struct pcap_rmtauth{
　　int    type
     //Type of the authentication required.
　　char *    username
     //Zero-terminated string containing the username that has to be used on the remote machine for authentication.
　　char *    password
     //Zero-terminated string containing the password that has to be used on the remote machine for authentication. 
};
 

struct  pcap_if
{
    pcap_if *    next
    //if not NULL, a pointer to the next element in the list; NULL for the last element of the list
    char *    name
    //a pointer to a string giving a name for the device to pass to pcap_open_live()
    char *    description
    //if not NULL, a pointer to a string giving a human-readable description of the device
    pcap_addr *    addresses
    //a pointer to the first element of a list of addresses for the interface
    u_int    flags
    //PCAP_IF_ interface flags. Currently the only possible flag is PCAP_IF_LOOPBACK, that is set if the interface is a loopback interface.
};

struct  pcap_addr
{
    pcap_addr *    next
    //if not NULL, a pointer to the next element in the list; NULL for the last element of the list
    sockaddr *    addr
    //a pointer to a struct sockaddr containing an address
    sockaddr *    netmask
    //if not NULL, a pointer to a struct sockaddr that contains the netmask corresponding to the address pointed to by addr.
    sockaddr *    broadaddr
    //if not NULL, a pointer to a struct sockaddr that contains the broadcast address corre­ sponding to the address pointed to by addr; may be null if the interface doesn‘t support broadcasts
    sockaddr *    dstaddr
    //if not NULL, a pointer to a struct sockaddr that contains the destination address corre­ sponding to the address pointed to by addr; may be null if the interface isn‘t a point- to-point interface
};