1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /****************************************************************************
3 * BER and PER decoding library for H.323 conntrack/NAT module.
4 *
5 * Copyright (c) 2006 by Jing Min Zhao <zhaojingmin@users.sourceforge.net>
6 *
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.
11 *
12 * Features:
13 *
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
18 * cleanup.
19 * 4. Thread safe.
20 * 5. Support embedded architectures that has no misaligned memory access
21 * support.
22 *
23 * Limitations:
24 *
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.
31 *
32 ****************************************************************************/
33
34 #ifndef _NF_CONNTRACK_HELPER_H323_ASN1_H_
35 #define _NF_CONNTRACK_HELPER_H323_ASN1_H_
36
37 /*****************************************************************************
38 * H.323 Types
39 ****************************************************************************/
40
41 #include <linux/types.h>
42 #include <linux/netfilter/nf_conntrack_h323_types.h>
43
44 typedef struct {
45 enum {
46 Q931_NationalEscape = 0x00,
47 Q931_Alerting = 0x01,
48 Q931_CallProceeding = 0x02,
49 Q931_Connect = 0x07,
50 Q931_ConnectAck = 0x0F,
51 Q931_Progress = 0x03,
52 Q931_Setup = 0x05,
53 Q931_SetupAck = 0x0D,
54 Q931_Resume = 0x26,
55 Q931_ResumeAck = 0x2E,
56 Q931_ResumeReject = 0x22,
57 Q931_Suspend = 0x25,
58 Q931_SuspendAck = 0x2D,
59 Q931_SuspendReject = 0x21,
60 Q931_UserInformation = 0x20,
61 Q931_Disconnect = 0x45,
62 Q931_Release = 0x4D,
63 Q931_ReleaseComplete = 0x5A,
64 Q931_Restart = 0x46,
65 Q931_RestartAck = 0x4E,
66 Q931_Segment = 0x60,
67 Q931_CongestionCtrl = 0x79,
68 Q931_Information = 0x7B,
69 Q931_Notify = 0x6E,
70 Q931_Status = 0x7D,
71 Q931_StatusEnquiry = 0x75,
72 Q931_Facility = 0x62
73 } MessageType;
74 H323_UserInformation UUIE;
75 } Q931;
76
77 /*****************************************************************************
78 * Decode Functions Return Codes
79 ****************************************************************************/
80
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
85
86
87 /*****************************************************************************
88 * Decode Functions
89 ****************************************************************************/
90
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 *
95 mscm);
96
97 #endif