src/src/routers/iplookup.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2015 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8
   9 #include "../exim.h"
  10 #include "rf_functions.h"
  11 #include "iplookup.h"
  12
  13
  14 /* IP connection types */
  15
  16 #define ip_udp 0
  17 #define ip_tcp 1
  18
  19
  20 /* Options specific to the iplookup router. */
  21
  22 optionlist iplookup_router_options[] = {
  23   { "hosts",    opt_stringptr,
  24       (void *)(offsetof(iplookup_router_options_block, hosts)) },
  25   { "optional", opt_bool,
  26       (void *)(offsetof(iplookup_router_options_block, optional)) },
  27   { "port",     opt_int,
  28       (void *)(offsetof(iplookup_router_options_block, port)) },
  29   { "protocol", opt_stringptr,
  30       (void *)(offsetof(iplookup_router_options_block, protocol_name)) },
  31   { "query",    opt_stringptr,
  32       (void *)(offsetof(iplookup_router_options_block, query)) },
  33   { "reroute",  opt_stringptr,
  34       (void *)(offsetof(iplookup_router_options_block, reroute)) },
  35   { "response_pattern", opt_stringptr,
  36       (void *)(offsetof(iplookup_router_options_block, response_pattern)) },
  37   { "timeout",  opt_time,
  38       (void *)(offsetof(iplookup_router_options_block, timeout)) }
  39 };
  40
  41 /* Size of the options list. An extern variable has to be used so that its
  42 address can appear in the tables drtables.c. */
  43
  44 int iplookup_router_options_count =
  45   sizeof(iplookup_router_options)/sizeof(optionlist);
  46
  47
  48 #ifdef MACRO_PREDEF
  49
  50 /* Dummy entries */
  51 iplookup_router_options_block iplookup_router_option_defaults = {0};
  52 void iplookup_router_init(router_instance *rblock) {}
  53 int iplookup_router_entry(router_instance *rblock, address_item *addr,
  54   struct passwd *pw, int verify, address_item **addr_local,
  55   address_item **addr_remote, address_item **addr_new,
  56   address_item **addr_succeed) {return 0;}
  57
  58 #else   /*!MACRO_PREDEF*/
  59
  60
  61 /* Default private options block for the iplookup router. */
  62
  63 iplookup_router_options_block iplookup_router_option_defaults = {
  64   -1,       /* port */
  65   ip_udp,   /* protocol */
  66   5,        /* timeout */
  67   NULL,     /* protocol_name */
  68   NULL,     /* hosts */
  69   NULL,     /* query; NULL => local_part@domain */
  70   NULL,     /* response_pattern; NULL => don't apply regex */
  71   NULL,     /* reroute; NULL => just used returned data */
  72   NULL,     /* re_response_pattern; compiled pattern */
  73   FALSE     /* optional */
  74 };
  75
  76
  77
  78 /*************************************************
  79 *          Initialization entry point            *
  80 *************************************************/
  81
  82 /* Called for each instance, after its options have been read, to enable
  83 consistency checks to be done, or anything else that needs to be set up. */
  84
  85 void
  86 iplookup_router_init(router_instance *rblock)
  87 {
  88 iplookup_router_options_block *ob =
  89   (iplookup_router_options_block *)(rblock->options_block);
  90
  91 /* A port and a host list must be given */
  92
  93 if (ob->port < 0)
  94   log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s router:\n  "
  95     "a port must be specified", rblock->name);
  96
  97 if (ob->hosts == NULL)
  98   log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s router:\n  "
