mbuf.h revision 37653
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 * $Id: mbuf.h,v 1.26 1997/12/28 01:04:47 bde Exp $ 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 83/* description of external storage mapped into mbuf, valid if M_EXT set */ 84struct m_ext { 85 caddr_t ext_buf; /* start of buffer */ 86 void (*ext_free) /* free routine if not the usual */ 87 __P((caddr_t, u_int)); 88 u_int ext_size; /* size of buffer, for ext_free */ 89 void (*ext_ref) /* add a reference to the ext object */ 90 __P((caddr_t, u_int)); 91}; 92 93struct mbuf { 94 struct m_hdr m_hdr; 95 union { 96 struct { 97 struct pkthdr MH_pkthdr; /* M_PKTHDR set */ 98 union { 99 struct m_ext MH_ext; /* M_EXT set */ 100 char MH_databuf[MHLEN]; 101 } MH_dat; 102 } MH; 103 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */ 104 } M_dat; 105}; 106#define m_next m_hdr.mh_next 107#define m_len m_hdr.mh_len 108#define m_data m_hdr.mh_data 109#define m_type m_hdr.mh_type 110#define m_flags m_hdr.mh_flags 111#define m_nextpkt m_hdr.mh_nextpkt 112#define m_act m_nextpkt 113#define m_pkthdr M_dat.MH.MH_pkthdr 114#define m_ext M_dat.MH.MH_dat.MH_ext 115#define m_pktdat M_dat.MH.MH_dat.MH_databuf 116#define m_dat M_dat.M_databuf 117 118/* mbuf flags */ 119#define M_EXT 0x0001 /* has associated external storage */ 120#define M_PKTHDR 0x0002 /* start of record */ 121#define M_EOR 0x0004 /* end of record */ 122#define M_PROTO1 0x0008 /* protocol-specific */ 123 124/* mbuf pkthdr flags, also in m_flags */ 125#define M_BCAST 0x0100 /* send/received as link-level broadcast */ 126#define M_MCAST 0x0200 /* send/received as link-level multicast */ 127 128/* flags copied when copying m_pkthdr */ 129#define M_COPYFLAGS (M_PKTHDR|M_EOR|M_PROTO1|M_BCAST|M_MCAST) 130 131/* mbuf types */ 132#define MT_FREE 0 /* should be on free list */ 133#define MT_DATA 1 /* dynamic (data) allocation */ 134#define MT_HEADER 2 /* packet header */ 135/*efine MT_SOCKET 3*/ /* socket structure */ 136/*efine MT_PCB 4*/ /* protocol control block */ 137#define MT_RTABLE 5 /* routing tables */ 138/*efine MT_HTABLE 6*/ /* IMP host tables */ 139/*efine MT_ATABLE 7*/ /* address resolution tables */ 140#define MT_SONAME 8 /* socket name */ 141#define MT_SOOPTS 10 /* socket options */ 142#define MT_FTABLE 11 /* fragment reassembly header */ 143/*efine MT_RIGHTS 12*/ /* access rights */ 144/*efine MT_IFADDR 13*/ /* interface address */ 145#define MT_CONTROL 14 /* extra-data protocol message */ 146#define MT_OOBDATA 15 /* expedited data */ 147 148/* flags to m_get/MGET */ 149#define M_DONTWAIT 1 150#define M_WAIT 0 151 152/* Freelists: 153 * 154 * Normal mbuf clusters are normally treated as character arrays 155 * after allocation, but use the first word of the buffer as a free list 156 * pointer while on the free list. 157 */ 158union mcluster { 159 union mcluster *mcl_next; 160 char mcl_buf[MCLBYTES]; 161}; 162 163/* 164 * mbuf utility macros: 165 * 166 * MBUFLOCK(code) 167 * prevents a section of code from from being interrupted by network 168 * drivers. 169 */ 170#define MBUFLOCK(code) \ 171 { int ms = splimp(); \ 172 { code } \ 173 splx(ms); \ 174 } 175 176/* 177 * mbuf allocation/deallocation macros: 178 * 179 * MGET(struct mbuf *m, int how, int type) 180 * allocates an mbuf and initializes it to contain internal data. 181 * 182 * MGETHDR(struct mbuf *m, int how, int type) 183 * allocates an mbuf and initializes it to contain a packet header 184 * and internal data. 185 */ 186#define MGET(m, how, type) { \ 187 int _ms = splimp(); \ 188 if (mmbfree == 0) \ 189 (void)m_mballoc(1, (how)); \ 190 if (((m) = mmbfree) != 0) { \ 191 mmbfree = (m)->m_next; \ 192 mbstat.m_mtypes[MT_FREE]--; \ 