && *cp != '\n') { 261 Hes_Errno = HES_ER_CONFIG; 262 fclose(fp); 263 return(Hes_Errno); 264 } 265 (void) strncpy(cpp, cp, strlen(cp)-1); 266 } 267 fclose(fp); 268 } 269 /* see if the RHS is overridden by environment variable */ 270 if ((cp = getenv("HES_DOMAIN")) != NULL) 271 strncpy(Hes_RHS, cp, MAXDNAME); 272 /* the LHS may be null, the RHS must not be null */ 273 if (Hes_RHS[0] == '\0') 274 Hes_Errno = HES_ER_CONFIG; 275 else 276 Hes_Errno = HES_ER_OK; 277 return(Hes_Errno); 278 } 279 280 char * 281 hes_to_bind(HesiodName, HesiodNameType) 282 char *HesiodName, *HesiodNameType; 283 { 284 static char bindname[MAXDNAME]; 285 char *cp, **cpp, *x; 286 char *RHS; 287 int bni = 0; 288 289 #define STRADDBIND(y) for (x = y; *x; x++, bni++) { \ 290 if (bni >= MAXDNAME) \ 291 return NULL; \ 292 bindname[bni] = *x; \ 293 } 294 295 if (Hes_Errno == HES_ER_UNINIT || Hes_Errno == HES_ER_CONFIG) 296 (void) hes_init(); 297 if (Hes_Errno == HES_ER_CONFIG) 298 return(NULL); 299 if ((cp = strchr(HesiodName,'@')) != NULL) { 300 if (strchr(++cp,'.')) 301 RHS = cp; 302 else 303 if ((cpp = hes_resolve(cp, "rhs-extension")) != NULL) 304 RHS = *cpp; 305 else { 306 Hes_Errno = HES_ER_NOTFOUND; 307 return(NULL); 308 } 309 STRADDBIND(HesiodName); 310 *strchr(bindname,'@') = '\0'; 311 } else { 312 RHS = Hes_RHS; 313 STRADDBIND(HesiodName); 314 } 315 STRADDBIND("."); 316 STRADDBIND(HesiodNameType); 317 if (Hes_LHS && Hes_LHS[0]) { 318 if (Hes_LHS[0] != '.') 319 STRADDBIND("."); 320 STRADDBIND(Hes_LHS); 321 } 322 if (RHS[0] != '.') 323 STRADDBIND("."); 324 STRADDBIND(RHS); 325 if (bni == MAXDNAME) 326 bni--; 327 bindname[bni] = '\0'; 328 return(bindname); 329 } 330 331 /* XXX: convert to resolv directly */ 332 char ** 333 hes_resolve(HesiodName, HesiodNameType) 334 char *HesiodName, *HesiodNameType; 335 { 336 char **retvec; 337 char *cp, *ocp, *dst; 338 int i, n; 339 struct nsmsg *ns; 340 rr_t *rp; 341 StringList *sl; 342 343 sl = sl_init(); 344 345 cp = hes_to_bind(HesiodName, HesiodNameType); 346 if (cp == NULL) 347 return(NULL); 348 errno = 0; 349 ns = _hes_res((u_char *)cp, C_IN, T_TXT); 350 if (errno == ETIMEDOUT || errno == ECONNREFUSED) { 351 Hes_Errno = HES_ER_NET; 352 return(NULL); 353 } 354 if (ns == NULL || ns->ns_off <= 0) { 355 Hes_Errno = HES_ER_NOTFOUND; 356 return(NULL); 357 } 358 for(i = 0, rp = &ns->rr; i < ns->ns_off; rp++, i++) { 359 if (rp->class == C_IN && rp->type == T_TXT) { 360 dst = calloc((size_t)(rp->dlen + 1), sizeof(char)); 361 if (dst == NULL) { 362 sl_free(sl, 1); 363 return NULL; 364 } 365 sl_add(sl, dst); 366 ocp = cp = (char *)rp->data; 367 while (cp < ocp + rp->dlen) { 368 n = (unsigned char) *cp++; 369 (void) memmove(dst, cp, (size_t)n); 370 cp += n; 371 dst += n; 372 } 373 *dst = 0; 374 } 375 } 376 sl_add(sl, NULL); 377 retvec = sl->sl_str; /* XXX: nasty, knows stringlist internals */ 378 free(sl); 379 return(retvec); 380 } 381 382 int 383 hes_error() 384 { 385 return(Hes_Errno); 386 } 387 388 void 389 hes_free(hp) 390 char **hp; 391 { 392 int i; 393 if (!hp) 394 return; 395 for (i = 0; hp[i]; i++) 396 free(hp[i]); 397 free(hp); 398 } 399
Indexes created Tue Sep 23 21:09:50 GMT 2025