  99     "a host list must be specified", rblock->name);
 100
 101 /* Translate protocol name into value */
 102
 103 if (ob->protocol_name != NULL)
 104   {
 105   if (Ustrcmp(ob->protocol_name, "udp") == 0) ob->protocol = ip_udp;
 106   else if (Ustrcmp(ob->protocol_name, "tcp") == 0) ob->protocol = ip_tcp;
 107   else log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s router:\n  "
 108     "protocol not specified as udp or tcp", rblock->name);
 109   }
 110
 111 /* If a response pattern is given, compile it now to get the error early. */
 112
 113 if (ob->response_pattern != NULL)
 114   ob->re_response_pattern =
 115     regex_must_compile(ob->response_pattern, FALSE, TRUE);
 116 }
 117
 118
 119
 120 /*************************************************
 121 *              Main entry point                  *
 122 *************************************************/
 123
 124 /* See local README for interface details. This router returns:
 125
 126 DECLINE
 127   . pattern or identification match on returned data failed
 128
 129 DEFER
 130   . failed to expand the query or rerouting string
 131   . failed to create socket ("optional" not set)
 132   . failed to find a host, failed to connect, timed out ("optional" not set)
 133   . rerouting string is not in the form localpart@domain
 134   . verifying the errors address caused a deferment or a big disaster such
 135       as an expansion failure (rf_get_errors_address)
 136   . expanding a headers_{add,remove} string caused a deferment or another
 137       expansion error (rf_get_munge_headers)
 138
 139 PASS
 140   . failed to create socket ("optional" set)
 141   . failed to find a host, failed to connect, timed out ("optional" set)
 142
 143 OK
 144   . new address added to addr_new
 145 */
 146
 147 int
 148 iplookup_router_entry(
 149   router_instance *rblock,        /* data for this instantiation */
 150   address_item *addr,             /* address we are working on */
 151   struct passwd *pw,              /* passwd entry after check_local_user */
 152   int verify,                     /* v_none/v_recipient/v_sender/v_expn */
 153   address_item **addr_local,      /* add it to this if it's local */
 154   address_item **addr_remote,     /* add it to this if it's remote */
 155   address_item **addr_new,        /* put new addresses on here */
 156   address_item **addr_succeed)    /* put old address here on success */
 157 {
 158 uschar *query = NULL;
 159 uschar *reply;
 160 uschar *hostname, *reroute, *domain;
 161 const uschar *listptr;
 162 uschar host_buffer[256];
 163 host_item *host = store_get(sizeof(host_item));
 164 address_item *new_addr;
 165 iplookup_router_options_block *ob =
 166   (iplookup_router_options_block *)(rblock->options_block);
 167 const pcre *re = ob->re_response_pattern;
 168 int count, query_len, rc;
 169 int sep = 0;
 170
 171 addr_local = addr_local;    /* Keep picky compilers happy */
 172 addr_remote = addr_remote;
 173 addr_succeed = addr_succeed;
 174 pw = pw;
 175
 176 DEBUG(D_route) debug_printf("%s router called for %s: domain = %s\n",
 177   rblock->name, addr->address, addr->domain);
 178
 179 reply = store_get(256);
 180
 181 /* Build the query string to send. If not explicitly given, a default of
 182 "user@domain user@domain" is used. */
 183
 184 if (ob->query == NULL)
 185   query = string_sprintf("%s@%s %s@%s", addr->local_part, addr->domain,
