1/* 2 * Copyright (c) 1996,1999 by Internet Software Consortium. 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 11 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 12 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 13 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 14 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 15 * SOFTWARE. 16 */ 17 18#ifndef __APPLE__ 19#ifndef lint 20static const char rcsid[] = "$Id: ns_parse.c,v 1.1 2006/03/01 19:01:37 majka Exp $"; 21#endif 22#endif 23 24/* Import. */ 25 26#ifndef __APPLE__ 27#include "port_before.h" 28#endif 29 30#include <sys/types.h> 31 32#include <netinet/in.h> 33#include <arpa/nameser.h> 34 35#include <errno.h> 36#include <resolv.h> 37#include <string.h> 38 39#ifndef __APPLE__ 40#include "port_after.h" 41#endif 42 43/* Forward. */ 44 45static void setsection(ns_msg *msg, ns_sect sect); 46 47/* Macros. */ 48 49#define RETERR(err) do { errno = (err); return (-1); } while (0) 50 51/* Public. */ 52 53/* These need to be in the same order as the nres.h:ns_flag enum. */ 54struct _ns_flagdata _ns_flagdata[16] = { 55 { 0x8000, 15 }, /* qr. */ 56 { 0x7800, 11 }, /* opcode. */ 57 { 0x0400, 10 }, /* aa. */ 58 { 0x0200, 9 }, /* tc. */ 59 { 0x0100, 8 }, /* rd. */ 60 { 0x0080, 7 }, /* ra. */ 61 { 0x0040, 6 }, /* z. */ 62 { 0x0020, 5 }, /* ad. */ 63 { 0x0010, 4 }, /* cd. */ 64 { 0x000f, 0 }, /* rcode. */ 65 { 0x0000, 0 }, /* expansion (1/6). */ 66 { 0x0000, 0 }, /* expansion (2/6). */ 67 { 0x0000, 0 }, /* expansion (3/6). */ 68 { 0x0000, 0 }, /* expansion (4/6). */ 69 { 0x0000, 0 }, /* expansion (5/6). */ 70 { 0x0000, 0 }, /* expansion (6/6). */ 71}; 72 73int ns_msg_getflag(ns_msg handle, int flag) { 74 return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); 75} 76 77int 78ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { 79 const u_char *optr = ptr; 80 81 for ((void)NULL; count > 0; count--) { 82 int b, rdlength; 83 84 b = dn_skipname(ptr, eom); 85 if (b < 0) 86 RETERR(EMSGSIZE); 87 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; 88 if (section != ns_s_qd) { 89 if (ptr + NS_INT32SZ + NS_INT16SZ > eom) 90 RETERR(EMSGSIZE); 91 ptr += NS_INT32SZ/*TTL*/; 92 NS_GET16(rdlength, ptr); 93 ptr += rdlength/*RData*/; 94 } 95 } 96 if (ptr > eom) 97 RETERR(EMSGSIZE); 98 return (ptr - optr); 99} 100 101int 102ns_initparse(const u_char *msg, int msglen, ns_msg *handle) { 103 const u_char *eom = msg + msglen; 104 int i; 105 106 memset(handle, 0x5e, sizeof *handle); 107 handle->_msg = msg; 108 handle->_eom = eom; 109 if (msg + NS_INT16SZ > eom) 110 RETERR(EMSGSIZE); 111 NS_GET16(handle->_id, msg); 112 if (msg + NS_INT16SZ > eom) 113 RETERR(EMSGSIZE); 114 NS_GET16(handle->_flags, msg); 115 for (i = 0; i < ns_s_max; i++) { 116 if (msg + NS_INT16SZ > eom) 117 RETERR(EMSGSIZE); 118 NS_GET16(handle->_counts[i], msg); 119 } 120 for (i = 0; i < ns_s_max; i++) 121 if (handle->_counts[i] == 0) 122 handle->_sections[i] = NULL; 123 else { 124 int b = ns_skiprr(msg, eom, (ns_sect)i, 125 handle->_counts[i]); 126 127 if (b < 0) 128 return (-1); 129 handle->_sections[i] = msg; 130 msg += b; 131 } 132 if (msg != eom) 133 RETERR(EMSGSIZE); 134 setsection(handle, ns_s_max); 135 return (0); 136} 137 138int 139ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { 140 int b; 141 142 /* Make section right. */ 143 if (section >= ns_s_max) 144 RETERR(ENODEV); 145 if (section != handle->_sect) 146 setsection(handle, section); 147 148 /* Make rrnum right. */ 149 if (rrnum == -1) 150 rrnum = handle->_rrnum; 151 if (rrnum < 0 || rrnum >= handle->_counts[(int)section]) 152 RETERR(ENODEV); 153 if (rrnum < handle->_rrnum) 154 setsection(handle, section); 155 if (rrnum > handle->_rrnum) { 156 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section, 157 rrnum - handle->_rrnum); 158 159 if (b < 0) 160 return (-1); 161 handle->_msg_ptr += b; 162 handle->_rrnum = rrnum; 163 } 164 165 /* Do the parse. */ 166 b = dn_expand(handle->_msg, handle->_eom, 167 handle->_msg_ptr, rr->name, NS_MAXDNAME); 168 if (b < 0) 169 return (-1); 170 handle->_msg_ptr += b; 171 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) 172 RETERR(EMSGSIZE); 173 NS_GET16(rr->type, handle->_msg_ptr); 174 NS_GET16(rr->rr_class, handle->_msg_ptr); 175 if (section == ns_s_qd) { 176 rr->ttl = 0; 177 rr->rdlength = 0; 178 rr->rdata = NULL; 179 } else { 180 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) 181 RETERR(EMSGSIZE); 182 NS_GET32(rr->ttl, handle->_msg_ptr); 183 NS_GET16(rr->rdlength, handle->_msg_ptr); 184 if (handle->_msg_ptr + rr->rdlength > handle->_eom) 185 RETERR(EMSGSIZE); 186 rr->rdata = handle->_msg_ptr; 187 handle->_msg_ptr += rr->rdlength; 188 } 189 if (++handle->_rrnum > handle->_counts[(int)section]) 190 setsection(handle, (ns_sect)((int)section + 1)); 191 192 /* All done. */ 193 return (0); 194} 195 196/* Private. */ 197 198static void 199setsection(ns_msg *msg, ns_sect sect) { 200 msg->_sect = sect; 201 if (sect == ns_s_max) { 202 msg->_rrnum = -1; 203 msg->_msg_ptr = NULL; 204 } else { 205 msg->_rrnum = 0; 206 msg->_msg_ptr = msg->_sections[(int)sect]; 207 } 208} 209