kernel - Fix excessive mbuf use in nfs_realign()
[dragonfly.git] / sys / sys / mbuf.h
CommitLineData
984263bc 1/*
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2 * Copyright (c) 2004 The DragonFly Project. All rights reserved.
3 *
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4 * Copyright (c) 1982, 1986, 1988, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * @(#)mbuf.h 8.5 (Berkeley) 2/19/95
36 * $FreeBSD: src/sys/sys/mbuf.h,v 1.44.2.17 2003/04/15 06:15:02 silby Exp $
cf12ba3c 37 * $DragonFly: src/sys/sys/mbuf.h,v 1.54 2008/10/19 08:39:55 sephe Exp $
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38 */
39
40#ifndef _SYS_MBUF_H_
41#define _SYS_MBUF_H_
42
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43#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
44
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45#ifndef _SYS_TYPES_H_
46#include <sys/types.h>
47#endif
48#ifndef _SYS_PARAM_H_
49#include <sys/param.h>
50#endif
51#ifndef _SYS_QUEUE_H_
984263bc 52#include <sys/queue.h>
1bd40720 53#endif
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54#ifndef _NET_NETISR_H_
55#include <net/netisr.h>
56#endif
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57
58/*
59 * Mbufs are of a single size, MSIZE (machine/param.h), which
60 * includes overhead. An mbuf may add a single "mbuf cluster" of size
61 * MCLBYTES (also in machine/param.h), which has no additional overhead
62 * and is used instead of the internal data area; this is done when
63 * at least MINCLSIZE of data must be stored.
64 */
65#define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */
66#define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */
67#define MINCLSIZE (MHLEN + 1) /* smallest amount to put in cluster */
68#define M_MAXCOMPRESS (MHLEN / 2) /* max amount to copy for compression */
69
70/*
71 * Macros for type conversion:
72 * mtod(m, t) -- Convert mbuf pointer to data pointer of correct type.
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73 * mtocl(x) - convert pointer within cluster to cluster index #
74 * cltom(x) - convert cluster # to ptr to beginning of cluster
75 */
76#define mtod(m, t) ((t)((m)->m_data))
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77
78/*
79 * Header present at the beginning of every mbuf.
80 */
81struct m_hdr {
82 struct mbuf *mh_next; /* next buffer in chain */
83 struct mbuf *mh_nextpkt; /* next chain in queue/record */
84 caddr_t mh_data; /* location of data */
85 int mh_len; /* amount of data in this mbuf */
1514ff2e 86 int mh_flags; /* flags; see below */
984263bc 87 short mh_type; /* type of data in this mbuf */
1514ff2e 88 short mh_pad; /* padding */
6aad077d 89 struct netmsg_packet mh_netmsg; /* hardware->proto stack msg */
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90};
91
92/*
93 * Packet tag structure (see below for details).
94 */
95struct m_tag {
96 SLIST_ENTRY(m_tag) m_tag_link; /* List of packet tags */
97 u_int16_t m_tag_id; /* Tag ID */
98 u_int16_t m_tag_len; /* Length of data */
99 u_int32_t m_tag_cookie; /* ABI/Module ID */
100};
101
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102SLIST_HEAD(packet_tags, m_tag);
103
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104/*
105 * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
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106 *
107 * Be careful: The fields have been carefully ordered to avoid hidden padding.
108 * Keep this in mind, when adding or removing fields!
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109 */
110struct pkthdr {
111 struct ifnet *rcvif; /* rcv interface */
112 int len; /* total packet length */
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113 struct packet_tags tags; /* list of packet tags */
114
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115 /* variables for ip and tcp reassembly */
116 void *header; /* pointer to packet header */
46ca7d86 117
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118 /* variables for hardware checksum */
119 int csum_flags; /* flags regarding checksum */
120 int csum_data; /* data field used by csum routines */
46ca7d86 121
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122 /* firewall flags */
123 uint32_t fw_flags; /* flags for PF */
124
02742ec6 125 /* variables for PF processing */
70224baa 126 uint16_t unused01; /* was PF tag id */
46ca7d86 127 uint8_t pf_routed; /* PF routing counter */
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128
129 /* variables for ALTQ processing */
130 uint8_t ecn_af; /* address family for ECN */
131 uint32_t altq_qid; /* queue id */
5950bf01 132 uint32_t altq_state_hash; /* identifies 'connections' */
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133
134 uint16_t ether_vlantag; /* ethernet 802.1p+q vlan tag */
6afb09f8 135 uint16_t hash; /* packet hash */
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136
137 uint16_t wlan_seqno; /* IEEE 802.11 seq no. */
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138};
139
140/*
141 * Description of external storage mapped into mbuf; valid only if M_EXT is set.
