1/* $OpenBSD: mbuf.h,v 1.269 2026/02/05 03:26:00 dlg Exp $ */
2/* $NetBSD: mbuf.h,v 1.19 1996/02/09 18:25:14 christos Exp $ */
3
4/*
5 * Copyright (c) 1982, 1986, 1988, 1993
6 * The Regents of the University of California. 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 */
34
35#ifndef _SYS_MBUF_H_
36#define _SYS_MBUF_H_
37
38#include <sys/queue.h>
39
40/*
41 * Constants related to network buffer management.
42 * MCLBYTES must be no larger than PAGE_SIZE (the software page size) and,
43 * on machines that exchange pages of input or output buffers with mbuf
44 * clusters (MAPPED_MBUFS), MCLBYTES must also be an integral multiple
45 * of the hardware page size.
46 */
47#define MSIZE 256 /* size of an mbuf */
48
49/*
50 * Mbufs are of a single size, MSIZE, which includes overhead. An mbuf may
51 * add a single "mbuf cluster" of size MCLBYTES, which has no additional
52 * overhead and is used instead of the internal data area; this is done when
53 * at least MINCLSIZE of data must be stored.
54 */
55
56#define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */
57#define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */
58
59#define MAXMCLBYTES (64 * 1024) /* largest cluster from the stack */
60#define MINCLSIZE (MHLEN + MLEN + 1) /* smallest amount to put in cluster */
61
62#define MCLSHIFT 11 /* convert bytes to m_buf clusters */
63 /* 2K cluster can hold Ether frame */
64#define MCLBYTES (1 << MCLSHIFT) /* size of a m_buf cluster */
65
66/* Packet tags structure */
67struct m_tag {
68 SLIST_ENTRY(m_tag) m_tag_link; /* List of packet tags */
69 u_int16_t m_tag_id; /* Tag ID */
70 u_int16_t m_tag_len; /* Length of data */
71};
72
73/*
74 * Macros for type conversion
75 * mtod(m,t) - convert mbuf pointer to data pointer of correct type
76 */
77#define mtod(m,t) ((t)((m)->m_data))
78
79/* header at beginning of each mbuf: */
80struct m_hdr {
81 struct mbuf *mh_next; /* next buffer in chain */
82 struct mbuf *mh_nextpkt; /* next chain in queue/record */
83 caddr_t mh_data; /* location of data */
84 u_int mh_len; /* amount of data in this mbuf */
85 short mh_type; /* type of data in this mbuf */
86 u_short mh_flags; /* flags; see below */
87#ifndef __LP64__
88 u_int mh_pad; /* pad to 8-byte boundary */
89#endif
90};
91
92/* pf stuff */
93struct pf_state_key;
94struct inpcb;
95
96struct pkthdr_pf {
97 struct pf_state_key *statekey; /* pf stackside statekey */
98 struct inpcb *inp; /* connected pcb for outgoing packet */
99 u_int32_t qid; /* queue id */
100 u_int16_t tag; /* tag id */
101 u_int16_t delay; /* delay packet by X ms */
102 u_int8_t flags;
103 u_int8_t routed;
104 u_int8_t prio;
105 u_int8_t pad[1];
106};
107
108/* pkthdr_pf.flags */
109#define PF_TAG_GENERATED 0x01
110#define PF_TAG_SYNCOOKIE_RECREATED 0x02
111#define PF_TAG_TRANSLATE_LOCALHOST 0x04
112#define PF_TAG_DIVERTED 0x08
113#define PF_TAG_DIVERTED_PACKET 0x10
114#define PF_TAG_REROUTE 0x20
115#define PF_TAG_REFRAGMENTED 0x40 /* refragmented ipv6 packet */
116#define PF_TAG_PROCESSED 0x80 /* packet was checked by pf */
117
118#ifdef _KERNEL
119#define MPF_BITS \
120 ("\20\1GENERATED\2SYNCOOKIE_RECREATED\3TRANSLATE_LOCALHOST\4DIVERTED" \
121 "\5DIVERTED_PACKET\6REROUTE\7REFRAGMENTED\10PROCESSED")
122#endif
123
