1 /* $OpenBSD: uipc_mbuf2.c,v 1.47 2024/08/29 16:42:30 bluhm Exp $ */ 2 /* $KAME: uipc_mbuf2.c,v 1.29 2001/02/14 13:42:10 itojun Exp $ */ 3 /* $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $ */ 4 5 /* 6 * Copyright (C) 1999 WIDE Project. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the project 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 PROJECT 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 PROJECT 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 34 /* 35 * Copyright (c) 1982, 1986, 1988, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. Neither the name of the University nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 * SUCH DAMAGE. 61 * 62 * @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95 63 */ 64 65 #include <sys/param.h> 66 #include <sys/systm.h> 67 #include <sys/malloc.h> 68 #include <sys/pool.h> 69 #include <sys/percpu.h> 70 #include <sys/mbuf.h> 71 72 extern struct pool mtagpool; 73 74 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ 75 static struct mbuf *m_dup1(struct mbuf *, int, int, int); 76 77 /* 78 * ensure that [off, off + len] is contiguous on the mbuf chain "m". 79 * packet chain before "off" is kept untouched. 80 * if offp == NULL, the target will start at <retval, 0> on resulting chain. 81 * if offp != NULL, the target will start at <retval, *offp> on resulting chain. 82 * 83 * on error return (NULL return value), original "m" will be freed. 84 * 85 * XXX m_trailingspace/m_leadingspace on shared cluster (sharedcluster) 86 */ 87 struct mbuf * 88 m_pulldown(struct mbuf *m, int off, int len, int *offp) 89 { 90 struct mbuf *n, *o; 91 int hlen, tlen, olen; 92 int sharedcluster; 93 94 /* check invalid arguments. */ 95 if (m == NULL) 96 panic("m == NULL in m_pulldown()"); 97 98 if ((n = m_getptr(m, off, &off)) == NULL) { 99 m_freem(m); 100 return (NULL); /* mbuf chain too short */ 101 } 102 103 sharedcluster = M_READONLY(n); 104 105 /* 106 * the target data is on <n, off>. 107 * if we got enough data on the mbuf "n", we're done. 108 */ 109 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) 110 goto ok; 111 112 /* 113 * when len <= n->m_len - off and off != 0, it is a special case. 114 * len bytes from <n, off> sits in single mbuf, but the caller does 115 * not like the starting position (off). 116 * chop the current mbuf into two pieces, set off to 0. 117 */ 118 if (len <= n->m_len - off) { 119 struct mbuf *mlast; 120 121 counters_inc(mbstat, MBSTAT_PULLDOWN_ALLOC); 122 o = m_dup1(n, off, n->m_len - off, M_DONTWAIT); 123 if (o == NULL) { 124 m_freem(m); 125 return (NULL); /* ENOBUFS */ 126 } 127 for (mlast = o; mlast->m_next != NULL; mlast = mlast->m_next) 128 ; 129 n->m_len = off; 130 mlast->m_next = n->m_next; 131 n->m_next = o; 132 n = o; 133 off = 0; 134 goto ok; 135 } 136 137 /* 138 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, 139 * and construct contiguous mbuf with m_len == len. 140 * note that hlen + tlen == len, and tlen > 0. 141 */ 142 hlen = n->m_len - off; 143 tlen = len - hlen; 144 145 /* 146 * ensure that we have enough trailing data on mbuf chain. 