| 1 | /* $Cambridge: exim/src/src/host.c,v 1.9 2005/02/17 11:58:26 ph10 Exp $ */ |
| 2 | |
| 3 | /************************************************* |
| 4 | * Exim - an Internet mail transport agent * |
| 5 | *************************************************/ |
| 6 | |
| 7 | /* Copyright (c) University of Cambridge 1995 - 2005 */ |
| 8 | /* See the file NOTICE for conditions of use and distribution. */ |
| 9 | |
| 10 | /* Functions for finding hosts, either by gethostbyname(), gethostbyaddr(), or |
| 11 | directly via the DNS. When IPv6 is supported, getipnodebyname() and |
| 12 | getipnodebyaddr() may be used instead of gethostbyname() and gethostbyaddr(), |
| 13 | if the newer functions are available. This module also contains various other |
| 14 | functions concerned with hosts and addresses, and a random number function, |
| 15 | used for randomizing hosts with equal MXs but available for use in other parts |
| 16 | of Exim. */ |
| 17 | |
| 18 | |
| 19 | #include "exim.h" |
| 20 | |
| 21 | |
| 22 | /* Static variable for preserving the list of interface addresses in case it is |
| 23 | used more than once. */ |
| 24 | |
| 25 | static ip_address_item *local_interface_data = NULL; |
| 26 | |
| 27 | |
| 28 | #ifdef USE_INET_NTOA_FIX |
| 29 | /************************************************* |
| 30 | * Replacement for broken inet_ntoa() * |
| 31 | *************************************************/ |
| 32 | |
| 33 | /* On IRIX systems, gcc uses a different structure passing convention to the |
| 34 | native libraries. This causes inet_ntoa() to always yield 0.0.0.0 or |
| 35 | 255.255.255.255. To get round this, we provide a private version of the |
| 36 | function here. It is used only if USE_INET_NTOA_FIX is set, which should happen |
| 37 | only when gcc is in use on an IRIX system. Code send to me by J.T. Breitner, |
| 38 | with these comments: |
| 39 | |
| 40 | code by Stuart Levy |
| 41 | as seen in comp.sys.sgi.admin |
| 42 | |
| 43 | Arguments: sa an in_addr structure |
| 44 | Returns: pointer to static text string |
| 45 | */ |
| 46 | |
| 47 | char * |
| 48 | inet_ntoa(struct in_addr sa) |
| 49 | { |
| 50 | static uschar addr[20]; |
| 51 | sprintf(addr, "%d.%d.%d.%d", |
| 52 | (US &sa.s_addr)[0], |
| 53 | (US &sa.s_addr)[1], |
| 54 | (US &sa.s_addr)[2], |
| 55 | (US &sa.s_addr)[3]); |
| 56 | return addr; |
| 57 | } |
| 58 | #endif |
| 59 | |
| 60 | |
| 61 | |
| 62 | /************************************************* |
| 63 | * Random number generator * |
| 64 | *************************************************/ |
| 65 | |
| 66 | /* This is a simple pseudo-random number generator. It does not have to be |
| 67 | very good for the uses to which it is put. When running the regression tests, |
| 68 | start with a fixed seed. |
| 69 | |
| 70 | Arguments: |
| 71 | limit: one more than the largest number required |
| 72 | |
| 73 | Returns: a pseudo-random number in the range 0 to limit-1 |
| 74 | */ |
| 75 | |
| 76 | int |
| 77 | random_number(int limit) |
| 78 | { |
| 79 | if (random_seed == 0) |
| 80 | { |
| 81 | if (running_in_test_harness) random_seed = 42; else |
| 82 | { |
| 83 | int p = (int)getpid(); |
| 84 | random_seed = (int)time(NULL) ^ ((p << 16) | p); |
| 85 | } |
| 86 | } |
| 87 | random_seed = 1103515245 * random_seed + 12345; |
| 88 | return (unsigned int)(random_seed >> 16) % limit; |
| 89 | } |
| 90 | |
| 91 | |
| 92 | |
| 93 | /************************************************* |
| 94 | * Sort addresses when testing * |
| 95 | *************************************************/ |
| 96 | |
| 97 | /* This function is called only when running in the test harness. It sorts a |
| 98 | number of multihomed host IP addresses into the order, so as to get |
| 99 | repeatability. This doesn't have to be efficient. But don't interchange IPv4 |
| 100 | and IPv6 addresses! |
| 101 | |
| 102 | Arguments: |
| 103 | host -> the first host item |
| 104 | last -> the last host item |
| 105 | |
| 106 | Returns: nothing |
| 107 | */ |
| 108 | |
| 109 | static void |
| 110 | sort_addresses(host_item *host, host_item *last) |
| 111 | { |
| 112 | BOOL done = FALSE; |
| 113 | while (!done) |
| 114 | { |
| 115 | host_item *h; |
| 116 | done = TRUE; |
| 117 | for (h = host; h != last; h = h->next) |
| 118 | { |
| 119 | if ((Ustrchr(h->address, ':') == NULL) != |
| 120 | (Ustrchr(h->next->address, ':') == NULL)) |
| 121 | continue; |
| 122 | if (Ustrcmp(h->address, h->next->address) > 0) |
| 123 | { |
| 124 | uschar *temp = h->address; |
| 125 | h->address = h->next->address; |
| 126 | h->next->address = temp; |
| 127 | done = FALSE; |
| 128 | } |
| 129 | } |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | |
| 134 | |
| 135 | /************************************************* |
| 136 | * Build chain of host items from list * |
| 137 | *************************************************/ |
| 138 | |
| 139 | /* This function builds a chain of host items from a textual list of host |
| 140 | names. It does not do any lookups. If randomize is true, the chain is build in |
| 141 | a randomized order. There may be multiple groups of independently randomized |
| 142 | hosts; they are delimited by a host name consisting of just "+". |
| 143 | |
| 144 | Arguments: |
| 145 | anchor anchor for the chain |
| 146 | list text list |
| 147 | randomize TRUE for randomizing |
| 148 | |
| 149 | Returns: nothing |
| 150 | */ |
| 151 | |
| 152 | void |
| 153 | host_build_hostlist(host_item **anchor, uschar *list, BOOL randomize) |
| 154 | { |
| 155 | int sep = 0; |
| 156 | int fake_mx = MX_NONE; /* This value is actually -1 */ |
| 157 | uschar *name; |
| 158 | uschar buffer[1024]; |
| 159 | |
| 160 | if (list == NULL) return; |
| 161 | if (randomize) fake_mx--; /* Start at -2 for randomizing */ |
| 162 | |
| 163 | *anchor = NULL; |
| 164 | |
| 165 | while ((name = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL) |
| 166 | { |
| 167 | host_item *h; |
| 168 | |
| 169 | if (name[0] == '+' && name[1] == 0) /* "+" delimits a randomized group */ |
| 170 | { /* ignore if not randomizing */ |
| 171 | if (randomize) fake_mx--; |
| 172 | continue; |
| 173 | } |
| 174 | |
| 175 | h = store_get(sizeof(host_item)); |
| 176 | h->name = string_copy(name); |
| 177 | h->address = NULL; |
| 178 | h->port = PORT_NONE; |
| 179 | h->mx = fake_mx; |
| 180 | h->sort_key = randomize? (-fake_mx)*1000 + random_number(1000) : 0; |
| 181 | h->status = hstatus_unknown; |
| 182 | h->why = hwhy_unknown; |
| 183 | h->last_try = 0; |
| 184 | |
| 185 | if (*anchor == NULL) |
| 186 | { |
| 187 | h->next = NULL; |
| 188 | *anchor = h; |
| 189 | } |
| 190 | else |
| 191 | { |
| 192 | host_item *hh = *anchor; |
| 193 | if (h->sort_key < hh->sort_key) |
| 194 | { |
| 195 | h->next = hh; |
| 196 | *anchor = h; |
| 197 | } |
| 198 | else |
| 199 | { |
| 200 | while (hh->next != NULL && h->sort_key >= (hh->next)->sort_key) |
| 201 | hh = hh->next; |
| 202 | h->next = hh->next; |
| 203 | hh->next = h; |
| 204 | } |
| 205 | } |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | |
| 210 | |
| 211 | |
| 212 | |
| 213 | /************************************************* |
| 214 | * Extract port from address string * |
| 215 | *************************************************/ |
| 216 | |
| 217 | /* In the spool file, and in the -oMa and -oMi options, a host plus port is |
| 218 | given as an IP address followed by a dot and a port number. This function |
| 219 | decodes this. |
| 220 | |
| 221 | An alternative format for the -oMa and -oMi options is [ip address]:port which |
| 222 | is what Exim 4 uses for output, because it seems to becoming commonly used, |
| 223 | whereas the dot form confuses some programs/people. So we recognize that form |
| 224 | too. |
| 225 | |
| 226 | Argument: |
| 227 | address points to the string; if there is a port, the '.' in the string |
| 228 | is overwritten with zero to terminate the address; if the string |
| 229 | is in the [xxx]:ppp format, the address is shifted left and the |
| 230 | brackets are removed |
| 231 | |
| 232 | Returns: 0 if there is no port, else the port number. If there's a syntax |
| 233 | error, leave the incoming address alone, and return 0. |
| 234 | */ |
| 235 | |
| 236 | int |
| 237 | host_extract_port(uschar *address) |
| 238 | { |
| 239 | int port = 0; |
| 240 | uschar *endptr; |
| 241 | |
| 242 | /* Handle the "bracketed with colon on the end" format */ |
| 243 | |
| 244 | if (*address == '[') |
| 245 | { |
| 246 | uschar *rb = address + 1; |
| 247 | while (*rb != 0 && *rb != ']') rb++; |
| 248 | if (*rb++ == 0) return 0; /* Missing ]; leave invalid address */ |
| 249 | if (*rb == ':') |
| 250 | { |
| 251 | port = Ustrtol(rb + 1, &endptr, 10); |
| 252 | if (*endptr != 0) return 0; /* Invalid port; leave invalid address */ |
| 253 | } |
| 254 | else if (*rb != 0) return 0; /* Bad syntax; leave invalid address */ |
| 255 | memmove(address, address + 1, rb - address - 2); |
| 256 | rb[-2] = 0; |
| 257 | } |
| 258 | |
| 259 | /* Handle the "dot on the end" format */ |
| 260 | |
| 261 | else |
| 262 | { |
| 263 | int skip = -3; /* Skip 3 dots in IPv4 addresses */ |
| 264 | address--; |
| 265 | while (*(++address) != 0) |
| 266 | { |
| 267 | int ch = *address; |
| 268 | if (ch == ':') skip = 0; /* Skip 0 dots in IPv6 addresses */ |
| 269 | else if (ch == '.' && skip++ >= 0) break; |
| 270 | } |
| 271 | if (*address == 0) return 0; |
| 272 | port = Ustrtol(address + 1, &endptr, 10); |
| 273 | if (*endptr != 0) return 0; /* Invalid port; leave invalid address */ |
| 274 | *address = 0; |
| 275 | } |
| 276 | |
| 277 | return port; |
| 278 | } |
| 279 | |
| 280 | |
| 281 | |
| 282 | #ifndef STAND_ALONE /* Omit when standalone testing */ |
| 283 | |
| 284 | /************************************************* |
| 285 | * Build sender_fullhost and sender_rcvhost * |
| 286 | *************************************************/ |
| 287 | |
| 288 | /* This function is called when sender_host_name and/or sender_helo_name |
| 289 | have been set. Or might have been set - for a local message read off the spool |
| 290 | they won't be. In that case, do nothing. Otherwise, set up the fullhost string |
| 291 | as follows: |
| 292 | |
| 293 | (a) No sender_host_name or sender_helo_name: "[ip address]" |
| 294 | (b) Just sender_host_name: "host_name [ip address]" |
| 295 | (c) Just sender_helo_name: "(helo_name) [ip address]" |
| 296 | (d) The two are identical: "host_name [ip address]" |
| 297 | (e) The two are different: "host_name (helo_name) [ip address]" |
| 298 | |
| 299 | If log_incoming_port is set, the sending host's port number is added to the IP |
| 300 | address. |
| 301 | |
| 302 | This function also builds sender_rcvhost for use in Received: lines, whose |
| 303 | syntax is a bit different. This value also includes the RFC 1413 identity. |
| 304 | There wouldn't be two different variables if I had got all this right in the |
| 305 | first place. |
| 306 | |
| 307 | Because this data may survive over more than one incoming SMTP message, it has |
| 308 | to be in permanent store. |
| 309 | |
| 310 | Arguments: none |
| 311 | Returns: nothing |
| 312 | */ |
| 313 | |
| 314 | void |
| 315 | host_build_sender_fullhost(void) |
| 316 | { |
| 317 | uschar *address; |
| 318 | int old_pool = store_pool; |
| 319 | |
| 320 | if (sender_host_address == NULL) return; |
| 321 | |
| 322 | store_pool = POOL_PERM; |
| 323 | |
| 324 | /* Set up address, with or without the port. After discussion, it seems that |
| 325 | the only format that doesn't cause trouble is [aaaa]:pppp. However, we can't |
| 326 | use this directly as the first item for Received: because it ain't an RFC 2822 |
| 327 | domain. Sigh. */ |
| 328 | |
| 329 | address = string_sprintf("[%s]:%d", sender_host_address, sender_host_port); |
| 330 | if ((log_extra_selector & LX_incoming_port) == 0 || sender_host_port <= 0) |
| 331 | *(Ustrrchr(address, ':')) = 0; |
| 332 | |
| 333 | /* Host name is not verified */ |
| 334 | |
| 335 | if (sender_host_name == NULL) |
| 336 | { |
| 337 | uschar *portptr = Ustrstr(address, "]:"); |
| 338 | int size = 0; |
| 339 | int ptr = 0; |
| 340 | int adlen; /* Sun compiler doesn't like ++ in initializers */ |
| 341 | |
| 342 | adlen = (portptr == NULL)? Ustrlen(address) : (++portptr - address); |
| 343 | sender_fullhost = (sender_helo_name == NULL)? address : |
| 344 | string_sprintf("(%s) %s", sender_helo_name, address); |
| 345 | |
| 346 | sender_rcvhost = string_cat(NULL, &size, &ptr, address, adlen); |
| 347 | |
| 348 | if (sender_ident != NULL || sender_helo_name != NULL || portptr != NULL) |
| 349 | { |
| 350 | int firstptr; |
| 351 | sender_rcvhost = string_cat(sender_rcvhost, &size, &ptr, US" (", 2); |
| 352 | firstptr = ptr; |
| 353 | |
| 354 | if (portptr != NULL) |
| 355 | sender_rcvhost = string_append(sender_rcvhost, &size, &ptr, 2, US"port=", |
| 356 | portptr + 1); |
| 357 | |
| 358 | if (sender_helo_name != NULL) |
| 359 | sender_rcvhost = string_append(sender_rcvhost, &size, &ptr, 2, |
| 360 | (firstptr == ptr)? US"helo=" : US" helo=", sender_helo_name); |
| 361 | |
| 362 | if (sender_ident != NULL) |
| 363 | sender_rcvhost = string_append(sender_rcvhost, &size, &ptr, 2, |
| 364 | (firstptr == ptr)? US"ident=" : US" ident=", sender_ident); |
| 365 | |
| 366 | sender_rcvhost = string_cat(sender_rcvhost, &size, &ptr, US")", 1); |
| 367 | } |
| 368 | |
| 369 | sender_rcvhost[ptr] = 0; /* string_cat() always leaves room */ |
| 370 | |
| 371 | /* Release store, because string_cat allocated a minimum of 100 bytes that |
| 372 | are rarely completely used. */ |
| 373 | |
| 374 | store_reset(sender_rcvhost + ptr + 1); |
| 375 | } |
| 376 | |
| 377 | /* Host name is known and verified. */ |
| 378 | |
| 379 | else |
| 380 | { |
| 381 | int len; |
| 382 | if (sender_helo_name == NULL || |
| 383 | strcmpic(sender_host_name, sender_helo_name) == 0 || |
| 384 | (sender_helo_name[0] == '[' && |
| 385 | sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']' && |
| 386 | strncmpic(sender_helo_name+1, sender_host_address, len - 2) == 0)) |
| 387 | { |
| 388 | sender_fullhost = string_sprintf("%s %s", sender_host_name, address); |
| 389 | sender_rcvhost = (sender_ident == NULL)? |
| 390 | string_sprintf("%s (%s)", sender_host_name, address) : |
| 391 | string_sprintf("%s (%s ident=%s)", sender_host_name, address, |
| 392 | sender_ident); |
| 393 | } |
| 394 | else |
| 395 | { |
| 396 | sender_fullhost = string_sprintf("%s (%s) %s", sender_host_name, |
| 397 | sender_helo_name, address); |
| 398 | sender_rcvhost = (sender_ident == NULL)? |
| 399 | string_sprintf("%s (%s helo=%s)", sender_host_name, |
| 400 | address, sender_helo_name) : |
| 401 | string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name, |
| 402 | address, sender_helo_name, sender_ident); |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | store_pool = old_pool; |
| 407 | |
