socket简单例程

服务端：

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<errno.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>

#define MAXLINE 4096

int main(int argc, char** argv)
{
int listenfd, connfd;
struct sockaddr_in servaddr, addr;
char buff[4096];
int n;
socklen_t addr_len;
char peerip[18];

if( (listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ){
printf("create socket error: %s(errno: %d) ",strerror(errno),errno);
exit(0);
}

memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(6666);

if( bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1){
printf("bind socket error: %s(errno: %d) ",strerror(errno),errno);
exit(0);
}

if( listen(listenfd, 10) == -1){
printf("listen socket error: %s(errno: %d) ",strerror(errno),errno);
exit(0);
}

printf("======waiting for client's request====== ");
while(1){
if( (connfd = accept(listenfd, (struct sockaddr*)&addr, &addr_len)) == -1){
printf("accept socket error: %s(errno: %d)",strerror(errno),errno);
continue;
}
memset(&addr, 0, addr_len);
getpeername(connfd, (struct sockaddr *)&addr, &addr_len);
printf("IP: %d ", addr.sin_addr.s_addr);
printf("address:%s:%d",inet_ntop(AF_INET, &addr.sin_addr, peerip, sizeof(peerip)), ntohs(addr.sin_port));

n = recv(connfd, buff, MAXLINE, 0);
buff[n] = '';
printf("recv msg from client: %s ", buff);
close(connfd);
}
printf("close listenfd ");
close(listenfd);
}

客户端：

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<errno.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>

#define MAXLINE 4096

int main(int argc, char** argv)
{
int sockfd, n;
char recvline[4096], sendline[4096];
struct sockaddr_in servaddr;

if( argc != 2){
printf("usage: ./client <ipaddress> ");
exit(0);
}

if( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){
printf("create socket error: %s(errno: %d) ", strerror(errno),errno);
exit(0);
}

memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(6666);
if( inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0){
printf("inet_pton error for %s ",argv[1]);
exit(0);
}

if( connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0){
printf("connect error: %s(errno: %d) ",strerror(errno),errno);
exit(0);
}

printf("send msg to server: ");
fgets(sendline, 4096, stdin);
if( send(sockfd, sendline, strlen(sendline), 0) < 0)
{
printf("send msg error: %s(errno: %d) ", strerror(errno), errno);
exit(0);
}

close(sockfd);
exit(0);
}