193 (m)->m_type = (type); \ 194 mbstat.m_mtypes[type]++; \ 195 (m)->m_next = (struct mbuf *)NULL; \ 196 (m)->m_nextpkt = (struct mbuf *)NULL; \ 197 (m)->m_data = (m)->m_dat; \ 198 (m)->m_flags = 0; \ 199 splx(_ms); \ 200 } else { \ 201 splx(_ms); \ 202 (m) = m_retry((how), (type)); \ 203 } \ 204} 205 206#define MGETHDR(m, how, type) { \ 207 int _ms = splimp(); \ 208 if (mmbfree == 0) \ 209 (void)m_mballoc(1, (how)); \ 210 if (((m) = mmbfree) != 0) { \ 211 mmbfree = (m)->m_next; \ 212 mbstat.m_mtypes[MT_FREE]--; \ 213 (m)->m_type = (type); \ 214 mbstat.m_mtypes[type]++; \ 215 (m)->m_next = (struct mbuf *)NULL; \ 216 (m)->m_nextpkt = (struct mbuf *)NULL; \ 217 (m)->m_data = (m)->m_pktdat; \ 218 (m)->m_flags = M_PKTHDR; \ 219 splx(_ms); \ 220 } else { \ 221 splx(_ms); \ 222 (m) = m_retryhdr((how), (type)); \ 223 } \ 224} 225 226/* 227 * Mbuf cluster macros. 228 * MCLALLOC(caddr_t p, int how) allocates an mbuf cluster. 229 * MCLGET adds such clusters to a normal mbuf; 230 * the flag M_EXT is set upon success. 231 * MCLFREE releases a reference to a cluster allocated by MCLALLOC, 232 * freeing the cluster if the reference count has reached 0. 233 */ 234#define MCLALLOC(p, how) \ 235 MBUFLOCK( \ 236 if (mclfree == 0) \ 237 (void)m_clalloc(1, (how)); \ 238 if (((p) = (caddr_t)mclfree) != 0) { \ 239 ++mclrefcnt[mtocl(p)]; \ 240 mbstat.m_clfree--; \ 241 mclfree = ((union mcluster *)(p))->mcl_next; \ 242 } \ 243 ) 244 245#define MCLGET(m, how) \ 246 { MCLALLOC((m)->m_ext.ext_buf, (how)); \ 247 if ((m)->m_ext.ext_buf != NULL) { \ 248 (m)->m_data = (m)->m_ext.ext_buf; \ 249 (m)->m_flags |= M_EXT; \ 250 (m)->m_ext.ext_free = NULL; \ 251 (m)->m_ext.ext_ref = NULL; \ 252 (m)->m_ext.ext_size = MCLBYTES; \ 253 } \ 254 } 255 256#define MCLFREE(p) \ 257 MBUFLOCK ( \ 258 if (--mclrefcnt[mtocl(p)] == 0) { \ 259 ((union mcluster *)(p))->mcl_next = mclfree; \ 260 mclfree = (union mcluster *)(p); \ 261 mbstat.m_clfree++; \ 262 } \ 263 ) 264 265/* 266 * MFREE(struct mbuf *m, struct mbuf *n) 267 * Free a single mbuf and associated external storage. 268 * Place the successor, if any, in n. 269 */ 270#define MFREE(m, n) \ 271 MBUFLOCK( \ 272 mbstat.m_mtypes[(m)->m_type]--; \ 273 if ((m)->m_flags & M_EXT) { \ 274 if ((m)->m_ext.ext_free) \ 275 (*((m)->m_ext.ext_free))((m)->m_ext.ext_buf, \ 276 (m)->m_ext.ext_size); \ 277 else { \ 278 char *p = (m)->m_ext.ext_buf; \ 279 if (--mclrefcnt[mtocl(p)] == 0) { \ 280 ((union mcluster *)(p))->mcl_next = mclfree; \ 281 mclfree = (union mcluster *)(p); \ 282 mbstat.m_clfree++; \ 283 } \ 284 } \ 285 } \ 286 (n) = (m)->m_next; \ 287 (m)->m_type = MT_FREE; \ 288 mbstat.m_mtypes[MT_FREE]++; \ 289 (m)->m_next = mmbfree; \ 290 mmbfree = (m); \ 291 ) 292 293/* 294 * Copy mbuf pkthdr from from to to. 295 * from must have M_PKTHDR set, and to must be empty. 296 */ 297#define M_COPY_PKTHDR(to, from) { \ 298 (to)->m_pkthdr = (from)->m_pkthdr; \ 299 (to)->m_flags = (from)->m_flags & M_COPYFLAGS; \ 300 (to)->m_data = (to)->m_pktdat; \ 301} 302 303/* 304 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place 305 * an object of the specified size at the end of the mbuf, longword aligned. 306 */ 307#define M_ALIGN(m, len) \ 308 { (m)->m_data += (MLEN - (len)) &~ (sizeof(long) - 1); } 309/* 310 * As above, for mbufs allocated with m_gethdr/MGETHDR 311 * or initialized by M_COPY_PKTHDR. 