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 1.11 2005/06/17 19:12:16 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 MALLOC_DEFINE(M_PACKET_TAGS, "tag", "packet-attached information"); 80 81 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ 82 static struct mbuf *m_dup1 (struct mbuf *, int, int, int); 83 84 /* 85 * ensure that [off, off + len) is contiguous on the mbuf chain "m". 86 * packet chain before "off" is kept untouched. 87 * if offp == NULL, the target will start at <retval, 0> on resulting chain. 88 * if offp != NULL, the target will start at <retval, *offp> on resulting chain. 89 * 90 * on error return (NULL return value), original "m" will be freed. 91 * 92 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster) 93 */ 94 struct mbuf * 95 m_pulldown(m, off, len, offp) 96 struct mbuf *m; 97 int off, len; 98 int *offp; 99 { 100 struct mbuf *n, *o; 101 int hlen, tlen, olen; 102 int sharedcluster; 103 104 /* check invalid arguments. */ 105 if (m == NULL) 106 panic("m == NULL in m_pulldown()"); 107 if (len > MCLBYTES) { 108 m_freem(m); 109 return NULL; /* impossible */ 110 } 111 112 #ifdef PULLDOWN_DEBUG 113 { 114 struct mbuf *t; 115 printf("before:"); 116 for (t = m; t; t = t->m_next) 117 printf(" %d", t->m_len); 118 printf("\n"); 119 } 120 #endif 121 n = m; 122 while (n != NULL && off > 0) { 123 if (n->m_len > off) 124 break; 125 off -= n->m_len; 126 n = n->m_next; 127 } 128 /* be sure to point non-empty mbuf */ 129 while (n != NULL && n->m_len == 0) 130 n = n->m_next; 131 if (!n) { 132 m_freem(m); 133 return NULL; /* mbuf chain too short */ 134 } 135 136 sharedcluster = (m_sharecount(n) > 1); 137 138 /* 139 * the target data is on <n, off>. 140 * if we got enough data on the mbuf "n", we're done. 141 */ 142 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) 143 goto ok; 144 145 /* 146 * when len <= n->m_len - off and off != 0, it is a special case. 147 * len bytes from <n, off> sits in single mbuf, but the caller does 148 * not like the starting position (off). 149 * chop the current mbuf into two pieces, set off to 0. 150 */ 151 if (len <= n->m_len - off) { 152 o = m_dup1(n, off, n->m_len - off, MB_DONTWAIT); 153 if (o == NULL) { 154 m_freem(m); 155 return NULL; /* ENOBUFS */ 156 } 157 n->m_len = off; 158 o->m_next = n->m_next; 159 n->m_next = o; 160 n = n->m_next; 161 off = 0; 162 goto ok; 163 } 164 165 /* 166 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, 167 * and construct contiguous mbuf with m_len == len. 168 * note that hlen + tlen == len, and tlen > 0. 169 */ 170 hlen = n->m_len - off; 171 tlen = len - hlen; 172 173 /* 174 * ensure that we have enough trailing data on mbuf chain. 175 * if not, we can do nothing about the chain. 176 */ 177 olen = 0; 178 for (o = n->m_next; o != NULL; o = o->m_next) 179 olen += o->m_len; 180 if (hlen + olen < len) { 181 m_freem(m); 182 return NULL; /* mbuf chain too short */ 183 } 184 185 /* 186 * easy cases first. 187 * we need to use m_copydata() to get data from <n->m_next, 0>. 188 */ 189 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen && 190 !sharedcluster) { 191 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); 192 n->m_len += tlen; 193 m_adj(n->m_next, tlen); 194 goto ok; 195 } 196 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen && 197 !sharedcluster) { 198 n->m_next->m_data -= hlen; 199 n->m_next->m_len += hlen; 200 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen); 201 n->m_len -= hlen; 202 n = n->m_next; 203 off = 0; 204 goto ok; 205 } 206 207 /* 208 * now, we need to do the hard way. don't m_copy as there's no room 209 * on both end. 210 */ 211 o = m_getl(len, MB_DONTWAIT, m->m_type, 0, NULL); 212 if (!o) { 213 m_freem(m); 214 return NULL; /* ENOBUFS */ 215 } 216 /* get hlen from <n, off> into <o, 0> */ 217 o->m_len = hlen; 218 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen); 219 n->m_len -= hlen; 220 /* get tlen from <n->m_next, 0> into <o, hlen> */ 221 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); 222 o->m_len += tlen; 223 m_adj(n->m_next, tlen); 224 o->m_next = n->m_next; 225 n->m_next = o; 226 n = o; 227 off = 0; 228 229 ok: 230 #ifdef PULLDOWN_DEBUG 231 { 232 struct mbuf *t; 233 printf("after:"); 234 for (t = m; t; t = t->m_next) 235 printf("%c%d", t == n ? '*' : ' ', t->m_len); 236 printf(" (off=%d)\n", off); 237 } 238 #endif 239 if (offp) 240 *offp = off; 241 return n; 242 } 243 244 static struct mbuf * 245 m_dup1(m, off, len, wait) 246 struct mbuf *m; 247 int off; 248 int len; 249 