| 408 | DEBUG(D_host_lookup) debug_printf("sender_fullhost = %s\n", sender_fullhost); |
| 409 | DEBUG(D_host_lookup) debug_printf("sender_rcvhost = %s\n", sender_rcvhost); |
| 410 | } |
| 411 | |
| 412 | |
| 413 | |
| 414 | /************************************************* |
| 415 | * Build host+ident message * |
| 416 | *************************************************/ |
| 417 | |
| 418 | /* Used when logging rejections and various ACL and SMTP incidents. The text |
| 419 | return depends on whether sender_fullhost and sender_ident are set or not: |
| 420 | |
| 421 | no ident, no host => U=unknown |
| 422 | no ident, host set => H=sender_fullhost |
| 423 | ident set, no host => U=ident |
| 424 | ident set, host set => H=sender_fullhost U=ident |
| 425 | |
| 426 | Arguments: |
| 427 | useflag TRUE if first item to be flagged (H= or U=); if there are two |
| 428 | items, the second is always flagged |
| 429 | |
| 430 | Returns: pointer to a string in big_buffer |
| 431 | */ |
| 432 | |
| 433 | uschar * |
| 434 | host_and_ident(BOOL useflag) |
| 435 | { |
| 436 | if (sender_fullhost == NULL) |
| 437 | { |
| 438 | (void)string_format(big_buffer, big_buffer_size, "%s%s", useflag? "U=" : "", |
| 439 | (sender_ident == NULL)? US"unknown" : sender_ident); |
| 440 | } |
| 441 | else |
| 442 | { |
| 443 | uschar *flag = useflag? US"H=" : US""; |
| 444 | uschar *iface = US""; |
| 445 | if ((log_extra_selector & LX_incoming_interface) != 0 && |
| 446 | interface_address != NULL) |
| 447 | iface = string_sprintf(" I=[%s]:%d", interface_address, interface_port); |
| 448 | if (sender_ident == NULL) |
| 449 | (void)string_format(big_buffer, big_buffer_size, "%s%s%s", |
| 450 | flag, sender_fullhost, iface); |
| 451 | else |
| 452 | (void)string_format(big_buffer, big_buffer_size, "%s%s%s U=%s", |
| 453 | flag, sender_fullhost, iface, sender_ident); |
| 454 | } |
| 455 | return big_buffer; |
| 456 | } |
| 457 | |
| 458 | #endif /* STAND_ALONE */ |
| 459 | |
| 460 | |
| 461 | |
| 462 | |
| 463 | /************************************************* |
| 464 | * Build list of local interfaces * |
| 465 | *************************************************/ |
| 466 | |
| 467 | /* This function interprets the contents of the local_interfaces or |
| 468 | extra_local_interfaces options, and creates an ip_address_item block for each |
| 469 | item on the list. There is no special interpretation of any IP addresses; in |
| 470 | particular, 0.0.0.0 and ::0 are returned without modification. If any address |
| 471 | includes a port, it is set in the block. Otherwise the port value is set to |
| 472 | zero. |
| 473 | |
| 474 | Arguments: |
| 475 | list the list |
| 476 | name the name of the option being expanded |
| 477 | |
| 478 | Returns: a chain of ip_address_items, each containing to a textual |
| 479 | version of an IP address, and a port number (host order) or |
| 480 | zero if no port was given with the address |
| 481 | */ |
| 482 | |
| 483 | ip_address_item * |
| 484 | host_build_ifacelist(uschar *list, uschar *name) |
| 485 | { |
| 486 | int sep = 0; |
| 487 | uschar *s; |
| 488 | uschar buffer[64]; |
| 489 | ip_address_item *yield = NULL; |
| 490 | ip_address_item *last = NULL; |
| 491 | ip_address_item *next; |
| 492 | |
| 493 | while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL) |
| 494 | { |
| 495 | int port = host_extract_port(s); /* Leaves just the IP address */ |
| 496 | if (string_is_ip_address(s, NULL) == 0) |
| 497 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s", |
| 498 | s, name); |
| 499 | |
| 500 | /* This use of strcpy() is OK because we have checked that s is a valid IP |
| 501 | address above. The field in the ip_address_item is large enough to hold an |
| 502 | IPv6 address. */ |
| 503 | |
| 504 | next = store_get(sizeof(ip_address_item)); |
| 505 | next->next = NULL; |
| 506 | Ustrcpy(next->address, s); |
| 507 | next->port = port; |
| 508 | next->v6_include_v4 = FALSE; |
| 509 | |
| 510 | if (yield == NULL) yield = last = next; else |
| 511 | { |
| 512 | last->next = next; |
| 513 | last = next; |
| 514 | } |
| 515 | } |
| 516 | |
| 517 | return yield; |
| 518 | } |
| 519 | |
| 520 | |
| 521 | |
| 522 | |
| 523 | |
| 524 | /************************************************* |
| 525 | * Find addresses on local interfaces * |
| 526 | *************************************************/ |
| 527 | |
| 528 | /* This function finds the addresses of local IP interfaces. These are used |
| 529 | when testing for routing to the local host. As the function may be called more |
| 530 | than once, the list is preserved in permanent store, pointed to by a static |
| 531 | variable, to save doing the work more than once per process. |
| 532 | |
| 533 | The generic list of interfaces is obtained by calling host_build_ifacelist() |
| 534 | for local_interfaces and extra_local_interfaces. This list scanned to remove |
| 535 | duplicates (which may exist with different ports - not relevant here). If |
| 536 | either of the wildcard IP addresses (0.0.0.0 and ::0) are encountered, they are |
| 537 | replaced by the appropriate (IPv4 or IPv6) list of actual local interfaces, |
| 538 | obtained from os_find_running_interfaces(). |
| 539 | |
| 540 | Arguments: none |
| 541 | Returns: a chain of ip_address_items, each containing to a textual |
| 542 | version of an IP address; the port numbers are not relevant |
| 543 | */ |
| 544 | |
| 545 | |
| 546 | /* First, a local subfunction to add an interface to a list in permanent store, |
| 547 | but only if there isn't a previous copy of that address on the list. */ |
| 548 | |
| 549 | static ip_address_item * |
| 550 | add_unique_interface(ip_address_item *list, ip_address_item *ipa) |
| 551 | { |
| 552 | ip_address_item *ipa2; |
| 553 | for (ipa2 = list; ipa2 != NULL; ipa2 = ipa2->next) |
| 554 | if (Ustrcmp(ipa2->address, ipa->address) == 0) return list; |
| 555 | ipa2 = store_get_perm(sizeof(ip_address_item)); |
| 556 | *ipa2 = *ipa; |
| 557 | ipa2->next = list; |
| 558 | return ipa2; |
| 559 | } |
| 560 | |
| 561 | |
| 562 | /* This is the globally visible function */ |
| 563 | |
| 564 | ip_address_item * |
| 565 | host_find_interfaces(void) |
| 566 | { |
| 567 | ip_address_item *running_interfaces = NULL; |
| 568 | |
| 569 | if (local_interface_data == NULL) |
| 570 | { |
| 571 | void *reset_item = store_get(0); |
| 572 | ip_address_item *dlist = host_build_ifacelist(local_interfaces, |
| 573 | US"local_interfaces"); |
| 574 | ip_address_item *xlist = host_build_ifacelist(extra_local_interfaces, |
| 575 | US"extra_local_interfaces"); |
| 576 | ip_address_item *ipa; |
| 577 | |
| 578 | if (dlist == NULL) dlist = xlist; else |
| 579 | { |
| 580 | for (ipa = dlist; ipa->next != NULL; ipa = ipa->next); |
| 581 | ipa->next = xlist; |
| 582 | } |
| 583 | |
| 584 | for (ipa = dlist; ipa != NULL; ipa = ipa->next) |
| 585 | { |
| 586 | if (Ustrcmp(ipa->address, "0.0.0.0") == 0 || |
| 587 | Ustrcmp(ipa->address, "::0") == 0) |
| 588 | { |
| 589 | ip_address_item *ipa2; |
| 590 | BOOL ipv6 = ipa->address[0] == ':'; |
| 591 | if (running_interfaces == NULL) |
| 592 | running_interfaces = os_find_running_interfaces(); |
| 593 | for (ipa2 = running_interfaces; ipa2 != NULL; ipa2 = ipa2->next) |
| 594 | { |
| 595 | if ((Ustrchr(ipa2->address, ':') != NULL) == ipv6) |
| 596 | local_interface_data = add_unique_interface(local_interface_data, |
| 597 | ipa2); |
| 598 | } |
| 599 | } |
| 600 | else |
| 601 | { |
| 602 | local_interface_data = add_unique_interface(local_interface_data, ipa); |
| 603 | DEBUG(D_interface) |
| 604 | { |
| 605 | debug_printf("Configured local interface: address=%s", ipa->address); |
| 606 | if (ipa->port != 0) debug_printf(" port=%d", ipa->port); |
| 607 | debug_printf("\n"); |
| 608 | } |
| 609 | } |
| 610 | } |
| 611 | store_reset(reset_item); |
| 612 | } |
| 613 | |
| 614 | return local_interface_data; |
| 615 | } |
| 616 | |
| 617 | |
| 618 | |
| 619 | |
| 620 | |
| 621 | /************************************************* |
| 622 | * Convert network IP address to text * |
| 623 | *************************************************/ |
| 624 | |
| 625 | /* Given an IPv4 or IPv6 address in binary, convert it to a text |
| 626 | string and return the result in a piece of new store. The address can |
| 627 | either be given directly, or passed over in a sockaddr structure. Note |
| 628 | that this isn't the converse of host_aton() because of byte ordering |
| 629 | differences. See host_nmtoa() below. |
| 630 | |
| 631 | Arguments: |
| 632 | type if < 0 then arg points to a sockaddr, else |
| 633 | either AF_INET or AF_INET6 |
| 634 | arg points to a sockaddr if type is < 0, or |
| 635 | points to an IPv4 address (32 bits), or |
| 636 | points to an IPv6 address (128 bits), |
| 637 | in both cases, in network byte order |
| 638 | buffer if NULL, the result is returned in gotten store; |
| 639 | else points to a buffer to hold the answer |
| 640 | portptr points to where to put the port number, if non NULL; only |
| 641 | used when type < 0 |
| 642 | |
| 643 | Returns: pointer to character string |
| 644 | */ |
| 645 | |
| 646 | uschar * |
| 647 | host_ntoa(int type, const void *arg, uschar *buffer, int *portptr) |
| 648 | { |
| 649 | uschar *yield; |
| 650 | |
| 651 | /* The new world. It is annoying that we have to fish out the address from |
| 652 | different places in the block, depending on what kind of address it is. It |
| 653 | is also a pain that inet_ntop() returns a const uschar *, whereas the IPv4 |
| 654 | function inet_ntoa() returns just uschar *, and some picky compilers insist |
| 655 | on warning if one assigns a const uschar * to a uschar *. Hence the casts. */ |
| 656 | |
| 657 | #if HAVE_IPV6 |
| 658 | uschar addr_buffer[46]; |
| 659 | if (type < 0) |
| 660 | { |
| 661 | int family = ((struct sockaddr *)arg)->sa_family; |
| 662 | if (family == AF_INET6) |
| 663 | { |
| 664 | struct sockaddr_in6 *sk = (struct sockaddr_in6 *)arg; |
| 665 | yield = (uschar *)inet_ntop(family, &(sk->sin6_addr), CS addr_buffer, |
| 666 | sizeof(addr_buffer)); |
| 667 | if (portptr != NULL) *portptr = ntohs(sk->sin6_port); |
| 668 | } |
| 669 | else |
| 670 | { |
| 671 | struct sockaddr_in *sk = (struct sockaddr_in *)arg; |
| 672 | yield = (uschar *)inet_ntop(family, &(sk->sin_addr), CS addr_buffer, |
| 673 | sizeof(addr_buffer)); |
| 674 | if (portptr != NULL) *portptr = ntohs(sk->sin_port); |
| 675 | } |
| 676 | } |
| 677 | else |
| 678 | { |
| 679 | yield = (uschar *)inet_ntop(type, arg, CS addr_buffer, sizeof(addr_buffer)); |
| 680 | } |
| 681 | |
| 682 | /* If the result is a mapped IPv4 address, show it in V4 format. */ |
| 683 | |
| 684 | if (Ustrncmp(yield, "::ffff:", 7) == 0) yield += 7; |
| 685 | |
| 686 | #else /* HAVE_IPV6 */ |
| 687 | |
| 688 | /* The old world */ |
| 689 | |
| 690 | if (type < 0) |
| 691 | { |
| 692 | yield = US inet_ntoa(((struct sockaddr_in *)arg)->sin_addr); |
| 693 | if (portptr != NULL) *portptr = ntohs(((struct sockaddr_in *)arg)->sin_port); |
| 694 | } |
| 695 | else |
| 696 | yield = US inet_ntoa(*((struct in_addr *)arg)); |
| 697 | #endif |
| 698 | |
| 699 | /* If there is no buffer, put the string into some new store. */ |
| 700 | |
| 701 | if (buffer == NULL) return string_copy(yield); |
| 702 | |
| 703 | /* Callers of this function with a non-NULL buffer must ensure that it is |
| 704 | large enough to hold an IPv6 address, namely, at least 46 bytes. That's what |
| 705 | makes this use of strcpy() OK. */ |
| 706 | |
| 707 | Ustrcpy(buffer, yield); |
| 708 | return buffer; |
| 709 | } |
| 710 | |
| 711 | |
| 712 | |
| 713 | |
| 714 | /************************************************* |
| 715 | * Convert address text to binary * |
| 716 | *************************************************/ |
| 717 | |
| 718 | /* Given the textual form of an IP address, convert it to binary in an |
| 719 | array of ints. IPv4 addresses occupy one int; IPv6 addresses occupy 4 ints. |
| 720 | The result has the first byte in the most significant byte of the first int. In |
| 721 | other words, the result is not in network byte order, but in host byte order. |
| 722 | As a result, this is not the converse of host_ntoa(), which expects network |
| 723 | byte order. See host_nmtoa() below. |
| 724 | |
| 725 | Arguments: |
| 726 | address points to the textual address, checked for syntax |
| 727 | bin points to an array of 4 ints |
| 728 | |
| 729 | Returns: the number of ints used |
| 730 | */ |
| 731 | |
| 732 | int |
| 733 | host_aton(uschar *address, int *bin) |
| 734 | { |
| 735 | int x[4]; |
| 736 | int v4offset = 0; |
| 737 | |
| 738 | /* Handle IPv6 address, which may end with an IPv4 address. It may also end |
| 739 | with a "scope", introduced by a percent sign. This code is NOT enclosed in #if |
| 740 | HAVE_IPV6 in order that IPv6 addresses are recognized even if IPv6 is not |
| 741 | supported. */ |
| 742 | |
| 743 | if (Ustrchr(address, ':') != NULL) |
| 744 | { |
| 745 | uschar *p = address; |
| 746 | uschar *component[8]; |
| 747 | BOOL ipv4_ends = FALSE; |
| 748 | int ci = 0; |
| 749 | int nulloffset = 0; |
| 750 | int v6count = 8; |
| 751 | int i; |
| 752 | |
| 753 | /* If the address starts with a colon, it will start with two colons. |
| 754 | Just lose the first one, which will leave a null first component. */ |
| 755 | |
| 756 | if (*p == ':') p++; |
| 757 | |
| 758 | /* Split the address into components separated by colons. The input address |
| 759 | is supposed to be checked for syntax. There was a case where this was |
| 760 | overlooked; to guard against that happening again, check here and crash if |
| 761 | there are too many components. */ |
| 762 | |
| 763 | while (*p != 0 && *p != '%') |
| 764 | { |
| 765 | int len = Ustrcspn(p, ":%"); |
| 766 | if (len == 0) nulloffset = ci; |
| 767 | if (ci > 7) log_write(0, LOG_MAIN|LOG_PANIC_DIE, |
| 768 | "Internal error: invalid IPv6 address \"%s\" passed to host_aton()", |
| 769 | address); |
| 770 | component[ci++] = p; |
| 771 | p += len; |
| 772 | if (*p == ':') p++; |
| 773 | } |
| 774 | |
| 775 | /* If the final component contains a dot, it is a trailing v4 address. |
| 776 | As the syntax is known to be checked, just set up for a trailing |
| 777 | v4 address and restrict the v6 part to 6 components. */ |
| 778 | |
| 779 | if (Ustrchr(component[ci-1], '.') != NULL) |
| 780 | { |
| 781 | address = component[--ci]; |
| 782 | ipv4_ends = TRUE; |
| 783 | v4offset = 3; |
| 784 | v6count = 6; |
| 785 | } |
| 786 | |
| 787 | /* If there are fewer than 6 or 8 components, we have to insert some |
| 788 | more empty ones in the middle. */ |
| 789 | |
| 790 | if (ci < v6count) |
| 791 | { |
| 792 | int insert_count = v6count - ci; |
| 793 | for (i = v6count-1; i > nulloffset + insert_count; i--) |
| 794 | component[i] = component[i - insert_count]; |
| 795 | while (i > nulloffset) component[i--] = US""; |
| 796 | } |
| 797 | |
