2 * ngIRCd -- The Next Generation IRC Daemon
3 * Copyright (c)2001-2003 by Alexander Barton (alex@barton.de)
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 * Please read the file COPYING, README and AUTHORS for more information.
11 * Asynchronous resolver
17 static char UNUSED id[] = "$Id: resolve.c,v 1.29 2008/02/26 22:04:17 fw Exp $";
25 #include <sys/socket.h>
26 #include <netinet/in.h>
44 static void Do_ResolveAddr PARAMS(( const ng_ipaddr_t *Addr, int Sock, int w_fd ));
45 static void Do_ResolveName PARAMS(( const char *Host, int w_fd ));
46 static bool register_callback PARAMS((RES_STAT *s, void (*cbfunc)(int, short)));
49 extern bool Conf_ConnectIPv4;
50 extern bool Conf_ConnectIPv6;
54 Resolver_fork(int *pipefds)
58 if (pipe(pipefds) != 0) {
59 Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
66 Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
82 * Resolve IP (asynchronous!).
85 Resolve_Addr(RES_STAT * s, const ng_ipaddr_t *Addr, int identsock,
86 void (*cbfunc) (int, short))
93 pid = Resolver_fork(pipefd);
95 Log(LOG_DEBUG, "Resolver for %s created (PID %d).", ng_ipaddr_tostr(Addr), pid);
98 s->resolver_fd = pipefd[0];
99 return register_callback(s, cbfunc);
100 } else if( pid == 0 ) {
102 Do_ResolveAddr( Addr, identsock, pipefd[1]);
103 Log_Exit_Resolver( );
111 * Resolve hostname (asynchronous!).
114 Resolve_Name( RES_STAT *s, const char *Host, void (*cbfunc)(int, short))
121 pid = Resolver_fork(pipefd);
125 Log( LOG_DEBUG, "Resolver for \"%s\" created (PID %d).", Host, pid );
128 s->resolver_fd = pipefd[0];
129 return register_callback(s, cbfunc);
130 } else if( pid == 0 ) {
132 Do_ResolveName(Host, pipefd[1]);
133 Log_Exit_Resolver( );
141 Resolve_Init(RES_STAT *s)
152 Get_Error( int H_Error )
154 /* Get error message for H_Error */
157 return "host not found";
159 return "name valid but no IP address defined";
161 return "name server error";
163 return "name server temporary not available";
165 return "unknown error";
168 #endif /* WANT_IPV6 */
171 /* Do "IDENT" (aka "AUTH") lookup and append result to resolved_addr array */
173 Do_IdentQuery(int identsock, array *resolved_addr)
182 Log_Resolver(LOG_DEBUG, "Doing IDENT lookup on socket %d ...", identsock);
184 res = ident_id( identsock, 10 );
186 Log_Resolver(LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"",
187 identsock, res ? res : "(NULL)" );
189 if (!res) /* no result */
191 if (!array_cats(resolved_addr, res))
192 Log_Resolver(LOG_WARNING, "Resolver: Cannot copy IDENT result: %s!", strerror(errno));
197 (void) resolved_addr;
203 * perform reverse DNS lookup and put result string into resbuf.
204 * If no hostname could be obtained, this function stores the string representation of
205 * the IP address in resbuf and returns false.
