1 /*
2  * ngIRCd -- The Next Generation IRC Daemon
3  * Copyright (c)2001,2002 by Alexander Barton (alex@barton.de)
4  *
5  * Dieses Programm ist freie Software. Sie koennen es unter den Bedingungen
6  * der GNU General Public License (GPL), wie von der Free Software Foundation
7  * herausgegeben, weitergeben und/oder modifizieren, entweder unter Version 2
8  * der Lizenz oder (wenn Sie es wuenschen) jeder spaeteren Version.
9  * Naehere Informationen entnehmen Sie bitter der Datei COPYING. Eine Liste
10  * der an ngIRCd beteiligten Autoren finden Sie in der Datei AUTHORS.
11  *
12  * $Id: resolve.c,v 1.3 2002/06/09 13:19:08 alex Exp $
13  *
14  * resolve.c: asyncroner Resolver
15  */
16 
17 
18 #include "portab.h"
19 
20 #include "imp.h"
21 #include <assert.h>
22 #include <errno.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <unistd.h>
26 #include <sys/socket.h>
27 #include <netinet/in.h>
28 #include <arpa/inet.h>
29 #include <netdb.h>
30 
31 #include "conn.h"
32 #include "defines.h"
33 #include "log.h"
34 
35 #include "exp.h"
36 #include "resolve.h"
37 
38 
39 LOCAL VOID Do_ResolveAddr PARAMS(( struct sockaddr_in *Addr, INT w_fd ));
40 LOCAL VOID Do_ResolveName PARAMS(( CHAR *Host, INT w_fd ));
41 
42 #ifdef h_errno
43 LOCAL CHAR *Get_Error PARAMS(( INT H_Error ));
44 #endif
45 
46 
47 GLOBAL VOID
48 Resolve_Init( VOID )
49 {
50 	/* Modul initialisieren */
51 
52 	FD_ZERO( &Resolver_FDs );
53 } /* Resolve_Init */
54 
55 
56 GLOBAL RES_STAT *
57 Resolve_Addr( struct sockaddr_in *Addr )
58 {
59 	/* IP (asyncron!) aufloesen. Bei Fehler, z.B. wenn der
60 	 * Child-Prozess nicht erzeugt werden kann, wird NULL geliefert.
61 	 * Der Host kann dann nicht aufgeloest werden. */
62 
63 	RES_STAT *s;
64 	INT pid;
65 
66 	/* Speicher anfordern */
67 	s = malloc( sizeof( RES_STAT ));
68 	if( ! s )
69 	{
70 		Log( LOG_EMERG, "Resolver: Can't allocate memory! [Resolve_Addr]" );
71 		return NULL;
72 	}
73 
74 	/* Pipe fuer Antwort initialisieren */
75 	if( pipe( s->pipe ) != 0 )
76 	{
77 		free( s );
78 		Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
79 		return NULL;
80 	}
81 
82 	/* Sub-Prozess erzeugen */
83 	pid = fork( );
84 	if( pid > 0 )
85 	{
86 		/* Haupt-Prozess */
87 		Log( LOG_DEBUG, "Resolver for %s created (PID %d).", inet_ntoa( Addr->sin_addr ), pid );
88 		FD_SET( s->pipe[0], &Resolver_FDs );
89 		if( s->pipe[0] > Conn_MaxFD ) Conn_MaxFD = s->pipe[0];
90 		s->pid = pid;
91 		return s;
92 	}
93 	else if( pid == 0 )
94 	{
95 		/* Sub-Prozess */
96 		Log_Init_Resolver( );
97 		Do_ResolveAddr( Addr, s->pipe[1] );
98 		Log_Exit_Resolver( );
99 		exit( 0 );
100 	}
101 	else
102 	{
103 		/* Fehler */
104 		free( s );
105 		Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
106 		return NULL;
107 	}
108 } /* Resolve_Addr */
109 
110 
111 GLOBAL RES_STAT *
112 Resolve_Name( CHAR *Host )
113 {
114 	/* Hostnamen (asyncron!) aufloesen. Bei Fehler, z.B. wenn der
115 	 * Child-Prozess nicht erzeugt werden kann, wird NULL geliefert.