| 798 | /* Now turn the components into binary in pairs and bung them |
| 799 | into the vector of ints. */ |
| 800 | |
| 801 | for (i = 0; i < v6count; i += 2) |
| 802 | bin[i/2] = (Ustrtol(component[i], NULL, 16) << 16) + |
| 803 | Ustrtol(component[i+1], NULL, 16); |
| 804 | |
| 805 | /* If there was no terminating v4 component, we are done. */ |
| 806 | |
| 807 | if (!ipv4_ends) return 4; |
| 808 | } |
| 809 | |
| 810 | /* Handle IPv4 address */ |
| 811 | |
| 812 | sscanf(CS address, "%d.%d.%d.%d", x, x+1, x+2, x+3); |
| 813 | bin[v4offset] = (x[0] << 24) + (x[1] << 16) + (x[2] << 8) + x[3]; |
| 814 | return v4offset+1; |
| 815 | } |
| 816 | |
| 817 | |
| 818 | /************************************************* |
| 819 | * Apply mask to an IP address * |
| 820 | *************************************************/ |
| 821 | |
| 822 | /* Mask an address held in 1 or 4 ints, with the ms bit in the ms bit of the |
| 823 | first int, etc. |
| 824 | |
| 825 | Arguments: |
| 826 | count the number of ints |
| 827 | binary points to the ints to be masked |
| 828 | mask the count of ms bits to leave, or -1 if no masking |
| 829 | |
| 830 | Returns: nothing |
| 831 | */ |
| 832 | |
| 833 | void |
| 834 | host_mask(int count, int *binary, int mask) |
| 835 | { |
| 836 | int i; |
| 837 | if (mask < 0) mask = 99999; |
| 838 | for (i = 0; i < count; i++) |
| 839 | { |
| 840 | int wordmask; |
| 841 | if (mask == 0) wordmask = 0; |
| 842 | else if (mask < 32) |
| 843 | { |
| 844 | wordmask = (-1) << (32 - mask); |
| 845 | mask = 0; |
| 846 | } |
| 847 | else |
| 848 | { |
| 849 | wordmask = -1; |
| 850 | mask -= 32; |
| 851 | } |
| 852 | binary[i] &= wordmask; |
| 853 | } |
| 854 | } |
| 855 | |
| 856 | |
| 857 | |
| 858 | |
| 859 | /************************************************* |
| 860 | * Convert masked IP address in ints to text * |
| 861 | *************************************************/ |
| 862 | |
| 863 | /* We can't use host_ntoa() because it assumes the binary values are in network |
| 864 | byte order, and these are the result of host_aton(), which puts them in ints in |
| 865 | host byte order. Also, we really want IPv6 addresses to be in a canonical |
| 866 | format, so we output them with no abbreviation. In a number of cases we can't |
| 867 | use the normal colon separator in them because it terminates keys in lsearch |
| 868 | files, so we want to use dot instead. There's an argument that specifies what |
| 869 | to use for IPv6 addresses. |
| 870 | |
| 871 | Arguments: |
| 872 | count 1 or 4 (number of ints) |
| 873 | binary points to the ints |
| 874 | mask mask value; if < 0 don't add to result |
| 875 | buffer big enough to hold the result |
| 876 | sep component separator character for IPv6 addresses |
| 877 | |
| 878 | Returns: the number of characters placed in buffer, not counting |
| 879 | the final nul. |
| 880 | */ |
| 881 | |
| 882 | int |
| 883 | host_nmtoa(int count, int *binary, int mask, uschar *buffer, int sep) |
| 884 | { |
| 885 | int i, j; |
| 886 | uschar *tt = buffer; |
| 887 | |
| 888 | if (count == 1) |
| 889 | { |
| 890 | j = binary[0]; |
| 891 | for (i = 24; i >= 0; i -= 8) |
| 892 | { |
| 893 | sprintf(CS tt, "%d.", (j >> i) & 255); |
| 894 | while (*tt) tt++; |
| 895 | } |
| 896 | } |
| 897 | else |
| 898 | { |
| 899 | for (i = 0; i < 4; i++) |
| 900 | { |
| 901 | j = binary[i]; |
| 902 | sprintf(CS tt, "%04x%c%04x%c", (j >> 16) & 0xffff, sep, j & 0xffff, sep); |
| 903 | while (*tt) tt++; |
| 904 | } |
| 905 | } |
| 906 | |
| 907 | tt--; /* lose final separator */ |
| 908 | |
| 909 | if (mask < 0) |
| 910 | *tt = 0; |
| 911 | else |
| 912 | { |
| 913 | sprintf(CS tt, "/%d", mask); |
| 914 | while (*tt) tt++; |
| 915 | } |
| 916 | |
| 917 | return tt - buffer; |
| 918 | } |
| 919 | |
| 920 | |
| 921 | |
| 922 | /************************************************* |
| 923 | * Check port for tls_on_connect * |
| 924 | *************************************************/ |
| 925 | |
| 926 | /* This function checks whether a given incoming port is configured for tls- |
| 927 | on-connect. It is called from the daemon and from inetd handling. If the global |
| 928 | option tls_on_connect is already set, all ports operate this way. Otherwise, we |
| 929 | check the tls_on_connect_ports option for a list of ports. |
| 930 | |
| 931 | Argument: a port number |
| 932 | Returns: TRUE or FALSE |
| 933 | */ |
| 934 | |
| 935 | BOOL |
| 936 | host_is_tls_on_connect_port(int port) |
| 937 | { |
| 938 | int sep = 0; |
| 939 | uschar buffer[32]; |
| 940 | uschar *list = tls_on_connect_ports; |
| 941 | uschar *s; |
| 942 | |
| 943 | if (tls_on_connect) return TRUE; |
| 944 | |
| 945 | while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL) |
| 946 | { |
| 947 | uschar *end; |
| 948 | int lport = Ustrtol(s, &end, 10); |
| 949 | if (*end != 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "tls_on_connect_ports " |
| 950 | "contains \"%s\", which is not a port number: exim abandoned", s); |
| 951 | if (lport == port) return TRUE; |
| 952 | } |
| 953 | |
| 954 | return FALSE; |
| 955 | } |
| 956 | |
| 957 | |
| 958 | |
| 959 | /************************************************* |
| 960 | * Check whether host is in a network * |
| 961 | *************************************************/ |
| 962 | |
| 963 | /* This function checks whether a given IP address matches a pattern that |
| 964 | represents either a single host, or a network (using CIDR notation). The caller |
| 965 | of this function must check the syntax of the arguments before calling it. |
| 966 | |
| 967 | Arguments: |
| 968 | host string representation of the ip-address to check |
| 969 | net string representation of the network, with optional CIDR mask |
| 970 | maskoffset offset to the / that introduces the mask in the key |
| 971 | zero if there is no mask |
| 972 | |
| 973 | Returns: |
| 974 | TRUE the host is inside the network |
| 975 | FALSE the host is NOT inside the network |
| 976 | */ |
| 977 | |
| 978 | BOOL |
| 979 | host_is_in_net(uschar *host, uschar *net, int maskoffset) |
| 980 | { |
| 981 | int i; |
| 982 | int address[4]; |
| 983 | int incoming[4]; |
| 984 | int mlen; |
| 985 | int size = host_aton(net, address); |
| 986 | int insize; |
| 987 | |
| 988 | /* No mask => all bits to be checked */ |
| 989 | |
| 990 | if (maskoffset == 0) mlen = 99999; /* Big number */ |
| 991 | else mlen = Uatoi(net + maskoffset + 1); |
| 992 | |
| 993 | /* Convert the incoming address to binary. */ |
| 994 | |
| 995 | insize = host_aton(host, incoming); |
| 996 | |
| 997 | /* Convert IPv4 addresses given in IPv6 compatible mode, which represent |
| 998 | connections from IPv4 hosts to IPv6 hosts, that is, addresses of the form |
| 999 | ::ffff:<v4address>, to IPv4 format. */ |
| 1000 | |
| 1001 | if (insize == 4 && incoming[0] == 0 && incoming[1] == 0 && |
| 1002 | incoming[2] == 0xffff) |
| 1003 | { |
| 1004 | insize = 1; |
| 1005 | incoming[0] = incoming[3]; |
| 1006 | } |
| 1007 | |
| 1008 | /* No match if the sizes don't agree. */ |
| 1009 | |
| 1010 | if (insize != size) return FALSE; |
| 1011 | |
| 1012 | /* Else do the masked comparison. */ |
| 1013 | |
| 1014 | for (i = 0; i < size; i++) |
| 1015 | { |
| 1016 | int mask; |
| 1017 | if (mlen == 0) mask = 0; |
| 1018 | else if (mlen < 32) |
| 1019 | { |
| 1020 | mask = (-1) << (32 - mlen); |
| 1021 | mlen = 0; |
| 1022 | } |
| 1023 | else |
| 1024 | { |
| 1025 | mask = -1; |
| 1026 | mlen -= 32; |
| 1027 | } |
| 1028 | if ((incoming[i] & mask) != (address[i] & mask)) return FALSE; |
| 1029 | } |
| 1030 | |
| 1031 | return TRUE; |
| 1032 | } |
| 1033 | |
| 1034 | |
| 1035 | |
| 1036 | /************************************************* |
| 1037 | * Scan host list for local hosts * |
| 1038 | *************************************************/ |
| 1039 | |
| 1040 | /* Scan through a chain of addresses and check whether any of them is the |
| 1041 | address of an interface on the local machine. If so, remove that address and |
| 1042 | any previous ones with the same MX value, and all subsequent ones (which will |
| 1043 | have greater or equal MX values) from the chain. Note: marking them as unusable |
| 1044 | is NOT the right thing to do because it causes the hosts not to be used for |
| 1045 | other domains, for which they may well be correct. |
| 1046 | |
| 1047 | The hosts may be part of a longer chain; we only process those between the |
| 1048 | initial pointer and the "last" pointer. |
| 1049 | |
| 1050 | There is also a list of "pseudo-local" host names which are checked against the |
| 1051 | host names. Any match causes that host item to be treated the same as one which |
| 1052 | matches a local IP address. |
| 1053 | |
| 1054 | If the very first host is a local host, then all MX records had a precedence |
| 1055 | greater than or equal to that of the local host. Either there's a problem in |
| 1056 | the DNS, or an apparently remote name turned out to be an abbreviation for the |
| 1057 | local host. Give a specific return code, and let the caller decide what to do. |
| 1058 | Otherwise, give a success code if at least one host address has been found. |
| 1059 | |
| 1060 | Arguments: |
| 1061 | host pointer to the first host in the chain |
| 1062 | lastptr pointer to pointer to the last host in the chain (may be updated) |
| 1063 | removed if not NULL, set TRUE if some local addresses were removed |
| 1064 | from the list |
| 1065 | |
| 1066 | Returns: |
| 1067 | HOST_FOUND if there is at least one host with an IP address on the chain |
| 1068 | and an MX value less than any MX value associated with the |
| 1069 | local host |
| 1070 | HOST_FOUND_LOCAL if a local host is among the lowest-numbered MX hosts; when |
| 1071 | the host addresses were obtained from A records or |
| 1072 | gethostbyname(), the MX values are set to -1. |
| 1073 | HOST_FIND_FAILED if no valid hosts with set IP addresses were found |
| 1074 | */ |
| 1075 | |
| 1076 | int |
| 1077 | host_scan_for_local_hosts(host_item *host, host_item **lastptr, BOOL *removed) |
| 1078 | { |
| 1079 | int yield = HOST_FIND_FAILED; |
| 1080 | host_item *last = *lastptr; |
| 1081 | host_item *prev = NULL; |
| 1082 | host_item *h; |
| 1083 | |
| 1084 | if (removed != NULL) *removed = FALSE; |
| 1085 | |
| 1086 | if (local_interface_data == NULL) local_interface_data = host_find_interfaces(); |
| 1087 | |
| 1088 | for (h = host; h != last->next; h = h->next) |
| 1089 | { |
| 1090 | #ifndef STAND_ALONE |
| 1091 | if (hosts_treat_as_local != NULL) |
| 1092 | { |
| 1093 | int rc; |
| 1094 | uschar *save = deliver_domain; |
| 1095 | deliver_domain = h->name; /* set $domain */ |
| 1096 | rc = match_isinlist(string_copylc(h->name), &hosts_treat_as_local, 0, |
| 1097 | &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL); |
| 1098 | deliver_domain = save; |
| 1099 | if (rc == OK) goto FOUND_LOCAL; |
| 1100 | } |
| 1101 | #endif |
| 1102 | |
| 1103 | /* It seems that on many operating systems, 0.0.0.0 is treated as a synonym |
| 1104 | for 127.0.0.1 and refers to the local host. We therefore force it always to |
| 1105 | be treated as local. */ |
| 1106 | |
| 1107 | if (h->address != NULL) |
| 1108 | { |
| 1109 | ip_address_item *ip; |
| 1110 | if (Ustrcmp(h->address, "0.0.0.0") == 0) goto FOUND_LOCAL; |
| 1111 | for (ip = local_interface_data; ip != NULL; ip = ip->next) |
| 1112 | if (Ustrcmp(h->address, ip->address) == 0) goto FOUND_LOCAL; |
| 1113 | yield = HOST_FOUND; /* At least one remote address has been found */ |
| 1114 | } |
| 1115 | |
| 1116 | /* Update prev to point to the last host item before any that have |
| 1117 | the same MX value as the one we have just considered. */ |
| 1118 | |
| 1119 | if (h->next == NULL || h->next->mx != h->mx) prev = h; |
| 1120 | } |
| 1121 | |
| 1122 | return yield; /* No local hosts found: return HOST_FOUND or HOST_FIND_FAILED */ |
| 1123 | |
| 1124 | /* A host whose IP address matches a local IP address, or whose name matches |
| 1125 | something in hosts_treat_as_local has been found. */ |
| 1126 | |
| 1127 | FOUND_LOCAL: |
| 1128 | |
| 1129 | if (prev == NULL) |
| 1130 | { |
| 1131 | HDEBUG(D_host_lookup) debug_printf((h->mx >= 0)? |
| 1132 | "local host has lowest MX\n" : |
| 1133 | "local host found for non-MX address\n"); |
| 1134 | return HOST_FOUND_LOCAL; |
| 1135 | } |
| 1136 | |
| 1137 | HDEBUG(D_host_lookup) |
| 1138 | { |
| 1139 | debug_printf("local host in host list - removed hosts:\n"); |
| 1140 | for (h = prev->next; h != last->next; h = h->next) |
| 1141 | debug_printf(" %s %s %d\n", h->name, h->address, h->mx); |
| 1142 | } |
| 1143 | |
| 1144 | if (removed != NULL) *removed = TRUE; |
| 1145 | prev->next = last->next; |
| 1146 | *lastptr = prev; |
| 1147 | return yield; |
| 1148 | } |
| 1149 | |
| 1150 | |
| 1151 | |
| 1152 | |
| 1153 | /************************************************* |
| 1154 | * Remove duplicate IPs in host list * |
| 1155 | *************************************************/ |
| 1156 | |
| 1157 | /* You would think that administrators could set up their DNS records so that |
| 1158 | one ended up with a list of unique IP addresses after looking up A or MX |
| 1159 | records, but apparently duplication is common. So we scan such lists and |
| 1160 | remove the later duplicates. Note that we may get lists in which some host |
| 1161 | addresses are not set. |
| 1162 | |
| 1163 | Arguments: |
| 1164 | host pointer to the first host in the chain |
| 1165 | lastptr pointer to pointer to the last host in the chain (may be updated) |
| 1166 | |
| 1167 | Returns: nothing |
| 1168 | */ |
| 1169 | |
| 1170 | static void |
| 1171 | host_remove_duplicates(host_item *host, host_item **lastptr) |
| 1172 | { |
| 1173 | while (host != *lastptr) |
| 1174 | { |
| 1175 | if (host->address != NULL) |
| 1176 | { |
| 1177 | host_item *h = host; |
| 1178 | while (h != *lastptr) |
| 1179 | { |
| 1180 | if (h->next->address != NULL && |
| 1181 | Ustrcmp(h->next->address, host->address) == 0) |
| 1182 | { |
| 1183 | DEBUG(D_host_lookup) debug_printf("duplicate IP address %s (MX=%d) " |
| 1184 | "removed\n", host->address, h->next->mx); |
| 1185 | if (h->next == *lastptr) *lastptr = h; |
| 1186 | h->next = h->next->next; |
| 1187 | } |
| 1188 | else h = h->next; |
| 1189 | } |
| 1190 | } |
| 1191 | /* If the last item was removed, host may have become == *lastptr */ |
| 1192 | if (host != *lastptr) host = host->next; |
| 1193 | } |
| 1194 | } |
| 1195 | |
| 1196 | |
| 1197 | |
| 1198 | |
| 1199 | /************************************************* |
| 1200 | * Find sender host name by gethostbyaddr() * |
| 1201 | *************************************************/ |
| 1202 | |
| 1203 | /* This used to be the only way it was done, but it turns out that not all |
| 1204 | systems give aliases for calls to gethostbyaddr() - or one of the modern |
| 1205 | equivalents like getipnodebyaddr(). Fortunately, multiple PTR records are rare, |
