usr/src/sys/netinet/in_pcb.h

/*      in_pcb.h        4.2     81/12/03        */

/*
 * Common structure pcb for internet protocol implementation.
 * Here are stored pointers to local and foreign host table
 * entries, local and foreign socket numbers, and pointers
 * up (to a socket structure) and down (to a protocol-specific)
 * control block.
 */
struct inpcb {
        struct  inpcb *inp_next,*inp_prev;
                                        /* pointers to other pcb's */
        struct  inpcb *inp_head;        /* pointer back to chain of inpcb's
                                           for this protocol */
        struct  in_addr inp_faddr;      /* foreign host table entry */
        u_short inp_fport;              /* foreign port */
        struct  in_addr inp_laddr;      /* local host table entry */
        u_short inp_lport;              /* local port */
        struct  socket *inp_socket;     /* back pointer to socket */
        caddr_t inp_ppcb;               /* pointer to per-protocol pcb */
};

#define sotoinpcb(so)   ((struct inpcb *)(so)->so_pcb)

#ifdef KERNEL
struct  inpcb *in_pcblookup();
#endif