FreeBSD/Linux Kernel Cross Reference
sys/sys/mbuf.h
1 /*-
2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)mbuf.h 8.5 (Berkeley) 2/19/95
30 * $FreeBSD: releng/5.3/sys/sys/mbuf.h 136588 2004-10-16 08:43:07Z cvs2svn $
31 */
32
33 #ifndef _SYS_MBUF_H_
34 #define _SYS_MBUF_H_
35
36 /* XXX: These includes suck. Sorry! */
37 #include <sys/queue.h>
38 #ifdef _KERNEL
39 #include <sys/systm.h>
40 #include <vm/uma.h>
41 #ifdef WITNESS
42 #include <sys/lock.h>
43 #endif
44 #endif
45
46 /*
47 * Mbufs are of a single size, MSIZE (sys/param.h), which
48 * includes overhead. An mbuf may add a single "mbuf cluster" of size
49 * MCLBYTES (also in sys/param.h), which has no additional overhead
50 * and is used instead of the internal data area; this is done when
51 * at least MINCLSIZE of data must be stored. Additionally, it is possible
52 * to allocate a separate buffer externally and attach it to the mbuf in
53 * a way similar to that of mbuf clusters.
54 */
55 #define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */
56 #define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */
57 #define MINCLSIZE (MHLEN + 1) /* smallest amount to put in cluster */
58 #define M_MAXCOMPRESS (MHLEN / 2) /* max amount to copy for compression */
59
60 #ifdef _KERNEL
61 /*-
62 * Macros for type conversion:
63 * mtod(m, t) -- Convert mbuf pointer to data pointer of correct type.
64 * dtom(x) -- Convert data pointer within mbuf to mbuf pointer (XXX).
65 */
66 #define mtod(m, t) ((t)((m)->m_data))
67 #define dtom(x) ((struct mbuf *)((intptr_t)(x) & ~(MSIZE-1)))
68
69 /*
70 * Argument structure passed to UMA routines during mbuf and packet
71 * allocations.
72 */
73 struct mb_args {
74 int flags; /* Flags for mbuf being allocated */
75 short type; /* Type of mbuf being allocated */
76 };
77 #endif /* _KERNEL */
78
79 /*
80 * Header present at the beginning of every mbuf.
81 */
82 struct m_hdr {
83 struct mbuf *mh_next; /* next buffer in chain */
84 struct mbuf *mh_nextpkt; /* next chain in queue/record */
85 caddr_t mh_data; /* location of data */
86 int mh_len; /* amount of data in this mbuf */
87 int mh_flags; /* flags; see below */
88 short mh_type; /* type of data in this mbuf */
89 };
90
91 /*
92 * Packet tag structure (see below for details).
93 */
94 struct m_tag {
95 SLIST_ENTRY(m_tag) m_tag_link; /* List of packet tags */
96 u_int16_t m_tag_id; /* Tag ID */
97 u_int16_t m_tag_len; /* Length of data */
98 u_int32_t m_tag_cookie; /* ABI/Module ID */
99 void (*m_tag_free)(struct m_tag *);
100 };
101
102 /*
103 * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
104 */
105 struct pkthdr {
106 struct ifnet *rcvif; /* rcv interface */
107 int len; /* total packet length */
108 /* variables for ip and tcp reassembly */
109 void *header; /* pointer to packet header */
110 /* variables for hardware checksum */
111 int csum_flags; /* flags regarding checksum */
112 int csum_data; /* data field used by csum routines */
113 SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
114 };
115
116 /*
117 * Description of external storage mapped into mbuf; valid only if M_EXT is set.
118 */
119 struct m_ext {
120 caddr_t ext_buf; /* start of buffer */
121 void (*ext_free) /* free routine if not the usual */
122 (void *, void *);
123 void *ext_args; /* optional argument pointer */
124 u_int ext_size; /* size of buffer, for ext_free */
125 u_int *ref_cnt; /* pointer to ref count info */
126 int ext_type; /* type of external storage */
127 };
128
129 /*
130 * The core of the mbuf object along with some shortcut defines for
131 * practical purposes.
