1 /* 2 * Copyright 2005 Niels Provos <provos@citi.umich.edu> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Niels Provos. 16 * 4. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 /* 32 * ++Copyright++ 1983, 1989, 1993 33 * - 34 * Copyright (c) 1983, 1989, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 3. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * - 61 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 62 * 63 * Permission to use, copy, modify, and distribute this software for any 64 * purpose with or without fee is hereby granted, provided that the above 65 * copyright notice and this permission notice appear in all copies, and that 66 * the name of Digital Equipment Corporation not be used in advertising or 67 * publicity pertaining to distribution of the document or software without 68 * specific, written prior permission. 69 * 70 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 71 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 72 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 73 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 74 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 75 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 76 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 77 * SOFTWARE. 78 * - 79 * Portions Copyright (c) 1995 by International Business Machines, Inc. 80 * 81 * International Business Machines, Inc. (hereinafter called IBM) grants 82 * permission under its copyrights to use, copy, modify, and distribute this 83 * Software with or without fee, provided that the above copyright notice and 84 * all paragraphs of this notice appear in all copies, and that the name of IBM 85 * not be used in connection with the marketing of any product incorporating 86 * the Software or modifications thereof, without specific, written prior 87 * permission. 88 * 89 * To the extent it has a right to do so, IBM grants an immunity from suit 90 * under its patents, if any, for the use, sale or manufacture of products to 91 * the extent that such products are used for performing Domain Name System 92 * dynamic updates in TCP/IP networks by means of the Software. No immunity is 93 * granted for any product per se or for any other function of any product. 94 * 95 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES, 96 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 97 * PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL, 98 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING 99 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN 100 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES. 101 * --Copyright-- 102 */ 103 104 #ifndef _DNSRES_INTERNAL_H_ 105 #define _DNSRES_INTERNAL_H_ 106 107 /* 108 * Define constants based on rfc883 109 */ 110 #define DNSRES_PACKETSZ 512 /* maximum packet size */ 111 #define DNSRES_MAXDNAME 1025 /* maximum presentation domain name */ 112 #define DNSRES_MAXCDNAME 255 /* maximum compressed domain name */ 113 #define DNSRES_MAXLABEL 63 /* maximum length of domain label */ 114 #define DNSRES_HFIXEDSZ 12 /* #/bytes of fixed data in header */ 115 #define DNSRES_QFIXEDSZ 4 /* #/bytes of fixed data in query */ 116 #define DNSRES_RRFIXEDSZ 10 /* #/bytes of fixed data in r record */ 117 #define DNSRES_INT32SZ 4 /* for systems without 32-bit ints */ 118 #define DNSRES_INT16SZ 2 /* for systems without 16-bit ints */ 119 #define DNSRES_INADDRSZ 4 /* IPv4 T_A */ 120 #define DNSRES_IN6ADDRSZ 16 /* IPv6 T_AAAA */ 121 122 #define MAXPACKET (64*1024) 123 124 /* 125 * Structure for query header. The order of the fields is machine- and 126 * compiler-dependent, depending on the byte/bit order and the layout 127 * of bit fields. We use bit fields only in int variables, as this 128 * is all ANSI requires. This requires a somewhat confusing rearrangement. 129 */ 130 131 typedef struct { 132 unsigned id :16; /* query identification number */ 133 #ifdef HAVE_BIG_ENDIAN 134 /* fields in third byte */ 135 unsigned qr: 1; /* response flag */ 136 unsigned opcode: 4; /* purpose of message */ 137 unsigned aa: 1; /* authoritive answer */ 138 unsigned tc: 1; /* truncated message */ 139 unsigned rd: 1; /* recursion desired */ 140 /* fields in fourth byte */ 141 unsigned ra: 1; /* recursion available */ 142 unsigned unused :1; /* unused bits (MBZ as of 4.9.3a3) */ 143 unsigned ad: 1; /* authentic data from named */ 144 unsigned cd: 1; /* checking disabled by resolver */ 145 unsigned rcode :4; /* response code */ 146 #else /* !HAVE_BIG_ENDIAN - for our little endians */ 147 /* fields in third byte */ 148 unsigned rd :1; /* recursion desired */ 149 unsigned tc :1; /* truncated message */ 150 unsigned aa :1; /* authoritive answer */ 151 unsigned opcode :4; /* purpose of message */ 152 unsigned qr :1; /* response flag */ 153 /* fields in fourth byte */ 154 unsigned rcode :4; /* response code */ 155 unsigned cd: 1; /* checking disabled by resolver */ 