Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 1 | /**************************************************************************** |
| 2 | * ip_conntrack_helper_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@hotmail.com> |
| 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 _IP_CONNTRACK_HELPER_H323_ASN1_H_ |
| 38 | #define _IP_CONNTRACK_HELPER_H323_ASN1_H_ |
| 39 | |
| 40 | /***************************************************************************** |
| 41 | * H.323 Types |
| 42 | ****************************************************************************/ |
| 43 | #include "ip_conntrack_helper_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 |