socket程序

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socket程序

在Linux下写了个小的 socket程序，分为客户端和服务器端,服务端开一个端口(2000),做为一个daemon,等待客户的连接请求.一旦有客户连接,服务器端打印出客户端的IP地址和端口,并且向服务器端发送欢迎信息和时间.下面是服务端的代码(tcpserver.c).由于这只是个简单的程序，所以只用了单线程实现!

#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.

#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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