client.c和server.c 网络套接字socket编程热身程序

/*server.c*/
#include <stdio.h>
#include <arpa/inet.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <unistd.h>

#define  err_log(errlog) do{ perror(errlog); exit(1);}while(0)

int main(int argc, const char *argv[])
{
int sockfd;
int acceptfd;
struct sockaddr_in  serveraddr, clientaddr;

if(argc != 3)
{
fprintf(stderr,"Usage:%s serverip port.\n", argv[0]);
return -1;
}

if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
err_log("fail to socket");
}

serveraddr.sin_family = AF_INET;
serveraddr.sin_addr.s_addr = inet_addr(argv[1]);
serveraddr.sin_port = htons(atoi(argv[2]));

if(bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)
{
err_log("fail to bind");
}

if(listen(sockfd, 15) < 0)
{
err_log("fail to listen");
}

socklen_t  addrlen = sizeof(struct sockaddr_in);
acceptfd = accept(sockfd, (struct sockaddr *)&clientaddr, &addrlen);

if(acceptfd < 0)
{
err_log("fail to acceptfd");
}

printf("%s --> %d\n", inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port));

close(acceptfd);
close(sockfd);

return 0;
}

/*client*/
#include <stdio.h>
#include <arpa/inet.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <unistd.h>

#define  err_log(errlog) do{ perror(errlog); exit(1);}while(0)

int main(int argc, const char *argv[])
{
int sockfd;
int acceptfd;
struct sockaddr_in  serveraddr, clientaddr;

if(argc != 3)
{
fprintf(stderr,"Usage:%s serverip port.\n", argv[0]);
return -1;
}

if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
err_log("fail to socket");
}

serveraddr.sin_family = AF_INET;
serveraddr.sin_addr.s_addr = inet_addr(argv[1]);
serveraddr.sin_port = htons(atoi(argv[2]));

if(connect(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)
{
err_log("fail to connect");
}

close(sockfd);

return 0;
}