156 unsigned ad: 1; /* authentic data from named */ 157 unsigned unused :1; /* unused bits (MBZ as of 4.9.3a3) */ 158 unsigned ra :1; /* recursion available */ 159 #endif 160 /* remaining bytes */ 161 unsigned qdcount :16; /* number of question entries */ 162 unsigned ancount :16; /* number of answer entries */ 163 unsigned nscount :16; /* number of authority entries */ 164 unsigned arcount :16; /* number of resource entries */ 165 } DNSRES_HEADER; 166 167 typedef union { 168 DNSRES_HEADER hdr; 169 u_char buf[MAXPACKET]; 170 } querybuf; 171 172 struct dnsres_socket { 173 struct event ev; 174 struct sockaddr *nsap; 175 socklen_t salen; 176 177 int s; /* socket used for communications */ 178 int connected; /* is the socket connected */ 179 int vc; /* is the socket a virtual ciruit? */ 180 int af; /* address family of socket */ 181 }; 182 183 struct dnsres_target { 184 struct dnsres_target *next; 185 const char *name; /* domain name */ 186 int qclass, qtype; /* class and type of query */ 187 u_char *answer; /* buffer to put answer */ 188 int anslen; /* size of answer buffer */ 189 int n; /* result length */ 190 }; 191 192 #define MULTI_PTRS_ARE_ALIASES 1 /* XXX - experimental */ 193 194 #define MAXALIASES 35 195 #define MAXADDRS 35 196 197 /* state used by all the gethostby* functions */ 198 199 struct dnsres_cbstate { 200 void (*cb)(struct dnsres_hostent *hp, int dr_errno, void *arg); 201 void *cb_arg; 202 203 struct dnsres_hostent *hp; 204 char *name; /* the name we are trying to resolve */ 205 size_t name_len; 206 207 int af; 208 struct dnsres *_resp; 209 210 char lookups[MAXDNSLUS]; 211 int lookup_index; 212 struct dnsres_target q; 213 int size; 214 querybuf *buf; 215 char qbuf[MAXDNAME+1]; 216 217 void (*internal_cb)(struct dnsres_hostent *, struct dnsres_cbstate *); 218 219 /* More resolver state to carry around */ 220 char *h_addr_ptrs[MAXADDRS + 1]; 221 222 struct dnsres_hostent host; 223 char *host_aliases[MAXALIASES]; 224 char hostbuf[BUFSIZ+1]; 225 union { 226 struct in_addr _host_in_addr; 227 u_char _host_addr[16]; /* IPv4 or IPv6 */ 228 } _host_addr_u; 229 #define host_addr _host_addr_u._host_addr 230 }; 231 232 /* state used by all the res functions */ 233 234 #if PACKETSZ > 1024 235 #define UDP_MAXPACKET PACKETSZ 236 #else 237 #define UDP_MAXPACKET 1024 238 #endif 239 240 struct res_search_state { 241 struct dnsres *_resp; 242 243 const char *name; 244 struct dnsres_target *target; 245 int ancount; /* used when we have multiple queries */ 246 247 void (*cb)(int, void *); 248 void *cb_arg; 249 250 void (*res_conditional_cb)(struct res_search_state *); 251 252 int trailing_dot; 253 u_int dots; 254 int tried_as_is; 255 int saved_herrno; 256 int dont_save_errno; 257 int done; 258 int got_nodata; 259 int got_servfail; 260 261 const char * const *domain; 262 263 /* res_query state */ 264 u_char buf[UDP_MAXPACKET]; 265 266 /* res_send state */ 267 struct dnsres_socket ds; /* XXX - move away */ 268 269 void (*send_cb)(int, struct res_search_state *); 270 const u_char *send_buf; 271 int resplen; 272 int send_buflen; 273 int gotsomewhere; 274 int terrno; 275 int v_circuit; 276 int try; 277 int connreset; 278 u_int badns; /* XXX NSMAX can't exceed #/bits in this var */ 279 int ns; 280 int ret; 281 282 int read_len; /* used by res_send_vcircuit magic */ 283 int truncated; 284 u_char *cp; 285 }; 286 287 /* 288 * Encapsulates the query state, so that it can be passed around between 289 * functions. 290 */ 291 struct dnsres_cbstate *dnsres_cbstate_new( 292 struct dnsres *_resp, const char *name, size_t len, 293 void (*cb)(struct dnsres_hostent *, int, void *), void *arg); 294 295 /* 296 * Defines for handling compressed domain names 297 */ 298 #define DNSRES_INDIR_MASK 0xc0 299 300 /* 301 * Inline versions of get/put short/long. Pointer is advanced. 302 * 303 * These macros demonstrate the property of C whereby it can be 304 * portable or it can be elegant but rarely both. 305 */ 306 #define DNSRES_GETSHORT(s, cp) { \ 307 unsigned char *t_cp = (unsigned char *)(cp); \ 308 (s) = ((u_int16_t)t_cp[0] << 8) \ 309 | ((u_int16_t)t_cp[1]) \ 310 ; \ 311 (cp) += INT16SZ; \ 312 } 313 314 #define DNSRES_GETLONG(l, cp) { \ 315 unsigned char *t_cp = (unsigned char *)(cp); \ 316 (l) = ((u_int32_t)t_cp[0] << 24) \ 317 | ((u_int32_t)t_cp[1] << 16) \ 318 | ((u_int32_t)t_cp[2] << 8) \ 319 | ((u_int32_t)t_cp[3]) \ 320 ; \ 321 (cp) += INT32SZ; \ 322 } 323 324 #define DNSRES_PUTSHORT(s, cp) { \ 325 u_int16_t t_s = (u_int16_t)(s); \ 326 unsigned char *t_cp = (unsigned char *)(cp); \ 327 *t_cp++ = t_s >> 8; \ 328 *t_cp = t_s; \ 329 (cp) += INT16SZ; \ 330 } 331 332 #define DNSRES_PUTLONG(l, cp) { \ 333 u_int32_t t_l = (u_int32_t)(l); \ 334 unsigned char *t_cp = (unsigned char *)(cp); \ 335 *t_cp++ = t_l >> 24; \ 336 *t_cp++ = t_l >> 16; \ 337 *t_cp++ = t_l >> 8; \ 338 *t_cp = t_l; \ 339 (cp) += INT32SZ; \ 340 } 341 342 #endif /* _DNSRES_INTERNAL_H_ */ 343