124/* record/packet header in first mbuf of chain; valid if M_PKTHDR set */
125struct pkthdr {
126 void *ph_cookie; /* additional data */
127 SLIST_HEAD(, m_tag) ph_tags; /* list of packet tags */
128 int64_t ph_timestamp; /* packet timestamp */
129 int len; /* total packet length */
130 u_int ph_rtableid; /* routing table id */
131 u_int ph_ifidx; /* rcv interface index */
132 u_int16_t ph_tagsset; /* mtags attached */
133 u_int16_t ph_flowid; /* pseudo unique flow id */
134 u_int16_t csum_flags; /* checksum flags */
135 u_int16_t ether_vtag; /* Ethernet 802.1p+Q vlan tag */
136 u_int16_t ph_mss; /* TCP max segment size */
137 u_int8_t ph_loopcnt; /* mbuf is looping in kernel */
138 u_int8_t ph_family; /* af, used when queueing */
139 struct pkthdr_pf pf;
140};
141
142/* description of external storage mapped into mbuf, valid if M_EXT set */
143struct mbuf_ext {
144 caddr_t ext_buf; /* start of buffer */
145 void *ext_arg;
146 u_int ext_free_fn; /* index of free function */
147 u_int ext_size; /* size of buffer, for ext_free_fn */
148 struct mbuf *ext_nextref;
149 struct mbuf *ext_prevref;
150#ifdef DEBUG
151 const char *ext_ofile;
152 const char *ext_nfile;
153 int ext_oline;
154 int ext_nline;
155#endif
156};
157
158struct mbuf {
159 struct m_hdr m_hdr;
160 union {
161 struct {
162 struct pkthdr MH_pkthdr; /* M_PKTHDR set */
163 union {
164 struct mbuf_ext MH_ext; /* M_EXT set */
165 char MH_databuf[MHLEN];
166 } MH_dat;
167 } MH;
168 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */
169 } M_dat;
170};
171#define m_next m_hdr.mh_next
172#define m_len m_hdr.mh_len
173#define m_data m_hdr.mh_data
174#define m_type m_hdr.mh_type
175#define m_flags m_hdr.mh_flags
176#define m_nextpkt m_hdr.mh_nextpkt
177#define m_pkthdr M_dat.MH.MH_pkthdr
178#define m_ext M_dat.MH.MH_dat.MH_ext
179#define m_pktdat M_dat.MH.MH_dat.MH_databuf
180#define m_dat M_dat.M_databuf
181
182/* mbuf flags */
183#define M_EXT 0x0001 /* has associated external storage */
184#define M_PKTHDR 0x0002 /* start of record */
185#define M_EOR 0x0004 /* end of record */
186#define M_EXTWR 0x0008 /* external storage is writable */
187#define M_PROTO1 0x0010 /* protocol-specific */
188
189/* mbuf pkthdr flags, also in m_flags */
190#define M_VLANTAG 0x0020 /* ether_vtag is valid */
191#define M_LOOP 0x0040 /* packet has been sent from local machine */
192#define M_BCAST 0x0100 /* sent/received as link-level broadcast */
193#define M_MCAST 0x0200 /* sent/received as link-level multicast */
194#define M_CONF 0x0400 /* payload was encrypted (ESP-transport) */
195#define M_AUTH 0x0800 /* payload was authenticated (AH or ESP auth) */
196#define M_TUNNEL 0x1000 /* IP-in-IP added by tunnel mode IPsec */
197#define M_ZEROIZE 0x2000 /* Zeroize data part on free */
198#define M_COMP 0x4000 /* header was decompressed */
199#define M_LINK0 0x8000 /* link layer specific flag */
200
201#ifdef _KERNEL
202#define M_BITS \
203 ("\20\1M_EXT\2M_PKTHDR\3M_EOR\4M_EXTWR\5M_PROTO1\6M_VLANTAG\7M_LOOP" \
204 "\11M_BCAST\12M_MCAST\13M_CONF\14M_AUTH\15M_TUNNEL" \
205 "\16M_ZEROIZE\17M_COMP\20M_LINK0")
206#endif
207
208/* flags copied when copying m_pkthdr */
209#define M_COPYFLAGS (M_PKTHDR|M_EOR|M_PROTO1|M_BCAST|M_MCAST|M_CONF|M_COMP|\
210 M_AUTH|M_LOOP|M_TUNNEL|M_LINK0|M_VLANTAG|M_ZEROIZE)
211
