* 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, dst)
* Here m is the mbuf chain to be sent and dst is the destination address.
* 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
* Routines exist for locating interfaces by their 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 route.c
* Structure defining a queue for a network interface.
* (Would like to call this struct ``if'', but C isn't PL/1.)
* EVENTUALLY PURGE if_net AND if_host FROM STRUCTURE
char *if_name
; /* name, e.g. ``en'' or ``lo'' */
short if_unit
; /* sub-unit for lower level driver */
short if_mtu
; /* maximum transmission unit */
int if_net
; /* network number of interface */
short if_flags
; /* up/down, broadcast, etc. */
short if_timer
; /* time 'til if_watchdog called */
int if_host
[2]; /* local net host number */
struct sockaddr if_addr
; /* address of interface */
struct sockaddr ifu_broadaddr
;
struct sockaddr ifu_dstaddr
;
#define if_broadaddr if_ifu.ifu_broadaddr /* broadcast address */
#define if_dstaddr if_ifu.ifu_dstaddr /* other end of p-to-p link */
} if_snd
; /* output queue */
int (*if_init
)(); /* init routine */
int (*if_output
)(); /* output routine */
int (*if_reset
)(); /* bus reset routine */
int (*if_watchdog
)(); /* timer 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 */
#define IFF_UP 0x1 /* interface is up */
#define IFF_BROADCAST 0x2 /* broadcast address valid */
#define IFF_DEBUG 0x4 /* turn on debugging */
#define IFF_ROUTE 0x8 /* routing entry installed */
#define IFF_POINTOPOINT 0x10 /* interface is point-to-point link */
* 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_QFULL(ifq) ((ifq)->ifq_len >= (ifq)->ifq_maxlen)
#define IF_DROP(ifq) ((ifq)->ifq_drops++)
#define IF_ENQUEUE(ifq, m) { \
if ((ifq)->ifq_tail == 0) \
(ifq)->ifq_tail->m_act = m; \
#define IF_PREPEND(ifq, m) { \
(m)->m_act = (ifq)->ifq_head; \
if ((ifq)->ifq_tail == 0) \
#define IF_DEQUEUE(ifq, m) { \
if (((ifq)->ifq_head = (m)->m_act) == 0) \
#define IFNET_SLOWHZ 1 /* granularity is 1 second */
struct ifqueue ipintrq
; /* ip packet input queue */
struct ifqueue rawintrq
; /* raw packet input queue */
struct ifnet
*if_ifwithaddr(), *if_ifwithnet(), *if_ifwithaf();
struct ifnet
*if_ifonnetof();
struct in_addr
if_makeaddr();