xref: /freebsd/sys/sys/mbuf.h (revision f0cfa1b168014f56c02b83e5f28412cc5f78d117)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1988, 1993
5  *	The Regents of the University of California.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  *	@(#)mbuf.h	8.5 (Berkeley) 2/19/95
33  * $FreeBSD$
34  */
35 
36 #ifndef _SYS_MBUF_H_
37 #define	_SYS_MBUF_H_
38 
39 /* XXX: These includes suck. Sorry! */
40 #include <sys/queue.h>
41 #ifdef _KERNEL
42 #include <sys/systm.h>
43 #include <vm/uma.h>
44 #ifdef WITNESS
45 #include <sys/lock.h>
46 #endif
47 #endif
48 
49 #ifdef _KERNEL
50 #include <sys/sdt.h>
51 
52 #define	MBUF_PROBE1(probe, arg0)					\
53 	SDT_PROBE1(sdt, , , probe, arg0)
54 #define	MBUF_PROBE2(probe, arg0, arg1)					\
55 	SDT_PROBE2(sdt, , , probe, arg0, arg1)
56 #define	MBUF_PROBE3(probe, arg0, arg1, arg2)				\
57 	SDT_PROBE3(sdt, , , probe, arg0, arg1, arg2)
58 #define	MBUF_PROBE4(probe, arg0, arg1, arg2, arg3)			\
59 	SDT_PROBE4(sdt, , , probe, arg0, arg1, arg2, arg3)
60 #define	MBUF_PROBE5(probe, arg0, arg1, arg2, arg3, arg4)		\
61 	SDT_PROBE5(sdt, , , probe, arg0, arg1, arg2, arg3, arg4)
62 
63 SDT_PROBE_DECLARE(sdt, , , m__init);
64 SDT_PROBE_DECLARE(sdt, , , m__gethdr);
65 SDT_PROBE_DECLARE(sdt, , , m__get);
66 SDT_PROBE_DECLARE(sdt, , , m__getcl);
67 SDT_PROBE_DECLARE(sdt, , , m__clget);
68 SDT_PROBE_DECLARE(sdt, , , m__cljget);
69 SDT_PROBE_DECLARE(sdt, , , m__cljset);
70 SDT_PROBE_DECLARE(sdt, , , m__free);
71 SDT_PROBE_DECLARE(sdt, , , m__freem);
72 
73 #endif /* _KERNEL */
74 
75 /*
76  * Mbufs are of a single size, MSIZE (sys/param.h), which includes overhead.
77  * An mbuf may add a single "mbuf cluster" of size MCLBYTES (also in
78  * sys/param.h), which has no additional overhead and is used instead of the
79  * internal data area; this is done when at least MINCLSIZE of data must be
80  * stored.  Additionally, it is possible to allocate a separate buffer
81  * externally and attach it to the mbuf in a way similar to that of mbuf
82  * clusters.
83  *
84  * NB: These calculation do not take actual compiler-induced alignment and
85  * padding inside the complete struct mbuf into account.  Appropriate
86  * attention is required when changing members of struct mbuf.
87  *
88  * MLEN is data length in a normal mbuf.
89  * MHLEN is data length in an mbuf with pktheader.
90  * MINCLSIZE is a smallest amount of data that should be put into cluster.
91  *
92  * Compile-time assertions in uipc_mbuf.c test these values to ensure that
93  * they are sensible.
94  */
95 struct mbuf;
96 #define	MHSIZE		offsetof(struct mbuf, m_dat)
97 #define	MPKTHSIZE	offsetof(struct mbuf, m_pktdat)
98 #define	MLEN		((int)(MSIZE - MHSIZE))
99 #define	MHLEN		((int)(MSIZE - MPKTHSIZE))
100 #define	MINCLSIZE	(MHLEN + 1)
101 
102 #ifdef _KERNEL
103 /*-
104  * Macro for type conversion: convert mbuf pointer to data pointer of correct
105  * type:
106  *
107  * mtod(m, t)	-- Convert mbuf pointer to data pointer of correct type.
108  * mtodo(m, o) -- Same as above but with offset 'o' into data.
109  */
110 #define	mtod(m, t)	((t)((m)->m_data))
111 #define	mtodo(m, o)	((void *)(((m)->m_data) + (o)))
112 
113 /*
114  * Argument structure passed to UMA routines during mbuf and packet
115  * allocations.
116  */
117 struct mb_args {
118 	int	flags;	/* Flags for mbuf being allocated */
119 	short	type;	/* Type of mbuf being allocated */
120 };
121 #endif /* _KERNEL */
122 
123 /*
124  * Packet tag structure (see below for details).
125  */
126 struct m_tag {
127 	SLIST_ENTRY(m_tag)	m_tag_link;	/* List of packet tags */
128 	u_int16_t		m_tag_id;	/* Tag ID */
129 	u_int16_t		m_tag_len;	/* Length of data */
130 	u_int32_t		m_tag_cookie;	/* ABI/Module ID */
131 	void			(*m_tag_free)(struct m_tag *);
132 };
133 
134 /*
135  * Static network interface owned tag.
136  * Allocated through ifp->if_snd_tag_alloc().
137  */
138 struct m_snd_tag {
139 	struct ifnet *ifp;		/* network interface tag belongs to */
140 };
141 
142 /*
143  * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
144  * Size ILP32: 48
145  *	 LP64: 56
146  * Compile-time assertions in uipc_mbuf.c test these values to ensure that
147  * they are correct.
148  */
149 struct pkthdr {
150 	union {
151 		struct m_snd_tag *snd_tag;	/* send tag, if any */
152 		struct ifnet	*rcvif;		/* rcv interface */
153 	};
154 	SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
155 	int32_t		 len;		/* total packet length */
156 
157 	/* Layer crossing persistent information. */
158 	uint32_t	 flowid;	/* packet's 4-tuple system */
159 	uint32_t	 csum_flags;	/* checksum and offload features */
160 	uint16_t	 fibnum;	/* this packet should use this fib */
161 	uint8_t		 cosqos;	/* class/quality of service */
162 	uint8_t		 rsstype;	/* hash type */
163 	union {
164 		uint64_t	rcv_tstmp;	/* timestamp in ns */
165 		struct {
166 			uint8_t		 l2hlen;	/* layer 2 hdr len */
167 			uint8_t		 l3hlen;	/* layer 3 hdr len */
168 			uint8_t		 l4hlen;	/* layer 4 hdr len */
169 			uint8_t		 l5hlen;	/* layer 5 hdr len */
170 			uint32_t	 spare;
171 		};
172 	};
173 	union {
174 		uint8_t  eight[8];
175 		uint16_t sixteen[4];
176 		uint32_t thirtytwo[2];
177 		uint64_t sixtyfour[1];
178 		uintptr_t unintptr[1];
179 		void	*ptr;
180 	} PH_per;
181 
182 	/* Layer specific non-persistent local storage for reassembly, etc. */
183 	union {
184 		uint8_t  eight[8];
185 		uint16_t sixteen[4];
186 		uint32_t thirtytwo[2];
187 		uint64_t sixtyfour[1];
188 		uintptr_t unintptr[1];
189 		void 	*ptr;
190 	} PH_loc;
191 };
192 #define	ether_vtag	PH_per.sixteen[0]
193 #define	PH_vt		PH_per
194 #define	vt_nrecs	sixteen[0]
195 #define	tso_segsz	PH_per.sixteen[1]
196 #define	lro_nsegs	tso_segsz
197 #define	csum_phsum	PH_per.sixteen[2]
198 #define	csum_data	PH_per.thirtytwo[1]
199 
200 /*
201  * Description of external storage mapped into mbuf; valid only if M_EXT is
202  * set.
203  * Size ILP32: 28
204  *	 LP64: 48
205  * Compile-time assertions in uipc_mbuf.c test these values to ensure that
206  * they are correct.
