1 /* $FreeBSD: src/sys/kern/uipc_mbuf2.c,v 1.2.2.5 2003/01/23 21:06:44 sam Exp $ */ 2 /* $KAME: uipc_mbuf2.c,v 1.31 2001/11/28 11:08:53 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 /*#define PULLDOWN_DEBUG*/ 66 67 #include <sys/param.h> 68 #include <sys/systm.h> 69 #include <sys/kernel.h> 70 #include <sys/proc.h> 71 #include <sys/malloc.h> 72 #include <sys/mbuf.h> 73 74 MALLOC_DEFINE(M_PACKET_TAGS, "tag", "packet-attached information"); 75 76 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ 77 static struct mbuf *m_dup1 (struct mbuf *, int, int, int); 78 79 /* 80 * ensure that [off, off + len) is contiguous on the mbuf chain "m". 81 * packet chain before "off" is kept untouched. 82 * if offp == NULL, the target will start at <retval, 0> on resulting chain. 83 * if offp != NULL, the target will start at <retval, *offp> on resulting chain. 84 * 85 * on error return (NULL return value), original "m" will be freed. 86 * 87 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster) 88 */ 89 struct mbuf * 90 m_pulldown(struct mbuf *m, int off, int len, int *offp) 91 { 92 struct mbuf *n, *o; 93 int hlen, tlen, olen; 94 int sharedcluster; 95 96 /* check invalid arguments. */ 97 if (m == NULL) 98 panic("m == NULL in m_pulldown()"); 99 if (len > MCLBYTES) { 100 m_freem(m); 101 return NULL; /* impossible */ 102 } 103 104 #ifdef PULLDOWN_DEBUG 105 { 106 struct mbuf *t; 107 kprintf("before:"); 108 for (t = m; t; t = t->m_next) 109 kprintf(" %d", t->m_len); 110 kprintf("\n"); 111 } 112 #endif 113 n = m; 114 while (n != NULL && off > 0) { 115 if (n->m_len > off) 116 break; 117 off -= n->m_len; 118 n = n->m_next; 119 } 120 /* be sure to point non-empty mbuf */ 121 while (n != NULL && n->m_len == 0) 122 n = n->m_next; 123 if (!n) { 124 m_freem(m); 125 return NULL; /* mbuf chain too short */ 126 } 127 128 sharedcluster = (m_sharecount(n) > 1); 129 130 /* 131 * the target data is on <n, off>. 132 * if we got enough data on the mbuf "n", we're done. 133 */ 134 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) 135 goto ok; 136 137 /* 138 * when len <= n->m_len - off and off != 0, it is a special case. 139 * len bytes from <n, off> sits in single mbuf, but the caller does 140 * not like the starting position (off). 141 * chop the current mbuf into two pieces, set off to 0. 142 */ 143 if (len <= n->m_len - off) { 144 o = m_dup1(n, off, n->m_len - off, M_NOWAIT); 145 if (o == NULL) { 146 m_freem(m); 147 return NULL; /* ENOBUFS */ 148 } 149 n->m_len = off; 150 o->m_next = n->m_next; 151 n->m_next = o; 152 n = n->m_next; 153 off = 0; 154 goto ok; 155 } 156 157 /* 158 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, 159 * and construct contiguous mbuf with m_len == len. 160 * note that hlen + tlen == len, and tlen > 0. 161 */ 162 hlen = n->m_len - off; 163 tlen = len - hlen; 164 165 /* 166 * ensure that we have enough trailing data on mbuf chain. 167 * if not, we can do nothing about the chain. 168 */ 169 olen = 0; 170 for (o = n->m_next; o != NULL; o = o->m_next) 171 olen += o->m_len; 172 if (hlen + olen < len) { 173 m_freem(m); 174 return NULL; /* mbuf chain too short */ 175 } 176 177 /* 178 * easy cases first. 179 * we need to use m_copydata() to get data from <n->m_next, 0>. 180 */ 181 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen && 182 !sharedcluster) { 183 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); 184 n->m_len += tlen; 185 m_adj(n->m_next, tlen); 186 goto ok; 187 } 188 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen && 189 !sharedcluster && n->m_next->m_len >= tlen) { 190 n->m_next->m_data -= hlen; 191 n->m_next->m_len += hlen; 192 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen); 193 n->m_len -= hlen; 194 n = n->m_next; 195 off = 0; 196 goto ok; 197 } 198 199 /* 200 * now, we need to do the hard way. don't m_copym as there's no room 201 * on both end. 202 */ 203 o = m_getl(len, M_NOWAIT, m->m_type, 0, NULL); 204 if (!o) { 205 m_freem(m); 206 return NULL; /* ENOBUFS */ 207 } 208 /* get hlen from <n, off> into <o, 0> */ 209 o->m_len = hlen; 210 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen); 211 n->m_len -= hlen; 212 /* get tlen from <n->m_next, 0> into <o, hlen> */ 213 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); 214 o->m_len += tlen; 215 m_adj(n->m_next, tlen); 216 o->m_next = n->m_next; 217 n->m_next = o; 218 n = o; 219 off = 0; 220 221 ok: 222 #ifdef PULLDOWN_DEBUG 223 { 224 struct mbuf *t; 225 kprintf("after:"); 226 for (t = m; t; t = t->m_next) 227 kprintf("%c%d", t == n ? '*' : ' ', t->m_len); 228 kprintf(" (off=%d)\n", off); 229 } 230 #endif 