132 */
133 struct mbuf {
134 struct m_hdr m_hdr;
135 union {
136 struct {
137 struct pkthdr MH_pkthdr; /* M_PKTHDR set */
138 union {
139 struct m_ext MH_ext; /* M_EXT set */
140 char MH_databuf[MHLEN];
141 } MH_dat;
142 } MH;
143 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */
144 } M_dat;
145 };
146 #define m_next m_hdr.mh_next
147 #define m_len m_hdr.mh_len
148 #define m_data m_hdr.mh_data
149 #define m_type m_hdr.mh_type
150 #define m_flags m_hdr.mh_flags
151 #define m_nextpkt m_hdr.mh_nextpkt
152 #define m_act m_nextpkt
153 #define m_pkthdr M_dat.MH.MH_pkthdr
154 #define m_ext M_dat.MH.MH_dat.MH_ext
155 #define m_pktdat M_dat.MH.MH_dat.MH_databuf
156 #define m_dat M_dat.M_databuf
157
158 /*
159 * mbuf flags.
160 */
161 #define M_EXT 0x0001 /* has associated external storage */
162 #define M_PKTHDR 0x0002 /* start of record */
163 #define M_EOR 0x0004 /* end of record */
164 #define M_RDONLY 0x0008 /* associated data is marked read-only */
165 #define M_PROTO1 0x0010 /* protocol-specific */
166 #define M_PROTO2 0x0020 /* protocol-specific */
167 #define M_PROTO3 0x0040 /* protocol-specific */
168 #define M_PROTO4 0x0080 /* protocol-specific */
169 #define M_PROTO5 0x0100 /* protocol-specific */
170 #define M_SKIP_FIREWALL 0x4000 /* skip firewall processing */
171 #define M_FREELIST 0x8000 /* mbuf is on the free list */
172
173 /*
174 * mbuf pkthdr flags (also stored in m_flags).
175 */
176 #define M_BCAST 0x0200 /* send/received as link-level broadcast */
177 #define M_MCAST 0x0400 /* send/received as link-level multicast */
178 #define M_FRAG 0x0800 /* packet is a fragment of a larger packet */
179 #define M_FIRSTFRAG 0x1000 /* packet is first fragment */
180 #define M_LASTFRAG 0x2000 /* packet is last fragment */
181
182 /*
183 * External buffer types: identify ext_buf type.
184 */
185 #define EXT_CLUSTER 1 /* mbuf cluster */
186 #define EXT_SFBUF 2 /* sendfile(2)'s sf_bufs */
187 #define EXT_PACKET 3 /* came out of Packet zone */
188 #define EXT_NET_DRV 100 /* custom ext_buf provided by net driver(s) */
189 #define EXT_MOD_TYPE 200 /* custom module's ext_buf type */
190 #define EXT_DISPOSABLE 300 /* can throw this buffer away w/page flipping */
191 #define EXT_EXTREF 400 /* has externally maintained ref_cnt ptr */
192
193 /*
194 * Flags copied when copying m_pkthdr.
195 */
196 #define M_COPYFLAGS (M_PKTHDR|M_EOR|M_RDONLY|M_PROTO1|M_PROTO1|M_PROTO2|\
197 M_PROTO3|M_PROTO4|M_PROTO5|M_SKIP_FIREWALL|\
198 M_BCAST|M_MCAST|M_FRAG|M_FIRSTFRAG|M_LASTFRAG)
199
200 /*
201 * Flags indicating hw checksum support and sw checksum requirements.
202 */
203 #define CSUM_IP 0x0001 /* will csum IP */
204 #define CSUM_TCP 0x0002 /* will csum TCP */
205 #define CSUM_UDP 0x0004 /* will csum UDP */
206 #define CSUM_IP_FRAGS 0x0008 /* will csum IP fragments */
207 #define CSUM_FRAGMENT 0x0010 /* will do IP fragmentation */
208
209 #define CSUM_IP_CHECKED 0x0100 /* did csum IP */
210 #define CSUM_IP_VALID 0x0200 /* ... the csum is valid */
211 #define CSUM_DATA_VALID 0x0400 /* csum_data field is valid */
212 #define CSUM_PSEUDO_HDR 0x0800 /* csum_data has pseudo hdr */
213
214 #define CSUM_DELAY_DATA (CSUM_TCP | CSUM_UDP)
215 #define CSUM_DELAY_IP (CSUM_IP) /* XXX add ipv6 here too? */
216
217 /*
218 * mbuf types.
