| 1 | /************************************************* |
| 2 | * fakens - A Fake Nameserver Program * |
| 3 | *************************************************/ |
| 4 | |
| 5 | /* This program exists to support the testing of DNS handling code in Exim. It |
| 6 | avoids the need to install special zones in a real nameserver. When Exim is |
| 7 | running in its (new) test harness, DNS lookups are first passed to this program |
| 8 | instead of to the real resolver. (With a few exceptions - see the discussion in |
| 9 | the test suite's README file.) The program is also passed the name of the Exim |
| 10 | spool directory; it expects to find its "zone files" in dnszones relative to |
| 11 | exim config_main_directory. Note that there is little checking in this program. The fake |
| 12 | zone files are assumed to be syntactically valid. |
| 13 | |
| 14 | The zones that are handled are found by scanning the dnszones directory. A file |
| 15 | whose name is of the form db.ip4.x is a zone file for .x.in-addr.arpa; a file |
| 16 | whose name is of the form db.ip6.x is a zone file for .x.ip6.arpa; a file of |
| 17 | the form db.anything.else is a zone file for .anything.else. A file of the form |
| 18 | qualify.x.y specifies the domain that is used to qualify single-component |
| 19 | names, except for the name "dontqualify". |
| 20 | |
| 21 | The arguments to the program are: |
| 22 | |
| 23 | the name of the Exim spool directory |
| 24 | the domain name that is being sought |
| 25 | the DNS record type that is being sought |
| 26 | |
| 27 | The output from the program is written to stdout. It is supposed to be in |
| 28 | exactly the same format as a traditional namserver response (see RFC 1035) so |
| 29 | that Exim can process it as normal. At present, no compression is used. |
| 30 | Error messages are written to stderr. |
| 31 | |
| 32 | The return codes from the program are zero for success, and otherwise the |
| 33 | values that are set in h_errno after a failing call to the normal resolver: |
| 34 | |
| 35 | 1 HOST_NOT_FOUND host not found (authoritative) |
| 36 | 2 TRY_AGAIN server failure |
| 37 | 3 NO_RECOVERY non-recoverable error |
| 38 | 4 NO_DATA valid name, no data of requested type |
| 39 | |
| 40 | In a real nameserver, TRY_AGAIN is also used for a non-authoritative not found, |
| 41 | but it is not used for that here. There is also one extra return code: |
| 42 | |
| 43 | 5 PASS_ON requests Exim to call res_search() |
| 44 | |
| 45 | This is used for zones that fakens does not recognize. It is also used if a |
| 46 | line in the zone file contains exactly this: |
| 47 | |
| 48 | PASS ON NOT FOUND |
| 49 | |
| 50 | and the domain is not found. It converts the the result to PASS_ON instead of |
| 51 | HOST_NOT_FOUND. |
| 52 | |
| 53 | Any DNS record line in a zone file can be prefixed with "DELAY=" and |
| 54 | a number of milliseconds (followed by whitespace). |
| 55 | |
| 56 | Any DNS record line in a zone file can be prefixed with "DNSSEC" and |
| 57 | at least one space; if all the records found by a lookup are marked |
| 58 | as such then the response will have the "AD" bit set. |
| 59 | |
