Protocols/MSNP/MSNC/P2Pv2 Headers

MSNP Protocol

MSNC

Overview • MSNObject

Client Capabilities

P2P protocol

Transports • MSNSLP

Headers

P2Pv1 Binary headers

P2Pv2 Binary headers

Transfers

Display Pictures

Custom Emoticons

File Transfer

Overview

Introduction • Terms • Clients

Reference

Error List • Commands • Relying Party Suite • Spotlife

Services

XMPP • HTTP Gateway • Tabs • Activities

Documentation

Development Tools • MSNP Grid

Polygamy • URLs used by MSN

Documents

Protocol Versions

Version 21

Version 18

Version 16

Version 15

Version 14

Version 13

Version 12

Version 11

Version 9

Version 8

Version 2

MSNC

Introduction • P2P • Object Descriptor • Display Pictures • File Transfer

Scenarios

Microsoft Messenger for Mac

MSNP on WebTV (MSNTV)

P2Pv2 Binary Headers (from MSNP16)

When the client Alice logs in using MSNP18, and starts a session to another WLM 2009 client Bob (I believe Alice knows the client type of Bob by the GUID that is attached to the email in Bob's JOI command) then the file transfer binary header is substantially changed.

All data is Big Endian. The binary header size is dynamic - It can be between 8(0x08) and 252(0xfc). The new P2P protocol always has header and message part is optional. Ex: Ack packets haven't message part.

0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L|O|Len|Base ID|if L>8 then TLVs = read(L - 8) else skip  ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| if Len > 0 then Payload = (DH and D) else skip           ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

For all of them - (DWORD is a 32-bit, 4 byte, unsigned integer and QWORD is 64 bits, 8 bytes.)

1	BYTE	HL	Length of header.
2	BYTE	OP	Operation code. 0: None, 2: Ack, 3: Init session.
3	WORD	ML	Message length without header length. (but included the header's message length)
4	DWORD	BaseID	Initially random (?) To get the next one add the payload length.
TLVs	BYTE[HL-8]	TLV Data	TLV list consists of TLV-encoded pairs (type, length, value). A whole TLV list is padded with zeros to fit 4-byte boundary. TLVs: T=0x1(1) L=0xc(12): IPv6 address of sender/receiver. T=0x2(2) L=0x4(4): ACK identifier.
DH	DHL	Data Header	BYTE DHL: Data header length BYTE TFCombination: 0x1=First, 0x4=Msn object (display picture, emoticon etc), 0x6=File transfer WORD PackageNumber: Package number DWORD SessionID: Session Identifier BYTE[DHL-8] Data packets TLVs: if (DHL>8) then read bytes(DHL - 8). T=0x1(1) L=0x8(8): Data remaining.
D	ML-DHL	Data Packet	SLP messsage or data packet
F	DWORD	Footer	The footer.

Examples

First P2P message

H: 18 03 05 4e 13 63 d5 a0 01 0c 00 02 00 00 00 0e 76 2d 0f 01 00 00 00 00 DH: 08 01 00 00 00 00 00 00 D: SLPMessage

All type of header has the follow fields:

1	0x18	Length of header	24
2	0x03	Operation code	Initialize session.
3	0x05 0x4e	Size of message	1358 = 1350+8(0x08)
4	0x13 0x63 0xd5 0xa0	Base ID	The next Base ID += Size of message
TLVs	01 0c 00020000 000e762d 0f010000 (00 00)	TLV data	TLV = 24 - 8 = 16 bytes. T=01,L=12,V=00020000 000e762d 0f010000. (00 00 = Padded with zeros to fit 4-byte boundary.)
DH	08 01 00 00 00 00 00 00	Data Header	08=DataHeaderLength 01=TFCombination 00 00=PackageNumber 00 00 00 00 = Session ID No TLV because DataHeaderLength - 8 = 0.
D	SLP	SLP	SLP Message

An acknowledgement

H: 08 02 00 00 93 e7 20 56 DH: (no data) D: (no data) F: 00 00 00 00

1	0x08	Length of header	8
2	0x02	Operation code	Acknowledgement
3	0x00 0x00	Size of message	0
4	0x93 0xe7 0x20 0x56	Base ID	AckIdentifier = Base ID + Size of Message
TLVs	(No tlv data)	TLVs	Length of header <= 8, so no TLVs in this sample package.
DH	(no data)	Data Header	Size of message is 0.
D	(no data)	Data	Size of message is 0.
F	0x00 0x00 0x00 0x00	Footer	Footer is 0 (always).

File Transfer

H: 08 00 05 70 13 63 da ee DH: 14 07 00 00 d1 c5 26 da 01 08 00 00 00 00 00 02 04 1c 00 00 D: ...

1	0x08	Length of header	8
2	0x00	Operation code	None
3	0x05 0x70	Size of message	1392 = 1372+20(0x14)
4	0x13 0x63 0xda 0xee	Base ID	The next Base ID += Size of message
TLVs	(No tlv data)	TLVs	Length of header <= 8, so no TLVs in this sample package.
DH	14 07 0000 d1c526da 01 08 00000000 0002041c 0000	Data Header	0x14(20)=DataHeaderLength 0x07=TFCombination(The first file transfer message. 0x06 is all other file transfer message) 0x00 0x00=PackageNumber 0xd1 0xc5 0x26 0xda = Session ID from SLP TLVs = 20-8=12 bytes. T(01) L(08) V(00 00 00 00 00 02 04 1c - data remaining) Padding(00 00)
D	Data	Data	File data

Display Picture

H: 08 00 05 70 03 a3 da ee DH: 14 05 00 00 d1 c5 26 dc 01 08 00 00 00 00 00 00 34 f5 00 00 D: ...

1	0x08	Length of header	8
2	0x00	Operation code	None
3	0x05 0x70	Size of message	1392 = 1372+20(0x14)
4	0x03 0xa3 0xda 0xee	Base ID	The next Base ID += Size of message
TLVs	(No tlv data)	TLVs	Length of header <= 8, so no TLVs in this sample package.
DH	14 05 0000 d1c526da 01 08 00000000 000034f5 0000	Data Header	0x14(20)=DataHeaderLength 0x5=TFCombination(The first display picture message. 0x04 is all other display picture message) 0x0 0x0=PackageNumber 0xd1 0xc5 0x26 0xda = Session ID from SLP TLVs = 20-8=12 bytes. T(01) L(08) V(00 00 00 00 00 00 34 f5 - data remaining) Padding(00 00)
D	Data	Data	Picture data

For more information

P2Pv1 and P2Pv2 Header Definitions

Binary header research on MSNC10 (The new P2P protocol used in WLM 2009 and MSNP18)