1 /*
2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)mbuf.h 8.3 (Berkeley) 1/21/94
34 */
35
36 #ifndef M_WAITOK
37 #include <sys/malloc.h>
38 #endif
39
40 /*
41 * Mbufs are of a single size, MSIZE (machine/machparam.h), which
42 * includes overhead. An mbuf may add a single "mbuf cluster" of size
43 * MCLBYTES (also in machine/machparam.h), which has no additional overhead
44 * and is used instead of the internal data area; this is done when
45 * at least MINCLSIZE of data must be stored.
46 */
47
48 #define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */
49 #define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */
50
51 #define MINCLSIZE (MHLEN + MLEN) /* smallest amount to put in cluster */
52 #define M_MAXCOMPRESS (MHLEN / 2) /* max amount to copy for compression */
53
54 /*
55 * Macros for type conversion
56 * mtod(m,t) - convert mbuf pointer to data pointer of correct type
57 * dtom(x) - convert data pointer within mbuf to mbuf pointer (XXX)
58 * mtocl(x) - convert pointer within cluster to cluster index #
59 * cltom(x) - convert cluster # to ptr to beginning of cluster
60 */
61 #define mtod(m,t) ((t)((m)->m_data))
62 #define dtom(x) ((struct mbuf *)((int)(x) & ~(MSIZE-1)))
63 #define mtocl(x) (((u_int)(x) - (u_int)mbutl) >> MCLSHIFT)
64 #define cltom(x) ((caddr_t)((u_int)mbutl + ((u_int)(x) << MCLSHIFT)))
65
66 /* header at beginning of each mbuf: */
67 struct m_hdr {
68 struct mbuf *mh_next; /* next buffer in chain */
69 struct mbuf *mh_nextpkt; /* next chain in queue/record */
70 int mh_len; /* amount of data in this mbuf */
71 caddr_t mh_data; /* location of data */
72 short mh_type; /* type of data in this mbuf */
73 short mh_flags; /* flags; see below */
74 };
75
76 /* record/packet header in first mbuf of chain; valid if M_PKTHDR set */
77 struct pkthdr {
78 int len; /* total packet length */
79 struct ifnet *rcvif; /* rcv interface */
80 };
81
82 /* description of external storage mapped into mbuf, valid if M_EXT set */
83 struct m_ext {
84 caddr_t ext_buf; /* start of buffer */
85 void (*ext_free)(); /* free routine if not the usual */
86 u_int ext_size; /* size of buffer, for ext_free */
87 };
88
89 struct mbuf {
90 struct m_hdr m_hdr;
91 union {
92 struct {
93 struct pkthdr MH_pkthdr; /* M_PKTHDR set */
94 union {
95 struct m_ext MH_ext; /* M_EXT set */
96 char MH_databuf[MHLEN];
97 } MH_dat;
98 } MH;
99 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */
100 } M_dat;
101 };
102 #define m_next m_hdr.mh_next
103 #define m_len m_hdr.mh_len
104 #define m_data m_hdr.mh_data
105 #define m_type m_hdr.mh_type
106 #define m_flags m_hdr.mh_flags
107 #define m_nextpkt m_hdr.mh_nextpkt
108 #define m_act m_nextpkt
109 #define m_pkthdr M_dat.MH.MH_pkthdr
110 #define m_ext M_dat.MH.MH_dat.MH_ext
111 #define m_pktdat M_dat.MH.MH_dat.MH_databuf
112 #define m_dat M_dat.M_databuf
113
114 /* mbuf flags */
115 #define M_EXT 0x0001 /* has associated external storage */
116 #define M_PKTHDR 0x0002 /* start of record */
117 #define M_EOR 0x0004 /* end of record */
