SSDP UDP broadcast ...

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
 
#define RESPONSE_BUFFER_LEN 1024
#define SSDP_MULTICAST      "239.255.255.250"
#define SSDP_PORT           1900
 
int main (int argc, const char * argv[])
{
	int sock;
	size_t ret;
	unsigned int socklen;
	struct sockaddr_in sockname;
	struct sockaddr clientsock;
	struct hostent *hostname;
	char data[] = 
    "M-SEARCH * HTTP/1.1\r\n"
    "Host: 239.255.255.250:1900\r\n"
    "Man: \"ssdp:discover\"\r\n"
    "ST:upnp:rootdevice\r\n"
    "MX:3\r\n"
    "\r\n";
	char buffer[RESPONSE_BUFFER_LEN];
	unsigned int len = RESPONSE_BUFFER_LEN;
	fd_set fds;
	struct timeval timeout;
	
	hostname = gethostbyname(SSDP_MULTICAST);
	hostname->h_addrtype = AF_INET;
	
	
	if((sock = socket(PF_INET, SOCK_DGRAM, 0)) == -1){
		printf("err: socket() failed");
		return -1;
	}
	
	memset((char*)&sockname, 0, sizeof(struct sockaddr_in));
	sockname.sin_family=AF_INET;
	sockname.sin_port=htons(SSDP_PORT);
	sockname.sin_addr.s_addr=*((unsigned long*)(hostname->h_addr_list[0]));
	
	ret=sendto(sock, data, strlen(data), 0, (struct sockaddr*) &sockname, 
			   sizeof(struct sockaddr_in));
	if(ret != strlen(data)){
		printf("err:sendto");
		return -1;
	}
	
	/* Get response */
	FD_ZERO(&fds);
	FD_SET(sock, &fds);
	timeout.tv_sec=10;
	timeout.tv_usec=10;
	
	if(select(sock+1, &fds, NULL, NULL, &timeout) < 0){
		printf("eer:select");
		return -1;
	}
	if(FD_ISSET(sock, &fds)){
		socklen=sizeof(clientsock);
		if((len = recvfrom(sock, buffer, len, MSG_PEEK, 
						   &clientsock, &socklen)) == (size_t)-1){
			printf("err: recvfrom");
			return -1;
		}
		buffer[len]='\0';
		close(sock);
		
		/* Check the HTTP response code */
		if(strncmp(buffer, "HTTP/1.1 200 OK", 12) != 0){
			printf("err: ssdp parsing ");
			return -1;
		}
		
		printf(buffer);
		return 0;
		
	}else{
		
		printf("err: no ssdp answer");
		return -1;
	}
}

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