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35 * @(#)mbuf.h 8.5 (Berkeley) 2/19/95
36 * $FreeBSD: src/sys/sys/mbuf.h,v 1.44.2.17 2003/04/15 06:15:02 silby Exp $
37 * $DragonFly: src/sys/sys/mbuf.h,v 1.23 2005/04/18 14:26:57 joerg Exp $
43 #include <sys/queue.h>
46 * Mbufs are of a single size, MSIZE (machine/param.h), which
47 * includes overhead. An mbuf may add a single "mbuf cluster" of size
48 * MCLBYTES (also in machine/param.h), which has no additional overhead
49 * and is used instead of the internal data area; this is done when
50 * at least MINCLSIZE of data must be stored.
52 #define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */
53 #define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */
54 #define MINCLSIZE (MHLEN + 1) /* smallest amount to put in cluster */
55 #define M_MAXCOMPRESS (MHLEN / 2) /* max amount to copy for compression */
58 * Macros for type conversion:
59 * mtod(m, t) -- Convert mbuf pointer to data pointer of correct type.
60 * mtocl(x) - convert pointer within cluster to cluster index #
61 * cltom(x) - convert cluster # to ptr to beginning of cluster
63 #define mtod(m, t) ((t)((m)->m_data))
66 * Header present at the beginning of every 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 */
78 * Packet tag structure (see below for details).
81 SLIST_ENTRY(m_tag) m_tag_link; /* List of packet tags */
82 u_int16_t m_tag_id; /* Tag ID */
83 u_int16_t m_tag_len; /* Length of data */
84 u_int32_t m_tag_cookie; /* ABI/Module ID */
87 SLIST_HEAD(packet_tags, m_tag);
90 * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
92 * Be careful: The fields have been carefully ordered to avoid hidden padding.
93 * Keep this in mind, when adding or removing fields!
96 struct ifnet *rcvif; /* rcv interface */
97 int len; /* total packet length */
98 struct packet_tags tags; /* list of packet tags */
100 /* variables for ip and tcp reassembly */
101 void *header; /* pointer to packet header */
103 /* variables for hardware checksum */
104 int csum_flags; /* flags regarding checksum */
105 int csum_data; /* data field used by csum routines */
108 uint32_t fw_flags; /* flags for PF */
110 /* variables for PF processing */
111 uint16_t pf_tag; /* PF tag id */
112 uint8_t pf_routed; /* PF routing counter */
114 /* variables for ALTQ processing */
115 uint8_t ecn_af; /* address family for ECN */
116 uint32_t altq_qid; /* queue id */
120 * Description of external storage mapped into mbuf; valid only if M_EXT is set.
123 caddr_t ext_buf; /* start of buffer */
125 void (*old)(caddr_t, u_int);
126 void (*new)(void *arg);
129 u_int ext_size; /* size of buffer, for ext_nfree */
131 void (*old)(caddr_t, u_int);
132 void (*new)(void *arg);
139 * The core of the mbuf object along with some shortcut defines for
140 * practical purposes.
146 struct pkthdr MH_pkthdr; /* M_PKTHDR set */
148 struct m_ext MH_ext; /* M_EXT set */
149 char MH_databuf[MHLEN];
152 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */
155 #define m_next m_hdr.mh_next
156 #define m_len m_hdr.mh_len
157 #define m_data m_hdr.mh_data
158 #define m_type m_hdr.mh_type
159 #define m_flags m_hdr.mh_flags
160 #define m_nextpkt m_hdr.mh_nextpkt
161 #define m_pkthdr M_dat.MH.MH_pkthdr
162 #define m_ext M_dat.MH.MH_dat.MH_ext
163 #define m_pktdat M_dat.MH.MH_dat.MH_databuf
164 #define m_dat M_dat.M_databuf
167 * Code that uses m_act should be converted to use m_nextpkt
168 * instead; m_act is historical and deprecated.