206 * @param IpAddr ip address to resolve
207 * @param resbuf result buffer to store DNS name/string representation of ip address
208 * @reslen size of result buffer (must be >= NGT_INET_ADDRSTRLEN)
209 * @return true if reverse lookup successful, false otherwise
212 ReverseLookup(const ng_ipaddr_t *IpAddr, char *resbuf, size_t reslen)
214 char tmp_ip_str[NG_INET_ADDRSTRLEN];
216 #ifdef HAVE_GETNAMEINFO
217 static const char funcname[]="getnameinfo";
222 res = getnameinfo((struct sockaddr *) IpAddr, ng_ipaddr_salen(IpAddr),
223 resbuf, reslen, NULL, 0, NI_NAMEREQD);
227 if (res == EAI_SYSTEM)
228 errmsg = strerror(errno);
230 errmsg = gai_strerror(res);
232 const struct sockaddr_in *Addr = (const struct sockaddr_in *) IpAddr;
234 static const char funcname[]="gethostbyaddr";
236 h = gethostbyaddr((char *)&Addr->sin_addr, sizeof(Addr->sin_addr), AF_INET);
238 if (strlcpy(resbuf, h->h_name, reslen) < reslen)
240 errmsg = "hostname too long";
243 errmsg = Get_Error(h_errno);
245 errmsg = "unknown error";
246 # endif /* h_errno */
248 #endif /* HAVE_GETNAMEINFO */
251 assert(reslen >= NG_INET_ADDRSTRLEN);
252 ng_ipaddr_tostr_r(IpAddr, tmp_ip_str);
254 Log_Resolver(LOG_WARNING, "%s: Can't resolve address \"%s\": %s",
255 funcname, tmp_ip_str, errmsg);
256 strlcpy(resbuf, tmp_ip_str, reslen);
262 * perform DNS lookup of given host name and fill IpAddr with a list of
263 * ip addresses associated with that name.
264 * ip addresses found are stored in the "array *IpAddr" argument (type ng_ipaddr_t)
265 * @param hostname The domain name to look up.
266 * @param IpAddr pointer to empty and initialized array to store results
267 * @return true if lookup successful, false if domain name not found
270 ForwardLookup(const char *hostname, array *IpAddr)
274 #ifdef HAVE_GETADDRINFO
276 struct addrinfo *a, *ai_results;
277 static struct addrinfo hints;
280 hints.ai_family = AF_INET;
282 #ifdef AI_ADDRCONFIG /* glibc has this, but not e.g. netbsd 4.0 */
283 hints.ai_flags = AI_ADDRCONFIG;
285 hints.ai_socktype = SOCK_STREAM;
286 hints.ai_protocol = IPPROTO_TCP;
289 assert(Conf_ConnectIPv6 || Conf_ConnectIPv4);
291 if (!Conf_ConnectIPv6)
292 hints.ai_family = AF_INET;
293 if (!Conf_ConnectIPv4)
294 hints.ai_family = AF_INET6;
296 res = getaddrinfo(hostname, NULL, &hints, &ai_results);
300 Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, strerror(errno));
303 Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, gai_strerror(res));
307 for (a = ai_results; a != NULL; a = a->ai_next) {
308 assert(a->ai_addrlen <= sizeof(addr));
310 if (a->ai_addrlen > sizeof(addr))
313 memcpy(&addr, a->ai_addr, a->ai_addrlen);
315 if (!array_catb(IpAddr, (char *)&addr, sizeof(addr)))
319 freeaddrinfo(ai_results);
322 struct hostent *h = gethostbyname(hostname);
326 Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, Get_Error(h_errno));
328 Log_Resolver(LOG_WARNING, "Can't resolve \"%s\"", hostname);
332 memset(&addr, 0, sizeof(addr));
334 addr.sin4.sin_family = AF_INET;
335 memcpy(&addr.sin4.sin_addr, h->h_addr, sizeof(struct in_addr));
337 return array_copyb(IpAddr, (char *)&addr, sizeof(addr));
338 #endif /* HAVE_GETADDRINFO */
343 Addr_in_list(const array *resolved_addr, const ng_ipaddr_t *Addr)
345 char tmp_ip_str[NG_INET_ADDRSTRLEN];
346 const ng_ipaddr_t *tmpAddrs = array_start(resolved_addr);
347 size_t len = array_length(resolved_addr, sizeof(*tmpAddrs));
353 if (ng_ipaddr_ipequal(Addr, tmpAddrs))
358 /* failed; print list of addresses */
