mbuf.h revision 52756
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 8.5 (Berkeley) 2/19/95 34 * $FreeBSD: head/sys/sys/mbuf.h 52756 1999-11-01 15:03:20Z phk $ 35 */ 36 37#ifndef _SYS_MBUF_H_ 38#define _SYS_MBUF_H_ 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 *)((intptr_t)(x) & ~(MSIZE-1))) 63#define mtocl(x) (((uintptr_t)(x) - (uintptr_t)mbutl) >> MCLSHIFT) 64#define cltom(x) ((caddr_t)((uintptr_t)mbutl + \ 65 ((uintptr_t)(x) << MCLSHIFT))) 66 67/* header at beginning of each mbuf: */ 68struct m_hdr { 69 struct mbuf *mh_next; /* next buffer in chain */ 70 struct mbuf *mh_nextpkt; /* next chain in queue/record */ 71 caddr_t mh_data; /* location of data */ 72 int mh_len; /* amount of data in this mbuf */ 73 short mh_type; /* type of data in this mbuf */ 74 short mh_flags; /* flags; see below */ 75}; 76 77/* record/packet header in first mbuf of chain; valid if M_PKTHDR set */ 78struct pkthdr { 79 struct ifnet *rcvif; /* rcv interface */ 80 int len; /* total packet length */ 81 82 /* variables for ip and tcp reassembly */ 83 void *header; /* pointer to packet header */ 84}; 85 86/* description of external storage mapped into mbuf, valid if M_EXT set */ 87struct m_ext { 88 caddr_t ext_buf; /* start of buffer */ 89 void (*ext_free) /* free routine if not the usual */ 90 __P((caddr_t, u_int)); 91 u_int ext_size; /* size of buffer, for ext_free */ 92 void (*ext_ref) /* add a reference to the ext object */ 93 __P((caddr_t, u_int)); 94}; 95 96struct mbuf { 97 struct m_hdr m_hdr; 98 union { 99 struct { 100 struct pkthdr MH_pkthdr; /* M_PKTHDR set */ 101 union { 102 struct m_ext MH_ext; /* M_EXT set */ 103 char MH_databuf[MHLEN]; 104 } MH_dat; 105 } MH; 106 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */ 107 } M_dat; 108}; 109#define m_next m_hdr.mh_next 110#define m_len m_hdr.mh_len 111#define m_data m_hdr.mh_data 112#define m_type m_hdr.mh_type 113#define m_flags m_hdr.mh_flags 114#define m_nextpkt m_hdr.mh_nextpkt 115#define m_act m_nextpkt 116#define m_pkthdr M_dat.MH.MH_pkthdr 117#define m_ext M_dat.MH.MH_dat.MH_ext 118#define m_pktdat M_dat.MH.MH_dat.MH_databuf 119#define m_dat M_dat.M_databuf 120 121/* mbuf flags */ 122#define M_EXT 0x0001 /* has associated external storage */ 123#define M_PKTHDR 0x0002 /* start of record */ 124#define M_EOR 0x0004 /* end of record */ 125#define M_PROTO1 0x0008 /* protocol-specific */ 126 127/* mbuf pkthdr flags, also in m_flags */ 128#define M_BCAST 0x0100 /* send/received as link-level broadcast */ 129#define M_MCAST 0x0200 /* send/received as link-level multicast */ 130#define M_FRAG 0x0400 /* packet is a fragment of a larger packet */ 131 132/* flags copied when copying m_pkthdr */ 133#define M_COPYFLAGS (M_PKTHDR|M_EOR|M_PROTO1|M_BCAST|M_MCAST) 134 135/* mbuf types */ 136#define MT_FREE 0 /* should be on free list */ 137#define MT_DATA 1 /* dynamic (data) allocation */ 138#define MT_HEADER 2 /* packet header */ 139/*efine MT_SOCKET 3*/ /* socket structure */ 140/*efine MT_PCB 4*/ /* protocol control block */ 141/*efine MT_RTABLE 5*/ /* routing tables */ 142/*efine MT_HTABLE 6*/ /* IMP host tables */ 143/*efine MT_ATABLE 7*/ /* address resolution tables */ 144#define MT_SONAME 8 /* socket name */ 145/*efine MT_SOOPTS 10*/ /* socket options */ 146#define MT_FTABLE 11 /* fragment reassembly header */ 147/*efine MT_RIGHTS 12*/ /* access rights */ 148/*efine MT_IFADDR 13*/ /* interface address */ 149#define MT_CONTROL 14 /* extra-data protocol message */ 150#define MT_OOBDATA 15 /* expedited data */ 151 152/* flags to m_get/MGET */ 153#define M_DONTWAIT 1 154#define M_WAIT 0 155 156/* Freelists: 157 * 158 * Normal mbuf clusters are normally treated as character arrays 159 * after allocation, but use the first word of the buffer as a free list 160 * pointer while on the free list. 161 */ 162union mcluster { 163 union mcluster *mcl_next; 164 char mcl_buf[MCLBYTES]; 165}; 166 167/* 168 * mbuf utility macros: 169 * 170 * MBUFLOCK(code) 171 * prevents a section of code from from being interrupted by network 172 * drivers. 173 */ 174#define MBUFLOCK(code) \ 175 do { int ms = splimp(); \ 176 { code } \ 177 splx(ms); \ 178 } while(0) 179 180/* 181 * mbuf allocation/deallocation macros: 182 * 183 * MGET(struct mbuf *m, int how, int type) 184 * allocates an mbuf and initializes it to contain internal data. 185 * 186 * MGETHDR(struct mbuf *m, int how, int type) 187 * allocates an mbuf and initializes it to contain a packet header 188 * and internal data. 189 */ 190#define MGET(m, how, type) { \ 191 int _ms = splimp(); \ 192 if (mmbfree == 0) \ 193 (void)m_mballoc(1, (how)); \ 194 if (((m) = mmbfree) != 0) { \ 195 mmbfree = (m)->m_next; \ 196 mbstat.m_mtypes[MT_FREE]--; \ 197 (m)->m_type = (type); \ 198 mbstat.m_mtypes[type]++; \ 199 (m)->m_next = (struct mbuf *)NULL; \ 200 (m)->m_nextpkt = (struct mbuf *)NULL; \ 201 (m)->m_data = (m)->m_dat; \ 202 (m)->m_flags = 0; \ 203 splx(_ms); \ 204 } else { \ 205 splx(_ms); \ 206 (m) = m_retry((how), (type)); \ 207 } \ 208} 209 210#define MGETHDR(m, how, type) { \ 211 int _ms = splimp(); \ 212 if (mmbfree == 0) \ 213 (void)m_mballoc(1, (how)); \ 214 if (((m) = mmbfree) != 0) { \ 215 mmbfree = (m)->m_next; \ 216 mbstat.m_mtypes[MT_FREE]--; \ 217 (m)->m_type = (type); \ 218 mbstat.m_mtypes[type]++; \ 219 (m)->m_next = (struct mbuf *)NULL; \ 220 (m)->m_nextpkt = (struct mbuf *)NULL; \ 221 (m)->m_data = (m)->m_pktdat; \ 222 (m)->m_flags = M_PKTHDR; \ 223 splx(_ms); \ 224 } else { \ 225 splx(_ms); \ 226 (m) = m_retryhdr((how), (type)); \ 227 } \ 228} 229 230/* 231 * Mbuf cluster macros. 232 * MCLALLOC(caddr_t p, int how) allocates an mbuf cluster. 233 * MCLGET adds such clusters to a normal mbuf; 234 * the flag M_EXT is set upon success. 235 * MCLFREE releases a reference to a cluster allocated by MCLALLOC, 236 * freeing the cluster if the reference count has reached 0. 