116 	 * Der Host kann dann nicht aufgeloest werden. */
117 
118 	RES_STAT *s;
119 	INT pid;
120 
121 	/* Speicher anfordern */
122 	s = malloc( sizeof( RES_STAT ));
123 	if( ! s )
124 	{
125 		Log( LOG_EMERG, "Resolver: Can't allocate memory! [Resolve_Name]" );
126 		return NULL;
127 	}
128 
129 	/* Pipe fuer Antwort initialisieren */
130 	if( pipe( s->pipe ) != 0 )
131 	{
132 		free( s );
133 		Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
134 		return NULL;
135 	}
136 
137 	/* Sub-Prozess erzeugen */
138 	pid = fork( );
139 	if( pid > 0 )
140 	{
141 		/* Haupt-Prozess */
142 		Log( LOG_DEBUG, "Resolver for \"%s\" created (PID %d).", Host, pid );
143 		FD_SET( s->pipe[0], &Resolver_FDs );
144 		if( s->pipe[0] > Conn_MaxFD ) Conn_MaxFD = s->pipe[0];
145 		s->pid = pid;
146 		return s;
147 	}
148 	else if( pid == 0 )
149 	{
150 		/* Sub-Prozess */
151 		Log_Init_Resolver( );
152 		Do_ResolveName( Host, s->pipe[1] );
153 		Log_Exit_Resolver( );
154 		exit( 0 );
155 	}
156 	else
157 	{
158 		/* Fehler */
159 		free( s );
160 		Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
161 		return NULL;
162 	}
163 } /* Resolve_Name */
164 
165 
166 LOCAL VOID
167 Do_ResolveAddr( struct sockaddr_in *Addr, INT w_fd )
168 {
169 	/* Resolver Sub-Prozess: IP aufloesen und Ergebnis in Pipe schreiben. */
170 
171 	CHAR hostname[HOST_LEN];
172 	struct hostent *h;
173 
174 	Log_Resolver( LOG_DEBUG, "Now resolving %s ...", inet_ntoa( Addr->sin_addr ));
175 
176 	/* Namen aufloesen */
177 	h = gethostbyaddr( (CHAR *)&Addr->sin_addr, sizeof( Addr->sin_addr ), AF_INET );
178 	if( h ) strcpy( hostname, h->h_name );
179 	else
180 	{
181 #ifdef h_errno
182 		Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\": %s!", inet_ntoa( Addr->sin_addr ), Get_Error( h_errno ));
183 #else
184 		Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\"!", inet_ntoa( Addr->sin_addr ));
185 #endif	
186 		strcpy( hostname, inet_ntoa( Addr->sin_addr ));
187 	}
188 
189 	/* Antwort an Parent schreiben */
190 	if( write( w_fd, hostname, strlen( hostname ) + 1 ) != ( strlen( hostname ) + 1 ))
191 	{
192 		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
193 		close( w_fd );
194 		return;
195 	}
196 
197 	Log_Resolver( LOG_DEBUG, "Ok, translated %s to \"%s\".", inet_ntoa( Addr->sin_addr ), hostname );
198 } /* Do_ResolveAddr */
199 
200 
201 LOCAL VOID
202 Do_ResolveName( CHAR *Host, INT w_fd )
203 {
204 	/* Resolver Sub-Prozess: Name aufloesen und Ergebnis in Pipe schreiben. */
205 
206 	CHAR ip[16];
207 	struct hostent *h;
208 	struct in_addr *addr;
209 
210 	Log_Resolver( LOG_DEBUG, "Now resolving \"%s\" ...", Host );
211 
212 	/* Namen aufloesen */
213 	h = gethostbyname( Host );
214 	if( h )
215 	{
216 		addr = (struct in_addr *)h->h_addr;
217 		strcpy( ip, inet_ntoa( *addr ));
218 	}
219 	else
220 	{
221 #ifdef h_errno
222 		Log_Resolver( LOG_WARNING, "Can't resolve \"%s\": %s!", Host, Get_Error( h_errno ));
223 #else
224 		Log_Resolver( LOG_WARNING, "Can't resolve \"%s\"!", Host );
225 #endif
226 		strcpy( ip, "" );
227 	}
228 
229 	/* Antwort an Parent schreiben */
230 	if( write( w_fd, ip, strlen( ip ) + 1 ) != ( strlen( ip ) + 1 ))
231 	{
232 		Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
233 		close( w_fd );
234 		return;
235 	}
236 
237 	if( ip[0] ) Log_Resolver( LOG_DEBUG, "Ok, translated \"%s\" to %s.", Host, ip );
238 } /* Do_ResolveName */
239 
240 
241 #ifdef h_errno
242 
243 LOCAL CHAR *
244 Get_Error( INT H_Error )
245 {
246 	/* Fehlerbeschreibung fuer H_Error liefern */
247 
248 	switch( H_Error )
249 	{
250 		case HOST_NOT_FOUND:
251 			return "host not found";
252 		case NO_DATA:
253 			return "name valid but no IP address defined";
254 		case NO_RECOVERY:
255 			return "name server error";
256 		case TRY_AGAIN:
257 			return "name server temporary not available";
258 		default:
259 			return "unknown error";
260 	}
261 } /* Get_Error */
262 
263 #endif
264 
265 
266 /* -eof- */