ns_parse.c revision 174223
1/* 2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 3 * Copyright (c) 1996,1999 by Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18#ifndef lint 19static const char rcsid[] = "$Id: ns_parse.c,v 1.5.18.4 2007/08/27 03:34:24 marka Exp $"; 20#endif 21 22/* Import. */ 23 24#include "port_before.h" 25 26#include <sys/types.h> 27 28#include <netinet/in.h> 29#include <arpa/nameser.h> 30 31#include <errno.h> 32#include <resolv.h> 33#include <string.h> 34 35#include "port_after.h" 36 37/* Forward. */ 38 39static void setsection(ns_msg *msg, ns_sect sect); 40 41/* Macros. */ 42 43#if !defined(SOLARIS2) || defined(__COVERITY__) 44#define RETERR(err) do { errno = (err); return (-1); } while (0) 45#else 46#define RETERR(err) \ 47 do { errno = (err); if (errno == errno) return (-1); } while (0) 48#endif 49 50/* Public. */ 51 52/* These need to be in the same order as the nres.h:ns_flag enum. */ 53struct _ns_flagdata _ns_flagdata[16] = { 54 { 0x8000, 15 }, /*%< qr. */ 55 { 0x7800, 11 }, /*%< opcode. */ 56 { 0x0400, 10 }, /*%< aa. */ 57 { 0x0200, 9 }, /*%< tc. */ 58 { 0x0100, 8 }, /*%< rd. */ 59 { 0x0080, 7 }, /*%< ra. */ 60 { 0x0040, 6 }, /*%< z. */ 61 { 0x0020, 5 }, /*%< ad. */ 62 { 0x0010, 4 }, /*%< cd. */ 63 { 0x000f, 0 }, /*%< rcode. */ 64 { 0x0000, 0 }, /*%< expansion (1/6). */ 65 { 0x0000, 0 }, /*%< expansion (2/6). */ 66 { 0x0000, 0 }, /*%< expansion (3/6). */ 67 { 0x0000, 0 }, /*%< expansion (4/6). */ 68 { 0x0000, 0 }, /*%< expansion (5/6). */ 69 { 0x0000, 0 }, /*%< expansion (6/6). */ 70}; 71 72int ns_msg_getflag(ns_msg handle, int flag) { 73 return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); 74} 75 76int 77ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { 78 const u_char *optr = ptr; 79 80 for ((void)NULL; count > 0; count--) { 81 int b, rdlength; 82 83 b = dn_skipname(ptr, eom); 84 if (b < 0) 85 RETERR(EMSGSIZE); 86 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; 87 if (section != ns_s_qd) { 88 if (ptr + NS_INT32SZ + NS_INT16SZ > eom) 89 RETERR(EMSGSIZE); 90 ptr += NS_INT32SZ/*TTL*/; 91 NS_GET16(rdlength, ptr); 92 ptr += rdlength/*RData*/; 93 } 94 } 95 if (ptr > eom) 96 RETERR(EMSGSIZE); 97 return (ptr - optr); 98} 99 100int 101ns_initparse(const u_char *msg, int msglen, ns_msg *handle) { 102 const u_char *eom = msg + msglen; 103 int i; 104 105 memset(handle, 0x5e, sizeof *handle); 106 handle->_msg = msg; 107 handle->_eom = eom; 108 if (msg + NS_INT16SZ > eom) 109 RETERR(EMSGSIZE); 110 NS_GET16(handle->_id, msg); 111 if (msg + NS_INT16SZ > eom) 112 RETERR(EMSGSIZE); 113 NS_GET16(handle->_flags, msg); 114 for (i = 0; i < ns_s_max; i++) { 115 if (msg + NS_INT16SZ > eom) 116 RETERR(EMSGSIZE); 117 NS_GET16(handle->_counts[i], msg); 118 } 119 for (i = 0; i < ns_s_max; i++) 120 if (handle->_counts[i] == 0) 121 handle->_sections[i] = NULL; 122 else { 123 int b = ns_skiprr(msg, eom, (ns_sect)i, 124 handle->_counts[i]); 125 126 if (b < 0) 127 return (-1); 128 handle->_sections[i] = msg; 129 msg += b; 130 } 131 if (msg != eom) 132 RETERR(EMSGSIZE); 133 setsection(handle, ns_s_max); 134 return (0); 135} 136 137int 138ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { 139 int b; 140 int tmp; 141 142 /* Make section right. */ 143 tmp = section; 144 if (tmp < 0 || section >= ns_s_max) 145 RETERR(ENODEV); 146 if (section != handle->_sect) 147 setsection(handle, section); 148 149 /* Make rrnum right. */ 150 if (rrnum == -1) 151 rrnum = handle->_rrnum; 152 if (rrnum < 0 || rrnum >= handle->_counts[(int)section]) 153 RETERR(ENODEV); 154 if (rrnum < handle->_rrnum) 155 setsection(handle, section); 156 if (rrnum > handle->_rrnum) { 157 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section, 158 rrnum - handle->_rrnum); 159 160 if (b < 0) 161 return (-1); 162 handle->_msg_ptr += b; 163 handle->_rrnum = rrnum; 164 } 165 166 /* Do the parse. */ 167 b = dn_expand(handle->_msg, handle->_eom, 168 handle->_msg_ptr, rr->name, NS_MAXDNAME); 169 if (b < 0) 170 return (-1); 171 handle->_msg_ptr += b; 172 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) 173 RETERR(EMSGSIZE); 174 NS_GET16(rr->type, handle->_msg_ptr); 175 NS_GET16(rr->rr_class, handle->_msg_ptr); 176 if (section == ns_s_qd) { 177 rr->ttl = 0; 178 rr->rdlength = 0; 179 rr->rdata = NULL; 180 } else { 181 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) 182 RETERR(EMSGSIZE); 183 NS_GET32(rr->ttl, handle->_msg_ptr); 184 NS_GET16(rr->rdlength, handle->_msg_ptr); 185 if (handle->_msg_ptr + rr->rdlength > handle->_eom) 186 RETERR(EMSGSIZE); 187 rr->rdata = handle->_msg_ptr; 188 handle->_msg_ptr += rr->rdlength; 189 } 190 if (++handle->_rrnum > handle->_counts[(int)section]) 191 setsection(handle, (ns_sect)((int)section + 1)); 192 193 /* All done. */ 194 return (0); 195} 196 197/* Private. */ 198 199static void 200setsection(ns_msg *msg, ns_sect sect) { 201 msg->_sect = sect; 202 if (sect == ns_s_max) { 203 msg->_rrnum = -1; 204 msg->_msg_ptr = NULL; 205 } else { 206 msg->_rrnum = 0; 207 msg->_msg_ptr = msg->_sections[(int)sect]; 208 } 209} 210 211/*! \file */ 212