| 1 | /* |
| 2 | * internal.h |
| 3 | * - declarations of private objects with external linkage (adns__*) |
| 4 | * - definitons of internal macros |
| 5 | * - comments regarding library data structures |
| 6 | */ |
| 7 | /* |
| 8 | * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2, or (at your option) |
| 13 | * any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License |
| 21 | * along with this program; if not, write to the Free Software Foundation, |
| 22 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 23 | */ |
| 24 | |
| 25 | #ifndef ADNS_INTERNAL_H_INCLUDED |
| 26 | #define ADNS_INTERNAL_H_INCLUDED |
| 27 | |
| 28 | #define PRINTFFORMAT(a,b) __attribute__((format(printf,a,b))) |
| 29 | typedef unsigned char byte; |
| 30 | |
| 31 | #include <stdarg.h> |
| 32 | #include <assert.h> |
| 33 | #include <unistd.h> |
| 34 | |
| 35 | #include <sys/time.h> |
| 36 | |
| 37 | #include "adns.h" |
| 38 | |
| 39 | /* Configuration and constants */ |
| 40 | |
| 41 | #define MAXSERVERS 5 |
| 42 | #define UDPMAXRETRIES /*15*/5 |
| 43 | #define UDPRETRYMS 2000 |
| 44 | #define TCPMS 30000 |
| 45 | #define LOCALRESOURCEMS 20 |
| 46 | |
| 47 | #define DNS_PORT 53 |
| 48 | #define DNS_MAXUDP 512 |
| 49 | #define DNS_MAXDOMAIN 255 |
| 50 | #define DNS_HDRSIZE 12 |
| 51 | #define DNS_CLASS_IN 1 |
| 52 | |
| 53 | typedef enum { |
| 54 | rcode_noerror, |
| 55 | rcode_formaterror, |
| 56 | rcode_servfail, |
| 57 | rcode_nxdomain, |
| 58 | rcode_notimp, |
| 59 | rcode_refused |
| 60 | } dns_rcode; |
| 61 | |
| 62 | /* Shared data structures */ |
| 63 | |
| 64 | typedef union { |
| 65 | adns_status status; |
| 66 | char *cp; |
| 67 | adns_rrtype type; |
| 68 | int i; |
| 69 | struct in_addr ia; |
| 70 | unsigned long ul; |
| 71 | } rr_align; |
| 72 | |
| 73 | typedef struct { |
| 74 | int used, avail; |
| 75 | byte *buf; |
| 76 | } vbuf; |
| 77 | |
| 78 | typedef union { |
| 79 | void *ext; |
| 80 | int dmaddr_index; |
| 81 | } qcontext; |
| 82 | |
| 83 | typedef struct { |
| 84 | adns_rrtype type; |
| 85 | const char *rrtname; |
| 86 | const char *fmtname; |
| 87 | int rrsz; |
| 88 | |
| 89 | void (*makefinal)(adns_query qu, void *data); |
| 90 | /* Change memory management of *data. |
| 91 | * Previously, used alloc_interim, now use alloc_final. |
| 92 | */ |
| 93 | |
| 94 | adns_status (*convstring)(vbuf *vb, const void *data); |
| 95 | /* Converts the RR data to a string representation in vbuf. |
| 96 | * vbuf will be appended to (it must have been initialised), |
| 97 | * and will not be null-terminated by convstring. |
| 98 | */ |
| 99 | |
| 100 | adns_status (*parse)(adns_query qu, int serv, |
| 101 | const byte *dgram, int dglen, int cbyte, int max, |
| 102 | void *store_r); |
| 103 | /* Parse one RR, in dgram of length dglen, starting at cbyte and |
| 104 | * extending until at most max. |
| 105 | * |
| 106 | * The RR should be stored at *store_r, of length qu->typei->rrsz. |
| 107 | * |
| 108 | * If there is an overrun which might indicate truncation, it should set |
| 109 | * *rdstart to -1; otherwise it may set it to anything else positive. |
| 110 | */ |
| 111 | } typeinfo; |
| 112 | |
| 113 | typedef struct allocnode { |
| 114 | struct allocnode *next; |
| 115 | } allocnode; |
| 116 | |
| 117 | union maxalign { |
| 118 | byte d[1]; |
| 119 | struct in_addr ia; |
| 120 | long l; |
| 121 | void *p; |
