1 /*
2  * ngIRCd -- The Next Generation IRC Daemon
3  * Copyright (c)2001-2003 by Alexander Barton (alex@barton.de)
4  *
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.
10  *
11  * Asynchronous resolver
12  */
13 
14 
15 #include "portab.h"
16 
17 static char UNUSED id[] = "$Id: resolve.c,v 1.9 2004/05/11 00:01:11 alex Exp $";
18 
19 #include "imp.h"
20 #include <assert.h>
21 #include <errno.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <unistd.h>
25 #include <sys/socket.h>
26 #include <netinet/in.h>
27 #include <arpa/inet.h>
28 #include <netdb.h>
29 
30 #ifdef IDENTAUTH
31 #ifdef HAVE_IDENT_H
32 #include <ident.h>
33 #endif
34 #endif
35 
36 #include "conn.h"
37 #include "defines.h"
38 #include "log.h"
39 
40 #include "exp.h"
41 #include "resolve.h"
42 
43 
44 #ifdef IDENTAUTH
45 LOCAL VOID Do_ResolveAddr PARAMS(( struct sockaddr_in *Addr, INT Sock, INT w_fd ));
46 #else
47 LOCAL VOID Do_ResolveAddr PARAMS(( struct sockaddr_in *Addr, INT w_fd ));
48 #endif
49 
50 LOCAL VOID Do_ResolveName PARAMS(( CHAR *Host, INT w_fd ));
51 
52 #ifdef h_errno
53 LOCAL CHAR *Get_Error PARAMS(( INT H_Error ));
54 #endif
55 
56 
57 GLOBAL VOID
58 Resolve_Init( VOID )
59 {
60 	/* Initialize module */
61 
62 	FD_ZERO( &Resolver_FDs );
63 } /* Resolve_Init */
64 
65 
66 #ifdef IDENTAUTH
67 GLOBAL RES_STAT *
68 Resolve_Addr( struct sockaddr_in *Addr, int Sock )
69 #else
70 GLOBAL RES_STAT *
71 Resolve_Addr( struct sockaddr_in *Addr )
72 #endif
73 {
74 	/* Resolve IP (asynchronous!). On errors, e.g. if the child process
75 	 * can't be forked, this functions returns NULL. */
76 
77 	RES_STAT *s;
78 	INT pid;
79 
80 	/* Allocate memory */
81 	s = (RES_STAT *)malloc( sizeof( RES_STAT ));
82 	if( ! s )
83 	{
84 		Log( LOG_EMERG, "Resolver: Can't allocate memory! [Resolve_Addr]" );
85 		return NULL;
86 	}
87 
88 	/* Initialize pipe for result */
89 	if( pipe( s->pipe ) != 0 )
90 	{
91 		free( s );
92 		Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
93 		return NULL;
94 	}
95 
96 	/* For sub-process */
97 	pid = fork( );
98 	if( pid > 0 )
99 	{
100 		/* Main process */
101 		Log( LOG_DEBUG, "Resolver for %s created (PID %d).", inet_ntoa( Addr->sin_addr ), pid );
102 		FD_SET( s->pipe[0], &Resolver_FDs );
103 		if( s->pipe[0] > Conn_MaxFD ) Conn_MaxFD = s->pipe[0];
104 		s->pid = pid;
105 		s->stage = 0;
106 		s->bufpos = 0;
107 		return s;
108 	}
109 	else if( pid == 0 )
110 	{
111 		/* Sub process */
112 		Log_Init_Resolver( );
113 #ifdef IDENTAUTH
114 		Do_ResolveAddr( Addr, Sock, s->pipe[1] );
115 #else
116 		Do_ResolveAddr( Addr, s->pipe[1] );
117 #endif
118 		Log_Exit_Resolver( );
119 		exit( 0 );
120 	}
121 	else
122 	{
123 		/* Error! */
124 		free( s );
125 		Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
126 		return NULL;
127 	}
128 } /* Resolve_Addr */
129 
130 
131 GLOBAL RES_STAT *
132 Resolve_Name( CHAR *Host )
133 {
134 	/* Resolve hostname (asynchronous!). On errors, e.g. if the child
135 	 * process can't be forked, this functions returns NULL. */
136 
137 	RES_STAT *s;
138 	INT pid;
139 
140 	/* Allocate memory */
141 	s = (RES_STAT *)malloc( sizeof( RES_STAT ));
142 	if( ! s )
143 	{
144 		Log( LOG_EMERG, "Resolver: Can't allocate memory! [Resolve_Name]" );
145 		return NULL;
146 	}
147 
148 	/* Initialize the pipe for the result */
149 	if( pipe( s->pipe ) != 0 )
150 	{
151 		free( s );
152 		Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
153 		return NULL;
154 	}
155 
156 	/* Fork sub-process */
157 	pid = fork( );
158 	if( pid > 0 )
159 	{
160 		/* Main process */
161 		Log( LOG_DEBUG, "Resolver for \"%s\" created (PID %d).", Host, pid );
162 		FD_SET( s->pipe[0], &Resolver_FDs );
163 		if( s->pipe[0] > Conn_MaxFD ) Conn_MaxFD = s->pipe[0];
164 		s->pid = pid;
165 		s->stage = 0;
166 		s->bufpos = 0;
167 		return s;
168 	}
169 	else if( pid == 0 )
170 	{
171 		/* Sub process */
172 		Log_Init_Resolver( );
173 		Do_ResolveName( Host, s->pipe[1] );
174 		Log_Exit_Resolver( );
175 		exit( 0 );
176 	}
