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 * $FreeBSD$ 35 */ 36 37 #ifndef _SYS_MBUF_H_ 38 #define _SYS_MBUF_H_ 39 40 /* 41 * Mbufs are of a single size, MSIZE (machine/param.h), which 42 * includes overhead. An mbuf may add a single "mbuf cluster" of size 43 * MCLBYTES (also in machine/param.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. Additionally, it is possible 46 * to allocate a separate buffer externally and attach it to the mbuf in 47 * a way similar to that of mbuf clusters. 48 */ 49 #define MLEN (MSIZE - sizeof(struct m_hdr)) /* normal data len */ 50 #define MHLEN (MLEN - sizeof(struct pkthdr)) /* data len w/pkthdr */ 51 #define MINCLSIZE (MHLEN + 1) /* smallest amount to put in cluster */ 52 #define M_MAXCOMPRESS (MHLEN / 2) /* max amount to copy for compression */ 53 54 #ifdef _KERNEL 55 /*- 56 * Macros for type conversion: 57 * mtod(m, t) -- Convert mbuf pointer to data pointer of correct type. 58 * dtom(x) -- Convert data pointer within mbuf to mbuf pointer (XXX). 59 */ 60 #define mtod(m, t) ((t)((m)->m_data)) 61 #define dtom(x) ((struct mbuf *)((intptr_t)(x) & ~(MSIZE-1))) 62 #endif /* _KERNEL */ 63 64 /* 65 * Header present at the beginning of every mbuf. 66 */ 67 struct m_hdr { 68 struct mbuf *mh_next; /* next buffer in chain */ 69 struct mbuf *mh_nextpkt; /* next chain in queue/record */ 70 caddr_t mh_data; /* location of data */ 71 int mh_len; /* amount of data in this mbuf */ 72 short mh_type; /* type of data in this mbuf */ 73 short mh_flags; /* flags; see below */ 74 }; 75 76 /* 77 * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set. 78 */ 79 struct pkthdr { 80 struct ifnet *rcvif; /* rcv interface */ 81 int len; /* total packet length */ 82 /* variables for ip and tcp reassembly */ 83 void *header; /* pointer to packet header */ 84 /* variables for hardware checksum */ 85 int csum_flags; /* flags regarding checksum */ 86 int csum_data; /* data field used by csum routines */ 87 struct mbuf *aux; /* extra data buffer; ipsec/others */ 88 }; 89 90 /* 91 * Description of external storage mapped into mbuf; valid only if M_EXT is set. 92 */ 93 struct m_ext { 94 caddr_t ext_buf; /* start of buffer */ 95 void (*ext_free) /* free routine if not the usual */ 96 (caddr_t, void *); 97 void *ext_args; /* optional argument pointer */ 98 u_int ext_size; /* size of buffer, for ext_free */ 99 u_int *ref_cnt; /* pointer to ref count info */ 100 int ext_type; /* type of external storage */ 101 }; 102 103 /* 104 * The core of the mbuf object along with some shortcut defines for 105 * practical purposes. 106 */ 107 struct mbuf { 108 struct m_hdr m_hdr; 109 union { 110 struct { 111 struct pkthdr MH_pkthdr; /* M_PKTHDR set */ 112 union { 113 struct m_ext MH_ext; /* M_EXT set */ 114 char MH_databuf[MHLEN]; 115 } MH_dat; 116 } MH; 117 char M_databuf[MLEN]; /* !M_PKTHDR, !M_EXT */ 118 } M_dat; 119 }; 120 #define m_next m_hdr.mh_next 121 #define m_len m_hdr.mh_len 122 #define m_data m_hdr.mh_data 123 #define m_type m_hdr.mh_type 124 #define m_flags m_hdr.mh_flags 125 #define m_nextpkt m_hdr.mh_nextpkt 126 #define m_act m_nextpkt 127 #define m_pkthdr M_dat.MH.MH_pkthdr 128 #define m_ext M_dat.MH.MH_dat.MH_ext 129 #define m_pktdat M_dat.MH.MH_dat.MH_databuf 130 #define m_dat M_dat.M_databuf 131 132 /* 133 * mbuf flags. 134 */ 135 #define M_EXT 0x0001 /* has associated external storage */ 136 #define M_PKTHDR 0x0002 /* start of record */ 137 #define M_EOR 0x0004 /* end of record */ 138 #define M_RDONLY 0x0008 /* associated data is marked read-only */ 139 #define M_PROTO1 0x0010 /* protocol-specific */ 140 #define M_PROTO2 0x0020 /* protocol-specific */ 141 #define M_PROTO3 0x0040 /* protocol-specific */ 142 #define M_PROTO4 0x0080 /* protocol-specific */ 143 #define M_PROTO5 0x0100 /* protocol-specific */ 144 145 /* 146 * mbuf pkthdr flags (also stored in m_flags). 