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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29#ifndef _FBSD_COMPAT_SYS_MBUF_FBSD_H_ 30#define _FBSD_COMPAT_SYS_MBUF_FBSD_H_ 31 32/* 33 * Return the address of the start of the buffer associated with an mbuf, 34 * handling external storage, packet-header mbufs, and regular data mbufs. 35 */ 36#define M_START(m) \ 37 (((m)->m_flags & M_EXT) ? (m)->m_ext.ext_buf : \ 38 ((m)->m_flags & M_PKTHDR) ? &(m)->m_pktdat[0] : \ 39 &(m)->m_dat[0]) 40 41/* 42 * Return the size of the buffer associated with an mbuf, handling external 43 * storage, packet-header mbufs, and regular data mbufs. 44 */ 45#define M_SIZE(m) \ 46 (((m)->m_flags & M_EXT) ? (m)->m_ext.ext_size : \ 47 ((m)->m_flags & M_PKTHDR) ? MHLEN : \ 48 MLEN) 49 50/* 51 * Set the m_data pointer of a newly allocated mbuf to place an object of the 52 * specified size at the end of the mbuf, longword aligned. 53 * 54 * NB: Historically, we had M_ALIGN(), MH_ALIGN(), and MEXT_ALIGN() as 55 * separate macros, each asserting that it was called at the proper moment. 56 * This required callers to themselves test the storage type and call the 57 * right one. Rather than require callers to be aware of those layout 58 * decisions, we centralize here. 59 */ 60static __inline void 61m_align(struct mbuf *m, int len) 62{ 63#ifdef INVARIANTS 64 const char *msg = "%s: not a virgin mbuf"; 65#endif 66 int adjust; 67 68 KASSERT(m->m_data == M_START(m), (msg, __func__)); 69 70 adjust = M_SIZE(m) - len; 71 m->m_data += adjust &~ (sizeof(long)-1); 72} 73 74#define M_ALIGN(m, len) m_align(m, len) 75#define MH_ALIGN(m, len) m_align(m, len) 76#define MEXT_ALIGN(m, len) m_align(m, len) 77 78/* 79 * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can 80 * be both the local data payload, or an external buffer area, depending on 81 * whether M_EXT is set). 82 */ 83#define M_WRITABLE(m) (!((m)->m_flags & M_RDONLY) && \ 84 (!(((m)->m_flags & M_EXT)) || \ 85 (m_extrefcnt(m) == 1))) 86 87/* 88 * Compute the amount of space available before the current start of data in 89 * an mbuf. 90 * 91 * The M_WRITABLE() is a temporary, conservative safety measure: the burden 92 * of checking writability of the mbuf data area rests solely with the caller. 93 * 94 * NB: In previous versions, M_LEADINGSPACE() would only check M_WRITABLE() 95 * for mbufs with external storage. We now allow mbuf-embedded data to be 96 * read-only as well. 97 */ 98#define M_LEADINGSPACE(m) \ 99 (M_WRITABLE(m) ? ((m)->m_data - M_START(m)) : 0) 100 101/* 102 * Compute the amount of space available after the end of data in an mbuf. 103 * 104 * The M_WRITABLE() is a temporary, conservative safety measure: the burden 105 * of checking writability of the mbuf data area rests solely with the caller. 106 * 107 * NB: In previous versions, M_TRAILINGSPACE() would only check M_WRITABLE() 108 * for mbufs with external storage. We now allow mbuf-embedded data to be 109 * read-only as well. 110 */ 111#define M_TRAILINGSPACE(m) \ 112 (M_WRITABLE(m) ? \ 113 ((M_START(m) + M_SIZE(m)) - ((m)->m_data + (m)->m_len)) : 0) 114 115/* 116 * Arrange to prepend space of size plen to mbuf m. 117 * If a new mbuf must be allocated, how specifies whether to wait. 118 * If the allocation fails, the original mbuf chain is freed and m is 119 * set to NULL. 120 */ 121#define M_PREPEND(m, plen, how) do { \ 122 struct mbuf **_mmp = &(m); \ 123 struct mbuf *_mm = *_mmp; \ 124 int _mplen = (plen); \ 125 int __mhow = (how); \ 126 \ 127 MBUF_CHECKSLEEP(how); \ 128 if (M_LEADINGSPACE(_mm) >= _mplen) { \ 129 _mm->m_data -= _mplen; \ 130 _mm->m_len += _mplen; \ 131 } else \ 132 _mm = m_prepend(_mm, _mplen, __mhow); \ 133 if (_mm != NULL && _mm->m_flags & M_PKTHDR) \ 134 _mm->m_pkthdr.len += _mplen; \ 135 *_mmp = _mm; \ 136} while (0) 137 138static __inline void 139m_clrprotoflags(struct mbuf *m) 140{ 141 while (m) { 142 m->m_flags &= ~M_PROTOFLAGS; 143 m = m->m_next; 144 } 145} 146 