303 lines
7.4 KiB
C
303 lines
7.4 KiB
C
/*
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VTun - Virtual Tunnel over TCP/IP network.
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Copyright (C) 1998-2008 Maxim Krasnyansky <max_mk@yahoo.com>
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VTun has been derived from VPPP package by Maxim Krasnyansky.
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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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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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*/
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/*
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* $Id: netlib.c,v 1.11.2.4 2009/03/29 10:44:02 mtbishop Exp $
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*/
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#include "config.h"
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#include "vtun_socks.h"
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include <stdarg.h>
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#include <sys/time.h>
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#include <sys/wait.h>
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#include <syslog.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#include <net/if.h>
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#include <errno.h>
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#ifdef HAVE_SYS_SOCKIO_H
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#include <sys/sockio.h>
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#endif
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#ifdef HAVE_NETINET_IN_H
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#include <netinet/in.h>
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#endif
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#ifdef HAVE_NETINET_IN_SYSTM_H
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#include <netinet/in_systm.h>
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#endif
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#ifdef HAVE_NETINET_IP_H
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#include <netinet/ip.h>
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#endif
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#ifdef HAVE_NETINET_TCP_H
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#include <netinet/tcp.h>
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#endif
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#ifdef HAVE_RESOLV_H
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#include <resolv.h>
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#endif
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#ifdef HAVE_ARPA_INET_H
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#include <arpa/inet.h>
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#endif
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#ifdef HAVE_NETDB_H
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#include <netdb.h>
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#endif
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#include "vtun.h"
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#include "lib.h"
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#include "netlib.h"
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/* Connect with timeout */
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int connect_t(int s, struct sockaddr *svr, time_t timeout)
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{
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#if defined(VTUN_SOCKS) && VTUN_SOCKS == 2
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/* Some SOCKS implementations don't support
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* non blocking connect */
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return connect(s,svr,sizeof(struct sockaddr));
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#else
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int sock_flags;
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fd_set fdset;
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struct timeval tv;
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tv.tv_usec=0; tv.tv_sec=timeout;
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sock_flags=fcntl(s,F_GETFL);
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if( fcntl(s,F_SETFL,O_NONBLOCK) < 0 )
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return -1;
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if( connect(s,svr,sizeof(struct sockaddr)) < 0 && errno != EINPROGRESS)
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return -1;
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FD_ZERO(&fdset);
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FD_SET(s,&fdset);
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if( select(s+1,NULL,&fdset,NULL,timeout?&tv:NULL) > 0 ){
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int l=sizeof(errno);
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errno=0;
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getsockopt(s,SOL_SOCKET,SO_ERROR,&errno,&l);
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} else
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errno=ETIMEDOUT;
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fcntl(s,F_SETFL,sock_flags);
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if( errno )
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return -1;
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return 0;
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#endif
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}
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/* Get interface address */
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unsigned long getifaddr(char * ifname)
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{
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struct sockaddr_in addr;
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struct ifreq ifr;
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int s;
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if( (s = socket(AF_INET, SOCK_DGRAM, 0)) == -1 )
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return -1;
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strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)-1);
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ifr.ifr_name[sizeof(ifr.ifr_name)-1]='\0';
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if( ioctl(s, SIOCGIFADDR, &ifr) < 0 ){
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close(s);
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return -1;
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}
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close(s);
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addr = *((struct sockaddr_in *) &ifr.ifr_addr);
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return addr.sin_addr.s_addr;
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}
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/*
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* Establish UDP session with host connected to fd(socket).
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* Returns connected UDP socket or -1 on error.
