1 /* $NetBSD: ns_parse.c,v 1.2 2004/05/20 20:35:05 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 1.3.2.1.4.1 2004/03/09 08:33:44 marka Exp"; 24 #else 25 __RCSID("$NetBSD: ns_parse.c,v 1.2 2004/05/20 20:35:05 christos Exp $"); 26 #endif 27 #endif 28 29 /* Import. */ 30 31 #include <sys/types.h> 32 33 #include <netinet/in.h> 34 #include "arpa_nameser.h" 35 36 #include <errno.h> 37 #ifdef ANDROID_CHANGES 38 #include "resolv_private.h" 39 #else 40 #include <resolv.h> 41 #endif 42 #include <string.h> 43 44 /* Forward. */ 45 46 static void setsection(ns_msg *msg, ns_sect sect); 47 48 /* Macros. */ 49 50 #define RETERR(err) do { errno = (err); return (-1); } while (/*NOTREACHED*//*CONSTCOND*/0) 51 52 /* Public. */ 53 54 /* These need to be in the same order as the nres.h:ns_flag enum. */ 55 const struct _ns_flagdata _ns_flagdata[16] = { 56 { 0x8000, 15 }, /* qr. */ 57 { 0x7800, 11 }, /* opcode. */ 58 { 0x0400, 10 }, /* aa. */ 59 { 0x0200, 9 }, /* tc. */ 60 { 0x0100, 8 }, /* rd. */ 61 { 0x0080, 7 }, /* ra. */ 62 { 0x0040, 6 }, /* z. */ 63 { 0x0020, 5 }, /* ad. */ 64 { 0x0010, 4 }, /* cd. */ 65 { 0x000f, 0 }, /* rcode. */ 66 { 0x0000, 0 }, /* expansion (1/6). */ 67 { 0x0000, 0 }, /* expansion (2/6). */ 68 { 0x0000, 0 }, /* expansion (3/6). */ 69 { 0x0000, 0 }, /* expansion (4/6). */ 70 { 0x0000, 0 }, /* expansion (5/6). */ 71 { 0x0000, 0 }, /* expansion (6/6). */ 72 }; 73 74 int ns_msg_getflag(ns_msg handle, int flag) { 75 return((u_int32_t)((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift); 76 } 77 78 int 79 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) { 80 const u_char *optr = ptr; 81 82 for (; count > 0; count--) { 83 int b, rdlength; 84 85 b = dn_skipname(ptr, eom); 86 if (b < 0) 87 RETERR(EMSGSIZE); 88 ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/; 89 if (section != ns_s_qd) { 90 if (ptr + NS_INT32SZ + NS_INT16SZ > eom) 91 RETERR(EMSGSIZE); 92 ptr += NS_INT32SZ/*TTL*/; 93 NS_GET16(rdlength, ptr); 94 ptr += rdlength/*RData*/; 95 } 96 } 97 if (ptr > eom) 98 RETERR(EMSGSIZE); 99 return (ptr - optr); 100 } 101 102 int 103 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) { 104 const u_char *eom = msg + msglen; 105 int i; 106 107 memset(handle, 0x5e, sizeof *handle); 108 handle->_msg = msg; 109 handle->_eom = eom; 110 if (msg + NS_INT16SZ > eom) 111 RETERR(EMSGSIZE); 112 NS_GET16(handle->_id, msg); 113 if (msg + NS_INT16SZ > eom) 114 RETERR(EMSGSIZE); 115 NS_GET16(handle->_flags, msg); 116 for (i = 0; i < ns_s_max; i++) { 117 if (msg + NS_INT16SZ > eom) 118 RETERR(EMSGSIZE); 119 NS_GET16(handle->_counts[i], msg); 120 } 121 for (i = 0; i < ns_s_max; i++) 122 if (handle->_counts[i] == 0) 123 handle->_sections[i] = NULL; 124 else { 125 int b = ns_skiprr(msg, eom, (ns_sect)i, 126 handle->_counts[i]); 127 128 if (b < 0) 129 return (-1); 130 handle->_sections[i] = msg; 131 msg += b; 132 } 133 if (msg != eom) 134 RETERR(EMSGSIZE); 135 setsection(handle, ns_s_max); 136 return (0); 137 } 138 139 int 140 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) { 141 int b; 142 143 /* Make section right. */ 144 if ((unsigned)section >= (unsigned)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. */ 198 199 static void 200 setsection(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
