1 /* $FreeBSD: src/sys/kern/uipc_mbuf2.c,v 1.2.2.5 2003/01/23 21:06:44 sam Exp $ */ 2 /* $DragonFly: src/sys/kern/uipc_mbuf2.c,v 1.3 2003/07/23 02:30:20 dillon Exp $ */ 3 /* $KAME: uipc_mbuf2.c,v 1.31 2001/11/28 11:08:53 itojun Exp $ */ 4 /* $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $ */ 5 6 /* 7 * Copyright (C) 1999 WIDE Project. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the project nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 /* 36 * Copyright (c) 1982, 1986, 1988, 1991, 1993 37 * The Regents of the University of California. All rights reserved. 38 * 39 * Redistribution and use in source and binary forms, with or without 40 * modification, are permitted provided that the following conditions 41 * are met: 42 * 1. Redistributions of source code must retain the above copyright 43 * notice, this list of conditions and the following disclaimer. 44 * 2. Redistributions in binary form must reproduce the above copyright 45 * notice, this list of conditions and the following disclaimer in the 46 * documentation and/or other materials provided with the distribution. 47 * 3. All advertising materials mentioning features or use of this software 48 * must display the following acknowledgement: 49 * This product includes software developed by the University of 50 * California, Berkeley and its contributors. 51 * 4. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95 68 */ 69 70 /*#define PULLDOWN_DEBUG*/ 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/kernel.h> 75 #include <sys/proc.h> 76 #include <sys/malloc.h> 77 #include <sys/mbuf.h> 78 79 #define M_SHAREDCLUSTER(m) \ 80 (((m)->m_flags & M_EXT) != 0 && \ 81 ((m)->m_ext.ext_free || mclrefcnt[mtocl((m)->m_ext.ext_buf)] > 1)) 82 83 MALLOC_DEFINE(M_PACKET_TAGS, "tag", "packet-attached information"); 84 85 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ 86 static struct mbuf *m_dup1 __P((struct mbuf *, int, int, int)); 87 88 /* 89 * ensure that [off, off + len) is contiguous on the mbuf chain "m". 90 * packet chain before "off" is kept untouched. 91 * if offp == NULL, the target will start at <retval, 0> on resulting chain. 92 * if offp != NULL, the target will start at <retval, *offp> on resulting chain. 93 * 94 * on error return (NULL return value), original "m" will be freed. 95 * 96 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster) 97 */ 98 struct mbuf * 99 m_pulldown(m, off, len, offp) 100 struct mbuf *m; 101 int off, len; 102 int *offp; 103 { 104 struct mbuf *n, *o; 105 int hlen, tlen, olen; 106 int sharedcluster; 107 108 /* check invalid arguments. */ 109 if (m == NULL) 110 panic("m == NULL in m_pulldown()"); 111 if (len > MCLBYTES) { 112 m_freem(m); 113 return NULL; /* impossible */ 114 } 115 116 #ifdef PULLDOWN_DEBUG 117 { 118 struct mbuf *t; 119 printf("before:"); 120 for (t = m; t; t = t->m_next) 121 printf(" %d", t->m_len); 122 printf("\n"); 123 } 124 #endif 125 n = m; 126 while (n != NULL && off > 0) { 127 if (n->m_len > off) 128 break; 129 off -= n->m_len; 130 n = n->m_next; 131 } 132 /* be sure to point non-empty mbuf */ 133 while (n != NULL && n->m_len == 0) 134 n = n->m_next; 135 if (!n) { 136 m_freem(m); 137 return NULL; /* mbuf chain too short */ 138 } 139 140 sharedcluster = M_SHAREDCLUSTER(n); 141 142 /* 143 * the target data is on <n, off>. 144 * if we got enough data on the mbuf "n", we're done. 145 */ 146 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) 147 goto ok; 148 149 /* 150 * when len <= n->m_len - off and off != 0, it is a special case. 151 * len bytes from <n, off> sits in single mbuf, but the caller does 152 * not like the starting position (off). 