| 1206 | but they can still exist. This function is now used only when a DNS lookup of |
| 1207 | the IP address fails, in order to give access to /etc/hosts. |
| 1208 | |
| 1209 | Arguments: none |
| 1210 | Returns: OK, DEFER, FAIL |
| 1211 | */ |
| 1212 | |
| 1213 | static int |
| 1214 | host_name_lookup_byaddr(void) |
| 1215 | { |
| 1216 | int len; |
| 1217 | uschar *s, *t; |
| 1218 | struct hostent *hosts; |
| 1219 | struct in_addr addr; |
| 1220 | |
| 1221 | /* Lookup on IPv6 system */ |
| 1222 | |
| 1223 | #if HAVE_IPV6 |
| 1224 | if (Ustrchr(sender_host_address, ':') != NULL) |
| 1225 | { |
| 1226 | struct in6_addr addr6; |
| 1227 | if (inet_pton(AF_INET6, CS sender_host_address, &addr6) != 1) |
| 1228 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an " |
| 1229 | "IPv6 address", sender_host_address); |
| 1230 | #if HAVE_GETIPNODEBYADDR |
| 1231 | hosts = getipnodebyaddr(CS &addr6, sizeof(addr6), AF_INET6, &h_errno); |
| 1232 | #else |
| 1233 | hosts = gethostbyaddr(CS &addr6, sizeof(addr6), AF_INET6); |
| 1234 | #endif |
| 1235 | } |
| 1236 | else |
| 1237 | { |
| 1238 | if (inet_pton(AF_INET, CS sender_host_address, &addr) != 1) |
| 1239 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an " |
| 1240 | "IPv4 address", sender_host_address); |
| 1241 | #if HAVE_GETIPNODEBYADDR |
| 1242 | hosts = getipnodebyaddr(CS &addr, sizeof(addr), AF_INET, &h_errno); |
| 1243 | #else |
| 1244 | hosts = gethostbyaddr(CS &addr, sizeof(addr), AF_INET); |
| 1245 | #endif |
| 1246 | } |
| 1247 | |
| 1248 | /* Do lookup on IPv4 system */ |
| 1249 | |
| 1250 | #else |
| 1251 | addr.s_addr = (S_ADDR_TYPE)inet_addr(CS sender_host_address); |
| 1252 | hosts = gethostbyaddr(CS(&addr), sizeof(addr), AF_INET); |
| 1253 | #endif |
| 1254 | |
| 1255 | /* Failed to look up the host. */ |
| 1256 | |
| 1257 | if (hosts == NULL) |
| 1258 | { |
| 1259 | HDEBUG(D_host_lookup) debug_printf("IP address lookup failed: h_errno=%d\n", |
| 1260 | h_errno); |
| 1261 | return (h_errno == TRY_AGAIN || h_errno == NO_RECOVERY) ? DEFER : FAIL; |
| 1262 | } |
| 1263 | |
| 1264 | /* It seems there are some records in the DNS that yield an empty name. We |
| 1265 | treat this as non-existent. In some operating systems, this is returned as an |
| 1266 | empty string; in others as a single dot. */ |
| 1267 | |
| 1268 | if (hosts->h_name[0] == 0 || hosts->h_name[0] == '.') |
| 1269 | { |
| 1270 | HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: " |
| 1271 | "treated as non-existent host name\n"); |
| 1272 | return FAIL; |
| 1273 | } |
| 1274 | |
| 1275 | /* Copy and lowercase the name, which is in static storage in many systems. |
| 1276 | Put it in permanent memory. */ |
| 1277 | |
| 1278 | s = (uschar *)hosts->h_name; |
| 1279 | len = Ustrlen(s) + 1; |
| 1280 | t = sender_host_name = store_get_perm(len); |
| 1281 | while (*s != 0) *t++ = tolower(*s++); |
| 1282 | *t = 0; |
| 1283 | |
| 1284 | /* If the host has aliases, build a copy of the alias list */ |
| 1285 | |
| 1286 | if (hosts->h_aliases != NULL) |
| 1287 | { |
| 1288 | int count = 1; |
| 1289 | uschar **aliases, **ptr; |
| 1290 | for (aliases = USS hosts->h_aliases; *aliases != NULL; aliases++) count++; |
| 1291 | ptr = sender_host_aliases = store_get_perm(count * sizeof(uschar *)); |
| 1292 | for (aliases = USS hosts->h_aliases; *aliases != NULL; aliases++) |
| 1293 | { |
| 1294 | uschar *s = *aliases; |
| 1295 | int len = Ustrlen(s) + 1; |
| 1296 | uschar *t = *ptr++ = store_get_perm(len); |
| 1297 | while (*s != 0) *t++ = tolower(*s++); |
| 1298 | *t = 0; |
| 1299 | } |
| 1300 | *ptr = NULL; |
| 1301 | } |
| 1302 | |
| 1303 | return OK; |
| 1304 | } |
| 1305 | |
| 1306 | |
| 1307 | |
| 1308 | /************************************************* |
| 1309 | * Find host name for incoming call * |
| 1310 | *************************************************/ |
| 1311 | |
| 1312 | /* Put the name in permanent store, pointed to by sender_host_name. We also set |
| 1313 | up a list of alias names, pointed to by sender_host_alias. The list is |
| 1314 | NULL-terminated. The incoming address is in sender_host_address, either in |
| 1315 | dotted-quad form for IPv4 or in colon-separated form for IPv6. |
| 1316 | |
| 1317 | This function does a thorough check that the names it finds point back to the |
| 1318 | incoming IP address. Any that do not are discarded. Note that this is relied on |
| 1319 | by the ACL reverse_host_lookup check. |
| 1320 | |
| 1321 | On some systems, get{host,ipnode}byaddr() appears to do this internally, but |
| 1322 | this it not universally true. Also, for release 4.30, this function was changed |
| 1323 | to do a direct DNS lookup first, by default[1], because it turns out that that |
| 1324 | is the only guaranteed way to find all the aliases on some systems. My |
| 1325 | experiments indicate that Solaris gethostbyaddr() gives the aliases for but |
| 1326 | Linux does not. |
| 1327 | |
| 1328 | [1] The actual order is controlled by the host_lookup_order option. |
| 1329 | |
| 1330 | Arguments: none |
| 1331 | Returns: OK on success, the answer being placed in the global variable |
| 1332 | sender_host_name, with any aliases in a list hung off |
| 1333 | sender_host_aliases |
| 1334 | FAIL if no host name can be found |
| 1335 | DEFER if a temporary error was encountered |
| 1336 | |
| 1337 | The variable host_lookup_msg is set to an empty string on sucess, or to a |
| 1338 | reason for the failure otherwise, in a form suitable for tagging onto an error |
| 1339 | message, and also host_lookup_failed is set TRUE if the lookup failed. If there |
| 1340 | was a defer, host_lookup_deferred is set TRUE. |
| 1341 | |
| 1342 | Any dynamically constructed string for host_lookup_msg must be in permanent |
| 1343 | store, because it might be used for several incoming messages on the same SMTP |
| 1344 | connection. */ |
| 1345 | |
| 1346 | int |
| 1347 | host_name_lookup(void) |
| 1348 | { |
| 1349 | int old_pool, rc; |
| 1350 | int sep = 0; |
| 1351 | uschar *hname, *save_hostname; |
| 1352 | uschar **aliases; |
| 1353 | uschar buffer[256]; |
| 1354 | uschar *ordername; |
| 1355 | uschar *list = host_lookup_order; |
| 1356 | dns_record *rr; |
| 1357 | dns_answer dnsa; |
| 1358 | dns_scan dnss; |
| 1359 | |
| 1360 | host_lookup_deferred = host_lookup_failed = FALSE; |
| 1361 | |
| 1362 | HDEBUG(D_host_lookup) |
| 1363 | debug_printf("looking up host name for %s\n", sender_host_address); |
| 1364 | |
| 1365 | /* For testing the case when a lookup does not complete, we have a special |
| 1366 | reserved IP address. */ |
| 1367 | |
| 1368 | if (running_in_test_harness && |
| 1369 | Ustrcmp(sender_host_address, "99.99.99.99") == 0) |
| 1370 | { |
| 1371 | HDEBUG(D_host_lookup) |
| 1372 | debug_printf("Test harness: host name lookup returns DEFER\n"); |
| 1373 | host_lookup_deferred = TRUE; |
| 1374 | return DEFER; |
| 1375 | } |
| 1376 | |
| 1377 | /* Do lookups directly in the DNS or via gethostbyaddr() (or equivalent), in |
| 1378 | the order specified by the host_lookup_order option. */ |
| 1379 | |
| 1380 | while ((ordername = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) |
| 1381 | != NULL) |
| 1382 | { |
| 1383 | if (strcmpic(ordername, US"bydns") == 0) |
| 1384 | { |
| 1385 | dns_init(FALSE, FALSE); |
| 1386 | dns_build_reverse(sender_host_address, buffer); |
| 1387 | rc = dns_lookup(&dnsa, buffer, T_PTR, NULL); |
| 1388 | |
| 1389 | /* The first record we come across is used for the name; others are |
| 1390 | considered to be aliases. We have to scan twice, in order to find out the |
| 1391 | number of aliases. However, if all the names are empty, we will behave as |
| 1392 | if failure. (PTR records that yield empty names have been encountered in |
| 1393 | the DNS.) */ |
| 1394 | |
| 1395 | if (rc == DNS_SUCCEED) |
| 1396 | { |
| 1397 | uschar **aptr = NULL; |
| 1398 | int ssize = 264; |
| 1399 | int count = 0; |
| 1400 | int old_pool = store_pool; |
| 1401 | |
| 1402 | store_pool = POOL_PERM; /* Save names in permanent storage */ |
| 1403 | |
| 1404 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
| 1405 | rr != NULL; |
| 1406 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) |
| 1407 | { |
| 1408 | if (rr->type == T_PTR) count++; |
| 1409 | } |
| 1410 | |
| 1411 | /* Get store for the list of aliases. For compatibility with |
| 1412 | gethostbyaddr, we make an empty list if there are none. */ |
| 1413 | |
| 1414 | aptr = sender_host_aliases = store_get(count * sizeof(uschar *)); |
| 1415 | |
| 1416 | /* Re-scan and extract the names */ |
| 1417 | |
| 1418 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
| 1419 | rr != NULL; |
| 1420 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) |
| 1421 | { |
| 1422 | uschar *s = NULL; |
| 1423 | if (rr->type != T_PTR) continue; |
| 1424 | s = store_get(ssize); |
| 1425 | |
| 1426 | /* If an overlong response was received, the data will have been |
| 1427 | truncated and dn_expand may fail. */ |
| 1428 | |
| 1429 | if (dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, |
| 1430 | (uschar *)(rr->data), (DN_EXPAND_ARG4_TYPE)(s), ssize) < 0) |
| 1431 | { |
| 1432 | log_write(0, LOG_MAIN, "host name alias list truncated for %s", |
| 1433 | sender_host_address); |
| 1434 | break; |
| 1435 | } |
| 1436 | |
| 1437 | store_reset(s + Ustrlen(s) + 1); |
| 1438 | if (s[0] == 0) |
| 1439 | { |
| 1440 | HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an " |
| 1441 | "empty name: treated as non-existent host name\n"); |
| 1442 | continue; |
| 1443 | } |
| 1444 | if (sender_host_name == NULL) sender_host_name = s; |
| 1445 | else *aptr++ = s; |
| 1446 | while (*s != 0) { *s = tolower(*s); s++; } |
| 1447 | } |
| 1448 | |
| 1449 | *aptr = NULL; /* End of alias list */ |
| 1450 | store_pool = old_pool; /* Reset store pool */ |
| 1451 | |
| 1452 | /* If we've found a names, break out of the "order" loop */ |
| 1453 | |
| 1454 | if (sender_host_name != NULL) break; |
| 1455 | } |
| 1456 | |
| 1457 | /* If the DNS lookup deferred, we must also defer. */ |
| 1458 | |
| 1459 | if (rc == DNS_AGAIN) |
| 1460 | { |
| 1461 | HDEBUG(D_host_lookup) |
| 1462 | debug_printf("IP address PTR lookup gave temporary error\n"); |
| 1463 | host_lookup_deferred = TRUE; |
| 1464 | return DEFER; |
| 1465 | } |
| 1466 | } |
| 1467 | |
| 1468 | /* Do a lookup using gethostbyaddr() - or equivalent */ |
| 1469 | |
| 1470 | else if (strcmpic(ordername, US"byaddr") == 0) |
| 1471 | { |
| 1472 | HDEBUG(D_host_lookup) |
| 1473 | debug_printf("IP address lookup using gethostbyaddr()\n"); |
| 1474 | rc = host_name_lookup_byaddr(); |
| 1475 | if (rc == DEFER) |
| 1476 | { |
| 1477 | host_lookup_deferred = TRUE; |
| 1478 | return rc; /* Can't carry on */ |
| 1479 | } |
| 1480 | if (rc == OK) break; /* Found a name */ |
| 1481 | } |
| 1482 | } /* Loop for bydns/byaddr scanning */ |
| 1483 | |
| 1484 | /* If we have failed to find a name, return FAIL and log when required. |
| 1485 | NB host_lookup_msg must be in permanent store. */ |
| 1486 | |
| 1487 | if (sender_host_name == NULL) |
| 1488 | { |
| 1489 | if (host_checking || !log_testing_mode) |
| 1490 | log_write(L_host_lookup_failed, LOG_MAIN, "no host name found for IP " |
| 1491 | "address %s", sender_host_address); |
| 1492 | host_lookup_msg = US" (failed to find host name from IP address)"; |
| 1493 | host_lookup_failed = TRUE; |
| 1494 | return FAIL; |
| 1495 | } |
| 1496 | |
| 1497 | /* We have a host name. If we are running in the test harness, we want the host |
| 1498 | name and its alias to appear always the same way round. There are only ever two |
| 1499 | names in these tests. If one of them contains "alias", make sure it is second; |
| 1500 | otherwise put them in alphabetical order. */ |
| 1501 | |
| 1502 | if (running_in_test_harness && *sender_host_aliases != NULL && |
| 1503 | ( |
| 1504 | Ustrstr(sender_host_name, "alias") != NULL || |
| 1505 | ( |
| 1506 | Ustrstr(*sender_host_aliases, "alias") == NULL && |
| 1507 | Ustrcmp(sender_host_name, *sender_host_aliases) > 0 |
| 1508 | ) |
| 1509 | )) |
| 1510 | { |
| 1511 | uschar *temp = sender_host_name; |
| 1512 | sender_host_name = *sender_host_aliases; |
| 1513 | *sender_host_aliases = temp; |
| 1514 | } |
| 1515 | |
| 1516 | /* Debug output what was found, after test harness swapping, for consistency */ |
| 1517 | |
| 1518 | HDEBUG(D_host_lookup) |
| 1519 | { |
| 1520 | uschar **aliases = sender_host_aliases; |
| 1521 | debug_printf("IP address lookup yielded %s\n", sender_host_name); |
| 1522 | while (*aliases != NULL) debug_printf(" alias %s\n", *aliases++); |
| 1523 | } |
| 1524 | |
| 1525 | /* We need to verify that a forward lookup on the name we found does indeed |
| 1526 | correspond to the address. This is for security: in principle a malefactor who |
| 1527 | happened to own a reverse zone could set it to point to any names at all. |
| 1528 | |
| 1529 | This code was present in versions of Exim before 3.20. At that point I took it |
| 1530 | out because I thought that gethostbyaddr() did the check anyway. It turns out |
| 1531 | that this isn't always the case, so it's coming back in at 4.01. This version |
| 1532 | is actually better, because it also checks aliases. |
| 1533 | |
| 1534 | The code was made more robust at release 4.21. Prior to that, it accepted all |
| 1535 | the names if any of them had the correct IP address. Now the code checks all |
| 1536 | the names, and accepts only those that have the correct IP address. */ |
| 1537 | |
| 1538 | save_hostname = sender_host_name; /* Save for error messages */ |
| 1539 | aliases = sender_host_aliases; |
| 1540 | for (hname = sender_host_name; hname != NULL; hname = *aliases++) |
| 1541 | { |
| 1542 | int rc; |
| 1543 | BOOL ok = FALSE; |
| 1544 | host_item h; |
| 1545 | h.next = NULL; |
| 1546 | h.name = hname; |
| 1547 | h.mx = MX_NONE; |
| 1548 | h.address = NULL; |
| 1549 | |
| 1550 | /* When called with the 5th argument FALSE, host_find_byname() won't return |
| 1551 | HOST_FOUND_LOCAL. If the incoming address is an IPv4 address expressed in |
| 1552 | IPv6 format, we must compare the IPv4 part to any IPv4 addresses. */ |
| 1553 | |
| 1554 | if ((rc = host_find_byname(&h, NULL, NULL, FALSE)) == HOST_FOUND) |
| 1555 | { |
| 1556 | host_item *hh; |
| 1557 | uschar *address_ipv4 = (Ustrncmp(sender_host_address, "::ffff:", 7) == 0)? |
| 1558 | sender_host_address + 7 : sender_host_address; |
| 1559 | HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname); |
| 1560 | for (hh = &h; hh != NULL; hh = hh->next) |
| 1561 | { |
| 1562 | if ((Ustrcmp(hh->address, (Ustrchr(hh->address, ':') == NULL)? |
| 1563 | address_ipv4 : sender_host_address)) == 0) |
| 1564 | { |
| 1565 | HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address); |
| 1566 | ok = TRUE; |
| 1567 | break; |
| 1568 | } |
| 1569 | else |
| 1570 | { |
| 1571 | HDEBUG(D_host_lookup) debug_printf(" %s\n", hh->address); |