| 60 | Any DNS record line in a zone file can be prefixed with "AA" and |
| 61 | at least one space; if all the records found by a lookup are marked |
| 62 | as such then the response will have the "AA" bit set. |
| 63 | |
| 64 | */ |
| 65 | |
| 66 | #include <ctype.h> |
| 67 | #include <stdarg.h> |
| 68 | #include <stdio.h> |
| 69 | #include <stdlib.h> |
| 70 | #include <string.h> |
| 71 | #include <netdb.h> |
| 72 | #include <errno.h> |
| 73 | #include <signal.h> |
| 74 | #include <arpa/nameser.h> |
| 75 | #include <sys/types.h> |
| 76 | #include <sys/time.h> |
| 77 | #include <dirent.h> |
| 78 | |
| 79 | #define FALSE 0 |
| 80 | #define TRUE 1 |
| 81 | #define PASS_ON 5 |
| 82 | |
| 83 | typedef int BOOL; |
| 84 | typedef unsigned char uschar; |
| 85 | |
| 86 | #define CS (char *) |
| 87 | #define CCS (const char *) |
| 88 | #define US (unsigned char *) |
| 89 | |
| 90 | #define Ustrcat(s,t) strcat(CS(s),CCS(t)) |
| 91 | #define Ustrchr(s,n) US strchr(CCS(s),n) |
| 92 | #define Ustrcmp(s,t) strcmp(CCS(s),CCS(t)) |
| 93 | #define Ustrcpy(s,t) strcpy(CS(s),CCS(t)) |
| 94 | #define Ustrlen(s) (int)strlen(CCS(s)) |
| 95 | #define Ustrncmp(s,t,n) strncmp(CCS(s),CCS(t),n) |
| 96 | #define Ustrncpy(s,t,n) strncpy(CS(s),CCS(t),n) |
| 97 | |
| 98 | typedef struct zoneitem { |
| 99 | uschar *zone; |
| 100 | uschar *zonefile; |
| 101 | } zoneitem; |
| 102 | |
| 103 | typedef struct tlist { |
| 104 | uschar *name; |
| 105 | int value; |
| 106 | } tlist; |
| 107 | |
| 108 | /* On some (older?) operating systems, the standard ns_t_xxx definitions are |
| 109 | not available, and only the older T_xxx ones exist in nameser.h. If ns_t_a is |
| 110 | not defined, assume we are in this state. A really old system might not even |
| 111 | know about AAAA and SRV at all. */ |
| 112 | |
| 113 | #ifndef ns_t_a |
| 114 | # define ns_t_a T_A |
| 115 | # define ns_t_ns T_NS |
| 116 | # define ns_t_cname T_CNAME |
| 117 | # define ns_t_soa T_SOA |
| 118 | # define ns_t_ptr T_PTR |
| 119 | # define ns_t_mx T_MX |
| 120 | # define ns_t_txt T_TXT |
| 121 | # define ns_t_aaaa T_AAAA |
| 122 | # define ns_t_srv T_SRV |
| 123 | # define ns_t_tlsa T_TLSA |
| 124 | # ifndef T_AAAA |
| 125 | # define T_AAAA 28 |
| 126 | # endif |
| 127 | # ifndef T_SRV |
| 128 | # define T_SRV 33 |
| 129 | # endif |
| 130 | # ifndef T_TLSA |
| 131 | # define T_TLSA 52 |
| 132 | # endif |
| 133 | #endif |
| 134 | |
| 135 | static tlist type_list[] = { |
| 136 | { US"A", ns_t_a }, |
| 137 | { US"NS", ns_t_ns }, |
| 138 | { US"CNAME", ns_t_cname }, |
| 139 | { US"SOA", ns_t_soa }, |
| 140 | { US"PTR", ns_t_ptr }, |
| 141 | { US"MX", ns_t_mx }, |
| 142 | { US"TXT", ns_t_txt }, |
| 143 | { US"AAAA", ns_t_aaaa }, |
| 144 | { US"SRV", ns_t_srv }, |
| 145 | { US"TLSA", ns_t_tlsa }, |
| 146 | { NULL, 0 } |
| 147 | }; |
| 148 | |
| 149 | |
| 150 | |
| 151 | /************************************************* |
| 152 | * Get memory and sprintf into it * |
| 153 | *************************************************/ |
| 154 | |
| 155 | /* This is used when building a table of zones and their files. |
| 156 | |
| 157 | Arguments: |
| 158 | format a format string |
| 159 | ... arguments |
