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33 * @(#)mbuf.h 8.5 (Berkeley) 2/19/95
41 * Mbufs are of a single size, MSIZE (machine/machparam.h), which
42 * includes overhead. An mbuf may add a single "mbuf cluster" of size
43 * MCLBYTES (also in machine/machparam.h), which has no additional overhead
44 * and is used instead of the internal data area; this is done when
45 * at least MINCLSIZE of data must be stored.
48 #define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */
49 #define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */
51 #define MINCLSIZE (MHLEN + MLEN) /* smallest amount to put in cluster */
52 #define M_MAXCOMPRESS (MHLEN / 2) /* max amount to copy for compression */
55 * Macros for type conversion
56 * mtod(m,t) - convert mbuf pointer to data pointer of correct type
57 * dtom(x) - convert data pointer within mbuf to mbuf pointer (XXX)
58 * mtocl(x) - convert pointer within cluster to cluster index #
59 * cltom(x) - convert cluster # to ptr to beginning of cluster
61 #define mtod(m,t) ((t)((m)->m_data))
62 #define dtom(x) ((struct mbuf *)((intptr_t)(x) & ~(MSIZE-1)))
63 #define mtocl(x) (((uintptr_t)(x) - (uintptr_t)mbutl) >> MCLSHIFT)
64 #define cltom(x) ((caddr_t)((uintptr_t)mbutl + \
65 ((uintptr_t)(x) << MCLSHIFT)))
67 /* header at beginning of each mbuf: */
69 struct mbuf *mh_next; /* next buffer in chain */
70 struct mbuf *mh_nextpkt; /* next chain in queue/record */
71 caddr_t mh_data; /* location of data */
72 int mh_len; /* amount of data in this mbuf */
73 short mh_type; /* type of data in this mbuf */
74 short mh_flags; /* flags; see below */
77 /* record/packet header in first mbuf of chain; valid if M_PKTHDR set */
79 struct ifnet *rcvif; /* rcv interface */
80 int len; /* total packet length */
82 /* variables for ip and tcp reassembly */
83 void *header; /* pointer to packet header */
86 /* description of external storage mapped into mbuf, valid if M_EXT set */
88 caddr_t ext_buf; /* start of buffer */
89 void (*ext_free) /* free routine if not the usual */
90 __P((caddr_t, u_int));
91 u_int ext_size; /* size of buffer, for ext_free */
92 void (*ext_ref) /* add a reference to the ext object */
93 __P((caddr_t, u_int));
100 struct pkthdr MH_pkthdr; /* M_PKTHDR set */
102 struct m_ext MH_ext; /* M_EXT set */
103 char MH_databuf[MHLEN];
106 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */
109 #define m_next m_hdr.mh_next
110 #define m_len m_hdr.mh_len
111 #define m_data m_hdr.mh_data
112 #define m_type m_hdr.mh_type
113 #define m_flags m_hdr.mh_flags
114 #define m_nextpkt m_hdr.mh_nextpkt
115 #define m_act m_nextpkt
116 #define m_pkthdr M_dat.MH.MH_pkthdr
117 #define m_ext M_dat.MH.MH_dat.MH_ext
118 #define m_pktdat M_dat.MH.MH_dat.MH_databuf
119 #define m_dat M_dat.M_databuf
122 #define M_EXT 0x0001 /* has associated external storage */
123 #define M_PKTHDR 0x0002 /* start of record */
124 #define M_EOR 0x0004 /* end of record */
125 #define M_PROTO1 0x0008 /* protocol-specific */
127 /* mbuf pkthdr flags, also in m_flags */
128 #define M_BCAST 0x0100 /* send/received as link-level broadcast */
129 #define M_MCAST 0x0200 /* send/received as link-level multicast */
130 #define M_FRAG 0x0400 /* packet is a fragment of a larger packet */
132 /* flags copied when copying m_pkthdr */
133 #define M_COPYFLAGS (M_PKTHDR|M_EOR|M_PROTO1|M_BCAST|M_MCAST)
136 #define MT_FREE 0 /* should be on free list */
137 #define MT_DATA 1 /* dynamic (data) allocation */
138 #define MT_HEADER 2 /* packet header */
139 /*efine MT_SOCKET 3*/ /* socket structure */
140 /*efine MT_PCB 4*/ /* protocol control block */
141 /*efine MT_RTABLE 5*/ /* routing tables */
142 /*efine MT_HTABLE 6*/ /* IMP host tables */
143 /*efine MT_ATABLE 7*/ /* address resolution tables */
144 #define MT_SONAME 8 /* socket name */
145 /*efine MT_SOOPTS 10*/ /* socket options */
146 #define MT_FTABLE 11 /* fragment reassembly header */
147 /*efine MT_RIGHTS 12*/ /* access rights */
148 /*efine MT_IFADDR 13*/ /* interface address */
149 #define MT_CONTROL 14 /* extra-data protocol message */
150 #define MT_OOBDATA 15 /* expedited data */
152 /* flags to m_get/MGET */
158 * Normal mbuf clusters are normally treated as character arrays
159 * after allocation, but use the first word of the buffer as a free list
160 * pointer while on the free list.