219 */
220 #define MT_NOTMBUF 0 /* USED INTERNALLY ONLY! Object is not mbuf */
221 #define MT_DATA 1 /* dynamic (data) allocation */
222 #define MT_HEADER 2 /* packet header */
223 #if 0
224 #define MT_SOCKET 3 /* socket structure */
225 #define MT_PCB 4 /* protocol control block */
226 #define MT_RTABLE 5 /* routing tables */
227 #define MT_HTABLE 6 /* IMP host tables */
228 #define MT_ATABLE 7 /* address resolution tables */
229 #endif
230 #define MT_SONAME 8 /* socket name */
231 #if 0
232 #define MT_SOOPTS 10 /* socket options */
233 #endif
234 #define MT_FTABLE 11 /* fragment reassembly header */
235 #if 0
236 #define MT_RIGHTS 12 /* access rights */
237 #define MT_IFADDR 13 /* interface address */
238 #endif
239 #define MT_CONTROL 14 /* extra-data protocol message */
240 #define MT_OOBDATA 15 /* expedited data */
241 #define MT_NTYPES 16 /* number of mbuf types for mbtypes[] */
242
243 /*
244 * General mbuf allocator statistics structure.
245 */
246 struct mbstat {
247 u_long m_mbufs; /* XXX */
248 u_long m_mclusts; /* XXX */
249
250 u_long m_drain; /* times drained protocols for space */
251 u_long m_mcfail; /* XXX: times m_copym failed */
252 u_long m_mpfail; /* XXX: times m_pullup failed */
253 u_long m_msize; /* length of an mbuf */
254 u_long m_mclbytes; /* length of an mbuf cluster */
255 u_long m_minclsize; /* min length of data to allocate a cluster */
256 u_long m_mlen; /* length of data in an mbuf */
257 u_long m_mhlen; /* length of data in a header mbuf */
258
259 /* Number of mbtypes (gives # elems in mbtypes[] array: */
260 short m_numtypes;
261
262 /* XXX: Sendfile stats should eventually move to their own struct */
263 u_long sf_iocnt; /* times sendfile had to do disk I/O */
264 u_long sf_allocfail; /* times sfbuf allocation failed */
265 u_long sf_allocwait; /* times sfbuf allocation had to wait */
266 };
267
268 /*
269 * Flags specifying how an allocation should be made.
270 *
271 * The flag to use is as follows:
272 * - M_DONTWAIT or M_NOWAIT from an interrupt handler to not block allocation.
273 * - M_WAIT or M_WAITOK or M_TRYWAIT from wherever it is safe to block.
274 *
275 * M_DONTWAIT/M_NOWAIT means that we will not block the thread explicitly
276 * and if we cannot allocate immediately we may return NULL,
277 * whereas M_WAIT/M_WAITOK/M_TRYWAIT means that if we cannot allocate
278 * resources we will block until they are available, and thus never
279 * return NULL.
280 *
281 * XXX Eventually just phase this out to use M_WAITOK/M_NOWAIT.
282 */
283 #define MBTOM(how) (how)
284 #define M_DONTWAIT M_NOWAIT
285 #define M_TRYWAIT M_WAITOK
286 #define M_WAIT M_WAITOK
287
288 #ifdef _KERNEL
289 /*-
290 * mbuf external reference count management macros.
291 *
292 * MEXT_IS_REF(m): true if (m) is not the only mbuf referencing
293 * the external buffer ext_buf.
294 *
295 * MEXT_REM_REF(m): remove reference to m_ext object.
296 *
297 * MEXT_ADD_REF(m): add reference to m_ext object already
298 * referred to by (m).
