366 lines
8.4 KiB
C
366 lines
8.4 KiB
C
/*
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* ngIRCd -- The Next Generation IRC Daemon
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* Copyright (c)2001-2003 by Alexander Barton (alex@barton.de)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* Please read the file COPYING, README and AUTHORS for more information.
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*
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* Asynchronous resolver
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*/
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#include "portab.h"
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static char UNUSED id[] = "$Id: resolve.c,v 1.26 2006/12/17 22:50:51 fw Exp $";
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#include "imp.h"
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#include <assert.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#ifdef IDENTAUTH
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#ifdef HAVE_IDENT_H
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#include <ident.h>
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#endif
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#endif
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#include "conn.h"
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#include "defines.h"
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#include "log.h"
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#include "exp.h"
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#include "resolve.h"
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#include "io.h"
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static void Do_ResolveAddr PARAMS(( struct sockaddr_in *Addr, int Sock, int w_fd ));
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static void Do_ResolveName PARAMS(( const char *Host, int w_fd ));
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static bool register_callback PARAMS((RES_STAT *s, void (*cbfunc)(int, short)));
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#ifdef h_errno
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static char *Get_Error PARAMS(( int H_Error ));
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#endif
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static pid_t
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Resolver_fork(int *pipefds)
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{
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pid_t pid;
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if (pipe(pipefds) != 0) {
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Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
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return -1;
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}
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pid = fork();
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switch(pid) {
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case -1:
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Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
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close(pipefds[0]);
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close(pipefds[1]);
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return -1;
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case 0: /* child */
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close(pipefds[0]);
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Log_Init_Resolver( );
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return 0;
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}
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/* parent */
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close(pipefds[1]);
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return pid;
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}
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/**
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* Resolve IP (asynchronous!).
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*/
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GLOBAL bool
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Resolve_Addr(RES_STAT * s, struct sockaddr_in *Addr, int identsock,
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void (*cbfunc) (int, short))
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{
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int pipefd[2];
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pid_t pid;
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assert(s != NULL);
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pid = Resolver_fork(pipefd);
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if (pid > 0) {
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#ifdef DEBUG
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Log( LOG_DEBUG, "Resolver for %s created (PID %d).", inet_ntoa( Addr->sin_addr ), pid );
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#endif
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s->pid = pid;
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s->resolver_fd = pipefd[0];
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return register_callback(s, cbfunc);
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} else if( pid == 0 ) {
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/* Sub process */
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Do_ResolveAddr( Addr, identsock, pipefd[1]);
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Log_Exit_Resolver( );
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exit(0);
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}
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return false;
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} /* Resolve_Addr */
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/**
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* Resolve hostname (asynchronous!).
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*/
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GLOBAL bool
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Resolve_Name( RES_STAT *s, const char *Host, void (*cbfunc)(int, short))
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{
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int pipefd[2];
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pid_t pid;
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assert(s != NULL);
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pid = Resolver_fork(pipefd);
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if (pid > 0) {
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/* Main process */
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#ifdef DEBUG
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Log( LOG_DEBUG, "Resolver for \"%s\" created (PID %d).", Host, pid );
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#endif
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s->pid = pid;
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s->resolver_fd = pipefd[0];
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return register_callback(s, cbfunc);
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} else if( pid == 0 ) {
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/* Sub process */
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Do_ResolveName(Host, pipefd[1]);
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Log_Exit_Resolver( );
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exit(0);
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}
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return false;
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} /* Resolve_Name */
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GLOBAL void
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Resolve_Init(RES_STAT *s)
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{
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assert(s != NULL);
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s->resolver_fd = -1;
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s->pid = 0;
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}
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static void
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Do_ResolveAddr( struct sockaddr_in *Addr, int identsock, int w_fd )
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{
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/* Resolver sub-process: resolve IP address and write result into
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* pipe to parent. */
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char hostname[HOST_LEN];
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char ipstr[HOST_LEN];
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struct hostent *h;
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size_t len;
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struct in_addr *addr;
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char *ntoaptr;
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array resolved_addr;
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#ifdef IDENTAUTH
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char *res;
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#endif
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array_init(&resolved_addr);
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/* Resolve IP address */
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#ifdef DEBUG
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Log_Resolver( LOG_DEBUG, "Now resolving %s ...", inet_ntoa( Addr->sin_addr ));
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#endif
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h = gethostbyaddr( (char *)&Addr->sin_addr, sizeof( Addr->sin_addr ), AF_INET );
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if (!h) {
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#ifdef h_errno
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Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\": %s!", inet_ntoa( Addr->sin_addr ), Get_Error( h_errno ));
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#else
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Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\"!", inet_ntoa( Addr->sin_addr ));
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#endif
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strlcpy( hostname, inet_ntoa( Addr->sin_addr ), sizeof( hostname ));
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} else {
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strlcpy( hostname, h->h_name, sizeof( hostname ));
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h = gethostbyname( hostname );
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if ( h ) {
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if (memcmp(h->h_addr, &Addr->sin_addr, sizeof (struct in_addr))) {
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addr = (struct in_addr*) h->h_addr;
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strlcpy(ipstr, inet_ntoa(*addr), sizeof ipstr);
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ntoaptr = inet_ntoa( Addr->sin_addr );
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Log(LOG_WARNING,"Possible forgery: %s resolved to %s (which is at ip %s!)",
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ntoaptr, hostname, ipstr);
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strlcpy( hostname, ntoaptr, sizeof hostname);
