1 /* $OpenBSD: uipc_mbuf2.c,v 1.35 2011/11/30 10:26:56 dlg 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/proc.h> 68 #include <sys/malloc.h> 69 #include <sys/mbuf.h> 70 71 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ 72 static struct mbuf *m_dup1(struct mbuf *, int, int, int); 73 74 /* 75 * ensure that [off, off + len] is contiguous on the mbuf chain "m". 76 * packet chain before "off" is kept untouched. 77 * if offp == NULL, the target will start at <retval, 0> on resulting chain. 78 * if offp != NULL, the target will start at <retval, *offp> on resulting chain. 79 * 80 * on error return (NULL return value), original "m" will be freed. 81 * 82 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster) 83 */ 84 struct mbuf * 85 m_pulldown(struct mbuf *m, int off, int len, int *offp) 86 { 87 struct mbuf *n, *o; 88 int hlen, tlen, olen; 89 int sharedcluster; 90 91 /* check invalid arguments. */ 92 if (m == NULL) 93 panic("m == NULL in m_pulldown()"); 94 95 if ((n = m_getptr(m, off, &off)) == NULL) { 96 m_freem(m); 97 return (NULL); /* mbuf chain too short */ 98 } 99 100 sharedcluster = M_READONLY(n); 101 102 /* 103 * the target data is on <n, off>. 104 * if we got enough data on the mbuf "n", we're done. 105 */ 106 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) 107 goto ok; 108 109 /* 110 * when len <= n->m_len - off and off != 0, it is a special case. 111 * len bytes from <n, off> sits in single mbuf, but the caller does 112 * not like the starting position (off). 113 * chop the current mbuf into two pieces, set off to 0. 114 */ 115 if (len <= n->m_len - off) { 116 struct mbuf *mlast; 117 118 o = m_dup1(n, off, n->m_len - off, M_DONTWAIT); 119 if (o == NULL) { 120 m_freem(m); 121 return (NULL); /* ENOBUFS */ 122 } 123 for (mlast = o; mlast->m_next != NULL; mlast = mlast->m_next) 124 ; 125 n->m_len = off; 126 mlast->m_next = n->m_next; 127 n->m_next = o; 128 n = o; 129 off = 0; 130 goto ok; 131 } 132 133 /* 134 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, 135 * and construct contiguous mbuf with m_len == len. 136 * note that hlen + tlen == len, and tlen > 0. 137 */ 138 hlen = n->m_len - off; 139 tlen = len - hlen; 140 141 /* 142 * ensure that we have enough trailing data on mbuf chain. 143 * if not, we can do nothing about the chain. 144 */ 145 olen = 0; 146 for (o = n->m_next; o != NULL; o = o->m_next) 147 olen += o->m_len; 148 if (hlen + olen < len) { 149 m_freem(m); 150 return (NULL); /* mbuf chain too short */ 151 } 152 153 /* 154 * easy cases first. 155 * we need to use m_copydata() to get data from <n->m_next, 0>. 156 */ 157 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen && 158 !sharedcluster) { 159 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); 160 n->m_len += tlen; 161 m_adj(n->m_next, tlen); 162 goto ok; 163 } 164 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen && 165 !sharedcluster && n->m_next->m_len >= tlen) { 166 n->m_next->m_data -= hlen; 167 n->m_next->m_len += hlen; 168 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen); 169 n->m_len -= hlen; 170 n = n->m_next; 171 off = 0; 172 goto ok; 173 } 174 175 /* 176 * now, we need to do the hard way. don't m_copy as there's no room 177 * on both ends. 178 */ 179 if (len > MAXMCLBYTES) { 180 m_freem(m); 181 return (NULL); 182 } 183 MGET(o, M_DONTWAIT, m->m_type); 184 if (o && len > MLEN) { 185 MCLGETI(o, M_DONTWAIT, NULL, len); 186 if ((o->m_flags & M_EXT) == 0) { 187 m_free(o); 188 o = NULL; 189 } 190 } 191 if (!o) { 192 m_freem(m); 193 return (NULL); /* ENOBUFS */ 194 } 195 /* get hlen from <n, off> into <o, 0> */ 196 o->m_len = hlen; 197 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen); 198 n->m_len -= hlen; 199 /* get tlen from <n->m_next, 0> into <o, hlen> */ 200 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); 201 o->m_len += tlen; 202 m_adj(n->m_next, tlen); 203 o->m_next = n->m_next; 204 n->m_next = o; 205 n = o; 206 off = 0; 207 208 ok: 209 if (offp) 210 *offp = off; 211 return (n); 