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30 * @(#)mbuf.h 8.5 (Berkeley) 2/19/95
37 /* XXX: These includes suck. Sorry! */
38 #include <sys/queue.h>
40 #include <sys/systm.h>
48 * Mbufs are of a single size, MSIZE (sys/param.h), which includes overhead.
49 * An mbuf may add a single "mbuf cluster" of size MCLBYTES (also in
50 * sys/param.h), which has no additional overhead and is used instead of the
51 * internal data area; this is done when at least MINCLSIZE of data must be
52 * stored. Additionally, it is possible to allocate a separate buffer
53 * externally and attach it to the mbuf in a way similar to that of mbuf
56 #define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */
57 #define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */
58 #define MINCLSIZE (MHLEN + 1) /* smallest amount to put in cluster */
59 #define M_MAXCOMPRESS (MHLEN / 2) /* max amount to copy for compression */
63 * Macros for type conversion:
64 * mtod(m, t) -- Convert mbuf pointer to data pointer of correct type.
65 * dtom(x) -- Convert data pointer within mbuf to mbuf pointer (XXX).
67 #define mtod(m, t) ((t)((m)->m_data))
68 #define dtom(x) ((struct mbuf *)((intptr_t)(x) & ~(MSIZE-1)))
71 * Argument structure passed to UMA routines during mbuf and packet
75 int flags; /* Flags for mbuf being allocated */
76 short type; /* Type of mbuf being allocated */
87 * Header present at the beginning of every mbuf.
90 struct mbuf *mh_next; /* next buffer in chain */
91 struct mbuf *mh_nextpkt; /* next chain in queue/record */
92 caddr_t mh_data; /* location of data */
93 int mh_len; /* amount of data in this mbuf */
94 int mh_flags; /* flags; see below */
95 short mh_type; /* type of data in this mbuf */
96 uint8_t pad[M_HDR_PAD];/* word align */
100 * Packet tag structure (see below for details).
103 SLIST_ENTRY(m_tag) m_tag_link; /* List of packet tags */
104 u_int16_t m_tag_id; /* Tag ID */
105 u_int16_t m_tag_len; /* Length of data */
106 u_int32_t m_tag_cookie; /* ABI/Module ID */
107 void (*m_tag_free)(struct m_tag *);
111 * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
114 struct ifnet *rcvif; /* rcv interface */
115 /* variables for ip and tcp reassembly */
116 void *header; /* pointer to packet header */
117 int len; /* total packet length */
118 /* variables for hardware checksum */
119 int csum_flags; /* flags regarding checksum */
120 int csum_data; /* data field used by csum routines */
121 u_int16_t tso_segsz; /* TSO segment size */
122 u_int16_t ether_vtag; /* Ethernet 802.1p+q vlan tag */
123 SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
127 * Description of external storage mapped into mbuf; valid only if M_EXT is
131 caddr_t ext_buf; /* start of buffer */
132 void (*ext_free) /* free routine if not the usual */
134 void *ext_arg1; /* optional argument pointer */
135 void *ext_arg2; /* optional argument pointer */
136 u_int ext_size; /* size of buffer, for ext_free */
137 volatile u_int *ref_cnt; /* pointer to ref count info */
138 int ext_type; /* type of external storage */
142 * The core of the mbuf object along with some shortcut defines for practical
149 struct pkthdr MH_pkthdr; /* M_PKTHDR set */
