2 * ngIRCd -- The Next Generation IRC Daemon
3 * Copyright (c)2001-2009 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
23 #include <sys/socket.h>
24 #include <netinet/in.h>
37 #include "ng_ipaddr.h"
44 static void Init_Subprocess PARAMS(( void ));
45 static void Do_ResolveAddr PARAMS(( const ng_ipaddr_t *Addr, int Sock, int w_fd ));
46 static void Do_ResolveName PARAMS(( const char *Host, int w_fd ));
49 extern bool Conf_ConnectIPv4;
50 extern bool Conf_ConnectIPv6;
55 * Resolve IP (asynchronous!).
58 Resolve_Addr(PROC_STAT * s, const ng_ipaddr_t *Addr, int identsock,
59 void (*cbfunc) (int, short))
66 pid = Proc_Fork(s, pipefd, cbfunc);
68 LogDebug("Resolver for %s created (PID %d).", ng_ipaddr_tostr(Addr), pid);
70 } else if( pid == 0 ) {
73 Do_ResolveAddr( Addr, identsock, pipefd[1]);
74 Log_Exit_Subprocess("Resolver");
82 * Resolve hostname (asynchronous!).
85 Resolve_Name( PROC_STAT *s, const char *Host, void (*cbfunc)(int, short))
92 pid = Proc_Fork(s, pipefd, cbfunc);
96 Log( LOG_DEBUG, "Resolver for \"%s\" created (PID %d).", Host, pid );
99 } else if( pid == 0 ) {
102 Do_ResolveName(Host, pipefd[1]);
103 Log_Exit_Subprocess("Resolver");
111 * Initialize forked resolver subprocess.
114 Init_Subprocess(void)
116 signal(SIGTERM, Proc_GenericSignalHandler);
117 Log_Init_Subprocess("Resolver");
121 #if !defined(HAVE_GETADDRINFO) || !defined(HAVE_GETNAMEINFO)
122 #if !defined(WANT_IPV6) && defined(h_errno)
124 Get_Error( int H_Error )
126 /* Get error message for H_Error */
129 return "host not found";
131 return "name valid but no IP address defined";
133 return "name server error";
135 return "name server temporary not available";
137 return "unknown error";
143 /* Do "IDENT" (aka "AUTH") lookup and append result to resolved_addr array */
145 Do_IdentQuery(int identsock, array *resolved_addr)
154 Log_Subprocess(LOG_DEBUG, "Doing IDENT lookup on socket %d ...",
157 res = ident_id( identsock, 10 );
159 Log_Subprocess(LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"",
160 identsock, res ? res : "(NULL)");
162 if (!res) /* no result */
164 if (!array_cats(resolved_addr, res))
165 Log_Subprocess(LOG_WARNING,
166 "Resolver: Cannot copy IDENT result: %s!",
172 (void) resolved_addr;
178 * perform reverse DNS lookup and put result string into resbuf.
179 * If no hostname could be obtained, this function stores the string representation of
180 * the IP address in resbuf and returns false.