212 } 213 214 static struct mbuf * 215 m_dup1(struct mbuf *m, int off, int len, int wait) 216 { 217 struct mbuf *n; 218 int l; 219 220 if (len > MAXMCLBYTES) 221 return (NULL); 222 if (off == 0 && (m->m_flags & M_PKTHDR) != 0) { 223 MGETHDR(n, wait, m->m_type); 224 if (n == NULL) 225 return (NULL); 226 if (m_dup_pkthdr(n, m, wait)) { 227 m_free(n); 228 return (NULL); 229 } 230 l = MHLEN; 231 } else { 232 MGET(n, wait, m->m_type); 233 l = MLEN; 234 } 235 if (n && len > l) { 236 MCLGETI(n, wait, NULL, len); 237 if ((n->m_flags & M_EXT) == 0) { 238 m_free(n); 239 n = NULL; 240 } 241 } 242 if (!n) 243 return (NULL); 244 245 m_copydata(m, off, len, mtod(n, caddr_t)); 246 n->m_len = len; 247 248 return (n); 249 } 250 251 /* Get a packet tag structure along with specified data following. */ 252 struct m_tag * 253 m_tag_get(int type, int len, int wait) 254 { 255 struct m_tag *t; 256 257 if (len < 0) 258 return (NULL); 259 t = malloc(sizeof(struct m_tag) + len, M_PACKET_TAGS, wait); 260 if (t == NULL) 261 return (NULL); 262 t->m_tag_id = type; 263 t->m_tag_len = len; 264 return (t); 265 } 266 267 /* Prepend a packet tag. */ 268 void 269 m_tag_prepend(struct mbuf *m, struct m_tag *t) 270 { 271 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link); 272 m->m_pkthdr.tagsset |= t->m_tag_id; 273 } 274 275 /* Unlink and free a packet tag. */ 276 void 277 m_tag_delete(struct mbuf *m, struct m_tag *t) 278 { 279 u_int32_t tagsset = 0; 280 struct m_tag *p; 281 282 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link); 283 free(t, M_PACKET_TAGS); 284 285 SLIST_FOREACH(p, &m->m_pkthdr.tags, m_tag_link) 286 tagsset |= p->m_tag_id; 287 m->m_pkthdr.tagsset = tagsset; 288 289 } 290 291 /* Unlink and free a packet tag chain. */ 292 void 293 m_tag_delete_chain(struct mbuf *m) 294 { 295 struct m_tag *p; 296 297 while ((p = SLIST_FIRST(&m->m_pkthdr.tags)) != NULL) { 298 SLIST_REMOVE_HEAD(&m->m_pkthdr.tags, m_tag_link); 299 free(p, M_PACKET_TAGS); 300 } 301 m->m_pkthdr.tagsset = 0; 302 } 303 304 /* Find a tag, starting from a given position. */ 305 struct m_tag * 306 m_tag_find(struct mbuf *m, int type, struct m_tag *t) 307 { 308 struct m_tag *p; 309 310 if (!(m->m_pkthdr.tagsset & type)) 311 return (NULL); 312 313 if (t == NULL) 314 p = SLIST_FIRST(&m->m_pkthdr.tags); 315 else 316 p = SLIST_NEXT(t, m_tag_link); 317 while (p != NULL) { 318 if (p->m_tag_id == type) 319 return (p); 320 p = SLIST_NEXT(p, m_tag_link); 321 } 322 return (NULL); 323 } 324 325 /* Copy a single tag. */ 326 struct m_tag * 327 m_tag_copy(struct m_tag *t, int wait) 328 { 329 struct m_tag *p; 330 331 p = m_tag_get(t->m_tag_id, t->m_tag_len, wait); 332 if (p == NULL) 333 return (NULL); 334 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */ 335 return (p); 336 } 337 338 /* 339 * Copy two tag chains. The destination mbuf (to) loses any attached 340 * tags even if the operation fails. This should not be a problem, as 341 * m_tag_copy_chain() is typically called with a newly-allocated 342 * destination mbuf. 343 */ 344 int 345 m_tag_copy_chain(struct mbuf *to, struct mbuf *from, int wait) 346 { 347 struct m_tag *p, *t, *tprev = NULL; 348 349 m_tag_delete_chain(to); 350 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) { 351 t = m_tag_copy(p, wait); 352 if (t == NULL) { 353 m_tag_delete_chain(to); 354 return (ENOMEM); 355 } 356 if (tprev == NULL) 357 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link); 358 else 359 SLIST_INSERT_AFTER(tprev, t, m_tag_link); 360 tprev = t; 361 to->m_pkthdr.tagsset |= t->m_tag_id; 362 } 363 return (0); 364 } 365 366 /* Initialize tags on an mbuf. */ 367 void 368 m_tag_init(struct mbuf *m) 369 { 370 SLIST_INIT(&m->m_pkthdr.tags); 371 } 372 373 /* Get first tag in chain. */ 374 struct m_tag * 375 m_tag_first(struct mbuf *m) 376 { 377 return (SLIST_FIRST(&m->m_pkthdr.tags)); 378 } 379 380 /* Get next tag in chain. */ 381 struct m_tag * 382 m_tag_next(struct mbuf *m, struct m_tag *t) 383 { 384 return (SLIST_NEXT(t, m_tag_link)); 385 } 386