299 */
300 #define MEXT_IS_REF(m) (*((m)->m_ext.ref_cnt) > 1)
301
302 #define MEXT_REM_REF(m) do { \
303 KASSERT(*((m)->m_ext.ref_cnt) > 0, ("m_ext refcnt < 0")); \
304 atomic_subtract_int((m)->m_ext.ref_cnt, 1); \
305 } while(0)
306
307 #define MEXT_ADD_REF(m) atomic_add_int((m)->m_ext.ref_cnt, 1)
308
309 #ifdef WITNESS
310 #define MBUF_CHECKSLEEP(how) do { \
311 if (how == M_WAITOK) \
312 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, \
313 "Sleeping in \"%s\"", __func__); \
314 } while(0)
315 #else
316 #define MBUF_CHECKSLEEP(how)
317 #endif
318
319 /*
320 * Network buffer allocation API
321 *
322 * The rest of it is defined in kern/subr_mbuf.c
323 */
324
325 extern uma_zone_t zone_mbuf;
326 extern uma_zone_t zone_clust;
327 extern uma_zone_t zone_pack;
328
329 static __inline struct mbuf *m_get(int how, short type);
330 static __inline struct mbuf *m_gethdr(int how, short type);
331 static __inline struct mbuf *m_getcl(int how, short type, int flags);
332 static __inline struct mbuf *m_getclr(int how, short type); /* XXX */
333 static __inline struct mbuf *m_free(struct mbuf *m);
334 static __inline void m_clget(struct mbuf *m, int how);
335 static __inline void m_chtype(struct mbuf *m, short new_type);
336 void mb_free_ext(struct mbuf *);
337
338 static __inline
339 struct mbuf *
340 m_get(int how, short type)
341 {
342 struct mb_args args;
343
344 args.flags = 0;
345 args.type = type;
346 return (uma_zalloc_arg(zone_mbuf, &args, how));
347 }
348
349 /* XXX This should be depracated, very little use */
350 static __inline
351 struct mbuf *
352 m_getclr(int how, short type)
353 {
354 struct mbuf *m;
355 struct mb_args args;
356
357 args.flags = 0;
358 args.type = type;
359 m = uma_zalloc_arg(zone_mbuf, &args, how);
360 if (m != NULL)
361 bzero(m->m_data, MLEN);
362 return m;
363 }
364
365 static __inline
366 struct mbuf *
367 m_gethdr(int how, short type)
368 {
369 struct mb_args args;
370
371 args.flags = M_PKTHDR;
372 args.type = type;
373 return (uma_zalloc_arg(zone_mbuf, &args, how));
374 }
375
376 static __inline
377 struct mbuf *
378 m_getcl(int how, short type, int flags)
379 {
380 struct mb_args args;
381
382 args.flags = flags;
383 args.type = type;
384 return (uma_zalloc_arg(zone_pack, &args, how));
385 }
386
387 static __inline
388 struct mbuf *
389 m_free(struct mbuf *m)
390 {
391 struct mbuf *n = m->m_next;
392
393 #ifdef INVARIANTS
394 m->m_flags |= M_FREELIST;
395 #endif
396 if (m->m_flags & M_EXT)
397 mb_free_ext(m);
398 else
399 uma_zfree(zone_mbuf, m);
400 return n;
401 }
402
403 static __inline
404 void
405 m_clget(struct mbuf *m, int how)
406 {
407
408 m->m_ext.ext_buf = NULL;
409 uma_zalloc_arg(zone_clust, m, how);
410 }
411
412 static __inline
413 void
414 m_chtype(struct mbuf *m, short new_type)
415 {
416 m->m_type = new_type;
417 }
418
419 /*
420 * mbuf, cluster, and external object allocation macros
421 * (for compatibility purposes).
422 */
423 /* NB: M_COPY_PKTHDR is deprecated. Use M_MOVE_PKTHDR or m_dup_pktdr. */
424 #define M_MOVE_PKTHDR(to, from) m_move_pkthdr((to), (from))
425 #define MGET(m, how, type) ((m) = m_get((how), (type)))
426 #define MGETHDR(m, how, type) ((m) = m_gethdr((how), (type)))
427 #define MCLGET(m, how) m_clget((m), (how))
428 #define MEXTADD(m, buf, size, free, args, flags, type) \
429 m_extadd((m), (caddr_t)(buf), (size), (free), (args), (flags), (type))
430
431 /*
432 * Evaluate TRUE if it's safe to write to the mbuf m's data region (this
433 * can be both the local data payload, or an external buffer area,
434 * depending on whether M_EXT is set).