142 */
143struct m_ext {
144 caddr_t ext_buf; /* start of buffer */
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145 void (*ext_free)(void *);
146 u_int ext_size; /* size of buffer, for ext_free */
147 void (*ext_ref)(void *);
7eccf245 148 void *ext_arg;
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149};
150
151/*
152 * The core of the mbuf object along with some shortcut defines for
153 * practical purposes.
154 */
155struct mbuf {
156 struct m_hdr m_hdr;
157 union {
158 struct {
159 struct pkthdr MH_pkthdr; /* M_PKTHDR set */
160 union {
161 struct m_ext MH_ext; /* M_EXT set */
162 char MH_databuf[MHLEN];
163 } MH_dat;
164 } MH;
165 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */
166 } M_dat;
167};
168#define m_next m_hdr.mh_next
169#define m_len m_hdr.mh_len
170#define m_data m_hdr.mh_data
171#define m_type m_hdr.mh_type
172#define m_flags m_hdr.mh_flags
173#define m_nextpkt m_hdr.mh_nextpkt
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174#define m_pkthdr M_dat.MH.MH_pkthdr
175#define m_ext M_dat.MH.MH_dat.MH_ext
176#define m_pktdat M_dat.MH.MH_dat.MH_databuf
177#define m_dat M_dat.M_databuf
178
179/*
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180 * Code that uses m_act should be converted to use m_nextpkt
181 * instead; m_act is historical and deprecated.
182 */
183#define m_act m_nextpkt
184
185/*
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186 * mbuf flags.
187 */
188#define M_EXT 0x0001 /* has associated external storage */
189#define M_PKTHDR 0x0002 /* start of record */
190#define M_EOR 0x0004 /* end of record */
191#define M_PROTO1 0x0008 /* protocol-specific */
192#define M_PROTO2 0x0010 /* protocol-specific */
193#define M_PROTO3 0x0020 /* protocol-specific */
194#define M_PROTO4 0x0040 /* protocol-specific */
195#define M_PROTO5 0x0080 /* protocol-specific */
196
197/*
198 * mbuf pkthdr flags (also stored in m_flags).
199 */
200#define M_BCAST 0x0100 /* send/received as link-level broadcast */
201#define M_MCAST 0x0200 /* send/received as link-level multicast */
202#define M_FRAG 0x0400 /* packet is a fragment of a larger packet */
203#define M_FIRSTFRAG 0x0800 /* packet is first fragment */
204#define M_LASTFRAG 0x1000 /* packet is last fragment */
77e294a1 205#define M_CLCACHE 0x2000 /* mbuf allocated from the cluster cache */
90775e29 206#define M_EXT_CLUSTER 0x4000 /* standard cluster else special */
77e294a1 207#define M_PHCACHE 0x8000 /* mbuf allocated from the pkt header cache */
78812139 208#define M_NOTIFICATION 0x10000 /* notification event */
83790f85 209#define M_VLANTAG 0x20000 /* ether_vlantag is valid */
cb8d752c 210#define M_MPLSLABELED 0x40000 /* packet is mpls labeled */
8697599b 211#define M_LENCHECKED 0x80000 /* packet proto lengths are checked */
6afb09f8 212#define M_HASH 0x100000/* hash field in pkthdr is valid */
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213#define M_PROTO6 0x200000/* protocol-specific */
214#define M_PROTO7 0x400000/* protocol-specific */
215#define M_PROTO8 0x800000/* protocol-specific */
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216
217/*
218 * Flags copied when copying m_pkthdr.