| 160 | |
| 161 | Returns: pointer to formatted string |
| 162 | */ |
| 163 | |
| 164 | static uschar * |
| 165 | fcopystring(uschar *format, ...) |
| 166 | { |
| 167 | uschar *yield; |
| 168 | char buffer[256]; |
| 169 | va_list ap; |
| 170 | va_start(ap, format); |
| 171 | vsprintf(buffer, CS format, ap); |
| 172 | va_end(ap); |
| 173 | yield = (uschar *)malloc(Ustrlen(buffer) + 1); |
| 174 | Ustrcpy(yield, buffer); |
| 175 | return yield; |
| 176 | } |
| 177 | |
| 178 | |
| 179 | /************************************************* |
| 180 | * Pack name into memory * |
| 181 | *************************************************/ |
| 182 | |
| 183 | /* This function packs a domain name into memory according to DNS rules. At |
| 184 | present, it doesn't do any compression. |
| 185 | |
| 186 | Arguments: |
| 187 | name the name |
| 188 | pk where to put it |
| 189 | |
| 190 | Returns: the updated value of pk |
| 191 | */ |
| 192 | |
| 193 | static uschar * |
| 194 | packname(uschar *name, uschar *pk) |
| 195 | { |
| 196 | while (*name != 0) |
| 197 | { |
| 198 | uschar *p = name; |
| 199 | while (*p != 0 && *p != '.') p++; |
| 200 | *pk++ = (p - name); |
| 201 | memmove(pk, name, p - name); |
| 202 | pk += p - name; |
| 203 | name = (*p == 0)? p : p + 1; |
| 204 | } |
| 205 | *pk++ = 0; |
| 206 | return pk; |
| 207 | } |
| 208 | |
| 209 | uschar * |
| 210 | bytefield(uschar ** pp, uschar * pk) |
| 211 | { |
| 212 | unsigned value = 0; |
| 213 | uschar * p = *pp; |
| 214 | |
| 215 | while (isdigit(*p)) value = value*10 + *p++ - '0'; |
| 216 | while (isspace(*p)) p++; |
| 217 | *pp = p; |
| 218 | *pk++ = value & 255; |
| 219 | return pk; |
| 220 | } |
| 221 | |
| 222 | uschar * |
| 223 | shortfield(uschar ** pp, uschar * pk) |
| 224 | { |
| 225 | unsigned value = 0; |
| 226 | uschar * p = *pp; |
| 227 | |
| 228 | while (isdigit(*p)) value = value*10 + *p++ - '0'; |
| 229 | while (isspace(*p)) p++; |
| 230 | *pp = p; |
| 231 | *pk++ = (value >> 8) & 255; |
| 232 | *pk++ = value & 255; |
| 233 | return pk; |
| 234 | } |
| 235 | |
| 236 | uschar * |
| 237 | longfield(uschar ** pp, uschar * pk) |
| 238 | { |
| 239 | unsigned long value = 0; |
| 240 | uschar * p = *pp; |
| 241 | |
| 242 | while (isdigit(*p)) value = value*10 + *p++ - '0'; |
| 243 | while (isspace(*p)) p++; |
| 244 | *pp = p; |
| 245 | *pk++ = (value >> 24) & 255; |
| 246 | *pk++ = (value >> 16) & 255; |
| 247 | *pk++ = (value >> 8) & 255; |
| 248 | *pk++ = value & 255; |
| 249 | return pk; |
| 250 | } |
| 251 | |
| 252 | |
| 253 | |
| 254 | /*************************************************/ |
| 255 | |
| 256 | static void |
| 257 | milliwait(struct itimerval *itval) |
| 258 | { |
| 259 | sigset_t sigmask; |
| 260 | sigset_t old_sigmask; |
| 261 | |
| 262 | if (itval->it_value.tv_usec < 100 && itval->it_value.tv_sec == 0) |
| 263 | return; |
| 264 | (void)sigemptyset(&sigmask); /* Empty mask */ |
| 265 | (void)sigaddset(&sigmask, SIGALRM); /* Add SIGALRM */ |
| 266 | (void)sigprocmask(SIG_BLOCK, &sigmask, &old_sigmask); /* Block SIGALRM */ |
| 267 | (void)setitimer(ITIMER_REAL, itval, NULL); /* Start timer */ |
| 268 | (void)sigfillset(&sigmask); /* All signals */ |