435 */
436 #define M_WRITABLE(m) (!((m)->m_flags & M_RDONLY) && (!((m)->m_flags \
437 & M_EXT) || !MEXT_IS_REF(m)))
438
439 /* Check if the supplied mbuf has a packet header, or else panic. */
440 #define M_ASSERTPKTHDR(m) \
441 KASSERT(m != NULL && m->m_flags & M_PKTHDR, \
442 ("%s: no mbuf packet header!", __func__))
443
444 /* Ensure that the supplied mbuf is a valid, non-free mbuf. */
445 #define M_ASSERTVALID(m) \
446 KASSERT((((struct mbuf *)m)->m_flags & M_FREELIST) == 0, \
447 ("%s: attempted use of a free mbuf!", __func__))
448
449 /*
450 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
451 * an object of the specified size at the end of the mbuf, longword aligned.
452 */
453 #define M_ALIGN(m, len) do { \
454 (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1); \
455 } while (0)
456
457 /*
458 * As above, for mbufs allocated with m_gethdr/MGETHDR
459 * or initialized by M_COPY_PKTHDR.
460 */
461 #define MH_ALIGN(m, len) do { \
462 (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1); \
463 } while (0)
464
465 /*
466 * Compute the amount of space available
467 * before the current start of data in an mbuf.
468 *
469 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
470 * of checking writability of the mbuf data area rests solely with the caller.
471 */
472 #define M_LEADINGSPACE(m) \
473 ((m)->m_flags & M_EXT ? \
474 (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0): \
475 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \
476 (m)->m_data - (m)->m_dat)
477
478 /*
479 * Compute the amount of space available
480 * after the end of data in an mbuf.
481 *
482 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
483 * of checking writability of the mbuf data area rests solely with the caller.
484 */
485 #define M_TRAILINGSPACE(m) \
486 ((m)->m_flags & M_EXT ? \
487 (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size \
488 - ((m)->m_data + (m)->m_len) : 0) : \
489 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
490
491 /*
492 * Arrange to prepend space of size plen to mbuf m.
493 * If a new mbuf must be allocated, how specifies whether to wait.
494 * If the allocation fails, the original mbuf chain is freed and m is
495 * set to NULL.
496 */
497 #define M_PREPEND(m, plen, how) do { \
498 struct mbuf **_mmp = &(m); \
499 struct mbuf *_mm = *_mmp; \
500 int _mplen = (plen); \
501 int __mhow = (how); \
502 \
503 MBUF_CHECKSLEEP(how); \
504 if (M_LEADINGSPACE(_mm) >= _mplen) { \
505 _mm->m_data -= _mplen; \
506 _mm->m_len += _mplen; \
507 } else \
508 _mm = m_prepend(_mm, _mplen, __mhow); \
509 if (_mm != NULL && _mm->m_flags & M_PKTHDR) \
510 _mm->m_pkthdr.len += _mplen; \
511 *_mmp = _mm; \
512 } while (0)
513
514 /*
515 * Change mbuf to new type.
516 * This is a relatively expensive operation and should be avoided.
517 */
518 #define MCHTYPE(m, t) m_chtype((m), (t))
519
520 /* Length to m_copy to copy all. */
521 #define M_COPYALL 1000000000
522
523 /* Compatibility with 4.3. */
524 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT)
525
526 extern int max_datalen; /* MHLEN - max_hdr */
527 extern int max_hdr; /* Largest link + protocol header */
528 extern int max_linkhdr; /* Largest link-level header */
529 extern int max_protohdr; /* Largest protocol header */
530 extern struct mbstat mbstat; /* General mbuf stats/infos */
531 extern int nmbclusters; /* Maximum number of clusters */
532
533 struct uio;
534
535 void m_adj(struct mbuf *, int);
536 int m_apply(struct mbuf *, int, int,
537 int (*)(void *, void *, u_int), void *);
538 void m_cat(struct mbuf *, struct mbuf *);
539 void m_extadd(struct mbuf *, caddr_t, u_int,
540 void (*)(void *, void *), void *, int, int);