147 */ 148 #define M_BCAST 0x0200 /* send/received as link-level broadcast */ 149 #define M_MCAST 0x0400 /* send/received as link-level multicast */ 150 #define M_FRAG 0x0800 /* packet is a fragment of a larger packet */ 151 #define M_FIRSTFRAG 0x1000 /* packet is first fragment */ 152 #define M_LASTFRAG 0x2000 /* packet is last fragment */ 153 154 /* 155 * External buffer types: identify ext_buf type. 156 */ 157 #define EXT_CLUSTER 1 /* mbuf cluster */ 158 #define EXT_SFBUF 2 /* sendfile(2)'s sf_bufs */ 159 #define EXT_NET_DRV 100 /* custom ext_buf provided by net driver(s) */ 160 #define EXT_MOD_TYPE 200 /* custom module's ext_buf type */ 161 162 /* 163 * Flags copied when copying m_pkthdr. 164 */ 165 #define M_COPYFLAGS (M_PKTHDR|M_EOR|M_PROTO1|M_PROTO1|M_PROTO2|M_PROTO3 | \ 166 M_PROTO4|M_PROTO5|M_BCAST|M_MCAST|M_FRAG|M_RDONLY) 167 168 /* 169 * Flags indicating hw checksum support and sw checksum requirements. 170 */ 171 #define CSUM_IP 0x0001 /* will csum IP */ 172 #define CSUM_TCP 0x0002 /* will csum TCP */ 173 #define CSUM_UDP 0x0004 /* will csum UDP */ 174 #define CSUM_IP_FRAGS 0x0008 /* will csum IP fragments */ 175 #define CSUM_FRAGMENT 0x0010 /* will do IP fragmentation */ 176 177 #define CSUM_IP_CHECKED 0x0100 /* did csum IP */ 178 #define CSUM_IP_VALID 0x0200 /* ... the csum is valid */ 179 #define CSUM_DATA_VALID 0x0400 /* csum_data field is valid */ 180 #define CSUM_PSEUDO_HDR 0x0800 /* csum_data has pseudo hdr */ 181 182 #define CSUM_DELAY_DATA (CSUM_TCP | CSUM_UDP) 183 #define CSUM_DELAY_IP (CSUM_IP) /* XXX add ipv6 here too? */ 184 185 /* 186 * mbuf types. 187 */ 188 #define MT_NOTMBUF 0 /* USED INTERNALLY ONLY! Object is not mbuf */ 189 #define MT_DATA 1 /* dynamic (data) allocation */ 190 #define MT_HEADER 2 /* packet header */ 191 #if 0 192 #define MT_SOCKET 3 /* socket structure */ 193 #define MT_PCB 4 /* protocol control block */ 194 #define MT_RTABLE 5 /* routing tables */ 195 #define MT_HTABLE 6 /* IMP host tables */ 196 #define MT_ATABLE 7 /* address resolution tables */ 197 #endif 198 #define MT_SONAME 8 /* socket name */ 199 #if 0 200 #define MT_SOOPTS 10 /* socket options */ 201 #endif 202 #define MT_FTABLE 11 /* fragment reassembly header */ 203 #if 0 204 #define MT_RIGHTS 12 /* access rights */ 205 #define MT_IFADDR 13 /* interface address */ 206 #endif 207 #define MT_CONTROL 14 /* extra-data protocol message */ 208 #define MT_OOBDATA 15 /* expedited data */ 209 #define MT_NTYPES 16 /* number of mbuf types for mbtypes[] */ 210 211 /* 212 * Mbuf and cluster allocation statistics PCPU structure. 213 */ 214 struct mbpstat { 215 u_long mb_mbfree; 216 u_long mb_mbpgs; 217 u_long mb_clfree; 218 u_long mb_clpgs; 219 long mb_mbtypes[MT_NTYPES]; 220 short mb_active; 221 }; 222 223 /* 224 * General mbuf allocator statistics structure. 225 * XXX: Modifications of these are not protected by any mutex locks nor by 226 * any atomic() manipulations. As a result, we may occasionally lose 227 * a count or two. Luckily, not all of these fields are modified at all 228 * and remain static, and those that are manipulated are only manipulated 229 * in failure situations, which do not occur (hopefully) very often. 