include/linux/netfilter/nf_conntrack_h323_asn1.h

   1 /****************************************************************************
   2  * ip_conntrack_h323_asn1.h - BER and PER decoding library for H.323
   3  *                            conntrack/NAT module.
   4  *
   5  * Copyright (c) 2006 by Jing Min Zhao <zhaojingmin@users.sourceforge.net>
   6  *
   7  * This source code is licensed under General Public License version 2.
   8  *
   9  *
  10  * This library is based on H.225 version 4, H.235 version 2 and H.245
  11  * version 7. It is extremely optimized to decode only the absolutely
  12  * necessary objects in a signal for Linux kernel NAT module use, so don't
  13  * expect it to be a full ASN.1 library.
  14  *
  15  * Features:
  16  *
  17  * 1. Small. The total size of code plus data is less than 20 KB (IA32).
  18  * 2. Fast. Decoding Netmeeting's Setup signal 1 million times on a PIII 866
  19  *    takes only 3.9 seconds.
  20  * 3. No memory allocation. It uses a static object. No need to initialize or
  21  *    cleanup.
  22  * 4. Thread safe.
  23  * 5. Support embedded architectures that has no misaligned memory access
  24  *    support.
  25  *
  26  * Limitations:
  27  *
  28  * 1. At most 30 faststart entries. Actually this is limited by ethernet's MTU.
  29  *    If a Setup signal contains more than 30 faststart, the packet size will
  30  *    very likely exceed the MTU size, then the TPKT will be fragmented. I
  31  *    don't know how to handle this in a Netfilter module. Anybody can help?
  32  *    Although I think 30 is enough for most of the cases.
  33  * 2. IPv4 addresses only.
  34  *
  35  ****************************************************************************/
  36
  37 #ifndef _NF_CONNTRACK_HELPER_H323_ASN1_H_
  38 #define _NF_CONNTRACK_HELPER_H323_ASN1_H_
  39
  40 /*****************************************************************************
  41  * H.323 Types
  42  ****************************************************************************/
  43 #include "nf_conntrack_h323_types.h"
  44
  45 typedef struct {
  46         enum {
  47                 Q931_NationalEscape = 0x00,
  48                 Q931_Alerting = 0x01,
  49                 Q931_CallProceeding = 0x02,
  50                 Q931_Connect = 0x07,
  51                 Q931_ConnectAck = 0x0F,
  52                 Q931_Progress = 0x03,
  53                 Q931_Setup = 0x05,
  54                 Q931_SetupAck = 0x0D,
  55                 Q931_Resume = 0x26,
  56                 Q931_ResumeAck = 0x2E,
  57                 Q931_ResumeReject = 0x22,
  58                 Q931_Suspend = 0x25,
  59                 Q931_SuspendAck = 0x2D,
  60                 Q931_SuspendReject = 0x21,
  61                 Q931_UserInformation = 0x20,
  62                 Q931_Disconnect = 0x45,
  63                 Q931_Release = 0x4D,
  64                 Q931_ReleaseComplete = 0x5A,
  65                 Q931_Restart = 0x46,
  66                 Q931_RestartAck = 0x4E,
  67                 Q931_Segment = 0x60,
  68                 Q931_CongestionCtrl = 0x79,
  69                 Q931_Information = 0x7B,
  70                 Q931_Notify = 0x6E,
  71                 Q931_Status = 0x7D,
  72                 Q931_StatusEnquiry = 0x75,
  73                 Q931_Facility = 0x62
  74         } MessageType;
  75         H323_UserInformation UUIE;
  76 } Q931;
  77
  78 /*****************************************************************************
  79  * Decode Functions Return Codes
  80  ****************************************************************************/
  81
  82 #define H323_ERROR_NONE 0       /* Decoded successfully */
  83 #define H323_ERROR_STOP 1       /* Decoding stopped, not really an error */
  84 #define H323_ERROR_BOUND -1
  85 #define H323_ERROR_RANGE -2
  86
  87
  88 /*****************************************************************************
  89  * Decode Functions
  90  ****************************************************************************/
  91
  92 int DecodeRasMessage(unsigned char *buf, size_t sz, RasMessage * ras);
  93 int DecodeQ931(unsigned char *buf, size_t sz, Q931 * q931);
  94 int DecodeMultimediaSystemControlMessage(unsigned char *buf, size_t sz,
  95                                          MultimediaSystemControlMessage *
  96                                          mscm);
  97
  98 #endif