| 1572 | } |
| 1573 | } |
| 1574 | if (!ok) HDEBUG(D_host_lookup) |
| 1575 | debug_printf("no IP address for %s matched %s\n", hname, |
| 1576 | sender_host_address); |
| 1577 | } |
| 1578 | else if (rc == HOST_FIND_AGAIN) |
| 1579 | { |
| 1580 | HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n"); |
| 1581 | host_lookup_deferred = TRUE; |
| 1582 | return DEFER; |
| 1583 | } |
| 1584 | else |
| 1585 | { |
| 1586 | HDEBUG(D_host_lookup) debug_printf("no IP addresses found for %s\n", hname); |
| 1587 | } |
| 1588 | |
| 1589 | /* If this name is no good, and it's the sender name, set it null pro tem; |
| 1590 | if it's an alias, just remove it from the list. */ |
| 1591 | |
| 1592 | if (!ok) |
| 1593 | { |
| 1594 | if (hname == sender_host_name) sender_host_name = NULL; else |
| 1595 | { |
| 1596 | uschar **a; /* Don't amalgamate - some */ |
| 1597 | a = --aliases; /* compilers grumble */ |
| 1598 | while (*a != NULL) { *a = a[1]; a++; } |
| 1599 | } |
| 1600 | } |
| 1601 | } |
| 1602 | |
| 1603 | /* If sender_host_name == NULL, it means we didn't like the name. Replace |
| 1604 | it with the first alias, if there is one. */ |
| 1605 | |
| 1606 | if (sender_host_name == NULL && *sender_host_aliases != NULL) |
| 1607 | sender_host_name = *sender_host_aliases++; |
| 1608 | |
| 1609 | /* If we now have a main name, all is well. */ |
| 1610 | |
| 1611 | if (sender_host_name != NULL) return OK; |
| 1612 | |
| 1613 | /* We have failed to find an address that matches. */ |
| 1614 | |
| 1615 | HDEBUG(D_host_lookup) |
| 1616 | debug_printf("%s does not match any IP address for %s\n", |
| 1617 | sender_host_address, save_hostname); |
| 1618 | |
| 1619 | /* This message must be in permanent store */ |
| 1620 | |
| 1621 | old_pool = store_pool; |
| 1622 | store_pool = POOL_PERM; |
| 1623 | host_lookup_msg = string_sprintf(" (%s does not match any IP address for %s)", |
| 1624 | sender_host_address, save_hostname); |
| 1625 | store_pool = old_pool; |
| 1626 | host_lookup_failed = TRUE; |
| 1627 | return FAIL; |
| 1628 | } |
| 1629 | |
| 1630 | |
| 1631 | |
| 1632 | |
| 1633 | /************************************************* |
| 1634 | * Find IP address(es) for host by name * |
| 1635 | *************************************************/ |
| 1636 | |
| 1637 | /* The input is a host_item structure with the name filled in and the address |
| 1638 | field set to NULL. We use gethostbyname(). Of course, gethostbyname() may use |
| 1639 | the DNS, but it doesn't do MX processing. If more than one address is given, |
| 1640 | chain on additional host items, with other relevant fields copied. |
| 1641 | |
| 1642 | The second argument provides a host list (usually an IP list) of hosts to |
| 1643 | ignore. This makes it possible to ignore IPv6 link-local addresses or loopback |
| 1644 | addresses in unreasonable places. |
| 1645 | |
| 1646 | The lookup may result in a change of name. For compatibility with the dns |
| 1647 | lookup, return this via fully_qualified_name as well as updating the host item. |
| 1648 | The lookup may also yield more than one IP address, in which case chain on |
| 1649 | subsequent host_item structures. |
| 1650 | |
| 1651 | Arguments: |
| 1652 | host a host item with the name and MX filled in; |
| 1653 | the address is to be filled in; |
| 1654 | multiple IP addresses cause other host items to be |
| 1655 | chained on. |
| 1656 | ignore_target_hosts a list of hosts to ignore |
| 1657 | fully_qualified_name if not NULL, set to point to host name for |
| 1658 | compatibility with host_find_bydns |
| 1659 | local_host_check TRUE if a check for the local host is wanted |
| 1660 | |
| 1661 | Returns: HOST_FIND_FAILED Failed to find the host or domain |
| 1662 | HOST_FIND_AGAIN Try again later |
| 1663 | HOST_FOUND Host found - data filled in |
| 1664 | HOST_FOUND_LOCAL Host found and is the local host |
| 1665 | */ |
| 1666 | |
| 1667 | int |
| 1668 | host_find_byname(host_item *host, uschar *ignore_target_hosts, |
| 1669 | uschar **fully_qualified_name, BOOL local_host_check) |
| 1670 | { |
| 1671 | int i, yield, times; |
| 1672 | uschar **addrlist; |
| 1673 | host_item *last = NULL; |
| 1674 | BOOL temp_error = FALSE; |
| 1675 | #if HAVE_IPV6 |
| 1676 | int af; |
| 1677 | #endif |
| 1678 | |
| 1679 | /* If we are in the test harness, a name ending in .test.again.dns always |
| 1680 | forces a temporary error response. */ |
| 1681 | |
| 1682 | if (running_in_test_harness) |
| 1683 | { |
| 1684 | uschar *endname = host->name + Ustrlen(host->name); |
| 1685 | if (Ustrcmp(endname - 14, "test.again.dns") == 0) |
| 1686 | return HOST_FIND_AGAIN; |
| 1687 | } |
| 1688 | |
| 1689 | /* In an IPv6 world, we need to scan for both kinds of address, so go round the |
| 1690 | loop twice. Note that we have ensured that AF_INET6 is defined even in an IPv4 |
| 1691 | world, which makes for slightly tidier code. However, if dns_ipv4_lookup |
| 1692 | matches the domain, we also just do IPv4 lookups here (except when testing |
| 1693 | standalone). */ |
| 1694 | |
| 1695 | #if HAVE_IPV6 |
| 1696 | #ifndef STAND_ALONE |
| 1697 | if (dns_ipv4_lookup != NULL && |
| 1698 | match_isinlist(host->name, &dns_ipv4_lookup, 0, NULL, NULL, MCL_DOMAIN, |
| 1699 | TRUE, NULL) == OK) |
| 1700 | { af = AF_INET; times = 1; } |
| 1701 | else |
| 1702 | #endif /* STAND_ALONE */ |
| 1703 | |
| 1704 | { af = AF_INET6; times = 2; } |
| 1705 | |
| 1706 | /* No IPv6 support */ |
| 1707 | |
| 1708 | #else /* HAVE_IPV6 */ |
| 1709 | times = 1; |
| 1710 | #endif /* HAVE_IPV6 */ |
| 1711 | |
| 1712 | /* Initialize the flag that gets set for DNS syntax check errors, so that the |
| 1713 | interface to this function can be similar to host_find_bydns. */ |
| 1714 | |
| 1715 | host_find_failed_syntax = FALSE; |
| 1716 | |
| 1717 | /* Loop to look up both kinds of address in an IPv6 world */ |
| 1718 | |
| 1719 | for (i = 1; i <= times; |
| 1720 | #if HAVE_IPV6 |
| 1721 | af = AF_INET, /* If 2 passes, IPv4 on the second */ |
| 1722 | #endif |
| 1723 | i++) |
| 1724 | { |
| 1725 | BOOL ipv4_addr; |
| 1726 | int error_num; |
| 1727 | struct hostent *hostdata; |
| 1728 | |
| 1729 | #if HAVE_IPV6 |
| 1730 | #if HAVE_GETIPNODEBYNAME |
| 1731 | hostdata = getipnodebyname(CS host->name, af, 0, &error_num); |
| 1732 | #else |
| 1733 | hostdata = gethostbyname2(CS host->name, af); |
| 1734 | error_num = h_errno; |
| 1735 | #endif |
| 1736 | #else |
| 1737 | hostdata = gethostbyname(CS host->name); |
| 1738 | error_num = h_errno; |
| 1739 | #endif |
| 1740 | |
| 1741 | if (hostdata == NULL) |
| 1742 | { |
| 1743 | uschar *error; |
| 1744 | switch (error_num) |
| 1745 | { |
| 1746 | case HOST_NOT_FOUND: error = US"HOST_NOT_FOUND"; break; |
| 1747 | case TRY_AGAIN: error = US"TRY_AGAIN"; break; |
| 1748 | case NO_RECOVERY: error = US"NO_RECOVERY"; break; |
| 1749 | case NO_DATA: error = US"NO_DATA"; break; |
| 1750 | #if NO_DATA != NO_ADDRESS |
| 1751 | case NO_ADDRESS: error = US"NO_ADDRESS"; break; |
| 1752 | #endif |
| 1753 | default: error = US"?"; break; |
| 1754 | } |
| 1755 | |
| 1756 | DEBUG(D_host_lookup) debug_printf("%s returned %d (%s)\n", |
| 1757 | #if HAVE_IPV6 |
| 1758 | #if HAVE_GETIPNODEBYNAME |
| 1759 | (af == AF_INET6)? "getipnodebyname(af=inet6)" : "getipnodebyname(af=inet)", |
| 1760 | #else |
| 1761 | (af == AF_INET6)? "gethostbyname2(af=inet6)" : "gethostbyname2(af=inet)", |
| 1762 | #endif |
| 1763 | #else |
| 1764 | "gethostbyname", |
| 1765 | #endif |
| 1766 | error_num, error); |
| 1767 | |
| 1768 | if (error_num == TRY_AGAIN || error_num == NO_RECOVERY) temp_error = TRUE; |
| 1769 | continue; |
| 1770 | } |
| 1771 | if ((hostdata->h_addr_list)[0] == NULL) continue; |
| 1772 | |
| 1773 | /* Replace the name with the fully qualified one if necessary, and fill in |
| 1774 | the fully_qualified_name pointer. */ |
| 1775 | |
| 1776 | if (hostdata->h_name[0] != 0 && |
| 1777 | Ustrcmp(host->name, hostdata->h_name) != 0) |
| 1778 | host->name = string_copy_dnsdomain((uschar *)hostdata->h_name); |
| 1779 | if (fully_qualified_name != NULL) *fully_qualified_name = host->name; |
| 1780 | |
| 1781 | /* Get the list of addresses. IPv4 and IPv6 addresses can be distinguished |
| 1782 | by their different lengths. Scan the list, ignoring any that are to be |
| 1783 | ignored, and build a chain from the rest. */ |
| 1784 | |
| 1785 | ipv4_addr = hostdata->h_length == sizeof(struct in_addr); |
| 1786 | |
| 1787 | for (addrlist = USS hostdata->h_addr_list; *addrlist != NULL; addrlist++) |
| 1788 | { |
| 1789 | uschar *text_address = |
| 1790 | host_ntoa(ipv4_addr? AF_INET:AF_INET6, *addrlist, NULL, NULL); |
| 1791 | |
| 1792 | #ifndef STAND_ALONE |
| 1793 | if (ignore_target_hosts != NULL && |
| 1794 | verify_check_this_host(&ignore_target_hosts, NULL, host->name, |
| 1795 | text_address, NULL) == OK) |
| 1796 | { |
| 1797 | DEBUG(D_host_lookup) |
| 1798 | debug_printf("ignored host %s [%s]\n", host->name, text_address); |
| 1799 | continue; |
| 1800 | } |
| 1801 | #endif |
| 1802 | |
| 1803 | /* If this is the first address, last == NULL and we put the data in the |
| 1804 | original block. */ |
| 1805 | |
| 1806 | if (last == NULL) |
| 1807 | { |
| 1808 | host->address = text_address; |
| 1809 | host->port = PORT_NONE; |
| 1810 | host->status = hstatus_unknown; |
| 1811 | host->why = hwhy_unknown; |
| 1812 | last = host; |
| 1813 | } |
| 1814 | |
| 1815 | /* Else add further host item blocks for any other addresses, keeping |
| 1816 | the order. */ |
| 1817 | |
| 1818 | else |
| 1819 | { |
| 1820 | host_item *next = store_get(sizeof(host_item)); |
| 1821 | next->name = host->name; |
| 1822 | next->mx = host->mx; |
| 1823 | next->address = text_address; |
| 1824 | next->port = PORT_NONE; |
| 1825 | next->status = hstatus_unknown; |
| 1826 | next->why = hwhy_unknown; |
| 1827 | next->last_try = 0; |
| 1828 | next->next = last->next; |
| 1829 | last->next = next; |
| 1830 | last = next; |
| 1831 | } |
| 1832 | } |
| 1833 | } |
| 1834 | |
| 1835 | /* If no hosts were found, the address field in the original host block will be |
| 1836 | NULL. If temp_error is set, at least one of the lookups gave a temporary error, |
| 1837 | so we pass that back. */ |
| 1838 | |
| 1839 | if (host->address == NULL) |
| 1840 | { |
| 1841 | uschar *msg = |
| 1842 | #ifndef STAND_ALONE |
| 1843 | (message_id[0] == 0 && smtp_in != NULL)? |
| 1844 | string_sprintf("no IP address found for host %s (during %s)", host->name, |
| 1845 | smtp_get_connection_info()) : |
| 1846 | #endif |
| 1847 | string_sprintf("no IP address found for host %s", host->name); |
| 1848 | |
| 1849 | HDEBUG(D_host_lookup) debug_printf("%s\n", msg); |
| 1850 | if (temp_error) return HOST_FIND_AGAIN; |
| 1851 | if (host_checking || !log_testing_mode) |
| 1852 | log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg); |
| 1853 | return HOST_FIND_FAILED; |
| 1854 | } |
| 1855 | |
| 1856 | /* Remove any duplicate IP addresses, then check to see if this is the local |
| 1857 | host if required. */ |
| 1858 | |
| 1859 | host_remove_duplicates(host, &last); |
| 1860 | yield = local_host_check? |
| 1861 | host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND; |
| 1862 | |
| 1863 | /* When running in the test harness, sort into the order of addresses so as to |
| 1864 | get repeatability. */ |
| 1865 | |
| 1866 | if (running_in_test_harness) sort_addresses(host, last); |
| 1867 | |
| 1868 | HDEBUG(D_host_lookup) |
| 1869 | { |
| 1870 | host_item *h; |
| 1871 | if (fully_qualified_name != NULL) |
| 1872 | debug_printf("fully qualified name = %s\n", *fully_qualified_name); |
| 1873 | debug_printf("%s looked up these IP addresses:\n", |
| 1874 | #if HAVE_IPV6 |
| 1875 | #if HAVE_GETIPNODEBYNAME |
| 1876 | "getipnodebyname" |
| 1877 | #else |
| 1878 | "gethostbyname2" |
| 1879 | #endif |
| 1880 | #else |
| 1881 | "gethostbyname" |
| 1882 | #endif |
| 1883 | ); |
| 1884 | for (h = host; h != last->next; h = h->next) |
| 1885 | debug_printf(" name=%s address=%s\n", h->name, |
| 1886 | (h->address == NULL)? US"<null>" : h->address); |
| 1887 | } |
| 1888 | |
| 1889 | /* Return the found status. */ |
| 1890 | |
| 1891 | return yield; |
| 1892 | } |
| 1893 | |
| 1894 | |
| 1895 | |
| 1896 | /************************************************* |
| 1897 | * Fill in a host address from the DNS * |
| 1898 | *************************************************/ |
| 1899 | |
| 1900 | /* Given a host item, with its name and mx fields set, and its address field |
| 1901 | set to NULL, fill in its IP address from the DNS. If it is multi-homed, create |
| 1902 | additional host items for the additional addresses, copying all the other |
| 1903 | fields, and randomizing the order. |
| 1904 | |
| 1905 | On IPv6 systems, A6 records are sought first (but only if support for A6 is |
| 1906 | configured - they may never become mainstream), then AAAA records are sought, |
| 1907 | and finally A records are sought as well. |
| 1908 | |
| 1909 | The host name may be changed if the DNS returns a different name - e.g. fully |
| 1910 | qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup |
| 1911 | ensures that it points to the fully qualified name. However, this is the fully |
| 1912 | qualified version of the original name; if a CNAME is involved, the actual |
| 1913 | canonical host name may be different again, and so we get it directly from the |
| 1914 | relevant RR. Note that we do NOT change the mx field of the host item in this |
| 1915 | function as it may be called to set the addresses of hosts taken from MX |
| 1916 | records. |
| 1917 | |
| 1918 | Arguments: |
| 1919 | host points to the host item we're filling in |
| 1920 | lastptr points to pointer to last host item in a chain of |
| 1921 | host items (may be updated if host is last and gets |
| 1922 | extended because multihomed) |
| 1923 | ignore_target_hosts list of hosts to ignore |
| 1924 | allow_ip if TRUE, recognize an IP address and return it |
| 1925 | fully_qualified_name if not NULL, return fully qualified name here if |
| 1926 | the contents are different (i.e. it must be preset |
| 1927 | to something) |
| 1928 | |
| 1929 | Returns: HOST_FIND_FAILED couldn't find A record |
| 1930 | HOST_FIND_AGAIN try again later |
| 1931 | HOST_FOUND found AAAA and/or A record(s) |
| 1932 | HOST_IGNORED found, but all IPs ignored |
| 1933 | */ |
| 1934 | |
| 1935 | static int |
| 1936 | set_address_from_dns(host_item *host, host_item **lastptr, |
| 1937 | uschar *ignore_target_hosts, BOOL allow_ip, uschar **fully_qualified_name) |
| 1938 | { |
| 1939 | dns_record *rr; |
| 1940 | host_item *thishostlast = NULL; /* Indicates not yet filled in anything */ |
| 1941 | BOOL v6_find_again = FALSE; |
| 1942 | int i; |
| 1943 | |
| 1944 | /* If allow_ip is set, a name which is an IP address returns that value |
| 1945 | as its address. This is used for MX records when allow_mx_to_ip is set, for |