177 	else
178 	{
179 		/* Error! */
180 		free( s );
181 		Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
182 		return NULL;
183 	}
184 } /* Resolve_Name */
185 
186 
187 #ifdef IDENTAUTH
188 LOCAL VOID
189 Do_ResolveAddr( struct sockaddr_in *Addr, int Sock, INT w_fd )
190 #else
191 LOCAL VOID
192 Do_ResolveAddr( struct sockaddr_in *Addr, INT w_fd )
193 #endif
194 {
195 	/* Resolver sub-process: resolve IP address and write result into
196 	 * pipe to parent. */
197 
198 	CHAR hostname[HOST_LEN];
199 	struct hostent *h;
200 	INT len;
201 #ifdef IDENTAUTH
202 	CHAR *res;
203 #endif
204 
205 	/* Resolve IP address */
206 	Log_Resolver( LOG_DEBUG, "Now resolving %s ...", inet_ntoa( Addr->sin_addr ));
207 	h = gethostbyaddr( (CHAR *)&Addr->sin_addr, sizeof( Addr->sin_addr ), AF_INET );
208 	if( h ) strlcpy( hostname, h->h_name, sizeof( hostname ));
209 	else
210 	{
211 #ifdef h_errno
212 		Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\": %s!", inet_ntoa( Addr->sin_addr ), Get_Error( h_errno ));
213 #else
214 		Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\"!", inet_ntoa( Addr->sin_addr ));
215 #endif	
216 		strlcpy( hostname, inet_ntoa( Addr->sin_addr ), sizeof( hostname ));
217 	}
218 	Log_Resolver( LOG_DEBUG, "Ok, translated %s to \"%s\".", inet_ntoa( Addr->sin_addr ), hostname );
219 
220 	/* Write resolver result into pipe to parent */
221 	len = strlen( hostname ); 
222 	hostname[len] = '\n'; len++;
223 	if( (size_t)write( w_fd, hostname, len ) != (size_t)len )
224 	{
225 		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
226 		close( w_fd );
227 		return;
228 	}
229 
230 #ifdef IDENTAUTH
231 	/* Do "IDENT" (aka "AUTH") lookup and write result to parent */
232 	Log_Resolver( LOG_DEBUG, "Doing IDENT lookup on socket %d ...", Sock );
233 	res = ident_id( Sock, 10 );
234 	Log_Resolver( LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"", Sock, res ? res : "" );
235 
236 	/* Write IDENT result into pipe to parent */
237 	len = strlen( res ? res : "" );
238 	if( res != NULL ) res[len] = '\n';
239 	len++;
240 	if( (size_t)write( w_fd, res ? res : "\n", len ) != (size_t)len )
241 	{
242 		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent (IDENT): %s!", strerror( errno ));
243 		close( w_fd );
244 	}
245 	free( res );
246 #endif
247 } /* Do_ResolveAddr */
248 
249 
250 LOCAL VOID
251 Do_ResolveName( CHAR *Host, INT w_fd )
252 {
253 	/* Resolver sub-process: resolve name and write result into pipe
254 	 * to parent. */
255 
256 	CHAR ip[16];
257 	struct hostent *h;
258 	struct in_addr *addr;
259 	INT len;
260 
261 	Log_Resolver( LOG_DEBUG, "Now resolving \"%s\" ...", Host );
262 
263 	/* Resolve hostname */
264 	h = gethostbyname( Host );
265 	if( h )
266 	{
267 		addr = (struct in_addr *)h->h_addr;
268 		strlcpy( ip, inet_ntoa( *addr ), sizeof( ip ));
269 	}
270 	else
271 	{
272 #ifdef h_errno
273 		Log_Resolver( LOG_WARNING, "Can't resolve \"%s\": %s!", Host, Get_Error( h_errno ));
274 #else
275 		Log_Resolver( LOG_WARNING, "Can't resolve \"%s\"!", Host );
276 #endif
277 		strcpy( ip, "" );
278 	}
279 	if( ip[0] ) Log_Resolver( LOG_DEBUG, "Ok, translated \"%s\" to %s.", Host, ip );
280 
281 	/* Write result into pipe to parent */
282 	len = strlen( ip );
283 	ip[len] = '\n'; len++;
284 	if( (size_t)write( w_fd, ip, len ) != (size_t)len )
285 	{
286 		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
287 		close( w_fd );
288 	}
289 } /* Do_ResolveName */
290 
291 
292 #ifdef h_errno
293 
294 LOCAL CHAR *
295 Get_Error( INT H_Error )
296 {
297 	/* Get error message for H_Error */
298 
299 	switch( H_Error )
300 	{
301 		case HOST_NOT_FOUND:
302 			return "host not found";
303 		case NO_DATA:
304 			return "name valid but no IP address defined";
305 		case NO_RECOVERY:
306 			return "name server error";
307 		case TRY_AGAIN:
308 			return "name server temporary not available";
309 		default:
310 			return "unknown error";
311 	}
312 } /* Get_Error */
313 
314 #endif
315 
316 
317 /* -eof- */