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 1.15 2007/10/20 10:28:44 sephe 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. Neither the name of the University nor the names of its contributors 48 * may be used to endorse or promote products derived from this software 49 * without specific prior written permission. 50 * 51 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 52 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 53 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 54 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 55 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 56 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 57 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 58 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 59 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 60 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 61 * SUCH DAMAGE. 62 * 63 * @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95 64 */ 65 66 /*#define PULLDOWN_DEBUG*/ 67 68 #include <sys/param.h> 69 #include <sys/systm.h> 70 #include <sys/kernel.h> 71 #include <sys/proc.h> 72 #include <sys/malloc.h> 73 #include <sys/mbuf.h> 74 75 MALLOC_DEFINE(M_PACKET_TAGS, "tag", "packet-attached information"); 76 77 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ 78 static struct mbuf *m_dup1 (struct mbuf *, int, int, int); 79 80 /* 81 * ensure that [off, off + len) is contiguous on the mbuf chain "m". 82 * packet chain before "off" is kept untouched. 83 * if offp == NULL, the target will start at <retval, 0> on resulting chain. 84 * if offp != NULL, the target will start at <retval, *offp> on resulting chain. 85 * 86 * on error return (NULL return value), original "m" will be freed. 87 * 88 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster) 89 */ 90 struct mbuf * 91 m_pulldown(struct mbuf *m, int off, int len, int *offp) 92 { 93 struct mbuf *n, *o; 94 int hlen, tlen, olen; 95 int sharedcluster; 96 97 /* check invalid arguments. */ 98 if (m == NULL) 99 panic("m == NULL in m_pulldown()"); 100 if (len > MCLBYTES) { 101 m_freem(m); 102 return NULL; /* impossible */ 103 } 104 105 #ifdef PULLDOWN_DEBUG 106 { 107 struct mbuf *t; 108 kprintf("before:"); 109 for (t = m; t; t = t->m_next) 110 kprintf(" %d", t->m_len); 111 kprintf("\n"); 112 } 113 #endif 114 n = m; 115 while (n != NULL && off > 0) { 116 if (n->m_len > off) 117 break; 118 off -= n->m_len; 119 n = n->m_next; 120 } 121 /* be sure to point non-empty mbuf */ 122 while (n != NULL && n->m_len == 0) 123 n = n->m_next; 124 if (!n) { 125 m_freem(m); 126 return NULL; /* mbuf chain too short */ 127 } 128 129 sharedcluster = (m_sharecount(n) > 1); 130 131 /* 132 * the target data is on <n, off>. 133 * if we got enough data on the mbuf "n", we're done. 134 */ 135 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) 136 goto ok; 137 138 /* 139 * when len <= n->m_len - off and off != 0, it is a special case. 140 * len bytes from <n, off> sits in single mbuf, but the caller does 141 * not like the starting position (off). 142 * chop the current mbuf into two pieces, set off to 0. 143 */ 144 if (len <= n->m_len - off) { 145 o = m_dup1(n, off, n->m_len - off, MB_DONTWAIT); 146 if (o == NULL) { 147 m_freem(m); 148 return NULL; /* ENOBUFS */ 149 } 150 n->m_len = off; 151 o->m_next = n->m_next; 152 n->m_next = o; 153 n = n->m_next; 154 off = 0; 155 goto ok; 156 } 157 158 /* 159 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, 160 * and construct contiguous mbuf with m_len == len. 161 * note that hlen + tlen == len, and tlen > 0. 162 */ 163 hlen = n->m_len - off; 164 tlen = len - hlen; 165 166 /* 167 * ensure that we have enough trailing data on mbuf chain. 168 * if not, we can do nothing about the chain. 169 */ 170 olen = 0; 171 for (o = n->m_next; o != NULL; o = o->m_next) 172 olen += o->m_len; 173 if (hlen + olen < len) { 174 m_freem(m); 175 return NULL; /* mbuf chain too short */ 176 } 177 178 /* 179 * easy cases first. 180 * we need to use m_copydata() to get data from <n->m_next, 0>. 181 */ 182 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen && 183 !sharedcluster) { 184 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); 185 n->m_len += tlen; 186 m_adj(n->m_next, tlen); 187 goto ok; 188 } 189 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen && 190 !sharedcluster) { 191 n->m_next->m_data -= hlen; 192 n->m_next->m_len += hlen; 193 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen); 194 n->m_len -= hlen; 195 n = n->m_next; 196 off = 0; 197 goto ok; 198 } 199 200 /* 201 * now, we need to do the hard way. don't m_copy as there's no room 202 * on both end. 203 */ 204 o = m_getl(len, MB_DONTWAIT, m->m_type, 0, NULL); 205 if (!o) { 206 m_freem(m); 207 return NULL; /* ENOBUFS */ 208 } 209 /* get hlen from <n, off> into <o, 0> */ 210 o->m_len = hlen; 211 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen); 212 n->m_len -= hlen; 213 /* get tlen from <n->m_next, 0> into <o, hlen> */ 214 