151 struct m_ext MH_ext; /* M_EXT set */
152 char MH_databuf[MHLEN];
155 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */
158 #define m_next m_hdr.mh_next
159 #define m_len m_hdr.mh_len
160 #define m_data m_hdr.mh_data
161 #define m_type m_hdr.mh_type
162 #define m_flags m_hdr.mh_flags
163 #define m_nextpkt m_hdr.mh_nextpkt
164 #define m_act m_nextpkt
165 #define m_pkthdr M_dat.MH.MH_pkthdr
166 #define m_ext M_dat.MH.MH_dat.MH_ext
167 #define m_pktdat M_dat.MH.MH_dat.MH_databuf
168 #define m_dat M_dat.M_databuf
173 #define M_EXT 0x00000001 /* has associated external storage */
174 #define M_PKTHDR 0x00000002 /* start of record */
175 #define M_EOR 0x00000004 /* end of record */
176 #define M_RDONLY 0x00000008 /* associated data is marked read-only */
177 #define M_PROTO1 0x00000010 /* protocol-specific */
178 #define M_PROTO2 0x00000020 /* protocol-specific */
179 #define M_PROTO3 0x00000040 /* protocol-specific */
180 #define M_PROTO4 0x00000080 /* protocol-specific */
181 #define M_PROTO5 0x00000100 /* protocol-specific */
182 #define M_BCAST 0x00000200 /* send/received as link-level broadcast */
183 #define M_MCAST 0x00000400 /* send/received as link-level multicast */
184 #define M_FRAG 0x00000800 /* packet is a fragment of a larger packet */
185 #define M_FIRSTFRAG 0x00001000 /* packet is first fragment */
186 #define M_LASTFRAG 0x00002000 /* packet is last fragment */
187 #define M_SKIP_FIREWALL 0x00004000 /* skip firewall processing */
188 #define M_FREELIST 0x00008000 /* mbuf is on the free list */
189 #define M_VLANTAG 0x00010000 /* ether_vtag is valid */
190 #define M_PROMISC 0x00020000 /* packet was not for us */
191 #define M_NOFREE 0x00040000 /* do not free mbuf, embedded in cluster */
192 #define M_PROTO6 0x00080000 /* protocol-specific */
193 #define M_PROTO7 0x00100000 /* protocol-specific */
194 #define M_PROTO8 0x00200000 /* protocol-specific */
196 #define M_NOTIFICATION M_PROTO5 /* SCTP notification */
199 * Flags to purge when crossing layers.
201 #define M_PROTOFLAGS \
202 (M_PROTO1|M_PROTO2|M_PROTO3|M_PROTO4|M_PROTO5|M_PROTO6|M_PROTO7|M_PROTO8)
205 * Flags preserved when copying m_pkthdr.
207 #define M_COPYFLAGS \
208 (M_PKTHDR|M_EOR|M_RDONLY|M_PROTOFLAGS|M_SKIP_FIREWALL|M_BCAST|M_MCAST|\
209 M_FRAG|M_FIRSTFRAG|M_LASTFRAG|M_VLANTAG|M_PROMISC)
212 * External buffer types: identify ext_buf type.
214 #define EXT_CLUSTER 1 /* mbuf cluster */
215 #define EXT_SFBUF 2 /* sendfile(2)'s sf_bufs */
216 #define EXT_JUMBOP 3 /* jumbo cluster 4096 bytes */
217 #define EXT_JUMBO9 4 /* jumbo cluster 9216 bytes */
218 #define EXT_JUMBO16 5 /* jumbo cluster 16184 bytes */
219 #define EXT_PACKET 6 /* mbuf+cluster from packet zone */
220 #define EXT_MBUF 7 /* external mbuf reference (M_IOVEC) */
221 #define EXT_NET_DRV 100 /* custom ext_buf provided by net driver(s) */
222 #define EXT_MOD_TYPE 200 /* custom module's ext_buf type */
223 #define EXT_DISPOSABLE 300 /* can throw this buffer away w/page flipping */
224 #define EXT_EXTREF 400 /* has externally maintained ref_cnt ptr */
227 * Flags indicating hw checksum support and sw checksum requirements. This
228 * field can be directly tested against if_data.ifi_hwassist.