118
119 /* mbuf pkthdr flags, also in m_flags */
120 #define M_BCAST 0x0100 /* send/received as link-level broadcast */
121 #define M_MCAST 0x0200 /* send/received as link-level multicast */
122
123 /* flags copied when copying m_pkthdr */
124 #define M_COPYFLAGS (M_PKTHDR|M_EOR|M_BCAST|M_MCAST)
125
126 /* mbuf types */
127 #define MT_FREE 0 /* should be on free list */
128 #define MT_DATA 1 /* dynamic (data) allocation */
129 #define MT_HEADER 2 /* packet header */
130 #define MT_SOCKET 3 /* socket structure */
131 #define MT_PCB 4 /* protocol control block */
132 #define MT_RTABLE 5 /* routing tables */
133 #define MT_HTABLE 6 /* IMP host tables */
134 #define MT_ATABLE 7 /* address resolution tables */
135 #define MT_SONAME 8 /* socket name */
136 #define MT_SOOPTS 10 /* socket options */
137 #define MT_FTABLE 11 /* fragment reassembly header */
138 #define MT_RIGHTS 12 /* access rights */
139 #define MT_IFADDR 13 /* interface address */
140 #define MT_CONTROL 14 /* extra-data protocol message */
141 #define MT_OOBDATA 15 /* expedited data */
142
143 /* flags to m_get/MGET */
144 #define M_DONTWAIT M_NOWAIT
145 #define M_WAIT M_WAITOK
146
147 /*
148 * mbuf utility macros:
149 *
150 * MBUFLOCK(code)
151 * prevents a section of code from from being interrupted by network
152 * drivers.
153 */
154 #define MBUFLOCK(code) \
155 { int ms = splimp(); \
156 { code } \
157 splx(ms); \
158 }
159
160 /*
161 * mbuf allocation/deallocation macros:
162 *
163 * MGET(struct mbuf *m, int how, int type)
164 * allocates an mbuf and initializes it to contain internal data.
165 *
166 * MGETHDR(struct mbuf *m, int how, int type)
167 * allocates an mbuf and initializes it to contain a packet header
168 * and internal data.
169 */
170 #define MGET(m, how, type) { \
171 MALLOC((m), struct mbuf *, MSIZE, mbtypes[type], (how)); \
172 if (m) { \
173 (m)->m_type = (type); \
174 MBUFLOCK(mbstat.m_mtypes[type]++;) \
175 (m)->m_next = (struct mbuf *)NULL; \
176 (m)->m_nextpkt = (struct mbuf *)NULL; \
177 (m)->m_data = (m)->m_dat; \
178 (m)->m_flags = 0; \
179 } else \
180 (m) = m_retry((how), (type)); \
181 }
182
183 #define MGETHDR(m, how, type) { \
184 MALLOC((m), struct mbuf *, MSIZE, mbtypes[type], (how)); \
185 if (m) { \
186 (m)->m_type = (type); \
187 MBUFLOCK(mbstat.m_mtypes[type]++;) \
188 (m)->m_next = (struct mbuf *)NULL; \
189 (m)->m_nextpkt = (struct mbuf *)NULL; \
190 (m)->m_data = (m)->m_pktdat; \
191 (m)->m_flags = M_PKTHDR; \
192 } else \
193 (m) = m_retryhdr((how), (type)); \
194 }
195
196 /*
197 * Mbuf cluster macros.
198 * MCLALLOC(caddr_t p, int how) allocates an mbuf cluster.
199 * MCLGET adds such clusters to a normal mbuf;
200 * the flag M_EXT is set upon success.
201 * MCLFREE releases a reference to a cluster allocated by MCLALLOC,
202 * freeing the cluster if the reference count has reached 0.
203 *
204 * Normal mbuf clusters are normally treated as character arrays
205 * after allocation, but use the first word of the buffer as a free list
206 * pointer while on the free list.
