/* * Copyright (c) 1985, 1988 Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint) /*static char *sccsid = "from: @(#)gethostnamadr.c 6.45 (Berkeley) 2/24/91";*/ static char *rcsid = "$Id: gethostnamadr.c,v 1.4 1994/01/28 03:10:25 deraadt Exp $"; #endif /* LIBC_SCCS and not lint */ #include #include #include #include #include #include #include #include #include #include #include #ifdef YP #include #include #include #endif #define MAXALIASES 35 #define MAXADDRS 35 static char *h_addr_ptrs[MAXADDRS + 1]; #ifdef YP static char *__ypdomain; #endif static struct hostent host; static char *host_aliases[MAXALIASES]; static char hostbuf[BUFSIZ+1]; static struct in_addr host_addr; static FILE *hostf = NULL; static u_long hostaddr[MAXADDRS]; static char *host_addrs[2]; static int stayopen = 0; char *strpbrk(); #if PACKETSZ > 1024 #define MAXPACKET PACKETSZ #else #define MAXPACKET 1024 #endif typedef union { HEADER hdr; u_char buf[MAXPACKET]; } querybuf; typedef union { long al; char ac; } align; int h_errno; static struct hostent * getanswer(answer, anslen, iquery) querybuf *answer; int anslen; int iquery; { register HEADER *hp; register u_char *cp; register int n; u_char *eom; char *bp, **ap; int type, class, buflen, ancount, qdcount; int haveanswer, getclass = C_ANY; char **hap; eom = answer->buf + anslen; /* * find first satisfactory answer */ hp = &answer->hdr; ancount = ntohs(hp->ancount); qdcount = ntohs(hp->qdcount); bp = hostbuf; buflen = sizeof(hostbuf); cp = answer->buf + sizeof(HEADER); if (qdcount) { if (iquery) { if ((n = dn_expand((u_char *)answer->buf, (u_char *)eom, (u_char *)cp, (u_char *)bp, buflen)) < 0) { h_errno = NO_RECOVERY; return ((struct hostent *) NULL); } cp += n + QFIXEDSZ; host.h_name = bp; n = strlen(bp) + 1; bp += n; buflen -= n; } else cp += __dn_skipname(cp, eom) + QFIXEDSZ; while (--qdcount > 0) cp += __dn_skipname(cp, eom) + QFIXEDSZ; } else if (iquery) { if (hp->aa) h_errno = HOST_NOT_FOUND; else h_errno = TRY_AGAIN; return ((struct hostent *) NULL); } ap = host_aliases; *ap = NULL; host.h_aliases = host_aliases; hap = h_addr_ptrs; *hap = NULL; #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ host.h_addr_list = h_addr_ptrs; #endif haveanswer = 0; while (--ancount >= 0 && cp < eom) { if ((n = dn_expand((u_char *)answer->buf, (u_char *)eom, (u_char *)cp, (u_char *)bp, buflen)) < 0) break; cp += n; type = _getshort(cp); cp += sizeof(u_short); class = _getshort(cp); cp += sizeof(u_short) + sizeof(u_long); n = _getshort(cp); cp += sizeof(u_short); if (type == T_CNAME) { cp += n; if (ap >= &host_aliases[MAXALIASES-1]) continue; *ap++ = bp; n = strlen(bp) + 1; bp += n; buflen -= n; continue; } if (iquery && type == T_PTR) { if ((n = dn_expand((u_char *)answer->buf, (u_char *)eom, (u_char *)cp, (u_char *)bp, buflen)) < 0) { cp += n; continue; } cp += n; host.h_name = bp; return(&host); } if (iquery || type != T_A) { #ifdef DEBUG if (_res.options & RES_DEBUG) printf("unexpected answer type %d, size %d\n", type, n); #endif cp += n; continue; } if (haveanswer) { if (n != host.h_length) { cp += n; continue; } if (class != getclass) { cp += n; continue; } } else { host.h_length = n; getclass = class; host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC; if (!iquery) { host.h_name = bp; bp += strlen(bp) + 1; } } bp += sizeof(align) - ((u_long)bp % sizeof(align)); if (bp + n >= &hostbuf[sizeof(hostbuf)]) { #ifdef DEBUG if (_res.options & RES_DEBUG) printf("size (%d) too big\n", n); #endif break; } bcopy(cp, *hap++ = bp, n); bp +=n; cp += n; haveanswer++; } if (haveanswer) { *ap = NULL; #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ *hap = NULL; #else host.h_addr = h_addr_ptrs[0]; #endif return (&host); } else { h_errno = TRY_AGAIN; return ((struct hostent *) NULL); } } struct hostent * gethostbyname(name) char *name; { querybuf buf; register char *cp; int n, i; extern struct hostent *_gethtbyname(), *_yp_gethtbyname(); register struct hostent *hp; char lookups[MAXDNSLUS]; /* * disallow names consisting only of digits/dots, unless * they end in a dot. */ if (isdigit(name[0])) for (cp = name;; ++cp) { if (!