230 #define CSUM_IP 0x0001 /* will csum IP */
231 #define CSUM_TCP 0x0002 /* will csum TCP */
232 #define CSUM_UDP 0x0004 /* will csum UDP */
233 #define CSUM_IP_FRAGS 0x0008 /* will csum IP fragments */
234 #define CSUM_FRAGMENT 0x0010 /* will do IP fragmentation */
235 #define CSUM_TSO 0x0020 /* will do TSO */
237 #define CSUM_IP_CHECKED 0x0100 /* did csum IP */
238 #define CSUM_IP_VALID 0x0200 /* ... the csum is valid */
239 #define CSUM_DATA_VALID 0x0400 /* csum_data field is valid */
240 #define CSUM_PSEUDO_HDR 0x0800 /* csum_data has pseudo hdr */
242 #define CSUM_DELAY_DATA (CSUM_TCP | CSUM_UDP)
243 #define CSUM_DELAY_IP (CSUM_IP) /* XXX add ipv6 here too? */
248 #define MT_NOTMBUF 0 /* USED INTERNALLY ONLY! Object is not mbuf */
249 #define MT_DATA 1 /* dynamic (data) allocation */
250 #define MT_HEADER MT_DATA /* packet header, use M_PKTHDR instead */
251 #define MT_SONAME 8 /* socket name */
252 #define MT_CONTROL 14 /* extra-data protocol message */
253 #define MT_OOBDATA 15 /* expedited data */
254 #define MT_NTYPES 16 /* number of mbuf types for mbtypes[] */
256 #define MT_NOINIT 255 /* Not a type but a flag to allocate
257 a non-initialized mbuf */
259 #define MB_NOTAGS 0x1UL /* no tags attached to mbuf */
262 * General mbuf allocator statistics structure.
264 * Many of these statistics are no longer used; we instead track many
265 * allocator statistics through UMA's built in statistics mechanism.
268 u_long m_mbufs; /* XXX */
269 u_long m_mclusts; /* XXX */
271 u_long m_drain; /* times drained protocols for space */
272 u_long m_mcfail; /* XXX: times m_copym failed */
273 u_long m_mpfail; /* XXX: times m_pullup failed */
274 u_long m_msize; /* length of an mbuf */
275 u_long m_mclbytes; /* length of an mbuf cluster */
276 u_long m_minclsize; /* min length of data to allocate a cluster */
277 u_long m_mlen; /* length of data in an mbuf */
278 u_long m_mhlen; /* length of data in a header mbuf */
280 /* Number of mbtypes (gives # elems in mbtypes[] array: */
283 /* XXX: Sendfile stats should eventually move to their own struct */
284 u_long sf_iocnt; /* times sendfile had to do disk I/O */
285 u_long sf_allocfail; /* times sfbuf allocation failed */
286 u_long sf_allocwait; /* times sfbuf allocation had to wait */
290 * Flags specifying how an allocation should be made.
292 * The flag to use is as follows:
293 * - M_DONTWAIT or M_NOWAIT from an interrupt handler to not block allocation.
294 * - M_WAIT or M_WAITOK from wherever it is safe to block.
296 * M_DONTWAIT/M_NOWAIT means that we will not block the thread explicitly and
297 * if we cannot allocate immediately we may return NULL, whereas
298 * M_WAIT/M_WAITOK means that if we cannot allocate resources we
299 * will block until they are available, and thus never return NULL.
301 * XXX Eventually just phase this out to use M_WAITOK/M_NOWAIT.
