1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /****************************************************************************
3 * BER and PER decoding library for H.323 conntrack/NAT module.
5 * Copyright (c) 2006 by Jing Min Zhao <zhaojingmin@users.sourceforge.net>
7 * This library is based on H.225 version 4, H.235 version 2 and H.245
8 * version 7. It is extremely optimized to decode only the absolutely
9 * necessary objects in a signal for Linux kernel NAT module use, so don't
10 * expect it to be a full ASN.1 library.
14 * 1. Small. The total size of code plus data is less than 20 KB (IA32).
15 * 2. Fast. Decoding Netmeeting's Setup signal 1 million times on a PIII 866
16 * takes only 3.9 seconds.
17 * 3. No memory allocation. It uses a static object. No need to initialize or
20 * 5. Support embedded architectures that has no misaligned memory access
25 * 1. At most 30 faststart entries. Actually this is limited by ethernet's MTU.
26 * If a Setup signal contains more than 30 faststart, the packet size will
27 * very likely exceed the MTU size, then the TPKT will be fragmented. I
28 * don't know how to handle this in a Netfilter module. Anybody can help?
29 * Although I think 30 is enough for most of the cases.
30 * 2. IPv4 addresses only.
32 ****************************************************************************/
34 #ifndef _NF_CONNTRACK_HELPER_H323_ASN1_H_
35 #define _NF_CONNTRACK_HELPER_H323_ASN1_H_
37 /*****************************************************************************
39 ****************************************************************************/
41 #include <linux/types.h>
42 #include <linux/netfilter/nf_conntrack_h323_types.h>
46 Q931_NationalEscape = 0x00,
48 Q931_CallProceeding = 0x02,
50 Q931_ConnectAck = 0x0F,
55 Q931_ResumeAck = 0x2E,
56 Q931_ResumeReject = 0x22,
58 Q931_SuspendAck = 0x2D,
59 Q931_SuspendReject = 0x21,
60 Q931_UserInformation = 0x20,
61 Q931_Disconnect = 0x45,
63 Q931_ReleaseComplete = 0x5A,
65 Q931_RestartAck = 0x4E,
67 Q931_CongestionCtrl = 0x79,
68 Q931_Information = 0x7B,
71 Q931_StatusEnquiry = 0x75,
74 H323_UserInformation UUIE;
77 /*****************************************************************************
78 * Decode Functions Return Codes
79 ****************************************************************************/
81 #define H323_ERROR_NONE 0 /* Decoded successfully */
82 #define H323_ERROR_STOP 1 /* Decoding stopped, not really an error */
83 #define H323_ERROR_BOUND -1
84 #define H323_ERROR_RANGE -2
87 /*****************************************************************************
89 ****************************************************************************/
91 int DecodeRasMessage(unsigned char *buf, size_t sz, RasMessage * ras);
92 int DecodeQ931(unsigned char *buf, size_t sz, Q931 * q931);
93 int DecodeMultimediaSystemControlMessage(unsigned char *buf, size_t sz,
94 MultimediaSystemControlMessage *