212/* Checksumming flags */
213#define M_IPV4_CSUM_OUT 0x0001 /* IPv4 checksum needed */
214#define M_TCP_CSUM_OUT 0x0002 /* TCP checksum needed */
215#define M_UDP_CSUM_OUT 0x0004 /* UDP checksum needed */
216#define M_IPV4_CSUM_IN_OK 0x0008 /* IPv4 checksum verified */
217#define M_IPV4_CSUM_IN_BAD 0x0010 /* IPv4 checksum bad */
218#define M_TCP_CSUM_IN_OK 0x0020 /* TCP checksum verified */
219#define M_TCP_CSUM_IN_BAD 0x0040 /* TCP checksum bad */
220#define M_UDP_CSUM_IN_OK 0x0080 /* UDP checksum verified */
221#define M_UDP_CSUM_IN_BAD 0x0100 /* UDP checksum bad */
222#define M_ICMP_CSUM_OUT 0x0200 /* ICMP/ICMPv6 checksum needed */
223#define M_ICMP_CSUM_IN_OK 0x0400 /* ICMP/ICMPv6 checksum verified */
224#define M_ICMP_CSUM_IN_BAD 0x0800 /* ICMP/ICMPv6 checksum bad */
225#define M_IPV6_DF_OUT 0x1000 /* don't fragment outgoing IPv6 */
226#define M_TIMESTAMP 0x2000 /* ph_timestamp is set */
227#define M_FLOWID 0x4000 /* ph_flowid is set */
228#define M_TCP_TSO 0x8000 /* TCP Segmentation Offload needed */
229
230#ifdef _KERNEL
231#define MCS_BITS \
232 ("\20\1IPV4_CSUM_OUT\2TCP_CSUM_OUT\3UDP_CSUM_OUT\4IPV4_CSUM_IN_OK" \
233 "\5IPV4_CSUM_IN_BAD\6TCP_CSUM_IN_OK\7TCP_CSUM_IN_BAD\10UDP_CSUM_IN_OK" \
234 "\11UDP_CSUM_IN_BAD\12ICMP_CSUM_OUT\13ICMP_CSUM_IN_OK\14ICMP_CSUM_IN_BAD" \
235 "\15IPV6_NODF_OUT" "\16TIMESTAMP" "\17FLOWID" "\20TCP_TSO")
236#endif
237
238/* mbuf types */
239#define MT_FREE 0 /* should be on free list */
240#define MT_DATA 1 /* dynamic (data) allocation */
241#define MT_HEADER 2 /* packet header */
242#define MT_SONAME 3 /* socket name */
243#define MT_SOOPTS 4 /* socket options */
244#define MT_FTABLE 5 /* fragment reassembly header */
245#define MT_CONTROL 6 /* extra-data protocol message */
246#define MT_OOBDATA 7 /* expedited data */
247#define MT_NTYPES 8
248
249/* flags to m_get/MGET */
250#include <sys/malloc.h>
251#define M_DONTWAIT M_NOWAIT
252#define M_WAIT M_WAITOK
253
254/*
255 * mbuf allocation/deallocation macros:
256 *
257 * MGET(struct mbuf *m, int how, int type)
258 * allocates an mbuf and initializes it to contain internal data.
259 *
260 * MGETHDR(struct mbuf *m, int how, int type)
261 * allocates an mbuf and initializes it to contain a packet header
262 * and internal data.
263 */
264#define MGET(m, how, type) m = m_get((how), (type))
265
266#define MGETHDR(m, how, type) m = m_gethdr((how), (type))
267
268/*
269 * Macros for tracking external storage associated with an mbuf.
270 */
271#ifdef DEBUG
272#define MCLREFDEBUGN(m, file, line) do { \
273 (m)->m_ext.ext_nfile = (file); \
274 (m)->m_ext.ext_nline = (line); \
275 } while (/* CONSTCOND */ 0)
276#define MCLREFDEBUGO(m, file, line) do { \
277 (m)->m_ext.ext_ofile = (file); \
278 (m)->m_ext.ext_oline = (line); \
279 } while (/* CONSTCOND */ 0)
280#else
281#define MCLREFDEBUGN(m, file, line)
282#define MCLREFDEBUGO(m, file, line)
283#endif
284
285#define MCLISREFERENCED(m) ((m)->m_ext.ext_nextref != (m))
286
287#define MCLADDREFERENCE(o, n) m_extref((o), (n))
288
289#define MCLINITREFERENCE(m) do { \
290 (m)->m_ext.ext_prevref = (m); \
291 (m)->m_ext.ext_nextref = (m); \
292 MCLREFDEBUGO((m), __FILE__, __LINE__); \
293 MCLREFDEBUGN((m), NULL, 0); \
294 } while (/* CONSTCOND */ 0)
295
296/*
297 * Macros for mbuf external storage.
