【Linux网络编程】基于UDP的客户端/服务器程序

效果就像开晚会的表白墙或者上墙一样，多个udp客户端都可以给服务端发送消息。

服务端代码：

#include 
#include 
#include 
#include 
#include 
#include 

int main(int argc, char** argv)
{
	int sock = socket(AF_INET, SOCK_DGRAM, 0);
	if(sock < 0)
	{
		perror("socket");
		return 1;
	}

	//bind
	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]);

	if(bind(sock, (struct sockaddr*)&local, sizeof(local)) < 0 )
	{
		perror("bind");
		return 2;
	}


	char buf[1024];
	struct sockaddr_in remote;
	socklen_t  len = sizeof(remote);
	while(1)
	{
		ssize_t s = recvfrom(sock, buf, sizeof(buf) - 1, 0, (struct sockaddr*)&remote, &len);	
		if(s > 0)
		{
			buf[s] = 0;
			printf("client %s : port %d : say# %s \n",inet_ntoa(remote.sin_addr), ntohs(remote.sin_port), buf);
			sendto(sock, buf, strlen(buf),0,(struct sockaddr*)&remote, len);
		}
		else if( s == 0)
		{
		}
	}
	close(sock);
	printf("server\n");
	return 0;
}

客户端代码：

#include 
#include 
#include 
#include 
#include 
#include 

int main(int argc, char** argv)
{

	// 1. new socket
	int sock = socket(AF_INET, SOCK_DGRAM, 0);
	if(sock < 0)
	{
		perror("socket");
		return 1;
	}

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

	char buf[1024];

	socklen_t  len = sizeof(server);
	while(1)
	{
		printf("Please Enter #");
		fflush(stdout);
		ssize_t s = read(0, buf, sizeof(buf) - 1);
		if(s > 0)
		{
			buf[s] = 0;
			// send
			sendto(sock, buf, strlen(buf),0,(struct sockaddr*)&server, len);
			ssize_t _s = recvfrom(sock, buf, sizeof(buf) - 1, 0, NULL, NULL);
			printf("server echo# %s\n", buf);
		}
	}

	close(sock);
	return 0;
}

截图：

服务端：

客户端A：

客户端B：