219 */
ee42237d 220#define M_COPYFLAGS (M_PKTHDR|M_EOR|M_PROTO1|M_PROTO2|M_PROTO3 | \
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221 M_PROTO4|M_PROTO5|M_PROTO6|M_PROTO7|M_PROTO8 | \
222 M_BCAST|M_MCAST|M_FRAG|M_FIRSTFRAG|M_LASTFRAG | \
223 M_VLANTAG|M_MPLSLABELED | \
6afb09f8 224 M_LENCHECKED|M_HASH)
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225
226/*
227 * Flags indicating hw checksum support and sw checksum requirements.
228 */
229#define CSUM_IP 0x0001 /* will csum IP */
230#define CSUM_TCP 0x0002 /* will csum TCP */
231#define CSUM_UDP 0x0004 /* will csum UDP */
232#define CSUM_IP_FRAGS 0x0008 /* will csum IP fragments */
233#define CSUM_FRAGMENT 0x0010 /* will do IP fragmentation */
234
235#define CSUM_IP_CHECKED 0x0100 /* did csum IP */
236#define CSUM_IP_VALID 0x0200 /* ... the csum is valid */
237#define CSUM_DATA_VALID 0x0400 /* csum_data field is valid */
238#define CSUM_PSEUDO_HDR 0x0800 /* csum_data has pseudo hdr */
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239#define CSUM_FRAG_NOT_CHECKED 0x1000 /* did _not_ csum fragment
240 * NB: This flag is only used
241 * by IP defragmenter.
242 */
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243
244#define CSUM_DELAY_DATA (CSUM_TCP | CSUM_UDP)
245#define CSUM_DELAY_IP (CSUM_IP) /* XXX add ipv6 here too? */
246
247/*
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248 * Flags indicating PF processing status
249 */
f2c2ec09 250#define FW_MBUF_GENERATED 0x00000001
70224baa 251#define XX_MBUF_UNUSED02 0x00000002
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252#define PF_MBUF_ROUTED 0x00000004 /* pf_routed field is valid */
253#define PF_MBUF_TRANSLATE_LOCALHOST \
254 0x00000008
255#define PF_MBUF_FRAGCACHE 0x00000010
70224baa 256#define XX_MBUF_UNUSED20 0x00000020
5de23090 257#define IPFORWARD_MBUF_TAGGED 0x00000040
84a3e25a 258#define DUMMYNET_MBUF_TAGGED 0x00000080
5950bf01 259#define ALTQ_MBUF_STATE_HASHED 0x00000100
012d335d 260#define FW_MBUF_REDISPATCH 0x00000200
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261#define PF_MBUF_GENERATED FW_MBUF_GENERATED
262#define IPFW_MBUF_GENERATED FW_MBUF_GENERATED
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263
264/*
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265 * The PF code uses a different symbol name for the m_tag. This is
266 * NOT a pkthdr flag.
267 */
268#define PF_MBUF_TAGGED PACKET_TAG_PF
269
270/*
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271 * mbuf types.
272 */
273#define MT_FREE 0 /* should be on free list */
274#define MT_DATA 1 /* dynamic (data) allocation */
275#define MT_HEADER 2 /* packet header */
60ed1291 276#define MT_SONAME 3 /* socket name */
5de23090 277/* 4 was MT_TAG */
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278#define MT_CONTROL 5 /* extra-data protocol message */
279#define MT_OOBDATA 6 /* expedited data */
280#define MT_NTYPES 7 /* number of mbuf types for mbtypes[] */
984263bc 281
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282struct mbuf_chain {
283 struct mbuf *mc_head;
284 struct mbuf *mc_tail;
285};
286
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287/*
288 * General mbuf allocator statistics structure.
