socket通信

/* 
 * client.c 
 */

include "apue.h"
#include <netdb.h>
#include <errno.h>
#include <sys/socket.h>

#define BUFLEN 128
#define MAXSLEEP 128
#define PORT 3333  /* must be bigger than  1023 */

int 
createSocket(int domain, int socket_type, int protocol);
int 
connectRetry(int socket, const struct sockaddr *addr, socklen_t alen);
void
printUptime(int socket);

int 
main(int argc, char *argv[])
{
	struct hostent *host;
	struct sockaddr_in addr;
	if(argc < 2){
		fprintf(stderr, "Error: Please enter the server's hostname\n");
		exit(1);
	}
	if((host = gethostbyname(argv[1])) == NULL){
		fprintf(stderr, "Error: gethostbyname is wrong\n");
		exit(1);
	}
	int socket = createSocket(AF_INET, SOCK_STREAM, 0);
	
	addr.sin_family = AF_INET;  /* address faminly */
	addr.sin_port = htons(PORT);  /* connect port */
	addr.sin_addr.s_addr = inet_addr("192.168.1.203");

<span style="white-space:pre">	</span>/*addr.sin_addr.s_addr = htonl(INADDR_ANY);*/
	/*addr.sin_addr = *((struct in_addr *)host->h_addr_list);*/  /* connect address */
	/* addr.sin_zero */
	
	if(connectRetry(socket, (struct sockaddr *)&addr, sizeof(struct sockaddr)) < 0){
		fprintf(stderr, "Connectiong error: %s\n", strerror(errno));
	}else{
		//printUptime(socket);
	}

	close(socket);

	exit(0);
}

/*

 * 接收服务端返回给socket的数据，缓存在buf中

 */

void
printUptime(int socket)
{
	int n;
	char buf[BUFLEN];
	while ((n = recv(socket, buf, BUFLEN, 0)) > 0)
		if (buf != NULL)
			printf("%s", buf);
			//write(STDOUT_FILENO, buf, n);
	if(n < 0)
		printf("recv error\n");
}
/*

 * 创建一个socket

 */
int 
createSocket(int domain, int socket_type, int protocol)
{
	int new_socket, err;

	if( ( new_socket = socket ( domain, socket_type, protocol) ) < 0 ){
		fprintf(stderr, "Error:%s\n", strerror(errno));
		return -1;
	}

	return new_socket;
}
/*

 * 建立与服务端的连接，并在规定时间内不断重连

 */
int 
connectRetry(int socket, const struct sockaddr *addr, socklen_t alen)
{
	int nsec;

	//for( nsec = 1; nsec <= MAXSLEEP; nsec <<=1 ){
		if( connect( socket, addr, alen ) == 0 ){
			/* Coonection accepted*/
			return 0;
		}
		/* Delay before trying again */
	//	if( nsec <= MAXSLEEP/2 )
	//		sleep(nsec);
	//}
	return -1;
}

/*
 * server.c
 */
#include <errno.h>
#include <malloc.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/socket.h>

#define BUFLEN 1024
#define MAX_CONN 100
#define SERVER_PORT 3333

int 
initServer(int socket_type, const struct sockaddr *addr, socklen_t alen, int qlen);
void
acceptServer(int socket, char *buf);
static void
writeBuf(int socket, char *buf);

int
main(int argc, char* argv[])
{
	struct hostent *host;
	struct sockaddr_in addr;
	char *buf = malloc(BUFLEN * sizeof(char));
	
	if( argc < 2 ){
		fprintf(stderr, "Please enter the host name\n");
		exit(1);
	}
	if( (host = gethostbyname(argv[1])) == NULL ){
		fprintf(stderr, "Error: get host name error\n");
		exit(1);
	}
	addr.sin_family = AF_INET;
	addr.sin_port = htons(3333);
	/*addr.sin_addr = *((struct in_addr *)host->h_addr_list);*/
	addr.sin_addr.s_addr = inet_addr("192.168.1.203");
	int socket = initServer(SOCK_STREAM, (struct sockaddr *)&addr, sizeof(struct sockaddr), MAX_CONN); 
	acceptServer(socket, "hello");	


	return 0;
}
/*

 * 初始化服务端socket并将其绑定，开始监听客户端请求

 */
int
initServer(int socket_type, const struct sockaddr *addr, socklen_t alen, int qlen)
{
	int newSocket;
	if( (newSocket = socket (addr->sa_family, socket_type, 0)) < 0  ){
		printf("socket is : %d\n", newSocket);
		return -1;
	}
	if( bind(newSocket, addr, alen) < 0){
		perror("Error: bind wrong");
		return -1;
	}
	if( (socket_type == SOCK_STREAM) || (socket_type == SOCK_SEQPACKET) ){
		if( listen(newSocket, qlen) < 0 ){
			perror("Error: listen wrong\n");
			return -1;
		}
	}
	return newSocket;
}
/*

 * 获取监听到的客户端socket进程

 */
void 
acceptServer(int socket, char *buf)
{
	int accSocket;
	while(1){
		accSocket = accept(socket, NULL, NULL);
		if(accSocket < -1){
			perror("Error: accept error\n");
		}
		printf("%d\n", accSocket);
		writeBuf(accSocket, buf);
	}
}
/*

 * 向监听到的socket里面写数据，发送给客户端

 */
static void
writeBuf(int socket, char *buf)
{
	if(socket < 0 || buf == NULL)
		send(socket, "", 0, 0);
	send(socket, buf, strlen(buf), 0);
}