207  */
208 typedef	void m_ext_free_t(struct mbuf *);
209 struct m_ext {
210 	union {
211 		/*
212 		 * If EXT_FLAG_EMBREF is set, then we use refcount in the
213 		 * mbuf, the 'ext_count' member.  Otherwise, we have a
214 		 * shadow copy and we use pointer 'ext_cnt'.  The original
215 		 * mbuf is responsible to carry the pointer to free routine
216 		 * and its arguments.  They aren't copied into shadows in
217 		 * mb_dupcl() to avoid dereferencing next cachelines.
218 		 */
219 		volatile u_int	 ext_count;
220 		volatile u_int	*ext_cnt;
221 	};
222 	char		*ext_buf;	/* start of buffer */
223 	uint32_t	 ext_size;	/* size of buffer, for ext_free */
224 	uint32_t	 ext_type:8,	/* type of external storage */
225 			 ext_flags:24;	/* external storage mbuf flags */
226 	/*
227 	 * Fields below store the free context for the external storage.
228 	 * They are valid only in the refcount carrying mbuf, the one with
229 	 * EXT_FLAG_EMBREF flag, with exclusion for EXT_EXTREF type, where
230 	 * the free context is copied into all mbufs that use same external
231 	 * storage.
232 	 */
233 #define	m_ext_copylen	offsetof(struct m_ext, ext_free)
234 	m_ext_free_t	*ext_free;	/* free routine if not the usual */
235 	void		*ext_arg1;	/* optional argument pointer */
236 	void		*ext_arg2;	/* optional argument pointer */
237 };
238 
239 /*
240  * The core of the mbuf object along with some shortcut defines for practical
241  * purposes.
242  */
243 struct mbuf {
244 	/*
245 	 * Header present at the beginning of every mbuf.
246 	 * Size ILP32: 24
247 	 *      LP64: 32
248 	 * Compile-time assertions in uipc_mbuf.c test these values to ensure
249 	 * that they are correct.
250 	 */
251 	union {	/* next buffer in chain */
252 		struct mbuf		*m_next;
253 		SLIST_ENTRY(mbuf)	m_slist;
254 		STAILQ_ENTRY(mbuf)	m_stailq;
255 	};
256 	union {	/* next chain in queue/record */
257 		struct mbuf		*m_nextpkt;
258 		SLIST_ENTRY(mbuf)	m_slistpkt;
259 		STAILQ_ENTRY(mbuf)	m_stailqpkt;
260 	};
261 	caddr_t		 m_data;	/* location of data */
262 	int32_t		 m_len;		/* amount of data in this mbuf */
263 	uint32_t	 m_type:8,	/* type of data in this mbuf */
264 			 m_flags:24;	/* flags; see below */
265 #if !defined(__LP64__)
266 	uint32_t	 m_pad;		/* pad for 64bit alignment */
267 #endif
268 
269 	/*
270 	 * A set of optional headers (packet header, external storage header)
271 	 * and internal data storage.  Historically, these arrays were sized
272 	 * to MHLEN (space left after a packet header) and MLEN (space left
273 	 * after only a regular mbuf header); they are now variable size in
274 	 * order to support future work on variable-size mbufs.
275 	 */
276 	union {
277 		struct {
278 			struct pkthdr	m_pkthdr;	/* M_PKTHDR set */
279 			union {
280 				struct m_ext	m_ext;	/* M_EXT set */
281 				char		m_pktdat[0];
282 			};
283 		};
284 		char	m_dat[0];			/* !M_PKTHDR, !M_EXT */
285 	};
286 };
287 
288 /*
289  * mbuf flags of global significance and layer crossing.
290  * Those of only protocol/layer specific significance are to be mapped
291  * to M_PROTO[1-12] and cleared at layer handoff boundaries.
292  * NB: Limited to the lower 24 bits.
293  */
294 #define	M_EXT		0x00000001 /* has associated external storage */
295 #define	M_PKTHDR	0x00000002 /* start of record */
296 #define	M_EOR		0x00000004 /* end of record */
297 #define	M_RDONLY	0x00000008 /* associated data is marked read-only */
298 #define	M_BCAST		0x00000010 /* send/received as link-level broadcast */
299 #define	M_MCAST		0x00000020 /* send/received as link-level multicast */
300 #define	M_PROMISC	0x00000040 /* packet was not for us */
301 #define	M_VLANTAG	0x00000080 /* ether_vtag is valid */
302 #define	M_UNUSED_8	0x00000100 /* --available-- */
303 #define	M_NOFREE	0x00000200 /* do not free mbuf, embedded in cluster */
304 #define	M_TSTMP		0x00000400 /* rcv_tstmp field is valid */
305 #define	M_TSTMP_HPREC	0x00000800 /* rcv_tstmp is high-prec, typically
306 				      hw-stamped on port (useful for IEEE 1588
307 				      and 802.1AS) */
308 
309 #define	M_PROTO1	0x00001000 /* protocol-specific */
310 #define	M_PROTO2	0x00002000 /* protocol-specific */
311 #define	M_PROTO3	0x00004000 /* protocol-specific */
312 #define	M_PROTO4	0x00008000 /* protocol-specific */
313 #define	M_PROTO5	0x00010000 /* protocol-specific */
314 #define	M_PROTO6	0x00020000 /* protocol-specific */
315 #define	M_PROTO7	0x00040000 /* protocol-specific */
316 #define	M_PROTO8	0x00080000 /* protocol-specific */
317 #define	M_PROTO9	0x00100000 /* protocol-specific */
318 #define	M_PROTO10	0x00200000 /* protocol-specific */
319 #define	M_PROTO11	0x00400000 /* protocol-specific */
320 #define	M_PROTO12	0x00800000 /* protocol-specific */
321 
322 #define MB_DTOR_SKIP	0x1	/* don't pollute the cache by touching a freed mbuf */
323 
324 /*
325  * Flags to purge when crossing layers.
326  */
327 #define	M_PROTOFLAGS \
328     (M_PROTO1|M_PROTO2|M_PROTO3|M_PROTO4|M_PROTO5|M_PROTO6|M_PROTO7|M_PROTO8|\
329      M_PROTO9|M_PROTO10|M_PROTO11|M_PROTO12)
330 
331 /*
332  * Flags preserved when copying m_pkthdr.
333  */
334 #define M_COPYFLAGS \
335     (M_PKTHDR|M_EOR|M_RDONLY|M_BCAST|M_MCAST|M_PROMISC|M_VLANTAG|M_TSTMP| \
336      M_TSTMP_HPREC|M_PROTOFLAGS)
337 
338 /*
339  * Mbuf flag description for use with printf(9) %b identifier.
340  */
341 #define	M_FLAG_BITS \
342     "\20\1M_EXT\2M_PKTHDR\3M_EOR\4M_RDONLY\5M_BCAST\6M_MCAST" \
343     "\7M_PROMISC\10M_VLANTAG\13M_TSTMP\14M_TSTMP_HPREC"
344 #define	M_FLAG_PROTOBITS \
345     "\15M_PROTO1\16M_PROTO2\17M_PROTO3\20M_PROTO4\21M_PROTO5" \
346     "\22M_PROTO6\23M_PROTO7\24M_PROTO8\25M_PROTO9\26M_PROTO10" \
347     "\27M_PROTO11\30M_PROTO12"
348 #define	M_FLAG_PRINTF (M_FLAG_BITS M_FLAG_PROTOBITS)
349 
350 /*
351  * Network interface cards are able to hash protocol fields (such as IPv4
352  * addresses and TCP port numbers) classify packets into flows.  These flows
353  * can then be used to maintain ordering while delivering packets to the OS
354  * via parallel input queues, as well as to provide a stateless affinity
355  * model.  NIC drivers can pass up the hash via m->m_pkthdr.flowid, and set
356  * m_flag fields to indicate how the hash should be interpreted by the
357  * network stack.