303 #define MBTOM(how) (how)
304 #define M_DONTWAIT M_NOWAIT
305 #define M_TRYWAIT M_WAITOK
306 #define M_WAIT M_WAITOK
309 * String names of mbuf-related UMA(9) and malloc(9) types. Exposed to
310 * !_KERNEL so that monitoring tools can look up the zones with
313 #define MBUF_MEM_NAME "mbuf"
314 #define MBUF_CLUSTER_MEM_NAME "mbuf_cluster"
315 #define MBUF_PACKET_MEM_NAME "mbuf_packet"
316 #define MBUF_JUMBOP_MEM_NAME "mbuf_jumbo_page"
317 #define MBUF_JUMBO9_MEM_NAME "mbuf_jumbo_9k"
318 #define MBUF_JUMBO16_MEM_NAME "mbuf_jumbo_16k"
319 #define MBUF_TAG_MEM_NAME "mbuf_tag"
320 #define MBUF_EXTREFCNT_MEM_NAME "mbuf_ext_refcnt"
325 #define MBUF_CHECKSLEEP(how) do { \
326 if (how == M_WAITOK) \
327 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, \
328 "Sleeping in \"%s\"", __func__); \
331 #define MBUF_CHECKSLEEP(how)
335 * Network buffer allocation API
337 * The rest of it is defined in kern/kern_mbuf.c
340 extern uma_zone_t zone_mbuf;
341 extern uma_zone_t zone_clust;
342 extern uma_zone_t zone_pack;
343 extern uma_zone_t zone_jumbop;
344 extern uma_zone_t zone_jumbo9;
345 extern uma_zone_t zone_jumbo16;
346 extern uma_zone_t zone_ext_refcnt;
348 static __inline struct mbuf *m_getcl(int how, short type, int flags);
349 static __inline struct mbuf *m_get(int how, short type);
350 static __inline struct mbuf *m_gethdr(int how, short type);
351 static __inline struct mbuf *m_getjcl(int how, short type, int flags,
353 static __inline struct mbuf *m_getclr(int how, short type); /* XXX */
354 static __inline struct mbuf *m_free(struct mbuf *m);
355 static __inline void m_clget(struct mbuf *m, int how);
356 static __inline void *m_cljget(struct mbuf *m, int how, int size);
357 static __inline void m_chtype(struct mbuf *m, short new_type);
358 void mb_free_ext(struct mbuf *);
359 static __inline struct mbuf *m_last(struct mbuf *m);
373 #if MJUMPAGESIZE != MCLBYTES
385 panic("%s: m_getjcl: invalid cluster size", __func__);
391 static __inline uma_zone_t
403 #if MJUMPAGESIZE != MCLBYTES
415 panic("%s: m_getjcl: invalid cluster type", __func__);
421 static __inline struct mbuf *
422 m_get(int how, short type)
428 return ((struct mbuf *)(uma_zalloc_arg(zone_mbuf, &args, how)));
432 * XXX This should be deprecated, very little use.
434 static __inline struct mbuf *
435 m_getclr(int how, short type)
442 m = uma_zalloc_arg(zone_mbuf, &args, how);
444 bzero(m->m_data, MLEN);
448 static __inline struct mbuf *
449 m_gethdr(int how, short type)
453 args.flags = M_PKTHDR;
455 return ((struct mbuf *)(uma_zalloc_arg(zone_mbuf, &args, how)));
458 static __inline struct mbuf *
459 m_getcl(int how, short type, int flags)
465 return ((struct mbuf *)(uma_zalloc_arg(zone_pack, &args, how)));
469 * m_getjcl() returns an mbuf with a cluster of the specified size attached.
470 * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
472 * XXX: This is rather large, should be real function maybe.
474 static __inline struct mbuf *
475 m_getjcl(int how, short type, int flags, int size)
484 m = uma_zalloc_arg(zone_mbuf, &args, how);
488 zone = m_getzone(size);
489 n = uma_zalloc_arg(zone, m, how);
491 uma_zfree(zone_mbuf, m);
498 m_free_fast(struct mbuf *m)
501 if (m->m_flags & M_PKTHDR)
502 KASSERT(SLIST_EMPTY(&m->m_pkthdr.tags), ("doing fast free of mbuf with tags"));
505 uma_zfree_arg(zone_mbuf, m, (void *)MB_NOTAGS);
508 static __inline struct mbuf *
509 m_free(struct mbuf *m)
511 struct mbuf *n = m->m_next;
513 if (m->m_flags & M_EXT)
515 else if ((m->m_flags & M_NOFREE) == 0)
516 uma_zfree(zone_mbuf, m);
521 m_clget(struct mbuf *m, int how)
524 if (m->m_flags & M_EXT)
525 printf("%s: %p mbuf already has cluster\n", __func__, m);
526 m->m_ext.ext_buf = (char *)NULL;
527 uma_zalloc_arg(zone_clust, m, how);
529 * On a cluster allocation failure, drain the packet zone and retry,
530 * we might be able to loosen a few clusters up on the drain.
