cleanup

[unix-history] / usr / src / sys / net / if.h

/*      if.h    4.6     81/12/03        */

/*
* Structures defining a network interface, providing a packet
* transport mechanism (ala level 0 of the PUP protocols).
*
* Each interface accepts output datagrams of a specified maximum
* length, and provides higher level routines with input datagrams
* received from its medium.
*
* Output occurs when the routine if_output is called, with three parameters:
*      (*ifp->if_output)(ifp, m, pf)
* Here m is the mbuf chain to be sent and pf is the protocol family
* of the internetwork datagram format in which the data is wrapped
* (e.g. PF_PUP or PF_INET).  The output routine encapsulates the
* supplied datagram if necessary, and then transmits it on its medium.
*
* On input, each interface unwraps the data received by it, and either
* places it on the input queue of a internetwork datagram routine
* and posts the associated software interrupt, or passes the datagram to a raw
* packet input routine.
*
* Routines exist for locating interfaces by their internet addresses
* or for locating a interface on a certain network, as well as more general
* routing and gateway routines maintaining information used to locate
* interfaces.  These routines live in the files if.c and ip_ggp.c.
*/

/*
* Structure defining a queue for a network interface.
*
* (Would like to call this struct ``if'', but C isn't PL/1.)
*/
struct ifnet {
       char    *if_name;               /* name, e.g. ``en'' or ``lo'' */
       short   if_unit;                /* sub-unit for lower level driver */
       short   if_mtu;                 /* maximum transmission unit */
       short   if_net;                 /* network number of interface */
       int     if_host[2];             /* local net host number */
       struct  in_addr if_addr;        /* internet address of interface */
       struct  ifqueue {
               struct  mbuf *ifq_head;
               struct  mbuf *ifq_tail;
       } if_snd;                       /* output queue */
/* procedure handles */
       int     (*if_init)();           /* init routine */
       int     (*if_output)();         /* output routine */
       int     (*if_ubareset)();       /* uba reset routine */
/* generic interface statistics */
       int     if_ipackets;            /* packets received on interface */
       int     if_ierrors;             /* input errors on interface */
       int     if_opackets;            /* packets sent on interface */
       int     if_oerrors;             /* output errors on interface */
       int     if_collisions;          /* collisions on csma interfaces */
/* end statistics */
       struct  ifnet *if_next;
};

/*
* Output queues (ifp->if_snd) and internetwork datagram level (pup level 1)
* input routines have queues of messages stored on ifqueue structures
* (defined above).  Entries are added to and deleted from these structures
* by these macros, which should be called with ipl raised to splimp().
*/
#define IF_ENQUEUE(ifq, m) { \
       (m)->m_act = 0; \
       if ((ifq)->ifq_tail == 0) \
               (ifq)->ifq_head = m; \
       else \
               (ifq)->ifq_tail->m_act = m; \
       (ifq)->ifq_tail = m; \
}
#define IF_DEQUEUE(ifq, m) { \
       (m) = (ifq)->ifq_head; \
       if (m) { \
               if (((ifq)->ifq_head = (m)->m_act) == 0) \
                       (ifq)->ifq_tail = 0; \
               (m)->m_act = 0; \
       } \
}

#ifdef KERNEL
#ifdef INET
struct  ifqueue ipintrq;                /* ip packet input queue */
#endif
struct  ifqueue rawintrq;               /* raw packet input queue */
struct  ifnet *ifnet;
struct  ifnet *if_ifwithaddr(), *if_ifonnetof(), *if_gatewayfor();
struct  in_addr if_makeaddr();
#endif