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<hr><p align="left"><small>发信人: nothing (迷茫~浮), 信区: Winsock <br>
标 题: icq protocol(7) <br>
发信站: 武汉白云黄鹤站 (Thu May 11 10:18:46 2000), 转信 <br>
<br>
COMMUNICATION BETWEEN TWO CLIENTS USING TCP (Peer to peer mode) <br>
=============================================================== <br>
When a user wishes to send a message, an URL etc, to another user (called <br>
the "remote" user as opposite to the "local" user), the local user first <br>
checks to see if a TCP connection already is established to that user. If <br>
so is the case, then that connection will be used. If not, the user checks <br>
the remote users IP address and port number (information sent to the user <br>
from the server when the remote user logged in), and makes a connection to <br>
that address. Typical port numbers are in the range 1200-1300 (decimal). <br>
When a new connection is formed, a CHANNEL_INIT message must be sent. From <br>
there on, however, every time the user wishes to send a message, a <br>
CHANNEL_MESSAGE is sent. All messages sent must be acknowledged by the other <br>
side, using CHANNEL_ACK. Furthermore, all messages is replied to by another <br>
message from the receiver - which most often is empty, unless the user has <br>
posted a Away/DND message, in case this will be sent as a reply. <br>
The TCP communication is similar to the UDP communication, in that all <br>
communication is done trough separate packets (often, but now always <br>
associated with individual TCP packets). Each packet must contain the <br>
packet's length (excluding the length count) as the first two bytes. Most <br>
messages contains the senders UIN as the next field. <br>
CHANNEL_INIT Initiate inter-user communication using TCP <br>
------------ <br>
Parameters: <br>
Length Content (if fixed) Name Description <br>
------ ------------------ ---- ----------- <br>
2 bytes 1A 00 LENGTH Length of this packet <br>
1 byte FF INIT_IDENT Identifies this packet as an i <br>
nitiation <br>
4 bytes 02 00 00 00 X1 *Unknown <br>
4 bytes 00 00 00 00 X2 *Unknown <br>
4 bytes xx xx xx xx MY_UIN The local user's UIN <br>
4 bytes xx xx xx xx MY_IP The user's IP address <br>
4 bytes xx xx xx xx MY_IP_REAL The user's actual IP address <br>
1 byte 04 X3 *Unknown <br>
4 bytes xx xx xx xx MY_PORT The user's TCP port for incomi <br>
ng messages <br>
Note that the port used for the "outgoing" connection is different from <br>
MY_PORT, the port other clients use to connect to this client. For the <br>
difference between MY_IP and MY_IP_REAL, see USER_ONLINE. <br>
CHANNEL_MESSAGE Send message to online user <br>
------------ <br>
------------ <br>
Parameters: <br>
Length Content (if fixed) Name Description <br>
------ ------------------ ---- ----------- <br>
2 bytes xx xx LENGTH Length of this packet <br>
4 bytes xx xx xx xx UIN The local user's UIN <br>
2 bytes 02 00 VERSION Identifies this as a ICQ packe <br>
t <br>
2 bytes EE 07 MSG_COMMAND The message type for CHANNEL_M <br>
ESSAGE <br>
2 bytes 00 00 X1 *Unknown <br>
4 bytes xx xx xx xx UIN_2 The local user's UIN <br>
2 bytes xx xx TYPE Message type <br>
2 bytes xx xx LENGTH Length of MESSAGE including NU <br>
LL <br>
variable MESSAGE The message to be sent, NULL t <br>
erminated <br>
4 bytes xx xx xx xx MY_IP_REAL The user's actual IP address <br>
4 bytes xx xx xx xx MY_IP The user's IP address <br>
4 bytes xx xx xx xx PORT The user's TCP port for incomi <br>
ng messages <br>
1 byte 04 X2 *Unknown <br>
2 bytes 00 00 X3 *Unknown <br>
2 bytes xx xx CMD_TYPE Identifies message as new mess <br>
age or reply <br>
4 bytes xx xx xx xx X4 *Unknown (checksum? sequence n <br>
umber?) <br>
The TYPE is the same as described in RECEIVE_MESSAGE. The difference between <br>
MY_IP and MY_IP_REAL is described in USER_ONLINE. The CMD_TYPE can have two <br>
possible values: <br>
10 00 = This is a new ('real', user initiated) message <br>
00 00 = This is an auto reply <br>
The auto reply is sent as an acknowledgement to all 'real' messages. They <br>
usually contains an empty message, but if the remote user is 'Away' or in <br>
DND mode, the reply will contain the Away/DND message. The X4 field is a <br>
bit tricky. It is always between 00 FF FF FF and FF FF FF FF, but the exact <br>
function of the field is unknown. <br>
<br>
-- <br>
※ 来源:．武汉白云黄鹤站 bbs.whnet.edu.cn．[FROM: 202.120.9.13] <br>
</small><hr>
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