532 if ((how & M_NOWAIT) && (m->m_ext.ext_buf == NULL)) {
533 zone_drain(zone_pack);
534 uma_zalloc_arg(zone_clust, m, how);
539 * m_cljget() is different from m_clget() as it can allocate clusters without
540 * attaching them to an mbuf. In that case the return value is the pointer
541 * to the cluster of the requested size. If an mbuf was specified, it gets
542 * the cluster attached to it and the return value can be safely ignored.
543 * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
545 static __inline void *
546 m_cljget(struct mbuf *m, int how, int size)
550 if (m && m->m_flags & M_EXT)
551 printf("%s: %p mbuf already has cluster\n", __func__, m);
553 m->m_ext.ext_buf = NULL;
555 zone = m_getzone(size);
556 return (uma_zalloc_arg(zone, m, how));
560 m_cljset(struct mbuf *m, void *cl, int type)
570 #if MJUMPAGESIZE != MCLBYTES
585 panic("unknown cluster type");
589 m->m_data = m->m_ext.ext_buf = cl;
590 m->m_ext.ext_free = m->m_ext.ext_arg1 = m->m_ext.ext_arg2 = NULL;
591 m->m_ext.ext_size = size;
592 m->m_ext.ext_type = type;
593 m->m_ext.ref_cnt = uma_find_refcnt(zone, cl);
599 m_chtype(struct mbuf *m, short new_type)
602 m->m_type = new_type;
605 static __inline struct mbuf *
606 m_last(struct mbuf *m)
615 * mbuf, cluster, and external object allocation macros (for compatibility
618 #define M_MOVE_PKTHDR(to, from) m_move_pkthdr((to), (from))
619 #define MGET(m, how, type) ((m) = m_get((how), (type)))
620 #define MGETHDR(m, how, type) ((m) = m_gethdr((how), (type)))
621 #define MCLGET(m, how) m_clget((m), (how))
622 #define MEXTADD(m, buf, size, free, arg1, arg2, flags, type) \
623 m_extadd((m), (caddr_t)(buf), (size), (free),(arg1),(arg2),(flags), (type))
624 #define m_getm(m, len, how, type) \
625 m_getm2((m), (len), (how), (type), M_PKTHDR)
628 * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can
629 * be both the local data payload, or an external buffer area, depending on
630 * whether M_EXT is set).
632 #define M_WRITABLE(m) (!((m)->m_flags & M_RDONLY) && \
633 (!(((m)->m_flags & M_EXT)) || \
634 (*((m)->m_ext.ref_cnt) == 1)) ) \
636 /* Check if the supplied mbuf has a packet header, or else panic. */
637 #define M_ASSERTPKTHDR(m) \
638 KASSERT((m) != NULL && (m)->m_flags & M_PKTHDR, \
639 ("%s: no mbuf packet header!", __func__))
642 * Ensure that the supplied mbuf is a valid, non-free mbuf.
644 * XXX: Broken at the moment. Need some UMA magic to make it work again.
646 #define M_ASSERTVALID(m) \
647 KASSERT((((struct mbuf *)m)->m_flags & 0) == 0, \
648 ("%s: attempted use of a free mbuf!", __func__))
651 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place an
652 * object of the specified size at the end of the mbuf, longword aligned.