| 122 | void (*fp)(void); |
| 123 | union maxalign *up; |
| 124 | } data; |
| 125 | |
| 126 | struct adns__query { |
| 127 | adns_state ads; |
| 128 | enum { query_udp, query_tcpwait, query_tcpsent, query_child, query_done } state; |
| 129 | adns_query back, next, parent; |
| 130 | struct { adns_query head, tail; } children; |
| 131 | struct { adns_query back, next; } siblings; |
| 132 | struct allocnode *allocations; |
| 133 | int interim_allocd; |
| 134 | void *final_allocspace; |
| 135 | |
| 136 | const typeinfo *typei; |
| 137 | char *query_dgram; |
| 138 | int query_dglen; |
| 139 | |
| 140 | vbuf vb; |
| 141 | /* General-purpose messing-about buffer. |
| 142 | * Wherever a `big' interface is crossed, this may be corrupted/changed |
| 143 | * unless otherwise specified. |
| 144 | */ |
| 145 | |
| 146 | adns_answer *answer; |
| 147 | /* This is allocated when a query is submitted, to avoid being unable |
| 148 | * to relate errors to queries if we run out of memory. During |
| 149 | * query processing status, rrs is 0. cname is set if |
| 150 | * we found a cname (this corresponds to cname_dgram in the query |
| 151 | * structure). type is set from the word go. nrrs and rrs |
| 152 | * are set together, when we find how many rrs there are. |
| 153 | */ |
| 154 | |
| 155 | byte *cname_dgram; |
| 156 | int cname_dglen, cname_begin; |
| 157 | /* If non-0, has been allocated using . */ |
| 158 | |
| 159 | int id, flags, udpretries; |
| 160 | int udpnextserver; |
| 161 | unsigned long udpsent, tcpfailed; /* bitmap indexed by server */ |
| 162 | struct timeval timeout; |
| 163 | qcontext context; |
| 164 | |
| 165 | /* Possible states: |
| 166 | * |
| 167 | * state Queue child id nextudpserver sentudp failedtcp |
| 168 | * |
| 169 | * udp NONE null >=0 0 zero zero |
| 170 | * udp timew null >=0 any nonzero zero |
| 171 | * udp NONE null >=0 any nonzero zero |
| 172 | * |
| 173 | * tcpwait timew null >=0 irrelevant zero any |
| 174 | * tcpsent timew null >=0 irrelevant zero any |
| 175 | * |
| 176 | * child childw set >=0 irrelevant irrelevant irrelevant |
| 177 | * done output null -1 irrelevant irrelevant irrelevant |
| 178 | * |
| 179 | * +------------------------+ |
| 180 | * START -----> | udp/NONE | |
| 181 | * +------------------------+ |
| 182 | * / |\ \ |
| 183 | * too big for UDP / UDP timeout \ \ send via UDP |
| 184 | * do this ASAP! / more retries \ \ do this ASAP! |
| 185 | * |_ desired \ _| |
| 186 | * +---------------+ +-----------+ |
| 187 | * | tcpwait/timew | ____ | udp/timew | |
| 188 | * +---------------+ \ +-----------+ |
| 189 | * | ^ | | | |
| 190 | * TCP conn'd; | | TCP died | | | |
| 191 | * send via TCP | | more | UDP timeout | | |
| 192 | * do this ASAP! | | servers | no more | | |
| 193 | * v | to try | retries | | |
| 194 | * +---------------+ | desired | | |
| 195 | * | tcpsent/timew | ____ | | | |
| 196 | * +---------------+ \| | | |
| 197 | * \ \ TCP died | TCP | | |
| 198 | * \ \ no more | timeout / | |
| 199 | * \ \ servers | / | |
| 200 | * \ \ to try | / | |
| 201 | * got \ \ v |_ / got |
| 202 | * reply \ _| +------------------+ / reply |
| 203 | * \ | done/output FAIL | / |
| 204 | * \ +------------------+ / |
| 205 | * \ / |
| 206 | * _| |_ |
| 207 | * (..... got reply ....) |
| 208 | * / \ |
| 209 | * need child query/ies / \ no child query |
| 210 | * / \ |
