ns_parse.c revision 170242
1156952Sume/* 2156952Sume * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 3156952Sume * Copyright (c) 1996,1999 by Internet Software Consortium. 4156952Sume * 5156952Sume * Permission to use, copy, modify, and distribute this software for any 6156952Sume * purpose with or without fee is hereby granted, provided that the above 7156952Sume * copyright notice and this permission notice appear in all copies. 8156952Sume * 9156952Sume * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 10156952Sume * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11156952Sume * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 12156952Sume * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13156952Sume * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14156952Sume * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 15156952Sume * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16156952Sume */ 17156952Sume 18156952Sume#ifndef lint 19170242Sumestatic const char rcsid[] = "$Id: ns_parse.c,v 1.5.18.3 2005/10/11 00:25:10 marka Exp $"; 20156952Sume#endif 21156952Sume 22156952Sume/* Import. */ 23156952Sume 24156952Sume#include "port_before.h" 25156952Sume 26156952Sume#include <sys/types.h> 27156952Sume 28156952Sume#include <netinet/in.h> 29156952Sume#include <arpa/nameser.h> 30156952Sume 31156952Sume#include <errno.h> 32156952Sume#include <resolv.h> 33156952Sume#include <string.h> 34156952Sume 35156952Sume#include "port_after.h" 36156952Sume 37156952Sume/* Forward. */ 38156952Sume 39156952Sumestatic void setsection(ns_msg *msg, ns_sect sect); 40156952Sume 41156952Sume/* Macros. */ 42156952Sume 43156952Sume#ifndef SOLARIS2 44156952Sume#define RETERR(err) do { errno = (err); return (-1); } while (0) 45156952Sume#else 46156952Sume#define RETERR(err) \ 47156952Sume do { errno = (err); if (errno == errno) return (-1); } while (0) 48156952Sume#endif 49156952Sume 50156952Sume/* Public. */ 51156952Sume 52156952Sume/* These need to be in the same order as the nres.h:ns_flag enum. */ 53156952Sumestruct _ns_flagdata _ns_flagdata[16] = { 54170242Sume { 0x8000, 15 }, /*%< qr. */ 55170242Sume { 0x7800, 11 }, /*%< opcode. */ 56170242Sume { 0x0400, 10 }, /*%< aa. */ 57170242Sume { 0x0200, 9 }, /*%< tc. */ 58170242Sume { 0x0100, 8 }, /*%< rd. */ 59170242Sume { 0x0080, 7 }, /*%< ra. */ 60170242Sume { 0x0040, 6 }, /*%< z. */ 61170242Sume { 0x0020, 5 }, /*%< ad. */ 62170242Sume { 0x0010, 4 }, /*%< cd. */ 63170242Sume { 0x000f, 0 }, /*%< rcode. */ 64170242Sume { 0x0000, 0 }, /*%< expansion (1/6). */ 65170242Sume { 0x0000, 0 }, /*%< expansion (2/6). */ 66170242Sume { 0x0000, 0 }, /*%< expansion (3/6). */ 67170242Sume { 0x0000, 0 }, /*%< expansion (4/6). */ 68170242Sume { 0x0000, 0 }, /*%< expansion (5/6). */ 69170242Sume { 0x0000, 0 }, /*%< expansion (6/6). */ 70156952Sume}; 71156952Sume 72156952Sumeint ns_msg_getflag(ns_msg handle, int flag) { 73156952Sume return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); 74156952Sume} 75156952Sume 76156952Sumeint 77156952Sumens_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { 78156952Sume const u_char *optr = ptr; 79156952Sume 80156952Sume for ((void)NULL; count > 0; count--) { 81156952Sume int b, rdlength; 82156952Sume 83156952Sume b = dn_skipname(ptr, eom); 84156952Sume if (b < 0) 85156952Sume RETERR(EMSGSIZE); 86156952Sume ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; 87156952Sume if (section != ns_s_qd) { 88156952Sume if (ptr + NS_INT32SZ + NS_INT16SZ > eom) 89156952Sume RETERR(EMSGSIZE); 90156952Sume ptr += NS_INT32SZ/*TTL*/; 91156952Sume NS_GET16(rdlength, ptr); 92156952Sume ptr += rdlength/*RData*/; 93156952Sume } 94156952Sume } 95156952Sume if (ptr > eom) 96156952Sume RETERR(EMSGSIZE); 97156952Sume return (ptr - optr); 98156952Sume} 99156952Sume 100156952Sumeint 101156952Sumens_initparse(const u_char *msg, int msglen, ns_msg *handle) { 