| 269 | (void)sigdelset(&sigmask, SIGALRM); /* Remove SIGALRM */ |
| 270 | (void)sigsuspend(&sigmask); /* Until SIGALRM */ |
| 271 | (void)sigprocmask(SIG_SETMASK, &old_sigmask, NULL); /* Restore mask */ |
| 272 | } |
| 273 | |
| 274 | static void |
| 275 | millisleep(int msec) |
| 276 | { |
| 277 | struct itimerval itval; |
| 278 | itval.it_interval.tv_sec = 0; |
| 279 | itval.it_interval.tv_usec = 0; |
| 280 | itval.it_value.tv_sec = msec/1000; |
| 281 | itval.it_value.tv_usec = (msec % 1000) * 1000; |
| 282 | milliwait(&itval); |
| 283 | } |
| 284 | |
| 285 | |
| 286 | /************************************************* |
| 287 | * Scan file for RRs * |
| 288 | *************************************************/ |
| 289 | |
| 290 | /* This function scans an open "zone file" for appropriate records, and adds |
| 291 | any that are found to the output buffer. |
| 292 | |
| 293 | Arguments: |
| 294 | f the input FILE |
| 295 | zone the current zone name |
| 296 | domain the domain we are looking for |
| 297 | qtype the type of RR we want |
| 298 | qtypelen the length of qtype |
| 299 | pkptr points to the output buffer pointer; this is updated |
| 300 | countptr points to the record count; this is updated |
| 301 | dnssec points to the AD flag indicator; this updated |
| 302 | aa points to the AA flag indicator; this updated |
| 303 | |
| 304 | Returns: 0 on success, else HOST_NOT_FOUND or NO_DATA or NO_RECOVERY or |
| 305 | PASS_ON - the latter if a "PASS ON NOT FOUND" line is seen |
| 306 | */ |
| 307 | |
| 308 | static int |
| 309 | find_records(FILE *f, uschar *zone, uschar *domain, uschar *qtype, |
| 310 | int qtypelen, uschar **pkptr, int *countptr, BOOL * dnssec, BOOL * aa) |
| 311 | { |
| 312 | int yield = HOST_NOT_FOUND; |
| 313 | int domainlen = Ustrlen(domain); |
| 314 | BOOL pass_on_not_found = FALSE; |
| 315 | tlist *typeptr; |
| 316 | uschar *pk = *pkptr; |
| 317 | uschar buffer[256]; |
| 318 | uschar rrdomain[256]; |
| 319 | uschar RRdomain[256]; |
| 320 | |
| 321 | /* Decode the required type */ |
| 322 | |
| 323 | for (typeptr = type_list; typeptr->name != NULL; typeptr++) |
| 324 | { if (Ustrcmp(typeptr->name, qtype) == 0) break; } |
| 325 | if (typeptr->name == NULL) |
| 326 | { |
| 327 | fprintf(stderr, "fakens: unknown record type %s\n", qtype); |
| 328 | return NO_RECOVERY; |
| 329 | } |
| 330 | |
| 331 | rrdomain[0] = 0; /* No previous domain */ |
| 332 | (void)fseek(f, 0, SEEK_SET); /* Start again at the beginning */ |
| 333 | |
| 334 | *dnssec = TRUE; /* cancelled by first nonsecure rec found */ |
| 335 | *aa = TRUE; /* cancelled by first non-authoritive record */ |
| 336 | |
| 337 | /* Scan for RRs */ |
| 338 | |
| 339 | while (fgets(CS buffer, sizeof(buffer), f) != NULL) |
| 340 | { |
| 341 | uschar *rdlptr; |
| 342 | uschar *p, *ep, *pp; |
| 343 | BOOL found_cname = FALSE; |
| 344 | int i, value; |
| 345 | int tvalue = typeptr->value; |
| 346 | int qtlen = qtypelen; |
| 347 | BOOL rr_sec = FALSE; |
| 348 | BOOL rr_aa = FALSE; |
| 349 | int delay = 0; |
| 350 | |
| 351 | p = buffer; |
| 352 | while (isspace(*p)) p++; |
| 353 | if (*p == 0 || *p == ';') continue; |
| 354 | |
