getnetnamadr.c revision 1.2
1 /* $NetBSD: getnetnamadr.c,v 1.2 1997/07/20 13:33:22 mrg Exp $ */ 2 3 /* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro 4 * Dep. Matematica Universidade de Coimbra, Portugal, Europe 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 */ 10 /* 11 * Copyright (c) 1983, 1993 12 * The Regents of the University of California. All rights reserved. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 */ 42 43 #include <sys/cdefs.h> 44 #if defined(LIBC_SCCS) && !defined(lint) 45 #if 0 46 static char sccsid[] = "@(#)getnetbyaddr.c 8.1 (Berkeley) 6/4/93"; 47 static char sccsid_[] = "from getnetnamadr.c 1.4 (Coimbra) 93/06/03"; 48 static char rcsid[] = "$Id: getnetnamadr.c,v 8.8 1997/06/01 20:34:37 vixie Exp "; 49 #else 50 __RCSID("$NetBSD: getnetnamadr.c,v 1.2 1997/07/20 13:33:22 mrg Exp $"); 51 #endif 52 #endif /* LIBC_SCCS and not lint */ 53 54 #include <sys/types.h> 55 #include <sys/param.h> 56 #include <sys/socket.h> 57 #include <netinet/in.h> 58 #include <arpa/inet.h> 59 #include <arpa/nameser.h> 60 61 #include <stdio.h> 62 #include <netdb.h> 63 #include <resolv.h> 64 #include <ctype.h> 65 #include <errno.h> 66 #include <string.h> 67 68 extern int h_errno; 69 70 #if defined(mips) && defined(SYSTYPE_BSD43) 71 extern int errno; 72 #endif 73 74 struct netent *_getnetbyaddr __P((long net, int type)); 75 struct netent *_getnetbyname __P((const char *name)); 76 77 #define BYADDR 0 78 #define BYNAME 1 79 #define MAXALIASES 35 80 81 #if PACKETSZ > 1024 82 #define MAXPACKET PACKETSZ 83 #else 84 #define MAXPACKET 1024 85 #endif 86 87 typedef union { 88 HEADER hdr; 89 u_char buf[MAXPACKET]; 90 } querybuf; 91 92 typedef union { 93 long al; 94 char ac; 95 } align; 96 97 static struct netent *getnetanswer __P((querybuf *, int, int)); 98 static struct netent * 99 getnetanswer(answer, anslen, net_i) 100 querybuf *answer; 101 int anslen; 102 int net_i; 103 { 104 105 register HEADER *hp; 106 register u_char *cp; 107 register int n; 108 u_char *eom; 109 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar; 110 char aux1[30], aux2[30], ans[30], *in, *st, *pauxt, *bp, **ap, 111 *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0; 112 static struct netent net_entry; 113 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ]; 114 115 /* 116 * find first satisfactory answer 117 * 118 * answer --> +------------+ ( MESSAGE ) 119 * | Header | 120 * +------------+ 121 * | Question | the question for the name server 122 * +------------+ 123 * | Answer | RRs answering the question 124 * +------------+ 125 * | Authority | RRs pointing toward an authority 126 * | Additional | RRs holding additional information 127 * +------------+ 128 */ 129 eom = answer->buf + anslen; 130 hp = &answer->hdr; 131 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 132 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 133 bp = netbuf; 134 buflen = sizeof(netbuf); 135 cp = answer->buf + HFIXEDSZ; 136 if (!qdcount) { 137 if (hp->aa) 138 h_errno = HOST_NOT_FOUND; 139 else 140 h_errno = TRY_AGAIN; 141 return (NULL); 142 } 143 while (qdcount-- > 0) 144 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 145 ap = net_aliases; 146 *ap = NULL; 147 net_entry.n_aliases = net_aliases; 148 haveanswer = 0; 149 while (--ancount >= 0 && cp < eom) { 150 n = dn_expand(answer->buf, eom, cp, bp, buflen); 151 if ((n < 0) || !res_dnok(bp)) 152 break; 153 cp += n; 154 ans[0] = '\0'; 155 (void)strcpy(&ans[0], bp); 156 GETSHORT(type, cp); 