102156952Sume const u_char *eom = msg + msglen; 103156952Sume int i; 104156952Sume 105156952Sume memset(handle, 0x5e, sizeof *handle); 106156952Sume handle->_msg = msg; 107156952Sume handle->_eom = eom; 108156952Sume if (msg + NS_INT16SZ > eom) 109156952Sume RETERR(EMSGSIZE); 110156952Sume NS_GET16(handle->_id, msg); 111156952Sume if (msg + NS_INT16SZ > eom) 112156952Sume RETERR(EMSGSIZE); 113156952Sume NS_GET16(handle->_flags, msg); 114156952Sume for (i = 0; i < ns_s_max; i++) { 115156952Sume if (msg + NS_INT16SZ > eom) 116156952Sume RETERR(EMSGSIZE); 117156952Sume NS_GET16(handle->_counts[i], msg); 118156952Sume } 119156952Sume for (i = 0; i < ns_s_max; i++) 120156952Sume if (handle->_counts[i] == 0) 121156952Sume handle->_sections[i] = NULL; 122156952Sume else { 123156952Sume int b = ns_skiprr(msg, eom, (ns_sect)i, 124156952Sume handle->_counts[i]); 125156952Sume 126156952Sume if (b < 0) 127156952Sume return (-1); 128156952Sume handle->_sections[i] = msg; 129156952Sume msg += b; 130156952Sume } 131156952Sume if (msg != eom) 132156952Sume RETERR(EMSGSIZE); 133156952Sume setsection(handle, ns_s_max); 134156952Sume return (0); 135156952Sume} 136156952Sume 137156952Sumeint 138156952Sumens_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { 139156952Sume int b; 140156952Sume int tmp; 141156952Sume 142156952Sume /* Make section right. */ 143156952Sume tmp = section; 144156952Sume if (tmp < 0 || section >= ns_s_max) 145156952Sume RETERR(ENODEV); 146156952Sume if (section != handle->_sect) 147156952Sume setsection(handle, section); 148156952Sume 149156952Sume /* Make rrnum right. */ 150156952Sume if (rrnum == -1) 151156952Sume rrnum = handle->_rrnum; 152156952Sume if (rrnum < 0 || rrnum >= handle->_counts[(int)section]) 153156952Sume RETERR(ENODEV); 154156952Sume if (rrnum < handle->_rrnum) 155156952Sume setsection(handle, section); 156156952Sume if (rrnum > handle->_rrnum) { 157156952Sume b = ns_skiprr(handle->_msg_ptr, handle->_eom, section, 158156952Sume rrnum - handle->_rrnum); 159156952Sume 160156952Sume if (b < 0) 161156952Sume return (-1); 162156952Sume handle->_msg_ptr += b; 163156952Sume handle->_rrnum = rrnum; 164156952Sume } 165156952Sume 166156952Sume /* Do the parse. */ 167156952Sume b = dn_expand(handle->_msg, handle->_eom, 168156952Sume handle->_msg_ptr, rr->name, NS_MAXDNAME); 169156952Sume if (b < 0) 170156952Sume return (-1); 171156952Sume handle->_msg_ptr += b; 172156952Sume if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) 173156952Sume RETERR(EMSGSIZE); 174156952Sume NS_GET16(rr->type, handle->_msg_ptr); 175156952Sume NS_GET16(rr->rr_class, handle->_msg_ptr); 176156952Sume if (section == ns_s_qd) { 177156952Sume rr->ttl = 0; 178156952Sume rr->rdlength = 0; 179156952Sume rr->rdata = NULL; 180156952Sume } else { 181156952Sume if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) 182156952Sume RETERR(EMSGSIZE); 183156952Sume NS_GET32(rr->ttl, handle->_msg_ptr); 184156952Sume NS_GET16(rr->rdlength, handle->_msg_ptr); 185156952Sume if (handle->_msg_ptr + rr->rdlength > handle->_eom) 186156952Sume RETERR(EMSGSIZE); 187156952Sume rr->rdata = handle->_msg_ptr; 188156952Sume handle->_msg_ptr += rr->rdlength; 189156952Sume } 190156952Sume if (++handle->_rrnum > handle->_counts[(int)section]) 191156952Sume setsection(handle, (ns_sect)((int)section + 1)); 192156952Sume 193156952Sume /* All done. */ 194156952Sume return (0); 195156952Sume} 196156952Sume 197156952Sume/* Private. */ 198156952Sume 199156952Sumestatic void 200156952Sumesetsection(ns_msg *msg, ns_sect sect) { 201156952Sume msg->_sect = sect; 202156952Sume if (sect == ns_s_max) { 203156952Sume msg->_rrnum = -1; 204156952Sume msg->_msg_ptr = NULL; 205156952Sume } else { 206156952Sume msg->_rrnum = 0; 207156952Sume msg->_msg_ptr = msg->_sections[(int)sect]; 208156952Sume } 209156952Sume} 210170242Sume 211170242Sume/*! \file */ 212