358  *
359  * Most NICs support RSS, which provides ordering and explicit affinity, and
360  * use the hash m_flag bits to indicate what header fields were covered by
361  * the hash.  M_HASHTYPE_OPAQUE and M_HASHTYPE_OPAQUE_HASH can be set by non-
362  * RSS cards or configurations that provide an opaque flow identifier, allowing
363  * for ordering and distribution without explicit affinity.  Additionally,
364  * M_HASHTYPE_OPAQUE_HASH indicates that the flow identifier has hash
365  * properties.
366  *
367  * The meaning of the IPV6_EX suffix:
368  * "o  Home address from the home address option in the IPv6 destination
369  *     options header.  If the extension header is not present, use the Source
370  *     IPv6 Address.
371  *  o  IPv6 address that is contained in the Routing-Header-Type-2 from the
372  *     associated extension header.  If the extension header is not present,
373  *     use the Destination IPv6 Address."
374  * Quoted from:
375  * https://docs.microsoft.com/en-us/windows-hardware/drivers/network/rss-hashing-types#ndishashipv6ex
376  */
377 #define	M_HASHTYPE_HASHPROP		0x80	/* has hash properties */
378 #define	M_HASHTYPE_HASH(t)		(M_HASHTYPE_HASHPROP | (t))
379 /* Microsoft RSS standard hash types */
380 #define	M_HASHTYPE_NONE			0
381 #define	M_HASHTYPE_RSS_IPV4		M_HASHTYPE_HASH(1) /* IPv4 2-tuple */
382 #define	M_HASHTYPE_RSS_TCP_IPV4		M_HASHTYPE_HASH(2) /* TCPv4 4-tuple */
383 #define	M_HASHTYPE_RSS_IPV6		M_HASHTYPE_HASH(3) /* IPv6 2-tuple */
384 #define	M_HASHTYPE_RSS_TCP_IPV6		M_HASHTYPE_HASH(4) /* TCPv6 4-tuple */
385 #define	M_HASHTYPE_RSS_IPV6_EX		M_HASHTYPE_HASH(5) /* IPv6 2-tuple +
386 							    * ext hdrs */
387 #define	M_HASHTYPE_RSS_TCP_IPV6_EX	M_HASHTYPE_HASH(6) /* TCPv6 4-tuple +
388 							    * ext hdrs */
389 #define	M_HASHTYPE_RSS_UDP_IPV4		M_HASHTYPE_HASH(7) /* IPv4 UDP 4-tuple*/
390 #define	M_HASHTYPE_RSS_UDP_IPV6		M_HASHTYPE_HASH(9) /* IPv6 UDP 4-tuple*/
391 #define	M_HASHTYPE_RSS_UDP_IPV6_EX	M_HASHTYPE_HASH(10)/* IPv6 UDP 4-tuple +
392 							    * ext hdrs */
393 
394 #define	M_HASHTYPE_OPAQUE		63	/* ordering, not affinity */
395 #define	M_HASHTYPE_OPAQUE_HASH		M_HASHTYPE_HASH(M_HASHTYPE_OPAQUE)
396 						/* ordering+hash, not affinity*/
397 
398 #define	M_HASHTYPE_CLEAR(m)	((m)->m_pkthdr.rsstype = 0)
399 #define	M_HASHTYPE_GET(m)	((m)->m_pkthdr.rsstype)
400 #define	M_HASHTYPE_SET(m, v)	((m)->m_pkthdr.rsstype = (v))
401 #define	M_HASHTYPE_TEST(m, v)	(M_HASHTYPE_GET(m) == (v))
402 #define	M_HASHTYPE_ISHASH(m)	(M_HASHTYPE_GET(m) & M_HASHTYPE_HASHPROP)
403 
404 /*
405  * COS/QOS class and quality of service tags.
406  * It uses DSCP code points as base.
407  */
408 #define	QOS_DSCP_CS0		0x00
409 #define	QOS_DSCP_DEF		QOS_DSCP_CS0
410 #define	QOS_DSCP_CS1		0x20
411 #define	QOS_DSCP_AF11		0x28
412 #define	QOS_DSCP_AF12		0x30
413 #define	QOS_DSCP_AF13		0x38
414 #define	QOS_DSCP_CS2		0x40
415 #define	QOS_DSCP_AF21		0x48
416 #define	QOS_DSCP_AF22		0x50
417 #define	QOS_DSCP_AF23		0x58
418 #define	QOS_DSCP_CS3		0x60
419 #define	QOS_DSCP_AF31		0x68
420 #define	QOS_DSCP_AF32		0x70
421 #define	QOS_DSCP_AF33		0x78
422 #define	QOS_DSCP_CS4		0x80
423 #define	QOS_DSCP_AF41		0x88
424 #define	QOS_DSCP_AF42		0x90
425 #define	QOS_DSCP_AF43		0x98
426 #define	QOS_DSCP_CS5		0xa0
427 #define	QOS_DSCP_EF		0xb8
428 #define	QOS_DSCP_CS6		0xc0
429 #define	QOS_DSCP_CS7		0xe0
430 
431 /*
432  * External mbuf storage buffer types.
433  */
434 #define	EXT_CLUSTER	1	/* mbuf cluster */
435 #define	EXT_SFBUF	2	/* sendfile(2)'s sf_buf */
436 #define	EXT_JUMBOP	3	/* jumbo cluster page sized */
437 #define	EXT_JUMBO9	4	/* jumbo cluster 9216 bytes */
438 #define	EXT_JUMBO16	5	/* jumbo cluster 16184 bytes */
439 #define	EXT_PACKET	6	/* mbuf+cluster from packet zone */
440 #define	EXT_MBUF	7	/* external mbuf reference */
441 
442 #define	EXT_VENDOR1	224	/* for vendor-internal use */
443 #define	EXT_VENDOR2	225	/* for vendor-internal use */
444 #define	EXT_VENDOR3	226	/* for vendor-internal use */
445 #define	EXT_VENDOR4	227	/* for vendor-internal use */
446 
447 #define	EXT_EXP1	244	/* for experimental use */
448 #define	EXT_EXP2	245	/* for experimental use */
449 #define	EXT_EXP3	246	/* for experimental use */
450 #define	EXT_EXP4	247	/* for experimental use */
451 
452 #define	EXT_NET_DRV	252	/* custom ext_buf provided by net driver(s) */
453 #define	EXT_MOD_TYPE	253	/* custom module's ext_buf type */
454 #define	EXT_DISPOSABLE	254	/* can throw this buffer away w/page flipping */
455 #define	EXT_EXTREF	255	/* has externally maintained ext_cnt ptr */
456 
457 /*
458  * Flags for external mbuf buffer types.
459  * NB: limited to the lower 24 bits.
460  */
461 #define	EXT_FLAG_EMBREF		0x000001	/* embedded ext_count */
462 #define	EXT_FLAG_EXTREF		0x000002	/* external ext_cnt, notyet */
463 
464 #define	EXT_FLAG_NOFREE		0x000010	/* don't free mbuf to pool, notyet */
465 
466 #define	EXT_FLAG_VENDOR1	0x010000	/* These flags are vendor */
467 #define	EXT_FLAG_VENDOR2	0x020000	/* or submodule specific, */
468 #define	EXT_FLAG_VENDOR3	0x040000	/* not used by mbuf code. */
469 #define	EXT_FLAG_VENDOR4	0x080000	/* Set/read by submodule. */
470 
471 #define	EXT_FLAG_EXP1		0x100000	/* for experimental use */
472 #define	EXT_FLAG_EXP2		0x200000	/* for experimental use */
473 #define	EXT_FLAG_EXP3		0x400000	/* for experimental use */
474 #define	EXT_FLAG_EXP4		0x800000	/* for experimental use */
475 
476 /*
477  * EXT flag description for use with printf(9) %b identifier.
