client.c

在linux下实现的client/server模式的程序

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

#define MAX_CONNECT 2

static int libsk_create_server(char *ip, short port)
{       
	int listenfd;
	struct sockaddr_in cliaddr, servaddr;

	listenfd = socket(AF_INET, SOCK_STREAM, 0);

	bzero(&servaddr, sizeof(servaddr));

	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = inet_addr(ip);
	servaddr.sin_port = htons(port);

	bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));

	if(listen(listenfd, MAX_CONNECT) < 0)
	{
		listenfd = -1;
	}

	return listenfd;
}

static int libsk_accept(int sk)
{
	int fd;
	struct sockaddr_in addr;
	int sin_size=sizeof(struct sockaddr_in);
	fd = accept(sk , (struct sockaddr*)&addr , &sin_size);
	return fd;
}

static int libsk_connect_to(char *serverip, short port)
{
	int fd, ret;
	struct sockaddr_in servaddr;

	if(!serverip)
	{
	}
	fd = socket(AF_INET, SOCK_STREAM, 0);

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(port);
	inet_pton(AF_INET, serverip, &servaddr.sin_addr);
	ret = connect(fd, (struct sockaddr *) &servaddr, sizeof(servaddr));
	if(ret == -1)
	{
		close(fd);
		fd = -1;
	}

	return fd;
}

static int libsk_close(int sk)
{
	if((sk != 0) && (sk != -1))
	{
		close(sk);
	}
	return 0;
}

int main(int argc, char *argv[])
{
	int  sk;

	if(argc < 3)
	{
		printf("use:%s server port data", argv[0]);
		exit(0);
	}


	sk = libsk_connect_to(argv[1], atoi(argv[2]));
	if(sk < 0)
	{
		printf("connect to server failed\n");
		exit(0);
	}
	else
	{
		char buf[32];
		memset(buf , 0 , 32);
		if(argc >= 4)
		{
			int size = strlen(argv[3]) > 32 ? 32 : strlen(argv[3]);
			printf("size = %d strlen(argv[3]) %d \n" , size , strlen(argv[3]));
			memcpy(buf , argv[3] , size);
		}
		else
		{
			snprintf(buf , 32 , "%s" , "user put null\n");
		}
		write(sk, buf, 32);
		libsk_close(sk);
	}

	exit(0);
}