654 #define M_ALIGN(m, len) do { \
655 KASSERT(!((m)->m_flags & (M_PKTHDR|M_EXT)), \
656 ("%s: M_ALIGN not normal mbuf", __func__)); \
657 KASSERT((m)->m_data == (m)->m_dat, \
658 ("%s: M_ALIGN not a virgin mbuf", __func__)); \
659 (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1); \
663 * As above, for mbufs allocated with m_gethdr/MGETHDR or initialized by
666 #define MH_ALIGN(m, len) do { \
667 KASSERT((m)->m_flags & M_PKTHDR && !((m)->m_flags & M_EXT), \
668 ("%s: MH_ALIGN not PKTHDR mbuf", __func__)); \
669 KASSERT((m)->m_data == (m)->m_pktdat, \
670 ("%s: MH_ALIGN not a virgin mbuf", __func__)); \
671 (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1); \
675 * Compute the amount of space available before the current start of data in
678 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
679 * of checking writability of the mbuf data area rests solely with the caller.
681 #define M_LEADINGSPACE(m) \
682 ((m)->m_flags & M_EXT ? \
683 (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0): \
684 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \
685 (m)->m_data - (m)->m_dat)
688 * Compute the amount of space available after the end of data in an mbuf.
690 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
691 * of checking writability of the mbuf data area rests solely with the caller.
693 #define M_TRAILINGSPACE(m) \
694 ((m)->m_flags & M_EXT ? \
695 (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size \
696 - ((m)->m_data + (m)->m_len) : 0) : \
697 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
700 * Arrange to prepend space of size plen to mbuf m. If a new mbuf must be
701 * allocated, how specifies whether to wait. If the allocation fails, the
702 * original mbuf chain is freed and m is set to NULL.
704 #define M_PREPEND(m, plen, how) do { \
705 struct mbuf **_mmp = &(m); \
706 struct mbuf *_mm = *_mmp; \
707 int _mplen = (plen); \
708 int __mhow = (how); \
710 MBUF_CHECKSLEEP(how); \
711 if (M_LEADINGSPACE(_mm) >= _mplen) { \
712 _mm->m_data -= _mplen; \
713 _mm->m_len += _mplen; \
715 _mm = m_prepend(_mm, _mplen, __mhow); \
716 if (_mm != NULL && _mm->m_flags & M_PKTHDR) \
717 _mm->m_pkthdr.len += _mplen; \
722 * Change mbuf to new type. This is a relatively expensive operation and
725 #define MCHTYPE(m, t) m_chtype((m), (t))
727 /* Length to m_copy to copy all. */
728 #define M_COPYALL 1000000000
730 /* Compatibility with 4.3. */
731 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT)
733 extern int max_datalen; /* MHLEN - max_hdr */
734 extern int max_hdr; /* Largest link + protocol header */
735 extern int max_linkhdr; /* Largest link-level header */
736 extern int max_protohdr; /* Largest protocol header */
737 extern struct mbstat mbstat; /* General mbuf stats/infos */
738 extern int nmbclusters; /* Maximum number of clusters */
742 void m_adj(struct mbuf *, int);
743 void m_align(struct mbuf *, int);
744 int m_apply(struct mbuf *, int, int,
745 int (*)(void *, void *, u_int), void *);
746 int m_append(struct mbuf *, int, c_caddr_t);
747 void m_cat(struct mbuf *, struct mbuf *);
748 void m_extadd(struct mbuf *, caddr_t, u_int,
749 void (*)(void *, void *), void *, void *, int, int);
750 struct mbuf *m_collapse(struct mbuf *, int, int);
751 void m_copyback(struct mbuf *, int, int, c_caddr_t);
752 void m_copydata(const struct mbuf *, int, int, caddr_t);
753 struct mbuf *m_copym(struct mbuf *, int, int, int);
754 struct mbuf *m_copymdata(struct mbuf *, struct mbuf *,
756 struct mbuf *m_copypacket(struct mbuf *, int);