int wait; 250 { 251 struct mbuf *n; 252 253 if (len > MCLBYTES) 254 return NULL; 255 n = m_getl(len, wait, m->m_type, m->m_flags, NULL); 256 if (!n) 257 return NULL; 258 if (off == 0 && (m->m_flags & M_PKTHDR) && !m_dup_pkthdr(n, m, wait)) { 259 m_free(n); 260 return NULL; 261 } 262 m_copydata(m, off, len, mtod(n, caddr_t)); 263 return n; 264 } 265 266 /* Get a packet tag structure along with specified data following. */ 267 struct m_tag * 268 m_tag_alloc(u_int32_t cookie, int type, int len, int wait) 269 { 270 struct m_tag *t; 271 272 if (len < 0) 273 return NULL; 274 t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, 275 wait != MB_WAIT ? M_NOWAIT : M_WAITOK); 276 if (t == NULL) 277 return NULL; 278 t->m_tag_id = type; 279 t->m_tag_len = len; 280 t->m_tag_cookie = cookie; 281 return t; 282 } 283 284 285 /* Free a packet tag. */ 286 void 287 m_tag_free(struct m_tag *t) 288 { 289 free(t, M_PACKET_TAGS); 290 } 291 292 /* Prepend a packet tag. */ 293 void 294 m_tag_prepend(struct mbuf *m, struct m_tag *t) 295 { 296 KASSERT(m && t, ("m_tag_prepend: null argument, m %p t %p", m, t)); 297 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_prepend: mbuf %p non-header", m)); 298 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link); 299 } 300 301 /* Unlink a packet tag. */ 302 void 303 m_tag_unlink(struct mbuf *m, struct m_tag *t) 304 { 305 KASSERT(m && t, ("m_tag_unlink: null argument, m %p t %p", m, t)); 306 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_unlink: mbuf %p non-header", m)); 307 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link); 308 } 309 310 /* Unlink and free a packet tag. */ 311 void 312 m_tag_delete(struct mbuf *m, struct m_tag *t) 313 { 314 KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t)); 315 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_delete: mbuf %p non-header", m)); 316 m_tag_unlink(m, t); 317 m_tag_free(t); 318 } 319 320 /* Unlink and free a packet tag chain, starting from given tag. */ 321 void 322 m_tag_delete_chain(struct mbuf *m) 323 { 324 struct m_tag *p, *q; 325 326 KASSERT(m, ("m_tag_delete_chain: null mbuf")); 327 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_delete_chain: mbuf %p non-header", m)); 328 p = SLIST_FIRST(&m->m_pkthdr.tags); 329 if (p == NULL) 330 return; 331 while ((q = SLIST_NEXT(p, m_tag_link)) != NULL) 332 m_tag_delete(m, q); 333 m_tag_delete(m, p); 334 } 335 336 /* Find a tag, starting from a given position. */ 337 struct m_tag * 338 m_tag_locate(struct mbuf *m, u_int32_t cookie, int type, struct m_tag *t) 339 { 340 struct m_tag *p; 341 342 KASSERT(m, ("m_tag_find: null mbuf")); 343 if (t == NULL) 344 p = SLIST_FIRST(&m->m_pkthdr.tags); 345 else 346 p = SLIST_NEXT(t, m_tag_link); 347 while (p != NULL) { 348 if (p->m_tag_cookie == cookie && p->m_tag_id == type) 349 return p; 350 p = SLIST_NEXT(p, m_tag_link); 351 } 352 return NULL; 353 } 354 355 /* Copy a single tag. */ 356 struct m_tag * 357 m_tag_copy(struct m_tag *t, int how) 358 { 359 struct m_tag *p; 360 361 KASSERT(t, ("m_tag_copy: null tag")); 362 p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how); 363 if (p == NULL) 364 return (NULL); 365 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */ 366 return p; 367 } 368 369 /* 370 * Copy two tag chains. The destination mbuf (to) loses any attached 371 * tags even if the operation fails. This should not be a problem, as 372 * m_tag_copy_chain() is typically called with a newly-allocated 373 * destination mbuf. 374 */ 375 int 376 m_tag_copy_chain(struct mbuf *to, const struct mbuf *from, int how) 377 { 378 struct m_tag *p, *t, *tprev = NULL; 379 380 KASSERT(to && from, 381 ("m_tag_copy: null argument, to %p from %p", to, from)); 382 m_tag_delete_chain(to); 383 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) { 384 t = m_tag_copy(p, how); 385 if (t == NULL) { 386 m_tag_delete_chain(to); 387 return 0; 388 } 389 if (tprev == NULL) 390 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link); 391 else { 392 SLIST_INSERT_AFTER(tprev, t, m_tag_link); 393 tprev = t; 394 } 395 } 396 return 1; 397 } 398 399 /* Initialize tags on an mbuf. */ 400 void 401 m_tag_init(struct mbuf *m) 402 { 403 SLIST_INIT(&m->m_pkthdr.tags); 404 } 405 406 /* Get first tag in chain. */ 407 struct m_tag * 408 m_tag_first(struct mbuf *m) 409 { 410 return SLIST_FIRST(&m->m_pkthdr.tags); 411 } 412 413 /* Get next tag in chain. */ 414 struct m_tag * 415 m_tag_next(struct mbuf *m, struct m_tag *t) 416 { 417 return SLIST_NEXT(t, m_tag_link); 418 } 419