| 211 | * |_ _| |
| 212 | * +--------------+ +----------------+ |
| 213 | * | child/childw | ----------------> | done/output OK | |
| 214 | * +--------------+ children done +----------------+ |
| 215 | */ |
| 216 | }; |
| 217 | |
| 218 | struct adns__state { |
| 219 | adns_initflags iflags; |
| 220 | FILE *diagfile; |
| 221 | struct { adns_query head, tail; } timew, childw, output; |
| 222 | int nextid, udpsocket, tcpsocket; |
| 223 | vbuf tcpsend, tcprecv; |
| 224 | int nservers, tcpserver; |
| 225 | enum adns__tcpstate { server_disconnected, server_connecting, server_ok } tcpstate; |
| 226 | struct timeval tcptimeout; |
| 227 | struct server { |
| 228 | struct in_addr addr; |
| 229 | } servers[MAXSERVERS]; |
| 230 | }; |
| 231 | |
| 232 | /* From setup.c: */ |
| 233 | |
| 234 | int adns__setnonblock(adns_state ads, int fd); /* => errno value */ |
| 235 | |
| 236 | /* From general.c: */ |
| 237 | |
| 238 | void adns__vdiag(adns_state ads, const char *pfx, adns_initflags prevent, |
| 239 | int serv, adns_query qu, const char *fmt, va_list al); |
| 240 | |
| 241 | void adns__debug(adns_state ads, int serv, adns_query qu, |
| 242 | const char *fmt, ...) PRINTFFORMAT(4,5); |
| 243 | void adns__warn(adns_state ads, int serv, adns_query qu, |
| 244 | const char *fmt, ...) PRINTFFORMAT(4,5); |
| 245 | void adns__diag(adns_state ads, int serv, adns_query qu, |
| 246 | const char *fmt, ...) PRINTFFORMAT(4,5); |
| 247 | |
| 248 | int adns__vbuf_ensure(vbuf *vb, int want); |
| 249 | int adns__vbuf_appendstr(vbuf *vb, const char *data); /* does not include nul */ |
| 250 | int adns__vbuf_append(vbuf *vb, const byte *data, int len); |
| 251 | /* 1=>success, 0=>realloc failed */ |
| 252 | void adns__vbuf_appendq(vbuf *vb, const byte *data, int len); |
| 253 | void adns__vbuf_init(vbuf *vb); |
| 254 | void adns__vbuf_free(vbuf *vb); |
| 255 | |
| 256 | const char *adns__diag_domain(adns_state ads, int serv, adns_query qu, vbuf *vb, |
| 257 | int flags, const byte *dgram, int dglen, int cbyte); |
| 258 | /* Unpicks a domain in a datagram and returns a string suitable for |
| 259 | * printing it as. Never fails - if an error occurs, it will |
| 260 | * return some kind of string describing the error. |
| 261 | * |
| 262 | * serv may be -1 and qu may be 0. vb must have been initialised, |
| 263 | * and will be left in an arbitrary consistent state. |
| 264 | * |
| 265 | * Returns either vb->buf, or a pointer to a string literal. Do not modify |
| 266 | * vb before using the return value. |
| 267 | */ |
| 268 | |
| 269 | /* From transmit.c: */ |
| 270 | |
| 271 | adns_status adns__mkquery(adns_state ads, vbuf *vb, int *id_r, |
| 272 | const char *owner, int ol, |
| 273 | const typeinfo *typei, adns_queryflags flags); |
| 274 | /* Assembles a query packet in vb, and returns id at *id_r. */ |
| 275 | |
| 276 | void adns__query_tcp(adns_query qu, struct timeval now); |
| 277 | /* Query must be in state tcpwait/timew; it will be moved to a new state |
| 278 | * if possible and no further processing can be done on it for now. |
| 279 | * (Resulting state is one of tcpwait/timew (if server not connected), |
| 280 | * tcpsent/timew, child/childw or done/output.) |
| 281 | * |
| 282 | * adns__tcp_tryconnect should already have been called - _tcp |
| 283 | * will only use an existing connection (if there is one), which it |