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*/
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int udp_session(struct vtun_host *host)
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{
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struct sockaddr_in saddr;
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short port;
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int s,opt;
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extern int is_rmt_fd_connected;
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if( (s=socket(AF_INET,SOCK_DGRAM,0))== -1 ){
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vtun_syslog(LOG_ERR,"Can't create socket");
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return -1;
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}
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opt=1;
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setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
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/* Set local address and port */
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local_addr(&saddr, host, 1);
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if( bind(s,(struct sockaddr *)&saddr,sizeof(saddr)) ){
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vtun_syslog(LOG_ERR,"Can't bind to the socket");
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return -1;
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}
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opt = sizeof(saddr);
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if( getsockname(s,(struct sockaddr *)&saddr,&opt) ){
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vtun_syslog(LOG_ERR,"Can't get socket name");
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return -1;
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}
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/* Write port of the new UDP socket */
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port = saddr.sin_port;
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if( write_n(host->rmt_fd,(char *)&port,sizeof(short)) < 0 ){
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vtun_syslog(LOG_ERR,"Can't write port number");
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return -1;
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}
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host->sopt.lport = htons(port);
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/* Read port of the other's end UDP socket */
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if( readn_t(host->rmt_fd,&port,sizeof(short),host->timeout) < 0 ){
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vtun_syslog(LOG_ERR,"Can't read port number %s", strerror(errno));
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return -1;
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}
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opt = sizeof(saddr);
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if( getpeername(host->rmt_fd,(struct sockaddr *)&saddr,&opt) ){
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vtun_syslog(LOG_ERR,"Can't get peer name");
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return -1;
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}
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saddr.sin_port = port;
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/* if the config says to delay the UDP connection, we wait for an
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incoming packet and then force a connection back. We need to
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put this here because we need to keep that incoming triggering
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packet and pass it back up the chain. */
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if (VTUN_USE_NAT_HACK(host))
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is_rmt_fd_connected=0;
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else {
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if( connect(s,(struct sockaddr *)&saddr,sizeof(saddr)) ){
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vtun_syslog(LOG_ERR,"Can't connect socket");
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return -1;
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}
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is_rmt_fd_connected=1;
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}
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host->sopt.rport = htons(port);
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/* Close TCP socket and replace with UDP socket */
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close(host->rmt_fd);
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host->rmt_fd = s;
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vtun_syslog(LOG_INFO,"UDP connection initialized");
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return s;
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}
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/* Set local address */
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int local_addr(struct sockaddr_in *addr, struct vtun_host *host, int con)
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{
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int opt;
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if( con ){
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/* Use address of the already connected socket. */
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opt = sizeof(struct sockaddr_in);
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if( getsockname(host->rmt_fd, (struct sockaddr *)addr, &opt) < 0 ){
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vtun_syslog(LOG_ERR,"Can't get local socket address");
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return -1;
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}
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} else {
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if (generic_addr(addr, &host->src_addr) < 0)
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return -1;
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}
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host->sopt.laddr = strdup(inet_ntoa(addr->sin_addr));
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return 0;
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}
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int server_addr(struct sockaddr_in *addr, struct vtun_host *host)
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{
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struct hostent * hent;
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memset(addr,0,sizeof(struct sockaddr_in));
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addr->sin_family = AF_INET;
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addr->sin_port = htons(vtun.bind_addr.port);
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/* Lookup server's IP address.
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* We do it on every reconnect because server's IP
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* address can be dynamic.
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*/
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if( !(hent = gethostbyname(vtun.svr_name)) ){
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vtun_syslog(LOG_ERR, "Can't resolv server address: %s", vtun.svr_name);
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return -1;
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}
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addr->sin_addr.s_addr = *(unsigned long *)hent->h_addr;
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host->sopt.raddr = strdup(inet_ntoa(addr->sin_addr));
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host->sopt.rport = vtun.bind_addr.port;
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return 0;
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}
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/* Set address by interface name, ip address or hostname */
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int generic_addr(struct sockaddr_in *addr, struct vtun_addr *vaddr)
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{
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struct hostent *hent;
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memset(addr, 0, sizeof(struct sockaddr_in));
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addr->sin_family = AF_INET;
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switch (vaddr->type) {
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case VTUN_ADDR_IFACE:
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if (!(addr->sin_addr.s_addr =
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getifaddr(vaddr->name))) {
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vtun_syslog(LOG_ERR,
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"Can't get address of interface %s",
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vaddr->name);
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return -1;
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}
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break;
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case VTUN_ADDR_NAME:
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if (!(hent = gethostbyname(vaddr->name))) {
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vtun_syslog(LOG_ERR,
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"Can't resolv local address %s",
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vaddr->name);
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return -1;
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}
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addr->sin_addr.s_addr = *(unsigned long *) hent->h_addr;
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break;
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default:
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addr->sin_addr.s_addr = INADDR_ANY;
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break;
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}
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if (vaddr->port)
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addr->sin_port = htons(vaddr->port);
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return 0;
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}
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