359 ng_ipaddr_tostr_r(Addr, tmp_ip_str);
360 len = array_length(resolved_addr, sizeof(*tmpAddrs));
361 tmpAddrs = array_start(resolved_addr);
364 Log_Resolver(LOG_WARNING, "Address mismatch: %s != %s",
365 tmp_ip_str, ng_ipaddr_tostr(tmpAddrs));
375 Log_Forgery_NoIP(const char *ip, const char *host)
377 Log_Resolver(LOG_WARNING, "Possible forgery: %s resolved to %s "
378 "(which has no ip address)", ip, host);
382 Log_Forgery_WrongIP(const char *ip, const char *host)
384 Log_Resolver(LOG_WARNING,"Possible forgery: %s resolved to %s "
385 "(which points to different address)", ip, host);
390 ArrayWrite(int fd, const array *a)
392 size_t len = array_bytes(a);
393 const char *data = array_start(a);
397 if( (size_t)write(fd, data, len) != len )
398 Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!",
404 Do_ResolveAddr(const ng_ipaddr_t *Addr, int identsock, int w_fd)
406 /* Resolver sub-process: resolve IP address and write result into
408 char hostname[CLIENT_HOST_LEN];
409 char tmp_ip_str[NG_INET_ADDRSTRLEN];
413 array_init(&resolved_addr);
414 ng_ipaddr_tostr_r(Addr, tmp_ip_str);
416 Log_Resolver(LOG_DEBUG, "Now resolving %s ...", tmp_ip_str);
418 if (!ReverseLookup(Addr, hostname, sizeof(hostname)))
421 if (ForwardLookup(hostname, &resolved_addr)) {
422 if (!Addr_in_list(&resolved_addr, Addr)) {
423 Log_Forgery_WrongIP(tmp_ip_str, hostname);
424 strlcpy(hostname, tmp_ip_str, sizeof(hostname));
427 Log_Forgery_NoIP(tmp_ip_str, hostname);
428 strlcpy(hostname, tmp_ip_str, sizeof(hostname));
431 Log_Resolver(LOG_DEBUG, "Ok, translated %s to \"%s\".", tmp_ip_str, hostname);
434 len = strlen(hostname);
435 hostname[len] = '\n';
436 if (!array_copyb(&resolved_addr, hostname, ++len)) {
437 Log_Resolver(LOG_CRIT, "Resolver: Can't copy resolved name: %s!", strerror(errno));
438 array_free(&resolved_addr);
442 Do_IdentQuery(identsock, &resolved_addr);
444 ArrayWrite(w_fd, &resolved_addr);
446 array_free(&resolved_addr);
447 } /* Do_ResolveAddr */
451 Do_ResolveName( const char *Host, int w_fd )
453 /* Resolver sub-process: resolve name and write result into pipe
460 Log_Resolver(LOG_DEBUG, "Now resolving \"%s\" ...", Host);
462 array_init(&IpAddrs);
463 /* Resolve hostname */
464 if (!ForwardLookup(Host, &IpAddrs)) {
469 len = array_length(&IpAddrs, sizeof(*addr));
471 addr = array_start(&IpAddrs);
473 for (; len > 0; --len,addr++) {
474 Log_Resolver(LOG_DEBUG, "translated \"%s\" to %s.",
475 Host, ng_ipaddr_tostr(addr));
478 /* Write result into pipe to parent */
479 ArrayWrite(w_fd, &IpAddrs);
481 array_free(&IpAddrs);
482 } /* Do_ResolveName */
486 register_callback( RES_STAT *s, void (*cbfunc)(int, short))
488 assert(cbfunc != NULL);
490 assert(s->resolver_fd >= 0);
492 if (io_setnonblock(s->resolver_fd) &&
493 io_event_create(s->resolver_fd, IO_WANTREAD, cbfunc))
496 Log( LOG_CRIT, "Resolver: Could not register callback function: %s!", strerror(errno));
497 close(s->resolver_fd);
504 Resolve_Shutdown( RES_STAT *s)
509 assert(s->resolver_fd >= 0);
511 if (s->resolver_fd >= 0)
512 ret = io_close(s->resolver_fd);
520 * Read result of resolver sub-process from pipe
523 Resolve_Read( RES_STAT *s, void* readbuf, size_t buflen)
529 /* Read result from pipe */
530 bytes_read = read(s->resolver_fd, readbuf, buflen);
531 if (bytes_read < 0) {
535 Log( LOG_CRIT, "Resolver: Can't read result: %s!", strerror(errno));
539 else if (bytes_read == 0)
540 Log( LOG_DEBUG, "Resolver: Can't read result: EOF");
543 return (size_t)bytes_read;