[unix-history] / usr / src / sys / deprecated / netimp / if_imphost.h

/*      if_imphost.h    4.2     82/02/12        */

/*
* Host structure used with IMP's.
* Used to hold outgoing packets which
* would exceed allowed RFNM count.
*
* These structures are packed into
* mbuf's and kept as small as possible.
*/
struct host {
       struct  mbuf *h_q;              /* holding queue */
       struct  in_addr h_addr;         /* host's address */
       u_short h_status;               /* host status */
       u_char  h_rfnm;                 /* # outstanding rfnm's */
       u_char  h_refcnt;               /* reference count */
};

#define HOSTS_DOWN      0               /* host believed down */
#define HOSTS_UP        128             /* host up */

/*
* Host structures, as seen inside an mbuf.
* Hashing on the host address is used to
* select an index into the first mbuf.  Collisions
* are then resolved by searching successive
* mbuf's at the same index.  Reclamation is done
* automatically at the time a structure is free'd.
*/
#define HPMBUF  ((MLEN - sizeof(int)) / sizeof(struct host))
#define HOSTHASH(a)     ((a.s_addr) % HPMBUF)

struct hmbuf {
       int     hm_count;               /* # of struct's in use */
       struct  host hm_hosts[HPMBUF];  /* data structures proper */
};

#ifdef KERNEL
struct host *hostlookup();
struct host *hostenter();
#endif