170 #define m_act m_nextpkt
175 #define M_EXT 0x0001 /* has associated external storage */
176 #define M_PKTHDR 0x0002 /* start of record */
177 #define M_EOR 0x0004 /* end of record */
178 #define M_PROTO1 0x0008 /* protocol-specific */
179 #define M_PROTO2 0x0010 /* protocol-specific */
180 #define M_PROTO3 0x0020 /* protocol-specific */
181 #define M_PROTO4 0x0040 /* protocol-specific */
182 #define M_PROTO5 0x0080 /* protocol-specific */
185 * mbuf pkthdr flags (also stored in m_flags).
187 #define M_BCAST 0x0100 /* send/received as link-level broadcast */
188 #define M_MCAST 0x0200 /* send/received as link-level multicast */
189 #define M_FRAG 0x0400 /* packet is a fragment of a larger packet */
190 #define M_FIRSTFRAG 0x0800 /* packet is first fragment */
191 #define M_LASTFRAG 0x1000 /* packet is last fragment */
192 #define M_EXT_OLD 0x2000 /* new ext function format */
193 #define M_EXT_CLUSTER 0x4000 /* standard cluster else special */
196 * Flags copied when copying m_pkthdr.
198 #define M_COPYFLAGS (M_PKTHDR|M_EOR|M_PROTO1|M_PROTO1|M_PROTO2|M_PROTO3 | \
199 M_PROTO4|M_PROTO5|M_BCAST|M_MCAST|M_FRAG | \
200 M_FIRSTFRAG|M_LASTFRAG)
203 * Flags indicating hw checksum support and sw checksum requirements.
205 #define CSUM_IP 0x0001 /* will csum IP */
206 #define CSUM_TCP 0x0002 /* will csum TCP */
207 #define CSUM_UDP 0x0004 /* will csum UDP */
208 #define CSUM_IP_FRAGS 0x0008 /* will csum IP fragments */
209 #define CSUM_FRAGMENT 0x0010 /* will do IP fragmentation */
211 #define CSUM_IP_CHECKED 0x0100 /* did csum IP */
212 #define CSUM_IP_VALID 0x0200 /* ... the csum is valid */
213 #define CSUM_DATA_VALID 0x0400 /* csum_data field is valid */
214 #define CSUM_PSEUDO_HDR 0x0800 /* csum_data has pseudo hdr */
216 #define CSUM_DELAY_DATA (CSUM_TCP | CSUM_UDP)
217 #define CSUM_DELAY_IP (CSUM_IP) /* XXX add ipv6 here too? */
220 * Flags indicating PF processing status
222 #define PF_MBUF_GENERATED 0x00000001
223 #define PF_MBUF_TAGGED 0x00000002 /* pf_tag field is valid */
224 #define PF_MBUF_ROUTED 0x00000004 /* pf_routed field is valid */
225 #define PF_MBUF_TRANSLATE_LOCALHOST \
227 #define PF_MBUF_FRAGCACHE 0x00000010
228 #define ALTQ_MBUF_TAGGED 0x00000020 /* altq_qid is valid */
233 #define MT_FREE 0 /* should be on free list */
234 #define MT_DATA 1 /* dynamic (data) allocation */
235 #define MT_HEADER 2 /* packet header */
236 #define MT_SONAME 3 /* socket name */
237 #define MT_TAG 4 /* volatile metadata associated to pkts */
238 #define MT_CONTROL 5 /* extra-data protocol message */
239 #define MT_OOBDATA 6 /* expedited data */
240 #define MT_NTYPES 7 /* number of mbuf types for mbtypes[] */
243 * General mbuf allocator statistics structure.
246 u_long m_mbufs; /* mbufs obtained from page pool */
247 u_long m_clusters; /* clusters obtained from page pool */
248 u_long m_spare; /* spare field */
249 u_long m_clfree; /* free clusters */
250 u_long m_drops; /* times failed to find space */
251 u_long m_wait; /* times waited for space */
252 u_long m_drain; /* times drained protocols for space */
253 u_long m_mcfail; /* times m_copym failed */
254 u_long m_mpfail; /* times m_pullup failed */
255 u_long m_msize; /* length of an mbuf */
256 u_long m_mclbytes; /* length of an mbuf cluster */
257 u_long m_minclsize; /* min length of data to allocate a cluster */
258 u_long m_mlen; /* length of data in an mbuf */
259 u_long m_mhlen; /* length of data in a header mbuf */
263 * Flags specifying how an allocation should be made.
