1 /* 2 * Copyright (c) 1985, 1988 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #if defined(LIBC_SCCS) && !defined(lint) 9 static char sccsid[] = "@(#)gethostnamadr.c 6.41 (Berkeley) 06/01/90"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/param.h> 13 #include <sys/socket.h> 14 #include <netinet/in.h> 15 #include <ctype.h> 16 #include <netdb.h> 17 #include <stdio.h> 18 #include <errno.h> 19 #include <arpa/inet.h> 20 #include <arpa/nameser.h> 21 #include <resolv.h> 22 23 #define MAXALIASES 35 24 #define MAXADDRS 35 25 26 static char *h_addr_ptrs[MAXADDRS + 1]; 27 28 static struct hostent host; 29 static char *host_aliases[MAXALIASES]; 30 static char hostbuf[BUFSIZ+1]; 31 static struct in_addr host_addr; 32 static FILE *hostf = NULL; 33 static char hostaddr[MAXADDRS]; 34 static char *host_addrs[2]; 35 static int stayopen = 0; 36 char *strpbrk(); 37 38 #if PACKETSZ > 1024 39 #define MAXPACKET PACKETSZ 40 #else 41 #define MAXPACKET 1024 42 #endif 43 44 typedef union { 45 HEADER hdr; 46 u_char buf[MAXPACKET]; 47 } querybuf; 48 49 typedef union { 50 long al; 51 char ac; 52 } align; 53 54 55 int h_errno; 56 extern errno; 57 58 static struct hostent * 59 getanswer(answer, anslen, iquery) 60 querybuf *answer; 61 int anslen; 62 int iquery; 63 { 64 register HEADER *hp; 65 register u_char *cp; 66 register int n; 67 u_char *eom; 68 char *bp, **ap; 69 int type, class, buflen, ancount, qdcount; 70 int haveanswer, getclass = C_ANY; 71 char **hap; 72 73 eom = answer->buf + anslen; 74 /* 75 * find first satisfactory answer 76 */ 77 hp = &answer->hdr; 78 ancount = ntohs(hp->ancount); 79 qdcount = ntohs(hp->qdcount); 80 bp = hostbuf; 81 buflen = sizeof(hostbuf); 82 cp = answer->buf + sizeof(HEADER); 83 if (qdcount) { 84 if (iquery) { 85 if ((n = dn_expand((char *)answer->buf, eom, 86 cp, bp, buflen)) < 0) { 87 h_errno = NO_RECOVERY; 88 return ((struct hostent *) NULL); 89 } 90 cp += n + QFIXEDSZ; 91 host.h_name = bp; 92 n = strlen(bp) + 1; 93 bp += n; 94 buflen -= n; 95 } else 96 cp += dn_skipname(cp, eom) + QFIXEDSZ; 97 while (--qdcount > 0) 98 cp += dn_skipname(cp, eom) + QFIXEDSZ; 99 } else if (iquery) { 100 if (hp->aa) 101 h_errno = HOST_NOT_FOUND; 102 else 103 h_errno = TRY_AGAIN; 104 return ((struct hostent *) NULL); 105 } 106 ap = host_aliases; 107 *ap = NULL; 108 host.h_aliases = host_aliases; 109 hap = h_addr_ptrs; 110 *hap = NULL; 111 #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 112 host.h_addr_list = h_addr_ptrs; 113 #endif 114 haveanswer = 0; 115 while (--ancount >= 0 && cp < eom) { 116 if ((n = dn_expand((char *)answer->buf, eom, cp, bp, buflen)) < 0) 117 break; 118 cp += n; 119 type = _getshort(cp); 120 cp += sizeof(u_short); 121 class = _getshort(cp); 122 cp += sizeof(u_short) + sizeof(u_long); 123 n = _getshort(cp); 124 cp += sizeof(u_short); 125 if (type == T_CNAME) { 126 cp += n; 127 if (ap >= &host_aliases[MAXALIASES-1]) 128 continue; 129 *ap++ = bp; 130 n = strlen(bp) + 1; 131 bp += n; 132 buflen -= n; 133 continue; 134 } 135 if (iquery && type == T_PTR) { 136 if ((n = dn_expand((char *)answer->buf, eom, 137 cp, bp, buflen)) < 0) { 138 cp += n; 139 continue; 140 } 141 cp += n; 142 host.h_name = bp; 143 return(&host); 144 } 145 if (iquery || type != T_A) { 146 #ifdef DEBUG 147 if (_res.options & RES_DEBUG) 148 printf("unexpected answer type %d, size %d\n", 149 type, n); 150 #endif 151 cp += n; 152 continue; 153 } 154 if (haveanswer) { 155 if (n != host.h_length) { 156 cp += n; 157 continue; 158 } 159 if (class != getclass) { 160 cp += n; 161 continue; 162 } 163 } else { 164 host.h_length = n; 165 getclass = class; 166 host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC; 167 if (!iquery) { 168 host.h_name = bp; 169 bp += strlen(bp) + 1; 170 } 171 } 172 173 bp += sizeof(align) - ((u_long)bp % sizeof(align)); 174 175 if (bp + n >= &hostbuf[sizeof(hostbuf)]) { 176 #ifdef DEBUG 177 if (_res.options & RES_DEBUG) 178 printf("size (%d) too big\n", n); 179 #endif 180 break; 181 } 182 bcopy(cp, *hap++ = bp, n); 183 bp +=n; 184 cp += n; 185 haveanswer++; 186 } 187 if (haveanswer) { 188 *ap = NULL; 189 #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 190 *hap = NULL; 191 #else 192 host.h_addr = h_addr_ptrs[0]; 193 #endif 194 return (&host); 195 } else { 196 h_errno = TRY_AGAIN; 197 return ((struct hostent *) NULL); 198 } 199 } 200 201 struct hostent * 202 gethostbyname(name) 203 char *name; 204 { 205 querybuf buf; 206 register char *cp; 207 int n; 208 extern struct hostent *_gethtbyname(); 209 210 /* 211 * disallow names consisting only of digits/dots, unless 212 * they end in a dot. 213 */ 214 if (isdigit(name[0])) 215 for (cp = name;; ++cp) { 216 if (!*cp) { 217 if (*--cp == '.') 218 break; 219 /* 220 * All-numeric, no dot at the end. 221 * Fake up a hostent as if we'd actually 222 * done a lookup. What if someone types 223 * 255.255.255.255? The test below will 224 * succeed spuriously... ??? 225 */ 226 if ((host_addr.s_addr = inet_addr(name)) == -1) { 227 h_errno = HOST_NOT_FOUND; 228 return((struct hostent *) NULL); 229 } 230 host.h_name = name; 231 host.h_aliases = host_aliases; 232 host_aliases[0] = NULL; 233 host.h_addrtype = AF_INET; 234 host.h_length = sizeof(u_long); 235 h_addr_ptrs[0] = (char *)&host_addr; 236 h_addr_ptrs[1] = (char *)0; 237 #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 238 host.h_addr_list = h_addr_ptrs; 239 #else 240 host.h_addr = h_addr_ptrs[0]; 241 #endif 242 return (&host); 243 } 244 if (!isdigit(*cp) && *cp != '.') 245 break; 246 } 247 248 if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) { 249 #ifdef DEBUG 250 if (_res.options & RES_DEBUG) 251 printf("res_search failed\n"); 252 #endif 253 if (errno == ECONNREFUSED) 254 return (_gethtbyname(name)); 255 else 256 return ((struct hostent *) NULL); 257 } 258 return (getanswer(&buf, n, 0)); 259 } 260 261 struct hostent * 262 gethostbyaddr(addr, len, type) 263 char *addr; 264 int len, type; 265 { 266 int n; 267 querybuf buf; 268 register struct hostent *hp; 269 char qbuf[MAXDNAME]; 270 extern struct hostent *_gethtbyaddr(); 271 272 if (type != AF_INET) 273 