UNIX Socket UDP 코드

클라이언트

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

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

// UDP       -Client

int main(int argc, char* argv[])
{
	if (argc < 2)
	{
		printf("Please input something!\r
");
		exit(1);
	}

	
	//    UDP   ，  SOCK_DGRAM,   SOCK_STREAM
	int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP/*TCP  0*/);
	if (sock < 0)
	{
		printf("       ！\r
");
		exit(1);
	}

	// Send to
	struct sockaddr_in toAddr;
	memset(&toAddr, 0, sizeof(toAddr));
	toAddr.sin_family = AF_INET;
	toAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	toAddr.sin_port = htons(4000);

	// Start to send to
	if (sendto(sock, argv[1], strlen(argv[1]), 0, (struct sockaddr*)&toAddr, sizeof(toAddr)) != strlen(argv[1]))
	{
		printf("sendto()      !,\r
");
		close(sock);
		exit(1);
	}

	// Receive form
	struct sockaddr_in fromAddr;
	char recvBuffer[128] = {0};
	unsigned int fromLen = sizeof(fromAddr);
	
	if( recvfrom(sock, recvBuffer, 128, 0, (struct sockaddr*)&fromAddr, &fromLen) < 0)
	{
		printf("recvfrom()      !,\r
");
		close(sock);
		exit(1);
	}

	//             
	printf("recvfrom()result: %s\r
", recvBuffer);
	close(sock);
	return 0;
}

서비스 단말기

// UDP Server

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

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

int main()
{

	// Create UDP socket
	int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	
	if (sock < 0)
	{
		printf("Create socket faild\r
");
		exit(1);
	}

	// Bind socket and the client of send link request
	struct sockaddr_in fromAddr;
	memset(&fromAddr, 0, sizeof(fromAddr));
	fromAddr.sin_family = AF_INET;
	fromAddr.sin_addr.s_addr = htonl(INADDR_ANY);
	fromAddr.sin_port = htons(4000);
	
	if (bind(sock, (struct sockaddr*)&fromAddr, sizeof(fromAddr)) < 0)
	{
		printf("Bind socket faild!\r
");
		close(sock);
		exit(1);
	}
	
	struct sockaddr_in toAddr;
	char recvBuffer[128] = {0};
	int recvLen = -1;
	unsigned int addrLen = sizeof(toAddr);
	
	while(1)
	{
		if ((recvLen = recvfrom(sock, recvBuffer, 128, 0, (struct sockaddr*)&toAddr, &addrLen)) < 0)
		{
			printf("Receive message faild!\r
");
			close(sock);
			exit(1);
		}
		
		if (recvLen > 0)
		{
			printf("Recive message:%s\r
", recvBuffer);
		}

		if (sendto(sock, recvBuffer, recvLen, 0, (struct sockaddr*)&toAddr, sizeof(toAddr)) != recvLen)
		{
			printf("sendto faild\r
");
			close(sock);
			exit(1);
		}
	}
	
	close(sock);
	return 0;
}