| 284 | * may break. If the conn list lost then the caller is responsible for any |
| 285 | * reestablishment and retry. |
| 286 | */ |
| 287 | |
| 288 | void adns__query_udp(adns_query qu, struct timeval now); |
| 289 | /* Query must be in state udp/NONE; it will be moved to a new state, |
| 290 | * and no further processing can be done on it for now. |
| 291 | * (Resulting state is one of udp/timew, tcpwait/timew (if server not connected), |
| 292 | * tcpsent/timew, child/childw or done/output.) |
| 293 | */ |
| 294 | |
| 295 | /* From query.c: */ |
| 296 | |
| 297 | int adns__internal_submit(adns_state ads, adns_query *query_r, |
| 298 | const typeinfo *typei, vbuf *qumsg_vb, int id, |
| 299 | adns_queryflags flags, struct timeval now, |
| 300 | adns_status failstat, const qcontext *ctx); |
| 301 | /* Submits a query (for internal use, called during external submits). |
| 302 | * |
| 303 | * The new query is returned in *query_r, or we return adns_s_nomemory. |
| 304 | * |
| 305 | * The query datagram should already have been assembled in qumsg_vb; |
| 306 | * the memory for it is _taken over_ by this routine whether it |
| 307 | * succeeds or fails (if it succeeds, the vbuf is reused for qu->vb). |
| 308 | * |
| 309 | * If failstat is nonzero then if we are successful in creating the query |
| 310 | * it is immediately failed with code failstat (but _submit still succeds). |
| 311 | * |
| 312 | * ctx is copied byte-for-byte into the query. |
| 313 | */ |
| 314 | |
| 315 | void *adns__alloc_interim(adns_query qu, size_t sz); |
| 316 | /* Allocates some memory, and records which query it came from |
| 317 | * and how much there was. |
| 318 | * |
| 319 | * If an error occurs in the query, all its memory is simply freed. |
| 320 | * |
| 321 | * If the query succeeds, one large buffer will be made which is |
| 322 | * big enough for all these allocations, and then adns__alloc_final |
| 323 | * will get memory from this buffer. |
| 324 | * |
| 325 | * _alloc_interim can fail, in which case it will fail the query too, |
| 326 | * so nothing more need be done with it. |
| 327 | * |
| 328 | * adns__alloc_interim(qu,0) will not return 0, but it will not |
| 329 | * necessarily return a distinct pointer each time. |
| 330 | */ |
| 331 | |
| 332 | void *adns__alloc_mine(adns_query qu, size_t sz); |
| 333 | /* Like _interim, but does not record the length for later |
| 334 | * copying into the answer. This just ensures that the memory |
| 335 | * will be freed when we're done with the query. |
| 336 | */ |
| 337 | |
| 338 | void *adns__alloc_final(adns_query qu, size_t sz); |
| 339 | /* Cannot fail, and cannot return 0. |
| 340 | */ |
| 341 | |
| 342 | void adns__makefinal_block(adns_query qu, void **blpp, size_t sz); |
| 343 | void adns__makefinal_str(adns_query qu, char **strp); |
| 344 | |
| 345 | void adns__reset_cnameonly(adns_query qu); |
| 346 | /* Resets all of the memory management stuff etc. to |
| 347 | * take account of only the CNAME. Used when we find an error somewhere |
| 348 | * and want to just report the error (with perhaps CNAME info), and also |
| 349 | * when we're halfway through RRs in a datagram and discover that we |
| 350 | * need to retry the query. |
| 351 | */ |
| 352 | |
| 353 | void adns__query_done(adns_query qu); |
| 354 | void adns__query_fail(adns_query qu, adns_status stat); |
| 355 | |