163 union mcluster *mcl_next;
164 char mcl_buf[MCLBYTES];
168 * mbuf utility macros:
171 * prevents a section of code from from being interrupted by network
174 #define MBUFLOCK(code) \
175 do { int ms = splimp(); \
181 * mbuf allocation/deallocation macros:
183 * MGET(struct mbuf *m, int how, int type)
184 * allocates an mbuf and initializes it to contain internal data.
186 * MGETHDR(struct mbuf *m, int how, int type)
187 * allocates an mbuf and initializes it to contain a packet header
190 #define MGET(m, how, type) { \
191 int _ms = splimp(); \
193 (void)m_mballoc(1, (how)); \
194 if (((m) = mmbfree) != 0) { \
195 mmbfree = (m)->m_next; \
196 mbstat.m_mtypes[MT_FREE]--; \
197 (m)->m_type = (type); \
198 mbstat.m_mtypes[type]++; \
199 (m)->m_next = (struct mbuf *)NULL; \
200 (m)->m_nextpkt = (struct mbuf *)NULL; \
201 (m)->m_data = (m)->m_dat; \
206 (m) = m_retry((how), (type)); \
210 #define MGETHDR(m, how, type) { \
211 int _ms = splimp(); \
213 (void)m_mballoc(1, (how)); \
214 if (((m) = mmbfree) != 0) { \
215 mmbfree = (m)->m_next; \
216 mbstat.m_mtypes[MT_FREE]--; \
217 (m)->m_type = (type); \
218 mbstat.m_mtypes[type]++; \
219 (m)->m_next = (struct mbuf *)NULL; \
220 (m)->m_nextpkt = (struct mbuf *)NULL; \
221 (m)->m_data = (m)->m_pktdat; \
222 (m)->m_flags = M_PKTHDR; \
226 (m) = m_retryhdr((how), (type)); \
231 * Mbuf cluster macros.
232 * MCLALLOC(caddr_t p, int how) allocates an mbuf cluster.
233 * MCLGET adds such clusters to a normal mbuf;
234 * the flag M_EXT is set upon success.
235 * MCLFREE releases a reference to a cluster allocated by MCLALLOC,
236 * freeing the cluster if the reference count has reached 0.
238 #define MCLALLOC(p, how) \
241 (void)m_clalloc(1, (how)); \
242 if (((p) = (caddr_t)mclfree) != 0) { \
243 ++mclrefcnt[mtocl(p)]; \
245 mclfree = ((union mcluster *)(p))->mcl_next; \
249 #define MCLGET(m, how) \
250 { MCLALLOC((m)->m_ext.ext_buf, (how)); \
251 if ((m)->m_ext.ext_buf != NULL) { \
252 (m)->m_data = (m)->m_ext.ext_buf; \
253 (m)->m_flags |= M_EXT; \
254 (m)->m_ext.ext_free = NULL; \
255 (m)->m_ext.ext_ref = NULL; \
256 (m)->m_ext.ext_size = MCLBYTES; \
262 if (--mclrefcnt[mtocl(p)] == 0) { \
263 ((union mcluster *)(p))->mcl_next = mclfree; \
264 mclfree = (union mcluster *)(p); \
270 * MFREE(struct mbuf *m, struct mbuf *n)
271 * Free a single mbuf and associated external storage.
272 * Place the successor, if any, in n.
274 #define MFREE(m, n) \
276 mbstat.m_mtypes[(m)->m_type]--; \
277 if ((m)->m_flags & M_EXT) { \
278 if ((m)->m_ext.ext_free) \
279 (*((m)->m_ext.ext_free))((m)->m_ext.ext_buf, \
280 (m)->m_ext.ext_size); \
282 char *p = (m)->m_ext.ext_buf; \
283 if (--mclrefcnt[mtocl(p)] == 0) { \
284 ((union mcluster *)(p))->mcl_next = mclfree; \
285 mclfree = (union mcluster *)(p); \
291 (m)->m_type = MT_FREE; \
292 mbstat.m_mtypes[MT_FREE]++; \
293 (m)->m_next = mmbfree; \
298 * Copy mbuf pkthdr from from to to.
299 * from must have M_PKTHDR set, and to must be empty.
301 #define M_COPY_PKTHDR(to, from) { \
302 (to)->m_pkthdr = (from)->m_pkthdr; \
303 (to)->m_flags = (from)->m_flags & M_COPYFLAGS; \
304 (to)->m_data = (to)->m_pktdat; \
308 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
309 * an object of the specified size at the end of the mbuf, longword aligned.