*cp) { if (*--cp == '.') break; /* * All-numeric, no dot at the end. * Fake up a hostent as if we'd actually * done a lookup. What if someone types * 255.255.255.255? The test below will * succeed spuriously... ??? */ if ((host_addr.s_addr = inet_addr(name)) == -1) { h_errno = HOST_NOT_FOUND; return((struct hostent *) NULL); } host.h_name = name; host.h_aliases = host_aliases; host_aliases[0] = NULL; host.h_addrtype = AF_INET; host.h_length = sizeof(u_long); h_addr_ptrs[0] = (char *)&host_addr; h_addr_ptrs[1] = (char *)0; #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ host.h_addr_list = h_addr_ptrs; #else host.h_addr = h_addr_ptrs[0]; #endif return (&host); } if (!isdigit(*cp) && *cp != '.') break; } if ((_res.options & RES_INIT) == 0 && res_init() == -1) return (_gethtbyname(name)); bcopy(_res.lookups, lookups, sizeof lookups); if (lookups[0] == '\0') { lookups[0] = 'b'; lookups[1] = 'f'; } hp = (struct hostent *)NULL; for (i = 0; i < MAXDNSLUS && hp == NULL && lookups[i]; i++) { switch (lookups[i]) { #ifdef YP case 'y': hp = _yp_gethtbyname(name); break; #endif case 'b': if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) { #ifdef DEBUG if (_res.options & RES_DEBUG) printf("res_search failed\n"); #endif break; } hp = getanswer(&buf, n, 0); break; case 'f': hp = _gethtbyname(name); break; } } return (hp); } struct hostent * gethostbyaddr(addr, len, type) const char *addr; int len, type; { int n, i; querybuf buf; register struct hostent *hp; char qbuf[MAXDNAME]; extern struct hostent *_gethtbyaddr(), *_yp_gethtbyaddr(); char lookups[MAXDNSLUS]; if (type != AF_INET) return ((struct hostent *) NULL); (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", ((unsigned)addr[3] & 0xff), ((unsigned)addr[2] & 0xff), ((unsigned)addr[1] & 0xff), ((unsigned)addr[0] & 0xff)); if ((_res.options & RES_INIT) == 0 && res_init() == -1) return (_gethtbyaddr(addr, len, type)); bcopy(_res.lookups, lookups, sizeof lookups); if (lookups[0] == '\0') { lookups[0] = 'b'; lookups[1] = 'f'; } hp = (struct hostent *)NULL; for (i = 0; i < MAXDNSLUS && hp == NULL && lookups[i]; i++) { switch (lookups[i]) { #ifdef YP case 'y': hp = _yp_gethtbyaddr(addr, len, type); break; #endif case 'b': n = res_query(qbuf, C_IN, T_PTR, (char *)&buf, sizeof(buf)); if (n < 0) { #ifdef DEBUG if (_res.options & RES_DEBUG) printf("res_query failed\n"); #endif break; } hp = getanswer(&buf, n, 1); if (hp == NULL) break; hp->h_addrtype = type; hp->h_length = len; h_addr_ptrs[0] = (char *)&host_addr; h_addr_ptrs[1] = (char *)0; host_addr = *(struct in_addr *)addr; #if BSD < 43 && !defined(h_addr) /* new-style hostent structure */ hp->h_addr = h_addr_ptrs[0]; #endif break; case 'f': hp = _gethtbyaddr(addr, len, type); break; } } return (hp); } _sethtent(f) int f; { if (hostf == NULL) hostf = fopen(_PATH_HOSTS, "r" ); else rewind(hostf); stayopen |= f; } _endhtent() { if (hostf && !stayopen) { (void) fclose(hostf); hostf = NULL; } } struct hostent * _gethtent() { char *p; register char *cp, **q; if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL) return (NULL); again: if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL) return (NULL); if (*p == '#') goto again; cp = strpbrk(p, "#\n"); if (cp == NULL) goto again; *cp = '\0'; cp = strpbrk(p, " \t"); if (cp == NULL) goto again; *cp++ = '\0'; /* THIS STUFF IS INTERNET SPECIFIC */ #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ host.h_addr_list = host_addrs; #endif host.h_addr = (char *)hostaddr; *((u_long *)host.h_addr) = inet_addr(p); host.h_length = sizeof (u_long); host.h_addrtype = AF_INET; while (*cp == ' ' || *cp == '\t') cp++; host.h_name = cp; q = host.h_aliases = host_aliases; cp = strpbrk(cp, " \t"); if (cp != NULL) *cp++ = '\0'; while (cp && *cp) { if (*cp == ' ' || *cp == '\t') { cp++; continue; } if (q < &host_aliases[MAXALIASES - 1]) *q++ = cp; cp = strpbrk(cp, " \t"); if (cp != NULL) *cp++ = '\0'; } *q = NULL; return (&host); } struct hostent * _gethtbyname(name) char *name; { register struct hostent *p; register char **cp; _sethtent(0); while (p = _gethtent()) { if (strcasecmp(p->h_name, name) == 0) break; for (cp = p->h_aliases; *cp != 0; cp++) if (strcasecmp(*cp, name) == 0) goto found; } found: _endhtent(); return (p); } struct hostent * _gethtbyaddr(addr, len, type) const char *addr; int len, type; { register struct hostent *p; _sethtent(0); while (p = _gethtent()) if (p->h_addrtype == type && !bcmp(p->h_addr, addr, len)) break; _endhtent(); return (p); } #ifdef YP struct hostent * _yphostent(line) char *line; { static struct hostent host; char *p = line; char *cp, **q; char **hap; u_long *buf; int more; host.h_name = NULL; #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ host.h_addr_list = h_addr_ptrs; #endif host.h_addr = (char *)hostaddr; host.h_length = sizeof (u_long); host.h_addrtype = AF_INET; hap = h_addr_ptrs; buf = hostaddr; q = host.h_aliases = host_aliases; nextline: more = 0; cp = strpbrk(p, " \t"); if (cp == NULL) { if (host.h_name == NULL) return (NULL); else return (&host); } *cp++ = '\0'; *hap++ = (char *)buf; *buf++ = inet_addr(p); while (*cp == ' ' || *cp == '\t') cp++; p = cp; cp = strpbrk(p, " \t\n"); if (cp != NULL) { if (*cp == '\n') more = 1; *cp++ = '\0'; } if (!host.h_name) host.h_name = p; else if (q < &host_aliases[MAXALIASES - 1]) *q++ = p; p = cp; if (more) goto nextline; while (cp && *cp) { if (*cp == ' ' || *cp == '\t') { cp++; continue; } if (*cp == '\n') { cp++; goto nextline; } if (q < &host_aliases[MAXALIASES - 1]) *q++ = cp; cp = strpbrk(cp, " \t"); if (cp != NULL) *cp++ = '\0'; } *q = NULL; #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ *hap = NULL; #else host.h_addr = h_addr_ptrs[0]; #endif return (&host); } struct hostent * _yp_gethtbyaddr(addr, len, type) const char *addr; int len, type; { struct hostent *hp = (struct hostent *)NULL; static char *__ypcurrent; int __ypcurrentlen, r; char name[sizeof("xxx.xxx.xxx.xxx") + 1]; if (!__ypdomain) { if (_yp_check(&__ypdomain) == 0) return (hp); } sprintf(name, "%u.%u.%u.%u", ((unsigned)addr[0] & 0xff), ((unsigned)addr[1] & 0xff), ((unsigned)addr[2] & 0xff), ((unsigned)addr[3] & 0xff)); if (__ypcurrent) free(__ypcurrent); __ypcurrent = NULL; r = yp_match(__ypdomain, "hosts.byaddr", name, strlen(name), &__ypcurrent, &__ypcurrentlen); if (r==0) hp = _yphostent(__ypcurrent); return (hp); } struct hostent * _yp_gethtbyname(name) const char *name; { struct hostent *hp = (struct hostent *)NULL; static char *__ypcurrent; int __ypcurrentlen, r; if (!__ypdomain) { if (_yp_check(&__ypdomain) == 0) return (hp); } if (__ypcurrent) free(__ypcurrent); __ypcurrent = NULL; r = yp_match(__ypdomain, "hosts.byname", name, strlen(name), &__ypcurrent, &__ypcurrentlen); if (r==0) hp = _yphostent(__ypcurrent); return (hp); } #endif