ns_parse.c revision 1.1.1.1
1 /* $NetBSD: ns_parse.c,v 1.1.1.1 2004/05/20 20:01:31 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 #ifndef lint 21 static const char rcsid[] = "Id: ns_parse.c,v 1.3.2.1.4.1 2004/03/09 08:33:44 marka Exp"; 22 #endif 23 24 /* Import. */ 25 26 #include "port_before.h" 27 28 #include <sys/types.h> 29 30 #include <netinet/in.h> 31 #include <arpa/nameser.h> 32 33 #include <errno.h> 34 #include <resolv.h> 35 #include <string.h> 36 37 #include "port_after.h" 38 39 /* Forward. */ 40 41 static void setsection(ns_msg *msg, ns_sect sect); 42 43 /* Macros. */ 44 45 #define RETERR(err) do { errno = (err); return (-1); } while (0) 46 47 /* Public. */ 48 49 /* These need to be in the same order as the nres.h:ns_flag enum. */ 50 struct _ns_flagdata _ns_flagdata[16] = { 51 { 0x8000, 15 }, /* qr. */ 52 { 0x7800, 11 }, /* opcode. */ 53 { 0x0400, 10 }, /* aa. */ 54 { 0x0200, 9 }, /* tc. */ 55 { 0x0100, 8 }, /* rd. */ 56 { 0x0080, 7 }, /* ra. */ 57 { 0x0040, 6 }, /* z. */ 58 { 0x0020, 5 }, /* ad. */ 59 { 0x0010, 4 }, /* cd. */ 60 { 0x000f, 0 }, /* rcode. */ 61 { 0x0000, 0 }, /* expansion (1/6). */ 62 { 0x0000, 0 }, /* expansion (2/6). */ 63 { 0x0000, 0 }, /* expansion (3/6). */ 64 { 0x0000, 0 }, /* expansion (4/6). */ 65 { 0x0000, 0 }, /* expansion (5/6). */ 66 { 0x0000, 0 }, /* expansion (6/6). */ 67 }; 68 69 int ns_msg_getflag(ns_msg handle, int flag) { 70 return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); 71 } 72 73 int 74 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { 75 const u_char *optr = ptr; 76 77 for ((void)NULL; count > 0; count--) { 78 int b, rdlength; 79 80 b = dn_skipname(ptr, eom); 81 if (b < 0) 82 RETERR(EMSGSIZE); 83 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; 84 if (section != ns_s_qd) { 85 if (ptr + NS_INT32SZ + NS_INT16SZ > eom) 86 RETERR(EMSGSIZE); 87 ptr += NS_INT32SZ/*TTL*/; 88 NS_GET16(rdlength, ptr); 89 ptr += rdlength/*RData*/; 90 } 91 } 92 if (ptr > eom) 93 RETERR(EMSGSIZE); 94 return (ptr - optr); 95 } 96 97 int 98 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) { 99 const u_char *eom = msg + msglen; 100 int i; 101 102 memset(handle, 0x5e, sizeof *handle); 103 handle->_msg = msg; 104 handle->_eom = eom; 105 if (msg + NS_INT16SZ > eom) 106 RETERR(EMSGSIZE); 107 NS_GET16(handle->_id, msg); 108 if (msg + NS_INT16SZ > eom) 109 RETERR(EMSGSIZE); 110 NS_GET16(handle->_flags, msg); 111 for (i = 0; i < ns_s_max; i++) { 112 if (msg + NS_INT16SZ > eom) 113 RETERR(EMSGSIZE); 114 NS_GET16(handle->_counts[i], msg); 115 } 116 for (i = 0; i < ns_s_max; i++) 117 if (handle->_counts[i] == 0) 118 handle->_sections[i] = NULL; 119 else { 120 int b = ns_skiprr(msg, eom, (ns_sect)i, 121 handle->_counts[i]); 122 123 if (b < 0) 124 return (-1); 125 handle->_sections[i] = msg; 126 msg += b; 127 } 128 if (msg != eom) 129 RETERR(EMSGSIZE); 130 setsection(handle, ns_s_max); 131 return (0); 132 } 133 134 int 135 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { 136 int b; 137 int tmp; 138 139 /* Make section right. */ 140 if ((tmp = section) < 0 || section >= ns_s_max) 141 RETERR(ENODEV); 142 if (section != handle->_sect) 143 setsection(handle, section); 144 145 /* Make rrnum right. */ 146 if (rrnum == -1) 147 rrnum = handle->_rrnum; 148 if (rrnum < 0 || rrnum >= handle->_counts[(int)section]) 149 RETERR(ENODEV); 150 if (rrnum < handle->_rrnum) 151 setsection(handle, section); 152 if (rrnum > handle->_rrnum) { 153 b = ns_skiprr(handle->_msg_ptr, handle->_eom, section, 154 rrnum - handle->_rrnum); 155 156 if (b < 0) 157 return (-1); 158 handle->_msg_ptr += b; 159 handle->_rrnum = rrnum; 160 } 161 162 /* Do the parse. */ 163 b = dn_expand(handle->_msg, handle->_eom, 164 handle->_msg_ptr, rr->name, NS_MAXDNAME); 165 if (b < 0) 166 return (-1); 167 handle->_msg_ptr += b; 168 if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom) 169 RETERR(EMSGSIZE); 170 NS_GET16(rr->type, handle->_msg_ptr); 171 NS_GET16(rr->rr_class, handle->_msg_ptr); 172 if (section == ns_s_qd) { 173 rr->ttl = 0; 174 rr->rdlength = 0; 175 rr->rdata = NULL; 176 } else { 177 if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom) 178 RETERR(EMSGSIZE); 179 NS_GET32(rr->ttl, handle->_msg_ptr); 180 NS_GET16(rr->rdlength, handle->_msg_ptr); 181 if (handle->_msg_ptr + rr->rdlength > handle->_eom) 182 RETERR(EMSGSIZE); 183 rr->rdata = handle->_msg_ptr; 184 handle->_msg_ptr += rr->rdlength; 185 } 186 if (++handle->_rrnum > handle->_counts[(int)section]) 187 setsection(handle, (ns_sect)((int)section + 1)); 188 189 /* All done. */ 190 return (0); 191 } 192 193 /* Private. */ 194 195 static void 196 setsection(ns_msg *msg, ns_sect sect) { 197 msg->_sect = sect; 198 if (sect == ns_s_max) { 199 msg->_rrnum = -1; 200 msg->_msg_ptr = NULL; 201 } else { 202 msg->_rrnum = 0; 203 msg->_msg_ptr = msg->_sections[(int)sect]; 204 } 205 } 206
Indexes created Tue Sep 30 20:09:53 GMT 2025