311 #define M_ALIGN(m, len) \
312 { (m)->m_data += (MLEN - (len)) &~ (sizeof(long) - 1); }
314 * As above, for mbufs allocated with m_gethdr/MGETHDR
315 * or initialized by M_COPY_PKTHDR.
317 #define MH_ALIGN(m, len) \
318 { (m)->m_data += (MHLEN - (len)) &~ (sizeof(long) - 1); }
321 * Compute the amount of space available
322 * before the current start of data in an mbuf.
324 #define M_LEADINGSPACE(m) \
325 ((m)->m_flags & M_EXT ? /* (m)->m_data - (m)->m_ext.ext_buf */ 0 : \
326 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \
327 (m)->m_data - (m)->m_dat)
330 * Compute the amount of space available
331 * after the end of data in an mbuf.
333 #define M_TRAILINGSPACE(m) \
334 ((m)->m_flags & M_EXT ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size - \
335 ((m)->m_data + (m)->m_len) : \
336 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
339 * Arrange to prepend space of size plen to mbuf m.
340 * If a new mbuf must be allocated, how specifies whether to wait.
341 * If how is M_DONTWAIT and allocation fails, the original mbuf chain
342 * is freed and m is set to NULL.
344 #define M_PREPEND(m, plen, how) { \
345 if (M_LEADINGSPACE(m) >= (plen)) { \
346 (m)->m_data -= (plen); \
347 (m)->m_len += (plen); \
349 (m) = m_prepend((m), (plen), (how)); \
350 if ((m) && (m)->m_flags & M_PKTHDR) \
351 (m)->m_pkthdr.len += (plen); \
354 /* change mbuf to new type */
355 #define MCHTYPE(m, t) do { \
356 MBUFLOCK(mbstat.m_mtypes[(m)->m_type]--; mbstat.m_mtypes[t]++;); \
360 /* length to m_copy to copy all */
361 #define M_COPYALL 1000000000
363 /* compatibility with 4.3 */
364 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT)
370 u_long m_mbufs; /* mbufs obtained from page pool */
371 u_long m_clusters; /* clusters obtained from page pool */
372 u_long m_spare; /* spare field */
373 u_long m_clfree; /* free clusters */
374 u_long m_drops; /* times failed to find space */
375 u_long m_wait; /* times waited for space */
376 u_long m_drain; /* times drained protocols for space */
377 u_short m_mtypes[256]; /* type specific mbuf allocations */
378 u_long m_mcfail; /* times m_copym failed */
379 u_long m_mpfail; /* times m_pullup failed */
380 u_long m_msize; /* length of an mbuf */
381 u_long m_mclbytes; /* length of an mbuf cluster */
382 u_long m_minclsize; /* min length of data to allocate a cluster */
383 u_long m_mlen; /* length of data in an mbuf */
384 u_long m_mhlen; /* length of data in a header mbuf */
388 extern struct mbuf *mbutl; /* virtual address of mclusters */
389 extern char *mclrefcnt; /* cluster reference counts */
390 extern struct mbstat mbstat;
391 extern int nmbclusters;
394 extern struct mbuf *mmbfree;
395 extern union mcluster *mclfree;
396 extern int max_linkhdr; /* largest link-level header */
397 extern int max_protohdr; /* largest protocol header */
398 extern int max_hdr; /* largest link+protocol header */
399 extern int max_datalen; /* MHLEN - max_hdr */
401 struct mbuf *m_copym __P((struct mbuf *, int, int, int));
402 struct mbuf *m_copypacket __P((struct mbuf *, int));
403 struct mbuf *m_devget __P((char *, int, int, struct ifnet *,
404 void (*copy)(char *, caddr_t, u_int)));
405 struct mbuf *m_free __P((struct mbuf *));
406 struct mbuf *m_get __P((int, int));
407 struct mbuf *m_getclr __P((int, int));
408 struct mbuf *m_gethdr __P((int, int));
409 struct mbuf *m_prepend __P((struct mbuf *,int,int));
410 struct mbuf *m_pullup __P((struct mbuf *, int));
411 struct mbuf *m_retry __P((int, int));
412 struct mbuf *m_retryhdr __P((int, int));
413 struct mbuf *m_split __P((struct mbuf *,int,int));
414 void m_adj __P((struct mbuf *, int));
415 void m_cat __P((struct mbuf *,struct mbuf *));
416 int m_mballoc __P((int, int));
417 int m_clalloc __P((int, int));
418 void m_copyback __P((struct mbuf *, int, int, caddr_t));
419 void m_copydata __P((struct mbuf *,int,int,caddr_t));
420 void m_freem __P((struct mbuf *));
423 #endif /* !_SYS_MBUF_H_ */