181 * @param IpAddr ip address to resolve
182 * @param resbuf result buffer to store DNS name/string representation of ip address
183 * @param reslen size of result buffer (must be >= NGT_INET_ADDRSTRLEN)
184 * @return true if reverse lookup successful, false otherwise
187 ReverseLookup(const ng_ipaddr_t *IpAddr, char *resbuf, size_t reslen)
189 char tmp_ip_str[NG_INET_ADDRSTRLEN];
191 #ifdef HAVE_GETNAMEINFO
192 static const char funcname[]="getnameinfo";
197 res = getnameinfo((struct sockaddr *) IpAddr, ng_ipaddr_salen(IpAddr),
198 resbuf, (socklen_t)reslen, NULL, 0, NI_NAMEREQD);
202 if (res == EAI_SYSTEM)
203 errmsg = strerror(errno);
205 errmsg = gai_strerror(res);
207 const struct sockaddr_in *Addr = (const struct sockaddr_in *) IpAddr;
209 static const char funcname[]="gethostbyaddr";
211 h = gethostbyaddr((char *)&Addr->sin_addr, sizeof(Addr->sin_addr), AF_INET);
213 if (strlcpy(resbuf, h->h_name, reslen) < reslen)
215 errmsg = "hostname too long";
218 errmsg = Get_Error(h_errno);
220 errmsg = "unknown error";
221 # endif /* h_errno */
223 #endif /* HAVE_GETNAMEINFO */
226 assert(reslen >= NG_INET_ADDRSTRLEN);
227 ng_ipaddr_tostr_r(IpAddr, tmp_ip_str);
229 Log_Subprocess(LOG_WARNING, "%s: Can't resolve address \"%s\": %s",
230 funcname, tmp_ip_str, errmsg);
231 strlcpy(resbuf, tmp_ip_str, reslen);
237 * perform DNS lookup of given host name and fill IpAddr with a list of
238 * ip addresses associated with that name.
239 * ip addresses found are stored in the "array *IpAddr" argument (type ng_ipaddr_t)
240 * @param hostname The domain name to look up.
241 * @param IpAddr pointer to empty and initialized array to store results
242 * @return true if lookup successful, false if domain name not found
245 ForwardLookup(const char *hostname, array *IpAddr)
249 #ifdef HAVE_GETADDRINFO
251 struct addrinfo *a, *ai_results;
252 static struct addrinfo hints;
255 hints.ai_family = AF_INET;
257 #ifdef AI_ADDRCONFIG /* glibc has this, but not e.g. netbsd 4.0 */
258 hints.ai_flags = AI_ADDRCONFIG;
260 hints.ai_socktype = SOCK_STREAM;
261 hints.ai_protocol = IPPROTO_TCP;
264 assert(Conf_ConnectIPv6 || Conf_ConnectIPv4);
266 if (!Conf_ConnectIPv6)
267 hints.ai_family = AF_INET;
268 if (!Conf_ConnectIPv4)
269 hints.ai_family = AF_INET6;
271 memset(&addr, 0, sizeof(addr));
273 res = getaddrinfo(hostname, NULL, &hints, &ai_results);
277 Log_Subprocess(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, strerror(errno));
280 Log_Subprocess(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, gai_strerror(res));
284 for (a = ai_results; a != NULL; a = a->ai_next) {
285 assert(a->ai_addrlen <= sizeof(addr));
287 if (a->ai_addrlen > sizeof(addr))
290 memcpy(&addr, a->ai_addr, a->ai_addrlen);
292 if (!array_catb(IpAddr, (char *)&addr, sizeof(addr)))
296 freeaddrinfo(ai_results);
299 struct hostent *h = gethostbyname(hostname);
303 Log_Subprocess(LOG_WARNING, "Can't resolve \"%s\": %s",
304 hostname, Get_Error(h_errno));
306 Log_Subprocess(LOG_WARNING, "Can't resolve \"%s\"", hostname);
310 memset(&addr, 0, sizeof(addr));
312 addr.sin4.sin_family = AF_INET;
313 memcpy(&addr.sin4.sin_addr, h->h_addr, sizeof(struct in_addr));
315 return array_copyb(IpAddr, (char *)&addr, sizeof(addr));
316 #endif /* HAVE_GETADDRINFO */
321 Addr_in_list(const array *resolved_addr, const ng_ipaddr_t *Addr)
