usr/src/sys/netinet/in_systm.h

/* in_systm.h 4.1 81/11/08 */

/*
 * Miscellaneous internetwork
 * definitions for kernel.
 */

/* THESE SHOULD BE ELIMINATED */
#define NCON            20              /* SHOULD BE DYNAMIC, NO LIMIT */
#define NHOST           20              /* SHOULD BE SOME DYNAMIC LIMIT */
/* END SHOULD BE ELIMINATED */

/*
 * Network types.
 *
 * Internally the system keeps counters in the headers with the bytes
 * swapped so that VAX instructions will work on them.  It reverses
 * the bytes before transmission at each protocol level.  The n_ types
 * represent the types with the bytes in ``high-ender'' order.
 */
typedef u_short n_short;                /* short as received from the net */
typedef u_long  n_long;                 /* long as received from the net */
typedef u_long  seq_t;                  /* sequence number */

typedef u_long  n_time;                 /* ms since 00:00 GMT, byte rev */

/*
 * The network runs as a software interrupt process.
 * You can switch into the network by doing splnet() and return by splx().
 * The software interrupt level for the network is higher than the software
 * level for the clock (so you can enter the network in routines called
 * at timeout time).  Splimp is an ipl high enough to block all imps.
 * While manipulating the mbuf buffer pool you have to block imps since
 * allocation occurs at interrupt level.  (It would be easier to
 * use interlocked instructions, but we don't do this yet.)
 */
#define splimp          spl5
#define setsoftnet()    mtpr(SIRR, 12)
/* splnet is defined in ../sys/asm.sed */

/*
 * Network statistics record.
 *
 * SHOULD BE KEPT PER INTERFACE, AND WITH CNT, RATE, SUM.
 */
struct  net_stat {
        int     imp_resets;             /* # times imp reset */
        int     imp_flushes;            /* # packets flushed by imp */
        int     imp_drops;              /* # msgs from imp no-one wants */
        int     m_drops;                /* # mbuf drops from lack of bufs */
        int     ip_badsum;              /* # bad ip checksums */
        int     t_badsum;               /* # bad tcp checksums */
        int     t_badsegs;              /* # bad tcp segments */
        int     t_unack;                /* # tcp segs placed on rcv_unack */
};

#ifdef  KERNEL
int     nnetpages;
extern  struct net_stat netstat;                /* net statistics block */
#endif

#ifdef KPROF
#include "../inet/count.h"
#define COUNT(i)        nrcount[i]++
int     nrcount[NCOUNTERS+1];
#else
#define COUNT(i)
#endif