289 */
290struct mbstat {
291 u_long m_mbufs; /* mbufs obtained from page pool */
292 u_long m_clusters; /* clusters obtained from page pool */
293 u_long m_spare; /* spare field */
294 u_long m_clfree; /* free clusters */
295 u_long m_drops; /* times failed to find space */
296 u_long m_wait; /* times waited for space */
297 u_long m_drain; /* times drained protocols for space */
298 u_long m_mcfail; /* times m_copym failed */
299 u_long m_mpfail; /* times m_pullup failed */
300 u_long m_msize; /* length of an mbuf */
301 u_long m_mclbytes; /* length of an mbuf cluster */
302 u_long m_minclsize; /* min length of data to allocate a cluster */
303 u_long m_mlen; /* length of data in an mbuf */
304 u_long m_mhlen; /* length of data in a header mbuf */
305};
306
307/*
308 * Flags specifying how an allocation should be made.
309 */
310
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311#define MB_DONTWAIT 0x4
312#define MB_TRYWAIT 0x8
313#define MB_WAIT MB_TRYWAIT
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314
315/*
316 * Mbuf to Malloc Flag Conversion.
317 */
74f1caca 318#define MBTOM(how) ((how) & MB_TRYWAIT ? M_WAITOK : M_NOWAIT)
984263bc 319
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320/*
321 * These are identifying numbers passed to the m_mballoc_wait function,
322 * allowing us to determine whether the call came from an MGETHDR or
323 * an MGET.
324 */
325#define MGETHDR_C 1
326#define MGET_C 2
327
328/*
12496bdf 329 * mbuf allocation/deallocation macros (YYY deprecated, too big):
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330 *
331 * MGET(struct mbuf *m, int how, int type)
332 * allocates an mbuf and initializes it to contain internal data.
333 *
334 * MGETHDR(struct mbuf *m, int how, int type)
335 * allocates an mbuf and initializes it to contain a packet header
336 * and internal data.
337 */
338#define MGET(m, how, type) do { \
12496bdf 339 (m) = m_get((how), (type)); \
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340} while (0)
341
342#define MGETHDR(m, how, type) do { \
12496bdf 343 (m) = m_gethdr((how), (type)); \
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344} while (0)
345
346/*
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347 * MCLGET adds such clusters to a normal mbuf. The flag M_EXT is set upon
348 * success.
50503f0f 349 * Deprecated. Use m_getcl() or m_getl() instead.
984263bc 350 */
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351#define MCLGET(m, how) do { \
352 m_mclget((m), (how)); \
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353} while (0)
354
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355/*
356 * NB: M_COPY_PKTHDR is deprecated; use either M_MOVE_PKTHDR
357 * or m_dup_pkthdr.
358 */
359/*
360 * Move mbuf pkthdr from "from" to "to".
361 * from should have M_PKTHDR set, and to must be empty.
362 * from no longer has a pkthdr after this operation.
363 */
364#define M_MOVE_PKTHDR(_to, _from) m_move_pkthdr((_to), (_from))
365
366/*
367 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
368 * an object of the specified size at the end of the mbuf, longword aligned.
369 */
370#define M_ALIGN(m, len) do { \
371 (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1); \
372} while (0)
373
374/*
375 * As above, for mbufs allocated with m_gethdr/MGETHDR
376 * or initialized by M_COPY_PKTHDR.
377 */
378#define MH_ALIGN(m, len) do { \
379 (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1); \
380} while (0)
381
382/*
383 * Check if we can write to an mbuf.
384 */
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385#define M_EXT_WRITABLE(m) (m_sharecount(m) == 1)
386#define M_WRITABLE(m) (!((m)->m_flags & M_EXT) || M_EXT_WRITABLE(m))
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387
388/*
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389 * Check if the supplied mbuf has a packet header, or else panic.
390 */
391#define M_ASSERTPKTHDR(m) \
392 KASSERT(m != NULL && m->m_flags & M_PKTHDR, \
393 ("%s: invalid mbuf or no mbuf packet header!", __func__))
394
395/*
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396 * Compute the amount of space available before the current start of data.
397 * The M_EXT_WRITABLE() is a temporary, conservative safety measure: the burden
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398 * of checking writability of the mbuf data area rests solely with the caller.
