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vtun/netlib.c

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/*
VTun - Virtual Tunnel over TCP/IP network.
Copyright (C) 1998-2000 Maxim Krasnyansky <max_mk@yahoo.com>
VTun has been derived from VPPP package by Maxim Krasnyansky.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
*/
/*
* $Id: netlib.c,v 1.11.2.1 2007/06/29 05:26:35 mtbishop Exp $
*/
#include "config.h"
#include "vtun_socks.h"
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdarg.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <errno.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETINET_IN_SYSTM_H
#include <netinet/in_systm.h>
#endif
#ifdef HAVE_NETINET_IP_H
#include <netinet/ip.h>
#endif
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h>
#endif
#ifdef HAVE_RESOLV_H
#include <resolv.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#include "vtun.h"
#include "lib.h"
#include "netlib.h"
/* Connect with timeout */
int connect_t(int s, struct sockaddr *svr, time_t timeout)
{
#if defined(VTUN_SOCKS) && VTUN_SOCKS == 2
/* Some SOCKS implementations don't support
* non blocking connect */
return connect(s,svr,sizeof(struct sockaddr));
#else
int sock_flags;
fd_set fdset;
struct timeval tv;
tv.tv_usec=0; tv.tv_sec=timeout;
sock_flags=fcntl(s,F_GETFL);
if( fcntl(s,F_SETFL,O_NONBLOCK) < 0 )
return -1;
if( connect(s,svr,sizeof(struct sockaddr)) < 0 && errno != EINPROGRESS)
return -1;
FD_ZERO(&fdset);
FD_SET(s,&fdset);
if( select(s+1,NULL,&fdset,NULL,timeout?&tv:NULL) > 0 ){
int l=sizeof(errno);
errno=0;
getsockopt(s,SOL_SOCKET,SO_ERROR,&errno,&l);
} else
errno=ETIMEDOUT;
fcntl(s,F_SETFL,sock_flags);
if( errno )
return -1;
return 0;
#endif
}
/* Get interface address */
unsigned long getifaddr(char * ifname)
{
struct sockaddr_in addr;
struct ifreq ifr;
int s;
if( (s = socket(AF_INET, SOCK_DGRAM, 0)) == -1 )
return -1;
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)-1);
ifr.ifr_name[sizeof(ifr.ifr_name)-1]='\0';
if( ioctl(s, SIOCGIFADDR, &ifr) < 0 ){
close(s);
return -1;
}
close(s);
addr = *((struct sockaddr_in *) &ifr.ifr_addr);
return addr.sin_addr.s_addr;
}
/*
* Establish UDP session with host connected to fd(socket).
* Returns connected UDP socket or -1 on error.
*/
int udp_session(struct vtun_host *host)
{
struct sockaddr_in saddr;
short port;
int s,opt;
if( (s=socket(AF_INET,SOCK_DGRAM,0))== -1 ){
vtun_syslog(LOG_ERR,"Can't create socket");
return -1;
}
opt=1;
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
/* Set local address and port */
local_addr(&saddr, host, 1);
if( bind(s,(struct sockaddr *)&saddr,sizeof(saddr)) ){
vtun_syslog(LOG_ERR,"Can't bind to the socket");
return -1;
}
opt = sizeof(saddr);
if( getsockname(s,(struct sockaddr *)&saddr,&opt) ){
vtun_syslog(LOG_ERR,"Can't get socket name");
return -1;
}
/* Write port of the new UDP socket */
port = saddr.sin_port;
if( write_n(host->rmt_fd,(char *)&port,sizeof(short)) < 0 ){
vtun_syslog(LOG_ERR,"Can't write port number");
return -1;
}
host->sopt.lport = htons(port);
/* Read port of the other's end UDP socket */
if( readn_t(host->rmt_fd,&port,sizeof(short),host->timeout) < 0 ){
vtun_syslog(LOG_ERR,"Can't read port number %s", strerror(errno));
return -1;
}
opt = sizeof(saddr);
if( getpeername(host->rmt_fd,(struct sockaddr *)&saddr,&opt) ){
vtun_syslog(LOG_ERR,"Can't get peer name");
return -1;
}
saddr.sin_port = port;
if( connect(s,(struct sockaddr *)&saddr,sizeof(saddr)) ){
vtun_syslog(LOG_ERR,"Can't connect socket");
return -1;
}
host->sopt.rport = htons(port);
/* Close TCP socket and replace with UDP socket */
close(host->rmt_fd);
host->rmt_fd = s;
vtun_syslog(LOG_INFO,"UDP connection initialized");
return s;
}
/* Set local address */
int local_addr(struct sockaddr_in *addr, struct vtun_host *host, int con)
{
int opt;
if( con ){
/* Use address of the already connected socket. */
opt = sizeof(struct sockaddr_in);
if( getsockname(host->rmt_fd, (struct sockaddr *)addr, &opt) < 0 ){
vtun_syslog(LOG_ERR,"Can't get local socket address");
return -1;
}
} else {
if (generic_addr(addr, &host->src_addr) < 0)
return -1;
}
host->sopt.laddr = strdup(inet_ntoa(addr->sin_addr));
return 0;
}
int server_addr(struct sockaddr_in *addr, struct vtun_host *host)
{
struct hostent * hent;
memset(addr,0,sizeof(struct sockaddr_in));
addr->sin_family = AF_INET;
addr->sin_port = htons(vtun.bind_addr.port);
/* Lookup server's IP address.
* We do it on every reconnect because server's IP
* address can be dynamic.
*/
if( !(hent = gethostbyname(vtun.svr_name)) ){
vtun_syslog(LOG_ERR, "Can't resolv server address: %s", vtun.svr_name);
return -1;
}
addr->sin_addr.s_addr = *(unsigned long *)hent->h_addr;
host->sopt.raddr = strdup(inet_ntoa(addr->sin_addr));
host->sopt.rport = vtun.bind_addr.port;
return 0;
}
/* Set address by interface name, ip address or hostname */
int generic_addr(struct sockaddr_in *addr, struct vtun_addr *vaddr)
{
struct hostent *hent;
memset(addr, 0, sizeof(struct sockaddr_in));
addr->sin_family = AF_INET;
switch (vaddr->type) {
case VTUN_ADDR_IFACE:
if (!(addr->sin_addr.s_addr =
getifaddr(vaddr->name))) {
vtun_syslog(LOG_ERR,
"Can't get address of interface %s",
vaddr->name);
return -1;
}
break;
case VTUN_ADDR_NAME:
if (!(hent = gethostbyname(vaddr->name))) {
vtun_syslog(LOG_ERR,
"Can't resolv local address %s",
vaddr->name);
return -1;
}
addr->sin_addr.s_addr = *(unsigned long *) hent->h_addr;
break;
default:
addr->sin_addr.s_addr = INADDR_ANY;
break;
}
if (vaddr->port)
addr->sin_port = htons(vaddr->port);
return 0;
}
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