298 *
299 * MEXTADD adds pre-allocated external storage to
300 * a normal mbuf; the flag M_EXT is set.
301 *
302 * MCLGET allocates and adds an mbuf cluster to a normal mbuf;
303 * the flag M_EXT is set upon success.
304 */
305#define MEXTADD(m, buf, size, mflags, freefn, arg) do { \
306 (m)->m_data = (m)->m_ext.ext_buf = (caddr_t)(buf); \
307 (m)->m_flags |= M_EXT | (mflags & M_EXTWR); \
308 (m)->m_ext.ext_size = (size); \
309 (m)->m_ext.ext_free_fn = (freefn); \
310 (m)->m_ext.ext_arg = (arg); \
311 MCLINITREFERENCE(m); \
312} while (/* CONSTCOND */ 0)
313
314#define MCLGET(m, how) (void) m_clget((m), (how), MCLBYTES)
315#define MCLGETL(m, how, l) m_clget((m), (how), (l))
316
317u_int mextfree_register(void (*)(caddr_t, u_int, void *));
318#define MEXTFREE_POOL 0
319
320/*
321 * Move just m_pkthdr from from to to,
322 * remove M_PKTHDR and clean flags/tags for from.
323 */
324#define M_MOVE_HDR(to, from) do { \
325 (to)->m_pkthdr = (from)->m_pkthdr; \
326 (from)->m_flags &= ~M_PKTHDR; \
327 SLIST_INIT(&(from)->m_pkthdr.ph_tags); \
328 (from)->m_pkthdr.pf.statekey = NULL; \
329} while (/* CONSTCOND */ 0)
330
331/*
332 * MOVE mbuf pkthdr from from to to.
333 * from must have M_PKTHDR set, and to must be empty.
334 */
335#define M_MOVE_PKTHDR(to, from) do { \
336 (to)->m_flags = ((to)->m_flags & (M_EXT | M_EXTWR)); \
337 (to)->m_flags |= (from)->m_flags & M_COPYFLAGS; \
338 M_MOVE_HDR((to), (from)); \
339 if (((to)->m_flags & M_EXT) == 0) \
340 (to)->m_data = (to)->m_pktdat; \
341} while (/* CONSTCOND */ 0)
342
343/*
344 * Determine if an mbuf's data area is read-only. This is true for
345 * non-cluster external storage and for clusters that are being
346 * referenced by more than one mbuf.
347 */
348#define M_READONLY(m) \
349 (((m)->m_flags & M_EXT) != 0 && \
350 (((m)->m_flags & M_EXTWR) == 0 || MCLISREFERENCED(m)))
351
352/*
353 * Arrange to prepend space of size plen to mbuf m.
354 * If a new mbuf must be allocated, how specifies whether to wait.
355 * If how is M_DONTWAIT and allocation fails, the original mbuf chain
356 * is freed and m is set to NULL.
357 */
358#define M_PREPEND(m, plen, how) \
359 (m) = m_prepend((m), (plen), (how))
360
361/* length to m_copy to copy all */
362#define M_COPYALL 1000000000
363
364enum mbstat_counters {
365 mbs_drops = MT_NTYPES,
366 mbs_wait,
367 mbs_drain,
368 mbs_defrag_alloc,
369 mbs_prepend_alloc,
370 mbs_pullup_alloc,
371 mbs_pullup_copy,
372 mbs_pulldown_alloc,
373 mbs_pulldown_copy,
374 mbs_ncounters
375};
376
377/*
378 * Mbuf statistics.
379 * For statistics related to mbuf and cluster allocations, see also the
380 * pool headers (mbpool and mclpool).