237 */ 238#define MCLALLOC(p, how) \ 239 MBUFLOCK( \ 240 if (mclfree == 0) \ 241 (void)m_clalloc(1, (how)); \ 242 if (((p) = (caddr_t)mclfree) != 0) { \ 243 ++mclrefcnt[mtocl(p)]; \ 244 mbstat.m_clfree--; \ 245 mclfree = ((union mcluster *)(p))->mcl_next; \ 246 } \ 247 ) 248 249#define MCLGET(m, how) \ 250 { MCLALLOC((m)->m_ext.ext_buf, (how)); \ 251 if ((m)->m_ext.ext_buf != NULL) { \ 252 (m)->m_data = (m)->m_ext.ext_buf; \ 253 (m)->m_flags |= M_EXT; \ 254 (m)->m_ext.ext_free = NULL; \ 255 (m)->m_ext.ext_ref = NULL; \ 256 (m)->m_ext.ext_size = MCLBYTES; \ 257 } \ 258 } 259 260#define MCLFREE1(p) \ 261 do { \ 262 if (--mclrefcnt[mtocl(p)] == 0) { \ 263 ((union mcluster *)(p))->mcl_next = mclfree; \ 264 mclfree = (union mcluster *)(p); \ 265 mbstat.m_clfree++; \ 266 } \ 267 } while (0) 268 269#define MCLFREE(p) \ 270 MBUFLOCK( \ 271 MCLFREE1(p); \ 272 ) 273 274#define MEXTFREE1(m) \ 275 do { \ 276 if ((m)->m_ext.ext_free) \ 277 (*((m)->m_ext.ext_free))((m)->m_ext.ext_buf, \ 278 (m)->m_ext.ext_size); \ 279 else { \ 280 char *p = (m)->m_ext.ext_buf; \ 281 MCLFREE1(p); \ 282 } \ 283 } while (0) 284 285#define MEXTFREE(m) \ 286 MBUFLOCK( \ 287 MCLEXTFREE1(m); \ 288 ) 289 290/* 291 * MFREE(struct mbuf *m, struct mbuf *n) 292 * Free a single mbuf and associated external storage. 293 * Place the successor, if any, in n. 294 */ 295#define MFREE(m, n) \ 296 MBUFLOCK( \ 297 mbstat.m_mtypes[(m)->m_type]--; \ 298 if ((m)->m_flags & M_EXT) { \ 299 MEXTFREE1(m); \ 300 } \ 301 (n) = (m)->m_next; \ 302 (m)->m_type = MT_FREE; \ 303 mbstat.m_mtypes[MT_FREE]++; \ 304 (m)->m_next = mmbfree; \ 305 mmbfree = (m); \ 306 ) 307 308/* 309 * Copy mbuf pkthdr from from to to. 310 * from must have M_PKTHDR set, and to must be empty. 311 */ 312#define M_COPY_PKTHDR(to, from) { \ 313 (to)->m_pkthdr = (from)->m_pkthdr; \ 314 (to)->m_flags = (from)->m_flags & M_COPYFLAGS; \ 315 (to)->m_data = (to)->m_pktdat; \ 316} 317 318/* 319 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place 320 * an object of the specified size at the end of the mbuf, longword aligned. 321 */ 322#define M_ALIGN(m, len) \ 323 { (m)->m_data += (MLEN - (len)) &~ (sizeof(long) - 1); } 324/* 325 * As above, for mbufs allocated with m_gethdr/MGETHDR 326 * or initialized by M_COPY_PKTHDR. 327 */ 328#define MH_ALIGN(m, len) \ 329 { (m)->m_data += (MHLEN - (len)) &~ (sizeof(long) - 1); } 330 331/* 332 * Compute the amount of space available 333 * before the current start of data in an mbuf. 334 */ 335#define M_LEADINGSPACE(m) \ 336 ((m)->m_flags & M_EXT ? /* (m)->m_data - (m)->m_ext.ext_buf */ 0 : \ 337 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \ 338 (m)->m_data - (m)->m_dat) 339 340/* 341 * Compute the amount of space available 342 * after the end of data in an mbuf. 343 */ 344#define M_TRAILINGSPACE(m) \ 345 ((m)->m_flags & M_EXT ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size - \ 346 ((m)->m_data + (m)->m_len) : \ 347 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len)) 348 349/* 350 * Arrange to prepend space of size plen to mbuf m. 351 * If a new mbuf must be allocated, how specifies whether to wait. 352 * If how is M_DONTWAIT and allocation fails, the original mbuf chain 353 * is freed and m is set to NULL. 354 */ 355#define M_PREPEND(m, plen, how) { \ 356 