230 */ 231 struct mbstat { 232 u_long m_drops; /* times failed to allocate */ 233 u_long m_wait; /* times succesfully returned from wait */ 234 u_long m_drain; /* times drained protocols for space */ 235 u_long m_mcfail; /* XXX: times m_copym failed */ 236 u_long m_mpfail; /* XXX: times m_pullup failed */ 237 u_long m_msize; /* length of an mbuf */ 238 u_long m_mclbytes; /* length of an mbuf cluster */ 239 u_long m_minclsize; /* min length of data to allocate a cluster */ 240 u_long m_mlen; /* length of data in an mbuf */ 241 u_long m_mhlen; /* length of data in a header mbuf */ 242 /* Number of mbtypes (gives # elems in mbpstat's mb_mbtypes[] array: */ 243 short m_numtypes; 244 }; 245 246 /* 247 * Flags specifying how an allocation should be made. 248 * M_DONTWAIT means "don't block if nothing is available" whereas 249 * M_TRYWAIT means "block for mbuf_wait ticks at most if nothing is 250 * available." 251 */ 252 #define M_DONTWAIT 1 253 #define M_TRYWAIT 0 254 #define M_WAIT M_TRYWAIT /* XXX: Deprecated. */ 255 256 #ifdef _KERNEL 257 /*- 258 * mbuf external reference count management macros. 259 * 260 * MEXT_IS_REF(m): true if (m) is not the only mbuf referencing 261 * the external buffer ext_buf. 262 * 263 * MEXT_REM_REF(m): remove reference to m_ext object. 264 * 265 * MEXT_ADD_REF(m): add reference to m_ext object already 266 * referred to by (m). 267 */ 268 #define MEXT_IS_REF(m) (*((m)->m_ext.ref_cnt) > 1) 269 270 #define MEXT_REM_REF(m) do { \ 271 KASSERT(*((m)->m_ext.ref_cnt) > 0, ("m_ext refcnt < 0")); \ 272 atomic_subtract_int((m)->m_ext.ref_cnt, 1); \ 273 } while(0) 274 275 #define MEXT_ADD_REF(m) atomic_add_int((m)->m_ext.ref_cnt, 1) 276 277 /* 278 * mbuf, cluster, and external object allocation macros 279 * (for compatibility purposes). 280 */ 281 #define m_getclr m_get_clrd 282 #define MGET(m, how, type) (m) = m_get((how), (type)) 283 #define MGETHDR(m, how, type) (m) = m_gethdr((how), (type)) 284 #define MCLGET(m, how) m_clget((m), (how)) 285 #define MEXTADD(m, buf, size, free, args, flags, type) \ 286 m_extadd((m), (caddr_t)(buf), (size), (free), (args), (flags), (type)) 287 288 /* 289 * MEXTFREE(m): disassociate (and possibly free) an external object from (m). 290 * 291 * If the atomic_cmpset_int() returns 0, then we effectively do nothing 292 * in terms of "cleaning up" (freeing the ext buf and ref. counter) as 293 * this means that either there are still references, or another thread 294 * is taking care of the clean-up. 295 */ 296 #define MEXTFREE(m) do { \ 297 struct mbuf *_mb = (m); \ 298 \ 299 MEXT_REM_REF(_mb); \ 300 if (atomic_cmpset_int(_mb->m_ext.ref_cnt, 0, 1)) \ 301 _mext_free(_mb); \ 302 _mb->m_flags &= ~M_EXT; \ 303 } while (0) 304 305 /* 306 * Evaluate TRUE if it's safe to write to the mbuf m's data region (this 307 * can be both the local data payload, or an external buffer area, 308 * depending on whether M_EXT is set). 309 */ 310 #define M_WRITABLE(m) (!((m)->m_flags & M_RDONLY) && (!((m)->m_flags \ 311 & M_EXT) || !MEXT_IS_REF(m))) 312 313 /*- 314 * Copy mbuf pkthdr from "from" to "to". 315 * "from" must have M_PKTHDR set, and "to" must be empty. 316 * aux pointer will be moved to "to". 317 */ 318 #define M_COPY_PKTHDR(to, from) do { \ 319 struct mbuf *_mfrom = (from); \ 320 struct mbuf *_mto = (to); \ 321 \ 322 _mto->m_data = _mto->m_pktdat; \ 323 _mto->m_flags = _mfrom->m_flags & M_COPYFLAGS; \ 324 _mto->m_pkthdr = _mfrom->m_pkthdr; \ 325 _mfrom->m_pkthdr.aux = NULL; \ 326 } while (0) 327 328 /* 329 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place 330 * an object of the specified size at the end of the mbuf, longword aligned. 331 */ 332 #define M_ALIGN(m, len) do { \ 333 (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1); \ 334 } while (0) 335 336 /* 337 * As above, for mbufs allocated with m_gethdr/MGETHDR 338 * or initialized by M_COPY_PKTHDR. 