153 * chop the current mbuf into two pieces, set off to 0. 154 */ 155 if (len <= n->m_len - off) { 156 o = m_dup1(n, off, n->m_len - off, M_DONTWAIT); 157 if (o == NULL) { 158 m_freem(m); 159 return NULL; /* ENOBUFS */ 160 } 161 n->m_len = off; 162 o->m_next = n->m_next; 163 n->m_next = o; 164 n = n->m_next; 165 off = 0; 166 goto ok; 167 } 168 169 /* 170 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, 171 * and construct contiguous mbuf with m_len == len. 172 * note that hlen + tlen == len, and tlen > 0. 173 */ 174 hlen = n->m_len - off; 175 tlen = len - hlen; 176 177 /* 178 * ensure that we have enough trailing data on mbuf chain. 179 * if not, we can do nothing about the chain. 180 */ 181 olen = 0; 182 for (o = n->m_next; o != NULL; o = o->m_next) 183 olen += o->m_len; 184 if (hlen + olen < len) { 185 m_freem(m); 186 return NULL; /* mbuf chain too short */ 187 } 188 189 /* 190 * easy cases first. 191 * we need to use m_copydata() to get data from <n->m_next, 0>. 192 */ 193 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen && 194 !sharedcluster) { 195 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); 196 n->m_len += tlen; 197 m_adj(n->m_next, tlen); 198 goto ok; 199 } 200 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen && 201 !sharedcluster) { 202 n->m_next->m_data -= hlen; 203 n->m_next->m_len += hlen; 204 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen); 205 n->m_len -= hlen; 206 n = n->m_next; 207 off = 0; 208 goto ok; 209 } 210 211 /* 212 * now, we need to do the hard way. don't m_copy as there's no room 213 * on both end. 214 */ 215 MGET(o, M_DONTWAIT, m->m_type); 216 if (o && len > MLEN) { 217 MCLGET(o, M_DONTWAIT); 218 if ((o->m_flags & M_EXT) == 0) { 219 m_free(o); 220 o = NULL; 221 } 222 } 223 if (!o) { 224 m_freem(m); 225 return NULL; /* ENOBUFS */ 226 } 227 /* get hlen from <n, off> into <o, 0> */ 228 o->m_len = hlen; 229 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen); 230 n->m_len -= hlen; 231 /* get tlen from <n->m_next, 0> into <o, hlen> */ 232 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); 233 o->m_len += tlen; 234 m_adj(n->m_next, tlen); 235 o->m_next = n->m_next; 236 n->m_next = o; 237 n = o; 238 off = 0; 239 240 ok: 241 #ifdef PULLDOWN_DEBUG 242 { 243 struct mbuf *t; 244 printf("after:"); 245 for (t = m; t; t = t->m_next) 246 printf("%c%d", t == n ? '*' : ' ', t->m_len); 247 printf(" (off=%d)\n", off); 248 } 249 #endif 250 if (offp) 251 *offp = off; 252 return n; 253 } 254 255 static struct mbuf * 256 m_dup1(m, off, len, wait) 257 struct mbuf *m; 258 int off; 259 int len; 260 int wait; 261 { 262 struct mbuf *n; 263 int l; 264 int copyhdr; 265 266 if (len > MCLBYTES) 267 return NULL; 268 if (off == 0 && (m->m_flags & M_PKTHDR) != 0) { 269 copyhdr = 1; 270 MGETHDR(n, wait, m->m_type); 271 l = MHLEN; 272 } else { 273 copyhdr = 0; 274 MGET(n, wait, m->m_type); 275 l = MLEN; 276 } 277 if (n && len > l) { 278 MCLGET(n, wait); 279 if ((n->m_flags & M_EXT) == 0) { 280 m_free(n); 281 n = NULL; 282 } 283 } 284 if (!n) 285 return NULL; 286 287 if (copyhdr && !m_dup_pkthdr(n, m, wait)) { 288 m_free(n); 289 return NULL; 290 } 291 m_copydata(m, off, len, mtod(n, caddr_t)); 292 return n; 293 } 294 295 /* Get a packet tag structure along with specified data following. */ 296 struct m_tag * 297 m_tag_alloc(u_int32_t cookie, int type, int len, int wait) 298 { 299 struct m_tag *t; 300 301 if (len < 0) 302 return NULL; 303 t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait); 