121374Sdist /* 233734Sbostic * Copyright (c) 1985, 1988 Regents of the University of California. 333734Sbostic * All rights reserved. 433734Sbostic * 5*42625Sbostic * %sccs.include.redist.c% 621374Sdist */ 715662Sralph 826630Sdonn #if defined(LIBC_SCCS) && !defined(lint) 9*42625Sbostic static char sccsid[] = "@(#)gethostnamadr.c 6.41 (Berkeley) 06/01/90"; 1033734Sbostic #endif /* LIBC_SCCS and not lint */ 1121374Sdist 1230468Skjd #include <sys/param.h> 1318505Sralph #include <sys/socket.h> 1418505Sralph #include <netinet/in.h> 1526887Skjd #include <ctype.h> 1618505Sralph #include <netdb.h> 1715662Sralph #include <stdio.h> 1826887Skjd #include <errno.h> 1927034Skjd #include <arpa/inet.h> 2024508Sbloom #include <arpa/nameser.h> 2126894Skjd #include <resolv.h> 2215662Sralph 2315662Sralph #define MAXALIASES 35 2433735Sbostic #define MAXADDRS 35 2515662Sralph 2624687Sbloom static char *h_addr_ptrs[MAXADDRS + 1]; 2724687Sbloom 2824687Sbloom static struct hostent host; 2915662Sralph static char *host_aliases[MAXALIASES]; 3015912Sralph static char hostbuf[BUFSIZ+1]; 3125153Sbloom static struct in_addr host_addr; 3226887Skjd static FILE *hostf = NULL; 3326887Skjd static char hostaddr[MAXADDRS]; 3426887Skjd static char *host_addrs[2]; 3526887Skjd static int stayopen = 0; 3637108Sbostic char *strpbrk(); 3715662Sralph 3832648Skarels #if PACKETSZ > 1024 3933735Sbostic #define MAXPACKET PACKETSZ 4032648Skarels #else 4133735Sbostic #define MAXPACKET 1024 4232648Skarels #endif 4332648Skarels 4425302Skjd typedef union { 4533735Sbostic HEADER hdr; 4633735Sbostic u_char buf[MAXPACKET]; 4725302Skjd } querybuf; 4824509Sbloom 4935765Skarels typedef union { 5025302Skjd long al; 5125302Skjd char ac; 5225302Skjd } align; 5325302Skjd 5425302Skjd 5525484Skjd int h_errno; 5626887Skjd extern errno; 5725484Skjd 5815662Sralph static struct hostent * 5933735Sbostic getanswer(answer, anslen, iquery) 6033735Sbostic querybuf *answer; 6133735Sbostic int anslen; 6233735Sbostic int iquery; 6315662Sralph { 6418505Sralph register HEADER *hp; 6533735Sbostic register u_char *cp; 6618505Sralph register int n; 6733735Sbostic u_char *eom; 6833735Sbostic char *bp, **ap; 6927034Skjd int type, class, buflen, ancount, qdcount; 7027034Skjd int haveanswer, getclass = C_ANY; 7124687Sbloom char **hap; 7215662Sralph 7333735Sbostic eom = answer->buf + anslen; 7418505Sralph /* 7518505Sralph * find first satisfactory answer 7618505Sralph */ 7733735Sbostic hp = &answer->hdr; 7818505Sralph ancount = ntohs(hp->ancount); 7925153Sbloom qdcount = ntohs(hp->qdcount); 8018505Sralph bp = hostbuf; 8118505Sralph buflen = sizeof(hostbuf); 8233735Sbostic cp = answer->buf + sizeof(HEADER); 8325153Sbloom if (qdcount) { 8418505Sralph if (iquery) { 8533735Sbostic if ((n = dn_expand((char *)answer->buf, eom, 8626066Skjd cp, bp, buflen)) < 0) { 8725484Skjd h_errno = NO_RECOVERY; 8833500Skarels return ((struct hostent *) NULL); 8925484Skjd } 9018505Sralph cp += n + QFIXEDSZ; 9118505Sralph host.h_name = bp; 9218505Sralph n = strlen(bp) + 1; 9318505Sralph bp += n; 9418505Sralph buflen -= n; 9518505Sralph } else 9632648Skarels cp += dn_skipname(cp, eom) + QFIXEDSZ; 9725153Sbloom while (--qdcount > 0) 9832648Skarels cp += dn_skipname(cp, eom) + QFIXEDSZ; 9925484Skjd } else if (iquery) { 10025484Skjd if (hp->aa) 10125484Skjd h_errno = HOST_NOT_FOUND; 10225484Skjd else 10325484Skjd