| 356 | /* From reply.c: */ |
| 357 | |
| 358 | void adns__procdgram(adns_state ads, const byte *dgram, int len, |
| 359 | int serv, struct timeval now); |
| 360 | |
| 361 | /* From types.c: */ |
| 362 | |
| 363 | const typeinfo *adns__findtype(adns_rrtype type); |
| 364 | |
| 365 | /* From parse.c: */ |
| 366 | |
| 367 | typedef struct { |
| 368 | adns_state ads; |
| 369 | adns_query qu; |
| 370 | int serv; |
| 371 | const byte *dgram; |
| 372 | int dglen, max, cbyte, namelen; |
| 373 | int *dmend_r; |
| 374 | } findlabel_state; |
| 375 | |
| 376 | void adns__findlabel_start(findlabel_state *fls, adns_state ads, |
| 377 | int serv, adns_query qu, |
| 378 | const byte *dgram, int dglen, int max, |
| 379 | int dmbegin, int *dmend_rlater); |
| 380 | /* Finds labels in a domain in a datagram. |
| 381 | * |
| 382 | * Call this routine first. |
| 383 | * dmend_rlater may be null. ads (and of course fls) may not be. |
| 384 | * serv may be -1, qu may be null - they are for error reporting. |
| 385 | */ |
| 386 | |
| 387 | adns_status adns__findlabel_next(findlabel_state *fls, int *lablen_r, int *labstart_r); |
| 388 | /* Then, call this one repeatedly. |
| 389 | * |
| 390 | * It will return adns_s_ok if all is well, and tell you the length |
| 391 | * and start of successive labels. labstart_r may be null, but |
| 392 | * lablen_r must not be. |
| 393 | * |
| 394 | * After the last label, it will return with *lablen_r zero. |
| 395 | * Do not then call it again; instead, just throw away the findlabel_state. |
| 396 | * |
| 397 | * *dmend_rlater will have been set to point to the next part of |
| 398 | * the datagram after the label (or after the uncompressed part, |
| 399 | * if compression was used). *namelen_rlater will have been set |
| 400 | * to the length of the domain name (total length of labels plus |
| 401 | * 1 for each intervening dot). |
| 402 | * |
| 403 | * If the datagram appears to be truncated, *lablen_r will be -1. |
| 404 | * *dmend_rlater, *labstart_r and *namelen_r may contain garbage. |
| 405 | * Do not call _next again. |
| 406 | * |
| 407 | * There may also be errors, in which case *dmend_rlater, |
| 408 | * *namelen_rlater, *lablen_r and *labstart_r may contain garbage. |
| 409 | * Do not then call findlabel_next again. |
| 410 | */ |
| 411 | |
| 412 | adns_status adns__parse_domain(adns_state ads, int serv, adns_query qu, |
| 413 | vbuf *vb, int flags, |
| 414 | const byte *dgram, int dglen, int *cbyte_io, int max); |
| 415 | /* vb must already have been initialised; it will be reset if necessary. |
| 416 | * If there is truncation, vb->used will be set to 0; otherwise |
| 417 | * (if there is no error) vb will be null-terminated. |
| 418 | * If there is an error vb and *cbyte_io may be left indeterminate. |
| 419 | * |
| 420 | * serv may be -1 and qu may be 0 - they are used for error reporting only. |
| 421 | */ |
| 422 | |
| 423 | adns_status adns__findrr(adns_query qu, int serv, |
| 424 | const byte *dgram, int dglen, int *cbyte_io, |
| 425 | int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, |
| 426 | int *ownermatchedquery_r); |
| 427 | /* Finds the extent and some of the contents of an RR in a datagram |
| 428 | * and does some checks. The datagram is *dgram, length dglen, and |
| 429 | * the RR starts at *cbyte_io (which is updated afterwards to point |
| 430 | * to the end of the RR). |