147 * if not, we can do nothing about the chain. 148 */ 149 olen = 0; 150 for (o = n->m_next; o != NULL; o = o->m_next) 151 olen += o->m_len; 152 if (hlen + olen < len) { 153 m_freem(m); 154 return (NULL); /* mbuf chain too short */ 155 } 156 157 /* 158 * easy cases first. 159 * we need to use m_copydata() to get data from <n->m_next, 0>. 160 */ 161 if ((off == 0 || offp) && m_trailingspace(n) >= tlen && 162 !sharedcluster) { 163 counters_inc(mbstat, MBSTAT_PULLDOWN_COPY); 164 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); 165 n->m_len += tlen; 166 m_adj(n->m_next, tlen); 167 goto ok; 168 } 169 if ((off == 0 || offp) && m_leadingspace(n->m_next) >= hlen && 170 !sharedcluster && n->m_next->m_len >= tlen) { 171 n->m_next->m_data -= hlen; 172 n->m_next->m_len += hlen; 173 counters_inc(mbstat, MBSTAT_PULLDOWN_COPY); 174 memcpy(mtod(n->m_next, caddr_t), mtod(n, caddr_t) + off, hlen); 175 n->m_len -= hlen; 176 n = n->m_next; 177 off = 0; 178 goto ok; 179 } 180 181 /* 182 * now, we need to do the hard way. don't m_copym as there's no room 183 * on both ends. 184 */ 185 if (len > MAXMCLBYTES) { 186 m_freem(m); 187 return (NULL); 188 } 189 counters_inc(mbstat, MBSTAT_PULLDOWN_ALLOC); 190 MGET(o, M_DONTWAIT, m->m_type); 191 if (o && len > MLEN) { 192 MCLGETL(o, M_DONTWAIT, len); 193 if ((o->m_flags & M_EXT) == 0) { 194 m_free(o); 195 o = NULL; 196 } 197 } 198 if (!o) { 199 m_freem(m); 200 return (NULL); /* ENOBUFS */ 201 } 202 /* get hlen from <n, off> into <o, 0> */ 203 o->m_len = hlen; 204 memcpy(mtod(o, caddr_t), mtod(n, caddr_t) + off, hlen); 205 n->m_len -= hlen; 206 /* get tlen from <n->m_next, 0> into <o, hlen> */ 207 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); 208 o->m_len += tlen; 209 m_adj(n->m_next, tlen); 210 o->m_next = n->m_next; 211 n->m_next = o; 212 n = o; 213 off = 0; 214 215 ok: 216 if (offp) 217 *offp = off; 218 return (n); 219 } 220 221 static struct mbuf * 222 m_dup1(struct mbuf *m, int off, int len, int wait) 223 { 224 struct mbuf *n; 225 int l; 226 227 if (len > MAXMCLBYTES) 228 return (NULL); 229 if (off == 0 && (m->m_flags & M_PKTHDR) != 0) { 230 MGETHDR(n, wait, m->m_type); 231 if (n == NULL) 232 return (NULL); 233 if (m_dup_pkthdr(n, m, wait)) { 234 m_free(n); 235 return (NULL); 236 } 237 l = MHLEN; 238 } else { 239 MGET(n, wait, m->m_type); 240 l = MLEN; 241 } 242 if (n && len > l) { 243 MCLGETL(n, wait, len); 244 if ((n->m_flags & M_EXT) == 0) { 245 m_free(n); 246 n = NULL; 247 } 248 } 249 if (!n) 250 return (NULL); 251 252 m_copydata(m, off, len, mtod(n, caddr_t)); 253 n->m_len = len; 254 255 return (n); 256 } 257 258 /* Get a packet tag structure along with specified data following. */ 259 struct m_tag * 260 m_tag_get(int type, int len, int wait) 261 { 262 struct m_tag *t; 263 264 if (len < 0) 265 return (NULL); 266 if (len > PACKET_TAG_MAXSIZE) 267 panic("requested tag size for pool %#x is too big", type); 268 t = pool_get(&mtagpool, wait == M_WAITOK ? PR_WAITOK : PR_NOWAIT); 269 