/* $OpenBSD: getnetnamadr.c,v 1.5 2002/11/14 02:54:22 millert Exp $ */ /* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro * Dep. Matematica Universidade de Coimbra, Portugal, Europe * * 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. */ /* * Copyright (c) 1983, 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. */ #if defined(LIBC_SCCS) && !defined(lint) #if 0 static char sccsid[] = "@(#)getnetbyaddr.c 8.1 (Berkeley) 6/4/93"; static char sccsid_[] = "from getnetnamadr.c 1.4 (Coimbra) 93/06/03"; static char rcsid[] = "$From: getnetnamadr.c,v 8.8 1997/06/01 20:34:37 vixie Exp $"; #else static char rcsid[] = "$OpenBSD: getnetnamadr.c,v 1.5 2002/11/14 02:54:22 millert Exp $"; #endif #endif /* LIBC_SCCS and not lint */ #include #include #include #include #include #include #include #include #include #include #include #include extern int h_errno; #if defined(mips) && defined(SYSTYPE_BSD43) extern int errno; #endif struct netent *_getnetbyaddr(long net, int type); struct netent *_getnetbyname(const char *name); #define BYADDR 0 #define BYNAME 1 #define MAXALIASES 35 #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; static struct netent * getnetanswer(answer, anslen, net_i) querybuf *answer; int anslen; int net_i; { register HEADER *hp; register u_char *cp; register int n; u_char *eom; int type, class, ancount, qdcount, haveanswer, i, nchar; char aux1[30], aux2[30], *in, *st, *pauxt, *bp, **ap, *paux1 = &aux1[0], *paux2 = &aux2[0], *ep; static struct netent net_entry; static char *net_aliases[MAXALIASES], netbuf[PACKETSZ]; static char ans[MAXDNAME]; /* * find first satisfactory answer * * answer --> +------------+ ( MESSAGE ) * | Header | * +------------+ * | Question | the question for the name server * +------------+ * | Answer | RRs answering the question * +------------+ * | Authority | RRs pointing toward an authority * | Additional | RRs holding additional information * +------------+ */ eom = answer->buf + anslen; hp = &answer->hdr; ancount = ntohs(hp->ancount); /* #/records in the answer section */ qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ bp = netbuf; ep = netbuf + sizeof(netbuf); cp = answer->buf + HFIXEDSZ; if (!qdcount) { if (hp->aa) h_errno = HOST_NOT_FOUND; else h_errno = TRY_AGAIN; return (NULL); } while (qdcount-- > 0) { n = __dn_skipname(cp, eom); if (n < 0 || (cp + n + QFIXEDSZ) > eom) { h_errno = NO_RECOVERY; return(NULL); } cp += n + QFIXEDSZ; } ap = net_aliases; *ap = NULL; net_entry.n_aliases = net_aliases; haveanswer = 0; while (--ancount >= 0 && cp < eom) { n = dn_expand(answer->buf, eom, cp, bp, ep - bp); if ((n < 0) || !res_dnok(bp)) break; cp += n; ans[0] = '\0'; (void)strcpy(ans, bp); GETSHORT(type, cp); GETSHORT(class, cp); cp += INT32SZ; /* TTL */ GETSHORT(n, cp); if (class == C_IN && type == T_PTR) { n = dn_expand(answer->buf, eom, cp, bp, ep - bp); if ((n < 0) || !res_hnok(bp)) { cp += n; return (NULL); } cp += n; if ((ap + 2) < &net_aliases[MAXALIASES]) { *ap++ = bp; bp += strlen(bp) + 1; net_entry.n_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC; haveanswer++; } } } if (haveanswer) { *ap = NULL; switch (net_i) { case BYADDR: net_entry.n_name = *net_entry.n_aliases; net_entry.n_net = 0L; break; case BYNAME: ap = net_entry.n_aliases; next_alias: in = *ap++; if (in == NULL) { h_errno = HOST_NOT_FOUND; return (NULL); } net_entry.n_name = ans; aux2[0] = '\0'; for (i = 0; i < 4; i++) { for (st = in, nchar = 0; isdigit((unsigned char)*st); st++, nchar++) ; if (*st != '.' || nchar == 0 || nchar > 3) goto next_alias; if (i != 0) nchar++; (void)strncpy(paux1, in, nchar); paux1[nchar] = '\0'; pauxt = paux2; paux2 = strcat(paux1, paux2); paux1 = pauxt; in = ++st; } if (strcasecmp(in, "IN-ADDR.ARPA") != 0) goto next_alias; net_entry.n_net = inet_network(paux2); break; } net_entry.n_aliases++; return (&net_entry); } h_errno = TRY_AGAIN; return (NULL); } struct netent * getnetbyaddr(net, net_type) register u_long net; register int net_type; { unsigned int netbr[4]; int nn, anslen; querybuf buf; char qbuf[MAXDNAME]; unsigned long net2; struct netent *net_entry; if (net_type != AF_INET) return (_getnetbyaddr(net, net_type)); for (nn = 4, net2 = net; net2; net2 >>= 8) netbr[--nn] = net2 & 0xff; switch (nn) { case 3: /* Class A */ sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); break; case 2: /* Class B */ sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); break; case 1: /* Class C */ sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], netbr[1]); break; case 0: /* Class D - E */ sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], netbr[1], netbr[0]); break; } anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf)); if (anslen < 0) { #ifdef DEBUG if (_res.options & RES_DEBUG) printf("res_query failed\n"); #endif if (errno == ECONNREFUSED) return (_getnetbyaddr(net, net_type)); return (NULL); } net_entry = getnetanswer(&buf, anslen, BYADDR); if (net_entry) { unsigned u_net = net; /* maybe net should be unsigned ? */ /* Strip trailing zeros */ while ((u_net & 0xff) == 0 && u_net != 0) u_net >>= 8; net_entry->n_net = u_net; return (net_entry); } return (_getnetbyaddr(net, net_type)); } struct netent * getnetbyname(net) register const char *net; { int anslen; querybuf buf; char qbuf[MAXDNAME]; struct netent *net_entry; if ((_res.options & RES_INIT) == 0 && res_init() == -1) { h_errno = NETDB_INTERNAL; return (NULL); } strcpy(&qbuf[0], net); anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf)); if (anslen < 0) { #ifdef DEBUG if (_res.options & RES_DEBUG) printf("res_query failed\n"); #endif if (errno == ECONNREFUSED) return (_getnetbyname(net)); return (_getnetbyname(net)); } net_entry = getnetanswer(&buf, anslen, BYNAME); if (net_entry) return (net_entry); return (_getnetbyname(net)); }