381 */
382struct mbstat {
383 u_long m_drops; /* times failed to find space */
384 u_long m_wait; /* times waited for space */
385 u_long m_drain; /* times drained protocols for space */
386 u_long m_mtypes[MT_NTYPES]; /* type specific mbuf allocations */
387 u_long m_defrag_alloc;
388 u_long m_prepend_alloc;
389 u_long m_pullup_alloc;
390 u_long m_pullup_copy;
391 u_long m_pulldown_alloc;
392 u_long m_pulldown_copy;
393};
394
395#include <sys/mutex.h>
396
397struct mbuf_list {
398 struct mbuf *ml_head;
399 struct mbuf *ml_tail;
400 u_int ml_len;
401};
402
403struct mbuf_queue {
404 struct mutex mq_mtx;
405 struct mbuf_list mq_list;
406 u_int mq_maxlen;
407 u_int mq_drops;
408};
409
410#ifdef _KERNEL
411struct pool;
412
413extern long nmbclust; /* limit on the # of clusters */
414extern int max_linkhdr; /* largest link-level header */
415extern int max_protohdr; /* largest protocol header */
416extern int max_hdr; /* largest link+protocol header */
417extern struct cpumem *mbstat; /* mbuf statistics counter */
418
419void mbinit(void);
420void mbcpuinit(void);
421int nmbclust_update(long);
422struct mbuf *m_copym(struct mbuf *, int, int, int);
423struct mbuf *m_free(struct mbuf *);
424struct mbuf *m_get(int, int);
425struct mbuf *m_getclr(int, int);
426struct mbuf *m_gethdr(int, int);
427struct mbuf *m_inithdr(struct mbuf *);
428void m_removehdr(struct mbuf *);
429void m_resethdr(struct mbuf *);
430void m_calchdrlen(struct mbuf *);
431int m_defrag(struct mbuf *, int);
432struct mbuf *m_prepend(struct mbuf *, int, int);
433struct mbuf *m_pulldown(struct mbuf *, int, int, int *);
434struct mbuf *m_pullup(struct mbuf *, int);
435struct mbuf *m_split(struct mbuf *, int, int);
436struct mbuf *m_makespace(struct mbuf *, int, int, int *);
437struct mbuf *m_getptr(struct mbuf *, int, int *);
438int m_leadingspace(struct mbuf *);
439int m_trailingspace(struct mbuf *);
440void m_align(struct mbuf *, int);
441struct mbuf *m_clget(struct mbuf *, int, u_int);
442void m_extref(struct mbuf *, struct mbuf *);
443void m_pool_init(struct pool *, u_int, u_int, const char *);
444u_int m_pool_used(void);
445void m_extfree_pool(caddr_t, u_int, void *);
446void m_adj(struct mbuf *, int);
447int m_copyback(struct mbuf *, int, int, const void *, int);
448struct mbuf *m_freem(struct mbuf *);
449void m_purge(struct mbuf *);
450void m_copydata(struct mbuf *, int, int, void *);
451void m_cat(struct mbuf *, struct mbuf *);
452struct mbuf *m_devget(char *, int, int);
453int m_apply(struct mbuf *, int, int,
454 int (*)(caddr_t, caddr_t, unsigned int), caddr_t);
455struct mbuf *m_dup_pkt(struct mbuf *, unsigned int, int);
456int m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
457
458void m_microtime(const struct mbuf *, struct timeval *);
459
460static inline struct mbuf *
461m_freemp(struct mbuf **mp)
462{
463 struct mbuf *m = *mp;
464
465 *mp = NULL;
466 return m_freem(m);
467}
468
469#include <sys/percpu.h>
470
471static inline void
472mbstat_inc(enum mbstat_counters c)
473{
474 int s = splnet();
475 counters_inc(mbstat, c);
476 splx(s);
477}
478
479/* Packet tag routines */
480struct m_tag *m_tag_get(int, int, int);
481void m_tag_prepend(struct mbuf *, struct m_tag *);
482void m_tag_delete(struct mbuf *, struct m_tag *);
483void m_tag_delete_chain(struct mbuf *);
484struct m_tag *m_tag_find(struct mbuf *, int, struct m_tag *);
485struct m_tag *m_tag_copy(struct m_tag *, int);