266 #define MB_DONTWAIT 0x4
267 #define MB_TRYWAIT 0x8
268 #define MB_WAIT MB_TRYWAIT
271 * Mbuf to Malloc Flag Conversion.
273 #define MBTOM(how) ((how) & MB_TRYWAIT ? M_WAITOK : M_NOWAIT)
276 * These are identifying numbers passed to the m_mballoc_wait function,
277 * allowing us to determine whether the call came from an MGETHDR or
284 * Wake up the next instance (if any) of m_mballoc_wait() which is
285 * waiting for an mbuf to be freed. This should be called at splimp().
287 * XXX: If there is another free mbuf, this routine will be called [again]
288 * from the m_mballoc_wait routine in order to wake another sleep instance.
290 #define MMBWAKEUP() do { \
291 if (m_mballoc_wid) { \
293 wakeup_one(&m_mballoc_wid); \
298 * Same as above, but for mbuf cluster(s).
300 #define MCLWAKEUP() do { \
301 if (m_clalloc_wid) { \
303 wakeup_one(&m_clalloc_wid); \
308 * mbuf utility macros:
311 * prevents a section of code from from being interrupted by network
314 #define MBUFLOCK(code) do { \
315 int _ms = splimp(); \
322 * mbuf allocation/deallocation macros (YYY deprecated, too big):
324 * MGET(struct mbuf *m, int how, int type)
325 * allocates an mbuf and initializes it to contain internal data.
327 * MGETHDR(struct mbuf *m, int how, int type)
328 * allocates an mbuf and initializes it to contain a packet header
331 #define MGET(m, how, type) do { \
332 (m) = m_get((how), (type)); \
335 #define MGETHDR(m, how, type) do { \
336 (m) = m_gethdr((how), (type)); \
340 * MCLGET adds such clusters to a normal mbuf. The flag M_EXT is set upon
343 #define MCLGET(m, how) do { \
344 m_mclget((m), (how)); \
348 * NB: M_COPY_PKTHDR is deprecated; use either M_MOVE_PKTHDR
352 * Move mbuf pkthdr from "from" to "to".
353 * from should have M_PKTHDR set, and to must be empty.
354 * from no longer has a pkthdr after this operation.
356 #define M_MOVE_PKTHDR(_to, _from) m_move_pkthdr((_to), (_from))
359 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
360 * an object of the specified size at the end of the mbuf, longword aligned.
362 #define M_ALIGN(m, len) do { \
363 (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1); \
367 * As above, for mbufs allocated with m_gethdr/MGETHDR
368 * or initialized by M_COPY_PKTHDR.
370 #define MH_ALIGN(m, len) do { \
371 (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1); \
375 * Check if we can write to an mbuf.
377 #define M_EXT_WRITABLE(m) (m_sharecount(m) == 1)
378 #define M_WRITABLE(m) (!((m)->m_flags & M_EXT) || M_EXT_WRITABLE(m))
381 * Check if the supplied mbuf has a packet header, or else panic.
383 #define M_ASSERTPKTHDR(m) \
384 KASSERT(m != NULL && m->m_flags & M_PKTHDR, \
385 ("%s: invalid mbuf or no mbuf packet header!", __func__))
388 * Compute the amount of space available
389 * before the current start of data in an mbuf.
391 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
392 * of checking writability of the mbuf data area rests solely with the caller.
394 #define M_LEADINGSPACE(m) \
395 ((m)->m_flags & M_EXT ? \
396 (M_EXT_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0): \
397 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \
398 (m)->m_data - (m)->m_dat)
401 * Compute the amount of space available
402 * after the end of data in an mbuf.
404 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
405 * of checking writability of the mbuf data area rests solely with the caller.
407 #define M_TRAILINGSPACE(m) \
408 ((m)->m_flags & M_EXT ? \
409 (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size \
410 - ((m)->m_data + (m)->m_len) : 0) : \
411 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
414 * Arrange to prepend space of size plen to mbuf m.
415 * If a new mbuf must be allocated, how specifies whether to wait.