541 void m_copyback(struct mbuf *, int, int, c_caddr_t);
542 void m_copydata(const struct mbuf *, int, int, caddr_t);
543 struct mbuf *m_copym(struct mbuf *, int, int, int);
544 struct mbuf *m_copypacket(struct mbuf *, int);
545 void m_copy_pkthdr(struct mbuf *, struct mbuf *);
546 struct mbuf *m_defrag(struct mbuf *, int);
547 struct mbuf *m_devget(char *, int, int, struct ifnet *,
548 void (*)(char *, caddr_t, u_int));
549 struct mbuf *m_dup(struct mbuf *, int);
550 int m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
551 u_int m_fixhdr(struct mbuf *);
552 struct mbuf *m_fragment(struct mbuf *, int, int);
553 void m_freem(struct mbuf *);
554 struct mbuf *m_getm(struct mbuf *, int, int, short);
555 struct mbuf *m_getptr(struct mbuf *, int, int *);
556 u_int m_length(struct mbuf *, struct mbuf **);
557 void m_move_pkthdr(struct mbuf *, struct mbuf *);
558 struct mbuf *m_prepend(struct mbuf *, int, int);
559 void m_print(const struct mbuf *, int);
560 struct mbuf *m_pulldown(struct mbuf *, int, int, int *);
561 struct mbuf *m_pullup(struct mbuf *, int);
562 struct mbuf *m_split(struct mbuf *, int, int);
563 struct mbuf *m_uiotombuf(struct uio *, int, int);
564
565 /*-
566 * Network packets may have annotations attached by affixing a list
567 * of "packet tags" to the pkthdr structure. Packet tags are
568 * dynamically allocated semi-opaque data structures that have
569 * a fixed header (struct m_tag) that specifies the size of the
570 * memory block and a <cookie,type> pair that identifies it.
571 * The cookie is a 32-bit unique unsigned value used to identify
572 * a module or ABI. By convention this value is chose as the
573 * date+time that the module is created, expressed as the number of
574 * seconds since the epoch (e.g., using date -u +'%s'). The type value
575 * is an ABI/module-specific value that identifies a particular annotation
576 * and is private to the module. For compatibility with systems
577 * like OpenBSD that define packet tags w/o an ABI/module cookie,
578 * the value PACKET_ABI_COMPAT is used to implement m_tag_get and
579 * m_tag_find compatibility shim functions and several tag types are
580 * defined below. Users that do not require compatibility should use
581 * a private cookie value so that packet tag-related definitions
582 * can be maintained privately.
583 *
584 * Note that the packet tag returned by m_tag_alloc has the default
585 * memory alignment implemented by malloc. To reference private data
586 * one can use a construct like:
587 *
588 * struct m_tag *mtag = m_tag_alloc(...);
589 * struct foo *p = (struct foo *)(mtag+1);
590 *
591 * if the alignment of struct m_tag is sufficient for referencing members
592 * of struct foo. Otherwise it is necessary to embed struct m_tag within
593 * the private data structure to insure proper alignment; e.g.,
594 *
595 * struct foo {
596 * struct m_tag tag;
597 * ...
598 * };
599 * struct foo *p = (struct foo *) m_tag_alloc(...);
600 * struct m_tag *mtag = &p->tag;
601 */
602
603 /*
604 * Persistent tags stay with an mbuf until the mbuf is reclaimed.
605 * Otherwise tags are expected to ``vanish'' when they pass through
606 * a network interface. For most interfaces this happens normally
607 * as the tags are reclaimed when the mbuf is free'd. However in
608 * some special cases reclaiming must be done manually. An example
609 * is packets that pass through the loopback interface. Also, one
610 * must be careful to do this when ``turning around'' packets (e.g.,
611 * icmp_reflect).
612 *
613 * To mark a tag persistent bit-or this flag in when defining the
614 * tag id. The tag will then be treated as described above.