if (M_LEADINGSPACE(m) >= (plen)) { \ 357 (m)->m_data -= (plen); \ 358 (m)->m_len += (plen); \ 359 } else \ 360 (m) = m_prepend((m), (plen), (how)); \ 361 if ((m) && (m)->m_flags & M_PKTHDR) \ 362 (m)->m_pkthdr.len += (plen); \ 363} 364 365/* change mbuf to new type */ 366#define MCHTYPE(m, t) do { \ 367 MBUFLOCK(mbstat.m_mtypes[(m)->m_type]--; mbstat.m_mtypes[t]++;); \ 368 (m)->m_type = t;\ 369} while(0) 370 371/* length to m_copy to copy all */ 372#define M_COPYALL 1000000000 373 374/* compatibility with 4.3 */ 375#define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT) 376 377/* 378 * Mbuf statistics. 379 */ 380struct mbstat { 381 u_long m_mbufs; /* mbufs obtained from page pool */ 382 u_long m_clusters; /* clusters obtained from page pool */ 383 u_long m_spare; /* spare field */ 384 u_long m_clfree; /* free clusters */ 385 u_long m_drops; /* times failed to find space */ 386 u_long m_wait; /* times waited for space */ 387 u_long m_drain; /* times drained protocols for space */ 388 u_short m_mtypes[256]; /* type specific mbuf allocations */ 389 u_long m_mcfail; /* times m_copym failed */ 390 u_long m_mpfail; /* times m_pullup failed */ 391 u_long m_msize; /* length of an mbuf */ 392 u_long m_mclbytes; /* length of an mbuf cluster */ 393 u_long m_minclsize; /* min length of data to allocate a cluster */ 394 u_long m_mlen; /* length of data in an mbuf */ 395 u_long m_mhlen; /* length of data in a header mbuf */ 396}; 397 398#ifdef KERNEL 399extern struct mbuf *mbutl; /* virtual address of mclusters */ 400extern char *mclrefcnt; /* cluster reference counts */ 401extern struct mbstat mbstat; 402extern int nmbclusters; 403extern int nmbufs; 404extern int nsfbufs; 405extern struct mbuf *mmbfree; 406extern union mcluster *mclfree; 407extern int max_linkhdr; /* largest link-level header */ 408extern int max_protohdr; /* largest protocol header */ 409extern int max_hdr; /* largest link+protocol header */ 410extern int max_datalen; /* MHLEN - max_hdr */ 411 412struct mbuf *m_copym __P((struct mbuf *, int, int, int)); 413struct mbuf *m_copypacket __P((struct mbuf *, int)); 414struct mbuf *m_devget __P((char *, int, int, struct ifnet *, 415 void (*copy)(char *, caddr_t, u_int))); 416struct mbuf *m_free __P((struct mbuf *)); 417struct mbuf *m_get __P((int, int)); 418struct mbuf *m_getclr __P((int, int)); 419struct mbuf *m_gethdr __P((int, int)); 420struct mbuf *m_prepend __P((struct mbuf *,int,int)); 421void m_print __P((const struct mbuf *m)); 422struct mbuf *m_pullup __P((struct mbuf *, int)); 423struct mbuf *m_retry __P((int, int)); 424struct mbuf *m_retryhdr __P((int, int)); 425struct mbuf *m_split __P((struct mbuf *,int,int)); 426void m_adj __P((struct mbuf *, int)); 427void m_cat __P((struct mbuf *,struct mbuf *)); 428int m_mballoc __P((int, int)); 429int m_clalloc __P((int, int)); 430void m_copyback __P((struct mbuf *, int, int, caddr_t)); 431void m_copydata __P((struct mbuf *,int,int,caddr_t)); 432void m_freem __P((struct mbuf *)); 433#endif /* KERNEL */ 434 435#endif /* !_SYS_MBUF_H_ */ 436