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SoftEtherVPN/src/See/tcp_session.c
dnobori 749497dde0 v4.03-9408-rtm
2014-01-04 22:00:08 +09:00

297 lines
7.0 KiB
C
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/*
* Copyright (c) 2001 - 2003
* NetGroup, Politecnico di Torino (Italy)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Politecnico di Torino nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <GlobalConst.h>
#ifdef WIN32
#include "tme.h"
#include "tcp_session.h"
#endif
#ifdef __FreeBSD
#ifdef _KERNEL
#include <net/tme/tme.h>
#include <net/tme/tcp_session.h>
#else
#include <tme/tme.h>
#include <tme/tcp_session.h>
#endif
#endif
uint32 tcp_session(uint8 *block, uint32 pkt_size, TME_DATA *data, MEM_TYPE *mem_ex, uint8 *mem_data)
{
uint32 next_status;
uint32 direction=ULONG_AT(mem_data,12);
uint8 flags=mem_ex->buffer[25];
tcp_data *session=(tcp_data*)(block+data->key_len*4);
session->last_timestamp=session->timestamp_block;
session->timestamp_block.tv_sec=0x7fffffff;
if (direction==session->direction)
{
session->pkts_cln_to_srv++;
session->bytes_cln_to_srv+=pkt_size;
}
else
{
session->pkts_srv_to_cln++;
session->bytes_srv_to_cln+=pkt_size;
}
/* we use only thes four flags, we don't need PSH or URG */
flags&=(ACK|FIN|SYN|RST);
switch (session->status)
{
case ERROR_TCP:
next_status=ERROR_TCP;
break;
case UNKNOWN:
if (flags==SYN)
{
if (SW_ULONG_AT(mem_ex->buffer,20)!=0)
{
next_status=ERROR_TCP;
break;
}
next_status=SYN_RCV;
session->syn_timestamp=session->last_timestamp;
session->direction=direction;
session->seq_n_0_cln=SW_ULONG_AT(mem_ex->buffer,16);
}
else
next_status=UNKNOWN;
break;
case SYN_RCV:
if ((flags&RST)&&(direction!=session->direction))
{
next_status=CLOSED_RST;
break;
}
if ((flags==SYN)&&(direction==session->direction))
{ /* two syns... */
next_status=SYN_RCV;
session->seq_n_0_cln=SW_ULONG_AT(mem_ex->buffer,16);
break;
}
if ((flags==(SYN|ACK))&&(direction!=session->direction))
{
if (SW_ULONG_AT(mem_ex->buffer,20)!=session->seq_n_0_cln+1)
{
next_status=ERROR_TCP;
break;
}
next_status=SYN_ACK_RCV;
session->syn_ack_timestamp=session->last_timestamp;
session->seq_n_0_srv=SW_ULONG_AT(mem_ex->buffer,16);
session->ack_cln=session->seq_n_0_cln+1;
}
else
{
next_status=ERROR_TCP;
}
break;
case SYN_ACK_RCV:
if ((flags&ACK)&&(flags&RST)&&(direction==session->direction))
{
next_status=CLOSED_RST;
session->ack_srv=SW_ULONG_AT(mem_ex->buffer,20);
break;
}
if ((flags==ACK)&&(!(flags&(SYN|FIN|RST)))&&(direction==session->direction))
{
if (SW_ULONG_AT(mem_ex->buffer,20)!=session->seq_n_0_srv+1)
{
next_status=ERROR_TCP;
break;
}
next_status=ESTABLISHED;
session->ack_srv=session->seq_n_0_srv+1;
break;
}
if ((flags&ACK)&&(flags&SYN)&&(direction!=session->direction))
{
next_status=SYN_ACK_RCV;
break;
}
next_status=ERROR_TCP;
break;
case ESTABLISHED:
if (flags&SYN)
{
if ((flags&ACK)&&
(direction!=session->direction)&&
((session->ack_cln-SW_ULONG_AT(mem_ex->buffer,20))<MAX_WINDOW)
)
{ /* SYN_ACK duplicato */
next_status=ESTABLISHED;
break;
}
if ((!(flags&ACK))&&
(direction==session->direction)&&
(SW_ULONG_AT(mem_ex->buffer,16)==session->seq_n_0_cln)&&
(ULONG_AT(mem_ex->buffer,20)==0)
)
{ /* syn duplicato */
next_status=ESTABLISHED;
break;
}
next_status=ERROR_TCP;
break;
}
if (flags&ACK)
if (direction==session->direction)
{
uint32 new_ack=SW_ULONG_AT(mem_ex->buffer,20);
if (new_ack-session->ack_srv<MAX_WINDOW)
session->ack_srv=new_ack;
}
else
{
uint32 new_ack=SW_ULONG_AT(mem_ex->buffer,20);
if (new_ack-session->ack_cln<MAX_WINDOW)
session->ack_cln=new_ack;
}
if (flags&RST)
{
next_status=CLOSED_RST;
break;
}
if (flags&FIN)
if (direction==session->direction)
{ /* an hack to make all things work */
session->ack_cln=SW_ULONG_AT(mem_ex->buffer,16);
next_status=FIN_CLN_RCV;
break;
}
else
{
session->ack_srv=SW_ULONG_AT(mem_ex->buffer,16);
next_status=FIN_SRV_RCV;
break;
}
next_status=ESTABLISHED;
break;
case CLOSED_RST:
next_status=CLOSED_RST;
break;
case FIN_SRV_RCV:
if (flags&SYN)
{
next_status=ERROR_TCP;
break;
}
next_status=FIN_SRV_RCV;
if (flags&ACK)
{
uint32 new_ack=SW_ULONG_AT(mem_ex->buffer,20);
if (direction!=session->direction)
if ((new_ack-session->ack_cln)<MAX_WINDOW)
session->ack_cln=new_ack;
}
if (flags&RST)
next_status=CLOSED_RST;
else
if ((flags&FIN)&&(direction==session->direction))
{
session->ack_cln=SW_ULONG_AT(mem_ex->buffer,16);
next_status=CLOSED_FIN;
}
break;
case FIN_CLN_RCV:
if (flags&SYN)
{
next_status=ERROR_TCP;
break;
}
next_status=FIN_CLN_RCV;
if (flags&ACK)
{
uint32 new_ack=SW_ULONG_AT(mem_ex->buffer,20);
if (direction==session->direction)
if (new_ack-session->ack_srv<MAX_WINDOW)
session->ack_srv=new_ack;
}
if (flags&RST)
next_status=CLOSED_RST;
else
if ((flags&FIN)&&(direction!=session->direction))
{
session->ack_srv=SW_ULONG_AT(mem_ex->buffer,16);
next_status=CLOSED_FIN;
}
break;
case CLOSED_FIN:
next_status=CLOSED_FIN;
break;
default:
next_status=ERROR_TCP;
}
session->status=next_status;
if ((next_status==CLOSED_FIN)||(next_status==UNKNOWN)||(next_status==CLOSED_RST)||(next_status==ERROR_TCP))
session->timestamp_block=session->last_timestamp;
return TME_SUCCESS;
}
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