399 */
400#define M_LEADINGSPACE(m) \
401 ((m)->m_flags & M_EXT ? \
402 (M_EXT_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0): \
403 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \
404 (m)->m_data - (m)->m_dat)
405
406/*
7b6f875f 407 * Compute the amount of space available after the end of data in an mbuf.
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408 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
409 * of checking writability of the mbuf data area rests solely with the caller.
410 */
411#define M_TRAILINGSPACE(m) \
412 ((m)->m_flags & M_EXT ? \
413 (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size \
414 - ((m)->m_data + (m)->m_len) : 0) : \
415 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
416
417/*
418 * Arrange to prepend space of size plen to mbuf m.
419 * If a new mbuf must be allocated, how specifies whether to wait.
74f1caca 420 * If how is MB_DONTWAIT and allocation fails, the original mbuf chain
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421 * is freed and m is set to NULL.
422 */
423#define M_PREPEND(m, plen, how) do { \
424 struct mbuf **_mmp = &(m); \
425 struct mbuf *_mm = *_mmp; \
426 int _mplen = (plen); \
427 int __mhow = (how); \
428 \
429 if (M_LEADINGSPACE(_mm) >= _mplen) { \
430 _mm->m_data -= _mplen; \
431 _mm->m_len += _mplen; \
432 } else \
433 _mm = m_prepend(_mm, _mplen, __mhow); \
434 if (_mm != NULL && _mm->m_flags & M_PKTHDR) \
435 _mm->m_pkthdr.len += _mplen; \
436 *_mmp = _mm; \
437} while (0)
438
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439/* Length to m_copy to copy all. */
440#define M_COPYALL 1000000000
441
442/* Compatibility with 4.3 */
74f1caca 443#define m_copy(m, o, l) m_copym((m), (o), (l), MB_DONTWAIT)
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444
445#ifdef _KERNEL
446extern u_int m_clalloc_wid; /* mbuf cluster wait count */
447extern u_int m_mballoc_wid; /* mbuf wait count */
448extern int max_linkhdr; /* largest link-level header */
449extern int max_protohdr; /* largest protocol header */
450extern int max_hdr; /* largest link+protocol header */
451extern int max_datalen; /* MHLEN - max_hdr */
984263bc 452extern int mbuf_wait; /* mbuf sleep time */
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453extern int nmbclusters;
454extern int nmbufs;
984263bc 455
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456struct uio;
457
984263bc 458void m_adj(struct mbuf *, int);
b40798b4 459void m_align(struct mbuf *, int);
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460int m_apply(struct mbuf *, int, int,
461 int (*)(void *, void *, u_int), void *);
bf2cc98c 462int m_append(struct mbuf *, int, c_caddr_t);
984263bc 463void m_cat(struct mbuf *, struct mbuf *);
df80f2ea 464u_int m_countm(struct mbuf *m, struct mbuf **lastm, u_int *mbcnt);
984263bc 465void m_copyback(struct mbuf *, int, int, caddr_t);
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466void m_copydata(const struct mbuf *, int, int, caddr_t);
467struct mbuf *m_copym(const struct mbuf *, int, int, int);
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468struct mbuf *m_copypacket(struct mbuf *, int);
469struct mbuf *m_defrag(struct mbuf *, int);
c8f5127a 470struct mbuf *m_defrag_nofree(struct mbuf *, int);
984263bc 471struct mbuf *m_devget(char *, int, int, struct ifnet *,
50503f0f 472 void (*copy)(volatile const void *, volatile void *, size_t));
984263bc 473struct mbuf *m_dup(struct mbuf *, int);
3bf6fec3 474struct mbuf *m_dup_data(struct mbuf *, int);
f15db79e 475int m_dup_pkthdr(struct mbuf *, const struct mbuf *, int);
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476struct mbuf *m_free(struct mbuf *);
477void m_freem(struct mbuf *);
478struct mbuf *m_get(int, int);
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479struct mbuf *m_getc(int len, int how, int type);
480struct mbuf *m_getcl(int how, short type, int flags);
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481struct mbuf *m_getclr(int, int);
482struct mbuf *m_gethdr(int, int);
483struct mbuf *m_getm(struct mbuf *, int, int, int);
920c9f10 484struct mbuf *m_getptr(struct mbuf *, int, int *);
50503f0f 485struct mbuf *m_last(struct mbuf *m);
df80f2ea 486u_int m_lengthm(struct mbuf *m, struct mbuf **lastm);