h_errno = TRY_AGAIN; 10433500Skarels return ((struct hostent *) NULL); 10525484Skjd } 10624687Sbloom ap = host_aliases; 10739862Skarels *ap = NULL; 10824687Sbloom host.h_aliases = host_aliases; 10924687Sbloom hap = h_addr_ptrs; 11039862Skarels *hap = NULL; 11133600Skarels #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 11224687Sbloom host.h_addr_list = h_addr_ptrs; 11330460Skjd #endif 11424687Sbloom haveanswer = 0; 11518505Sralph while (--ancount >= 0 && cp < eom) { 11633735Sbostic if ((n = dn_expand((char *)answer->buf, eom, cp, bp, buflen)) < 0) 11724687Sbloom break; 11818505Sralph cp += n; 11930440Skjd type = _getshort(cp); 12018505Sralph cp += sizeof(u_short); 12130440Skjd class = _getshort(cp); 12218505Sralph cp += sizeof(u_short) + sizeof(u_long); 12330440Skjd n = _getshort(cp); 12418505Sralph cp += sizeof(u_short); 12518505Sralph if (type == T_CNAME) { 12618505Sralph cp += n; 12718505Sralph if (ap >= &host_aliases[MAXALIASES-1]) 12818505Sralph continue; 12918505Sralph *ap++ = bp; 13018505Sralph n = strlen(bp) + 1; 13118505Sralph bp += n; 13218505Sralph buflen -= n; 13318505Sralph continue; 13418505Sralph } 13533735Sbostic if (iquery && type == T_PTR) { 13633735Sbostic if ((n = dn_expand((char *)answer->buf, eom, 13727034Skjd cp, bp, buflen)) < 0) { 13825153Sbloom cp += n; 13925153Sbloom continue; 14025153Sbloom } 14125153Sbloom cp += n; 14225153Sbloom host.h_name = bp; 14325153Sbloom return(&host); 14425153Sbloom } 14533735Sbostic if (iquery || type != T_A) { 14624733Sbloom #ifdef DEBUG 14718505Sralph if (_res.options & RES_DEBUG) 14818505Sralph printf("unexpected answer type %d, size %d\n", 14918505Sralph type, n); 15024733Sbloom #endif 15124687Sbloom cp += n; 15218505Sralph continue; 15318505Sralph } 15424687Sbloom if (haveanswer) { 15524687Sbloom if (n != host.h_length) { 15624687Sbloom cp += n; 15724687Sbloom continue; 15824687Sbloom } 15924687Sbloom if (class != getclass) { 16024687Sbloom cp += n; 16124687Sbloom continue; 16224687Sbloom } 16324687Sbloom } else { 16424687Sbloom host.h_length = n; 16524687Sbloom getclass = class; 16625386Skjd host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC; 16724687Sbloom if (!iquery) { 16824687Sbloom host.h_name = bp; 16924687Sbloom bp += strlen(bp) + 1; 17024687Sbloom } 17118505Sralph } 17225302Skjd 17331902Skarels bp += sizeof(align) - ((u_long)bp % sizeof(align)); 17425302Skjd 17518505Sralph if (bp + n >= &hostbuf[sizeof(hostbuf)]) { 17624733Sbloom #ifdef DEBUG 17718505Sralph if (_res.options & RES_DEBUG) 17818505Sralph printf("size (%d) too big\n", n); 17924733Sbloom #endif 18024687Sbloom break; 18118505Sralph } 18224687Sbloom bcopy(cp, *hap++ = bp, n); 18324687Sbloom bp +=n; 18424687Sbloom cp += n; 18524687Sbloom haveanswer++; 18624687Sbloom } 18724687Sbloom if (haveanswer) { 18824687Sbloom *ap = NULL; 18933600Skarels #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 19024687Sbloom *hap = NULL; 19131902Skarels #else 19231902Skarels host.h_addr = h_addr_ptrs[0]; 19331902Skarels #endif 19418505Sralph return (&host); 19525484Skjd } else { 19625484Skjd h_errno = TRY_AGAIN; 19733500Skarels return ((struct hostent *) NULL); 19825484Skjd } 19915662Sralph } 20015662Sralph 20115662Sralph struct hostent * 20218505Sralph gethostbyname(name) 20318505Sralph char *name; 20415662Sralph { 20533735Sbostic querybuf buf; 20633735Sbostic register char *cp; 20718505Sralph int n; 20826887Skjd extern struct hostent *_gethtbyname(); 20915662Sralph 21032976Sbostic /* 21132976Sbostic * disallow names consisting only of digits/dots, unless 21232976Sbostic * they end in a dot. 21332976Sbostic */ 21432976Sbostic if (isdigit(name[0])) 21532976Sbostic for (cp = name;; ++cp) { 21632976Sbostic if (!