478  */
479 #define	EXT_FLAG_BITS \
480     "\20\1EXT_FLAG_EMBREF\2EXT_FLAG_EXTREF\5EXT_FLAG_NOFREE" \
481     "\21EXT_FLAG_VENDOR1\22EXT_FLAG_VENDOR2\23EXT_FLAG_VENDOR3" \
482     "\24EXT_FLAG_VENDOR4\25EXT_FLAG_EXP1\26EXT_FLAG_EXP2\27EXT_FLAG_EXP3" \
483     "\30EXT_FLAG_EXP4"
484 
485 /*
486  * Flags indicating checksum, segmentation and other offload work to be
487  * done, or already done, by hardware or lower layers.  It is split into
488  * separate inbound and outbound flags.
489  *
490  * Outbound flags that are set by upper protocol layers requesting lower
491  * layers, or ideally the hardware, to perform these offloading tasks.
492  * For outbound packets this field and its flags can be directly tested
493  * against ifnet if_hwassist.
494  */
495 #define	CSUM_IP			0x00000001	/* IP header checksum offload */
496 #define	CSUM_IP_UDP		0x00000002	/* UDP checksum offload */
497 #define	CSUM_IP_TCP		0x00000004	/* TCP checksum offload */
498 #define	CSUM_IP_SCTP		0x00000008	/* SCTP checksum offload */
499 #define	CSUM_IP_TSO		0x00000010	/* TCP segmentation offload */
500 #define	CSUM_IP_ISCSI		0x00000020	/* iSCSI checksum offload */
501 
502 #define	CSUM_IP6_UDP		0x00000200	/* UDP checksum offload */
503 #define	CSUM_IP6_TCP		0x00000400	/* TCP checksum offload */
504 #define	CSUM_IP6_SCTP		0x00000800	/* SCTP checksum offload */
505 #define	CSUM_IP6_TSO		0x00001000	/* TCP segmentation offload */
506 #define	CSUM_IP6_ISCSI		0x00002000	/* iSCSI checksum offload */
507 
508 /* Inbound checksum support where the checksum was verified by hardware. */
509 #define	CSUM_L3_CALC		0x01000000	/* calculated layer 3 csum */
510 #define	CSUM_L3_VALID		0x02000000	/* checksum is correct */
511 #define	CSUM_L4_CALC		0x04000000	/* calculated layer 4 csum */
512 #define	CSUM_L4_VALID		0x08000000	/* checksum is correct */
513 #define	CSUM_L5_CALC		0x10000000	/* calculated layer 5 csum */
514 #define	CSUM_L5_VALID		0x20000000	/* checksum is correct */
515 #define	CSUM_COALESCED		0x40000000	/* contains merged segments */
516 
517 /*
518  * CSUM flag description for use with printf(9) %b identifier.
519  */
520 #define	CSUM_BITS \
521     "\20\1CSUM_IP\2CSUM_IP_UDP\3CSUM_IP_TCP\4CSUM_IP_SCTP\5CSUM_IP_TSO" \
522     "\6CSUM_IP_ISCSI" \
523     "\12CSUM_IP6_UDP\13CSUM_IP6_TCP\14CSUM_IP6_SCTP\15CSUM_IP6_TSO" \
524     "\16CSUM_IP6_ISCSI" \
525     "\31CSUM_L3_CALC\32CSUM_L3_VALID\33CSUM_L4_CALC\34CSUM_L4_VALID" \
526     "\35CSUM_L5_CALC\36CSUM_L5_VALID\37CSUM_COALESCED"
527 
528 /* CSUM flags compatibility mappings. */
529 #define	CSUM_IP_CHECKED		CSUM_L3_CALC
530 #define	CSUM_IP_VALID		CSUM_L3_VALID
531 #define	CSUM_DATA_VALID		CSUM_L4_VALID
532 #define	CSUM_PSEUDO_HDR		CSUM_L4_CALC
533 #define	CSUM_SCTP_VALID		CSUM_L4_VALID
534 #define	CSUM_DELAY_DATA		(CSUM_TCP|CSUM_UDP)
535 #define	CSUM_DELAY_IP		CSUM_IP		/* Only v4, no v6 IP hdr csum */
536 #define	CSUM_DELAY_DATA_IPV6	(CSUM_TCP_IPV6|CSUM_UDP_IPV6)
537 #define	CSUM_DATA_VALID_IPV6	CSUM_DATA_VALID
538 #define	CSUM_TCP		CSUM_IP_TCP
539 #define	CSUM_UDP		CSUM_IP_UDP
540 #define	CSUM_SCTP		CSUM_IP_SCTP
541 #define	CSUM_TSO		(CSUM_IP_TSO|CSUM_IP6_TSO)
542 #define	CSUM_UDP_IPV6		CSUM_IP6_UDP
543 #define	CSUM_TCP_IPV6		CSUM_IP6_TCP
544 #define	CSUM_SCTP_IPV6		CSUM_IP6_SCTP
545 
546 /*
547  * mbuf types describing the content of the mbuf (including external storage).
548  */
549 #define	MT_NOTMBUF	0	/* USED INTERNALLY ONLY! Object is not mbuf */
550 #define	MT_DATA		1	/* dynamic (data) allocation */
551 #define	MT_HEADER	MT_DATA	/* packet header, use M_PKTHDR instead */
552 
553 #define	MT_VENDOR1	4	/* for vendor-internal use */
554 #define	MT_VENDOR2	5	/* for vendor-internal use */
555 #define	MT_VENDOR3	6	/* for vendor-internal use */
556 #define	MT_VENDOR4	7	/* for vendor-internal use */
557 
558 #define	MT_SONAME	8	/* socket name */
559 
560 #define	MT_EXP1		9	/* for experimental use */
561 #define	MT_EXP2		10	/* for experimental use */
562 #define	MT_EXP3		11	/* for experimental use */
563 #define	MT_EXP4		12	/* for experimental use */
564 
565 #define	MT_CONTROL	14	/* extra-data protocol message */
566 #define	MT_OOBDATA	15	/* expedited data  */
567 #define	MT_NTYPES	16	/* number of mbuf types for mbtypes[] */
568 
569 #define	MT_NOINIT	255	/* Not a type but a flag to allocate
570 				   a non-initialized mbuf */
571 
572 /*
573  * String names of mbuf-related UMA(9) and malloc(9) types.  Exposed to
574  * !_KERNEL so that monitoring tools can look up the zones with
575  * libmemstat(3).
