1 /*
2  * ngIRCd -- The Next Generation IRC Daemon
3  * Copyright (c)2001,2002 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 1.5 2002/12/26 17:04:54 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 #include "conn.h"
31 #include "defines.h"
32 #include "log.h"
33 
34 #include "exp.h"
35 #include "resolve.h"
36 
37 
38 LOCAL VOID Do_ResolveAddr PARAMS(( struct sockaddr_in *Addr, INT w_fd ));
39 LOCAL VOID Do_ResolveName PARAMS(( CHAR *Host, INT w_fd ));
40 
41 #ifdef h_errno
42 LOCAL CHAR *Get_Error PARAMS(( INT H_Error ));
43 #endif
44 
45 
46 GLOBAL VOID
47 Resolve_Init( VOID )
48 {
49 	/* Modul initialisieren */
50 
51 	FD_ZERO( &Resolver_FDs );
52 } /* Resolve_Init */
53 
54 
55 GLOBAL RES_STAT *
56 Resolve_Addr( struct sockaddr_in *Addr )
57 {
58 	/* IP (asyncron!) aufloesen. Bei Fehler, z.B. wenn der
59 	 * Child-Prozess nicht erzeugt werden kann, wird NULL geliefert.
60 	 * Der Host kann dann nicht aufgeloest werden. */
61 
62 	RES_STAT *s;
63 	INT pid;
64 
65 	/* Speicher anfordern */
66 	s = malloc( sizeof( RES_STAT ));
67 	if( ! s )
68 	{
69 		Log( LOG_EMERG, "Resolver: Can't allocate memory! [Resolve_Addr]" );
70 		return NULL;
71 	}
72 
73 	/* Pipe fuer Antwort initialisieren */
74 	if( pipe( s->pipe ) != 0 )
75 	{
76 		free( s );
77 		Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
78 		return NULL;
79 	}
80 
81 	/* Sub-Prozess erzeugen */
82 	pid = fork( );
83 	if( pid > 0 )
84 	{
85 		/* Haupt-Prozess */
86 		Log( LOG_DEBUG, "Resolver for %s created (PID %d).", inet_ntoa( Addr->sin_addr ), pid );
87 		FD_SET( s->pipe[0], &Resolver_FDs );
88 		if( s->pipe[0] > Conn_MaxFD ) Conn_MaxFD = s->pipe[0];
89 		s->pid = pid;
90 		return s;
91 	}
92 	else if( pid == 0 )
93 	{
94 		/* Sub-Prozess */
95 		Log_Init_Resolver( );
96 		Do_ResolveAddr( Addr, s->pipe[1] );
97 		Log_Exit_Resolver( );
98 		exit( 0 );
99 	}
100 	else
101 	{
102 		/* Fehler */
103 		free( s );
104 		Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
105 		return NULL;
106 	}
107 } /* Resolve_Addr */
108 
109 
110 GLOBAL RES_STAT *
111 Resolve_Name( CHAR *Host )
112 {
113 	/* Hostnamen (asyncron!) aufloesen. Bei Fehler, z.B. wenn der
114 	 * Child-Prozess nicht erzeugt werden kann, wird NULL geliefert.