*cp) { 21732976Sbostic if (*--cp == '.') 21832976Sbostic break; 21939710Sbloom /* 22039710Sbloom * All-numeric, no dot at the end. 22139710Sbloom * Fake up a hostent as if we'd actually 22239710Sbloom * done a lookup. What if someone types 22339710Sbloom * 255.255.255.255? The test below will 22439710Sbloom * succeed spuriously... ??? 22539710Sbloom */ 22639710Sbloom if ((host_addr.s_addr = inet_addr(name)) == -1) { 22739710Sbloom h_errno = HOST_NOT_FOUND; 22839710Sbloom return((struct hostent *) NULL); 22939710Sbloom } 23039710Sbloom host.h_name = name; 23139710Sbloom host.h_aliases = host_aliases; 23239710Sbloom host_aliases[0] = NULL; 23339710Sbloom host.h_addrtype = AF_INET; 23439710Sbloom host.h_length = sizeof(u_long); 23539710Sbloom h_addr_ptrs[0] = (char *)&host_addr; 23639710Sbloom h_addr_ptrs[1] = (char *)0; 23739710Sbloom #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 23839710Sbloom host.h_addr_list = h_addr_ptrs; 23939710Sbloom #else 24039710Sbloom host.h_addr = h_addr_ptrs[0]; 24139710Sbloom #endif 24239710Sbloom return (&host); 24332976Sbostic } 24432976Sbostic if (!isdigit(*cp) && *cp != '.') 24532976Sbostic break; 24632976Sbostic } 24731111Skarels 24833735Sbostic if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) { 24924733Sbloom #ifdef DEBUG 25018505Sralph if (_res.options & RES_DEBUG) 25133735Sbostic printf("res_search failed\n"); 25224733Sbloom #endif 25333735Sbostic if (errno == ECONNREFUSED) 25433735Sbostic return (_gethtbyname(name)); 25533735Sbostic else 25633735Sbostic return ((struct hostent *) NULL); 25717761Sserge } 25833735Sbostic return (getanswer(&buf, n, 0)); 25915662Sralph } 26015662Sralph 26115662Sralph struct hostent * 26218505Sralph gethostbyaddr(addr, len, type) 26315662Sralph char *addr; 26418505Sralph int len, type; 26515662Sralph { 26618505Sralph int n; 26725302Skjd querybuf buf; 26825153Sbloom register struct hostent *hp; 26925153Sbloom char qbuf[MAXDNAME]; 27026887Skjd extern struct hostent *_gethtbyaddr(); 27126887Skjd 27218505Sralph if (type != AF_INET) 27333500Skarels return ((struct hostent *) NULL); 27435395Sbostic (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 27525484Skjd ((unsigned)addr[3] & 0xff), 27625484Skjd ((unsigned)addr[2] & 0xff), 27725484Skjd ((unsigned)addr[1] & 0xff), 27825484Skjd ((unsigned)addr[0] & 0xff)); 27933735Sbostic n = res_query(qbuf, C_IN, T_PTR, (char *)&buf, sizeof(buf)); 28018505Sralph if (n < 0) { 28124733Sbloom #ifdef DEBUG 28218505Sralph if (_res.options & RES_DEBUG) 28333735Sbostic printf("res_query failed\n"); 28424733Sbloom #endif 28533735Sbostic if (errno == ECONNREFUSED) 28633990Skarels return (_gethtbyaddr(addr, len, type)); 28733500Skarels return ((struct hostent *) NULL); 28817761Sserge } 28933735Sbostic hp = getanswer(&buf, n, 1); 29026887Skjd if (hp == NULL) 29133500Skarels return ((struct hostent *) NULL); 29225153Sbloom hp->h_addrtype = type; 29325153Sbloom hp->h_length = len; 29425282Sbloom h_addr_ptrs[0] = (char *)&host_addr; 29525153Sbloom h_addr_ptrs[1] = (char *)0; 29625153Sbloom host_addr = *(struct in_addr *)addr; 29739710Sbloom #if BSD < 43 && !defined(h_addr) /* new-style hostent structure */ 29839710Sbloom hp->h_addr = h_addr_ptrs[0]; 29939710Sbloom #endif 30025153Sbloom return(hp); 30115662Sralph } 30225302Skjd 30326887Skjd _sethtent(f) 30426887Skjd int f; 30526887Skjd { 30626887Skjd if (hostf == NULL) 30742266Sbostic hostf = fopen(_PATH_HOSTS, "r" ); 30826887Skjd else 30926887Skjd rewind(hostf); 31026887Skjd stayopen |= f; 31126887Skjd } 31226887Skjd 31326887Skjd _endhtent() 31426887Skjd { 31526887Skjd if (hostf && !stayopen) { 31627034Skjd (void) fclose(hostf); 31726887Skjd hostf = NULL; 31826887Skjd } 31926887Skjd } 32026887Skjd 32126887Skjd struct hostent * 32226887Skjd _gethtent() 32326887Skjd { 32426887Skjd char *p; 32526887Skjd register char *cp, **q; 32626887Skjd 32742266Sbostic if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL) 32826887Skjd return (NULL); 32926887Skjd again: 33033735Sbostic if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL) 33126887Skjd return (NULL); 33226887Skjd if (*p == '#') 33326887Skjd goto again; 33437108Sbostic cp = strpbrk(p, "#\n"); 33526887Skjd if (cp == NULL) 33626887Skjd goto again; 33726887Skjd *cp = '\0'; 33837108Sbostic cp = strpbrk(p, " \t"); 33926887Skjd if (cp == NULL) 34026887Skjd goto again; 34126887Skjd *cp++ = '\0'; 34226887Skjd /* THIS STUFF IS INTERNET SPECIFIC */ 34333600Skarels #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 34426887Skjd host.h_addr_list = host_addrs; 34530460Skjd #endif 34626887Skjd host.h_addr = hostaddr; 34726887Skjd *((u_long *)host.h_addr) = inet_addr(p); 34826887Skjd host.h_length = sizeof (u_long); 34926887Skjd host.h_addrtype = AF_INET; 35026887Skjd while (*cp == ' ' || *cp == '\t') 35126887Skjd cp++; 35226887Skjd host.h_name = cp; 35326887Skjd q = host.h_aliases = host_aliases; 35437108Sbostic cp = strpbrk(cp, " \t"); 35526887Skjd if (cp != NULL) 35626887Skjd *cp++ = '\0'; 35726887Skjd while (cp && *cp) { 35826887Skjd if (*cp == ' ' || *cp == '\t') { 35926887Skjd cp++; 36026887Skjd continue; 36126887Skjd } 36226887Skjd if (q < &host_aliases[MAXALIASES - 1]) 36326887Skjd *q++ = cp; 36437108Sbostic cp = strpbrk(cp, " \t"); 36526887Skjd if (cp != NULL) 36626887Skjd *cp++ = '\0'; 36726887Skjd } 36826887Skjd *q = NULL; 36926887Skjd return (&host); 37026887Skjd } 37126887Skjd 37226887Skjd struct hostent * 37326887Skjd _gethtbyname(name) 37426887Skjd char *name; 37526887Skjd { 37626887Skjd register struct hostent *p; 37726887Skjd register char **cp; 37828307Skarels 37926887Skjd _sethtent(0); 38026887Skjd while (p = _gethtent()) { 38131960Sbostic if (strcasecmp(p->h_name, name) == 0) 38226887Skjd break; 38326887Skjd for (cp = p->h_aliases; *cp != 0; cp++) 38431960Sbostic if (strcasecmp(*cp, name) == 0) 38526887Skjd goto found; 38626887Skjd } 38726887Skjd found: 38826887Skjd _endhtent(); 38926887Skjd return (p); 39026887Skjd } 39126887Skjd 39226887Skjd struct hostent * 39326887Skjd _gethtbyaddr(addr, len, type) 39426887Skjd char *addr; 39526887Skjd int len, type; 39626887Skjd { 39726887Skjd register struct hostent *p; 39826887Skjd 39926887Skjd _sethtent(0); 40026887Skjd while (p = _gethtent()) 40126909Skjd if (p->h_addrtype == type && !bcmp(p->h_addr, addr, len)) 40226887Skjd break; 40326887Skjd _endhtent(); 40426887Skjd return (p); 40526887Skjd } 406