#ifndef _UNP_H_#define _UNP_H_#include <sys/socket.h>#include <netinet/in.h>#ifdef __cplusplusextern "C"{#endifunsigned short in_cksum(unsigned short *addr, int len);int mcast_setif(int sockfd, unsigned int ifindex, const char *ifname);int mcast_setloop(int sockfd, int loop);int mcast_join(int sockfd, const struct sockaddr *sockaddr,socklen_t addrlen,			   unsigned int ifindex, const char *ifname);int getifaddr(int family, unsigned int ifindex, const char *ifname,			  void *ifaddr);#ifdef __cplusplus}#endif#endif