Linux Socket编程实例(一个Hello World程序)

/**/

/*
*

?*?Tcp?Server?program,?It?is?a?simple?example?only.

?*?zhengsh?200520602061?2

?*?when?client?connect?to?server,?send?a?welcome?message?and?timestamp?in?server.

?
*/







?

#include?
<
stdio.h
>






#include?
<
sys
/
socket.h
>






#include?
<
unistd.h
>






#include?
<
sys
/
types.h
>






#include?
<
netinet
/
in
.h
>






#include?
<
stdlib.h
>






#include?
<
time.h
>






?


#define
?SERVER_PORT?20000?
//
?define?the?defualt?connect?port?id








#define
?LENGTH_OF_LISTEN_QUEUE?10?
//
length?of?listen?queue?in?server








#define
?BUFFER_SIZE?255








#define
?WELCOME_MESSAGE?"welcome?to?connect?the?server.?"






?

?


int
?main(
int
?argc,?
char
?
**
argv)






{

???????
int
?servfd,clifd;

???????
struct
?sockaddr_in?servaddr,cliaddr;

?

???????
if
?((servfd?
=
?socket(AF_INET,SOCK_STREAM,
0
))?
<
?
0
)

???????




{

??????????????printf(
"
create?socket?error!\n
"
);

??????????????exit(
1
);

???????}







???????bzero(
&
servaddr,
sizeof
(servaddr));

???????servaddr.sin_family?
=
?AF_INET;

???????servaddr.sin_port?
=
?htons(SERVER_PORT);

???????servaddr.sin_addr.s_addr?
=
?htons(INADDR_ANY);

?

???????
if
?(bind(servfd,(
struct
?sockaddr
*
)
&
servaddr,
sizeof
(servaddr))
<
0
)

???????




{

??????????????printf(
"
bind?to?port?%d?failure!\n
"
,SERVER_PORT);

??????????????exit(
1
);

???????}







?

???????
if
?(listen(servfd,LENGTH_OF_LISTEN_QUEUE)?
<
?
0
)

???????




{

??????????????printf(
"
call?listen?failure!\n
"
);

??????????????exit(
1
);

???????}







?

???????
while
?(
1
)

???????




{
//
server?loop?will?nerver?exit?unless?any?body?kill?the?process








??????????????
char
?buf[BUFFER_SIZE];

??????????????
long
?timestamp;

??????????????socklen_t?length?
=
?
sizeof
(cliaddr);

??????????????clifd?
=
?accept(servfd,(
struct
?sockaddr
*
)
&
cliaddr,
&
length);

??????????????
if
?(clifd?
<
?
0
)

??????????????




{

?????????????????????printf(
"
error?comes?when?call?accept!\n
"
);

?????????????????????
break
;

??????????????}







??????????????strcpy(buf,WELCOME_MESSAGE);

??????????????
//
inet_ntop(INET_ADDRSTRLEN,cliaddr.sin_addr,buf,BUFFER_SIZE);








??????????????

??????????????printf(
"
from?client,IP:%s,Port:%d\n
"
,inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.sin_port));

??????????????timestamp?
=
?time(NULL);

??????????????strcat(buf,
"
timestamp?in?server:
"
);

??????????????strcat(buf,ctime(
&
timestamp));

??????????????send(clifd,buf,BUFFER_SIZE,
0
);

??????????????close(clifd);???????????

??????????????

???????}

//
exit








???????close(servfd);

???????
return
?
0
;

}







?

?客户每次用一个随机的端口连接服务器,并接收来自服务器的欢迎信息

,然后打印出来(tcpclient).运行的时候接受一个参数,也就是服务器的ip地址.



/**/

/*
?Tcp?client?program,?It?is?a?simple?example?only.

?*?zhengsh?200520602061?2

?*?connect?to?server,?and?echo?a?message?from?server.

?
*/







?

?

#include?
<
stdio.h
>






#include?
<
sys
/
socket.h
>






#include?
<
unistd.h
>






#include?
<
sys
/
types.h
>






#include?
<
netinet
/
in
.h
>






#include?
<
stdlib.h
>






?


#define
?SERVER_PORT?20000?
//
?define?the?defualt?connect?port?id








#define
?CLIENT_PORT?((20001+rand())%65536)?
//
?define?the?defualt?client?port?as?a?random?port






?


#define
?BUFFER_SIZE?255








#define
?REUQEST_MESSAGE?"welcome?to?connect?the?server.\n"






?


void
?usage(
char
?
*
name)






{

???????printf(
"
usage:?%s?IpAddr\n
"
,name);

}







?


int
?main(
int
?argc,?
char
?
**
argv)






{?????

???????
int
?servfd,clifd,length?
=
?
0
;

???????
struct
?sockaddr_in?servaddr,cliaddr;

???????socklen_t?socklen?
=
?
sizeof
(servaddr);

???????
char
?buf[BUFFER_SIZE];

???????

???????
if
?(argc?
<
?
2
)

???????




{

??????????????usage(argv[
0
]);

??????????????exit(
1
);

???????}







???????

???????
if
?((clifd?
=
?socket(AF_INET,SOCK_STREAM,
0
))?
<
?
0
)

???????




{

??????????????printf(
"
create?socket?error!\n
"
);

??????????????exit(
1
);

???????}







???????srand(time(NULL));
//
initialize?random?generator








???????bzero(
&
cliaddr,
sizeof
(cliaddr));

???????cliaddr.sin_family?
=
?AF_INET;

???????cliaddr.sin_port?
=
?htons(CLIENT_PORT);

???????cliaddr.sin_addr.s_addr?
=
?htons(INADDR_ANY);

?

???????bzero(
&
servaddr,
sizeof
(servaddr));

???????servaddr.sin_family?
=
?AF_INET;

???????inet_aton(argv[
1
],
&
servaddr.sin_addr);

???????servaddr.sin_port?
=
?htons(SERVER_PORT);

???????
//
servaddr.sin_addr.s_addr?=?htons(INADDR_ANY);








?

???????
if
?(bind(clifd,(
struct
?sockaddr
*
)
&
cliaddr,
sizeof
(cliaddr))
<
0
)

???????




{

??????????????printf(
"
bind?to?port?%d?failure!\n
"
,CLIENT_PORT);

??????????????exit(
1
);

???????}







?

???????
if
?(connect(clifd,(
struct
?sockaddr
*
)
&
servaddr,?socklen)?
<
?
0
)

???????




{

??????????????printf(
"
can't?connect?to?%s!\n
"
,argv[
1
]);

??????????????exit(
1
);

???????}







???????

???????length?
=
?recv(clifd,buf,BUFFER_SIZE,
0
);

???????
if
?(length?
<
?
0
)

???????




{

??????????????printf(
"
error?comes?when?recieve?data?from?server?%s!
"
,argv[
1
]);

??????????????exit(
1
);

???????}







???????printf(
"
from?server?%s?:\n\t%s?
"
,argv[
1
],buf);

?

???????close(clifd);

???????
return
?
0
;

}










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