return ((struct hostent *) NULL); 274 (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 275 ((unsigned)addr[3] & 0xff), 276 ((unsigned)addr[2] & 0xff), 277 ((unsigned)addr[1] & 0xff), 278 ((unsigned)addr[0] & 0xff)); 279 n = res_query(qbuf, C_IN, T_PTR, (char *)&buf, sizeof(buf)); 280 if (n < 0) { 281 #ifdef DEBUG 282 if (_res.options & RES_DEBUG) 283 printf("res_query failed\n"); 284 #endif 285 if (errno == ECONNREFUSED) 286 return (_gethtbyaddr(addr, len, type)); 287 return ((struct hostent *) NULL); 288 } 289 hp = getanswer(&buf, n, 1); 290 if (hp == NULL) 291 return ((struct hostent *) NULL); 292 hp->h_addrtype = type; 293 hp->h_length = len; 294 h_addr_ptrs[0] = (char *)&host_addr; 295 h_addr_ptrs[1] = (char *)0; 296 host_addr = *(struct in_addr *)addr; 297 #if BSD < 43 && !defined(h_addr) /* new-style hostent structure */ 298 hp->h_addr = h_addr_ptrs[0]; 299 #endif 300 return(hp); 301 } 302 303 _sethtent(f) 304 int f; 305 { 306 if (hostf == NULL) 307 hostf = fopen(_PATH_HOSTS, "r" ); 308 else 309 rewind(hostf); 310 stayopen |= f; 311 } 312 313 _endhtent() 314 { 315 if (hostf && !stayopen) { 316 (void) fclose(hostf); 317 hostf = NULL; 318 } 319 } 320 321 struct hostent * 322 _gethtent() 323 { 324 char *p; 325 register char *cp, **q; 326 327 if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL) 328 return (NULL); 329 again: 330 if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL) 331 return (NULL); 332 if (*p == '#') 333 goto again; 334 cp = strpbrk(p, "#\n"); 335 if (cp == NULL) 336 goto again; 337 *cp = '\0'; 338 cp = strpbrk(p, " \t"); 339 if (cp == NULL) 340 goto again; 341 *cp++ = '\0'; 342 /* THIS STUFF IS INTERNET SPECIFIC */ 343 #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 344 host.h_addr_list = host_addrs; 345 #endif 346 host.h_addr = hostaddr; 347 *((u_long *)host.h_addr) = inet_addr(p); 348 host.h_length = sizeof (u_long); 349 host.h_addrtype = AF_INET; 350 while (*cp == ' ' || *cp == '\t') 351 cp++; 352 host.h_name = cp; 353 q = host.h_aliases = host_aliases; 354 cp = strpbrk(cp, " \t"); 355 if (cp != NULL) 356 *cp++ = '\0'; 357 while (cp && *cp) { 358 if (*cp == ' ' || *cp == '\t') { 359 cp++; 360 continue; 361 } 362 if (q < &host_aliases[MAXALIASES - 1]) 363 *q++ = cp; 364 cp = strpbrk(cp, " \t"); 365 if (cp != NULL) 366 *cp++ = '\0'; 367 } 368 *q = NULL; 369 return (&host); 370 } 371 372 struct hostent * 373 _gethtbyname(name) 374 char *name; 375 { 376 register struct hostent *p; 377 register char **cp; 378 379 _sethtent(0); 380 while (p = _gethtent()) { 381 if (strcasecmp(p->h_name, name) == 0) 382 break; 383 for (cp = p->h_aliases; *cp != 0; cp++) 384 if (strcasecmp(*cp, name) == 0) 385 goto found; 386 } 387 found: 388 _endhtent(); 389 return (p); 390 } 391 392 struct hostent * 393 _gethtbyaddr(addr, len, type) 394 char *addr; 395 int len, type; 396 { 397 register struct hostent *p; 398 399 _sethtent(0); 400 while (p = _gethtent()) 401 if (p->h_addrtype == type && !bcmp(p->h_addr, addr, len)) 402 break; 403 _endhtent(); 404 return (p); 405 } 406