| 355 | if (Ustrncmp(p, US"PASS ON NOT FOUND", 17) == 0) |
| 356 | { |
| 357 | pass_on_not_found = TRUE; |
| 358 | continue; |
| 359 | } |
| 360 | |
| 361 | ep = buffer + Ustrlen(buffer); |
| 362 | while (isspace(ep[-1])) ep--; |
| 363 | *ep = 0; |
| 364 | |
| 365 | p = buffer; |
| 366 | for (;;) |
| 367 | { |
| 368 | if (Ustrncmp(p, US"DNSSEC ", 7) == 0) /* tagged as secure */ |
| 369 | { |
| 370 | rr_sec = TRUE; |
| 371 | p += 7; |
| 372 | } |
| 373 | else if (Ustrncmp(p, US"AA ", 3) == 0) /* tagged as authoritive */ |
| 374 | { |
| 375 | rr_aa = TRUE; |
| 376 | p += 3; |
| 377 | } |
| 378 | else if (Ustrncmp(p, US"DELAY=", 6) == 0) /* delay before response */ |
| 379 | { |
| 380 | for (p += 6; *p >= '0' && *p <= '9'; p++) delay = delay*10 + *p - '0'; |
| 381 | while (isspace(*p)) p++; |
| 382 | } |
| 383 | else |
| 384 | break; |
| 385 | } |
| 386 | |
| 387 | if (!isspace(*p)) |
| 388 | { |
| 389 | uschar *pp = rrdomain; |
| 390 | uschar *PP = RRdomain; |
| 391 | while (!isspace(*p)) |
| 392 | { |
| 393 | *pp++ = tolower(*p); |
| 394 | *PP++ = *p++; |
| 395 | } |
| 396 | if (pp[-1] != '.') |
| 397 | { |
| 398 | Ustrcpy(pp, zone); |
| 399 | Ustrcpy(PP, zone); |
| 400 | } |
| 401 | else |
| 402 | { |
| 403 | pp[-1] = 0; |
| 404 | PP[-1] = 0; |
| 405 | } |
| 406 | } |
| 407 | |
| 408 | /* Compare domain names; first check for a wildcard */ |
| 409 | |
| 410 | if (rrdomain[0] == '*') |
| 411 | { |
| 412 | int restlen = Ustrlen(rrdomain) - 1; |
| 413 | if (domainlen > restlen && |
| 414 | Ustrcmp(domain + domainlen - restlen, rrdomain + 1) != 0) continue; |
| 415 | } |
| 416 | |
| 417 | /* Not a wildcard RR */ |
| 418 | |
| 419 | else if (Ustrcmp(domain, rrdomain) != 0) continue; |
| 420 | |
| 421 | /* The domain matches */ |
| 422 | |
| 423 | if (yield == HOST_NOT_FOUND) yield = NO_DATA; |
| 424 | |
| 425 | /* Compare RR types; a CNAME record is always returned */ |
| 426 | |
| 427 | while (isspace(*p)) p++; |
| 428 | |
| 429 | if (Ustrncmp(p, "CNAME", 5) == 0) |
| 430 | { |
| 431 | tvalue = ns_t_cname; |
| 432 | qtlen = 5; |
| 433 | found_cname = TRUE; |
| 434 | } |
| 435 | else if (Ustrncmp(p, qtype, qtypelen) != 0 || !isspace(p[qtypelen])) continue; |
| 436 | |
| 437 | /* Found a relevant record */ |
| 438 | |
| 439 | if (delay) |
| 440 | millisleep(delay); |
| 441 | |
| 442 | if (!rr_sec) |
| 443 | *dnssec = FALSE; /* cancel AD return */ |
| 444 | |
| 445 | if (!rr_aa) |
| 446 | *aa = FALSE; /* cancel AA return */ |
| 447 | |
| 448 | yield = 0; |
| 449 | *countptr = *countptr + 1; |
| 450 | |
| 451 | p += qtlen; |
| 452 | while (isspace(*p)) p++; |
| 453 | |
| 454 | /* For a wildcard record, use the search name; otherwise use the record's |
| 455 | name in its original case because it might contain upper case letters. */ |
| 456 | |
| 457 | pk = packname((rrdomain[0] == '*')? domain : RRdomain, pk); |
| 458 | *pk++ = (tvalue >> 8) & 255; |
| 459 | *pk++ = (tvalue) & 255; |
| 460 | *pk++ = 0; |
| 461 | *pk++ = 1; /* class = IN */ |
| 462 | |
| 463 | pk += 4; /* TTL field; don't care */ |
| 464 | |
| 465 | rdlptr = pk; /* remember rdlength field */ |
| 466 | pk += 2; |
| 467 | |
| 468 | /* The rest of the data depends on the type */ |