615 */
616 #define MTAG_PERSISTENT 0x800
617
618 #define PACKET_TAG_NONE 0 /* Nadda */
619
620 /* Packet tags for use with PACKET_ABI_COMPAT. */
621 #define PACKET_TAG_IPSEC_IN_DONE 1 /* IPsec applied, in */
622 #define PACKET_TAG_IPSEC_OUT_DONE 2 /* IPsec applied, out */
623 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE 3 /* NIC IPsec crypto done */
624 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED 4 /* NIC IPsec crypto req'ed */
625 #define PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO 5 /* NIC notifies IPsec */
626 #define PACKET_TAG_IPSEC_PENDING_TDB 6 /* Reminder to do IPsec */
627 #define PACKET_TAG_BRIDGE 7 /* Bridge processing done */
628 #define PACKET_TAG_GIF 8 /* GIF processing done */
629 #define PACKET_TAG_GRE 9 /* GRE processing done */
630 #define PACKET_TAG_IN_PACKET_CHECKSUM 10 /* NIC checksumming done */
631 #define PACKET_TAG_ENCAP 11 /* Encap. processing */
632 #define PACKET_TAG_IPSEC_SOCKET 12 /* IPSEC socket ref */
633 #define PACKET_TAG_IPSEC_HISTORY 13 /* IPSEC history */
634 #define PACKET_TAG_IPV6_INPUT 14 /* IPV6 input processing */
635 #define PACKET_TAG_DUMMYNET 15 /* dummynet info */
636 #define PACKET_TAG_DIVERT 17 /* divert info */
637 #define PACKET_TAG_IPFORWARD 18 /* ipforward info */
638 #define PACKET_TAG_MACLABEL (19 | MTAG_PERSISTENT) /* MAC label */
639 #define PACKET_TAG_PF_ROUTED 21 /* PF routed, avoid loops */
640 #define PACKET_TAG_PF_FRAGCACHE 22 /* PF fragment cached */
641 #define PACKET_TAG_PF_QID 23 /* PF ALTQ queue id */
642 #define PACKET_TAG_PF_TAG 24 /* PF tagged */
643 #define PACKET_TAG_RTSOCKFAM 25 /* rtsock sa family */
644 #define PACKET_TAG_PF_TRANSLATE_LOCALHOST 26 /* PF translate localhost */
645 #define PACKET_TAG_IPOPTIONS 27 /* Saved IP options */
646
647 /* Packet tag routines. */
648 struct m_tag *m_tag_alloc(u_int32_t, int, int, int);
649 void m_tag_delete(struct mbuf *, struct m_tag *);
650 void m_tag_delete_chain(struct mbuf *, struct m_tag *);
651 struct m_tag *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
652 struct m_tag *m_tag_copy(struct m_tag *, int);
653 int m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
654 void m_tag_delete_nonpersistent(struct mbuf *);
655
656 /*
657 * Initialize the list of tags associated with an mbuf.
658 */
659 static __inline void
660 m_tag_init(struct mbuf *m)
661 {
662 SLIST_INIT(&m->m_pkthdr.tags);
663 }
664
665 /*
666 * Set up the contents of a tag. Note that this does not
667 * fill in the free method; the caller is expected to do that.
668 *
669 * XXX probably should be called m_tag_init, but that was
670 * already taken.
671 */
672 static __inline void
673 m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
674 {
675 t->m_tag_id = type;
676 t->m_tag_len = len;
677 t->m_tag_cookie = cookie;
678 }
679
680 /*
681 * Reclaim resources associated with a tag.
682 */
683 static __inline void
684 m_tag_free(struct m_tag *t)
685 {
686 (*t->m_tag_free)(t);
687 }
688
689 /*
690 * Return the first tag associated with an mbuf.
691 */
692 static __inline struct m_tag *
693 m_tag_first(struct mbuf *m)
694 {
695 return (SLIST_FIRST(&m->m_pkthdr.tags));
696 }
697
698 /*
699 * Return the next tag in the list of tags associated with an mbuf.
700 */
701 static __inline struct m_tag *
702 m_tag_next(struct mbuf *m, struct m_tag *t)
703 {
704 return (SLIST_NEXT(t, m_tag_link));
705 }
706
707 /*
708 * Prepend a tag to the list of tags associated with an mbuf.
709 */
710 static __inline void
711 m_tag_prepend(struct mbuf *m, struct m_tag *t)
712 {
713 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
714 }
715
716 /*
717 * Unlink a tag from the list of tags associated with an mbuf.
718 */
719 static __inline void
720 m_tag_unlink(struct mbuf *m, struct m_tag *t)
721 {
722 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
723 }
724
725 /* These are for OpenBSD compatibility. */
726 #define MTAG_ABI_COMPAT 0 /* compatibility ABI */
727
728 static __inline struct m_tag *
729 m_tag_get(int type, int length, int wait)
730 {
731 return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
732 }
733
734 static __inline struct m_tag *
735 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
736 {
737 return (SLIST_EMPTY(&m->m_pkthdr.tags) ?
738 NULL : m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
739 }
740
741 #endif /* _KERNEL */
742
743 #endif /* !_SYS_MBUF_H_ */
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