udpsend.c

linux下UDP消息发送及接收 在UBUNTU 8.10下测试通过

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define BUFLEN 255

int main(int argc, char **argv)
{
	struct sockaddr_in peeraddr, myaddr;
	int sockfd;
	char recmsg[BUFLEN + 1];
	unsigned int socklen;

	/* 创建 socket 用于UDP通讯 */
	sockfd = socket(AF_INET, SOCK_DGRAM, 0);
	if (sockfd < 0) {
		printf("socket creating error\n");
		exit(1);
	}

	socklen = sizeof(struct sockaddr_in);

	/* 设置对方的端口和IP信息 */
	memset(&peeraddr, 0, socklen);
	peeraddr.sin_family = AF_INET;
	if (argv[2]) peeraddr.sin_port = htons(atoi(argv[2]));
	else peeraddr.sin_port = htons(7838);

	if (argv[1]) {
		/* 注意这里设置的对方地址是指组播地址，而不是对方的实际IP地址 */
		if (inet_pton(AF_INET, argv[1], &peeraddr.sin_addr) <= 0) {
			printf("wrong group address!\n");
			exit(0);
		}
	} else {
		printf("no group address!\n");
		exit(0);
	}

	/* 设置自己的端口和IP信息 */
	memset(&myaddr, 0, socklen);
	myaddr.sin_family = AF_INET;
	if (argv[4]) myaddr.sin_port = htons(atoi(argv[4]));
	else myaddr.sin_port = htons(23456);

	if (argv[3]) {
		if (inet_pton(AF_INET, argv[3], &myaddr.sin_addr) <= 0) {
			printf("self ip address error!\n");
			exit(0);
		}
	} else myaddr.sin_addr.s_addr = INADDR_ANY;

	/* 绑定自己的端口和IP信息到socket上 */

	if (bind(sockfd, (struct sockaddr *) &myaddr,sizeof(struct sockaddr_in)) == -1) {
		printf("Bind error\n");
		exit(0);
	}

	/* 循环接受用户输入的消息发送组播消息 */
	for (;;) {
	/* 接受用户输入 */
		bzero(recmsg, BUFLEN + 1);
		if (fgets(recmsg, BUFLEN, stdin) == (char *) EOF) exit(0);

		/* 发送消息 */
		if (sendto(sockfd, recmsg, strlen(recmsg), 0,(struct sockaddr *) &peeraddr,sizeof(struct sockaddr_in)) < 0) {
			printf("sendto error!\n");
			exit(3);
		}

		printf("...... send ok\n");
		/* 判断退出 */
		if (strcmp(recmsg,"exit\n")==0)  {
			close(sockfd);
			exit(1);
		}
	}

}