157 GETSHORT(class, cp); 158 cp += INT32SZ; /* TTL */ 159 GETSHORT(n, cp); 160 if (class == C_IN && type == T_PTR) { 161 n = dn_expand(answer->buf, eom, cp, bp, buflen); 162 if ((n < 0) || !res_hnok(bp)) { 163 cp += n; 164 return (NULL); 165 } 166 cp += n; 167 *ap++ = bp; 168 bp += strlen(bp) + 1; 169 net_entry.n_addrtype = 170 (class == C_IN) ? AF_INET : AF_UNSPEC; 171 haveanswer++; 172 } 173 } 174 if (haveanswer) { 175 *ap = NULL; 176 switch (net_i) { 177 case BYADDR: 178 net_entry.n_name = *net_entry.n_aliases; 179 net_entry.n_net = 0L; 180 break; 181 case BYNAME: 182 in = *net_entry.n_aliases; 183 net_entry.n_name = &ans[0]; 184 aux2[0] = '\0'; 185 for (i = 0; i < 4; i++) { 186 for (st = in, nchar = 0; 187 *st != '.'; 188 st++, nchar++) 189 ; 190 if (nchar != 1 || *in != '0' || flag) { 191 flag = 1; 192 (void)strncpy(paux1, 193 (i==0) ? in : in-1, 194 (i==0) ?nchar : nchar+1); 195 paux1[(i==0) ? nchar : nchar+1] = '\0'; 196 pauxt = paux2; 197 paux2 = strcat(paux1, paux2); 198 paux1 = pauxt; 199 } 200 in = ++st; 201 } 202 net_entry.n_net = inet_network(paux2); 203 break; 204 } 205 net_entry.n_aliases++; 206 return (&net_entry); 207 } 208 h_errno = TRY_AGAIN; 209 return (NULL); 210 } 211 212 struct netent * 213 getnetbyaddr(net, net_type) 214 register u_long net; 215 register int net_type; 216 { 217 unsigned int netbr[4]; 218 int nn, anslen; 219 querybuf buf; 220 char qbuf[MAXDNAME]; 221 unsigned long net2; 222 struct netent *net_entry; 223 224 if (net_type != AF_INET) 225 return (_getnetbyaddr(net, net_type)); 226 227 for (nn = 4, net2 = net; net2; net2 >>= 8) 228 netbr[--nn] = net2 & 0xff; 229 switch (nn) { 230 case 3: /* Class A */ 231 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 232 break; 233 case 2: /* Class B */ 234 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 235 break; 236 case 1: /* Class C */ 237 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 238 netbr[1]); 239 break; 240 case 0: /* Class D - E */ 241 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 242 netbr[1], netbr[0]); 243 break; 244 } 245 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf)); 246 if (anslen < 0) { 247 #ifdef DEBUG 248 if (_res.options & RES_DEBUG) 249 printf("res_query failed\n"); 250 #endif 251 if (errno == ECONNREFUSED) 252 return (_getnetbyaddr(net, net_type)); 253 return (NULL); 254 } 255 net_entry = getnetanswer(&buf, anslen, BYADDR); 256 if (net_entry) { 257 unsigned u_net = net; /* maybe net should be unsigned ? */ 258 259 /* Strip trailing zeros */ 260 while ((u_net & 0xff) == 0 && u_net != 0) 261 u_net >>= 8; 262 net_entry->n_net = u_net; 263 return (net_entry); 264 } 265 return (_getnetbyaddr(net, net_type)); 266 } 267 268 struct netent * 269 getnetbyname(net) 270 register const char *net; 271 { 272 int anslen; 273 querybuf buf; 274 char qbuf[MAXDNAME]; 275 struct netent *net_entry; 276 277 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 278 h_errno = NETDB_INTERNAL; 279 return (NULL); 280 } 281 strcpy(&qbuf[0], net); 282 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf)); 283 if (anslen < 0) { 284 #ifdef DEBUG 285 if (_res.options & RES_DEBUG) 286 printf("res_query failed\n"); 287 #endif 288 if (errno == ECONNREFUSED) 289 return (_getnetbyname(net)); 290 return (_getnetbyname(net)); 291 } 292 net_entry = getnetanswer(&buf, anslen, BYNAME); 293 if (net_entry) 294 return (net_entry); 295 return (_getnetbyname(net)); 296 } 297
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