304 if (t == NULL) 305 return NULL; 306 t->m_tag_id = type; 307 t->m_tag_len = len; 308 t->m_tag_cookie = cookie; 309 return t; 310 } 311 312 313 /* Free a packet tag. */ 314 void 315 m_tag_free(struct m_tag *t) 316 { 317 free(t, M_PACKET_TAGS); 318 } 319 320 /* Prepend a packet tag. */ 321 void 322 m_tag_prepend(struct mbuf *m, struct m_tag *t) 323 { 324 KASSERT(m && t, ("m_tag_prepend: null argument, m %p t %p", m, t)); 325 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link); 326 } 327 328 /* Unlink a packet tag. */ 329 void 330 m_tag_unlink(struct mbuf *m, struct m_tag *t) 331 { 332 KASSERT(m && t, ("m_tag_unlink: null argument, m %p t %p", m, t)); 333 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link); 334 } 335 336 /* Unlink and free a packet tag. */ 337 void 338 m_tag_delete(struct mbuf *m, struct m_tag *t) 339 { 340 KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t)); 341 m_tag_unlink(m, t); 342 m_tag_free(t); 343 } 344 345 /* Unlink and free a packet tag chain, starting from given tag. */ 346 void 347 m_tag_delete_chain(struct mbuf *m, struct m_tag *t) 348 { 349 struct m_tag *p, *q; 350 351 KASSERT(m, ("m_tag_delete_chain: null mbuf")); 352 if (t != NULL) 353 p = t; 354 else 355 p = SLIST_FIRST(&m->m_pkthdr.tags); 356 if (p == NULL) 357 return; 358 while ((q = SLIST_NEXT(p, m_tag_link)) != NULL) 359 m_tag_delete(m, q); 360 m_tag_delete(m, p); 361 } 362 363 /* Find a tag, starting from a given position. */ 364 struct m_tag * 365 m_tag_locate(struct mbuf *m, u_int32_t cookie, int type, struct m_tag *t) 366 { 367 struct m_tag *p; 368 369 KASSERT(m, ("m_tag_find: null mbuf")); 370 if (t == NULL) 371 p = SLIST_FIRST(&m->m_pkthdr.tags); 372 else 373 p = SLIST_NEXT(t, m_tag_link); 374 while (p != NULL) { 375 if (p->m_tag_cookie == cookie && p->m_tag_id == type) 376 return p; 377 p = SLIST_NEXT(p, m_tag_link); 378 } 379 return NULL; 380 } 381 382 /* Copy a single tag. */ 383 struct m_tag * 384 m_tag_copy(struct m_tag *t, int how) 385 { 386 struct m_tag *p; 387 388 KASSERT(t, ("m_tag_copy: null tag")); 389 p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how); 390 if (p == NULL) 391 return (NULL); 392 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */ 393 return p; 394 } 395 396 /* 397 * Copy two tag chains. The destination mbuf (to) loses any attached 398 * tags even if the operation fails. This should not be a problem, as 399 * m_tag_copy_chain() is typically called with a newly-allocated 400 * destination mbuf. 401 */ 402 int 403 m_tag_copy_chain(struct mbuf *to, const struct mbuf *from, int how) 404 { 405 struct m_tag *p, *t, *tprev = NULL; 406 407 KASSERT(to && from, 408 ("m_tag_copy: null argument, to %p from %p", to, from)); 409 m_tag_delete_chain(to, NULL); 410 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) { 411 t = m_tag_copy(p, how); 412 if (t == NULL) { 413 m_tag_delete_chain(to, NULL); 414 return 0; 415 } 416 if (tprev == NULL) 417 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link); 418 else { 419 SLIST_INSERT_AFTER(tprev, t, m_tag_link); 420 tprev = t; 421 } 422 } 423 return 1; 424 } 425 426 /* Initialize tags on an mbuf. */ 427 void 428 m_tag_init(struct mbuf *m) 429 { 430 SLIST_INIT(&m->m_pkthdr.tags); 431 } 432 433 /* Get first tag in chain. */ 434 struct m_tag * 435 m_tag_first(struct mbuf *m) 436 { 437 return SLIST_FIRST(&m->m_pkthdr.tags); 438 } 439 440 /* Get next tag in chain. */ 441 struct m_tag * 442 m_tag_next(struct mbuf *m, struct m_tag *t) 443 { 444 return SLIST_NEXT(t, m_tag_link); 445 } 446