576  */
577 #define	MBUF_MEM_NAME		"mbuf"
578 #define	MBUF_CLUSTER_MEM_NAME	"mbuf_cluster"
579 #define	MBUF_PACKET_MEM_NAME	"mbuf_packet"
580 #define	MBUF_JUMBOP_MEM_NAME	"mbuf_jumbo_page"
581 #define	MBUF_JUMBO9_MEM_NAME	"mbuf_jumbo_9k"
582 #define	MBUF_JUMBO16_MEM_NAME	"mbuf_jumbo_16k"
583 #define	MBUF_TAG_MEM_NAME	"mbuf_tag"
584 #define	MBUF_EXTREFCNT_MEM_NAME	"mbuf_ext_refcnt"
585 
586 #ifdef _KERNEL
587 
588 #ifdef WITNESS
589 #define	MBUF_CHECKSLEEP(how) do {					\
590 	if (how == M_WAITOK)						\
591 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,		\
592 		    "Sleeping in \"%s\"", __func__);			\
593 } while (0)
594 #else
595 #define	MBUF_CHECKSLEEP(how)
596 #endif
597 
598 /*
599  * Network buffer allocation API
600  *
601  * The rest of it is defined in kern/kern_mbuf.c
602  */
603 extern uma_zone_t	zone_mbuf;
604 extern uma_zone_t	zone_clust;
605 extern uma_zone_t	zone_pack;
606 extern uma_zone_t	zone_jumbop;
607 extern uma_zone_t	zone_jumbo9;
608 extern uma_zone_t	zone_jumbo16;
609 
610 void		 mb_dupcl(struct mbuf *, struct mbuf *);
611 void		 mb_free_ext(struct mbuf *);
612 void		 m_adj(struct mbuf *, int);
613 int		 m_apply(struct mbuf *, int, int,
614 		    int (*)(void *, void *, u_int), void *);
615 int		 m_append(struct mbuf *, int, c_caddr_t);
616 void		 m_cat(struct mbuf *, struct mbuf *);
617 void		 m_catpkt(struct mbuf *, struct mbuf *);
618 int		 m_clget(struct mbuf *m, int how);
619 void 		*m_cljget(struct mbuf *m, int how, int size);
620 struct mbuf	*m_collapse(struct mbuf *, int, int);
621 void		 m_copyback(struct mbuf *, int, int, c_caddr_t);
622 void		 m_copydata(const struct mbuf *, int, int, caddr_t);
623 struct mbuf	*m_copym(struct mbuf *, int, int, int);
624 struct mbuf	*m_copypacket(struct mbuf *, int);
625 void		 m_copy_pkthdr(struct mbuf *, struct mbuf *);
626 struct mbuf	*m_copyup(struct mbuf *, int, int);
627 struct mbuf	*m_defrag(struct mbuf *, int);
628 void		 m_demote_pkthdr(struct mbuf *);
629 void		 m_demote(struct mbuf *, int, int);
630 struct mbuf	*m_devget(char *, int, int, struct ifnet *,
631 		    void (*)(char *, caddr_t, u_int));
632 struct mbuf	*m_dup(const struct mbuf *, int);
633 int		 m_dup_pkthdr(struct mbuf *, const struct mbuf *, int);
634 void		 m_extadd(struct mbuf *, char *, u_int, m_ext_free_t,
635 		    void *, void *, int, int);
636 u_int		 m_fixhdr(struct mbuf *);
637 struct mbuf	*m_fragment(struct mbuf *, int, int);
638 void		 m_freem(struct mbuf *);
639 struct mbuf	*m_get2(int, int, short, int);
640 struct mbuf	*m_getjcl(int, short, int, int);
641 struct mbuf	*m_getm2(struct mbuf *, int, int, short, int);
642 struct mbuf	*m_getptr(struct mbuf *, int, int *);
643 u_int		 m_length(struct mbuf *, struct mbuf **);
644 int		 m_mbuftouio(struct uio *, const struct mbuf *, int);
645 void		 m_move_pkthdr(struct mbuf *, struct mbuf *);
646 int		 m_pkthdr_init(struct mbuf *, int);
647 struct mbuf	*m_prepend(struct mbuf *, int, int);
648 void		 m_print(const struct mbuf *, int);
649 struct mbuf	*m_pulldown(struct mbuf *, int, int, int *);
650 struct mbuf	*m_pullup(struct mbuf *, int);
651 int		 m_sanity(struct mbuf *, int);
652 struct mbuf	*m_split(struct mbuf *, int, int);
653 struct mbuf	*m_uiotombuf(struct uio *, int, int, int, int);
654 struct mbuf	*m_unshare(struct mbuf *, int);
655 
656 static __inline int
657 m_gettype(int size)
658 {
659 	int type;
660 
661 	switch (size) {
662 	case MSIZE:
663 		type = EXT_MBUF;
664 		break;
665 	case MCLBYTES:
666 		type = EXT_CLUSTER;
667 		break;
668 #if MJUMPAGESIZE != MCLBYTES
669 	case MJUMPAGESIZE:
670 		type = EXT_JUMBOP;
671 		break;
672 #endif
673 	case MJUM9BYTES:
674 		type = EXT_JUMBO9;
675 		break;
676 	case MJUM16BYTES:
677 		type = EXT_JUMBO16;
678 		break;
679 	default:
680 		panic("%s: invalid cluster size %d", __func__, size);
681 	}
682 
683 	return (type);
684 }
685 
686 /*
687  * Associated an external reference counted buffer with an mbuf.
688  */
689 static __inline void
690 m_extaddref(struct mbuf *m, char *buf, u_int size, u_int *ref_cnt,
691     m_ext_free_t freef, void *arg1, void *arg2)
692 {
693 
694 	KASSERT(ref_cnt != NULL, ("%s: ref_cnt not provided", __func__));
695 
696 	atomic_add_int(ref_cnt, 1);
697 	m->m_flags |= M_EXT;
698 	m->m_ext.ext_buf = buf;
699 	m->m_ext.ext_cnt = ref_cnt;
700 	m->m_data = m->m_ext.ext_buf;
701 	m->m_ext.ext_size = size;
702 	m->m_ext.ext_free = freef;
703 	m->m_ext.ext_arg1 = arg1;
704 	m->m_ext.ext_arg2 = arg2;
705 	m->m_ext.ext_type = EXT_EXTREF;
706 	m->m_ext.ext_flags = 0;
707 }
708 
709 static __inline uma_zone_t
710 m_getzone(int size)
711 {
712 	uma_zone_t zone;
713 
714 	switch (size) {
715 	case MCLBYTES:
716 		zone = zone_clust;
717 		break;
718 #if MJUMPAGESIZE != MCLBYTES
719 	case MJUMPAGESIZE:
720 		zone = zone_jumbop;
721 		break;
722 #endif
723 	case MJUM9BYTES:
724 		zone = zone_jumbo9;
725 		break;
726 	case MJUM16BYTES:
727 		zone = zone_jumbo16;
728 		break;
729 	default:
730 		panic("%s: invalid cluster size %d", __func__, size);
731 	}
732 
733 	return (zone);
734 }
735 
736 /*
737  * Initialize an mbuf with linear storage.
738  *
739  * Inline because the consumer text overhead will be roughly the same to
740  * initialize or call a function with this many parameters and M_PKTHDR
741  * should go away with constant propagation for !MGETHDR.
742  */
743 static __inline int
744 m_init(struct mbuf *m, int how, short type, int flags)
745 {
746 	int error;
747 
748 	m->m_next = NULL;
749 	m->m_nextpkt = NULL;
750 	m->m_data = m->m_dat;
751 	m->m_len = 0;
752 	m->m_flags = flags;
753 	m->m_type = type;
754 	if (flags & M_PKTHDR)
755 		error = m_pkthdr_init(m, how);
756 	else
757 		error = 0;
758 
759 	MBUF_PROBE5(m__init, m, how, type, flags, error);
760 	return (error);
761 }
762 
763 static __inline struct mbuf *
764 m_get(int how, short type)
765 {
766 	struct mbuf *m;
767 	struct mb_args args;
768 
769 	args.flags = 0;
770 	args.type = type;
771 	m = uma_zalloc_arg(zone_mbuf, &args, how);
772 	MBUF_PROBE3(m__get, how, type, m);
773 	return (m);
774 }
775 
776 static __inline struct mbuf *
777 m_gethdr(int how, short type)
778 {
779 	struct mbuf *m;
780 	struct mb_args args;
781 
782 	args.flags = M_PKTHDR;
783 	args.type = type;
784 	m = uma_zalloc_arg(zone_mbuf, &args, how);
785 	MBUF_PROBE3(m__gethdr, how, type, m);
786 	return (m);
787 }
788 
789 static __inline struct mbuf *
790 m_getcl(int how, short type, int flags)
791 {
792 	struct mbuf *m;
793 	struct mb_args args;
794 
795 	args.flags = flags;
796 	args.type = type;
797 	m = uma_zalloc_arg(zone_pack, &args, how);
798 	MBUF_PROBE4(m__getcl, how, type, flags, m);
799 	return (m);
800 }
801 
802 /*
803  * XXX: m_cljset() is a dangerous API.  One must attach only a new,
804  * unreferenced cluster to an mbuf(9).  It is not possible to assert
805  * that, so care can be taken only by users of the API.
