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33 * @(#)mbuf.h 8.5 (Berkeley) 2/19/95
34 * $FreeBSD: src/sys/sys/mbuf.h,v 1.44.2.17 2003/04/15 06:15:02 silby Exp $
35 * $DragonFly: src/sys/sys/mbuf.h,v 1.3 2003/07/19 21:09:27 dillon Exp $
41 #include <sys/queue.h>
44 * Mbufs are of a single size, MSIZE (machine/param.h), which
45 * includes overhead. An mbuf may add a single "mbuf cluster" of size
46 * MCLBYTES (also in machine/param.h), which has no additional overhead
47 * and is used instead of the internal data area; this is done when
48 * at least MINCLSIZE of data must be stored.
50 #define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */
51 #define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */
52 #define MINCLSIZE (MHLEN + 1) /* smallest amount to put in cluster */
53 #define M_MAXCOMPRESS (MHLEN / 2) /* max amount to copy for compression */
56 * Macros for type conversion:
57 * mtod(m, t) -- Convert mbuf pointer to data pointer of correct type.
58 * dtom(x) -- Convert data pointer within mbuf to mbuf pointer (XXX).
59 * mtocl(x) - convert pointer within cluster to cluster index #
60 * cltom(x) - convert cluster # to ptr to beginning of cluster
62 #define mtod(m, t) ((t)((m)->m_data))
63 #define dtom(x) ((struct mbuf *)((intptr_t)(x) & ~(MSIZE-1)))
64 #define mtocl(x) (((uintptr_t)(x) - (uintptr_t)mbutl) >> MCLSHIFT)
65 #define cltom(x) ((caddr_t)((uintptr_t)mbutl + \
66 ((uintptr_t)(x) << MCLSHIFT)))
69 * Header present at the beginning of every mbuf.
72 struct mbuf *mh_next; /* next buffer in chain */
73 struct mbuf *mh_nextpkt; /* next chain in queue/record */
74 caddr_t mh_data; /* location of data */
75 int mh_len; /* amount of data in this mbuf */
76 short mh_type; /* type of data in this mbuf */
77 short mh_flags; /* flags; see below */
81 * Packet tag structure (see below for details).
84 SLIST_ENTRY(m_tag) m_tag_link; /* List of packet tags */
85 u_int16_t m_tag_id; /* Tag ID */
86 u_int16_t m_tag_len; /* Length of data */
87 u_int32_t m_tag_cookie; /* ABI/Module ID */
91 * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
94 struct ifnet *rcvif; /* rcv interface */
95 int len; /* total packet length */
96 /* variables for ip and tcp reassembly */
97 void *header; /* pointer to packet header */
98 /* variables for hardware checksum */
99 int csum_flags; /* flags regarding checksum */
100 int csum_data; /* data field used by csum routines */
101 SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
105 * Description of external storage mapped into mbuf; valid only if M_EXT is set.
108 caddr_t ext_buf; /* start of buffer */
109 void (*ext_free) /* free routine if not the usual */
111 u_int ext_size; /* size of buffer, for ext_free */
112 void (*ext_ref) /* add a reference to the ext object */
117 * The core of the mbuf object along with some shortcut defines for
118 * practical purposes.
124 struct pkthdr MH_pkthdr; /* M_PKTHDR set */
126 struct m_ext MH_ext; /* M_EXT set */
127 char MH_databuf[MHLEN];
130 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */
133 #define m_next m_hdr.mh_next
134 #define m_len m_hdr.mh_len
135 #define m_data m_hdr.mh_data
136 #define m_type m_hdr.mh_type
137 #define m_flags m_hdr.mh_flags
138 #define m_nextpkt m_hdr.mh_nextpkt
139 #define m_act m_nextpkt
140 #define m_pkthdr M_dat.MH.MH_pkthdr
141 #define m_ext M_dat.MH.MH_dat.MH_ext
142 #define m_pktdat M_dat.MH.MH_dat.MH_databuf
143 #define m_dat M_dat.M_databuf
148 #define M_EXT 0x0001 /* has associated external storage */
149 #define M_PKTHDR 0x0002 /* start of record */
150 #define M_EOR 0x0004 /* end of record */
151 #define M_PROTO1 0x0008 /* protocol-specific */
152 #define M_PROTO2 0x0010 /* protocol-specific */
153 #define M_PROTO3 0x0020 /* protocol-specific */
154 #define M_PROTO4 0x0040 /* protocol-specific */
155 #define M_PROTO5 0x0080 /* protocol-specific */
158 * mbuf pkthdr flags (also stored in m_flags).
