/*- * Copyright (c) 1985, 1988, 1993 * The 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. * - * Portions Copyright (c) 1993 by Digital Equipment Corporation. * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies, and that * the name of Digital Equipment Corporation not be used in advertising or * publicity pertaining to distribution of the document or software without * specific, written prior permission. * * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS * SOFTWARE. * - * --Copyright-- */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93"; static char rcsid[] = "$Id: gethostbydns.c,v 1.3 1994/12/01 22:25:38 wollman Exp $"; #endif /* LIBC_SCCS and not lint */ #include #include #include #include #include #include #include #include #include #include #include #include #define BYADDR 0 #define BYNAME 1 #define MAXALIASES 35 #define MAXADDRS 35 #define MULTI_PTRS_ARE_ALIASES 1 /* XXX - experimental */ static const char AskedForGot[] = "gethostby*.gethostanswer: asked for \"%s\", got \"%s\""; static char *h_addr_ptrs[MAXADDRS + 1]; static struct hostent host; static char *host_aliases[MAXALIASES]; static char hostbuf[8*1024]; static struct in_addr host_addr; static FILE *hostf = NULL; static char hostaddr[MAXADDRS]; static char *host_addrs[2]; static int stayopen = 0; #if PACKETSZ > 1024 #define MAXPACKET PACKETSZ #else #define MAXPACKET 1024 #endif typedef union { HEADER hdr; u_char buf[MAXPACKET]; } querybuf; typedef union { int32_t al; char ac; } align; extern int h_errno; #ifdef RESOLVSORT static void addrsort(ap, num) char **ap; int num; { int i, j; char **p; short aval[MAXADDRS]; int needsort = 0; p = ap; for (i = 0; i < num; i++, p++) { for (j = 0 ; j < _res.nsort; j++) if (_res.sort_list[j].addr.s_addr == (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask)) break; aval[i] = j; if (needsort == 0 && i > 0 && j < aval[i-1]) needsort = i; } if (!needsort) return; while (needsort < num) { for (j = needsort - 1; j >= 0; j--) { if (aval[j] > aval[j+1]) { char *hp; i = aval[j]; aval[j] = aval[j+1]; aval[j+1] = i; hp = ap[j]; ap[j] = ap[j+1]; ap[j+1] = hp; } else break; } needsort++; } } #endif static struct hostent * gethostanswer(answer, anslen, qname, qclass, qtype) const querybuf *answer; int anslen; const char *qname; int qclass, qtype; { register const HEADER *hp; register const u_char *cp; register int n; const u_char *eom; char *bp, **ap, **hap; int type, class, buflen, ancount, qdcount; int haveanswer, had_error; int toobig = 0; char tbuf[MAXDNAME+1]; host.h_name = NULL; 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 + HFIXEDSZ; if (qdcount != 1) { h_errno = NO_RECOVERY; return (NULL); } if ((n = dn_expand(answer->buf, eom, cp, bp, buflen)) < 0) { h_errno = NO_RECOVERY; return (NULL); } cp += n + QFIXEDSZ; if (qtype == T_A) { /* res_send() has already verified that the query name is the * same as the one we sent; this just gets the expanded name * (i.e., with the succeeding search-domain tacked on). */ n = strlen(bp) + 1; /* for the \0 */ host.h_name = bp; bp += n; buflen -= n; /* The qname can be abbreviated, but h_name is now absolute. */ qname = host.h_name; } ap = host_aliases; *ap = NULL; host.h_aliases = host_aliases; hap = h_addr_ptrs; *hap = NULL; host.h_addr_list = h_addr_ptrs; haveanswer = 0; had_error = 0; while (ancount-- > 0 && cp < eom && !had_error) { n = dn_expand(answer->buf, eom, cp, bp, buflen); if (n < 0) { had_error++; continue; } cp += n; /* name */ type = _getshort(cp); cp += INT16SZ; /* type */ class = _getshort(cp); cp += INT16SZ + INT32SZ; /* class, TTL */ n = _getshort(cp); cp += INT16SZ; /* len */ if (class != qclass) { /* XXX - debug? syslog? */ cp += n; continue; /* XXX - had_error++ ? */ } if (qtype == T_A && type == T_CNAME) { if (ap >= &host_aliases[MAXALIASES-1]) continue; n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); if (n < 0) { had_error++; continue; } cp += n; if (host.h_name && strcasecmp(host.h_name, bp) != 0) { syslog(LOG_NOTICE|LOG_AUTH, "gethostby*.getanswer: asked for \"%s\", got CNAME for \"%s\"", host.h_name, bp); continue; /* XXX - had_error++ ? */ } /* Store alias. */ *ap++ = bp; n = strlen(bp) + 1; /* for the \0 */ bp += n; buflen -= n; /* Get canonical name. */ n = strlen(tbuf) + 1; /* for the \0 */ if (n > buflen) { had_error++; continue; } strcpy(bp, tbuf); host.h_name = bp; bp += n; buflen -= n; continue; } if (type != qtype) { syslog(LOG_NOTICE|LOG_AUTH, "gethostby*.getanswer: asked for type %d(%s), got %d(%s)", qtype, qname, type, bp); cp += n; continue; /* XXX - had_error++ ? */ } switch (type) { case T_PTR: if (strcasecmp(qname, bp) != 0) { syslog(LOG_NOTICE|LOG_AUTH, AskedForGot, qname, bp); cp += n; continue; /* XXX - had_error++ ? */ } n = dn_expand(answer->buf, eom, cp, bp, buflen); if (n < 0) { had_error++; break; } #if MULTI_PTRS_ARE_ALIASES cp += n; if (!haveanswer) host.h_name = bp; else if (ap < &host_aliases[MAXALIASES-1]) *ap++ = bp; else n = -1; if (n != -1) { n = strlen(bp) + 1; /* for the \0 */ bp += n; buflen -= n; } break; #else host.h_name = bp; return (&host); #endif case T_A: if (strcasecmp(host.h_name, bp) != 0) { syslog(LOG_NOTICE|LOG_AUTH, AskedForGot, host.h_name, bp); cp += n; continue; /* XXX - had_error++ ? */ } if (haveanswer) { if (n != host.h_length) { cp += n; continue; } } else { register int nn; host.h_length = n; host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC; host.h_name = bp; nn = strlen(bp) + 1; /* for the \0 */ bp += nn; buflen -= nn; } bp += sizeof(align) - ((u_long)bp % sizeof(align)); if (bp + n >= &hostbuf[sizeof hostbuf]) { if (_res.options & RES_DEBUG) printf("size (%d) too big\n", n); had_error++; continue; } if (hap >= &h_addr_ptrs[MAXADDRS-1]) { if (_res.options & RES_DEBUG && !toobig++) printf("Too many addresses (%d)\n", MAXADDRS); cp += n; continue; } bcopy(cp, *hap++ = bp, n); bp += n; cp += n; break; default: abort(); } /*switch*/ if (!had_error) haveanswer++; } /*while*/ if (haveanswer) { *ap = NULL; *hap = NULL; # if defined(RESOLVSORT) /* * Note: we sort even if host can take only one address * in its return structures - should give it the "best" * address in that case, not some random one */ if (_res.nsort && haveanswer > 1 && qclass == C_IN && qtype == T_A) addrsort(h_addr_ptrs, haveanswer); # endif /*RESOLVSORT*/ if (!host.h_name) { n = strlen(qname) + 1; /* for the \0 */ strcpy(bp, qname); host.h_name = bp; } return (&host); } else { h_errno = TRY_AGAIN; return (NULL); } } struct hostent * _gethostbydnsname(name) const char *name; { querybuf buf; register const char *cp; int n; /* * 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. */ if (!inet_aton(name, &host_addr)) { h_errno = HOST_NOT_FOUND; return (NULL); } host.h_name = (char *)name; host.h_aliases = host_aliases; host_aliases[0] = NULL; host.h_addrtype = AF_INET; host.h_length = INT32SZ; h_addr_ptrs[0] = (char *)&host_addr; h_addr_ptrs[1] = NULL; host.h_addr_list = h_addr_ptrs; return (&host); } if (!isdigit(*cp) && *cp != '.') break; } if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) { if (_res.options & RES_DEBUG) printf("res_search failed\n"); return (NULL); } return (gethostanswer(&buf, n, name, C_IN, T_A)); } struct hostent * _gethostbydnsaddr(addr, len, type) const char *addr; int len, type; { int n; querybuf buf; register struct hostent *hp; char qbuf[MAXDNAME+1]; int o_res_options = _res.options; if (type != AF_INET) return (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)); _res.options |= RES_RECURSE; n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf); _res.options = o_res_options; if (n < 0) { if (_res.options & RES_DEBUG) printf("res_query failed\n"); return (NULL); } if (!(hp = gethostanswer(&buf, n, qbuf, C_IN, T_PTR))) return (NULL); hp->h_addrtype = type; hp->h_length = len; h_addr_ptrs[0] = (char *)&host_addr; h_addr_ptrs[1] = NULL; host_addr = *(struct in_addr *)addr; #if BSD < 43 && !defined(h_addr) /* new-style hostent structure */ hp->h_addr = h_addr_ptrs[0]; #endif return (hp); } void _sethostdnsent(stayopen) int stayopen; { if (stayopen) _res.options |= RES_STAYOPEN | RES_USEVC; } void _endhostdnsent() { _res.options &= ~(RES_STAYOPEN | RES_USEVC); _res_close(); }