| 1946 | those sites that feel they have to flaunt the RFC rules. */ |
| 1947 | |
| 1948 | if (allow_ip && string_is_ip_address(host->name, NULL) != 0) |
| 1949 | { |
| 1950 | #ifndef STAND_ALONE |
| 1951 | if (ignore_target_hosts != NULL && |
| 1952 | verify_check_this_host(&ignore_target_hosts, NULL, host->name, |
| 1953 | host->name, NULL) == OK) |
| 1954 | return HOST_IGNORED; |
| 1955 | #endif |
| 1956 | |
| 1957 | host->address = host->name; |
| 1958 | host->port = PORT_NONE; |
| 1959 | return HOST_FOUND; |
| 1960 | } |
| 1961 | |
| 1962 | /* On an IPv6 system, go round the loop up to three times, looking for A6 and |
| 1963 | AAAA records the first two times. However, unless doing standalone testing, we |
| 1964 | force an IPv4 lookup if the domain matches dns_ipv4_lookup is set. Since A6 |
| 1965 | records look like being abandoned, support them only if explicitly configured |
| 1966 | to do so. On an IPv4 system, go round the loop once only, looking only for A |
| 1967 | records. */ |
| 1968 | |
| 1969 | #if HAVE_IPV6 |
| 1970 | |
| 1971 | #ifndef STAND_ALONE |
| 1972 | if (dns_ipv4_lookup != NULL && |
| 1973 | match_isinlist(host->name, &dns_ipv4_lookup, 0, NULL, NULL, MCL_DOMAIN, |
| 1974 | TRUE, NULL) == OK) |
| 1975 | i = 0; /* look up A records only */ |
| 1976 | else |
| 1977 | #endif /* STAND_ALONE */ |
| 1978 | |
| 1979 | #ifdef SUPPORT_A6 |
| 1980 | i = 2; /* look up A6 and AAAA and A records */ |
| 1981 | #else |
| 1982 | i = 1; /* look up AAAA and A records */ |
| 1983 | #endif /* SUPPORT_A6 */ |
| 1984 | |
| 1985 | /* The IPv4 world */ |
| 1986 | |
| 1987 | #else /* HAVE_IPV6 */ |
| 1988 | i = 0; /* look up A records only */ |
| 1989 | #endif /* HAVE_IPV6 */ |
| 1990 | |
| 1991 | for (; i >= 0; i--) |
| 1992 | { |
| 1993 | static int types[] = { T_A, T_AAAA, T_A6 }; |
| 1994 | int type = types[i]; |
| 1995 | int randoffset = (i == 0)? 500 : 0; /* Ensures v6 sorts before v4 */ |
| 1996 | dns_answer dnsa; |
| 1997 | dns_scan dnss; |
| 1998 | |
| 1999 | int rc = dns_lookup(&dnsa, host->name, type, fully_qualified_name); |
| 2000 | |
| 2001 | /* We want to return HOST_FIND_AGAIN if one of the A, A6, or AAAA lookups |
| 2002 | fails or times out, but not if another one succeeds. (In the early |
| 2003 | IPv6 days there are name servers that always fail on AAAA, but are happy |
| 2004 | to give out an A record. We want to proceed with that A record.) */ |
| 2005 | |
| 2006 | if (rc != DNS_SUCCEED) |
| 2007 | { |
| 2008 | if (i == 0) /* Just tried for an A record, i.e. end of loop */ |
| 2009 | { |
| 2010 | if (host->address != NULL) return HOST_FOUND; /* A6 or AAAA was found */ |
| 2011 | if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again) |
| 2012 | return HOST_FIND_AGAIN; |
| 2013 | return HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */ |
| 2014 | } |
| 2015 | |
| 2016 | /* Tried for an A6 or AAAA record: remember if this was a temporary |
| 2017 | error, and look for the next record type. */ |
| 2018 | |
| 2019 | if (rc != DNS_NOMATCH && rc != DNS_NODATA) v6_find_again = TRUE; |
| 2020 | continue; |
| 2021 | } |
| 2022 | |
| 2023 | /* Lookup succeeded: fill in the given host item with the first non-ignored |
| 2024 | address found; create additional items for any others. A single A6 record |
| 2025 | may generate more than one address. */ |
| 2026 | |
| 2027 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
| 2028 | rr != NULL; |
| 2029 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) |
| 2030 | { |
| 2031 | if (rr->type == type) |
| 2032 | { |
| 2033 | /* dns_address *da = dns_address_from_rr(&dnsa, rr); */ |
| 2034 | |
| 2035 | dns_address *da; |
| 2036 | da = dns_address_from_rr(&dnsa, rr); |
| 2037 | |
| 2038 | DEBUG(D_host_lookup) |
| 2039 | { |
| 2040 | if (da == NULL) |
| 2041 | debug_printf("no addresses extracted from A6 RR for %s\n", |
| 2042 | host->name); |
| 2043 | } |
| 2044 | |
| 2045 | /* This loop runs only once for A and AAAA records, but may run |
| 2046 | several times for an A6 record that generated multiple addresses. */ |
| 2047 | |
| 2048 | for (; da != NULL; da = da->next) |
| 2049 | { |
| 2050 | #ifndef STAND_ALONE |
| 2051 | if (ignore_target_hosts != NULL && |
| 2052 | verify_check_this_host(&ignore_target_hosts, NULL, |
| 2053 | host->name, da->address, NULL) == OK) |
| 2054 | { |
| 2055 | DEBUG(D_host_lookup) |
| 2056 | debug_printf("ignored host %s [%s]\n", host->name, da->address); |
| 2057 | continue; |
| 2058 | } |
| 2059 | #endif |
| 2060 | |
| 2061 | /* If this is the first address, stick it in the given host block, |
| 2062 | and change the name if the returned RR has a different name. */ |
| 2063 | |
| 2064 | if (thishostlast == NULL) |
| 2065 | { |
| 2066 | if (strcmpic(host->name, rr->name) != 0) |
| 2067 | host->name = string_copy_dnsdomain(rr->name); |
| 2068 | host->address = da->address; |
| 2069 | host->port = PORT_NONE; |
| 2070 | host->sort_key = host->mx * 1000 + random_number(500) + randoffset; |
| 2071 | host->status = hstatus_unknown; |
| 2072 | host->why = hwhy_unknown; |
| 2073 | thishostlast = host; |
| 2074 | } |
| 2075 | |
| 2076 | /* Not the first address. Check for, and ignore, duplicates. Then |
| 2077 | insert in the chain at a random point. */ |
| 2078 | |
| 2079 | else |
| 2080 | { |
| 2081 | int new_sort_key; |
| 2082 | host_item *next; |
| 2083 | |
| 2084 | /* End of our local chain is specified by "thishostlast". */ |
| 2085 | |
| 2086 | for (next = host;; next = next->next) |
| 2087 | { |
| 2088 | if (Ustrcmp(CS da->address, next->address) == 0) break; |
| 2089 | if (next == thishostlast) { next = NULL; break; } |
| 2090 | } |
| 2091 | if (next != NULL) continue; /* With loop for next address */ |
| 2092 | |
| 2093 | /* Not a duplicate */ |
| 2094 | |
| 2095 | new_sort_key = host->mx * 1000 + random_number(500) + randoffset; |
| 2096 | next = store_get(sizeof(host_item)); |
| 2097 | |
| 2098 | /* New address goes first: insert the new block after the first one |
| 2099 | (so as not to disturb the original pointer) but put the new address |
| 2100 | in the original block. */ |
| 2101 | |
| 2102 | if (new_sort_key < host->sort_key) |
| 2103 | { |
| 2104 | *next = *host; |
| 2105 | host->next = next; |
| 2106 | host->address = da->address; |
| 2107 | host->port = PORT_NONE; |
| 2108 | host->sort_key = new_sort_key; |
| 2109 | if (thishostlast == host) thishostlast = next; /* Local last */ |
| 2110 | if (*lastptr == host) *lastptr = next; /* Global last */ |
| 2111 | } |
| 2112 | |
| 2113 | /* Otherwise scan down the addresses for this host to find the |
| 2114 | one to insert after. */ |
| 2115 | |
| 2116 | else |
| 2117 | { |
| 2118 | host_item *h = host; |
| 2119 | while (h != thishostlast) |
| 2120 | { |
| 2121 | if (new_sort_key < h->next->sort_key) break; |
| 2122 | h = h->next; |
| 2123 | } |
| 2124 | *next = *h; |
| 2125 | h->next = next; |
| 2126 | next->address = da->address; |
| 2127 | next->port = PORT_NONE; |
| 2128 | next->sort_key = new_sort_key; |
| 2129 | if (h == thishostlast) thishostlast = next; /* Local last */ |
| 2130 | if (h == *lastptr) *lastptr = next; /* Global last */ |
| 2131 | } |
| 2132 | } |
| 2133 | } |
| 2134 | } |
| 2135 | } |
| 2136 | } |
| 2137 | |
| 2138 | /* Control gets here only if the third lookup (the A record) succeeded. |
| 2139 | However, the address may not be filled in if it was ignored. */ |
| 2140 | |
| 2141 | return (host->address == NULL)? HOST_IGNORED : HOST_FOUND; |
| 2142 | } |
| 2143 | |
| 2144 | |
| 2145 | |
| 2146 | |
| 2147 | /************************************************* |
| 2148 | * Find IP addresses and names for host via DNS * |
| 2149 | *************************************************/ |
| 2150 | |
| 2151 | /* The input is a host_item structure with the name filled in and the address |
| 2152 | field set to NULL. This may be in a chain of other host items. The lookup may |
| 2153 | result in more than one IP address, in which case we must created new host |
| 2154 | blocks for the additional addresses, and insert them into the chain. The |
| 2155 | original name may not be fully qualified. Use the fully_qualified_name argument |
| 2156 | to return the official name, as returned by the resolver. |
| 2157 | |
| 2158 | Arguments: |
| 2159 | host point to initial host item |
| 2160 | ignore_target_hosts a list of hosts to ignore |
| 2161 | whichrrs flags indicating which RRs to look for: |
| 2162 | HOST_FIND_BY_SRV => look for SRV |
| 2163 | HOST_FIND_BY_MX => look for MX |
| 2164 | HOST_FIND_BY_A => look for A or AAAA |
| 2165 | also flags indicating how the lookup is done |
| 2166 | HOST_FIND_QUALIFY_SINGLE ) passed to the |
| 2167 | HOST_FIND_SEARCH_PARENTS ) resolver |
| 2168 | srv_service when SRV used, the service name |
| 2169 | srv_fail_domains DNS errors for these domains => assume nonexist |
| 2170 | mx_fail_domains DNS errors for these domains => assume nonexist |
| 2171 | fully_qualified_name if not NULL, return fully-qualified name |
| 2172 | removed set TRUE if local host was removed from the list |
| 2173 | |
| 2174 | Returns: HOST_FIND_FAILED Failed to find the host or domain; |
| 2175 | if there was a syntax error, |
| 2176 | host_find_failed_syntax is set. |
| 2177 | HOST_FIND_AGAIN Could not resolve at this time |
| 2178 | HOST_FOUND Host found |
| 2179 | HOST_FOUND_LOCAL The lowest MX record points to this |
| 2180 | machine, if MX records were found, or |
| 2181 | an A record that was found contains |
| 2182 | an address of the local host |
| 2183 | */ |
| 2184 | |
| 2185 | int |
| 2186 | host_find_bydns(host_item *host, uschar *ignore_target_hosts, int whichrrs, |
| 2187 | uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains, |
| 2188 | uschar **fully_qualified_name, BOOL *removed) |
| 2189 | { |
| 2190 | host_item *h, *last; |
| 2191 | dns_record *rr; |
| 2192 | int rc = DNS_FAIL; |
| 2193 | int ind_type = 0; |
| 2194 | int yield; |
| 2195 | dns_answer dnsa; |
| 2196 | dns_scan dnss; |
| 2197 | |
| 2198 | /* Set the default fully qualified name to the incoming name, initialize the |
| 2199 | resolver if necessary, set up the relevant options, and initialize the flag |
| 2200 | that gets set for DNS syntax check errors. */ |
| 2201 | |
| 2202 | if (fully_qualified_name != NULL) *fully_qualified_name = host->name; |
| 2203 | dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0, |
| 2204 | (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0); |
| 2205 | host_find_failed_syntax = FALSE; |
| 2206 | |
| 2207 | /* First, if requested, look for SRV records. The service name is given; we |
| 2208 | assume TCP progocol. DNS domain names are constrained to a maximum of 256 |
| 2209 | characters, so the code below should be safe. */ |
| 2210 | |
| 2211 | if ((whichrrs & HOST_FIND_BY_SRV) != 0) |
| 2212 | { |
| 2213 | uschar buffer[300]; |
| 2214 | uschar *temp_fully_qualified_name = buffer; |
| 2215 | int prefix_length; |
| 2216 | |
| 2217 | (void)sprintf(CS buffer, "_%s._tcp.%n%.256s", srv_service, &prefix_length, |
| 2218 | host->name); |
| 2219 | ind_type = T_SRV; |
| 2220 | |
| 2221 | /* Search for SRV records. If the fully qualified name is different to |
| 2222 | the input name, pass back the new original domain, without the prepended |
| 2223 | magic. */ |
| 2224 | |
| 2225 | rc = dns_lookup(&dnsa, buffer, ind_type, &temp_fully_qualified_name); |
| 2226 | if (temp_fully_qualified_name != buffer && fully_qualified_name != NULL) |
| 2227 | *fully_qualified_name = temp_fully_qualified_name + prefix_length; |
| 2228 | |
| 2229 | /* On DNS failures, we give the "try again" error unless the domain is |
| 2230 | listed as one for which we continue. */ |
| 2231 | |
| 2232 | if (rc == DNS_FAIL || rc == DNS_AGAIN) |
| 2233 | { |
| 2234 | if (match_isinlist(host->name, &srv_fail_domains, 0, NULL, NULL, MCL_DOMAIN, |
| 2235 | TRUE, NULL) != OK) |
| 2236 | return HOST_FIND_AGAIN; |
| 2237 | DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA " |
| 2238 | "(domain in srv_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN"); |
| 2239 | } |
| 2240 | } |
| 2241 | |
| 2242 | /* If we did not find any SRV records, search the DNS for MX records, if |
| 2243 | requested to do so. If the result is DNS_NOMATCH, it means there is no such |
| 2244 | domain, and there's no point in going on to look for address records with the |
| 2245 | same domain. The result will be DNS_NODATA if the domain exists but has no MX |
| 2246 | records. On DNS failures, we give the "try again" error unless the domain is |
| 2247 | listed as one for which we continue. */ |
| 2248 | |
| 2249 | if (rc != DNS_SUCCEED && (whichrrs & HOST_FIND_BY_MX) != 0) |
| 2250 | { |
| 2251 | ind_type = T_MX; |
| 2252 | rc = dns_lookup(&dnsa, host->name, ind_type, fully_qualified_name); |
| 2253 | if (rc == DNS_NOMATCH) return HOST_FIND_FAILED; |
| 2254 | if (rc == DNS_FAIL || rc == DNS_AGAIN) |
| 2255 | { |
| 2256 | if (match_isinlist(host->name, &mx_fail_domains, 0, NULL, NULL, MCL_DOMAIN, |
| 2257 | TRUE, NULL) != OK) |
| 2258 | return HOST_FIND_AGAIN; |
| 2259 | DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA " |
| 2260 | "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN"); |
| 2261 | } |
| 2262 | } |
| 2263 | |
| 2264 | /* If we haven't found anything yet, and we are requested to do so, try for an |
| 2265 | A or AAAA record. If we find it (or them) check to see that it isn't the local |
| 2266 | host. */ |
| 2267 | |
| 2268 | if (rc != DNS_SUCCEED) |
| 2269 | { |
| 2270 | if ((whichrrs & HOST_FIND_BY_A) == 0) |
| 2271 | { |
| 2272 | DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n"); |
| 2273 | return HOST_FIND_FAILED; |
| 2274 | } |
| 2275 | |
| 2276 | last = host; /* End of local chainlet */ |
| 2277 | host->mx = MX_NONE; |
| 2278 | host->port = PORT_NONE; |
| 2279 | rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE, |
| 2280 | fully_qualified_name); |
| 2281 | |
| 2282 | /* If one or more address records have been found, check that none of them |
| 2283 | are local. Since we know the host items all have their IP addresses |
| 2284 | inserted, host_scan_for_local_hosts() can only return HOST_FOUND or |
| 2285 | HOST_FOUND_LOCAL. We do not need to scan for duplicate IP addresses here, |
| 2286 | because set_address_from_dns() removes them. */ |
| 2287 | |
| 2288 | if (rc == HOST_FOUND) |
| 2289 | rc = host_scan_for_local_hosts(host, &last, removed); |
| 2290 | else |
| 2291 | if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */ |
| 2292 | |
| 2293 | /* When running in the test harness, sort into the order of addresses so as |
| 2294 | to get repeatability. */ |
| 2295 | |
| 2296 | if (running_in_test_harness) sort_addresses(host, last); |
| 2297 | |
| 2298 | DEBUG(D_host_lookup) |
| 2299 | { |
| 2300 | host_item *h; |
| 2301 | if (host->address != NULL) |
| 2302 | { |
| 2303 | if (fully_qualified_name != NULL) |
| 2304 | debug_printf("fully qualified name = %s\n", *fully_qualified_name); |