160 #define M_BCAST 0x0100 /* send/received as link-level broadcast */
161 #define M_MCAST 0x0200 /* send/received as link-level multicast */
162 #define M_FRAG 0x0400 /* packet is a fragment of a larger packet */
163 #define M_FIRSTFRAG 0x0800 /* packet is first fragment */
164 #define M_LASTFRAG 0x1000 /* packet is last fragment */
167 * Flags copied when copying m_pkthdr.
169 #define M_COPYFLAGS (M_PKTHDR|M_EOR|M_PROTO1|M_PROTO1|M_PROTO2|M_PROTO3 | \
170 M_PROTO4|M_PROTO5|M_BCAST|M_MCAST|M_FRAG | \
171 M_FIRSTFRAG|M_LASTFRAG)
174 * Flags indicating hw checksum support and sw checksum requirements.
176 #define CSUM_IP 0x0001 /* will csum IP */
177 #define CSUM_TCP 0x0002 /* will csum TCP */
178 #define CSUM_UDP 0x0004 /* will csum UDP */
179 #define CSUM_IP_FRAGS 0x0008 /* will csum IP fragments */
180 #define CSUM_FRAGMENT 0x0010 /* will do IP fragmentation */
182 #define CSUM_IP_CHECKED 0x0100 /* did csum IP */
183 #define CSUM_IP_VALID 0x0200 /* ... the csum is valid */
184 #define CSUM_DATA_VALID 0x0400 /* csum_data field is valid */
185 #define CSUM_PSEUDO_HDR 0x0800 /* csum_data has pseudo hdr */
187 #define CSUM_DELAY_DATA (CSUM_TCP | CSUM_UDP)
188 #define CSUM_DELAY_IP (CSUM_IP) /* XXX add ipv6 here too? */
193 #define MT_FREE 0 /* should be on free list */
194 #define MT_DATA 1 /* dynamic (data) allocation */
195 #define MT_HEADER 2 /* packet header */
197 #define MT_SOCKET 3 /* socket structure */
198 #define MT_PCB 4 /* protocol control block */
199 #define MT_RTABLE 5 /* routing tables */
200 #define MT_HTABLE 6 /* IMP host tables */
201 #define MT_ATABLE 7 /* address resolution tables */
203 #define MT_SONAME 8 /* socket name */
205 #define MT_SOOPTS 10 /* socket options */
207 #define MT_FTABLE 11 /* fragment reassembly header */
209 #define MT_RIGHTS 12 /* access rights */
210 #define MT_IFADDR 13 /* interface address */
212 #define MT_TAG 13 /* volatile metadata associated to pkts */
213 #define MT_CONTROL 14 /* extra-data protocol message */
214 #define MT_OOBDATA 15 /* expedited data */
215 #define MT_NTYPES 16 /* number of mbuf types for mbtypes[] */
218 * General mbuf allocator statistics structure.
221 u_long m_mbufs; /* mbufs obtained from page pool */
222 u_long m_clusters; /* clusters obtained from page pool */
223 u_long m_spare; /* spare field */
224 u_long m_clfree; /* free clusters */
225 u_long m_drops; /* times failed to find space */
226 u_long m_wait; /* times waited for space */
227 u_long m_drain; /* times drained protocols for space */
228 u_long m_mcfail; /* times m_copym failed */
229 u_long m_mpfail; /* times m_pullup failed */
230 u_long m_msize; /* length of an mbuf */
231 u_long m_mclbytes; /* length of an mbuf cluster */
232 u_long m_minclsize; /* min length of data to allocate a cluster */
233 u_long m_mlen; /* length of data in an mbuf */
234 u_long m_mhlen; /* length of data in a header mbuf */
238 * Flags specifying how an allocation should be made.
246 * Normal mbuf clusters are normally treated as character arrays
247 * after allocation, but use the first word of the buffer as a free list
248 * pointer while on the free list.
251 union mcluster *mcl_next;
252 char mcl_buf[MCLBYTES];
257 * These are identifying numbers passed to the m_mballoc_wait function,
258 * allowing us to determine whether the call came from an MGETHDR or
265 * Wake up the next instance (if any) of m_mballoc_wait() which is
266 * waiting for an mbuf to be freed. This should be called at splimp().
268 * XXX: If there is another free mbuf, this routine will be called [again]
269 * from the m_mballoc_wait routine in order to wake another sleep instance.
271 #define MMBWAKEUP() do { \
272 if (m_mballoc_wid) { \
274 wakeup_one(&m_mballoc_wid); \
279 * Same as above, but for mbuf cluster(s).