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487void m_move_pkthdr(struct mbuf *, struct mbuf *);
488struct mbuf *m_prepend(struct mbuf *, int, int);
489void m_print(const struct mbuf *m);
490struct mbuf *m_pulldown(struct mbuf *, int, int, int *);
491struct mbuf *m_pullup(struct mbuf *, int);
984263bc 492struct mbuf *m_split(struct mbuf *, int, int);
e12241e1 493struct mbuf *m_uiomove(struct uio *);
b6650ec0 494void m_mclget(struct mbuf *m, int how);
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495int m_sharecount(struct mbuf *m);
496void m_chtype(struct mbuf *m, int type);
cf12ba3c 497int m_devpad(struct mbuf *m, int padto);
90775e29 498
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499#ifdef MBUF_DEBUG
500void mbuftrackid(struct mbuf *, int);
501#else
502#define mbuftrackid(m, id) /* empty */
503#endif
504
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505/*
506 * Allocate the right type of mbuf for the desired total length.
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507 * The mbuf returned does not necessarily cover the entire requested length.
508 * This function follows mbuf chaining policy of allowing MINCLSIZE
509 * amount of chained mbufs.
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510 */
511static __inline struct mbuf *
512m_getl(int len, int how, int type, int flags, int *psize)
513{
514 struct mbuf *m;
515 int size;
516
517 if (len >= MINCLSIZE) {
518 m = m_getcl(how, type, flags);
519 size = MCLBYTES;
520 } else if (flags & M_PKTHDR) {
521 m = m_gethdr(how, type);
522 size = MHLEN;
523 } else {
524 m = m_get(how, type);
525 size = MLEN;
526 }
527 if (psize != NULL)
528 *psize = size;
529 return (m);
530}
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531
532/*
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533 * Get a single mbuf that covers the requested number of bytes.
534 * This function does not create mbuf chains. It explicitly marks
535 * places in the code that abuse mbufs for contiguous data buffers.
536 */
537static __inline struct mbuf *
538m_getb(int len, int how, int type, int flags)
539{
540 struct mbuf *m;
541 int mbufsize = (flags & M_PKTHDR) ? MHLEN : MLEN;
542
543 if (len > mbufsize)
544 m = m_getcl(how, type, flags);
545 else if (flags & M_PKTHDR)
546 m = m_gethdr(how, type);
547 else
548 m = m_get(how, type);
549 return (m);
550}
551
552/*
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553 * Packets may have annotations attached by affixing a list
554 * of "packet tags" to the pkthdr structure. Packet tags are
555 * dynamically allocated semi-opaque data structures that have
556 * a fixed header (struct m_tag) that specifies the size of the
557 * memory block and a <cookie,type> pair that identifies it.
558 * The cookie is a 32-bit unique unsigned value used to identify
559 * a module or ABI. By convention this value is chose as the
560 * date+time that the module is created, expressed as the number of
561 * seconds since the epoch (e.g. using date -u +'%s'). The type value
562 * is an ABI/module-specific value that identifies a particular annotation
563 * and is private to the module. For compatibility with systems
564 * like openbsd that define packet tags w/o an ABI/module cookie,
565 * the value PACKET_ABI_COMPAT is used to implement m_tag_get and
566 * m_tag_find compatibility shim functions and several tag types are
567 * defined below. Users that do not require compatibility should use
568 * a private cookie value so that packet tag-related definitions
569 * can be maintained privately.
570 *
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571 * Note that the packet tag returned by m_tag_alloc has the default
572 * memory alignment implemented by kmalloc. To reference private data
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573 * one can use a construct like:
574 *
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575 * struct m_tag *mtag = m_tag_alloc(...);
576 * struct foo *p = m_tag_data(mtag);
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577 *
578 * if the alignment of struct m_tag is sufficient for referencing members
579 * of struct foo. Otherwise it is necessary to embed struct m_tag within
580 * the private data structure to insure proper alignment; e.g.
