UDP的send、sendto和sendmsg测试代码

// mode:	0 call sendto
//			1 call sendmsg
//			2 call connect and send/sendmsg/write
void udp_test(int mode, const char* addr, unsigned short port, const char* text)
{
	int s = socket(AF_INET,SOCK_DGRAM,0);
	if (s<0)
	{
		printf("socket failed: %d\n",errno);
		return;
	}
	sockaddr_in sin;
	sin.sin_family = AF_INET;
	sin.sin_port = htons(port);
	sin.sin_addr.s_addr = inet_addr(addr);
	int len = strlen(text);
	int ret = 0;
	if (mode==0)
	{
		ret = sendto(s,text,len,0,(struct sockaddr*)&sin,sizeof(sin));
	}
	else if(mode==1)
	{
		struct msghdr msg;
		struct iovec iov;
		msg.msg_name = &sin;
		msg.msg_namelen = sizeof(sin);
		msg.msg_iov = &iov;
		msg.msg_iovlen = 1;
		msg.msg_iov->iov_base = (char*)text;
		msg.msg_iov->iov_len = len;
		msg.msg_control = 0;
		msg.msg_controllen = 0;
		msg.msg_flags = 0;	
		ret = sendmsg(s,&msg,0);
	}
	else if(mode==2)
	{
		if(connect(s,(struct sockaddr*)&sin,sizeof(sin))<0)
		{
			printf("socket failed: %d\n",errno);
			return;
		}
		ret = send(s,text,len,0);
	}
	printf("send %d byte to %s:%hu\n",ret,addr,port);
	close(s);
}

int main(int argc, const char **argv)
{
    if(argc<5)
        return -1;
    int msgid = atoi(argv[1]);

    udp_test(atoi(argv[1]),argv[2],atoi(argv[3]),argv[4]);

    return 0;
}

为了重复发，可以写个脚本循环调用

#!/bin/bash
while [ 1 ]
do
./udp_test 0 192.168.0.100 8999 "this is my words"
sleep 1
done