ev_dg.c

开源的防火墙代码

/* Copyright (c) 2002-2005 Vladislav Goncharov.
*
* Redistribution and use in source forms, with and without modification,
* are permitted provided that this entire comment appears intact.
*
* Redistribution in binary form may occur without any restrictions.
*
* This software is provided ``AS IS'' without any warranties of any kind.
*/

// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil -*- (for GNU Emacs)
//
// $Id: ev_dg.c,v 1.6 2003/09/04 15:20:09 dev Exp $

/*
* This file contains TDI_EVENT_RECEIVE_DATAGRAM handler
*/

#include <ntddk.h>
#include <tdikrnl.h>
#include "sock.h"

#include "events.h"
#include "filter.h"
#include "memtrack.h"
#include "obj_tbl.h"
#include "sids.h"
#include "tdi_fw.h"

//----------------------------------------------------------------------------

/*
* TDI_EVENT_RECEIVE_DATAGRAM handler
*/

NTSTATUS tdi_event_receive_datagram(
				      IN PVOID TdiEventContext,
				      IN LONG SourceAddressLength,
				      IN PVOID SourceAddress,
				      IN LONG OptionsLength,
				      IN PVOID Options,
				      IN ULONG ReceiveDatagramFlags,
				      IN ULONG BytesIndicated,
				      IN ULONG BytesAvailable,
				      OUT ULONG *BytesTaken,
				      IN PVOID Tsdu,
				      OUT PIRP *IoRequestPacket)
{
	TDI_EVENT_CONTEXT *ctx = (TDI_EVENT_CONTEXT *)TdiEventContext;
	struct ot_entry *ote_addr = NULL;
	KIRQL irql;
	TA_ADDRESS *remote_addr, *local_addr;
	NTSTATUS status;
	int ipproto, result = FILTER_DENY;
	struct flt_request request;
	struct flt_rule rule;
	
	// get local address of address object
	
	memset(&request, 0, sizeof(request));
	ote_addr = ot_find_fileobj(ctx->fileobj, &irql);
	if (ote_addr == NULL)
		{
		KdPrint(("[tdi_fw] tdi_receive_datagram: ot_find_fileobj(0x%x)!\n", ctx->fileobj));
		goto done;
		}
	
	KdPrint(("[tdi_fw] tdi_event_receive_datagram: addrobj 0x%x\n", ctx->fileobj));
	
	// check device object: UDP or RawIP
	if (get_original_devobj(ote_addr->devobj, &ipproto) == NULL ||
		(ipproto != IPPROTO_UDP && ipproto != IPPROTO_IP))
		{
		// unknown device object!
		KdPrint(("[tdi_fw] tdi_event_receive_datagram: unknown DeviceObject 0x%x!\n",
			ote_addr));
		goto done;
		}
	
	local_addr = (TA_ADDRESS *)(ote_addr->local_addr);
	remote_addr = ((TRANSPORT_ADDRESS *)SourceAddress)->Address;
	
	KdPrint(("[tdi_fw] tdi_event_receive_datagram(pid:%u): %x:%u -> %x:%u\n",
		ote_addr->pid,
		ntohl(((TDI_ADDRESS_IP *)(remote_addr->Address))->in_addr),
	ntohs(((TDI_ADDRESS_IP *)(remote_addr->Address))->sin_port),
	ntohl(((TDI_ADDRESS_IP *)(local_addr->Address))->in_addr),
	ntohs(((TDI_ADDRESS_IP *)(local_addr->Address))->sin_port)));
	
	// call quick filter for datagram
	request.struct_size = sizeof(request);
	
	request.type = TYPE_DATAGRAM;
	request.direction = DIRECTION_IN;
	request.proto = ipproto;
	request.pid = ote_addr->pid;
	
	// get user SID & attributes (can't call get_current_sid_a at DISPATCH_LEVEL)
	if ((request.sid_a = copy_sid_a(ote_addr->sid_a, ote_addr->sid_a_size)) != NULL)
		request.sid_a_size = ote_addr->sid_a_size;
	
	memcpy(&request.addr.from, &remote_addr->AddressType, sizeof(struct sockaddr));
	memcpy(&request.addr.to, &local_addr->AddressType, sizeof(struct sockaddr));
	request.addr.len = sizeof(struct sockaddr_in);
	
	memset(&rule, 0, sizeof(rule));
	
	result = quick_filter(&request, &rule);
	
	memcpy(request.log_rule_id, rule.rule_id, RULE_ID_SIZE);
	
	if (rule.log >= RULE_LOG_LOG)
		{
		ULONG bytes = BytesAvailable;
		
		// traffic stats
		KeAcquireSpinLockAtDpcLevel(&g_traffic_guard);
		
		g_traffic[TRAFFIC_TOTAL_IN] += bytes;
		
		if (rule.log >= RULE_LOG_COUNT)
			{
			request.log_bytes_in = bytes;
			
			g_traffic[TRAFFIC_COUNTED_IN] += bytes;
			
			}
		else
			request.log_bytes_in = (ULONG)-1;
		
		KeReleaseSpinLockFromDpcLevel(&g_traffic_guard);
		
		log_request(&request);
		}
	
	done:
	// cleanup
	if (ote_addr != NULL)
		KeReleaseSpinLock(&g_ot_hash_guard, irql);
	if (request.sid_a != NULL)
		free(request.sid_a);
	
	if (result == FILTER_ALLOW)
		{
		
		return ((PTDI_IND_RECEIVE_DATAGRAM)(ctx->old_handler))
		(ctx->old_context, SourceAddressLength, SourceAddress, OptionsLength,
		 Options, ReceiveDatagramFlags, BytesIndicated, BytesAvailable, BytesTaken,
		 Tsdu, IoRequestPacket);
		
		}
	else
		return STATUS_DATA_NOT_ACCEPTED;
}