581 *
582 * struct foo {
583 * struct m_tag tag;
584 * ...
585 * };
4c7020ad 586 * struct foo *p = (struct foo *)m_tag_alloc(...);
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587 * struct m_tag *mtag = &p->tag;
588 */
589
590#define PACKET_TAG_NONE 0 /* Nadda */
591
592/* Packet tag for use with PACKET_ABI_COMPAT */
593#define PACKET_TAG_IPSEC_IN_DONE 1 /* IPsec applied, in */
821819dc 594/* struct tdb_indent */
984263bc 595#define PACKET_TAG_IPSEC_OUT_DONE 2 /* IPsec applied, out */
821819dc 596/* struct tdb_indent */
984263bc 597#define PACKET_TAG_IPSEC_IN_CRYPTO_DONE 3 /* NIC IPsec crypto done */
821819dc 598/* struct tdb_indent, never added */
984263bc 599#define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED 4 /* NIC IPsec crypto req'ed */
821819dc 600/* struct tdb_indent, never added */
ba3a125b 601#define PACKET_TAG_IPSEC_PENDING_TDB 5 /* Reminder to do IPsec */
821819dc 602/* struct tdb_indent, never added */
ba3a125b 603#define PACKET_TAG_ENCAP 6 /* Encap. processing */
821819dc 604/* struct ifnet *, the GIF interface */
ba3a125b 605#define PACKET_TAG_IPSEC_HISTORY 7 /* IPSEC history */
821819dc 606/* struct ipsec_history */
ba3a125b 607#define PACKET_TAG_IPV6_INPUT 8 /* IPV6 input processing */
821819dc 608/* struct ip6aux */
e5ecc832 609#define PACKET_TAG_IPFW_DIVERT 9 /* divert info */
68edaf54 610/* struct divert_info */
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611#define PACKET_TAG_DUMMYNET 15 /* dummynet info */
612/* struct dn_pkt */
984263bc 613#define PACKET_TAG_IPFORWARD 18 /* ipforward info */
5de23090 614/* struct sockaddr_in */
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615#define PACKET_TAG_IPSRCRT 27 /* IP srcrt opts */
616/* struct ip_srcrt_opt */
5de23090 617#define PACKET_TAG_CARP 28 /* CARP info */
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618/* struct pf_mtag */
619#define PACKET_TAG_PF 29 /* PF info */
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620
621/* Packet tag routines */
622struct m_tag *m_tag_alloc(u_int32_t, int, int, int);
623void m_tag_free(struct m_tag *);
624void m_tag_prepend(struct mbuf *, struct m_tag *);
625void m_tag_unlink(struct mbuf *, struct m_tag *);
626void m_tag_delete(struct mbuf *, struct m_tag *);
7b6f875f 627void m_tag_delete_chain(struct mbuf *);
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628struct m_tag *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
629struct m_tag *m_tag_copy(struct m_tag *, int);
f15db79e 630int m_tag_copy_chain(struct mbuf *, const struct mbuf *, int);
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631void m_tag_init(struct mbuf *);
632struct m_tag *m_tag_first(struct mbuf *);
633struct m_tag *m_tag_next(struct mbuf *, struct m_tag *);
634
635/* these are for openbsd compatibility */
636#define MTAG_ABI_COMPAT 0 /* compatibility ABI */
637
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638static __inline void *
639m_tag_data(struct m_tag *tag)
640{
641 return ((void *)(tag + 1));
642}
643
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644static __inline struct m_tag *
645m_tag_get(int type, int length, int wait)
646{
647 return m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait);
648}
649
650static __inline struct m_tag *
651m_tag_find(struct mbuf *m, int type, struct m_tag *start)
652{
653 return m_tag_locate(m, MTAG_ABI_COMPAT, type, start);
654}
984263bc 655
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656#endif /* _KERNEL */
657
658#endif /* _KERNEL || _KERNEL_STRUCTURES */
659#endif /* !_SYS_MBUF_H_ */