281 #define MCLWAKEUP() do { \
282 if (m_clalloc_wid) { \
284 wakeup_one(&m_clalloc_wid); \
289 * mbuf utility macros:
292 * prevents a section of code from from being interrupted by network
295 #define MBUFLOCK(code) do { \
296 int _ms = splimp(); \
303 * mbuf allocation/deallocation macros (YYY deprecated, too big):
305 * MGET(struct mbuf *m, int how, int type)
306 * allocates an mbuf and initializes it to contain internal data.
308 * MGETHDR(struct mbuf *m, int how, int type)
309 * allocates an mbuf and initializes it to contain a packet header
312 #define MGET(m, how, type) do { \
313 (m) = m_get((how), (type)); \
316 #define MGETHDR(m, how, type) do { \
317 (m) = m_gethdr((how), (type)); \
321 * Mbuf cluster macros.
322 * MCLALLOC(caddr_t p, int how) allocates an mbuf cluster.
323 * MCLGET adds such clusters to a normal mbuf;
324 * the flag M_EXT is set upon success.
325 * MCLFREE releases a reference to a cluster allocated by MCLALLOC,
326 * freeing the cluster if the reference count has reached 0.
328 #define MCLALLOC(p, how) do { \
331 int _ms = splimp(); \
333 if (mclfree == NULL) \
334 (void)m_clalloc(1, _mhow); \
335 _mp = (caddr_t)mclfree; \
337 mclrefcnt[mtocl(_mp)]++; \
339 mclfree = ((union mcluster *)_mp)->mcl_next; \
344 if (_mhow == M_WAIT) \
345 (p) = m_clalloc_wait(); \
351 #define MCLGET(m, how) do { \
352 struct mbuf *_mm = (m); \
354 MCLALLOC(_mm->m_ext.ext_buf, (how)); \
355 if (_mm->m_ext.ext_buf != NULL) { \
356 _mm->m_data = _mm->m_ext.ext_buf; \
357 _mm->m_flags |= M_EXT; \
358 _mm->m_ext.ext_free = NULL; \
359 _mm->m_ext.ext_ref = NULL; \
360 _mm->m_ext.ext_size = MCLBYTES; \
364 #define MCLFREE1(p) do { \
365 union mcluster *_mp = (union mcluster *)(p); \
367 KASSERT(mclrefcnt[mtocl(_mp)] > 0, ("freeing free cluster")); \
368 if (--mclrefcnt[mtocl(_mp)] == 0) { \
369 _mp->mcl_next = mclfree; \
376 #define MCLFREE(p) MBUFLOCK( \
380 #define MEXTFREE1(m) do { \
381 struct mbuf *_mm = (m); \
383 if (_mm->m_ext.ext_free != NULL) \
384 (*_mm->m_ext.ext_free)(_mm->m_ext.ext_buf, \
385 _mm->m_ext.ext_size); \
387 MCLFREE1(_mm->m_ext.ext_buf); \
390 #define MEXTFREE(m) MBUFLOCK( \
395 * NB: M_COPY_PKTHDR is deprecated; use either M_MOVE_PKTHDR
399 * Move mbuf pkthdr from "from" to "to".
400 * from should have M_PKTHDR set, and to must be empty.
401 * from no longer has a pkthdr after this operation.
403 #define M_MOVE_PKTHDR(_to, _from) m_move_pkthdr((_to), (_from))
406 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
407 * an object of the specified size at the end of the mbuf, longword aligned.
409 #define M_ALIGN(m, len) do { \
410 (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1); \
414 * As above, for mbufs allocated with m_gethdr/MGETHDR
415 * or initialized by M_COPY_PKTHDR.
417 #define MH_ALIGN(m, len) do { \
418 (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1); \
422 * Check if we can write to an mbuf.
424 #define M_EXT_WRITABLE(m) \
425 ((m)->m_ext.ext_free == NULL && mclrefcnt[mtocl((m)->m_ext.ext_buf)] == 1)
427 #define M_WRITABLE(m) (!((m)->m_flags & M_EXT) || \
431 * Compute the amount of space available
432 * before the current start of data in an mbuf.
434 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
435 * of checking writability of the mbuf data area rests solely with the caller.
437 #define M_LEADINGSPACE(m) \
438 ((m)->m_flags & M_EXT ? \
439 (M_EXT_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0): \
440 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \
441 (m)->m_data - (m)->m_dat)
444 * Compute the amount of space available
445 * after the end of data in an mbuf.