| 431 | * |
| 432 | * The type, class and RRdata length and start are returned iff |
| 433 | * the corresponding pointer variables are not null. type_r and |
| 434 | * class_r may not be null. |
| 435 | * |
| 436 | * If ownermatchedquery_r != 0 then the owner domain of this |
| 437 | * RR will be compared with that in the query (or, if the query |
| 438 | * has gone to a CNAME lookup, with the canonical name). |
| 439 | * In this case, *ownermatchedquery_r will be set to 0 or 1. |
| 440 | * The query datagram (or CNAME datagram) MUST be valid and not truncated. |
| 441 | * |
| 442 | * If there is truncation then *type_r will be set to -1 and |
| 443 | * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be |
| 444 | * undefined. |
| 445 | * |
| 446 | * qu must obviously be non-null. |
| 447 | * |
| 448 | * If an error is returned then *type_r will be undefined too. |
| 449 | */ |
| 450 | |
| 451 | int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len); |
| 452 | |
| 453 | /* From event.c: */ |
| 454 | |
| 455 | void adns__tcp_broken(adns_state ads, const char *what, const char *why); |
| 456 | void adns__tcp_tryconnect(adns_state ads, struct timeval now); |
| 457 | |
| 458 | void adns__autosys(adns_state ads, struct timeval now); |
| 459 | /* Make all the system calls we want to if the application wants us to. */ |
| 460 | |
| 461 | /* Useful static inline functions: */ |
| 462 | |
| 463 | static inline void timevaladd(struct timeval *tv_io, long ms) { |
| 464 | struct timeval tmp; |
| 465 | assert(ms>=0); |
| 466 | tmp= *tv_io; |
| 467 | tmp.tv_usec += (ms%1000)*1000000; |
| 468 | tmp.tv_sec += ms/1000; |
| 469 | if (tmp.tv_usec >= 1000000) { tmp.tv_sec++; tmp.tv_usec -= 1000; } |
| 470 | *tv_io= tmp; |
| 471 | } |
| 472 | |
| 473 | static inline int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; } |
| 474 | static inline int ctype_digit(int c) { return c>='0' && c<='9'; } |
| 475 | static inline int ctype_alpha(int c) { |
| 476 | return (c >= 'a' && c <= 'z') || (c >= 'A' || c <= 'Z'); |
| 477 | } |
| 478 | |
| 479 | /* Useful macros */ |
| 480 | |
| 481 | #define MEM_ROUND(sz) \ |
| 482 | (( ((sz)+sizeof(union maxalign)-1) / sizeof(union maxalign) ) \ |
| 483 | * sizeof(union maxalign) ) |
| 484 | |
| 485 | #define LIST_INIT(list) ((list).head= (list).tail= 0) |
| 486 | |
| 487 | #define LIST_UNLINK_PART(list,node,part) \ |
| 488 | do { \ |
| 489 | if ((node)->back) (node)->back->part next= (node)->part next; \ |
| 490 | else (list).head= (node)->part next; \ |
| 491 | if ((node)->next) (node)->next->part back= (node)->part back; \ |
| 492 | else (list).tail= (node)->part back; \ |
| 493 | } while(0) |
| 494 | |
| 495 | #define LIST_LINK_TAIL_PART(list,node,part) \ |
| 496 | do { \ |
| 497 | (node)->part next= 0; \ |
| 498 | (node)->part back= (list).tail; \ |
| 499 | if ((list).tail) (list).tail->part next= (node); else (list).part head= (node); \ |
| 500 | (list).tail= (node); \ |
| 501 | } while(0) |
| 502 | |
| 503 | #define LIST_UNLINK(list,node) LIST_UNLINK_PART(list,node,) |
| 504 | #define LIST_LINK_TAIL(list,node) LIST_LINK_TAIL_PART(list,node,) |
| 505 | |
| 506 | #define GETIL_B(cb) (((dgram)[(cb)++]) & 0x0ff) |
| 507 | #define GET_B(cb,tv) ((tv)= GETIL_B((cb))) |
| 508 | #define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv)) |
| 509 | |
| 510 | #endif |