757 void m_copy_pkthdr(struct mbuf *, struct mbuf *);
758 struct mbuf *m_copyup(struct mbuf *n, int len, int dstoff);
759 struct mbuf *m_defrag(struct mbuf *, int);
760 void m_demote(struct mbuf *, int);
761 struct mbuf *m_devget(char *, int, int, struct ifnet *,
762 void (*)(char *, caddr_t, u_int));
763 struct mbuf *m_dup(struct mbuf *, int);
764 int m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
765 u_int m_fixhdr(struct mbuf *);
766 struct mbuf *m_fragment(struct mbuf *, int, int);
767 void m_freem(struct mbuf *);
768 struct mbuf *m_getm2(struct mbuf *, int, int, short, int);
769 struct mbuf *m_getptr(struct mbuf *, int, int *);
770 u_int m_length(struct mbuf *, struct mbuf **);
771 void m_move_pkthdr(struct mbuf *, struct mbuf *);
772 struct mbuf *m_prepend(struct mbuf *, int, int);
773 void m_print(const struct mbuf *, int);
774 struct mbuf *m_pulldown(struct mbuf *, int, int, int *);
775 struct mbuf *m_pullup(struct mbuf *, int);
776 int m_sanity(struct mbuf *, int);
777 struct mbuf *m_split(struct mbuf *, int, int);
778 struct mbuf *m_uiotombuf(struct uio *, int, int, int, int);
779 struct mbuf *m_unshare(struct mbuf *, int how);
782 * Network packets may have annotations attached by affixing a list of
783 * "packet tags" to the pkthdr structure. Packet tags are dynamically
784 * allocated semi-opaque data structures that have a fixed header
785 * (struct m_tag) that specifies the size of the memory block and a
786 * <cookie,type> pair that identifies it. The cookie is a 32-bit unique
787 * unsigned value used to identify a module or ABI. By convention this value
788 * is chosen as the date+time that the module is created, expressed as the
789 * number of seconds since the epoch (e.g., using date -u +'%s'). The type
790 * value is an ABI/module-specific value that identifies a particular
791 * annotation and is private to the module. For compatibility with systems
792 * like OpenBSD that define packet tags w/o an ABI/module cookie, the value
793 * PACKET_ABI_COMPAT is used to implement m_tag_get and m_tag_find
794 * compatibility shim functions and several tag types are defined below.
795 * Users that do not require compatibility should use a private cookie value
796 * so that packet tag-related definitions can be maintained privately.
798 * Note that the packet tag returned by m_tag_alloc has the default memory
799 * alignment implemented by malloc. To reference private data one can use a
802 * struct m_tag *mtag = m_tag_alloc(...);
803 * struct foo *p = (struct foo *)(mtag+1);
805 * if the alignment of struct m_tag is sufficient for referencing members of
806 * struct foo. Otherwise it is necessary to embed struct m_tag within the
807 * private data structure to insure proper alignment; e.g.,
813 * struct foo *p = (struct foo *) m_tag_alloc(...);
814 * struct m_tag *mtag = &p->tag;
818 * Persistent tags stay with an mbuf until the mbuf is reclaimed. Otherwise
819 * tags are expected to ``vanish'' when they pass through a network
820 * interface. For most interfaces this happens normally as the tags are
821 * reclaimed when the mbuf is free'd. However in some special cases
822 * reclaiming must be done manually. An example is packets that pass through
823 * the loopback interface. Also, one must be careful to do this when
824 * ``turning around'' packets (e.g., icmp_reflect).
826 * To mark a tag persistent bit-or this flag in when defining the tag id.
827 * The tag will then be treated as described above.