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); 215 o->m_len += tlen; 216 m_adj(n->m_next, tlen); 217 o->m_next = n->m_next; 218 n->m_next = o; 219 n = o; 220 off = 0; 221 222 ok: 223 #ifdef PULLDOWN_DEBUG 224 { 225 struct mbuf *t; 226 kprintf("after:"); 227 for (t = m; t; t = t->m_next) 228 kprintf("%c%d", t == n ? '*' : ' ', t->m_len); 229 kprintf(" (off=%d)\n", off); 230 } 231 #endif 232 if (offp) 233 *offp = off; 234 return n; 235 } 236 237 static struct mbuf * 238 m_dup1(struct mbuf *m, int off, int len, int wait) 239 { 240 struct mbuf *n; 241 242 if (len > MCLBYTES) 243 return NULL; 244 n = m_getl(len, wait, m->m_type, m->m_flags, NULL); 245 if (!n) 246 return NULL; 247 if (off == 0 && (m->m_flags & M_PKTHDR) && !m_dup_pkthdr(n, m, wait)) { 248 m_free(n); 249 return NULL; 250 } 251 m_copydata(m, off, len, mtod(n, caddr_t)); 252 return n; 253 } 254 255 /* Get a packet tag structure along with specified data following. */ 256 struct m_tag * 257 m_tag_alloc(uint32_t cookie, int type, int len, int wait) 258 { 259 struct m_tag *t; 260 261 if (len < 0) 262 return NULL; 263 t = kmalloc(len + sizeof(struct m_tag), M_PACKET_TAGS, MBTOM(wait)); 264 if (t == NULL) 265 return NULL; 266 t->m_tag_id = type; 267 t->m_tag_len = len; 268 t->m_tag_cookie = cookie; 269 return t; 270 } 271 272 273 /* Free a packet tag. */ 274 void 275 m_tag_free(struct m_tag *t) 276 { 277 kfree(t, M_PACKET_TAGS); 278 } 279 280 /* Prepend a packet tag. */ 281 void 282 m_tag_prepend(struct mbuf *m, struct m_tag *t) 283 { 284 KASSERT(m && t, ("m_tag_prepend: null argument, m %p t %p", m, t)); 285 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_prepend: mbuf %p non-header", m)); 286 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link); 287 } 288 289 /* Unlink a packet tag. */ 290 void 291 m_tag_unlink(struct mbuf *m, struct m_tag *t) 292 { 293 KASSERT(m && t, ("m_tag_unlink: null argument, m %p t %p", m, t)); 294 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_unlink: mbuf %p non-header", m)); 295 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link); 296 } 297 298 /* Unlink and free a packet tag. */ 299 void 300 m_tag_delete(struct mbuf *m, struct m_tag *t) 301 { 302 KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t)); 303 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_delete: mbuf %p non-header", m)); 304 m_tag_unlink(m, t); 305 m_tag_free(t); 306 } 307 308 /* Unlink and free a packet tag chain, starting from given tag. */ 309 void 310 m_tag_delete_chain(struct mbuf *m) 311 { 312 struct m_tag *p, *q; 313 314 KASSERT(m, ("m_tag_delete_chain: null mbuf")); 315 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_delete_chain: mbuf %p non-header", m)); 316 p = SLIST_FIRST(&m->m_pkthdr.tags); 317 if (p == NULL) 318 return; 319 while ((q = SLIST_NEXT(p, m_tag_link)) != NULL) 320 m_tag_delete(m, q); 321 m_tag_delete(m, p); 322 } 323 324 /* Find a tag, starting from a given position. */ 325 struct m_tag * 326 m_tag_locate(struct mbuf *m, uint32_t cookie, int type, struct m_tag *t) 327 { 328 struct m_tag *p; 329 330 KASSERT(m, ("m_tag_find: null mbuf")); 331 if (t == NULL) 332 p = SLIST_FIRST(&m->m_pkthdr.tags); 333 else 334 p = SLIST_NEXT(t, m_tag_link); 335 while (p != NULL) { 336 if (p->m_tag_cookie == cookie && p->m_tag_id == type) 337 return p; 338 p = SLIST_NEXT(p, m_tag_link); 339 } 340 return NULL; 341 } 342 343 /* Copy a single tag. */ 344 struct m_tag * 345 m_tag_copy(struct m_tag *t, int how) 346 { 347 struct m_tag *p; 348 349 KASSERT(t, ("m_tag_copy: null tag")); 350 p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how); 351 if (p == NULL) 352 return (NULL); 353 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */ 354 return p; 355 } 356 357 /* 358 * Copy two tag chains. The destination mbuf (to) loses any attached 359 * tags even if the operation fails. This should not be a problem, as 360 * m_tag_copy_chain() is typically called with a newly-allocated 361 * destination mbuf. 362 */ 363 int 364 m_tag_copy_chain(struct mbuf *to, const struct mbuf *from, int how) 365 { 366 struct m_tag *p, *t, *tprev = NULL; 367 368 KASSERT(to && from, 369 ("m_tag_copy: null argument, to %p from %p", to, from)); 370 m_tag_delete_chain(to); 371 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) { 372 t = m_tag_copy(p, how); 373 if (t == NULL) { 374 m_tag_delete_chain(to); 375 return 0; 376 } 377 if (tprev == NULL) 378 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link); 379 else { 380 SLIST_INSERT_AFTER(tprev, t, m_tag_link); 381 tprev = t; 382 } 383 } 384 return 1; 385 } 386 387 /* Initialize tags on an mbuf. */ 388 void 389 m_tag_init(struct mbuf *m) 390 { 391 SLIST_INIT(&m->m_pkthdr.tags); 392 } 393 394 /* Get first tag in chain. */ 395 struct m_tag * 396 m_tag_first(struct mbuf *m) 397 { 398 return SLIST_FIRST(&m->m_pkthdr.tags); 399 } 400 401 /* Get next tag in chain. */ 402 struct m_tag * 403 m_tag_next(struct mbuf *m, struct m_tag *t) 404 { 405 return SLIST_NEXT(t, m_tag_link); 406 } 407