447 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
448 * of checking writability of the mbuf data area rests solely with the caller.
450 #define M_TRAILINGSPACE(m) \
451 ((m)->m_flags & M_EXT ? \
452 (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size \
453 - ((m)->m_data + (m)->m_len) : 0) : \
454 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
457 * Arrange to prepend space of size plen to mbuf m.
458 * If a new mbuf must be allocated, how specifies whether to wait.
459 * If how is M_DONTWAIT and allocation fails, the original mbuf chain
460 * is freed and m is set to NULL.
462 #define M_PREPEND(m, plen, how) do { \
463 struct mbuf **_mmp = &(m); \
464 struct mbuf *_mm = *_mmp; \
465 int _mplen = (plen); \
466 int __mhow = (how); \
468 if (M_LEADINGSPACE(_mm) >= _mplen) { \
469 _mm->m_data -= _mplen; \
470 _mm->m_len += _mplen; \
472 _mm = m_prepend(_mm, _mplen, __mhow); \
473 if (_mm != NULL && _mm->m_flags & M_PKTHDR) \
474 _mm->m_pkthdr.len += _mplen; \
478 /* change mbuf to new type */
479 #define MCHTYPE(m, t) do { \
480 struct mbuf *_mm = (m); \
482 int _ms = splimp(); \
484 mbtypes[_mm->m_type]--; \
487 _mm->m_type = (_mt); \
490 /* Length to m_copy to copy all. */
491 #define M_COPYALL 1000000000
493 /* Compatibility with 4.3 */
494 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT)
497 extern u_int m_clalloc_wid; /* mbuf cluster wait count */
498 extern u_int m_mballoc_wid; /* mbuf wait count */
499 extern int max_linkhdr; /* largest link-level header */
500 extern int max_protohdr; /* largest protocol header */
501 extern int max_hdr; /* largest link+protocol header */
502 extern int max_datalen; /* MHLEN - max_hdr */
503 extern struct mbstat mbstat;
504 extern u_long mbtypes[MT_NTYPES]; /* per-type mbuf allocations */
505 extern int mbuf_wait; /* mbuf sleep time */
506 extern struct mbuf *mbutl; /* virtual address of mclusters */
507 extern char *mclrefcnt; /* cluster reference counts */
508 extern union mcluster *mclfree;
509 extern struct mbuf *mmbfree;
510 extern int nmbclusters;
514 void m_adj(struct mbuf *, int);
515 void m_cat(struct mbuf *, struct mbuf *);
516 int m_clalloc(int, int);
517 caddr_t m_clalloc_wait(void);
518 void m_copyback(struct mbuf *, int, int, caddr_t);
519 void m_copydata(struct mbuf *, int, int, caddr_t);
520 struct mbuf *m_copym(struct mbuf *, int, int, int);
521 struct mbuf *m_copypacket(struct mbuf *, int);
522 struct mbuf *m_defrag(struct mbuf *, int);
523 struct mbuf *m_devget(char *, int, int, struct ifnet *,
524 void (*copy)(char *, caddr_t, u_int));
525 struct mbuf *m_dup(struct mbuf *, int);
526 int m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
527 struct mbuf *m_free(struct mbuf *);
528 void m_freem(struct mbuf *);
529 struct mbuf *m_get(int, int);
530 struct mbuf *m_getcl(int how, short type, int flags);
531 struct mbuf *m_getclr(int, int);
532 struct mbuf *m_gethdr(int, int);
533 struct mbuf *m_getm(struct mbuf *, int, int, int);
534 int m_mballoc(int, int);
535 struct mbuf *m_mballoc_wait(int, int);
536 void m_move_pkthdr(struct mbuf *, struct mbuf *);
537 struct mbuf *m_prepend(struct mbuf *, int, int);
538 void m_print(const struct mbuf *m);
539 struct mbuf *m_pulldown(struct mbuf *, int, int, int *);
540 struct mbuf *m_pullup(struct mbuf *, int);
541 struct mbuf *m_retry(int, int);
542 struct mbuf *m_retryhdr(int, int);
543 struct mbuf *m_split(struct mbuf *, int, int);
546 * Packets may have annotations attached by affixing a list
547 * of "packet tags" to the pkthdr structure. Packet tags are
548 * dynamically allocated semi-opaque data structures that have
549 * a fixed header (struct m_tag) that specifies the size of the
550 * memory block and a <cookie,type> pair that identifies it.
