📄 256.htm
字号:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>CTerm非常精华下载</title>
</head>
<body bgcolor="#FFFFFF">
<table border="0" width="100%" cellspacing="0" cellpadding="0" height="577">
<tr><td width="32%" rowspan="3" height="123"><img src="DDl_back.jpg" width="300" height="129" alt="DDl_back.jpg"></td><td width="30%" background="DDl_back2.jpg" height="35"><p align="center"><a href="http://apue.dhs.org"><font face="黑体"><big><big>apue</big></big></font></a></td></tr>
<tr>
<td width="68%" background="DDl_back2.jpg" height="44"><big><big><font face="黑体"><p align="center"> ● UNIX网络编程 (BM: clown) </font></big></big></td></tr>
<tr>
<td width="68%" height="44" bgcolor="#000000"><font face="黑体"><big><big><p align="center"></big></big><a href="http://cterm.163.net"><img src="banner.gif" width="400" height="60" alt="banner.gif"border="0"></a></font></td>
</tr>
<tr><td width="100%" colspan="2" height="100" align="center" valign="top"><br><p align="center">[<a href="index.htm">回到开始</a>][<a href="247.htm">上一层</a>][<a href="257.htm">下一篇</a>]
<hr><p align="left"><small>发信人: nothing (迷茫~浮), 信区: Winsock <br>
标 题: icq protocl(2) <br>
发信站: 武汉白云黄鹤站 (Thu May 11 10:14:36 2000), 转信 <br>
<br>
Introduction <br>
------------ <br>
Communication with persons online is done through a direct TCP connection <br>
to that person. All other communication is done through UDP packets sent to <br>
the ICQ server. All UDP packets must be acknowledged by the receiver. <br>
Retransmission will occur in 10 seconds if a acknowledgement is not <br>
received. After 6 unsuccessfull transmissions, a B_MESSAGE_ACK message will <br>
be sent. The whole procedure is repeated 2 times. If there is still no <br>
reply, the ICQ client will assume the user to be disconneced. <br>
Before any communication between users can take place, the client must <br>
register at the server by logging in. During the login process, the client <br>
sends information about itself to the server, including its IP address, the <br>
TCP port reserved for ICQ, the user's password and the user's contact list. <br>
>From now on, the client will assume itself to be 'connected', and will every <br>
now and then send a 'keep alive' message to the server. This keep alive <br>
message performs two functions: it makes the client sure that it still has <br>
access to the server, and it makes the server sure that the user is still <br>
online. By default, the client will 'connect' to the server on UDP port 4000. <br>
Functions such as sending messages to offline users, getting information <br>
about a user, searching for users in the ICQ Global Directory and changing <br>
password is done by sending UDP packets to the ICQ server. These packets do <br>
all follow a simple template, including the senders UIN, a special code <br>
indicating which function the server should perform, and optional <br>
parameters. <br>
When a user sends a message/URL/etc to another user that is currently <br>
connected, the ICQ client will establish a TCP connection directly to that <br>
user, and send the message using a format similar (but not identical) to the <br>
format used by the UDP packet messaging. After the message has been sent, <br>
the TCP connection is not closed, but instead kept open and used for future <br>
messages to that user. The connection is closed when either of the two users <br>
disconnect from their ICQ connection. <br>
Please note that throughout this document, all numbers are in hexadecimal <br>
unless stated otherwise. Integers consisting of more than one byte is stored <br>
with the least significant byte first, and the most significant byte last <br>
(as is usual on the PC/Intel architecture). All text strings etc are <br>
preceded by a two byte long LENGTH field, indicating the length of the <br>
string. All strings are also NULL terminated, i.e. followed by the byte with <br>
the value 00. When reading packets, either information may be used to <br>
determine the length of the string, but when sending both must be present. <br>
All strings are coded as usual MS Windows texts, i.e. in ISO Latin-1 <br>
charset, and lines terminated by CR/LF. (Not all strings may contain line <br>
breaks. This should be clear from context.) <br>
<br>
-- <br>
※ 来源:．武汉白云黄鹤站 bbs.whnet.edu.cn．[FROM: 202.120.9.13] <br>
</small><hr>
<p align="center">[<a href="index.htm">回到开始</a>][<a href="247.htm">上一层</a>][<a href="257.htm">下一篇</a>]
<p align="center"><a href="http://cterm.163.net">欢迎访问Cterm主页</a></p>
</table>
</body>
</html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -