xref: /freebsd/sys/sys/mbuf.h (revision ceaec73d406831b1251babb61675df0a1aa54a31)
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  * $FreeBSD$
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 	volatile 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 #define	M_VLANTAG	0x10000	/* packet has VLAN tag attached */
182 
183 /*
184  * External buffer types: identify ext_buf type.
185  */
186 #define	EXT_CLUSTER	1	/* mbuf cluster */
187 #define	EXT_SFBUF	2	/* sendfile(2)'s sf_bufs */
188 #define	EXT_PACKET	3	/* came out of Packet zone */
189 #define	EXT_NET_DRV	100	/* custom ext_buf provided by net driver(s) */
190 #define	EXT_MOD_TYPE	200	/* custom module's ext_buf type */
191 #define	EXT_DISPOSABLE	300	/* can throw this buffer away w/page flipping */
192 #define	EXT_EXTREF	400	/* has externally maintained ref_cnt ptr */
193 
194 /*
195  * Flags copied when copying m_pkthdr.
196  */
197 #define	M_COPYFLAGS	(M_PKTHDR|M_EOR|M_RDONLY|M_PROTO1|M_PROTO1|M_PROTO2|\
198 			    M_PROTO3|M_PROTO4|M_PROTO5|M_SKIP_FIREWALL|\
199 			    M_BCAST|M_MCAST|M_FRAG|M_FIRSTFRAG|M_LASTFRAG|\
200 			    M_VLANTAG)
201 
202 /*
203  * Flags indicating hw checksum support and sw checksum requirements.
204  */
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 */
210 
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 */
215 
216 #define	CSUM_DELAY_DATA		(CSUM_TCP | CSUM_UDP)
217 #define	CSUM_DELAY_IP		(CSUM_IP)	/* XXX add ipv6 here too? */
218 
219 /*
220  * mbuf types.
221  */
222 #define	MT_NOTMBUF	0	/* USED INTERNALLY ONLY! Object is not mbuf */
223 #define	MT_DATA		1	/* dynamic (data) allocation */
224 #define	MT_HEADER	2	/* packet header */
225 #if 0
226 #define	MT_SOCKET	3	/* socket structure */
227 #define	MT_PCB		4	/* protocol control block */
228 #define	MT_RTABLE	5	/* routing tables */
229 #define	MT_HTABLE	6	/* IMP host tables */
230 #define	MT_ATABLE	7	/* address resolution tables */
231 #endif
232 #define	MT_SONAME	8	/* socket name */
233 #if 0
234 #define	MT_SOOPTS	10	/* socket options */
235 #endif
236 #define	MT_FTABLE	11	/* fragment reassembly header */
237 #if 0
238 #define	MT_RIGHTS	12	/* access rights */
239 #define	MT_IFADDR	13	/* interface address */
240 #endif
241 #define	MT_CONTROL	14	/* extra-data protocol message */
242 #define	MT_OOBDATA	15	/* expedited data  */
243 #define	MT_NTYPES	16	/* number of mbuf types for mbtypes[] */
244 
245 /*
246  * General mbuf allocator statistics structure.
247  */
248 struct mbstat {
249 	u_long	m_mbufs;	/* XXX */
250 	u_long	m_mclusts;	/* XXX */
251 
252 	u_long	m_drain;	/* times drained protocols for space */
253 	u_long	m_mcfail;	/* XXX: times m_copym failed */
254 	u_long	m_mpfail;	/* XXX: 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 */
260 
261 	/* Number of mbtypes (gives # elems in mbtypes[] array: */
262 	short	m_numtypes;
263 
264 	/* XXX: Sendfile stats should eventually move to their own struct */
265 	u_long	sf_iocnt;	/* times sendfile had to do disk I/O */
266 	u_long	sf_allocfail;	/* times sfbuf allocation failed */
267 	u_long	sf_allocwait;	/* times sfbuf allocation had to wait */
268 };
269 
270 /*
271  * Flags specifying how an allocation should be made.
272  *
273  * The flag to use is as follows:
274  * - M_DONTWAIT or M_NOWAIT from an interrupt handler to not block allocation.
275  * - M_WAIT or M_WAITOK or M_TRYWAIT from wherever it is safe to block.
276  *
277  * M_DONTWAIT/M_NOWAIT means that we will not block the thread explicitly
278  * and if we cannot allocate immediately we may return NULL,
279  * whereas M_WAIT/M_WAITOK/M_TRYWAIT means that if we cannot allocate
280  * resources we will block until they are available, and thus never
281  * return NULL.
282  *
283  * XXX Eventually just phase this out to use M_WAITOK/M_NOWAIT.
284  */
285 #define	MBTOM(how)	(how)
286 #define	M_DONTWAIT	M_NOWAIT
287 #define	M_TRYWAIT	M_WAITOK
288 #define	M_WAIT		M_WAITOK
289 
290 #ifdef _KERNEL
291 /*-
292  * mbuf external reference count management macros.
293  *
294  * MEXT_IS_REF(m): true if (m) is not the only mbuf referencing
295  *     the external buffer ext_buf.
296  *
297  * MEXT_REM_REF(m): remove reference to m_ext object.
298  *
299  * MEXT_ADD_REF(m): add reference to m_ext object already
300  *     referred to by (m).  XXX Note that it is VERY important that you
301  *     always set the second mbuf's m_ext.ref_cnt to point to the first
302  *     one's (i.e., n->m_ext.ref_cnt = m->m_ext.ref_cnt) AFTER you run
303  *     MEXT_ADD_REF(m).  This is because m might have a lazy initialized
304  *     ref_cnt (NULL) before this is run and it will only be looked up
305  *     from here.  We should make MEXT_ADD_REF() always take two mbufs
306  *     as arguments so that it can take care of this itself.
307  */
308 #define	MEXT_IS_REF(m)	(((m)->m_ext.ref_cnt != NULL)			\
309     && (*((m)->m_ext.ref_cnt) > 1))
310 
311 #define	MEXT_REM_REF(m) do {						\
312 	KASSERT((m)->m_ext.ref_cnt != NULL, ("m_ext refcnt lazy NULL")); \
313 	KASSERT(*((m)->m_ext.ref_cnt) > 0, ("m_ext refcnt < 0"));	\
314 	atomic_subtract_int((m)->m_ext.ref_cnt, 1);			\
315 } while(0)
316 
317 #define	MEXT_ADD_REF(m)	do {						\
318 	if ((m)->m_ext.ref_cnt == NULL) {				\
319 		KASSERT((m)->m_ext.ext_type == EXT_CLUSTER ||		\
320 		    (m)->m_ext.ext_type == EXT_PACKET,			\
321 		    ("Unexpected mbuf type has lazy refcnt"));		\
322 		(m)->m_ext.ref_cnt = (u_int *)uma_find_refcnt(		\
323 		    zone_clust, (m)->m_ext.ext_buf);			\
324 		*((m)->m_ext.ref_cnt) = 2;				\
325 	} else								\
326 		atomic_add_int((m)->m_ext.ref_cnt, 1);			\
327 } while (0)
328 
329 #ifdef WITNESS
330 #define MBUF_CHECKSLEEP(how) do {					\
331 	if (how == M_WAITOK)						\
332 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,		\
333 		    "Sleeping in \"%s\"", __func__);			\
334 } while(0)
335 #else
336 #define MBUF_CHECKSLEEP(how)
337 #endif
338 
339 /*
340  * Network buffer allocation API
341  *
342  * The rest of it is defined in kern/kern_mbuf.c
343  */
344 
345 extern uma_zone_t	zone_mbuf;
346 extern uma_zone_t	zone_clust;
347 extern uma_zone_t	zone_pack;
348 
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_getcl(int how, short type, int flags);
352 static __inline struct mbuf	*m_getclr(int how, short type);	/* XXX */
353 static __inline struct mbuf	*m_free(struct mbuf *m);
354 static __inline void		 m_clget(struct mbuf *m, int how);
355 static __inline void		 m_chtype(struct mbuf *m, short new_type);
356 void				 mb_free_ext(struct mbuf *);
357 
358 static __inline
359 struct mbuf *
360 m_get(int how, short type)
361 {
362 	struct mb_args args;
363 
364 	args.flags = 0;
365 	args.type = type;
366 	return (uma_zalloc_arg(zone_mbuf, &args, how));
367 }
368 
369 /* XXX This should be depracated, very little use */
370 static __inline
371 struct mbuf *
372 m_getclr(int how, short type)
373 {
374 	struct mbuf *m;
375 	struct mb_args args;
376 
377 	args.flags = 0;
378 	args.type = type;
379 	m = uma_zalloc_arg(zone_mbuf, &args, how);
380 	if (m != NULL)
381 		bzero(m->m_data, MLEN);
382 	return m;
383 }
384 
385 static __inline
386 struct mbuf *
387 m_gethdr(int how, short type)
388 {
389 	struct mb_args args;
390 
391 	args.flags = M_PKTHDR;
392 	args.type = type;
393 	return (uma_zalloc_arg(zone_mbuf, &args, how));
394 }
395 
396 static __inline
397 struct mbuf *
398 m_getcl(int how, short type, int flags)
399 {
400 	struct mb_args args;
401 
402 	args.flags = flags;
403 	args.type = type;
404 	return (uma_zalloc_arg(zone_pack, &args, how));
405 }
406 
407 static __inline
408 struct mbuf *
409 m_free(struct mbuf *m)
410 {
411 	struct mbuf *n = m->m_next;
412 
413 #ifdef INVARIANTS
414 	m->m_flags |= M_FREELIST;
415 #endif
416 	if (m->m_flags & M_EXT)
417 		mb_free_ext(m);
418 	else
419 		uma_zfree(zone_mbuf, m);
420 	return n;
421 }
422 
423 static __inline
424 void
425 m_clget(struct mbuf *m, int how)
426 {
427 
428 	m->m_ext.ext_buf = NULL;
429 	uma_zalloc_arg(zone_clust, m, how);
430 }
431 
432 static __inline
433 void
434 m_chtype(struct mbuf *m, short new_type)
435 {
436 	m->m_type = new_type;
437 }
438 
439 /*
440  * mbuf, cluster, and external object allocation macros
441  * (for compatibility purposes).
442  */
443 /* NB: M_COPY_PKTHDR is deprecated.  Use M_MOVE_PKTHDR or m_dup_pktdr. */
444 #define	M_MOVE_PKTHDR(to, from)	m_move_pkthdr((to), (from))
445 #define	MGET(m, how, type)	((m) = m_get((how), (type)))
446 #define	MGETHDR(m, how, type)	((m) = m_gethdr((how), (type)))
447 #define	MCLGET(m, how)		m_clget((m), (how))
448 #define	MEXTADD(m, buf, size, free, args, flags, type) 			\
449     m_extadd((m), (caddr_t)(buf), (size), (free), (args), (flags), (type))
450 
451 /*
452  * Evaluate TRUE if it's safe to write to the mbuf m's data region (this
453  * can be both the local data payload, or an external buffer area,
454  * depending on whether M_EXT is set).
455  */
456 #define	M_WRITABLE(m)	(!((m)->m_flags & M_RDONLY) && (!((m)->m_flags  \
457 			    & M_EXT) || !MEXT_IS_REF(m)))
458 
459 /* Check if the supplied mbuf has a packet header, or else panic. */
460 #define	M_ASSERTPKTHDR(m)						\
461 	KASSERT(m != NULL && m->m_flags & M_PKTHDR,			\
462 	    ("%s: no mbuf packet header!", __func__))
463 
464 /* Ensure that the supplied mbuf is a valid, non-free mbuf. */
465 #define	M_ASSERTVALID(m)						\
466 	KASSERT((((struct mbuf *)m)->m_flags & M_FREELIST) == 0,	\
467 	    ("%s: attempted use of a free mbuf!", __func__))
468 
469 /*
470  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
471  * an object of the specified size at the end of the mbuf, longword aligned.
472  */
473 #define	M_ALIGN(m, len) do {						\
474 	(m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1);		\
475 } while (0)
476 
477 /*
478  * As above, for mbufs allocated with m_gethdr/MGETHDR
479  * or initialized by M_COPY_PKTHDR.
480  */
481 #define	MH_ALIGN(m, len) do {						\
482 	(m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1);		\
483 } while (0)
484 
485 /*
486  * Compute the amount of space available
487  * before the current start of data in an mbuf.
488  *
489  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
490  * of checking writability of the mbuf data area rests solely with the caller.
491  */
492 #define	M_LEADINGSPACE(m)						\
493 	((m)->m_flags & M_EXT ?						\
494 	    (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0):	\
495 	    (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat :	\
496 	    (m)->m_data - (m)->m_dat)
497 
498 /*
499  * Compute the amount of space available
500  * after the end of data in an mbuf.
501  *
502  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
503  * of checking writability of the mbuf data area rests solely with the caller.
504  */
505 #define	M_TRAILINGSPACE(m)						\
506 	((m)->m_flags & M_EXT ?						\
507 	    (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size	\
508 		- ((m)->m_data + (m)->m_len) : 0) :			\
509 	    &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
510 
511 /*
512  * Arrange to prepend space of size plen to mbuf m.
513  * If a new mbuf must be allocated, how specifies whether to wait.
514  * If the allocation fails, the original mbuf chain is freed and m is
515  * set to NULL.
516  */
517 #define	M_PREPEND(m, plen, how) do {					\
518 	struct mbuf **_mmp = &(m);					\
519 	struct mbuf *_mm = *_mmp;					\
520 	int _mplen = (plen);						\
521 	int __mhow = (how);						\
522 									\
523 	MBUF_CHECKSLEEP(how);						\
524 	if (M_LEADINGSPACE(_mm) >= _mplen) {				\
525 		_mm->m_data -= _mplen;					\
526 		_mm->m_len += _mplen;					\
527 	} else								\
528 		_mm = m_prepend(_mm, _mplen, __mhow);			\
529 	if (_mm != NULL && _mm->m_flags & M_PKTHDR)			\
530 		_mm->m_pkthdr.len += _mplen;				\
531 	*_mmp = _mm;							\
532 } while (0)
533 
534 /*
535  * Change mbuf to new type.
536  * This is a relatively expensive operation and should be avoided.
537  */
538 #define	MCHTYPE(m, t)	m_chtype((m), (t))
539 
540 /* Length to m_copy to copy all. */
541 #define	M_COPYALL	1000000000
542 
543 /* Compatibility with 4.3. */
544 #define	m_copy(m, o, l)	m_copym((m), (o), (l), M_DONTWAIT)
545 
546 extern	int max_datalen;		/* MHLEN - max_hdr */
547 extern	int max_hdr;			/* Largest link + protocol header */
548 extern	int max_linkhdr;		/* Largest link-level header */
549 extern	int max_protohdr;		/* Largest protocol header */
550 extern	struct mbstat mbstat;		/* General mbuf stats/infos */
551 extern	int nmbclusters;		/* Maximum number of clusters */
552 
553 struct uio;
554 
555 void		 m_adj(struct mbuf *, int);
556 int		 m_apply(struct mbuf *, int, int,
557 		    int (*)(void *, void *, u_int), void *);
558 int		 m_append(struct mbuf *, int, c_caddr_t);
559 void		 m_cat(struct mbuf *, struct mbuf *);
560 void		 m_extadd(struct mbuf *, caddr_t, u_int,
561 		    void (*)(void *, void *), void *, int, int);
562 void		 m_copyback(struct mbuf *, int, int, c_caddr_t);
563 void		 m_copydata(const struct mbuf *, int, int, caddr_t);
564 struct	mbuf	*m_copym(struct mbuf *, int, int, int);
565 struct	mbuf	*m_copypacket(struct mbuf *, int);
566 void		 m_copy_pkthdr(struct mbuf *, struct mbuf *);
567 struct	mbuf	*m_copyup(struct mbuf *n, int len, int dstoff);
568 struct	mbuf	*m_defrag(struct mbuf *, int);
569 struct	mbuf	*m_devget(char *, int, int, struct ifnet *,
570 		    void (*)(char *, caddr_t, u_int));
571 struct	mbuf	*m_dup(struct mbuf *, int);
572 int		 m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
573 u_int		 m_fixhdr(struct mbuf *);
574 struct	mbuf	*m_fragment(struct mbuf *, int, int);
575 void		 m_freem(struct mbuf *);
576 struct	mbuf	*m_getm(struct mbuf *, int, int, short);
577 struct	mbuf	*m_getptr(struct mbuf *, int, int *);
578 u_int		 m_length(struct mbuf *, struct mbuf **);
579 void		 m_move_pkthdr(struct mbuf *, struct mbuf *);
580 struct	mbuf	*m_prepend(struct mbuf *, int, int);
581 void		 m_print(const struct mbuf *, int);
582 struct	mbuf	*m_pulldown(struct mbuf *, int, int, int *);
583 struct	mbuf	*m_pullup(struct mbuf *, int);
584 struct	mbuf	*m_split(struct mbuf *, int, int);
585 struct	mbuf	*m_uiotombuf(struct uio *, int, int);
586 
587 /*-
588  * Network packets may have annotations attached by affixing a list
589  * of "packet tags" to the pkthdr structure.  Packet tags are
590  * dynamically allocated semi-opaque data structures that have
591  * a fixed header (struct m_tag) that specifies the size of the
592  * memory block and a <cookie,type> pair that identifies it.
593  * The cookie is a 32-bit unique unsigned value used to identify
594  * a module or ABI.  By convention this value is chose as the
595  * date+time that the module is created, expressed as the number of
596  * seconds since the epoch (e.g., using date -u +'%s').  The type value
597  * is an ABI/module-specific value that identifies a particular annotation
598  * and is private to the module.  For compatibility with systems
599  * like OpenBSD that define packet tags w/o an ABI/module cookie,
600  * the value PACKET_ABI_COMPAT is used to implement m_tag_get and
601  * m_tag_find compatibility shim functions and several tag types are
602  * defined below.  Users that do not require compatibility should use
603  * a private cookie value so that packet tag-related definitions
604  * can be maintained privately.
605  *
606  * Note that the packet tag returned by m_tag_alloc has the default
607  * memory alignment implemented by malloc.  To reference private data
608  * one can use a construct like:
609  *
610  *	struct m_tag *mtag = m_tag_alloc(...);
611  *	struct foo *p = (struct foo *)(mtag+1);
612  *
613  * if the alignment of struct m_tag is sufficient for referencing members
614  * of struct foo.  Otherwise it is necessary to embed struct m_tag within
615  * the private data structure to insure proper alignment; e.g.,
616  *
617  *	struct foo {
618  *		struct m_tag	tag;
619  *		...
620  *	};
621  *	struct foo *p = (struct foo *) m_tag_alloc(...);
622  *	struct m_tag *mtag = &p->tag;
623  */
624 
625 /*
626  * Persistent tags stay with an mbuf until the mbuf is reclaimed.
627  * Otherwise tags are expected to ``vanish'' when they pass through
628  * a network interface.  For most interfaces this happens normally
629  * as the tags are reclaimed when the mbuf is free'd.  However in
630  * some special cases reclaiming must be done manually.  An example
631  * is packets that pass through the loopback interface.  Also, one
632  * must be careful to do this when ``turning around'' packets (e.g.,
633  * icmp_reflect).
634  *
635  * To mark a tag persistent bit-or this flag in when defining the
636  * tag id.  The tag will then be treated as described above.
637  */
638 #define	MTAG_PERSISTENT				0x800
639 
640 #define	PACKET_TAG_NONE				0  /* Nadda */
641 
642 /* Packet tags for use with PACKET_ABI_COMPAT. */
643 #define	PACKET_TAG_IPSEC_IN_DONE		1  /* IPsec applied, in */
644 #define	PACKET_TAG_IPSEC_OUT_DONE		2  /* IPsec applied, out */
645 #define	PACKET_TAG_IPSEC_IN_CRYPTO_DONE		3  /* NIC IPsec crypto done */
646 #define	PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED	4  /* NIC IPsec crypto req'ed */
647 #define	PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO	5  /* NIC notifies IPsec */
648 #define	PACKET_TAG_IPSEC_PENDING_TDB		6  /* Reminder to do IPsec */
649 #define	PACKET_TAG_BRIDGE			7  /* Bridge processing done */
650 #define	PACKET_TAG_GIF				8  /* GIF processing done */
651 #define	PACKET_TAG_GRE				9  /* GRE processing done */
652 #define	PACKET_TAG_IN_PACKET_CHECKSUM		10 /* NIC checksumming done */
653 #define	PACKET_TAG_ENCAP			11 /* Encap.  processing */
654 #define	PACKET_TAG_IPSEC_SOCKET			12 /* IPSEC socket ref */
655 #define	PACKET_TAG_IPSEC_HISTORY		13 /* IPSEC history */
656 #define	PACKET_TAG_IPV6_INPUT			14 /* IPV6 input processing */
657 #define	PACKET_TAG_DUMMYNET			15 /* dummynet info */