829 #define MTAG_PERSISTENT 0x800
831 #define PACKET_TAG_NONE 0 /* Nadda */
833 /* Packet tags for use with PACKET_ABI_COMPAT. */
834 #define PACKET_TAG_IPSEC_IN_DONE 1 /* IPsec applied, in */
835 #define PACKET_TAG_IPSEC_OUT_DONE 2 /* IPsec applied, out */
836 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE 3 /* NIC IPsec crypto done */
837 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED 4 /* NIC IPsec crypto req'ed */
838 #define PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO 5 /* NIC notifies IPsec */
839 #define PACKET_TAG_IPSEC_PENDING_TDB 6 /* Reminder to do IPsec */
840 #define PACKET_TAG_BRIDGE 7 /* Bridge processing done */
841 #define PACKET_TAG_GIF 8 /* GIF processing done */
842 #define PACKET_TAG_GRE 9 /* GRE processing done */
843 #define PACKET_TAG_IN_PACKET_CHECKSUM 10 /* NIC checksumming done */
844 #define PACKET_TAG_ENCAP 11 /* Encap. processing */
845 #define PACKET_TAG_IPSEC_SOCKET 12 /* IPSEC socket ref */
846 #define PACKET_TAG_IPSEC_HISTORY 13 /* IPSEC history */
847 #define PACKET_TAG_IPV6_INPUT 14 /* IPV6 input processing */
848 #define PACKET_TAG_DUMMYNET 15 /* dummynet info */
849 #define PACKET_TAG_DIVERT 17 /* divert info */
850 #define PACKET_TAG_IPFORWARD 18 /* ipforward info */
851 #define PACKET_TAG_MACLABEL (19 | MTAG_PERSISTENT) /* MAC label */
852 #define PACKET_TAG_PF 21 /* PF + ALTQ information */
853 #define PACKET_TAG_RTSOCKFAM 25 /* rtsock sa family */
854 #define PACKET_TAG_IPOPTIONS 27 /* Saved IP options */
855 #define PACKET_TAG_CARP 28 /* CARP info */
857 /* Specific cookies and tags. */
859 /* Packet tag routines. */
860 struct m_tag *m_tag_alloc(u_int32_t, int, int, int);
861 void m_tag_delete(struct mbuf *, struct m_tag *);
862 void m_tag_delete_chain(struct mbuf *, struct m_tag *);
863 void m_tag_free_default(struct m_tag *);
864 struct m_tag *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
865 struct m_tag *m_tag_copy(struct m_tag *, int);
866 int m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
867 void m_tag_delete_nonpersistent(struct mbuf *);
870 * Initialize the list of tags associated with an mbuf.
873 m_tag_init(struct mbuf *m)
876 SLIST_INIT(&m->m_pkthdr.tags);
880 * Set up the contents of a tag. Note that this does not fill in the free
881 * method; the caller is expected to do that.
883 * XXX probably should be called m_tag_init, but that was already taken.
886 m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
891 t->m_tag_cookie = cookie;
895 * Reclaim resources associated with a tag.
898 m_tag_free(struct m_tag *t)
905 * Return the first tag associated with an mbuf.
907 static __inline struct m_tag *
908 m_tag_first(struct mbuf *m)
911 return (SLIST_FIRST(&m->m_pkthdr.tags));
915 * Return the next tag in the list of tags associated with an mbuf.
917 static __inline struct m_tag *
918 m_tag_next(struct mbuf *m, struct m_tag *t)
921 return (SLIST_NEXT(t, m_tag_link));
925 * Prepend a tag to the list of tags associated with an mbuf.
928 m_tag_prepend(struct mbuf *m, struct m_tag *t)
931 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
935 * Unlink a tag from the list of tags associated with an mbuf.
938 m_tag_unlink(struct mbuf *m, struct m_tag *t)
941 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
944 /* These are for OpenBSD compatibility. */
945 #define MTAG_ABI_COMPAT 0 /* compatibility ABI */
947 static __inline struct m_tag *
948 m_tag_get(int type, int length, int wait)
950 return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
953 static __inline struct m_tag *
954 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
956 return (SLIST_EMPTY(&m->m_pkthdr.tags) ? (struct m_tag *)NULL :
957 m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
962 #endif /* !_SYS_MBUF_H_ */