 186     addr->local_part, addr->domain);
 187 else
 188   {
 189   query = expand_string(ob->query);
 190   if (query == NULL)
 191     {
 192     addr->message = string_sprintf("%s router: failed to expand %s: %s",
 193       rblock->name, ob->query, expand_string_message);
 194     return DEFER;
 195     }
 196   }
 197
 198 query_len = Ustrlen(query);
 199 DEBUG(D_route) debug_printf("%s router query is \"%s\"\n", rblock->name,
 200   string_printing(query));
 201
 202 /* Now connect to the required port for each of the hosts in turn, until a
 203 response it received. Initialization insists on the port being set and there
 204 being a host list. */
 205
 206 listptr = ob->hosts;
 207 while ((hostname = string_nextinlist(&listptr, &sep, host_buffer,
 208        sizeof(host_buffer))))
 209   {
 210   host_item *h;
 211
 212   DEBUG(D_route) debug_printf("calling host %s\n", hostname);
 213
 214   host->name = hostname;
 215   host->address = NULL;
 216   host->port = PORT_NONE;
 217   host->mx = MX_NONE;
 218   host->next = NULL;
 219
 220   if (string_is_ip_address(host->name, NULL) != 0)
 221     host->address = host->name;
 222   else
 223     {
 224 /*XXX might want dnssec request/require on an iplookup router? */
 225     int rc = host_find_byname(host, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, TRUE);
 226     if (rc == HOST_FIND_FAILED || rc == HOST_FIND_AGAIN) continue;
 227     }
 228
 229   /* Loop for possible multiple IP addresses for the given name. */
 230
 231   for (h = host; h; h = h->next)
 232     {
 233     int host_af, query_socket;
 234
 235     /* Skip any hosts for which we have no address */
 236
 237     if (!h->address) continue;
 238
 239     /* Create a socket, for UDP or TCP, as configured. IPv6 addresses are
 240     detected by checking for a colon in the address. */
 241
 242     host_af = (Ustrchr(h->address, ':') != NULL)? AF_INET6 : AF_INET;
 243
 244     query_socket = ip_socket(ob->protocol == ip_udp ? SOCK_DGRAM:SOCK_STREAM,
 245       host_af);
 246     if (query_socket < 0)
 247       {
 248       if (ob->optional) return PASS;
 249       addr->message = string_sprintf("failed to create socket in %s router",
 250         rblock->name);
 251       return DEFER;
 252       }
 253
 254     /* Connect to the remote host, under a timeout. In fact, timeouts can occur
 255     here only for TCP calls; for a UDP socket, "connect" always works (the
 256     router will timeout later on the read call). */
 257 /*XXX could take advantage of TFO */
 258
 259     if (ip_connect(query_socket, host_af, h->address,ob->port, ob->timeout,
 260                 ob->protocol == ip_udp ? NULL : &tcp_fastopen_nodata) < 0)
 261       {
 262       close(query_socket);
 263       DEBUG(D_route)
 264         debug_printf("connection to %s failed: %s\n", h->address,
 265           strerror(errno));
 266       continue;
 267       }
 268
 269     /* Send the query. If it fails, just continue with the next address. */
 270
 271     if (send(query_socket, query, query_len, 0) < 0)
 272       {
 273       DEBUG(D_route) debug_printf("send to %s failed\n", h->address);
 274       (void)close(query_socket);
 275       continue;
 276       }
 277
 278     /* Read the response and close the socket. If the read fails, try the
 279     next IP address. */
 280
 281     count = ip_recv(query_socket, reply, sizeof(reply) - 1, ob->timeout);
 282     (void)close(query_socket);
 283     if (count <= 0)