323 char tmp_ip_str[NG_INET_ADDRSTRLEN];
324 const ng_ipaddr_t *tmpAddrs = array_start(resolved_addr);
325 size_t len = array_length(resolved_addr, sizeof(*tmpAddrs));
331 if (ng_ipaddr_ipequal(Addr, tmpAddrs))
336 /* failed; print list of addresses */
337 ng_ipaddr_tostr_r(Addr, tmp_ip_str);
338 len = array_length(resolved_addr, sizeof(*tmpAddrs));
339 tmpAddrs = array_start(resolved_addr);
342 Log_Subprocess(LOG_WARNING, "Address mismatch: %s != %s",
343 tmp_ip_str, ng_ipaddr_tostr(tmpAddrs));
353 Log_Forgery_NoIP(const char *ip, const char *host)
355 Log_Subprocess(LOG_WARNING, "Possible forgery: %s resolved to %s "
356 "(which has no ip address)", ip, host);
360 Log_Forgery_WrongIP(const char *ip, const char *host)
362 Log_Subprocess(LOG_WARNING,"Possible forgery: %s resolved to %s "
363 "(which points to different address)", ip, host);
368 ArrayWrite(int fd, const array *a)
370 size_t len = array_bytes(a);
371 const char *data = array_start(a);
375 if( (size_t)write(fd, data, len) != len )
376 Log_Subprocess( LOG_CRIT, "Resolver: Can't write to parent: %s!",
382 Do_ResolveAddr(const ng_ipaddr_t *Addr, int identsock, int w_fd)
384 /* Resolver sub-process: resolve IP address and write result into
386 char hostname[CLIENT_HOST_LEN];
387 char tmp_ip_str[NG_INET_ADDRSTRLEN];
391 array_init(&resolved_addr);
392 ng_ipaddr_tostr_r(Addr, tmp_ip_str);
394 Log_Subprocess(LOG_DEBUG, "Now resolving %s ...", tmp_ip_str);
396 if (!ReverseLookup(Addr, hostname, sizeof(hostname)))
399 if (ForwardLookup(hostname, &resolved_addr)) {
400 if (!Addr_in_list(&resolved_addr, Addr)) {
401 Log_Forgery_WrongIP(tmp_ip_str, hostname);
402 strlcpy(hostname, tmp_ip_str, sizeof(hostname));
405 Log_Forgery_NoIP(tmp_ip_str, hostname);
406 strlcpy(hostname, tmp_ip_str, sizeof(hostname));
409 Log_Subprocess(LOG_DEBUG, "Ok, translated %s to \"%s\".", tmp_ip_str, hostname);
412 len = strlen(hostname);
413 hostname[len] = '\n';
414 if (!array_copyb(&resolved_addr, hostname, ++len)) {
415 Log_Subprocess(LOG_CRIT,
416 "Resolver: Can't copy resolved name: %s!",
418 array_free(&resolved_addr);
422 Do_IdentQuery(identsock, &resolved_addr);
424 ArrayWrite(w_fd, &resolved_addr);
426 array_free(&resolved_addr);
427 } /* Do_ResolveAddr */
431 Do_ResolveName( const char *Host, int w_fd )
433 /* Resolver sub-process: resolve name and write result into pipe
440 Log_Subprocess(LOG_DEBUG, "Now resolving \"%s\" ...", Host);
442 array_init(&IpAddrs);
443 /* Resolve hostname */
444 if (!ForwardLookup(Host, &IpAddrs)) {
449 len = array_length(&IpAddrs, sizeof(*addr));
451 addr = array_start(&IpAddrs);
453 for (; len > 0; --len,addr++) {
454 Log_Subprocess(LOG_DEBUG, "translated \"%s\" to %s.",
455 Host, ng_ipaddr_tostr(addr));
458 /* Write result into pipe to parent */
459 ArrayWrite(w_fd, &IpAddrs);
461 array_free(&IpAddrs);
462 } /* Do_ResolveName */
466 * Read result of resolver sub-process from pipe
469 Resolve_Read( PROC_STAT *s, void* readbuf, size_t buflen)
475 /* Read result from pipe */
476 bytes_read = read(Proc_GetPipeFd(s), readbuf, buflen);
477 if (bytes_read < 0) {
481 Log( LOG_CRIT, "Resolver: Can't read result: %s!", strerror(errno));
485 else if (bytes_read == 0)
486 Log( LOG_DEBUG, "Resolver: Can't read result: EOF");
489 return (size_t)bytes_read;