| 2305 | for (h = host; h != last->next; h = h->next) |
| 2306 | debug_printf("%s %s mx=%d sort=%d %s\n", h->name, |
| 2307 | (h->address == NULL)? US"<null>" : h->address, h->mx, h->sort_key, |
| 2308 | (h->status >= hstatus_unusable)? US"*" : US""); |
| 2309 | } |
| 2310 | } |
| 2311 | |
| 2312 | return rc; |
| 2313 | } |
| 2314 | |
| 2315 | /* We have found one or more MX or SRV records. Sort them according to |
| 2316 | precedence. Put the data for the first one into the existing host block, and |
| 2317 | insert new host_item blocks into the chain for the remainder. For equal |
| 2318 | precedences one is supposed to randomize the order. To make this happen, the |
| 2319 | sorting is actually done on the MX value * 1000 + a random number. This is put |
| 2320 | into a host field called sort_key. |
| 2321 | |
| 2322 | In the case of hosts with both IPv6 and IPv4 addresses, we want to choose the |
| 2323 | IPv6 address in preference. At this stage, we don't know what kind of address |
| 2324 | the host has. We choose a random number < 500; if later we find an A record |
| 2325 | first, we add 500 to the random number. Then for any other address records, we |
| 2326 | use random numbers in the range 0-499 for AAAA records and 500-999 for A |
| 2327 | records. |
| 2328 | |
| 2329 | At this point we remove any duplicates that point to the same host, retaining |
| 2330 | only the one with the lowest precedence. We cannot yet check for precedence |
| 2331 | greater than that of the local host, because that test cannot be properly done |
| 2332 | until the addresses have been found - an MX record may point to a name for this |
| 2333 | host which is not the primary hostname. */ |
| 2334 | |
| 2335 | last = NULL; /* Indicates that not even the first item is filled yet */ |
| 2336 | |
| 2337 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); |
| 2338 | rr != NULL; |
| 2339 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) |
| 2340 | { |
| 2341 | int precedence; |
| 2342 | int weight = 0; /* For SRV records */ |
| 2343 | int port = PORT_NONE; /* For SRV records */ |
| 2344 | uschar *s; /* MUST be unsigned for GETSHORT */ |
| 2345 | uschar data[256]; |
| 2346 | |
| 2347 | if (rr->type != ind_type) continue; |
| 2348 | s = rr->data; |
| 2349 | GETSHORT(precedence, s); /* Pointer s is advanced */ |
| 2350 | |
| 2351 | /* For MX records, we use a random "weight" which causes multiple records of |
| 2352 | the same precedence to sort randomly. */ |
| 2353 | |
| 2354 | if (ind_type == T_MX) |
| 2355 | { |
| 2356 | weight = random_number(500); |
| 2357 | } |
| 2358 | |
| 2359 | /* SRV records are specified with a port and a weight. The weight is used |
| 2360 | in a special algorithm. However, to start with, we just use it to order the |
| 2361 | records of equal priority (precedence). */ |
| 2362 | |
| 2363 | else |
| 2364 | { |
| 2365 | GETSHORT(weight, s); |
| 2366 | GETSHORT(port, s); |
| 2367 | } |
| 2368 | |
| 2369 | /* Get the name of the host pointed to. */ |
| 2370 | |
| 2371 | (void)dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, s, |
| 2372 | (DN_EXPAND_ARG4_TYPE)data, sizeof(data)); |
| 2373 | |
| 2374 | /* Check that we haven't already got this host on the chain; if we have, |
| 2375 | keep only the lower precedence. This situation shouldn't occur, but you |
| 2376 | never know what junk might get into the DNS (and this case has been seen on |
| 2377 | more than one occasion). */ |
| 2378 | |
| 2379 | if (last != NULL) /* This is not the first record */ |
| 2380 | { |
| 2381 | host_item *prev = NULL; |
| 2382 | |
| 2383 | for (h = host; h != last->next; prev = h, h = h->next) |
| 2384 | { |
| 2385 | if (strcmpic(h->name, data) == 0) |
| 2386 | { |
| 2387 | DEBUG(D_host_lookup) |
| 2388 | debug_printf("discarded duplicate host %s (MX=%d)\n", data, |
| 2389 | (precedence > h->mx)? precedence : h->mx); |
| 2390 | if (precedence >= h->mx) goto NEXT_MX_RR; /* Skip greater precedence */ |
| 2391 | if (h == host) /* Override first item */ |
| 2392 | { |
| 2393 | h->mx = precedence; |
| 2394 | host->sort_key = precedence * 1000 + weight; |
| 2395 | goto NEXT_MX_RR; |
| 2396 | } |
| 2397 | |
| 2398 | /* Unwanted host item is not the first in the chain, so we can get |
| 2399 | get rid of it by cutting it out. */ |
| 2400 | |
| 2401 | prev->next = h->next; |
| 2402 | if (h == last) last = prev; |
| 2403 | break; |
| 2404 | } |
| 2405 | } |
| 2406 | } |
| 2407 | |
| 2408 | /* If this is the first MX or SRV record, put the data into the existing host |
| 2409 | block. Otherwise, add a new block in the correct place; if it has to be |
| 2410 | before the first block, copy the first block's data to a new second block. */ |
| 2411 | |
| 2412 | if (last == NULL) |
| 2413 | { |
| 2414 | host->name = string_copy_dnsdomain(data); |
| 2415 | host->address = NULL; |
| 2416 | host->port = port; |
| 2417 | host->mx = precedence; |
| 2418 | host->sort_key = precedence * 1000 + weight; |
| 2419 | host->status = hstatus_unknown; |
| 2420 | host->why = hwhy_unknown; |
| 2421 | last = host; |
| 2422 | } |
| 2423 | |
| 2424 | /* Make a new host item and seek the correct insertion place */ |
| 2425 | |
| 2426 | else |
| 2427 | { |
| 2428 | int sort_key = precedence * 1000 + weight; |
| 2429 | host_item *next = store_get(sizeof(host_item)); |
| 2430 | next->name = string_copy_dnsdomain(data); |
| 2431 | next->address = NULL; |
| 2432 | next->port = port; |
| 2433 | next->mx = precedence; |
| 2434 | next->sort_key = sort_key; |
| 2435 | next->status = hstatus_unknown; |
| 2436 | next->why = hwhy_unknown; |
| 2437 | next->last_try = 0; |
| 2438 | |
| 2439 | /* Handle the case when we have to insert before the first item. */ |
| 2440 | |
| 2441 | if (sort_key < host->sort_key) |
| 2442 | { |
| 2443 | host_item htemp; |
| 2444 | htemp = *host; |
| 2445 | *host = *next; |
| 2446 | *next = htemp; |
| 2447 | host->next = next; |
| 2448 | if (last == host) last = next; |
| 2449 | } |
| 2450 | |
| 2451 | /* Else scan down the items we have inserted as part of this exercise; |
| 2452 | don't go further. */ |
| 2453 | |
| 2454 | else |
| 2455 | { |
| 2456 | for (h = host; h != last; h = h->next) |
| 2457 | { |
| 2458 | if (sort_key < h->next->sort_key) |
| 2459 | { |
| 2460 | next->next = h->next; |
| 2461 | h->next = next; |
| 2462 | break; |
| 2463 | } |
| 2464 | } |
| 2465 | |
| 2466 | /* Join on after the last host item that's part of this |
| 2467 | processing if we haven't stopped sooner. */ |
| 2468 | |
| 2469 | if (h == last) |
| 2470 | { |
| 2471 | next->next = last->next; |
| 2472 | last->next = next; |
| 2473 | last = next; |
| 2474 | } |
| 2475 | } |
| 2476 | } |
| 2477 | |
| 2478 | NEXT_MX_RR: continue; |
| 2479 | } |
| 2480 | |
| 2481 | /* If the list of hosts was obtained from SRV records, there are two things to |
| 2482 | do. First, if there is only one host, and it's name is ".", it means there is |
| 2483 | no SMTP service at this domain. Otherwise, we have to sort the hosts of equal |
| 2484 | priority according to their weights, using an algorithm that is defined in RFC |
| 2485 | 2782. The hosts are currently sorted by priority and weight. For each priority |
| 2486 | group we have to pick off one host and put it first, and then repeat for any |
| 2487 | remaining in the same priority group. */ |
| 2488 | |
| 2489 | if (ind_type == T_SRV) |
| 2490 | { |
| 2491 | host_item **pptr; |
| 2492 | |
| 2493 | if (host == last && host->name[0] == 0) |
| 2494 | { |
| 2495 | DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n"); |
| 2496 | return HOST_FIND_FAILED; |
| 2497 | } |
| 2498 | |
| 2499 | DEBUG(D_host_lookup) |
| 2500 | { |
| 2501 | debug_printf("original ordering of hosts from SRV records:\n"); |
| 2502 | for (h = host; h != last->next; h = h->next) |
| 2503 | debug_printf(" %s P=%d W=%d\n", h->name, h->mx, h->sort_key % 1000); |
| 2504 | } |
| 2505 | |
| 2506 | for (pptr = &host, h = host; h != last; pptr = &(h->next), h = h->next) |
| 2507 | { |
| 2508 | int sum = 0; |
| 2509 | host_item *hh; |
| 2510 | |
| 2511 | /* Find the last following host that has the same precedence. At the same |
| 2512 | time, compute the sum of the weights and the running totals. These can be |
| 2513 | stored in the sort_key field. */ |
| 2514 | |
| 2515 | for (hh = h; hh != last; hh = hh->next) |
| 2516 | { |
| 2517 | int weight = hh->sort_key % 1000; /* was precedence * 1000 + weight */ |
| 2518 | sum += weight; |
| 2519 | hh->sort_key = sum; |
| 2520 | if (hh->mx != hh->next->mx) break; |
| 2521 | } |
| 2522 | |
| 2523 | /* If there's more than one host at this precedence (priority), we need to |
| 2524 | pick one to go first. */ |
| 2525 | |
| 2526 | if (hh != h) |
| 2527 | { |
| 2528 | host_item *hhh; |
| 2529 | host_item **ppptr; |
| 2530 | int randomizer = random_number(sum + 1); |
| 2531 | |
| 2532 | for (ppptr = pptr, hhh = h; |
| 2533 | hhh != hh; |
| 2534 | ppptr = &(hhh->next), hhh = hhh->next) |
| 2535 | { |
| 2536 | if (hhh->sort_key >= randomizer) break; |
| 2537 | } |
| 2538 | |
| 2539 | /* hhh now points to the host that should go first; ppptr points to the |
| 2540 | place that points to it. Unfortunately, if the start of the minilist is |
| 2541 | the start of the entire list, we can't just swap the items over, because |
| 2542 | we must not change the value of host, since it is passed in from outside. |
| 2543 | One day, this could perhaps be changed. |
| 2544 | |
| 2545 | The special case is fudged by putting the new item *second* in the chain, |
| 2546 | and then transferring the data between the first and second items. We |
| 2547 | can't just swap the first and the chosen item, because that would mean |
| 2548 | that an item with zero weight might no longer be first. */ |
| 2549 | |
| 2550 | if (hhh != h) |
| 2551 | { |
| 2552 | *ppptr = hhh->next; /* Cuts it out of the chain */ |
| 2553 | |
| 2554 | if (h == host) |
| 2555 | { |
| 2556 | host_item temp = *h; |
| 2557 | *h = *hhh; |
| 2558 | *hhh = temp; |
| 2559 | hhh->next = temp.next; |
| 2560 | h->next = hhh; |
| 2561 | } |
| 2562 | |
| 2563 | else |
| 2564 | { |
| 2565 | hhh->next = h; /* The rest of the chain follows it */ |
| 2566 | *pptr = hhh; /* It takes the place of h */ |
| 2567 | h = hhh; /* It's now the start of this minilist */ |
| 2568 | } |
| 2569 | } |
| 2570 | } |
| 2571 | |
| 2572 | /* A host has been chosen to be first at this priority and h now points |
| 2573 | to this host. There may be others at the same priority, or others at a |
| 2574 | different priority. Before we leave this host, we need to put back a sort |
| 2575 | key of the traditional MX kind, in case this host is multihomed, because |
| 2576 | the sort key is used for ordering the multiple IP addresses. We do not need |
| 2577 | to ensure that these new sort keys actually reflect the order of the hosts, |
| 2578 | however. */ |
| 2579 | |
| 2580 | h->sort_key = h->mx * 1000 + random_number(500); |
| 2581 | } /* Move on to the next host */ |
| 2582 | } |
| 2583 | |
| 2584 | /* Now we have to ensure addresses exist for all the hosts. We have ensured |
| 2585 | above that the names in the host items are all unique. The addresses may have |
| 2586 | been returned in the additional data section of the DNS query. Because it is |
| 2587 | more expensive to scan the returned DNS records (because you have to expand the |
| 2588 | names) we do a single scan over them, and multiple scans of the chain of host |
| 2589 | items (which is typically only 3 or 4 long anyway.) Add extra host items for |
| 2590 | multi-homed hosts. */ |
| 2591 | |
| 2592 | for (rr = dns_next_rr(&dnsa, &dnss, RESET_ADDITIONAL); |
| 2593 | rr != NULL; |
| 2594 | rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) |
| 2595 | { |
| 2596 | dns_address *da; |
| 2597 | int status = hstatus_unknown; |
| 2598 | int why = hwhy_unknown; |
| 2599 | int randoffset; |
| 2600 | |
| 2601 | if (rr->type != T_A |
| 2602 | #if HAVE_IPV6 |
| 2603 | && rr->type != T_AAAA |
| 2604 | #ifdef SUPPORT_A6 |
| 2605 | && rr->type != T_A6 |
| 2606 | #endif |
| 2607 | #endif |
| 2608 | ) continue; |
| 2609 | |
| 2610 | /* Find the first host that matches this record's name. If there isn't |
| 2611 | one, move on to the next RR. */ |
| 2612 | |
| 2613 | for (h = host; h != last->next; h = h->next) |
| 2614 | { if (strcmpic(h->name, rr->name) == 0) break; } |
| 2615 | if (h == last->next) continue; |
| 2616 | |
| 2617 | /* For IPv4 addresses, add 500 to the random part of the sort key, to ensure |
| 2618 | they sort after IPv6 addresses. */ |
| 2619 | |
| 2620 | randoffset = (rr->type == T_A)? 500 : 0; |
| 2621 | |
| 2622 | /* Get the list of textual addresses for this RR. There may be more than one |
| 2623 | if it is an A6 RR. Then loop to handle multiple addresses from an A6 record. |
| 2624 | If there are none, nothing will get done - the record is ignored. */ |
| 2625 | |
| 2626 | for (da = dns_address_from_rr(&dnsa, rr); da != NULL; da = da->next) |
| 2627 | { |
| 2628 | /* Set status for an ignorable host. */ |
| 2629 | |
| 2630 | #ifndef STAND_ALONE |
| 2631 | if (ignore_target_hosts != NULL && |
| 2632 | verify_check_this_host(&ignore_target_hosts, NULL, h->name, |
| 2633 | da->address, NULL) == OK) |
| 2634 | { |
| 2635 | DEBUG(D_host_lookup) |
| 2636 | debug_printf("ignored host %s [%s]\n", h->name, da->address); |
| 2637 | status = hstatus_unusable; |
| 2638 | why = hwhy_ignored; |
| 2639 | } |
| 2640 | #endif |
| 2641 | |
| 2642 | /* If the address is already set for this host, it may be that |
| 2643 | we just have a duplicate DNS record. Alternatively, this may be |
| 2644 | a multi-homed host. Search all items with the same host name |
| 2645 | (they will all be together) and if this address is found, skip |
| 2646 | to the next RR. */ |
| 2647 | |
| 2648 | if (h->address != NULL) |
| 2649 | { |
| 2650 | int new_sort_key; |
| 2651 | host_item *thishostlast; |
| 2652 | host_item *hh = h; |
| 2653 | |
| 2654 | do |
| 2655 | { |
| 2656 | if (hh->address != NULL && Ustrcmp(CS da->address, hh->address) == 0) |
| 2657 | goto DNS_NEXT_RR; /* Need goto to escape from inner loop */ |
| 2658 | thishostlast = hh; |
| 2659 | hh = hh->next; |
| 2660 | } |
| 2661 | while (hh != last->next && strcmpic(hh->name, rr->name) == 0); |
| 2662 | |
| 2663 | /* We have a multi-homed host, since we have a new address for |
| 2664 | an existing name. Create a copy of the current item, and give it |
| 2665 | the new address. RRs can be in arbitrary order, but one is supposed |
| 2666 | to randomize the addresses of multi-homed hosts, so compute a new |
| 2667 | sorting key and do that. [Latest SMTP RFC says not to randomize multi- |
| 2668 | homed hosts, but to rely on the resolver. I'm not happy about that - |
| 2669 | caching in the resolver will not rotate as often as the name server |
| 2670 | does.] */ |
| 2671 | |
| 2672 | new_sort_key = h->mx * 1000 + random_number(500) + randoffset; |