 284       {
 285       DEBUG(D_route) debug_printf("%s from %s\n", (errno == ETIMEDOUT)?
 286         "timed out" : "recv failed", h->address);
 287       *reply = 0;
 288       continue;
 289       }
 290
 291     /* Success; break the loop */
 292
 293     reply[count] = 0;
 294     DEBUG(D_route) debug_printf("%s router received \"%s\" from %s\n",
 295       rblock->name, string_printing(reply), h->address);
 296     break;
 297     }
 298
 299   /* If h == NULL we have tried all the IP addresses and failed on all of them,
 300   so we must continue to try more host names. Otherwise we have succeeded. */
 301
 302   if (h) break;
 303   }
 304
 305
 306 /* If hostname is NULL, we have failed to find any host, or failed to
 307 connect to any of the IP addresses, or timed out while reading or writing to
 308 those we have connected to. In all cases, we must pass if optional and
 309 defer otherwise. */
 310
 311 if (hostname == NULL)
 312   {
 313   DEBUG(D_route) debug_printf("%s router failed to get anything\n", rblock->name);
 314   if (ob->optional) return PASS;
 315   addr->message = string_sprintf("%s router: failed to communicate with any "
 316     "host", rblock->name);
 317   return DEFER;
 318   }
 319
 320
 321 /* If a response pattern was supplied, match the returned string against it. A
 322 failure to match causes the router to decline. After a successful match, the
 323 numerical variables for expanding the rerouted address are set up. */
 324
 325 if (re != NULL)
 326   {
 327   if (!regex_match_and_setup(re, reply, 0, -1))
 328     {
 329     DEBUG(D_route) debug_printf("%s router: %s failed to match response %s\n",
 330       rblock->name, ob->response_pattern, reply);
 331     return DECLINE;
 332     }
 333   }
 334
 335
 336 /* If no response pattern was supplied, set up $0 as the response up to the
 337 first white space (if any). Also, if no query was specified, check that what
 338 follows the white space matches user@domain. */
 339
 340 else
 341   {
 342   int n = 0;
 343   while (reply[n] != 0 && !isspace(reply[n])) n++;
 344   expand_nmax = 0;
 345   expand_nstring[0] = reply;
 346   expand_nlength[0] = n;
 347
 348   if (ob->query == NULL)
 349     {
 350     int nn = n;
 351     while (isspace(reply[nn])) nn++;
 352     if (Ustrcmp(query + query_len/2 + 1, reply+nn) != 0)
 353       {
 354       DEBUG(D_route) debug_printf("%s router: failed to match identification "
 355         "in response %s\n", rblock->name, reply);
 356       return DECLINE;
 357       }
 358     }
 359
 360   reply[n] = 0;  /* Terminate for the default case */
 361   }
 362
 363 /* If an explicit rerouting string is specified, expand it. Otherwise, use
 364 what was sent back verbatim. */
 365
 366 if (ob->reroute != NULL)
 367   {
 368   reroute = expand_string(ob->reroute);
 369   expand_nmax = -1;
 370   if (reroute == NULL)
 371     {
 372     addr->message = string_sprintf("%s router: failed to expand %s: %s",
 373       rblock->name, ob->reroute, expand_string_message);
 374     return DEFER;
 375     }
 376   }
 377 else reroute = reply;
 378
 379 /* We should now have a new address in the form user@domain. */
 380
 381 domain = Ustrchr(reroute, '@');
 382 if (domain == NULL)
 383   {
 384   log_write(0, LOG_MAIN, "%s router: reroute string %s is not of the form "
 385     "user@domain", rblock->name, reroute);
 386   addr->message = string_sprintf("%s router: reroute string %s is not of the "
 387     "form user@domain", rblock->name, reroute);
 388   return DEFER;
 389   }
 390
 391 /* Create a child address with the old one as parent. Put the new address on
 392 the chain of new addressess. */
 393
 394 new_addr = deliver_make_addr(reroute, TRUE);
 395 new_addr->parent = addr;
 396
 397 new_addr->prop = addr->prop;
 398
 399 if (addr->child_count == USHRT_MAX)
 400   log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s router generated more than %d "
 401     "child addresses for <%s>", rblock->name, USHRT_MAX, addr->address);
 402 addr->child_count++;
 403 new_addr->next = *addr_new;
 404 *addr_new = new_addr;
 405
 406 /* Set up the errors address, if any, and the additional and removeable headers
 407 for this new address. */
 408
 409 rc = rf_get_errors_address(addr, rblock, verify, &new_addr->prop.errors_address);
 410 if (rc != OK) return rc;
 411
 412 rc = rf_get_munge_headers(addr, rblock, &new_addr->prop.extra_headers,
 413   &new_addr->prop.remove_headers);
 414 if (rc != OK) return rc;
 415
 416 return OK;
 417 }
 418
 419 #endif   /*!MACRO_PREDEF*/
 420 /* End of routers/iplookup.c */