806  */
807 static __inline void
808 m_cljset(struct mbuf *m, void *cl, int type)
809 {
810 	int size;
811 
812 	switch (type) {
813 	case EXT_CLUSTER:
814 		size = MCLBYTES;
815 		break;
816 #if MJUMPAGESIZE != MCLBYTES
817 	case EXT_JUMBOP:
818 		size = MJUMPAGESIZE;
819 		break;
820 #endif
821 	case EXT_JUMBO9:
822 		size = MJUM9BYTES;
823 		break;
824 	case EXT_JUMBO16:
825 		size = MJUM16BYTES;
826 		break;
827 	default:
828 		panic("%s: unknown cluster type %d", __func__, type);
829 		break;
830 	}
831 
832 	m->m_data = m->m_ext.ext_buf = cl;
833 	m->m_ext.ext_free = m->m_ext.ext_arg1 = m->m_ext.ext_arg2 = NULL;
834 	m->m_ext.ext_size = size;
835 	m->m_ext.ext_type = type;
836 	m->m_ext.ext_flags = EXT_FLAG_EMBREF;
837 	m->m_ext.ext_count = 1;
838 	m->m_flags |= M_EXT;
839 	MBUF_PROBE3(m__cljset, m, cl, type);
840 }
841 
842 static __inline void
843 m_chtype(struct mbuf *m, short new_type)
844 {
845 
846 	m->m_type = new_type;
847 }
848 
849 static __inline void
850 m_clrprotoflags(struct mbuf *m)
851 {
852 
853 	while (m) {
854 		m->m_flags &= ~M_PROTOFLAGS;
855 		m = m->m_next;
856 	}
857 }
858 
859 static __inline struct mbuf *
860 m_last(struct mbuf *m)
861 {
862 
863 	while (m->m_next)
864 		m = m->m_next;
865 	return (m);
866 }
867 
868 static inline u_int
869 m_extrefcnt(struct mbuf *m)
870 {
871 
872 	KASSERT(m->m_flags & M_EXT, ("%s: M_EXT missing", __func__));
873 
874 	return ((m->m_ext.ext_flags & EXT_FLAG_EMBREF) ? m->m_ext.ext_count :
875 	    *m->m_ext.ext_cnt);
876 }
877 
878 /*
879  * mbuf, cluster, and external object allocation macros (for compatibility
880  * purposes).
881  */
882 #define	M_MOVE_PKTHDR(to, from)	m_move_pkthdr((to), (from))
883 #define	MGET(m, how, type)	((m) = m_get((how), (type)))
884 #define	MGETHDR(m, how, type)	((m) = m_gethdr((how), (type)))
885 #define	MCLGET(m, how)		m_clget((m), (how))
886 #define	MEXTADD(m, buf, size, free, arg1, arg2, flags, type)		\
887     m_extadd((m), (char *)(buf), (size), (free), (arg1), (arg2),	\
888     (flags), (type))
889 #define	m_getm(m, len, how, type)					\
890     m_getm2((m), (len), (how), (type), M_PKTHDR)
891 
892 /*
893  * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can
894  * be both the local data payload, or an external buffer area, depending on
895  * whether M_EXT is set).
896  */
897 #define	M_WRITABLE(m)	(!((m)->m_flags & M_RDONLY) &&			\
898 			 (!(((m)->m_flags & M_EXT)) ||			\
899 			 (m_extrefcnt(m) == 1)))
900 
901 /* Check if the supplied mbuf has a packet header, or else panic. */
902 #define	M_ASSERTPKTHDR(m)						\
903 	KASSERT((m) != NULL && (m)->m_flags & M_PKTHDR,			\
904 	    ("%s: no mbuf packet header!", __func__))
905 
906 /*
907  * Ensure that the supplied mbuf is a valid, non-free mbuf.
908  *
909  * XXX: Broken at the moment.  Need some UMA magic to make it work again.
910  */
911 #define	M_ASSERTVALID(m)						\
912 	KASSERT((((struct mbuf *)m)->m_flags & 0) == 0,			\
913 	    ("%s: attempted use of a free mbuf!", __func__))
914 
915 /*
916  * Return the address of the start of the buffer associated with an mbuf,
917  * handling external storage, packet-header mbufs, and regular data mbufs.
918  */
919 #define	M_START(m)							\
920 	(((m)->m_flags & M_EXT) ? (m)->m_ext.ext_buf :			\
921 	 ((m)->m_flags & M_PKTHDR) ? &(m)->m_pktdat[0] :		\
922 	 &(m)->m_dat[0])
923 
924 /*
925  * Return the size of the buffer associated with an mbuf, handling external
926  * storage, packet-header mbufs, and regular data mbufs.
927  */
928 #define	M_SIZE(m)							\
929 	(((m)->m_flags & M_EXT) ? (m)->m_ext.ext_size :			\
930 	 ((m)->m_flags & M_PKTHDR) ? MHLEN :				\
931 	 MLEN)
932 
933 /*
934  * Set the m_data pointer of a newly allocated mbuf to place an object of the
935  * specified size at the end of the mbuf, longword aligned.
936  *
937  * NB: Historically, we had M_ALIGN(), MH_ALIGN(), and MEXT_ALIGN() as
938  * separate macros, each asserting that it was called at the proper moment.
939  * This required callers to themselves test the storage type and call the
940  * right one.  Rather than require callers to be aware of those layout
941  * decisions, we centralize here.
942  */
943 static __inline void
944 m_align(struct mbuf *m, int len)
945 {
946 #ifdef INVARIANTS
947 	const char *msg = "%s: not a virgin mbuf";
948 #endif
949 	int adjust;
950 
951 	KASSERT(m->m_data == M_START(m), (msg, __func__));
952 
953 	adjust = M_SIZE(m) - len;
954 	m->m_data += adjust &~ (sizeof(long)-1);
955 }
956 
957 #define	M_ALIGN(m, len)		m_align(m, len)
958 #define	MH_ALIGN(m, len)	m_align(m, len)
959 #define	MEXT_ALIGN(m, len)	m_align(m, len)
960 
961 /*
962  * Compute the amount of space available before the current start of data in
963  * an mbuf.
964  *
965  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
966  * of checking writability of the mbuf data area rests solely with the caller.
967  *
968  * NB: In previous versions, M_LEADINGSPACE() would only check M_WRITABLE()
969  * for mbufs with external storage.  We now allow mbuf-embedded data to be
970  * read-only as well.
971  */
972 #define	M_LEADINGSPACE(m)						\
973 	(M_WRITABLE(m) ? ((m)->m_data - M_START(m)) : 0)
974 
975 /*
976  * Compute the amount of space available after the end of data in an mbuf.
977  *
978  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
979  * of checking writability of the mbuf data area rests solely with the caller.
980  *
981  * NB: In previous versions, M_TRAILINGSPACE() would only check M_WRITABLE()
982  * for mbufs with external storage.  We now allow mbuf-embedded data to be
983  * read-only as well.
984  */
985 #define	M_TRAILINGSPACE(m)						\
986 	(M_WRITABLE(m) ?						\
987 	    ((M_START(m) + M_SIZE(m)) - ((m)->m_data + (m)->m_len)) : 0)
988 
989 /*
990  * Arrange to prepend space of size plen to mbuf m.  If a new mbuf must be
991  * allocated, how specifies whether to wait.  If the allocation fails, the
992  * original mbuf chain is freed and m is set to NULL.
993  */
994 #define	M_PREPEND(m, plen, how) do {					\
995 	struct mbuf **_mmp = &(m);					\
996 	struct mbuf *_mm = *_mmp;					\
997 	int _mplen = (plen);						\
998 	int __mhow = (how);						\
999 									\
1000 	MBUF_CHECKSLEEP(how);						\
1001 	if (M_LEADINGSPACE(_mm) >= _mplen) {				\
1002 		_mm->m_data -= _mplen;					\
1003 		_mm->m_len += _mplen;					\
1004 	} else								\
1005 		_mm = m_prepend(_mm, _mplen, __mhow);			\
1006 	if (_mm != NULL && _mm->m_flags & M_PKTHDR)			\
1007 		_mm->m_pkthdr.len += _mplen;				\
1008 	*_mmp = _mm;							\
1009 } while (0)
1010 
1011 /*
1012  * Change mbuf to new type.  This is a relatively expensive operation and
1013  * should be avoided.
