extern int setup_listen_socket(const sockaddr_t *);
extern int setup_vpn_in_socket(const sockaddr_t *);
extern void send_packet(const struct node_t *, vpn_packet_t *);
extern int setup_listen_socket(const sockaddr_t *);
extern int setup_vpn_in_socket(const sockaddr_t *);
extern void send_packet(const struct node_t *, vpn_packet_t *);