1 /* $OpenBSD: uipc_mbuf2.c,v 1.29 2008/11/30 18:22:15 deraadt 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 if (len > MCLBYTES) { 95 m_freem(m); 96 return (NULL); /* impossible */ 97 } 98 99 n = m; 100 while (n != NULL && off > 0) { 101 if (n->m_len > off) 102 break; 103 off -= n->m_len; 104 n = n->m_next; 105 } 106 /* be sure to point non-empty mbuf */ 107 while (n != NULL && n->m_len == 0) 108 n = n->m_next; 109 if (!n) { 110 m_freem(m); 111 return (NULL); /* mbuf chain too short */ 112 } 113 114 sharedcluster = M_READONLY(n); 115 116 /* 117 * the target data is on <n, off>. 118 * if we got enough data on the mbuf "n", we're done. 119 */ 120 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) 121 goto ok; 122 123 /* 124 * when len <= n->m_len - off and off != 0, it is a special case. 125 * len bytes from <n, off> sits in single mbuf, but the caller does 126 * not like the starting position (off). 127 * chop the current mbuf into two pieces, set off to 0. 128 */ 129 if (len <= n->m_len - off) { 130 struct mbuf *mlast; 131 132 o = m_dup1(n, off, n->m_len - off, M_DONTWAIT); 133 if (o == NULL) { 134 m_freem(m); 135 return (NULL); /* ENOBUFS */ 136 } 137 for (mlast = o; mlast->m_next != NULL; mlast = mlast->m_next) 138 ; 139 n->m_len = off; 140 mlast->m_next = n->m_next; 141 n->m_next = o; 142 n = o; 143 off = 0; 144 goto ok; 145 } 146 147 /* 148 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, 149 * and construct contiguous mbuf with m_len == len. 150 * note that hlen + tlen == len, and tlen > 0. 151 */ 152 hlen = n->m_len - off; 153 tlen = len - hlen; 154 155 /* 156 * ensure that we have enough trailing data on mbuf chain. 157 * if not, we can do nothing about the chain. 158 */ 159 olen = 0; 160 for (o = n->m_next; o != NULL; o = o->m_next) 161 olen += o->m_len; 162 if (hlen + olen < len) { 163 m_freem(m); 164 return (NULL); /* mbuf chain too short */ 165 } 166 167 /* 168 * easy cases first. 169 * we need to use m_copydata() to get data from <n->m_next, 0>. 170 */ 171 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen && 172 !sharedcluster) { 173 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); 174 n->m_len += tlen; 175 m_adj(n->m_next, tlen); 176 goto ok; 177 } 178 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen && 179 !sharedcluster && n->m_next->m_len >= tlen) { 180 n->m_next->m_data -= hlen; 181 n->m_next->m_len += hlen; 182 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen); 183 n->m_len -= hlen; 184 n = n->m_next; 185 off = 0; 186 goto ok; 187 } 188 189 /* 190 * now, we need to do the hard way. don't m_copy as there's no room 191 * on both ends. 192 */ 193 MGET(o, M_DONTWAIT, m->m_type); 194 if (o && len > MLEN) { 195 MCLGET(o, M_DONTWAIT); 196 if ((o->m_flags & M_EXT) == 0) { 197 m_free(o); 198 o = NULL; 199 } 200 } 201 if (!o) { 202 m_freem(m); 203 return (NULL); /* ENOBUFS */ 204 } 205 /* get hlen from <n, off> into <o, 0> */ 206 o->m_len = hlen; 207 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen); 208 n->m_len -= hlen; 209 /* get tlen from <n->m_next, 0> into <o, hlen> */ 210 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); 211 o->m_len += tlen; 212 m_adj(n->m_next, tlen); 213 o->m_next = n->m_next; 214 n->m_next = o; 215 n = o; 216 off = 0; 217 218 ok: 219 if (offp) 220 *offp = off; 221 return (n); 222 } 223 224 static struct mbuf * 225 m_dup1(struct mbuf *m, int off, int len, int wait) 226 { 227 struct mbuf *n; 