1014  */
1015 #define	MCHTYPE(m, t)	m_chtype((m), (t))
1016 
1017 /* Length to m_copy to copy all. */
1018 #define	M_COPYALL	1000000000
1019 
1020 extern int		max_datalen;	/* MHLEN - max_hdr */
1021 extern int		max_hdr;	/* Largest link + protocol header */
1022 extern int		max_linkhdr;	/* Largest link-level header */
1023 extern int		max_protohdr;	/* Largest protocol header */
1024 extern int		nmbclusters;	/* Maximum number of clusters */
1025 
1026 /*-
1027  * Network packets may have annotations attached by affixing a list of
1028  * "packet tags" to the pkthdr structure.  Packet tags are dynamically
1029  * allocated semi-opaque data structures that have a fixed header
1030  * (struct m_tag) that specifies the size of the memory block and a
1031  * <cookie,type> pair that identifies it.  The cookie is a 32-bit unique
1032  * unsigned value used to identify a module or ABI.  By convention this value
1033  * is chosen as the date+time that the module is created, expressed as the
1034  * number of seconds since the epoch (e.g., using date -u +'%s').  The type
1035  * value is an ABI/module-specific value that identifies a particular
1036  * annotation and is private to the module.  For compatibility with systems
1037  * like OpenBSD that define packet tags w/o an ABI/module cookie, the value
1038  * PACKET_ABI_COMPAT is used to implement m_tag_get and m_tag_find
1039  * compatibility shim functions and several tag types are defined below.
1040  * Users that do not require compatibility should use a private cookie value
1041  * so that packet tag-related definitions can be maintained privately.
1042  *
1043  * Note that the packet tag returned by m_tag_alloc has the default memory
1044  * alignment implemented by malloc.  To reference private data one can use a
1045  * construct like:
1046  *
1047  *	struct m_tag *mtag = m_tag_alloc(...);
1048  *	struct foo *p = (struct foo *)(mtag+1);
1049  *
1050  * if the alignment of struct m_tag is sufficient for referencing members of
1051  * struct foo.  Otherwise it is necessary to embed struct m_tag within the
1052  * private data structure to insure proper alignment; e.g.,
1053  *
1054  *	struct foo {
1055  *		struct m_tag	tag;
1056  *		...
1057  *	};
1058  *	struct foo *p = (struct foo *) m_tag_alloc(...);
1059  *	struct m_tag *mtag = &p->tag;
1060  */
1061 
1062 /*
1063  * Persistent tags stay with an mbuf until the mbuf is reclaimed.  Otherwise
1064  * tags are expected to ``vanish'' when they pass through a network
1065  * interface.  For most interfaces this happens normally as the tags are
1066  * reclaimed when the mbuf is free'd.  However in some special cases
1067  * reclaiming must be done manually.  An example is packets that pass through
1068  * the loopback interface.  Also, one must be careful to do this when
1069  * ``turning around'' packets (e.g., icmp_reflect).
1070  *
1071  * To mark a tag persistent bit-or this flag in when defining the tag id.
1072  * The tag will then be treated as described above.
1073  */
1074 #define	MTAG_PERSISTENT				0x800
1075 
1076 #define	PACKET_TAG_NONE				0  /* Nadda */
1077 
1078 /* Packet tags for use with PACKET_ABI_COMPAT. */
1079 #define	PACKET_TAG_IPSEC_IN_DONE		1  /* IPsec applied, in */
1080 #define	PACKET_TAG_IPSEC_OUT_DONE		2  /* IPsec applied, out */
1081 #define	PACKET_TAG_IPSEC_IN_CRYPTO_DONE		3  /* NIC IPsec crypto done */
1082 #define	PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED	4  /* NIC IPsec crypto req'ed */
1083 #define	PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO	5  /* NIC notifies IPsec */
1084 #define	PACKET_TAG_IPSEC_PENDING_TDB		6  /* Reminder to do IPsec */
1085 #define	PACKET_TAG_BRIDGE			7  /* Bridge processing done */
1086 #define	PACKET_TAG_GIF				8  /* GIF processing done */
1087 #define	PACKET_TAG_GRE				9  /* GRE processing done */
1088 #define	PACKET_TAG_IN_PACKET_CHECKSUM		10 /* NIC checksumming done */
1089 #define	PACKET_TAG_ENCAP			11 /* Encap.  processing */
1090 #define	PACKET_TAG_IPSEC_SOCKET			12 /* IPSEC socket ref */
1091 #define	PACKET_TAG_IPSEC_HISTORY		13 /* IPSEC history */
1092 #define	PACKET_TAG_IPV6_INPUT			14 /* IPV6 input processing */
1093 #define	PACKET_TAG_DUMMYNET			15 /* dummynet info */
1094 #define	PACKET_TAG_DIVERT			17 /* divert info */
1095 #define	PACKET_TAG_IPFORWARD			18 /* ipforward info */
1096 #define	PACKET_TAG_MACLABEL	(19 | MTAG_PERSISTENT) /* MAC label */
1097 #define	PACKET_TAG_PF		(21 | MTAG_PERSISTENT) /* PF/ALTQ information */
1098 #define	PACKET_TAG_RTSOCKFAM			25 /* rtsock sa family */
1099 #define	PACKET_TAG_IPOPTIONS			27 /* Saved IP options */
1100 #define	PACKET_TAG_CARP				28 /* CARP info */
1101 #define	PACKET_TAG_IPSEC_NAT_T_PORTS		29 /* two uint16_t */
1102 #define	PACKET_TAG_ND_OUTGOING			30 /* ND outgoing */
1103 
1104 /* Specific cookies and tags. */
1105 
1106 /* Packet tag routines. */
1107 struct m_tag	*m_tag_alloc(u_int32_t, int, int, int);
1108 void		 m_tag_delete(struct mbuf *, struct m_tag *);
1109 void		 m_tag_delete_chain(struct mbuf *, struct m_tag *);
1110 void		 m_tag_free_default(struct m_tag *);
1111 struct m_tag	*m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
1112 struct m_tag	*m_tag_copy(struct m_tag *, int);
1113 int		 m_tag_copy_chain(struct mbuf *, const struct mbuf *, int);
1114 void		 m_tag_delete_nonpersistent(struct mbuf *);
1115 
1116 /*
1117  * Initialize the list of tags associated with an mbuf.
1118  */
1119 static __inline void
1120 m_tag_init(struct mbuf *m)
1121 {
1122 
1123 	SLIST_INIT(&m->m_pkthdr.tags);
1124 }
1125 
1126 /*
1127  * Set up the contents of a tag.  Note that this does not fill in the free
1128  * method; the caller is expected to do that.
1129  *
1130  * XXX probably should be called m_tag_init, but that was already taken.
1131  */
1132 static __inline void
1133 m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
1134 {
1135 
1136 	t->m_tag_id = type;
1137 	t->m_tag_len = len;
1138 	t->m_tag_cookie = cookie;
1139 }
1140 
1141 /*
1142  * Reclaim resources associated with a tag.
1143  */
1144 static __inline void
1145 m_tag_free(struct m_tag *t)
1146 {
1147 
1148 	(*t->m_tag_free)(t);
1149 }
1150 
1151 /*
1152  * Return the first tag associated with an mbuf.
1153  */
1154 static __inline struct m_tag *
1155 m_tag_first(struct mbuf *m)
1156 {
1157 
1158 	return (SLIST_FIRST(&m->m_pkthdr.tags));
1159 }
1160 
1161 /*
1162  * Return the next tag in the list of tags associated with an mbuf.
