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[unix-history] / usr / src / sys / sys / mbuf.h

/*      mbuf.h  4.13    82/06/14        */

/*
* Constants related to memory allocator.
*/
#define MSIZE           128                     /* size of an mbuf */
#define MMINOFF         12                      /* mbuf header length */
#define MTAIL           4
#define MMAXOFF         (MSIZE-MTAIL)           /* offset where data ends */
#define MLEN            (MSIZE-MMINOFF-MTAIL)   /* mbuf data length */
#define NMBCLUSTERS     256
#define NMBPCL          (CLBYTES/MSIZE)         /* # mbufs per cluster */

/*
* Macros for type conversion
*/

/* network cluster number to virtual address, and back */
#define cltom(x) ((struct mbuf *)((int)mbutl + ((x) << CLSHIFT)))
#define mtocl(x) (((int)x - (int)mbutl) >> CLSHIFT)

/* address in mbuf to mbuf head */
#define dtom(x)         ((struct mbuf *)((int)x & ~(MSIZE-1)))

/* mbuf head, to typed data */
#define mtod(x,t)       ((t)((int)(x) + (x)->m_off))

struct mbuf {
       struct  mbuf *m_next;           /* next buffer in chain */
       u_long  m_off;                  /* offset of data */
       short   m_len;                  /* amount of data in this mbuf */
       short   m_free;                 /* is mbuf free? (consistency check) */
       u_char  m_dat[MLEN];            /* data storage */
       struct  mbuf *m_act;            /* link in higher-level mbuf list */
};

/* flags to m_get */
#define M_DONTWAIT      0
#define M_WAIT          1

/* flags to m_pgalloc */
#define MPG_MBUFS       0               /* put new mbufs on free list */
#define MPG_CLUSTERS    1               /* put new clusters on free list */
#define MPG_SPACE       2               /* don't free; caller wants space */

/* length to m_copy to copy all */
#define M_COPYALL       1000000000

#define MGET(m, i) \
       { int ms = splimp(); \
         if ((m)=mfree) \
               { if ((m)->m_free == 0) panic("mget"); (m)->m_free = 0; \
                 mbstat.m_mbfree--; mfree = (m)->m_next; (m)->m_next = 0; } \
         else \
               (m) = m_more(i); \
         splx(ms); }
#define MCLGET(m, i) \
       { int ms = splimp(); \
         if ((m)=mclfree) \
            {++mclrefcnt[mtocl(m)];mbstat.m_clfree--;mclfree = (m)->m_next;} \
         splx(ms); }
#define MFREE(m, n) \
       { int ms = splimp(); \
         if ((m)->m_free) panic("mfree"); (m)->m_free = 1; \
         if ((m)->m_off > MSIZE) { \
               (n) = (struct mbuf *)(mtod(m, int)&~0x3ff); \
               if (--mclrefcnt[mtocl(n)] == 0) \
                   { (n)->m_next = mclfree;mclfree = (n);mbstat.m_clfree++;} \
         } \
         (n) = (m)->m_next; (m)->m_next = mfree; \
         (m)->m_off = 0; (m)->m_act = 0; mfree = (m); mbstat.m_mbfree++; \
         splx(ms); }

/*
* Mbuf statistics.
*/
struct mbstat {
       short   m_mbufs;                /* mbufs obtained from page pool */
       short   m_mbfree;               /* mbufs on our free list */
       short   m_clusters;             /* clusters obtained from page pool */
       short   m_clfree;               /* free clusters */
       short   m_drops;                /* times failed to find space */
};

#ifdef  KERNEL
extern  struct mbuf mbutl[];            /* virtual address of net free mem */
extern  struct pte Mbmap[];             /* page tables to map Netutl */
struct  mbstat mbstat;
extern  int nmbclusters;
struct  mbuf *mfree, *mclfree;
char    mclrefcnt[NMBCLUSTERS];
struct  mbuf *m_get(),*m_getclr(),*m_free(),*m_more(),*m_copy(),*m_pullup();
caddr_t m_clalloc();
#endif