207 */
208 union mcluster {
209 union mcluster *mcl_next;
210 char mcl_buf[MCLBYTES];
211 };
212
213 #define MCLALLOC(p, how) \
214 MBUFLOCK( \
215 if (mclfree == 0) \
216 (void)m_clalloc(1, (how)); \
217 if ((p) = (caddr_t)mclfree) { \
218 ++mclrefcnt[mtocl(p)]; \
219 mbstat.m_clfree--; \
220 mclfree = ((union mcluster *)(p))->mcl_next; \
221 } \
222 )
223
224 #define MCLGET(m, how) \
225 { MCLALLOC((m)->m_ext.ext_buf, (how)); \
226 if ((m)->m_ext.ext_buf != NULL) { \
227 (m)->m_data = (m)->m_ext.ext_buf; \
228 (m)->m_flags |= M_EXT; \
229 (m)->m_ext.ext_size = MCLBYTES; \
230 } \
231 }
232
233 #define MCLFREE(p) \
234 MBUFLOCK ( \
235 if (--mclrefcnt[mtocl(p)] == 0) { \
236 ((union mcluster *)(p))->mcl_next = mclfree; \
237 mclfree = (union mcluster *)(p); \
238 mbstat.m_clfree++; \
239 } \
240 )
241
242 /*
243 * MFREE(struct mbuf *m, struct mbuf *n)
244 * Free a single mbuf and associated external storage.
245 * Place the successor, if any, in n.
246 */
247 #ifdef notyet
248 #define MFREE(m, n) \
249 { MBUFLOCK(mbstat.m_mtypes[(m)->m_type]--;) \
250 if ((m)->m_flags & M_EXT) { \
251 if ((m)->m_ext.ext_free) \
252 (*((m)->m_ext.ext_free))((m)->m_ext.ext_buf, \
253 (m)->m_ext.ext_size); \
254 else \
255 MCLFREE((m)->m_ext.ext_buf); \
256 } \
257 (n) = (m)->m_next; \
258 FREE((m), mbtypes[(m)->m_type]); \
259 }
260 #else /* notyet */
261 #define MFREE(m, nn) \
262 { MBUFLOCK(mbstat.m_mtypes[(m)->m_type]--;) \
263 if ((m)->m_flags & M_EXT) { \
264 MCLFREE((m)->m_ext.ext_buf); \
265 } \
266 (nn) = (m)->m_next; \
267 FREE((m), mbtypes[(m)->m_type]); \
268 }
269 #endif
270
271 /*
272 * Copy mbuf pkthdr from from to to.
273 * from must have M_PKTHDR set, and to must be empty.
274 */
275 #define M_COPY_PKTHDR(to, from) { \
276 (to)->m_pkthdr = (from)->m_pkthdr; \
277 (to)->m_flags = (from)->m_flags & M_COPYFLAGS; \
278 (to)->m_data = (to)->m_pktdat; \
279 }
280
281 /*
282 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
283 * an object of the specified size at the end of the mbuf, longword aligned.
284 */
285 #define M_ALIGN(m, len) \
286 { (m)->m_data += (MLEN - (len)) &~ (sizeof(long) - 1); }
287 /*
288 * As above, for mbufs allocated with m_gethdr/MGETHDR
289 * or initialized by M_COPY_PKTHDR.
290 */
291 #define MH_ALIGN(m, len) \
292 { (m)->m_data += (MHLEN - (len)) &~ (sizeof(long) - 1); }
293
294 /*
295 * Compute the amount of space available
296 * before the current start of data in an mbuf.
297 */
298 #define M_LEADINGSPACE(m) \
299 ((m)->m_flags & M_EXT ? /* (m)->m_data - (m)->m_ext.ext_buf */ 0 : \
300 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \
301 (m)->m_data - (m)->m_dat)
302
303 /*
304 * Compute the amount of space available
305 * after the end of data in an mbuf.
306 */
307 #define M_TRAILINGSPACE(m) \
308 ((m)->m_flags & M_EXT ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size - \
309 ((m)->m_data + (m)->m_len) : \
310 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
311
312 /*
313 * Arrange to prepend space of size plen to mbuf m.
314 * If a new mbuf must be allocated, how specifies whether to wait.
315 * If how is M_DONTWAIT and allocation fails, the original mbuf chain
316 * is freed and m is set to NULL.