| 469 | |
| 470 | switch (tvalue) |
| 471 | { |
| 472 | case ns_t_soa: |
| 473 | p = strtok(p, " "); |
| 474 | ep = p + strlen(p); |
| 475 | if (ep[-1] != '.') sprintf(CS ep, "%s.", zone); |
| 476 | pk = packname(p, pk); /* primary ns */ |
| 477 | p = strtok(NULL, " "); |
| 478 | pk = packname(p , pk); /* responsible mailbox */ |
| 479 | *(p += strlen(p)) = ' '; |
| 480 | while (isspace(*p)) p++; |
| 481 | pk = longfield(&p, pk); /* serial */ |
| 482 | pk = longfield(&p, pk); /* refresh */ |
| 483 | pk = longfield(&p, pk); /* retry */ |
| 484 | pk = longfield(&p, pk); /* expire */ |
| 485 | pk = longfield(&p, pk); /* minimum */ |
| 486 | break; |
| 487 | |
| 488 | case ns_t_a: |
| 489 | for (i = 0; i < 4; i++) |
| 490 | { |
| 491 | value = 0; |
| 492 | while (isdigit(*p)) value = value*10 + *p++ - '0'; |
| 493 | *pk++ = value; |
| 494 | p++; |
| 495 | } |
| 496 | break; |
| 497 | |
| 498 | /* The only occurrence of a double colon is for ::1 */ |
| 499 | case ns_t_aaaa: |
| 500 | if (Ustrcmp(p, "::1") == 0) |
| 501 | { |
| 502 | memset(pk, 0, 15); |
| 503 | pk += 15; |
| 504 | *pk++ = 1; |
| 505 | } |
| 506 | else for (i = 0; i < 8; i++) |
| 507 | { |
| 508 | value = 0; |
| 509 | while (isxdigit(*p)) |
| 510 | { |
| 511 | value = value * 16 + toupper(*p) - (isdigit(*p)? '0' : '7'); |
| 512 | p++; |
| 513 | } |
| 514 | *pk++ = (value >> 8) & 255; |
| 515 | *pk++ = value & 255; |
| 516 | p++; |
| 517 | } |
| 518 | break; |
| 519 | |
| 520 | case ns_t_mx: |
| 521 | pk = shortfield(&p, pk); |
| 522 | if (ep[-1] != '.') sprintf(CS ep, "%s.", zone); |
| 523 | pk = packname(p, pk); |
| 524 | break; |
| 525 | |
| 526 | case ns_t_txt: |
| 527 | pp = pk++; |
| 528 | if (*p == '"') p++; /* Should always be the case */ |
| 529 | while (*p != 0 && *p != '"') *pk++ = *p++; |
| 530 | *pp = pk - pp - 1; |
| 531 | break; |
| 532 | |
| 533 | case ns_t_tlsa: |
| 534 | pk = bytefield(&p, pk); /* usage */ |
| 535 | pk = bytefield(&p, pk); /* selector */ |
| 536 | pk = bytefield(&p, pk); /* match type */ |
| 537 | while (isxdigit(*p)) |
| 538 | { |
| 539 | value = toupper(*p) - (isdigit(*p) ? '0' : '7') << 4; |
| 540 | if (isxdigit(*++p)) |
| 541 | { |
| 542 | value |= toupper(*p) - (isdigit(*p) ? '0' : '7'); |
| 543 | p++; |
| 544 | } |
| 545 | *pk++ = value & 255; |
| 546 | } |
| 547 | |
| 548 | break; |
| 549 | |
| 550 | case ns_t_srv: |
| 551 | for (i = 0; i < 3; i++) |
| 552 | { |
| 553 | value = 0; |
| 554 | while (isdigit(*p)) value = value*10 + *p++ - '0'; |
| 555 | while (isspace(*p)) p++; |
| 556 | *pk++ = (value >> 8) & 255; |
| 557 | *pk++ = value & 255; |
| 558 | } |
| 559 | |
| 560 | /* Fall through */ |
| 561 | |
| 562 | case ns_t_cname: |
| 563 | case ns_t_ns: |
| 564 | case ns_t_ptr: |
| 565 | if (ep[-1] != '.') sprintf(CS ep, "%s.", zone); |
| 566 | pk = packname(p, pk); |
| 567 | break; |
| 568 | } |
| 569 | |
| 570 | /* Fill in the length, and we are done with this RR */ |
| 571 | |
| 572 | rdlptr[0] = ((pk - rdlptr - 2) >> 8) & 255; |
| 573 | rdlptr[1] = (pk -rdlptr - 2) & 255; |
| 574 | } |
| 575 | |
| 576 | *pkptr = pk; |
| 577 | return (yield == HOST_NOT_FOUND && pass_on_not_found)? PASS_ON : yield; |