551 * The cookie is a 32-bit unique unsigned value used to identify
552 * a module or ABI. By convention this value is chose as the
553 * date+time that the module is created, expressed as the number of
554 * seconds since the epoch (e.g. using date -u +'%s'). The type value
555 * is an ABI/module-specific value that identifies a particular annotation
556 * and is private to the module. For compatibility with systems
557 * like openbsd that define packet tags w/o an ABI/module cookie,
558 * the value PACKET_ABI_COMPAT is used to implement m_tag_get and
559 * m_tag_find compatibility shim functions and several tag types are
560 * defined below. Users that do not require compatibility should use
561 * a private cookie value so that packet tag-related definitions
562 * can be maintained privately.
564 * Note that the packet tag returned by m_tag_allocate has the default
565 * memory alignment implemented by malloc. To reference private data
566 * one can use a construct like:
568 * struct m_tag *mtag = m_tag_allocate(...);
569 * struct foo *p = (struct foo *)(mtag+1);
571 * if the alignment of struct m_tag is sufficient for referencing members
572 * of struct foo. Otherwise it is necessary to embed struct m_tag within
573 * the private data structure to insure proper alignment; e.g.
579 * struct foo *p = (struct foo *) m_tag_allocate(...);
580 * struct m_tag *mtag = &p->tag;
583 #define PACKET_TAG_NONE 0 /* Nadda */
585 /* Packet tag for use with PACKET_ABI_COMPAT */
586 #define PACKET_TAG_IPSEC_IN_DONE 1 /* IPsec applied, in */
587 #define PACKET_TAG_IPSEC_OUT_DONE 2 /* IPsec applied, out */
588 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE 3 /* NIC IPsec crypto done */
589 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED 4 /* NIC IPsec crypto req'ed */
590 #define PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO 5 /* NIC notifies IPsec */
591 #define PACKET_TAG_IPSEC_PENDING_TDB 6 /* Reminder to do IPsec */
592 #define PACKET_TAG_BRIDGE 7 /* Bridge processing done */
593 #define PACKET_TAG_GIF 8 /* GIF processing done */
594 #define PACKET_TAG_GRE 9 /* GRE processing done */
595 #define PACKET_TAG_IN_PACKET_CHECKSUM 10 /* NIC checksumming done */
596 #define PACKET_TAG_ENCAP 11 /* Encap. processing */
597 #define PACKET_TAG_IPSEC_SOCKET 12 /* IPSEC socket ref */
598 #define PACKET_TAG_IPSEC_HISTORY 13 /* IPSEC history */
599 #define PACKET_TAG_IPV6_INPUT 14 /* IPV6 input processing */
602 * As a temporary and low impact solution to replace the even uglier
603 * approach used so far in some parts of the network stack (which relies
604 * on global variables), packet tag-like annotations are stored in MT_TAG
605 * mbufs (or lookalikes) prepended to the actual mbuf chain.
609 * m_next = next buffer in chain.
611 * BE VERY CAREFUL not to pass these blocks to the mbuf handling routines.
613 #define _m_tag_id m_hdr.mh_flags
615 /* Packet tags used in the FreeBSD network stack */
616 #define PACKET_TAG_DUMMYNET 15 /* dummynet info */
617 #define PACKET_TAG_IPFW 16 /* ipfw classification */
618 #define PACKET_TAG_DIVERT 17 /* divert info */
619 #define PACKET_TAG_IPFORWARD 18 /* ipforward info */
621 /* Packet tag routines */
622 struct m_tag *m_tag_alloc(u_int32_t, int, int, int);
623 void m_tag_free(struct m_tag *);
624 void m_tag_prepend(struct mbuf *, struct m_tag *);
625 void m_tag_unlink(struct mbuf *, struct m_tag *);
626 void m_tag_delete(struct mbuf *, struct m_tag *);
627 void m_tag_delete_chain(struct mbuf *, struct m_tag *);
628 struct m_tag *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
629 struct m_tag *m_tag_copy(struct m_tag *, int);
630 int m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
631 void m_tag_init(struct mbuf *);
632 struct m_tag *m_tag_first(struct mbuf *);
633 struct m_tag *m_tag_next(struct mbuf *, struct m_tag *);
635 /* these are for openbsd compatibility */
636 #define MTAG_ABI_COMPAT 0 /* compatibility ABI */
638 static __inline struct m_tag *
639 m_tag_get(int type, int length, int wait)
641 return m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait);
644 static __inline struct m_tag *
645 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
647 return m_tag_locate(m, MTAG_ABI_COMPAT, type, start);
651 #endif /* !_SYS_MBUF_H_ */