317 */
318 #define M_PREPEND(m, plen, how) { \
319 if (M_LEADINGSPACE(m) >= (plen)) { \
320 (m)->m_data -= (plen); \
321 (m)->m_len += (plen); \
322 } else \
323 (m) = m_prepend((m), (plen), (how)); \
324 if ((m) && (m)->m_flags & M_PKTHDR) \
325 (m)->m_pkthdr.len += (plen); \
326 }
327
328 /* change mbuf to new type */
329 #define MCHTYPE(m, t) { \
330 MBUFLOCK(mbstat.m_mtypes[(m)->m_type]--; mbstat.m_mtypes[t]++;) \
331 (m)->m_type = t;\
332 }
333
334 /* length to m_copy to copy all */
335 #define M_COPYALL 1000000000
336
337 /* compatiblity with 4.3 */
338 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT)
339
340 /*
341 * Mbuf statistics.
342 */
343 struct mbstat {
344 u_long m_mbufs; /* mbufs obtained from page pool */ //从页池中获得的mbuf数
345 u_long m_clusters; /* clusters obtained from page pool */
346 u_long m_spare; /* spare field */
347 u_long m_clfree; /* free clusters */
348 u_long m_drops; /* times failed to find space */
349 u_long m_wait; /* times waited for space */
350 u_long m_drain; /* times drained protocols for space */
351 u_short m_mtypes[256]; /* type specific mbuf allocations */
352 };
353
354 #ifdef KERNEL
355 extern struct mbuf *mbutl; /* virtual address of mclusters */
356 extern char *mclrefcnt; /* cluster reference counts */
357 struct mbstat mbstat;
358 extern int nmbclusters;
359 union mcluster *mclfree;
360 int max_linkhdr; /* largest link-level header */
361 int max_protohdr; /* largest protocol header */
362 int max_hdr; /* largest link+protocol header */
363 int max_datalen; /* MHLEN - max_hdr */
364 extern int mbtypes[]; /* XXX */
365
366 struct mbuf *m_copym __P((struct mbuf *, int, int, int));
367 struct mbuf *m_free __P((struct mbuf *));
368 struct mbuf *m_get __P((int, int));
369 struct mbuf *m_getclr __P((int, int));
370 struct mbuf *m_gethdr __P((int, int));
371 struct mbuf *m_prepend __P((struct mbuf *, int, int));
372 struct mbuf *m_pullup __P((struct mbuf *, int));
373 struct mbuf *m_retry __P((int, int));
374 struct mbuf *m_retryhdr __P((int, int));
375 int m_clalloc __P((int, int));
376 void m_copyback __P((struct mbuf *, int, int, caddr_t));
377 void m_freem __P((struct mbuf *));
378
379 #ifdef MBTYPES
380 int mbtypes[] = { /* XXX */
381 M_FREE, /* MT_FREE 0 should be on free list */
382 M_MBUF, /* MT_DATA 1 dynamic (data) allocation */
383 M_MBUF, /* MT_HEADER 2 packet header */
384 M_SOCKET, /* MT_SOCKET 3 socket structure */
385 M_PCB, /* MT_PCB 4 protocol control block */
386 M_RTABLE, /* MT_RTABLE 5 routing tables */
387 M_HTABLE, /* MT_HTABLE 6 IMP host tables */
388 0, /* MT_ATABLE 7 address resolution tables */
389 M_MBUF, /* MT_SONAME 8 socket name */
390 0, /* 9 */
391 M_SOOPTS, /* MT_SOOPTS 10 socket options */
392 M_FTABLE, /* MT_FTABLE 11 fragment reassembly header */
393 M_MBUF, /* MT_RIGHTS 12 access rights */
394 M_IFADDR, /* MT_IFADDR 13 interface address */
395 M_MBUF, /* MT_CONTROL 14 extra-data protocol message */
396 M_MBUF, /* MT_OOBDATA 15 expedited data */
397 #ifdef DATAKIT
398 25, 26, 27, 28, 29, 30, 31, 32 /* datakit ugliness */
399 #endif
400 };
401 #endif
402 #endif
403
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