| 2673 | hh = store_get(sizeof(host_item)); |
| 2674 | |
| 2675 | /* New address goes first: insert the new block after the first one |
| 2676 | (so as not to disturb the original pointer) but put the new address |
| 2677 | in the original block. */ |
| 2678 | |
| 2679 | if (new_sort_key < h->sort_key) |
| 2680 | { |
| 2681 | *hh = *h; /* Note: copies the port */ |
| 2682 | h->next = hh; |
| 2683 | h->address = da->address; |
| 2684 | h->sort_key = new_sort_key; |
| 2685 | h->status = status; |
| 2686 | h->why = why; |
| 2687 | } |
| 2688 | |
| 2689 | /* Otherwise scan down the addresses for this host to find the |
| 2690 | one to insert after. */ |
| 2691 | |
| 2692 | else |
| 2693 | { |
| 2694 | while (h != thishostlast) |
| 2695 | { |
| 2696 | if (new_sort_key < h->next->sort_key) break; |
| 2697 | h = h->next; |
| 2698 | } |
| 2699 | *hh = *h; /* Note: copies the port */ |
| 2700 | h->next = hh; |
| 2701 | hh->address = da->address; |
| 2702 | hh->sort_key = new_sort_key; |
| 2703 | hh->status = status; |
| 2704 | hh->why = why; |
| 2705 | } |
| 2706 | |
| 2707 | if (h == last) last = hh; /* Inserted after last */ |
| 2708 | } |
| 2709 | |
| 2710 | /* The existing item doesn't have its address set yet, so just set it. |
| 2711 | Ensure that an IPv4 address gets its sort key incremented in case an IPv6 |
| 2712 | address is found later. */ |
| 2713 | |
| 2714 | else |
| 2715 | { |
| 2716 | h->address = da->address; /* Port should be set already */ |
| 2717 | h->status = status; |
| 2718 | h->why = why; |
| 2719 | h->sort_key += randoffset; |
| 2720 | } |
| 2721 | } /* Loop for addresses extracted from one RR */ |
| 2722 | |
| 2723 | /* Carry on to the next RR. It would be nice to be able to be able to stop |
| 2724 | when every host on the list has an address, but we can't be sure there won't |
| 2725 | be an additional address for a multi-homed host further down the list, so |
| 2726 | we have to continue to the end. */ |
| 2727 | |
| 2728 | DNS_NEXT_RR: continue; |
| 2729 | } |
| 2730 | |
| 2731 | /* Set the default yield to failure */ |
| 2732 | |
| 2733 | yield = HOST_FIND_FAILED; |
| 2734 | |
| 2735 | /* If we haven't found all the addresses in the additional section, we |
| 2736 | need to search for A or AAAA records explicitly. The names shouldn't point to |
| 2737 | CNAMES, but we use the general lookup function that handles them, just |
| 2738 | in case. If any lookup gives a soft error, change the default yield. |
| 2739 | |
| 2740 | For these DNS lookups, we must disable qualify_single and search_parents; |
| 2741 | otherwise invalid host names obtained from MX or SRV records can cause trouble |
| 2742 | if they happen to match something local. */ |
| 2743 | |
| 2744 | dns_init(FALSE, FALSE); |
| 2745 | |
| 2746 | for (h = host; h != last->next; h = h->next) |
| 2747 | { |
| 2748 | if (h->address != NULL || h->status == hstatus_unusable) continue; |
| 2749 | rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip, NULL); |
| 2750 | if (rc != HOST_FOUND) |
| 2751 | { |
| 2752 | h->status = hstatus_unusable; |
| 2753 | if (rc == HOST_FIND_AGAIN) |
| 2754 | { |
| 2755 | yield = rc; |
| 2756 | h->why = hwhy_deferred; |
| 2757 | } |
| 2758 | else |
| 2759 | h->why = (rc == HOST_IGNORED)? hwhy_ignored : hwhy_failed; |
| 2760 | } |
| 2761 | } |
| 2762 | |
| 2763 | /* Scan the list for any hosts that are marked unusable because they have |
| 2764 | been explicitly ignored, and remove them from the list, as if they did not |
| 2765 | exist. If we end up with just a single, ignored host, flatten its fields as if |
| 2766 | nothing was found. */ |
| 2767 | |
| 2768 | if (ignore_target_hosts != NULL) |
| 2769 | { |
| 2770 | host_item *prev = NULL; |
| 2771 | for (h = host; h != last->next; h = h->next) |
| 2772 | { |
| 2773 | REDO: |
| 2774 | if (h->why != hwhy_ignored) /* Non ignored host, just continue */ |
| 2775 | prev = h; |
| 2776 | else if (prev == NULL) /* First host is ignored */ |
| 2777 | { |
| 2778 | if (h != last) /* First is not last */ |
| 2779 | { |
| 2780 | if (h->next == last) last = h; /* Overwrite it with next */ |
| 2781 | *h = *(h->next); /* and reprocess it. */ |
| 2782 | goto REDO; /* C should have redo, like Perl */ |
| 2783 | } |
| 2784 | } |
| 2785 | else /* Ignored host is not first - */ |
| 2786 | { /* cut it out */ |
| 2787 | prev->next = h->next; |
| 2788 | if (h == last) last = prev; |
| 2789 | } |
| 2790 | } |
| 2791 | |
| 2792 | if (host->why == hwhy_ignored) host->address = NULL; |
| 2793 | } |
| 2794 | |
| 2795 | /* There is still one complication in the case of IPv6. Although the code above |
| 2796 | arranges that IPv6 addresses take precedence over IPv4 addresses for multihomed |
| 2797 | hosts, it doesn't do this for addresses that apply to different hosts with the |
| 2798 | same MX precedence, because the sorting on MX precedence happens first. So we |
| 2799 | have to make another pass to check for this case. We ensure that, within a |
| 2800 | single MX preference value, IPv6 addresses come first. This can separate the |
| 2801 | addresses of a multihomed host, but that should not matter. */ |
| 2802 | |
| 2803 | #if HAVE_IPV6 |
| 2804 | if (h != last) |
| 2805 | { |
| 2806 | for (h = host; h != last; h = h->next) |
| 2807 | { |
| 2808 | host_item temp; |
| 2809 | host_item *next = h->next; |
| 2810 | if (h->mx != next->mx || /* If next is different MX value */ |
| 2811 | (h->sort_key % 1000) < 500 || /* OR this one is IPv6 */ |
| 2812 | (next->sort_key % 1000) >= 500) /* OR next is IPv4 */ |
| 2813 | continue; /* move on to next */ |
| 2814 | temp = *h; |
| 2815 | temp.next = next->next; |
| 2816 | *h = *next; |
| 2817 | h->next = next; |
| 2818 | *next = temp; |
| 2819 | } |
| 2820 | } |
| 2821 | #endif |
| 2822 | |
| 2823 | /* When running in the test harness, we want the hosts always to be in the same |
| 2824 | order so that the debugging output is the same and can be compared. Having a |
| 2825 | fixed set of "random" numbers doesn't actually achieve this, because the RRs |
| 2826 | come back from the resolver in a random order, so the non-random random numbers |
| 2827 | get used in a different order. We therefore have to sort the hosts that have |
| 2828 | the same MX values. We chose do to this by their name and then by IP address. |
| 2829 | The fact that the sort is slow matters not - this is testing only! */ |
| 2830 | |
| 2831 | if (running_in_test_harness) |
| 2832 | { |
| 2833 | BOOL done; |
| 2834 | do |
| 2835 | { |
| 2836 | done = TRUE; |
| 2837 | for (h = host; h != last; h = h->next) |
| 2838 | { |
| 2839 | int c = Ustrcmp(h->name, h->next->name); |
| 2840 | if (c == 0) c = Ustrcmp(h->address, h->next->address); |
| 2841 | if (h->mx == h->next->mx && c > 0) |
| 2842 | { |
| 2843 | host_item *next = h->next; |
| 2844 | host_item temp = *h; |
| 2845 | temp.next = next->next; |
| 2846 | *h = *next; |
| 2847 | h->next = next; |
| 2848 | *next = temp; |
| 2849 | done = FALSE; |
| 2850 | } |
| 2851 | } |
| 2852 | } |
| 2853 | while (!done); |
| 2854 | } |
| 2855 | |
| 2856 | /* Remove any duplicate IP addresses and then scan the list of hosts for any |
| 2857 | whose IP addresses are on the local host. If any are found, all hosts with the |
| 2858 | same or higher MX values are removed. However, if the local host has the lowest |
| 2859 | numbered MX, then HOST_FOUND_LOCAL is returned. Otherwise, if at least one host |
| 2860 | with an IP address is on the list, HOST_FOUND is returned. Otherwise, |
| 2861 | HOST_FIND_FAILED is returned, but in this case do not update the yield, as it |
| 2862 | might have been set to HOST_FIND_AGAIN just above here. If not, it will already |
| 2863 | be HOST_FIND_FAILED. */ |
| 2864 | |
| 2865 | host_remove_duplicates(host, &last); |
| 2866 | rc = host_scan_for_local_hosts(host, &last, removed); |
| 2867 | if (rc != HOST_FIND_FAILED) yield = rc; |
| 2868 | |
| 2869 | DEBUG(D_host_lookup) |
| 2870 | { |
| 2871 | if (fully_qualified_name != NULL) |
| 2872 | debug_printf("fully qualified name = %s\n", *fully_qualified_name); |
| 2873 | debug_printf("host_find_bydns yield = %s (%d); returned hosts:\n", |
| 2874 | (yield == HOST_FOUND)? "HOST_FOUND" : |
| 2875 | (yield == HOST_FOUND_LOCAL)? "HOST_FOUND_LOCAL" : |
| 2876 | (yield == HOST_FIND_AGAIN)? "HOST_FIND_AGAIN" : |
| 2877 | (yield == HOST_FIND_FAILED)? "HOST_FIND_FAILED" : "?", |
| 2878 | yield); |
| 2879 | for (h = host; h != last->next; h = h->next) |
| 2880 | { |
| 2881 | debug_printf(" %s %s MX=%d ", h->name, |
| 2882 | (h->address == NULL)? US"<null>" : h->address, h->mx); |
| 2883 | if (h->port != PORT_NONE) debug_printf("port=%d ", h->port); |
| 2884 | if (h->status >= hstatus_unusable) debug_printf("*"); |
| 2885 | debug_printf("\n"); |
| 2886 | } |
| 2887 | } |
| 2888 | |
| 2889 | return yield; |
| 2890 | } |
| 2891 | |
| 2892 | |
| 2893 | |
| 2894 | |
| 2895 | /************************************************* |
| 2896 | ************************************************** |
| 2897 | * Stand-alone test program * |
| 2898 | ************************************************** |
| 2899 | *************************************************/ |
| 2900 | |
| 2901 | #ifdef STAND_ALONE |
| 2902 | |
| 2903 | BOOL alldigits(uschar *buffer) |
| 2904 | { |
| 2905 | if (!isdigit(*buffer)) return FALSE; |
| 2906 | if (*buffer == '0' && buffer[1] == 'x') |
| 2907 | { |
| 2908 | buffer++; |
| 2909 | while (isxdigit(*(++buffer))); |
| 2910 | } |
| 2911 | else while (isdigit(*(++buffer))); |
| 2912 | return (*buffer == 0); |
| 2913 | } |
| 2914 | |
| 2915 | int main(int argc, char **cargv) |
| 2916 | { |
| 2917 | host_item h; |
| 2918 | int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A; |
| 2919 | BOOL byname = FALSE; |
| 2920 | BOOL qualify_single = TRUE; |
| 2921 | BOOL search_parents = FALSE; |
| 2922 | uschar **argv = USS cargv; |
| 2923 | uschar buffer[256]; |
| 2924 | |
| 2925 | primary_hostname = US""; |
| 2926 | store_pool = POOL_MAIN; |
| 2927 | debug_selector = D_host_lookup|D_interface; |
| 2928 | debug_file = stdout; |
| 2929 | debug_fd = fileno(debug_file); |
| 2930 | |
| 2931 | printf("Exim stand-alone host functions test\n"); |
| 2932 | |
| 2933 | host_find_interfaces(); |
| 2934 | debug_selector = D_host_lookup | D_dns; |
| 2935 | |
| 2936 | if (argc > 1) primary_hostname = argv[1]; |
| 2937 | |
| 2938 | /* So that debug level changes can be done first */ |
| 2939 | |
| 2940 | dns_init(qualify_single, search_parents); |
| 2941 | |
| 2942 | printf("Testing host lookup\n"); |
| 2943 | printf("> "); |
| 2944 | while (Ufgets(buffer, 256, stdin) != NULL) |
| 2945 | { |
| 2946 | int rc; |
| 2947 | int len = Ustrlen(buffer); |
| 2948 | uschar *fully_qualified_name; |
| 2949 | |
| 2950 | while (len > 0 && isspace(buffer[len-1])) len--; |
| 2951 | buffer[len] = 0; |
| 2952 | |
| 2953 | if (Ustrcmp(buffer, "q") == 0) break; |
| 2954 | |
| 2955 | if (Ustrcmp(buffer, "byname") == 0) byname = TRUE; |
| 2956 | else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE; |
| 2957 | else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A; |
| 2958 | else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX; |
| 2959 | else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV; |
| 2960 | else if (Ustrcmp(buffer, "srv+a") == 0) |
| 2961 | whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A; |
| 2962 | else if (Ustrcmp(buffer, "srv+mx") == 0) |
| 2963 | whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX; |
| 2964 | else if (Ustrcmp(buffer, "srv+mx+a") == 0) |
| 2965 | whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A; |
| 2966 | else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE; |
| 2967 | else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE; |
| 2968 | else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE; |
| 2969 | else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE; |
| 2970 | else if (Ustrncmp(buffer, "retrans", 7) == 0) |
| 2971 | { |
| 2972 | sscanf(CS(buffer+8), "%d", &dns_retrans); |
| 2973 | _res.retrans = dns_retrans; |
| 2974 | } |
| 2975 | else if (Ustrncmp(buffer, "retry", 5) == 0) |
| 2976 | { |
| 2977 | sscanf(CS(buffer+6), "%d", &dns_retry); |
| 2978 | _res.retry = dns_retry; |
| 2979 | } |
| 2980 | else if (alldigits(buffer)) |
| 2981 | { |
| 2982 | debug_selector = Ustrtol(buffer, NULL, 0); |
| 2983 | _res.options &= ~RES_DEBUG; |
| 2984 | DEBUG(D_resolver) _res.options |= RES_DEBUG; |
| 2985 | } |
| 2986 | else |
| 2987 | { |
| 2988 | int flags = whichrrs; |
| 2989 | |
| 2990 | h.name = buffer; |
| 2991 | h.next = NULL; |
| 2992 | h.mx = MX_NONE; |
| 2993 | h.port = PORT_NONE; |
| 2994 | h.status = hstatus_unknown; |
| 2995 | h.why = hwhy_unknown; |
| 2996 | h.address = NULL; |
| 2997 | |
| 2998 | if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE; |
| 2999 | if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS; |
| 3000 | |
| 3001 | rc = byname? |
| 3002 | host_find_byname(&h, NULL, &fully_qualified_name, TRUE) |
| 3003 | : |
| 3004 | host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL, |
| 3005 | &fully_qualified_name, NULL); |
| 3006 | |
| 3007 | if (rc == HOST_FIND_FAILED) printf("Failed\n"); |
| 3008 | else if (rc == HOST_FIND_AGAIN) printf("Again\n"); |
| 3009 | else if (rc == HOST_FOUND_LOCAL) printf("Local\n"); |
| 3010 | } |
| 3011 | |
| 3012 | printf("\n> "); |
| 3013 | } |
| 3014 | |
| 3015 | printf("Testing host_aton\n"); |
| 3016 | printf("> "); |
| 3017 | while (Ufgets(buffer, 256, stdin) != NULL) |
| 3018 | { |
| 3019 | int i; |
| 3020 | int x[4]; |
| 3021 | int len = Ustrlen(buffer); |
| 3022 | |
| 3023 | while (len > 0 && isspace(buffer[len-1])) len--; |
| 3024 | buffer[len] = 0; |
| 3025 | |
| 3026 | if (Ustrcmp(buffer, "q") == 0) break; |
| 3027 | |
| 3028 | len = host_aton(buffer, x); |
| 3029 | printf("length = %d ", len); |
| 3030 | for (i = 0; i < len; i++) |
| 3031 | { |
| 3032 | printf("%04x ", (x[i] >> 16) & 0xffff); |
| 3033 | printf("%04x ", x[i] & 0xffff); |
| 3034 | } |
| 3035 | printf("\n> "); |
| 3036 | } |
| 3037 | |
| 3038 | printf("\n"); |
| 3039 | |
| 3040 | printf("Testing host_name_lookup\n"); |
| 3041 | printf("> "); |
| 3042 | while (Ufgets(buffer, 256, stdin) != NULL) |
| 3043 | { |
| 3044 | int len = Ustrlen(buffer); |
| 3045 | while (len > 0 && isspace(buffer[len-1])) len--; |
| 3046 | buffer[len] = 0; |
| 3047 | if (Ustrcmp(buffer, "q") == 0) break; |
| 3048 | sender_host_address = buffer; |
| 3049 | sender_host_name = NULL; |
| 3050 | sender_host_aliases = NULL; |
| 3051 | host_lookup_msg = US""; |
| 3052 | host_lookup_failed = FALSE; |
| 3053 | if (host_name_lookup() == FAIL) /* Debug causes printing */ |
| 3054 | printf("Lookup failed:%s\n", host_lookup_msg); |
| 3055 | printf("\n> "); |
| 3056 | } |
| 3057 | |
| 3058 | printf("\n"); |
| 3059 | |
| 3060 | return 0; |
| 3061 | } |
| 3062 | #endif /* STAND_ALONE */ |
| 3063 | |
| 3064 | /* End of host.c */ |