486int m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
487struct m_tag *m_tag_first(struct mbuf *);
488struct m_tag *m_tag_next(struct mbuf *, struct m_tag *);
489
490/* Packet tag types */
491#define PACKET_TAG_IPSEC_IN_DONE 0x0001 /* IPsec applied, in */
492#define PACKET_TAG_IPSEC_OUT_DONE 0x0002 /* IPsec applied, out */
493#define PACKET_TAG_IPSEC_FLOWINFO 0x0004 /* IPsec flowinfo */
494#define PACKET_TAG_IP_OFFNXT 0x0010 /* IPv4 offset and next proto */
495#define PACKET_TAG_IP6_OFFNXT 0x0020 /* IPv6 offset and next proto */
496#define PACKET_TAG_WIREGUARD 0x0040 /* WireGuard data */
497#define PACKET_TAG_GRE 0x0080 /* GRE processing done */
498#define PACKET_TAG_DLT 0x0100 /* data link layer type */
499#define PACKET_TAG_PF_DIVERT 0x0200 /* pf(4) diverted packet */
500#define PACKET_TAG_PF_REASSEMBLED 0x0800 /* pf reassembled ipv6 packet */
501#define PACKET_TAG_SRCROUTE 0x1000 /* IPv4 source routing options */
502#define PACKET_TAG_TUNNEL 0x2000 /* Tunnel endpoint address */
503#define PACKET_TAG_CARP_BAL_IP 0x4000 /* carp(4) ip balanced marker */
504
505#define MTAG_BITS \
506 ("\20\1IPSEC_IN_DONE\2IPSEC_OUT_DONE\3IPSEC_FLOWINFO" \
507 "\4IPSEC_OUT_CRYPTO_NEEDED\5IPSEC_PENDING_TDB\6BRIDGE\7WG\10GRE\11DLT" \
508 "\12PF_DIVERT\14PF_REASSEMBLED\15SRCROUTE\16TUNNEL\17CARP_BAL_IP")
509
510/*
511 * Maximum tag payload length (that is excluding the m_tag structure).
512 * Please make sure to update this value when increasing the payload
513 * length for an existing packet tag type or when adding a new one that
514 * has payload larger than the value below.
515 */
516#define PACKET_TAG_MAXSIZE 80
517
518/* Detect mbufs looping in the kernel when spliced too often. */
519#define M_MAXLOOP 128
520
521/*
522 * mbuf lists
523 */
524
525#define MBUF_LIST_INITIALIZER() { NULL, NULL, 0 }
526
527void ml_init(struct mbuf_list *);
528void ml_enqueue(struct mbuf_list *, struct mbuf *);
529struct mbuf * ml_dequeue(struct mbuf_list *);
530void ml_enlist(struct mbuf_list *, struct mbuf_list *);
531struct mbuf * ml_dechain(struct mbuf_list *);
532unsigned int ml_purge(struct mbuf_list *);
533unsigned int ml_hdatalen(struct mbuf_list *);
534
535#define ml_len(_ml) ((_ml)->ml_len)
536#define ml_empty(_ml) ((_ml)->ml_len == 0)
537
538#define MBUF_LIST_FIRST(_ml) ((_ml)->ml_head)
539#define MBUF_LIST_NEXT(_m) ((_m)->m_nextpkt)
540
541#define MBUF_LIST_FOREACH(_ml, _m) \
542 for ((_m) = MBUF_LIST_FIRST(_ml); \
543 (_m) != NULL; \
544 (_m) = MBUF_LIST_NEXT(_m))
545
546/*
547 * mbuf queues
548 */
549
550#include <sys/atomic.h>
551
552#define MBUF_QUEUE_INITIALIZER(_maxlen, _ipl) \
553 { MUTEX_INITIALIZER(_ipl), MBUF_LIST_INITIALIZER(), (_maxlen), 0 }
554
555void mq_init(struct mbuf_queue *, u_int, int);
556int mq_push(struct mbuf_queue *, struct mbuf *);
557int mq_enqueue(struct mbuf_queue *, struct mbuf *);
558struct mbuf * mq_dequeue(struct mbuf_queue *);
559int mq_enlist(struct mbuf_queue *, struct mbuf_list *);
560void mq_delist(struct mbuf_queue *, struct mbuf_list *);
561unsigned int mq_purge(struct mbuf_queue *);
562unsigned int mq_hdatalen(struct mbuf_queue *);
563void mq_set_maxlen(struct mbuf_queue *, u_int);
564
565#define mq_len(_mq) READ_ONCE((_mq)->mq_list.ml_len)
566#define mq_empty(_mq) (mq_len(_mq) == 0)
567#define mq_full(_mq) (mq_len((_mq)) >= READ_ONCE((_mq)->mq_maxlen))
568#define mq_drops(_mq) READ_ONCE((_mq)->mq_drops)
569
570#endif /* _KERNEL */
571#endif /* _SYS_MBUF_H_ */