📄 dos下的网络编程.mht
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style=3D'mso-spacerun:yes'> </span>//</span><span style=3D'font-size:=
12.0pt;
line-height:125%;font-family:NSimSun'>地址格式<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><span
style=3D'mso-spacerun:yes'> </span><span
style=3D'mso-spacerun:yes'> </span>unsigned short sin_port;<span
style=3D'mso-spacerun:yes'> </span>//</span><span
style=3D'font-size:12.0pt;line-height:125%;font-family:NSimSun'>端=
1475;号<span
lang=3DEN-US>(</span>使用网络字节༿=
4;序<span
lang=3DEN-US>)<o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><span
style=3D'mso-spacerun:yes'> </span><span
style=3D'mso-spacerun:yes'> </span>struct in_addr sin_addr;<span
style=3D'mso-spacerun:yes'> </span>//IP</span><span
style=3D'font-size:12.0pt;line-height:125%;font-family:NSimSun'>地=
2336;<span
lang=3DEN-US>(</span>使用网络字节༿=
4;序<span
lang=3DEN-US>)<o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><span
style=3D'mso-spacerun:yes'> </span><span
style=3D'mso-spacerun:yes'> </span>char <span
style=3D'mso-spacerun:yes'> =
</span>sin_zero[8];
//</span><span style=3D'font-size:12.0pt;line-height:125%;font-family:NSimS=
un'>空字节<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>};<o:p></o:p></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span style=3D'font-size:12=
.0pt;
line-height:125%;font-family:NSimSun'>结构中的<span
lang=3DEN-US>sin_family</span>字段用来指ê=
50;地址格式，在不同的=
操作系统下，取值可=
0197;指定为<span
lang=3DEN-US>AF_UNSPEC</span>，<span lang=3DEN-US>AF_UNIX</span>û=
10;<span
lang=3DEN-US>AF_OSI</span>等不同的值，&=
#20294;是在这里我们只能=
351;用<span
lang=3DEN-US>AF_INET</span>。<span lang=3DEN-US><o:p></o:p></span></s=
pan></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><o:p> </o:p></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>sin_addr</span><span
style=3D'font-size:12.0pt;line-height:125%;font-family:NSimSun'>字=
7573;是个<span
lang=3DEN-US>in_addr</span>结构，这个结=
构实际上就是<span
lang=3DEN-US>4</span>个字节。<span lang=3DEN-US><o:=
p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><o:p> </o:p></span></p>
<h3 style=3D'line-height:125%'><span lang=3DEN-US style=3D'font-family:NSim=
Sun'>3 </span><span
style=3D'font-family:NSimSun'>网络字节顺ò=
07;<span
lang=3DEN-US><o:p></o:p></span></span></h3>
<p class=3DMsoNormal style=3D'line-height:125%'><span style=3D'font-size:12=
.0pt;
line-height:125%;font-family:NSimSun'>不同的处ĩ=
02;器对字节顺序的处理=
方式不同，有的是高=
0301;在前，有的是低位ࢷ=
2;前。<span
lang=3DEN-US>TCP/IP</span>协议统一规定&=
#20351;用高位在前的方式=
256;输数据，很遗憾，这=
;与<span
lang=3DEN-US>Intel80x86</span>系列处理器Ë=
51;用的方式不同，所以=
在<span
lang=3DEN-US>80x86</span>平台下的<span lang=3DEN-US=
>socket</span>编程中，当需要ß=
12;协议中使用参数时，=
必须首先将它们转换=
0026;<span
lang=3DEN-US>Internet</span>顺序。<span lang=3DEN-US><o:p=
></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><o:p> </o:p></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span style=3D'font-size:12=
.0pt;
line-height:125%;font-family:NSimSun'>在填写<span lang=3D=
EN-US>sockaddr_in</span>结构的<span
lang=3DEN-US>sin_port</span>字段和<span lang=3DEN-US>sin_=
addr</span>字段时，必须首先=
进行转换。下面就是=
9968;些字节转换函数：<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>16</span><span style=3D'font-s=
ize:
12.0pt;line-height:125%;font-family:NSimSun'>位：<span lang=3DE=
N-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>unsigned shorthtons(unsigned s=
hort);
//</span><span style=3D'font-size:12.0pt;line-height:125%;font-family:NSimS=
un'>主机顺序</span><span
lang=3DEN-US style=3D'font-size:12.0pt;line-height:125%;font-family:Wingdin=
gs;
mso-ascii-font-family:NSimSun;mso-fareast-font-family:NSimSun;mso-hansi-fon=
t-family:
NSimSun;mso-char-type:symbol;mso-symbol-font-family:Wingdings'><span
style=3D'mso-char-type:symbol;mso-symbol-font-family:Wingdings'>à</s=
pan></span><span
style=3D'font-size:12.0pt;line-height:125%;font-family:NSimSun'>网=
2476;顺序<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>unsigned shortntohs(unsigned
short); //</span><span style=3D'font-size:12.0pt;line-height:125%;font-fami=
ly:
NSimSun'>网络顺序</span><span lang=3DEN-US
style=3D'font-size:12.0pt;line-height:125%;font-family:Wingdings;mso-ascii-=
font-family:
NSimSun;mso-fareast-font-family:NSimSun;mso-hansi-font-family:NSimSun;