658 #define	PACKET_TAG_DIVERT			17 /* divert info */
659 #define	PACKET_TAG_IPFORWARD			18 /* ipforward info */
660 #define	PACKET_TAG_MACLABEL	(19 | MTAG_PERSISTENT) /* MAC label */
661 #define	PACKET_TAG_PF_ROUTED			21 /* PF routed, avoid loops */
662 #define	PACKET_TAG_PF_FRAGCACHE			22 /* PF fragment cached */
663 #define	PACKET_TAG_PF_QID			23 /* PF ALTQ queue id */
664 #define	PACKET_TAG_PF_TAG			24 /* PF tagged */
665 #define	PACKET_TAG_RTSOCKFAM			25 /* rtsock sa family */
666 #define	PACKET_TAG_PF_TRANSLATE_LOCALHOST	26 /* PF translate localhost */
667 #define	PACKET_TAG_IPOPTIONS			27 /* Saved IP options */
668 #define	PACKET_TAG_CARP                         28 /* CARP info */
669 
670 /* Packet tag routines. */
671 struct	m_tag	*m_tag_alloc(u_int32_t, int, int, int);
672 void		 m_tag_delete(struct mbuf *, struct m_tag *);
673 void		 m_tag_delete_chain(struct mbuf *, struct m_tag *);
674 void		 m_tag_free_default(struct m_tag *);
675 struct	m_tag	*m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
676 struct	m_tag	*m_tag_copy(struct m_tag *, int);
677 int		 m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
678 void		 m_tag_delete_nonpersistent(struct mbuf *);
679 
680 /*
681  * Initialize the list of tags associated with an mbuf.
682  */
683 static __inline void
684 m_tag_init(struct mbuf *m)
685 {
686 	SLIST_INIT(&m->m_pkthdr.tags);
687 }
688 
689 /*
690  * Set up the contents of a tag.  Note that this does not
691  * fill in the free method; the caller is expected to do that.
692  *
693  * XXX probably should be called m_tag_init, but that was
694  * already taken.
695  */
696 static __inline void
697 m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
698 {
699 	t->m_tag_id = type;
700 	t->m_tag_len = len;
701 	t->m_tag_cookie = cookie;
702 }
703 
704 /*
705  * Reclaim resources associated with a tag.
706  */
707 static __inline void
708 m_tag_free(struct m_tag *t)
709 {
710 	(*t->m_tag_free)(t);
711 }
712 
713 /*
714  * Return the first tag associated with an mbuf.
715  */
716 static __inline struct m_tag *
717 m_tag_first(struct mbuf *m)
718 {
719 	return (SLIST_FIRST(&m->m_pkthdr.tags));
720 }
721 
722 /*
723  * Return the next tag in the list of tags associated with an mbuf.
724  */
725 static __inline struct m_tag *
726 m_tag_next(struct mbuf *m, struct m_tag *t)
727 {
728 	return (SLIST_NEXT(t, m_tag_link));
729 }
730 
731 /*
732  * Prepend a tag to the list of tags associated with an mbuf.
733  */
734 static __inline void
735 m_tag_prepend(struct mbuf *m, struct m_tag *t)
736 {
737 	SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
738 }
739 
740 /*
741  * Unlink a tag from the list of tags associated with an mbuf.
742  */
743 static __inline void
744 m_tag_unlink(struct mbuf *m, struct m_tag *t)
745 {
746 	SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
747 }
748 
749 /* These are for OpenBSD compatibility. */
750 #define	MTAG_ABI_COMPAT		0		/* compatibility ABI */
751 
752 static __inline struct m_tag *
753 m_tag_get(int type, int length, int wait)
754 {
755 	return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
756 }
757 
758 static __inline struct m_tag *
759 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
760 {
761 	return (SLIST_EMPTY(&m->m_pkthdr.tags) ?
762 	    NULL : m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
763 }
764 
765 #endif /* _KERNEL */
766 
767 #endif /* !_SYS_MBUF_H_ */
768