Linux下搭建一個簡單的UDP通信

基礎知識

UDP和TCP的區別：

1、TCP是面向連接的，而UDP是非面向連接的，因此TCP更可靠

2、UDP的server端的socket不需要監聽

3、二者的server端都需要綁定

代碼實現：

Server端：

/*************************************************************************
	> File Name: server.c
	> Author: HonestFox
	> Mail: [email protected] 
	> Created Time: Sun 24 Jul 2016 09:23:45 PM CST
 ************************************************************************/

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

static void usage(const char *proc)
{
	printf("usage : %s  IP : %s\n", proc, proc);
}

int main(int argc, char *argv[])
{
	if( argc != 3)
	{
		usage(argv[0]);
		return 1;
	}

	int sock = socket(AF_INET, SOCK_DGRAM, 0);
	if( sock < 0)
	{
		perror("socket");
		exit(1);
	}
	

	//1.Create a Socket
	struct sockaddr_in local;
	local.sin_family = AF_INET;
	local.sin_port = htons(atoi(argv[2]) );
	local.sin_addr.s_addr = inet_addr(argv[1]);
	
	//2.Bind
	if(bind(sock, (struct sockaddr*)&local, sizeof(local) ) < 0)
	{
		perror("bind error");
		return 2;
	}

	//3.Receive & Send
	int done = 0;
	struct sockaddr_in peer;
	socklen_t len = sizeof(peer);
	char buf[1024];
	while(!done)
	{
		memset(buf, '\0', sizeof(buf));
		recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr*)&peer, &len);
		printf("client: %s\n", buf);
	}

	return 0;
}

/*************************************************************************
	> File Name: client.c
	> Author: HonestFox
	> Mail: [email protected] 
	> Created Time: Sun 24 Jul 2016 09:23:41 PM CST
 ************************************************************************/
#include<stdio.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<string.h>
#include<netinet/in.h>
#include<unistd.h>
#include<stdlib.h>
static void usage(const char *proc)
{
	printf("usage : %s  IP : %s\n", proc, proc);
}

int main(int argc, char *argv[])
{
	if( argc != 3)
	{
		usage(argv[0]);
		return 1;
	}

	int sock = socket(AF_INET, SOCK_DGRAM, 0);
	if( sock < 0)
	{
		perror("socket");
		exit(1);
	}

	//1.Create a Socket
	struct sockaddr_in remote;
	remote.sin_family = AF_INET;
	remote.sin_port = htons(atoi(argv[2]) );
	remote.sin_addr.s_addr = inet_addr(argv[1]);
	
	//2.No Need to Bind

	//3 Send & Receive
	int done = 0;
	struct sockaddr_in peer;
	socklen_t len = sizeof(peer);
	char buf[1024];
	while(!done)
	{
		memset(buf, '\0', sizeof(buf));
		printf("plz enter: ");
		fflush(stdout);
		ssize_t _s = read(0, buf, sizeof(buf) - 1);
		if(_s > 0)
		{
			buf[_s - 1] = '\0';
			sendto(sock, buf, sizeof(buf), 0, (struct sockaddr*)&remote, sizeof(remote));
			memset(buf, '\0', sizeof(buf));
		}
	}
	
	return 0;
}

要想像即時通訊軟件那樣實現聊天的功能，還在研究ing