312 */ 313#define MH_ALIGN(m, len) \ 314 { (m)->m_data += (MHLEN - (len)) &~ (sizeof(long) - 1); } 315 316/* 317 * Compute the amount of space available 318 * before the current start of data in an mbuf. 319 */ 320#define M_LEADINGSPACE(m) \ 321 ((m)->m_flags & M_EXT ? /* (m)->m_data - (m)->m_ext.ext_buf */ 0 : \ 322 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \ 323 (m)->m_data - (m)->m_dat) 324 325/* 326 * Compute the amount of space available 327 * after the end of data in an mbuf. 328 */ 329#define M_TRAILINGSPACE(m) \ 330 ((m)->m_flags & M_EXT ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size - \ 331 ((m)->m_data + (m)->m_len) : \ 332 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len)) 333 334/* 335 * Arrange to prepend space of size plen to mbuf m. 336 * If a new mbuf must be allocated, how specifies whether to wait. 337 * If how is M_DONTWAIT and allocation fails, the original mbuf chain 338 * is freed and m is set to NULL. 339 */ 340#define M_PREPEND(m, plen, how) { \ 341 if (M_LEADINGSPACE(m) >= (plen)) { \ 342 (m)->m_data -= (plen); \ 343 (m)->m_len += (plen); \ 344 } else \ 345 (m) = m_prepend((m), (plen), (how)); \ 346 if ((m) && (m)->m_flags & M_PKTHDR) \ 347 (m)->m_pkthdr.len += (plen); \ 348} 349 350/* change mbuf to new type */ 351#define MCHTYPE(m, t) { \ 352 MBUFLOCK(mbstat.m_mtypes[(m)->m_type]--; mbstat.m_mtypes[t]++;) \ 353 (m)->m_type = t;\ 354} 355 356/* length to m_copy to copy all */ 357#define M_COPYALL 1000000000 358 359/* compatibility with 4.3 */ 360#define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT) 361 362/* 363 * Mbuf statistics. 364 */ 365struct mbstat { 366 u_long m_mbufs; /* mbufs obtained from page pool */ 367 u_long m_clusters; /* clusters obtained from page pool */ 368 u_long m_spare; /* spare field */ 369 u_long m_clfree; /* free clusters */ 370 u_long m_drops; /* times failed to find space */ 371 u_long m_wait; /* times waited for space */ 372 u_long m_drain; /* times drained protocols for space */ 373 u_short m_mtypes[256]; /* type specific mbuf allocations */ 374 u_long m_mcfail; /* times m_copym failed */ 375 u_long m_mpfail; /* times m_pullup failed */ 376 u_long m_msize; /* length of an mbuf */ 377 u_long m_mclbytes; /* length of an mbuf cluster */ 378 u_long m_minclsize; /* min length of data to allocate a cluster */ 379 u_long m_mlen; /* length of data in an mbuf */ 380 u_long m_mhlen; /* length of data in a header mbuf */ 381}; 382 383#ifdef KERNEL 384extern struct mbuf *mbutl; /* virtual address of mclusters */ 385extern char *mclrefcnt; /* cluster reference counts */ 386extern struct mbstat mbstat; 387extern int nmbclusters; 388extern int nmbufs; 389extern struct mbuf *mmbfree; 390extern union mcluster *mclfree; 391extern int max_linkhdr; /* largest link-level header */ 392extern int max_protohdr; /* largest protocol header */ 393extern int max_hdr; /* largest link+protocol header */ 394extern int max_datalen; /* MHLEN - max_hdr */ 395 396struct mbuf *m_copym __P((struct mbuf *, int, int, int)); 397struct mbuf *m_copypacket __P((struct mbuf *, int)); 398struct mbuf *m_devget __P((char *, int, int, struct ifnet *, 399 void (*copy)(char *, caddr_t, u_int))); 400struct mbuf *m_free __P((struct mbuf *)); 401struct mbuf *m_get __P((int, int)); 402struct mbuf *m_getclr __P((int, int)); 403struct mbuf *m_gethdr __P((int, int)); 404struct mbuf *m_prepend __P((struct mbuf *,int,int)); 405struct mbuf *m_pullup __P((struct mbuf *, int)); 406struct mbuf *m_retry __P((int, int)); 407struct mbuf *m_retryhdr __P((int, int)); 408struct mbuf *m_split __P((struct mbuf *,int,int)); 409void m_adj __P((struct mbuf *, int)); 410void m_cat __P((struct mbuf *,struct mbuf *)); 411int m_mballoc __P((int, int)); 412int m_clalloc __P((int, int)); 413void m_copyback __P((struct mbuf *, int, int, caddr_t)); 414void m_copydata __P((struct mbuf *,int,int,caddr_t)); 415void m_freem __P((struct mbuf *)); 416#endif /* KERNEL */ 417 418#endif /* !_SYS_MBUF_H_ */ 419