147static inline u_int 148m_extrefcnt(struct mbuf *m) 149{ 150 KASSERT(m->m_flags & M_EXT, ("%s: M_EXT missing", __func__)); 151 152 return ((m->m_ext.ext_flags & EXT_FLAG_EMBREF) ? m->m_ext.ext_count : 153 *m->m_ext.ext_cnt); 154} 155 156static __inline int 157m_gettype(int size) 158{ 159 int type = 0; 160 161 switch (size) { 162 case MCLBYTES: 163 type = EXT_CLUSTER; 164 break; 165#if MJUMPAGESIZE != MCLBYTES 166 case MJUMPAGESIZE: 167 type = EXT_JUMBOP; 168 break; 169#endif 170 case MJUM9BYTES: 171 type = EXT_JUMBO9; 172 break; 173 default: 174 panic("%s: invalid cluster size %d", __func__, size); 175 } 176 177 return (type); 178} 179 180/* 181 * XXX: m_cljset() is a dangerous API. One must attach only a new, 182 * unreferenced cluster to an mbuf(9). It is not possible to assert 183 * that, so care can be taken only by users of the API. 184 */ 185static __inline void 186m_cljset(struct mbuf *m, void *cl, int type) 187{ 188 int size = 0; 189 190 switch (type) { 191 case EXT_CLUSTER: 192 size = MCLBYTES; 193 break; 194#if MJUMPAGESIZE != MCLBYTES 195 case EXT_JUMBOP: 196 size = MJUMPAGESIZE; 197 break; 198#endif 199 case EXT_JUMBO9: 200 size = MJUM9BYTES; 201 break; 202 default: 203 panic("%s: unknown cluster type %d", __func__, type); 204 break; 205 } 206 207 m->m_data = m->m_ext.ext_buf = (caddr_t)cl; 208 m->m_ext.ext_size = size; 209 m->m_ext.ext_type = type; 210 m->m_ext.ext_flags = EXT_FLAG_EMBREF; 211 m->m_ext.ext_count = 1; 212 m->m_flags |= M_EXT; 213} 214 215/* These are for OpenBSD compatibility. */ 216#define MTAG_ABI_COMPAT 0 /* compatibility ABI */ 217 218static __inline struct m_tag * 219m_tag_find(struct mbuf *m, uint16_t type, struct m_tag *start) 220{ 221 return (SLIST_EMPTY(&m->m_pkthdr.tags) ? (struct m_tag *)NULL : 222 m_tag_locate(m, MTAG_ABI_COMPAT, type, start)); 223} 224 225/* mbufq */ 226 227struct mbufq { 228 STAILQ_HEAD(, mbuf) mq_head; 229 int mq_len; 230 int mq_maxlen; 231}; 232 233static inline void 234mbufq_init(struct mbufq *mq, int maxlen) 235{ 236 STAILQ_INIT(&mq->mq_head); 237 mq->mq_maxlen = maxlen; 238 mq->mq_len = 0; 239} 240 241static inline struct mbuf * 242mbufq_flush(struct mbufq *mq) 243{ 244 struct mbuf *m; 245 246 m = STAILQ_FIRST(&mq->mq_head); 247 STAILQ_INIT(&mq->mq_head); 248 mq->mq_len = 0; 249 return (m); 250} 251 252static inline void 253mbufq_drain(struct mbufq *mq) 254{ 255 struct mbuf *m, *n; 256 257 n = mbufq_flush(mq); 258 while ((m = n) != NULL) { 259 n = STAILQ_NEXT(m, m_stailqpkt); 260 m_freem(m); 261 } 262} 263 264static inline struct mbuf * 265mbufq_first(const struct mbufq *mq) 266{ 267 return (STAILQ_FIRST(&mq->mq_head)); 268} 269 270static inline struct mbuf * 271mbufq_last(const struct mbufq *mq) 272{ 273 return (STAILQ_LAST(&mq->mq_head, mbuf, m_stailqpkt)); 274} 275 276static inline int 277mbufq_full(const struct mbufq *mq) 278{ 279 return (mq->mq_len >= mq->mq_maxlen); 280} 281 282static inline int 283mbufq_len(const struct mbufq *mq) 284{ 285 return (mq->mq_len); 286} 287 288static inline int 289mbufq_enqueue(struct mbufq *mq, struct mbuf *m) 290{ 291 292 if (mbufq_full(mq)) 293 return (ENOBUFS); 294 STAILQ_INSERT_TAIL(&mq->mq_head, m, m_stailqpkt); 295 mq->mq_len++; 296 return (0); 297} 298 299static inline struct mbuf * 300mbufq_dequeue(struct mbufq *mq) 301{ 302 struct mbuf *m; 303 304 m = STAILQ_FIRST(&mq->mq_head); 305 if (m) { 306 STAILQ_REMOVE_HEAD(&mq->mq_head, m_stailqpkt); 307 m->m_nextpkt = NULL; 308 mq->mq_len--; 309 } 310 return (m); 311} 312 313static inline void 314mbufq_prepend(struct mbufq *mq, struct mbuf *m) 315{ 316 317 STAILQ_INSERT_HEAD(&mq->mq_head, m, m_stailqpkt); 318 mq->mq_len++; 319} 320 321 322/* 323 * Note: this doesn't enforce the maximum list size for dst. 324 */ 325static inline void 326mbufq_concat(struct mbufq *mq_dst, struct mbufq *mq_src) 327{ 328 329 mq_dst->mq_len += mq_src->mq_len; 330 STAILQ_CONCAT(&mq_dst->mq_head, &mq_src->mq_head); 331 mq_src->mq_len = 0; 332} 333 334#endif 335