416 * If how is MB_DONTWAIT and allocation fails, the original mbuf chain
417 * is freed and m is set to NULL.
419 #define M_PREPEND(m, plen, how) do { \
420 struct mbuf **_mmp = &(m); \
421 struct mbuf *_mm = *_mmp; \
422 int _mplen = (plen); \
423 int __mhow = (how); \
425 if (M_LEADINGSPACE(_mm) >= _mplen) { \
426 _mm->m_data -= _mplen; \
427 _mm->m_len += _mplen; \
429 _mm = m_prepend(_mm, _mplen, __mhow); \
430 if (_mm != NULL && _mm->m_flags & M_PKTHDR) \
431 _mm->m_pkthdr.len += _mplen; \
435 /* Length to m_copy to copy all. */
436 #define M_COPYALL 1000000000
438 /* Compatibility with 4.3 */
439 #define m_copy(m, o, l) m_copym((m), (o), (l), MB_DONTWAIT)
442 extern u_int m_clalloc_wid; /* mbuf cluster wait count */
443 extern u_int m_mballoc_wid; /* mbuf wait count */
444 extern int max_linkhdr; /* largest link-level header */
445 extern int max_protohdr; /* largest protocol header */
446 extern int max_hdr; /* largest link+protocol header */
447 extern int max_datalen; /* MHLEN - max_hdr */
448 extern struct mbstat mbstat;
449 extern int mbuf_wait; /* mbuf sleep time */
450 extern int nmbclusters;
455 void m_adj(struct mbuf *, int);
456 void m_cat(struct mbuf *, struct mbuf *);
457 void m_copyback(struct mbuf *, int, int, caddr_t);
458 void m_copydata(const struct mbuf *, int, int, caddr_t);
459 struct mbuf *m_copym(const struct mbuf *, int, int, int);
460 struct mbuf *m_copypacket(struct mbuf *, int);
461 struct mbuf *m_defrag(struct mbuf *, int);
462 struct mbuf *m_defrag_nofree(struct mbuf *, int);
463 struct mbuf *m_devget(char *, int, int, struct ifnet *,
464 void (*copy)(char *, caddr_t, u_int));
465 struct mbuf *m_dup(struct mbuf *, int);
466 int m_dup_pkthdr(struct mbuf *, const struct mbuf *, int);
467 struct mbuf *m_free(struct mbuf *);
468 void m_freem(struct mbuf *);
469 struct mbuf *m_get(int, int);
470 struct mbuf *m_getcl(int how, short type, int flags);
471 struct mbuf *m_getclr(int, int);
472 struct mbuf *m_gethdr(int, int);
473 struct mbuf *m_getm(struct mbuf *, int, int, int);
474 void m_move_pkthdr(struct mbuf *, struct mbuf *);
475 struct mbuf *m_prepend(struct mbuf *, int, int);
476 void m_print(const struct mbuf *m);
477 struct mbuf *m_pulldown(struct mbuf *, int, int, int *);
478 struct mbuf *m_pullup(struct mbuf *, int);
479 struct mbuf *m_retry(int, int);
480 struct mbuf *m_retryhdr(int, int);
481 struct mbuf *m_split(struct mbuf *, int, int);
482 struct mbuf *m_uiomove(struct uio *, int, int);
483 void m_mclget(struct mbuf *m, int how);
484 int m_sharecount(struct mbuf *m);
485 void m_chtype(struct mbuf *m, int type);
489 * Packets may have annotations attached by affixing a list
490 * of "packet tags" to the pkthdr structure. Packet tags are
491 * dynamically allocated semi-opaque data structures that have
492 * a fixed header (struct m_tag) that specifies the size of the
493 * memory block and a <cookie,type> pair that identifies it.
494 * The cookie is a 32-bit unique unsigned value used to identify
495 * a module or ABI. By convention this value is chose as the
496 * date+time that the module is created, expressed as the number of
497 * seconds since the epoch (e.g. using date -u +'%s'). The type value
498 * is an ABI/module-specific value that identifies a particular annotation
499 * and is private to the module. For compatibility with systems
500 * like openbsd that define packet tags w/o an ABI/module cookie,
501 * the value PACKET_ABI_COMPAT is used to implement m_tag_get and
502 * m_tag_find compatibility shim functions and several tag types are
503 * defined below. Users that do not require compatibility should use
504 * a private cookie value so that packet tag-related definitions
505 * can be maintained privately.
