1 /* $NetBSD: ns_parse.c,v 1.6 2008/06/21 20:41:48 christos Exp $ */ 2 3 /* 4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 5 * Copyright (c) 1996,1999 by Internet Software Consortium. 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 17 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include <sys/cdefs.h> 21 #ifndef lint 22 #ifdef notdef 23 static const char rcsid[] = "Id: ns_parse.c,v 1.9 2007/08/27 03:32:26 marka Exp"; 24 #else 25 __RCSID("$NetBSD: ns_parse.c,v 1.6 2008/06/21 20:41:48 christos Exp $"); 26 #endif 27 #endif 28 29 /* Import. */ 30 31 #include "port_before.h" 32 33 #include <sys/types.h> 34 35 #include <netinet/in.h> 36 #include <arpa/nameser.h> 37 38 #include <errno.h> 39 #include <resolv.h> 40 #include <string.h> 41 42 #include "port_after.h" 43 44 /* Forward. */ 45 46 static void setsection(ns_msg *msg, ns_sect sect); 47 48 /* Macros. */ 49 50 #if !defined(SOLARIS2) || defined(__COVERITY__) 51 #define RETERR(err) do { errno = (err); return (-1); } while (/*NOTREACHED*//*CONSTCOND*/0) 52 #else 53 #define RETERR(err) \ 54 do { errno = (err); if (errno == errno) return (-1); } while (0) 55 #endif 56 57 /* Public. */ 58 59 /* These need to be in the same order as the nres.h:ns_flag enum. */ 60 struct _ns_flagdata _ns_flagdata[16] = { 61 { 0x8000, 15 }, /*%< qr. */ 62 { 0x7800, 11 }, /*%< opcode. */ 63 { 0x0400, 10 }, /*%< aa. */ 64 { 0x0200, 9 }, /*%< tc. */ 65 { 0x0100, 8 }, /*%< rd. */ 66 { 0x0080, 7 }, /*%< ra. */ 67 { 0x0040, 6 }, /*%< z. */ 68 { 0x0020, 5 }, /*%< ad. */ 69 { 0x0010, 4 }, /*%< cd. */ 70 { 0x000f, 0 }, /*%< rcode. */ 71 { 0x0000, 0 }, /*%< expansion (1/6). */ 72 { 0x0000, 0 }, /*%< expansion (2/6). */ 73 { 0x0000, 0 }, /*%< expansion (3/6). */ 74 { 0x0000, 0 }, /*%< expansion (4/6). */ 75 { 0x0000, 0 }, /*%< expansion (5/6). */ 76 { 0x0000, 0 }, /*%< expansion (6/6). */ 77 }; 78 79 int ns_msg_getflag(ns_msg handle, int flag) { 80 return((u_int32_t)((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); 81 } 82 83 int 84 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { 85 const u_char *optr = ptr; 86 87 for (; count > 0; count--) { 88 int b, rdlength; 89 90 b = dn_skipname(ptr, eom); 91 if (b < 0) 92 RETERR(EMSGSIZE); 93 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; 94 if (section != ns_s_qd) { 95 if (ptr + NS_INT32SZ + NS_INT16SZ > eom) 96 RETERR(EMSGSIZE); 97 ptr += NS_INT32SZ/*TTL*/; 98 NS_GET16(rdlength, ptr); 99 ptr += rdlength/*RData*/; 100 } 101 } 102 if (ptr > eom) 103 RETERR(EMSGSIZE); 104 return (ptr - optr); 105 } 106 107 int 108 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) { 109 const u_char *eom = msg + msglen; 110 int i; 111 112 memset(handle, 0x5e, sizeof *handle); 113 handle->_msg = msg; 114 handle->_eom = eom; 115 if (msg + NS_INT16SZ > eom) 116 RETERR(EMSGSIZE); 117 NS_GET16(handle->_id, msg); 118 if (msg + NS_INT16SZ > eom) 119 RETERR(EMSGSIZE); 120 NS_GET16(handle->_flags, msg); 121 for (i = 0; i < ns_s_max; i++) { 122 if (msg + NS_INT16SZ > eom) 123 RETERR(EMSGSIZE); 124 NS_GET16(handle->_counts[i], msg); 125 } 126 for (i = 0; i < ns_s_max; i++) 127 if (handle->_counts[i] == 0) 128 handle->_sections[i] = NULL; 129 else { 130 int b = ns_skiprr(msg, eom, (ns_sect)i, 131 handle->_counts[i]); 132 133 if (b < 0) 134 return (-1); 135 handle->_sections[i] = msg; 136 msg += b; 137 } 138 if (msg != eom) 139 RETERR(EMSGSIZE); 140 setsection(handle, ns_s_max); 141 return (0); 142 } 143 144 int 145 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { 146 int b; 147 int tmp; 148 149 /* Make section right. */ 150 tmp = section; 151 if (tmp < 0 || section >= ns_s_max) 152 RETERR(ENODEV); 153 if (section != handle->_sect) 154 setsection(handle, section); 155 156 /* Make rrnum right. */ 157 if (rrnum == -1) 158 rrnum = handle->_rrnum; 159 if (rrnum < 0 || rrnum >= handle->_counts[(int)section]) 160 RETERR(ENODEV); 161 if (rrnum < handle->_rrnum) 162 setsection(handle, section); 163 if (rrnum > handle->_rrnum) { 164 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section, 165 rrnum - handle->_rrnum); 166 167 if (b < 0) 168 return (-1); 169 handle->_msg_ptr += b; 170 handle->_rrnum = rrnum; 171 } 172 173 /* Do the parse. */ 174 b = dn_expand(handle->_msg, handle->_eom, 175 handle->_msg_ptr, rr->name, NS_MAXDNAME); 176 if (b < 0) 177 return (-1); 178 handle->_msg_ptr += b; 179 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) 180 RETERR(EMSGSIZE); 181 NS_GET16(rr->type, handle->_msg_ptr); 182 NS_GET16(rr->rr_class, handle->_msg_ptr); 183 if (section == ns_s_qd) { 184 rr->ttl = 0; 185 rr->rdlength = 0; 186 rr->rdata = NULL; 187 } else { 188 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) 189 RETERR(EMSGSIZE); 190 NS_GET32(rr->ttl, handle->_msg_ptr); 191 NS_GET16(rr->rdlength, handle->_msg_ptr); 192 if (handle->_msg_ptr + rr->rdlength > handle->_eom) 193 RETERR(EMSGSIZE); 194 rr->rdata = handle->_msg_ptr; 195 handle->_msg_ptr += rr->rdlength; 196 } 197 if (++handle->_rrnum > handle->_counts[(int)section]) 198 setsection(handle, (ns_sect)((int)section + 1)); 199 200 /* All done. */ 201 return (0); 202 } 203 204 /* Private. */ 205 206 static void 207 setsection(ns_msg *msg, ns_sect sect) { 208 msg->_sect = sect; 209 if (sect == ns_s_max) { 210 msg->_rrnum = -1; 211 msg->_msg_ptr = NULL; 212 } else { 213 msg->_rrnum = 0; 214 msg->_msg_ptr = msg->_sections[(int)sect]; 215 } 216 } 217 218 /*! \file */ 219