mso-char-type:symbol;mso-symbol-font-family:Wingdings'><span style=3D'mso-c=
har-type:
symbol;mso-symbol-font-family:Wingdings'>à</span></span><span
style=3D'font-size:12.0pt;line-height:125%;font-family:NSimSun'>主=
6426;顺序<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>32</span><span style=3D'font-s=
ize:
12.0pt;line-height:125%;font-family:NSimSun'>位：<span lang=3DE=
N-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>unsigned long htonl(unsigned l=
ong);
//</span><span style=3D'font-size:12.0pt;line-height:125%;font-family:NSimS=
un'>主机顺序</span><span
lang=3DEN-US style=3D'font-size:12.0pt;line-height:125%;font-family:Wingdin=
gs;
mso-ascii-font-family:NSimSun;mso-fareast-font-family:NSimSun;mso-hansi-fon=
t-family:
NSimSun;mso-char-type:symbol;mso-symbol-font-family:Wingdings'><span
style=3D'mso-char-type:symbol;mso-symbol-font-family:Wingdings'>à</s=
pan></span><span
style=3D'font-size:12.0pt;line-height:125%;font-family:NSimSun'>网=
2476;顺序<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>unsigned long ntohl(unsigned l=
ong);
//</span><span style=3D'font-size:12.0pt;line-height:125%;font-family:NSimS=
un'>网络顺序</span><span
lang=3DEN-US style=3D'font-size:12.0pt;line-height:125%;font-family:Wingdin=
gs;
mso-ascii-font-family:NSimSun;mso-fareast-font-family:NSimSun;mso-hansi-fon=
t-family:
NSimSun;mso-char-type:symbol;mso-symbol-font-family:Wingdings'><span
style=3D'mso-char-type:symbol;mso-symbol-font-family:Wingdings'>à</s=
pan></span><span
style=3D'font-size:12.0pt;line-height:125%;font-family:NSimSun'>主=
6426;顺序<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><o:p> </o:p></span></p>
<h3 style=3D'line-height:125%'><span lang=3DEN-US style=3D'font-family:NSim=
Sun'>4 IP</span><span
style=3D'font-family:NSimSun'>地址转换函ă=
68;<span
lang=3DEN-US><o:p></o:p></span></span></h3>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>unsigned long inet_addr(char f=
ar
*);<o:p></o:p></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span style=3D'font-size:12=
.0pt;
line-height:125%;font-family:NSimSun'>将“<span lang=3DEN-US>aa.=
bb.cc.dd</span>”类型的十进制é=
83;符串转换成<span
lang=3DEN-US>32</span>位的<span lang=3DEN-US>IP</span>地&=
#22336;。如果失败，返回<span
lang=3DEN-US>INADDR_NONE</span>。<span lang=3DEN-US><o:p></o:p></span=
></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><o:p> </o:p></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'>char far * inet_ntoa(struct
in_addr);<o:p></o:p></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span style=3D'font-size:12=
.0pt;
line-height:125%;font-family:NSimSun'>将网络字Ŏ=
10;顺序的<span
lang=3DEN-US>32</span>位<span lang=3DEN-US>IP</span>地址&=
#36716;换成字符串。返回=
968;个指针，指向转换后=
;的<span
lang=3DEN-US>IP</span>地址字符串，Ű=
25;个字符串位于<span
lang=3DEN-US>socket</span>接口的内部缓&=
#20914;区，所以，在调用<span
lang=3DEN-US>inet_ntoa</span>后必须马上৚=
6;字符串拷贝到自己定&=
#20041;的缓冲区中。<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><o:p> </o:p></span></p>
<h3 style=3D'line-height:125%'><span lang=3DEN-US style=3D'font-family:NSim=
Sun'>5 </span><span
style=3D'font-family:NSimSun'>套接字<span lang=3DEN-US><o=
:p></o:p></span></span></h3>
<p class=3DMsoNormal style=3D'line-height:125%'><span style=3D'font-size:12=
.0pt;
line-height:125%;font-family:NSimSun'>两个主机È=
43;间进行网络传输，首=
先必须建立一个用来=
6890;信的对象，这个对ฉ=
7;就称为套接字<span
lang=3DEN-US>(socket)</span>，套接字的定=
;义是“通信的一端”A=
292;在通信的另一端必定=
;有另一个套接字与之&#=
30456;对应，以便互相传Ű=
82;数据。仅从编程的角=
度来看，套接字就是=
9968;个整数标识符而已ᦁ=
2;但使用<span
lang=3DEN-US>socket</span>这个称呼好像&=
#26356;贴切。<span
lang=3DEN-US><o:p></o:p></span></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span lang=3DEN-US style=3D=
'font-size:
12.0pt;line-height:125%;font-family:NSimSun'><o:p> </o:p></span></p>
<p class=3DMsoNormal style=3D'line-height:125%'><span style=3D'font-size:12=
.0pt;
line-height:125%;font-family:NSimSun'>套接字的ķ=
81;类有很多种，最主要=
的是流套接字<span
lang=3DEN-US>(stream socket)</span>和数据报套=
接字<span
lang=3DEN-US>(datagram socket)</span>。由于流࣯=
1;接字使用传输层的<span
lang=3DEN-US>TCP</span>协议进行通信A=
292;所以它具有<span
lang=3DEN-US>TCP</span>协议所拥有的=
508;种特征，比如：它是=
;面向连接的、稳定的&#=
65292;以及数据包是按顺ò=
07;发送的；而数据包套=
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