507 * Note that the packet tag returned by m_tag_allocate has the default
508 * memory alignment implemented by malloc. To reference private data
509 * one can use a construct like:
511 * struct m_tag *mtag = m_tag_allocate(...);
512 * struct foo *p = (struct foo *)(mtag+1);
514 * if the alignment of struct m_tag is sufficient for referencing members
515 * of struct foo. Otherwise it is necessary to embed struct m_tag within
516 * the private data structure to insure proper alignment; e.g.
522 * struct foo *p = (struct foo *) m_tag_allocate(...);
523 * struct m_tag *mtag = &p->tag;
526 #define PACKET_TAG_NONE 0 /* Nadda */
528 /* Packet tag for use with PACKET_ABI_COMPAT */
529 #define PACKET_TAG_IPSEC_IN_DONE 1 /* IPsec applied, in */
530 /* struct tdb_indent */
531 #define PACKET_TAG_IPSEC_OUT_DONE 2 /* IPsec applied, out */
532 /* struct tdb_indent */
533 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE 3 /* NIC IPsec crypto done */
534 /* struct tdb_indent, never added */
535 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED 4 /* NIC IPsec crypto req'ed */
536 /* struct tdb_indent, never added */
537 #define PACKET_TAG_IPSEC_PENDING_TDB 5 /* Reminder to do IPsec */
538 /* struct tdb_indent, never added */
539 #define PACKET_TAG_ENCAP 6 /* Encap. processing */
540 /* struct ifnet *, the GIF interface */
541 #define PACKET_TAG_IPSEC_HISTORY 7 /* IPSEC history */
542 /* struct ipsec_history */
543 #define PACKET_TAG_IPV6_INPUT 8 /* IPV6 input processing */
545 #define PACKET_TAG_IPFW_DIVERT 9 /* divert info */
549 * As a temporary and low impact solution to replace the even uglier
550 * approach used so far in some parts of the network stack (which relies
551 * on global variables), packet tag-like annotations are stored in MT_TAG
552 * mbufs (or lookalikes) prepended to the actual mbuf chain.
556 * m_next = next buffer in chain.
558 * BE VERY CAREFUL not to pass these blocks to the mbuf handling routines.
560 #define _m_tag_id m_hdr.mh_flags
562 /* Packet tags used in the FreeBSD network stack */
563 #define PACKET_TAG_DUMMYNET 15 /* dummynet info */
564 /* struct dn_pkt as fake mbuf */
565 #define PACKET_TAG_IPFORWARD 18 /* ipforward info */
566 /* struct sockaddr_in * as m_data */
568 /* Packet tag routines */
569 struct m_tag *m_tag_alloc(u_int32_t, int, int, int);
570 void m_tag_free(struct m_tag *);
571 void m_tag_prepend(struct mbuf *, struct m_tag *);
572 void m_tag_unlink(struct mbuf *, struct m_tag *);
573 void m_tag_delete(struct mbuf *, struct m_tag *);
574 void m_tag_delete_chain(struct mbuf *, struct m_tag *);
575 struct m_tag *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
576 struct m_tag *m_tag_copy(struct m_tag *, int);
577 int m_tag_copy_chain(struct mbuf *, const struct mbuf *, int);
578 void m_tag_init(struct mbuf *);
579 struct m_tag *m_tag_first(struct mbuf *);
580 struct m_tag *m_tag_next(struct mbuf *, struct m_tag *);
582 /* these are for openbsd compatibility */
583 #define MTAG_ABI_COMPAT 0 /* compatibility ABI */
585 static __inline struct m_tag *
586 m_tag_get(int type, int length, int wait)
588 return m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait);
591 static __inline struct m_tag *
592 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
594 return m_tag_locate(m, MTAG_ABI_COMPAT, type, start);
598 #endif /* !_SYS_MBUF_H_ */