简单的TCP通信

//客户端：
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <string.h>

#define MAXLINE 1024
int main(int argc, char** argv)
{
int sockfd, ret;
struct sockaddr_in servaddr;
char recvline[MAXLINE];

if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
fprintf(stderr, "socket error.\n");
return -1;
}
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(20015);
if((inet_pton(AF_INET, (char*)"192.168.0.130", &servaddr.sin_addr)) <= 0)
{
fprintf(stderr, "inet_pton error.\n");
return -1;
}

if(connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0)
{
fprintf(stderr, "connect error.\n");
return -1;
}

while((ret = read(sockfd, recvline, sizeof(recvline))) > 0)
{
recvline[ret] = 0;
if(fputs(recvline, stdout) == EOF)
{
fprintf(stderr, "fputs error..\n");
return -1;
}
}
if(ret < 0)
fprintf(stderr, "read error..\n");
printf("\n");
exit(0);
}

//服务器端
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <ctime>

int main(int argc, char** argv)
{
int listenfd, connfd, ret;
struct sockaddr_in servaddr, cliaddr;
time_t now;
char cliIp[1024] = {0};
char buff[1024];

bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(20015);
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);

if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
fprintf(stderr, "socket error.\n");
return -1;
}
ret = bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr));
if(ret < 0)
{
fprintf(stderr, "bind error..%d\n", ret);
return -1;
}

listen(listenfd, 5);

for(;;)
{
socklen_t clilen = sizeof(clilen);
connfd = accept(listenfd, (struct sockaddr*)&cliaddr, &clilen);
if(connect < 0)
{
fprintf(stderr, "accept error..\n");
return -1;
}
now = time(NULL);
snprintf(cliIp, sizeof(cliIp), "From %s:%d:\n   ", inet_ntoa(cliaddr.sin_addr), cliaddr.sin_port) ;
snprintf(buff, sizeof(buff), "%s\n", ctime(&now));
strcat(cliIp, buff);
ret = write(connfd, cliIp, sizeof(cliIp));
ret = close(connfd);
if(ret < 0)
{
fprintf(stderr, "close error..\n");
return -1;
}
}

}

$ ./a.out
From 0.176.121.183:10124:
Sun Jul  5 11:56:26 2015