| 578 | } |
| 579 | |
| 580 | |
| 581 | static void |
| 582 | alarmfn(int sig) |
| 583 | { |
| 584 | } |
| 585 | |
| 586 | /************************************************* |
| 587 | * Entry point and main program * |
| 588 | *************************************************/ |
| 589 | |
| 590 | int |
| 591 | main(int argc, char **argv) |
| 592 | { |
| 593 | FILE *f; |
| 594 | DIR *d; |
| 595 | int domlen, qtypelen; |
| 596 | int yield, count; |
| 597 | int i; |
| 598 | int zonecount = 0; |
| 599 | struct dirent *de; |
| 600 | zoneitem zones[32]; |
| 601 | uschar *qualify = NULL; |
| 602 | uschar *p, *zone; |
| 603 | uschar *zonefile = NULL; |
| 604 | uschar domain[256]; |
| 605 | uschar buffer[256]; |
| 606 | uschar qtype[12]; |
| 607 | uschar packet[2048 * 32 + 32]; |
| 608 | uschar *pk = packet; |
| 609 | BOOL dnssec; |
| 610 | BOOL aa; |
| 611 | |
| 612 | signal(SIGALRM, alarmfn); |
| 613 | |
| 614 | if (argc != 4) |
| 615 | { |
| 616 | fprintf(stderr, "fakens: expected 3 arguments, received %d\n", argc-1); |
| 617 | return NO_RECOVERY; |
| 618 | } |
| 619 | |
| 620 | /* Find the zones */ |
| 621 | |
| 622 | (void)sprintf(CS buffer, "%s/dnszones", argv[1]); |
| 623 | |
| 624 | d = opendir(CCS buffer); |
| 625 | if (d == NULL) |
| 626 | { |
| 627 | fprintf(stderr, "fakens: failed to opendir %s: %s\n", buffer, |
| 628 | strerror(errno)); |
| 629 | return NO_RECOVERY; |
| 630 | } |
| 631 | |
| 632 | while ((de = readdir(d)) != NULL) |
| 633 | { |
| 634 | uschar *name = US de->d_name; |
| 635 | if (Ustrncmp(name, "qualify.", 8) == 0) |
| 636 | { |
| 637 | qualify = fcopystring(US "%s", name + 7); |
| 638 | continue; |
| 639 | } |
| 640 | if (Ustrncmp(name, "db.", 3) != 0) continue; |
| 641 | if (Ustrncmp(name + 3, "ip4.", 4) == 0) |
| 642 | zones[zonecount].zone = fcopystring(US "%s.in-addr.arpa", name + 6); |
| 643 | else if (Ustrncmp(name + 3, "ip6.", 4) == 0) |
| 644 | zones[zonecount].zone = fcopystring(US "%s.ip6.arpa", name + 6); |
| 645 | else |
| 646 | zones[zonecount].zone = fcopystring(US "%s", name + 2); |
| 647 | zones[zonecount++].zonefile = fcopystring(US "%s", name); |
| 648 | } |
| 649 | (void)closedir(d); |
| 650 | |
| 651 | /* Get the RR type and upper case it, and check that we recognize it. */ |
| 652 | |
| 653 | Ustrncpy(qtype, argv[3], sizeof(qtype)); |
| 654 | qtypelen = Ustrlen(qtype); |
| 655 | for (p = qtype; *p != 0; p++) *p = toupper(*p); |
| 656 | |
| 657 | /* Find the domain, lower case it, deal with any specials, |
| 658 | check that it is in a zone that we handle, |
| 659 | and set up the zone file name. The zone names in the table all start with a |
| 660 | dot. */ |
| 661 | |
| 662 | domlen = Ustrlen(argv[2]); |
| 663 | if (argv[2][domlen-1] == '.') domlen--; |
| 664 | Ustrncpy(domain, argv[2], domlen); |
| 665 | domain[domlen] = 0; |
| 666 | for (i = 0; i < domlen; i++) domain[i] = tolower(domain[i]); |
| 667 | |
| 668 | if (Ustrcmp(domain, "manyhome.test.ex") == 0 && Ustrcmp(qtype, "A") == 0) |
| 669 | { |
| 670 | uschar *pk = packet + 12; |
| 671 | uschar *rdlptr; |
| 672 | int i, j; |
| 673 | |
| 674 | memset(packet, 0, 12); |
| 675 | |
| 676 | for (i = 104; i <= 111; i++) for (j = 0; j <= 255; j++) |
| 677 | { |
| 678 | pk = packname(domain, pk); |
| 679 | *pk++ = (ns_t_a >> 8) & 255; |
| 680 | *pk++ = (ns_t_a) & 255; |
| 681 | *pk++ = 0; |
| 682 | *pk++ = 1; /* class = IN */ |
| 683 | pk += 4; /* TTL field; don't care */ |
| 684 | rdlptr = pk; /* remember rdlength field */ |
| 685 | pk += 2; |
| 686 | |
| 687 | *pk++ = 10; *pk++ = 250; *pk++ = i; *pk++ = j; |
| 688 | |
| 689 | rdlptr[0] = ((pk - rdlptr - 2) >> 8) & 255; |
| 690 | rdlptr[1] = (pk - rdlptr - 2) & 255; |
| 691 | } |
| 692 | |
| 693 | packet[6] = (2048 >> 8) & 255; |
| 694 | packet[7] = 2048 & 255; |
| 695 | packet[10] = 0; |
| 696 | packet[11] = 0; |
| 697 | |
| 698 | (void)fwrite(packet, 1, pk - packet, stdout); |
| 699 | return 0; |
| 700 | } |
| 701 | |
| 702 | |
| 703 | if (Ustrchr(domain, '.') == NULL && qualify != NULL && |
| 704 | Ustrcmp(domain, "dontqualify") != 0) |
| 705 | { |
| 706 | Ustrcat(domain, qualify); |
| 707 | domlen += Ustrlen(qualify); |
| 708 | } |
| 709 | |
| 710 | for (i = 0; i < zonecount; i++) |
| 711 | { |
| 712 | int zlen; |
| 713 | zone = zones[i].zone; |
| 714 | zlen = Ustrlen(zone); |
| 715 | if (Ustrcmp(domain, zone+1) == 0 || (domlen >= zlen && |
| 716 | Ustrcmp(domain + domlen - zlen, zone) == 0)) |
| 717 | { |
| 718 | zonefile = zones[i].zonefile; |
| 719 | break; |
| 720 | } |
| 721 | } |
| 722 | |
| 723 | if (zonefile == NULL) |
| 724 | { |
| 725 | fprintf(stderr, "fakens: query not in faked zone: domain is: %s\n", domain); |
| 726 | return PASS_ON; |
| 727 | } |
| 728 | |
| 729 | (void)sprintf(CS buffer, "%s/dnszones/%s", argv[1], zonefile); |
| 730 | |
| 731 | /* Initialize the start of the response packet. We don't have to fake up |
| 732 | everything, because we know that Exim will look only at the answer and |
| 733 | additional section parts. */ |
| 734 | |
| 735 | memset(packet, 0, 12); |
| 736 | pk += 12; |
| 737 | |
| 738 | /* Open the zone file. */ |
| 739 | |
| 740 | f = fopen(CS buffer, "r"); |
| 741 | if (f == NULL) |
| 742 | { |
| 743 | fprintf(stderr, "fakens: failed to open %s: %s\n", buffer, strerror(errno)); |
| 744 | return NO_RECOVERY; |
| 745 | } |
| 746 | |
| 747 | /* Find the records we want, and add them to the result. */ |
| 748 | |
| 749 | count = 0; |
| 750 | yield = find_records(f, zone, domain, qtype, qtypelen, &pk, &count, &dnssec, &aa); |
| 751 | if (yield == NO_RECOVERY) goto END_OFF; |
| 752 | |
| 753 | packet[6] = (count >> 8) & 255; |
| 754 | packet[7] = count & 255; |
| 755 | |
| 756 | /* There is no need to return any additional records because Exim no longer |
| 757 | (from release 4.61) makes any use of them. */ |
| 758 | |
| 759 | packet[10] = 0; |
| 760 | packet[11] = 0; |
| 761 | |
| 762 | if (dnssec) |
| 763 | ((HEADER *)packet)->ad = 1; |
| 764 | |
| 765 | if (aa) |
| 766 | ((HEADER *)packet)->aa = 1; |
| 767 | |
| 768 | /* Close the zone file, write the result, and return. */ |
| 769 | |
| 770 | END_OFF: |
| 771 | (void)fclose(f); |
| 772 | (void)fwrite(packet, 1, pk - packet, stdout); |
| 773 | return yield; |
| 774 | } |
| 775 | |
| 776 | /* vi: aw ai sw=2 sts=2 ts=8 et |
| 777 | */ |
| 778 | /* End of fakens.c */ |