if (t == NULL) 270 return (NULL); 271 t->m_tag_id = type; 272 t->m_tag_len = len; 273 return (t); 274 } 275 276 /* Prepend a packet tag. */ 277 void 278 m_tag_prepend(struct mbuf *m, struct m_tag *t) 279 { 280 SLIST_INSERT_HEAD(&m->m_pkthdr.ph_tags, t, m_tag_link); 281 m->m_pkthdr.ph_tagsset |= t->m_tag_id; 282 } 283 284 /* Unlink and free a packet tag. */ 285 void 286 m_tag_delete(struct mbuf *m, struct m_tag *t) 287 { 288 u_int32_t ph_tagsset = 0; 289 struct m_tag *p; 290 291 SLIST_REMOVE(&m->m_pkthdr.ph_tags, t, m_tag, m_tag_link); 292 pool_put(&mtagpool, t); 293 294 SLIST_FOREACH(p, &m->m_pkthdr.ph_tags, m_tag_link) 295 ph_tagsset |= p->m_tag_id; 296 m->m_pkthdr.ph_tagsset = ph_tagsset; 297 298 } 299 300 /* Unlink and free a packet tag chain. */ 301 void 302 m_tag_delete_chain(struct mbuf *m) 303 { 304 struct m_tag *p; 305 306 while ((p = SLIST_FIRST(&m->m_pkthdr.ph_tags)) != NULL) { 307 SLIST_REMOVE_HEAD(&m->m_pkthdr.ph_tags, m_tag_link); 308 pool_put(&mtagpool, p); 309 } 310 m->m_pkthdr.ph_tagsset = 0; 311 } 312 313 /* Find a tag, starting from a given position. */ 314 struct m_tag * 315 m_tag_find(struct mbuf *m, int type, struct m_tag *t) 316 { 317 struct m_tag *p; 318 319 if (!(m->m_pkthdr.ph_tagsset & type)) 320 return (NULL); 321 322 if (t == NULL) 323 p = SLIST_FIRST(&m->m_pkthdr.ph_tags); 324 else 325 p = SLIST_NEXT(t, m_tag_link); 326 while (p != NULL) { 327 if (p->m_tag_id == type) 328 return (p); 329 p = SLIST_NEXT(p, m_tag_link); 330 } 331 return (NULL); 332 } 333 334 /* Copy a single tag. */ 335 struct m_tag * 336 m_tag_copy(struct m_tag *t, int wait) 337 { 338 struct m_tag *p; 339 340 p = m_tag_get(t->m_tag_id, t->m_tag_len, wait); 341 if (p == NULL) 342 return (NULL); 343 memcpy(p + 1, t + 1, t->m_tag_len); /* Copy the data */ 344 return (p); 345 } 346 347 /* 348 * Copy two tag chains. The destination mbuf (to) loses any attached 349 * tags even if the operation fails. This should not be a problem, as 350 * m_tag_copy_chain() is typically called with a newly-allocated 351 * destination mbuf. 352 */ 353 int 354 m_tag_copy_chain(struct mbuf *to, struct mbuf *from, int wait) 355 { 356 struct m_tag *p, *t, *tprev = NULL; 357 358 m_tag_delete_chain(to); 359 SLIST_FOREACH(p, &from->m_pkthdr.ph_tags, m_tag_link) { 360 t = m_tag_copy(p, wait); 361 if (t == NULL) { 362 m_tag_delete_chain(to); 363 return (ENOBUFS); 364 } 365 if (tprev == NULL) 366 SLIST_INSERT_HEAD(&to->m_pkthdr.ph_tags, t, m_tag_link); 367 else 368 SLIST_INSERT_AFTER(tprev, t, m_tag_link); 369 tprev = t; 370 to->m_pkthdr.ph_tagsset |= t->m_tag_id; 371 } 372 return (0); 373 } 374 375 /* Initialize tags on an mbuf. */ 376 void 377 m_tag_init(struct mbuf *m) 378 { 379 SLIST_INIT(&m->m_pkthdr.ph_tags); 380 } 381 382 /* Get first tag in chain. */ 383 struct m_tag * 384 m_tag_first(struct mbuf *m) 385 { 386 return (SLIST_FIRST(&m->m_pkthdr.ph_tags)); 387 } 388 389 /* Get next tag in chain. */ 390 struct m_tag * 391 m_tag_next(struct mbuf *m, struct m_tag *t) 392 { 393 return (SLIST_NEXT(t, m_tag_link)); 394 } 395