115 	 * Der Host kann dann nicht aufgeloest werden. */
116 
117 	RES_STAT *s;
118 	INT pid;
119 
120 	/* Speicher anfordern */
121 	s = malloc( sizeof( RES_STAT ));
122 	if( ! s )
123 	{
124 		Log( LOG_EMERG, "Resolver: Can't allocate memory! [Resolve_Name]" );
125 		return NULL;
126 	}
127 
128 	/* Pipe fuer Antwort initialisieren */
129 	if( pipe( s->pipe ) != 0 )
130 	{
131 		free( s );
132 		Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
133 		return NULL;
134 	}
135 
136 	/* Sub-Prozess erzeugen */
137 	pid = fork( );
138 	if( pid > 0 )
139 	{
140 		/* Haupt-Prozess */
141 		Log( LOG_DEBUG, "Resolver for \"%s\" created (PID %d).", Host, pid );
142 		FD_SET( s->pipe[0], &Resolver_FDs );
143 		if( s->pipe[0] > Conn_MaxFD ) Conn_MaxFD = s->pipe[0];
144 		s->pid = pid;
145 		return s;
146 	}
147 	else if( pid == 0 )
148 	{
149 		/* Sub-Prozess */
150 		Log_Init_Resolver( );
151 		Do_ResolveName( Host, s->pipe[1] );
152 		Log_Exit_Resolver( );
153 		exit( 0 );
154 	}
155 	else
156 	{
157 		/* Fehler */
158 		free( s );
159 		Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
160 		return NULL;
161 	}
162 } /* Resolve_Name */
163 
164 
165 LOCAL VOID
166 Do_ResolveAddr( struct sockaddr_in *Addr, INT w_fd )
167 {
168 	/* Resolver Sub-Prozess: IP aufloesen und Ergebnis in Pipe schreiben. */
169 
170 	CHAR hostname[HOST_LEN];
171 	struct hostent *h;
172 
173 	Log_Resolver( LOG_DEBUG, "Now resolving %s ...", inet_ntoa( Addr->sin_addr ));
174 
175 	/* Namen aufloesen */
176 	h = gethostbyaddr( (CHAR *)&Addr->sin_addr, sizeof( Addr->sin_addr ), AF_INET );
177 	if( h ) strlcpy( hostname, h->h_name, sizeof( hostname ));
178 	else
179 	{
180 #ifdef h_errno
181 		Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\": %s!", inet_ntoa( Addr->sin_addr ), Get_Error( h_errno ));
182 #else
183 		Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\"!", inet_ntoa( Addr->sin_addr ));
184 #endif	
185 		strlcpy( hostname, inet_ntoa( Addr->sin_addr ), sizeof( hostname ));
186 	}
187 
188 	/* Antwort an Parent schreiben */
189 	if( write( w_fd, hostname, strlen( hostname ) + 1 ) != ( strlen( hostname ) + 1 ))
190 	{
191 		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
192 		close( w_fd );
193 		return;
194 	}
195 
196 	Log_Resolver( LOG_DEBUG, "Ok, translated %s to \"%s\".", inet_ntoa( Addr->sin_addr ), hostname );
197 } /* Do_ResolveAddr */
198 
199 
200 LOCAL VOID
201 Do_ResolveName( CHAR *Host, INT w_fd )
202 {
203 	/* Resolver Sub-Prozess: Name aufloesen und Ergebnis in Pipe schreiben. */
204 
205 	CHAR ip[16];
206 	struct hostent *h;
207 	struct in_addr *addr;
208 
209 	Log_Resolver( LOG_DEBUG, "Now resolving \"%s\" ...", Host );
210 
211 	/* Namen aufloesen */
212 	h = gethostbyname( Host );
213 	if( h )
214 	{
215 		addr = (struct in_addr *)h->h_addr;
216 		strlcpy( ip, inet_ntoa( *addr ), sizeof( ip ));
217 	}
218 	else
219 	{
220 #ifdef h_errno
221 		Log_Resolver( LOG_WARNING, "Can't resolve \"%s\": %s!", Host, Get_Error( h_errno ));
222 #else
223 		Log_Resolver( LOG_WARNING, "Can't resolve \"%s\"!", Host );
224 #endif
225 		strcpy( ip, "" );
226 	}
227 
228 	/* Antwort an Parent schreiben */
229 	if( write( w_fd, ip, strlen( ip ) + 1 ) != ( strlen( ip ) + 1 ))
230 	{
231 		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
232 		close( w_fd );
233 		return;
234 	}
235 
236 	if( ip[0] ) Log_Resolver( LOG_DEBUG, "Ok, translated \"%s\" to %s.", Host, ip );
237 } /* Do_ResolveName */
238 
239 
240 #ifdef h_errno
241 
242 LOCAL CHAR *
243 Get_Error( INT H_Error )
244 {
245 	/* Fehlerbeschreibung fuer H_Error liefern */
246 
247 	switch( H_Error )
248 	{
249 		case HOST_NOT_FOUND:
250 			return "host not found";
251 		case NO_DATA:
252 			return "name valid but no IP address defined";
253 		case NO_RECOVERY:
254 			return "name server error";
255 		case TRY_AGAIN:
256 			return "name server temporary not available";
257 		default:
258 			return "unknown error";
259 	}
260 } /* Get_Error */
261 
262 #endif
263 
264 
265 /* -eof- */