1163  */
1164 static __inline struct m_tag *
1165 m_tag_next(struct mbuf *m __unused, struct m_tag *t)
1166 {
1167 
1168 	return (SLIST_NEXT(t, m_tag_link));
1169 }
1170 
1171 /*
1172  * Prepend a tag to the list of tags associated with an mbuf.
1173  */
1174 static __inline void
1175 m_tag_prepend(struct mbuf *m, struct m_tag *t)
1176 {
1177 
1178 	SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
1179 }
1180 
1181 /*
1182  * Unlink a tag from the list of tags associated with an mbuf.
1183  */
1184 static __inline void
1185 m_tag_unlink(struct mbuf *m, struct m_tag *t)
1186 {
1187 
1188 	SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
1189 }
1190 
1191 /* These are for OpenBSD compatibility. */
1192 #define	MTAG_ABI_COMPAT		0		/* compatibility ABI */
1193 
1194 static __inline struct m_tag *
1195 m_tag_get(int type, int length, int wait)
1196 {
1197 	return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
1198 }
1199 
1200 static __inline struct m_tag *
1201 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
1202 {
1203 	return (SLIST_EMPTY(&m->m_pkthdr.tags) ? (struct m_tag *)NULL :
1204 	    m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
1205 }
1206 
1207 static __inline struct mbuf *
1208 m_free(struct mbuf *m)
1209 {
1210 	struct mbuf *n = m->m_next;
1211 
1212 	MBUF_PROBE1(m__free, m);
1213 	if ((m->m_flags & (M_PKTHDR|M_NOFREE)) == (M_PKTHDR|M_NOFREE))
1214 		m_tag_delete_chain(m, NULL);
1215 	if (m->m_flags & M_EXT)
1216 		mb_free_ext(m);
1217 	else if ((m->m_flags & M_NOFREE) == 0)
1218 		uma_zfree(zone_mbuf, m);
1219 	return (n);
1220 }
1221 
1222 static __inline int
1223 rt_m_getfib(struct mbuf *m)
1224 {
1225 	KASSERT(m->m_flags & M_PKTHDR , ("Attempt to get FIB from non header mbuf."));
1226 	return (m->m_pkthdr.fibnum);
1227 }
1228 
1229 #define M_GETFIB(_m)   rt_m_getfib(_m)
1230 
1231 #define M_SETFIB(_m, _fib) do {						\
1232         KASSERT((_m)->m_flags & M_PKTHDR, ("Attempt to set FIB on non header mbuf."));	\
1233 	((_m)->m_pkthdr.fibnum) = (_fib);				\
1234 } while (0)
1235 
1236 /* flags passed as first argument for "m_ether_tcpip_hash()" */
1237 #define	MBUF_HASHFLAG_L2	(1 << 2)
1238 #define	MBUF_HASHFLAG_L3	(1 << 3)
1239 #define	MBUF_HASHFLAG_L4	(1 << 4)
1240 
1241 /* mbuf hashing helper routines */
1242 uint32_t	m_ether_tcpip_hash_init(void);
1243 uint32_t	m_ether_tcpip_hash(const uint32_t, const struct mbuf *, const uint32_t);
1244 
1245 #ifdef MBUF_PROFILING
1246  void m_profile(struct mbuf *m);
1247  #define M_PROFILE(m) m_profile(m)
1248 #else
1249  #define M_PROFILE(m)
1250 #endif
1251 
1252 struct mbufq {
1253 	STAILQ_HEAD(, mbuf)	mq_head;
1254 	int			mq_len;
1255 	int			mq_maxlen;
1256 };
1257 
1258 static inline void
1259 mbufq_init(struct mbufq *mq, int maxlen)
1260 {
1261 
1262 	STAILQ_INIT(&mq->mq_head);
1263 	mq->mq_maxlen = maxlen;
1264 	mq->mq_len = 0;
1265 }
1266 
1267 static inline struct mbuf *
1268 mbufq_flush(struct mbufq *mq)
1269 {
1270 	struct mbuf *m;
1271 
1272 	m = STAILQ_FIRST(&mq->mq_head);
1273 	STAILQ_INIT(&mq->mq_head);
1274 	mq->mq_len = 0;
1275 	return (m);
1276 }
1277 
1278 static inline void
1279 mbufq_drain(struct mbufq *mq)
1280 {
1281 	struct mbuf *m, *n;
1282 
1283 	n = mbufq_flush(mq);
1284 	while ((m = n) != NULL) {
1285 		n = STAILQ_NEXT(m, m_stailqpkt);
1286 		m_freem(m);
1287 	}
1288 }
1289 
1290 static inline struct mbuf *
1291 mbufq_first(const struct mbufq *mq)
1292 {
1293 
1294 	return (STAILQ_FIRST(&mq->mq_head));
1295 }
1296 
1297 static inline struct mbuf *
1298 mbufq_last(const struct mbufq *mq)
1299 {
1300 
1301 	return (STAILQ_LAST(&mq->mq_head, mbuf, m_stailqpkt));
1302 }
1303 
1304 static inline int
1305 mbufq_full(const struct mbufq *mq)
1306 {
1307 
1308 	return (mq->mq_len >= mq->mq_maxlen);
1309 }
1310 
1311 static inline int
1312 mbufq_len(const struct mbufq *mq)
1313 {
1314 
1315 	return (mq->mq_len);
1316 }
1317 
1318 static inline int
1319 mbufq_enqueue(struct mbufq *mq, struct mbuf *m)
1320 {
1321 
1322 	if (mbufq_full(mq))
1323 		return (ENOBUFS);
1324 	STAILQ_INSERT_TAIL(&mq->mq_head, m, m_stailqpkt);
1325 	mq->mq_len++;
1326 	return (0);
1327 }
1328 
1329 static inline struct mbuf *
1330 mbufq_dequeue(struct mbufq *mq)
1331 {
1332 	struct mbuf *m;
1333 
1334 	m = STAILQ_FIRST(&mq->mq_head);
1335 	if (m) {
1336 		STAILQ_REMOVE_HEAD(&mq->mq_head, m_stailqpkt);
1337 		m->m_nextpkt = NULL;
1338 		mq->mq_len--;
1339 	}
1340 	return (m);
1341 }
1342 
1343 static inline void
1344 mbufq_prepend(struct mbufq *mq, struct mbuf *m)
1345 {
1346 
1347 	STAILQ_INSERT_HEAD(&mq->mq_head, m, m_stailqpkt);
1348 	mq->mq_len++;
1349 }
1350 
1351 /*
1352  * Note: this doesn't enforce the maximum list size for dst.
1353  */
1354 static inline void
1355 mbufq_concat(struct mbufq *mq_dst, struct mbufq *mq_src)
1356 {
1357 
1358 	mq_dst->mq_len += mq_src->mq_len;
1359 	STAILQ_CONCAT(&mq_dst->mq_head, &mq_src->mq_head);
1360 	mq_src->mq_len = 0;
1361 }
1362 
1363 #ifdef _SYS_TIMESPEC_H_
1364 static inline void
1365 mbuf_tstmp2timespec(struct mbuf *m, struct timespec *ts)
1366 {
1367 
1368 	KASSERT((m->m_flags & M_PKTHDR) != 0, ("mbuf %p no M_PKTHDR", m));
1369 	KASSERT((m->m_flags & M_TSTMP) != 0, ("mbuf %p no M_TSTMP", m));
1370 	ts->tv_sec = m->m_pkthdr.rcv_tstmp / 1000000000;
1371 	ts->tv_nsec = m->m_pkthdr.rcv_tstmp % 1000000000;
1372 }
1373 #endif
1374 
1375 #endif /* _KERNEL */
1376 #endif /* !_SYS_MBUF_H_ */
1377