228 int l; 229 230 if (len > MCLBYTES) 231 return (NULL); 232 if (off == 0 && (m->m_flags & M_PKTHDR) != 0) { 233 MGETHDR(n, wait, m->m_type); 234 if (n == NULL) 235 return (NULL); 236 M_DUP_PKTHDR(n, m); 237 l = MHLEN; 238 } else { 239 MGET(n, wait, m->m_type); 240 l = MLEN; 241 } 242 if (n && len > l) { 243 MCLGET(n, wait); 244 if ((n->m_flags & M_EXT) == 0) { 245 m_free(n); 246 n = NULL; 247 } 248 } 249 if (!n) 250 return (NULL); 251 252 m_copydata(m, off, len, mtod(n, caddr_t)); 253 n->m_len = len; 254 255 return (n); 256 } 257 258 /* Get a packet tag structure along with specified data following. */ 259 struct m_tag * 260 m_tag_get(int type, int len, int wait) 261 { 262 struct m_tag *t; 263 264 if (len < 0) 265 return (NULL); 266 t = malloc(sizeof(struct m_tag) + len, M_PACKET_TAGS, wait); 267 if (t == NULL) 268 return (NULL); 269 t->m_tag_id = type; 270 t->m_tag_len = len; 271 return (t); 272 } 273 274 /* Prepend a packet tag. */ 275 void 276 m_tag_prepend(struct mbuf *m, struct m_tag *t) 277 { 278 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link); 279 } 280 281 /* Unlink and free a packet tag. */ 282 void 283 m_tag_delete(struct mbuf *m, struct m_tag *t) 284 { 285 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link); 286 free(t, M_PACKET_TAGS); 287 } 288 289 /* Unlink and free a packet tag chain. */ 290 void 291 m_tag_delete_chain(struct mbuf *m) 292 { 293 struct m_tag *p; 294 295 while ((p = SLIST_FIRST(&m->m_pkthdr.tags)) != NULL) { 296 SLIST_REMOVE_HEAD(&m->m_pkthdr.tags, m_tag_link); 297 free(p, M_PACKET_TAGS); 298 } 299 } 300 301 /* Find a tag, starting from a given position. */ 302 struct m_tag * 303 m_tag_find(struct mbuf *m, int type, struct m_tag *t) 304 { 305 struct m_tag *p; 306 307 if (t == NULL) 308 p = SLIST_FIRST(&m->m_pkthdr.tags); 309 else 310 p = SLIST_NEXT(t, m_tag_link); 311 while (p != NULL) { 312 if (p->m_tag_id == type) 313 return (p); 314 p = SLIST_NEXT(p, m_tag_link); 315 } 316 return (NULL); 317 } 318 319 /* Copy a single tag. */ 320 struct m_tag * 321 m_tag_copy(struct m_tag *t) 322 { 323 struct m_tag *p; 324 325 p = m_tag_get(t->m_tag_id, t->m_tag_len, M_NOWAIT); 326 if (p == NULL) 327 return (NULL); 328 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */ 329 return (p); 330 } 331 332 /* 333 * Copy two tag chains. The destination mbuf (to) loses any attached 334 * tags even if the operation fails. This should not be a problem, as 335 * m_tag_copy_chain() is typically called with a newly-allocated 336 * destination mbuf. 337 */ 338 int 339 m_tag_copy_chain(struct mbuf *to, struct mbuf *from) 340 { 341 struct m_tag *p, *t, *tprev = NULL; 342 343 m_tag_delete_chain(to); 344 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) { 345 t = m_tag_copy(p); 346 if (t == NULL) { 347 m_tag_delete_chain(to); 348 return (0); 349 } 350 if (tprev == NULL) 351 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link); 352 else 353 SLIST_INSERT_AFTER(tprev, t, m_tag_link); 354 tprev = t; 355 } 356 return (1); 357 } 358 359 /* Initialize tags on an mbuf. */ 360 void 361 m_tag_init(struct mbuf *m) 362 { 363 SLIST_INIT(&m->m_pkthdr.tags); 364 } 365 366 /* Get first tag in chain. */ 367 struct m_tag * 368 m_tag_first(struct mbuf *m) 369 { 370 return (SLIST_FIRST(&m->m_pkthdr.tags)); 371 } 372 373 /* Get next tag in chain. */ 374 struct m_tag * 375 m_tag_next(struct mbuf *m, struct m_tag *t) 376 { 377 return (SLIST_NEXT(t, m_tag_link)); 378 } 379