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/****************************************************************************
* ip_conntrack_h323_asn1.h - BER and PER decoding library for H.323
* conntrack/NAT module.
*
* Copyright (c) 2006 by Jing Min Zhao <zhaojingmin@users.sourceforge.net>
*
* This source code is licensed under General Public License version 2.
*
*
* This library is based on H.225 version 4, H.235 version 2 and H.245
* version 7. It is extremely optimized to decode only the absolutely
* necessary objects in a signal for Linux kernel NAT module use, so don't
* expect it to be a full ASN.1 library.
*
* Features:
*
* 1. Small. The total size of code plus data is less than 20 KB (IA32).
* 2. Fast. Decoding Netmeeting's Setup signal 1 million times on a PIII 866
* takes only 3.9 seconds.
* 3. No memory allocation. It uses a static object. No need to initialize or
* cleanup.
* 4. Thread safe.
* 5. Support embedded architectures that has no misaligned memory access
* support.
*
* Limitations:
*
* 1. At most 30 faststart entries. Actually this is limited by ethernet's MTU.
* If a Setup signal contains more than 30 faststart, the packet size will
* very likely exceed the MTU size, then the TPKT will be fragmented. I
* don't know how to handle this in a Netfilter module. Anybody can help?
* Although I think 30 is enough for most of the cases.
* 2. IPv4 addresses only.
*
****************************************************************************/
#ifndef _NF_CONNTRACK_HELPER_H323_ASN1_H_
#define _NF_CONNTRACK_HELPER_H323_ASN1_H_
/*****************************************************************************
* H.323 Types
****************************************************************************/
#include "nf_conntrack_h323_types.h"
typedef struct {
enum {
Q931_NationalEscape = 0x00,
Q931_Alerting = 0x01,
Q931_CallProceeding = 0x02,
Q931_Connect = 0x07,
Q931_ConnectAck = 0x0F,
Q931_Progress = 0x03,
Q931_Setup = 0x05,
Q931_SetupAck = 0x0D,
Q931_Resume = 0x26,
Q931_ResumeAck = 0x2E,
Q931_ResumeReject = 0x22,
Q931_Suspend = 0x25,
Q931_SuspendAck = 0x2D,
Q931_SuspendReject = 0x21,
Q931_UserInformation = 0x20,
Q931_Disconnect = 0x45,
Q931_Release = 0x4D,
Q931_ReleaseComplete = 0x5A,
Q931_Restart = 0x46,
Q931_RestartAck = 0x4E,
Q931_Segment = 0x60,
Q931_CongestionCtrl = 0x79,
Q931_Information = 0x7B,
Q931_Notify = 0x6E,
Q931_Status = 0x7D,
Q931_StatusEnquiry = 0x75,
Q931_Facility = 0x62
} MessageType;
H323_UserInformation UUIE;
} Q931;
/*****************************************************************************
* Decode Functions Return Codes
****************************************************************************/
#define H323_ERROR_NONE 0 /* Decoded successfully */
#define H323_ERROR_STOP 1 /* Decoding stopped, not really an error */
#define H323_ERROR_BOUND -1
#define H323_ERROR_RANGE -2
/*****************************************************************************
* Decode Functions
****************************************************************************/
int DecodeRasMessage(unsigned char *buf, size_t sz, RasMessage * ras);
int DecodeQ931(unsigned char *buf, size_t sz, Q931 * q931);
int DecodeMultimediaSystemControlMessage(unsigned char *buf, size_t sz,
MultimediaSystemControlMessage *
mscm);
#endif