231 if (offp) 232 *offp = off; 233 return n; 234 } 235 236 static struct mbuf * 237 m_dup1(struct mbuf *m, int off, int len, int wait) 238 { 239 struct mbuf *n; 240 241 if (len > MCLBYTES) 242 return NULL; 243 n = m_getl(len, wait, m->m_type, m->m_flags, NULL); 244 if (!n) 245 return NULL; 246 if (off == 0 && (m->m_flags & M_PKTHDR) && !m_dup_pkthdr(n, m, wait)) { 247 m_free(n); 248 return NULL; 249 } 250 m_copydata(m, off, len, mtod(n, void *)); 251 return n; 252 } 253 254 /* Get a packet tag structure along with specified data following. */ 255 struct m_tag * 256 m_tag_alloc(uint32_t cookie, int type, int len, int mflags) 257 { 258 struct m_tag *t; 259 260 if (len < 0) 261 return NULL; 262 t = kmalloc(len + sizeof(struct m_tag), M_PACKET_TAGS, mflags); 263 if (t == NULL) 264 return NULL; 265 t->m_tag_id = type; 266 t->m_tag_len = len; 267 t->m_tag_cookie = cookie; 268 return t; 269 } 270 271 272 /* Free a packet tag. */ 273 void 274 m_tag_free(struct m_tag *t) 275 { 276 kfree(t, M_PACKET_TAGS); 277 } 278 279 /* Prepend a packet tag. */ 280 void 281 m_tag_prepend(struct mbuf *m, struct m_tag *t) 282 { 283 KASSERT(m && t, ("m_tag_prepend: null argument, m %p t %p", m, t)); 284 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_prepend: mbuf %p non-header", m)); 285 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link); 286 } 287 288 /* Unlink a packet tag. */ 289 void 290 m_tag_unlink(struct mbuf *m, struct m_tag *t) 291 { 292 KASSERT(m && t, ("m_tag_unlink: null argument, m %p t %p", m, t)); 293 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_unlink: mbuf %p non-header", m)); 294 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link); 295 } 296 297 /* Unlink and free a packet tag. */ 298 void 299 m_tag_delete(struct mbuf *m, struct m_tag *t) 300 { 301 KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t)); 302 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_delete: mbuf %p non-header", m)); 303 m_tag_unlink(m, t); 304 m_tag_free(t); 305 } 306 307 /* Unlink and free a packet tag chain, starting from given tag. */ 308 void 309 m_tag_delete_chain(struct mbuf *m) 310 { 311 struct m_tag *p, *q; 312 313 KASSERT(m, ("m_tag_delete_chain: null mbuf")); 314 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_delete_chain: mbuf %p non-header", m)); 315 p = SLIST_FIRST(&m->m_pkthdr.tags); 316 if (p == NULL) 317 return; 318 while ((q = SLIST_NEXT(p, m_tag_link)) != NULL) 319 m_tag_delete(m, q); 320 m_tag_delete(m, p); 321 } 322 323 /* Find a tag, starting from a given position. */ 324 struct m_tag * 325 m_tag_locate(struct mbuf *m, uint32_t cookie, int type, struct m_tag *t) 326 { 327 struct m_tag *p; 328 329 KASSERT(m, ("m_tag_find: null mbuf")); 330 if (t == NULL) 331 p = SLIST_FIRST(&m->m_pkthdr.tags); 332 else 333 p = SLIST_NEXT(t, m_tag_link); 334 while (p != NULL) { 335 if (p->m_tag_cookie == cookie && p->m_tag_id == type) 336 return p; 337 p = SLIST_NEXT(p, m_tag_link); 338 } 339 return NULL; 340 } 341 342 /* Copy a single tag. */ 343 struct m_tag * 344 m_tag_copy(struct m_tag *t, int how) 345 { 346 struct m_tag *p; 347 348 KASSERT(t, ("m_tag_copy: null tag")); 349 p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how); 350 if (p == NULL) 351 return (NULL); 352 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */ 353 return p; 354 } 355 356 /* 357 * Copy two tag chains. The destination mbuf (to) loses any attached 358 * tags even if the operation fails. This should not be a problem, as 359 * m_tag_copy_chain() is typically called with a newly-allocated 360 * destination mbuf. 361 */ 362 int 363 m_tag_copy_chain(struct mbuf *to, const struct mbuf *from, int how) 364 { 365 struct m_tag *p, *t, *tprev = NULL; 366 367 KASSERT(to && from, 368 ("m_tag_copy: null argument, to %p from %p", to, from)); 369 m_tag_delete_chain(to); 370 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) { 371 t = m_tag_copy(p, how); 372 if (t == NULL) { 373 m_tag_delete_chain(to); 374 return 0; 375 } 376 if (tprev == NULL) 377 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link); 378 else { 379 SLIST_INSERT_AFTER(tprev, t, m_tag_link); 380 tprev = t; 381 } 382 } 383 return 1; 384 } 385 386 /* Initialize tags on an mbuf. */ 387 void 388 m_tag_init(struct mbuf *m) 389 { 390 SLIST_INIT(&m->m_pkthdr.tags); 391 } 392 393 /* Get first tag in chain. */ 394 struct m_tag * 395 m_tag_first(struct mbuf *m) 396 { 397 return SLIST_FIRST(&m->m_pkthdr.tags); 398 } 399 400 /* Get next tag in chain. */ 401 struct m_tag * 402 m_tag_next(struct mbuf *m, struct m_tag *t) 403 { 404 return SLIST_NEXT(t, m_tag_link); 405 } 406