339 */ 340 #define MH_ALIGN(m, len) do { \ 341 (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1); \ 342 } while (0) 343 344 /* 345 * Compute the amount of space available 346 * before the current start of data in an mbuf. 347 */ 348 #define M_LEADINGSPACE(m) \ 349 ((m)->m_flags & M_EXT ? \ 350 (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0): \ 351 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \ 352 (m)->m_data - (m)->m_dat) 353 354 /* 355 * Compute the amount of space available 356 * after the end of data in an mbuf. 357 */ 358 #define M_TRAILINGSPACE(m) \ 359 ((m)->m_flags & M_EXT ? (m)->m_ext.ext_buf + \ 360 (m)->m_ext.ext_size - ((m)->m_data + (m)->m_len) : \ 361 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len)) 362 363 /* 364 * Arrange to prepend space of size plen to mbuf m. 365 * If a new mbuf must be allocated, how specifies whether to wait. 366 * If the allocation fails, the original mbuf chain is freed and m is 367 * set to NULL. 368 */ 369 #define M_PREPEND(m, plen, how) do { \ 370 struct mbuf **_mmp = &(m); \ 371 struct mbuf *_mm = *_mmp; \ 372 int _mplen = (plen); \ 373 int __mhow = (how); \ 374 \ 375 if (M_LEADINGSPACE(_mm) >= _mplen) { \ 376 _mm->m_data -= _mplen; \ 377 _mm->m_len += _mplen; \ 378 } else \ 379 _mm = m_prepend(_mm, _mplen, __mhow); \ 380 if (_mm != NULL && _mm->m_flags & M_PKTHDR) \ 381 _mm->m_pkthdr.len += _mplen; \ 382 *_mmp = _mm; \ 383 } while (0) 384 385 /* 386 * Change mbuf to new type. 387 * This is a relatively expensive operation and should be avoided. 388 */ 389 #define MCHTYPE(m, t) m_chtype((m), (t)) 390 391 /* Length to m_copy to copy all. */ 392 #define M_COPYALL 1000000000 393 394 /* Compatibility with 4.3 */ 395 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT) 396 397 /* 398 * pkthdr.aux type tags. 399 */ 400 struct mauxtag { 401 int af; 402 int type; 403 void *p; 404 }; 405 406 extern int max_datalen; /* MHLEN - max_hdr */ 407 extern int max_hdr; /* largest link + protocol header */ 408 extern int max_linkhdr; /* largest link-level header */ 409 extern int max_protohdr; /* largest protocol header */ 410 extern struct mbpstat mb_statpcpu[]; /* Per-CPU allocation stats. */ 411 extern struct mbstat mbstat; /* General mbuf stats/infos. */ 412 extern int nmbclusters; /* Maximum number of clusters */ 413 extern int nmbcnt; /* Scale kmem_map for counter space */ 414 extern int nmbufs; /* Maximum number of mbufs */ 415 extern int nsfbufs; /* Number of sendfile(2) bufs */ 416 417 void _mext_free(struct mbuf *); 418 void m_adj(struct mbuf *, int); 419 struct mbuf *m_aux_add(struct mbuf *, int, int); 420 struct mbuf *m_aux_add2(struct mbuf *, int, int, void *); 421 void m_aux_delete(struct mbuf *, struct mbuf *); 422 struct mbuf *m_aux_find(struct mbuf *, int, int); 423 struct mbuf *m_aux_find2(struct mbuf *, int, int, void *); 424 void m_cat(struct mbuf *, struct mbuf *); 425 void m_chtype(struct mbuf *, short); 426 void m_clget(struct mbuf *, int); 427 void m_extadd(struct mbuf *, caddr_t, u_int, 428 void (*free)(caddr_t, void *), void *, short, int); 429 void m_copyback(struct mbuf *, int, int, caddr_t); 430 void m_copydata(const struct mbuf *, int, int, caddr_t); 431 struct mbuf *m_copym(struct mbuf *, int, int, int); 432 struct mbuf *m_copypacket(struct mbuf *, int); 433 struct mbuf *m_devget(char *, int, int, struct ifnet *, 434 void (*copy)(char *, caddr_t, u_int)); 435 struct mbuf *m_dup(struct mbuf *, int); 436 struct mbuf *m_free(struct mbuf *); 437 void m_freem(struct mbuf *); 438 struct mbuf *m_get(int, int); 439 struct mbuf *m_get_clrd(int, int); 440 struct mbuf *m_gethdr(int, int); 441 struct mbuf *m_gethdr_clrd(int, int); 442 struct mbuf *m_getm(struct mbuf *, int, int, int); 443 struct mbuf *m_prepend(struct mbuf *, int, int); 444 void m_print(const struct mbuf *m); 445 struct mbuf *m_pulldown(struct mbuf *, int, int, int *); 446 struct mbuf *m_pullup(struct mbuf *, int); 447 struct mbuf *m_split(struct mbuf *, int, int); 448 #endif /* _KERNEL */ 449 450 #endif /* !_SYS_MBUF_H_ */ 451