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}
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} else {
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ntoaptr = inet_ntoa( Addr->sin_addr );
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Log(LOG_WARNING, "Possible forgery: %s resolved to %s (which has no ip address)",
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ntoaptr, hostname);
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strlcpy( hostname, ntoaptr, sizeof hostname);
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}
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}
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Log_Resolver( LOG_DEBUG, "Ok, translated %s to \"%s\".", inet_ntoa( Addr->sin_addr ), hostname );
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len = strlen( hostname );
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hostname[len] = '\n'; len++;
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if (!array_copyb(&resolved_addr, hostname, len )) {
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Log_Resolver( LOG_CRIT, "Resolver: Can't copy resolved name: %s!", strerror( errno ));
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close( w_fd );
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return;
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}
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#ifdef IDENTAUTH
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assert(identsock >= 0);
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if (identsock >= 0) {
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/* Do "IDENT" (aka "AUTH") lookup and append result to resolved_addr array */
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#ifdef DEBUG
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Log_Resolver( LOG_DEBUG, "Doing IDENT lookup on socket %d ...", identsock );
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#endif
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res = ident_id( identsock, 10 );
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#ifdef DEBUG
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Log_Resolver(LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"",
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identsock, res ? res : "(NULL)" );
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#endif
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if (res && !array_cats(&resolved_addr, res)) {
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Log_Resolver(LOG_WARNING, "Resolver: Cannot copy IDENT result: %s!", strerror(errno));
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/* omit ident and return hostname only */
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}
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if (res) free(res);
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}
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#else
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(void)identsock;
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#endif
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len = array_bytes(&resolved_addr);
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if( (size_t)write( w_fd, array_start(&resolved_addr), len) != len )
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Log_Resolver( LOG_CRIT, "Resolver: Can't write result to parent: %s!", strerror( errno ));
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close(w_fd);
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array_free(&resolved_addr);
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} /* Do_ResolveAddr */
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static void
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Do_ResolveName( const char *Host, int w_fd )
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{
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/* Resolver sub-process: resolve name and write result into pipe
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* to parent. */
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char ip[16];
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struct hostent *h;
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struct in_addr *addr;
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size_t len;
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Log_Resolver( LOG_DEBUG, "Now resolving \"%s\" ...", Host );
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/* Resolve hostname */
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h = gethostbyname( Host );
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if( h ) {
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addr = (struct in_addr *)h->h_addr;
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strlcpy( ip, inet_ntoa( *addr ), sizeof( ip ));
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} else {
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#ifdef h_errno
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Log_Resolver( LOG_WARNING, "Can't resolve \"%s\": %s!", Host, Get_Error( h_errno ));
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#else
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Log_Resolver( LOG_WARNING, "Can't resolve \"%s\"!", Host );
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#endif
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close(w_fd);
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return;
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}
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#ifdef DEBUG
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Log_Resolver( LOG_DEBUG, "Ok, translated \"%s\" to %s.", Host, ip );
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#endif
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/* Write result into pipe to parent */
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len = strlen( ip );
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if ((size_t)write( w_fd, ip, len ) != len) {
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Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
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close( w_fd );
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}
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} /* Do_ResolveName */
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#ifdef h_errno
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static char *
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Get_Error( int H_Error )
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{
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/* Get error message for H_Error */
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switch( H_Error )
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{
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case HOST_NOT_FOUND:
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return "host not found";
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case NO_DATA:
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return "name valid but no IP address defined";
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case NO_RECOVERY:
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return "name server error";
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case TRY_AGAIN:
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return "name server temporary not available";
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default:
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return "unknown error";
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}
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} /* Get_Error */
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#endif
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static bool
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register_callback( RES_STAT *s, void (*cbfunc)(int, short))
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{
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assert(cbfunc != NULL);
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assert(s != NULL);
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assert(s->resolver_fd >= 0);
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if (io_setnonblock(s->resolver_fd) &&
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io_event_create(s->resolver_fd, IO_WANTREAD, cbfunc))
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return true;
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Log( LOG_CRIT, "Resolver: Could not register callback function: %s!", strerror(errno));
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close(s->resolver_fd);
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Resolve_Init(s);
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return false;
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}
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GLOBAL bool
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Resolve_Shutdown( RES_STAT *s)
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{
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bool ret = false;
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assert(s != NULL);
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assert(s->resolver_fd >= 0);
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if (s->resolver_fd >= 0)
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ret = io_close(s->resolver_fd);
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Resolve_Init(s);
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return ret;
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}
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/**
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* Read result of resolver sub-process from pipe
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*/
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GLOBAL size_t
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Resolve_Read( RES_STAT *s, void* readbuf, size_t buflen)
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{
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ssize_t bytes_read;
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assert(buflen > 0);
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/* Read result from pipe */
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bytes_read = read(s->resolver_fd, readbuf, buflen);
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if (bytes_read < 0) {
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if (errno == EAGAIN)
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return 0;
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Log( LOG_CRIT, "Resolver: Can't read result: %s!", strerror(errno));
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bytes_read = 0;
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}
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#ifdef DEBUG
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else if (bytes_read == 0)
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Log( LOG_DEBUG, "Resolver: Can't read result: EOF");
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#endif
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Resolve_Shutdown(s);
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return (size_t)bytes_read;
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}
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/* -eof- */
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