112 lines
2.5 KiB
C
112 lines
2.5 KiB
C
/*
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VTun - Virtual Tunnel over TCP/IP network.
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Copyright (C) 1998-2000 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: udp_proto.c,v 1.10.2.1 2007/06/29 05:27:09 mtbishop Exp $
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*/
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#include "config.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/uio.h>
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#include <errno.h>
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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/udp.h>
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#endif
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#include "vtun.h"
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#include "lib.h"
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/* Functions to read/write UDP frames. */
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int udp_write(int fd, char *buf, int len)
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{
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register char *ptr;
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register int wlen;
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ptr = buf - sizeof(short);
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*((unsigned short *)ptr) = htons(len);
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len = (len & VTUN_FSIZE_MASK) + sizeof(short);
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while( 1 ){
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if( (wlen = write(fd, ptr, len)) < 0 ){
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if( errno == EAGAIN || errno == EINTR )
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continue;
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if( errno == ENOBUFS )
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return 0;
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}
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/* Even if we wrote only part of the frame
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* we can't use second write since it will produce
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* another UDP frame */
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return wlen;
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}
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}
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int udp_read(int fd, char *buf)
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{
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unsigned short hdr, flen;
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struct iovec iv[2];
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register int rlen;
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/* Read frame */
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iv[0].iov_len = sizeof(short);
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iv[0].iov_base = (char *) &hdr;
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iv[1].iov_len = VTUN_FRAME_SIZE + VTUN_FRAME_OVERHEAD;
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iv[1].iov_base = buf;
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while( 1 ){
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if( (rlen = readv(fd, iv, 2)) < 0 ){
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if( errno == EAGAIN || errno == EINTR )
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continue;
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else
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return rlen;
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}
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hdr = ntohs(hdr);
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flen = hdr & VTUN_FSIZE_MASK;
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if( rlen < 2 || (rlen-2) != flen )
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return VTUN_BAD_FRAME;
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return hdr;
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}
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}
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