1 /* $OpenBSD: uipc_mbuf2.c,v 1.45 2020/12/12 11:48:54 jan 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/malloc.h> 68 #include <sys/pool.h> 69 #include <sys/mbuf.h> 70 71 extern struct pool mtagpool; 72 73 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ 74 static struct mbuf *m_dup1(struct mbuf *, int, int, int); 75 76 /* 77 * ensure that [off, off + len] is contiguous on the mbuf chain "m". 78 * packet chain before "off" is kept untouched. 79 * if offp == NULL, the target will start at <retval, 0> on resulting chain. 80 * if offp != NULL, the target will start at <retval, *offp> on resulting chain. 81 * 82 * on error return (NULL return value), original "m" will be freed. 83 * 84 * XXX m_trailingspace/m_leadingspace on shared cluster (sharedcluster) 85 */ 86 struct mbuf * 87 m_pulldown(struct mbuf *m, int off, int len, int *offp) 88 { 89 struct mbuf *n, *o; 90 int hlen, tlen, olen; 91 int sharedcluster; 92 93 /* check invalid arguments. */ 94 if (m == NULL) 95 panic("m == NULL in m_pulldown()"); 96 97 if ((n = m_getptr(m, off, &off)) == NULL) { 98 m_freem(m); 99 return (NULL); /* mbuf chain too short */ 100 } 101 102 sharedcluster = M_READONLY(n); 103 104 /* 105 * the target data is on <n, off>. 106 * if we got enough data on the mbuf "n", we're done. 107 */ 108 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) 109 goto ok; 110 111 /* 112 * when len <= n->m_len - off and off != 0, it is a special case. 113 * len bytes from <n, off> sits in single mbuf, but the caller does 114 * not like the starting position (off). 115 * chop the current mbuf into two pieces, set off to 0. 116 */ 117 if (len <= n->m_len - off) { 118 struct mbuf *mlast; 119 120 o = m_dup1(n, off, n->m_len - off, M_DONTWAIT); 121 if (o == NULL) { 122 m_freem(m); 123 return (NULL); /* ENOBUFS */ 124 } 125 for (mlast = o; mlast->m_next != NULL; mlast = mlast->m_next) 126 ; 127 n->m_len = off; 128 mlast->m_next = n->m_next; 129 n->m_next = o; 130 n = o; 131 off = 0; 132 goto ok; 133 } 134 135 /* 136 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, 137 * and construct contiguous mbuf with m_len == len. 138 * note that hlen + tlen == len, and tlen > 0. 139 */ 140 hlen = n->m_len - off; 141 tlen = len - hlen; 142 143 /* 144 * ensure that we have enough trailing data on mbuf chain. 145 * if not, we can do nothing about the chain. 146 */ 147 olen = 0; 148 for (o = n->m_next; o != NULL; o = o->m_next) 149 olen += o->m_len; 150 if (hlen + olen < len) { 151 m_freem(m); 152 return (NULL); /* mbuf chain too short */ 153 } 154 155 /* 156 * easy cases first. 157 * we need to use m_copydata() to get data from <n->m_next, 0>. 158 */ 159 if ((off == 0 || offp) && m_trailingspace(n) >= tlen && 160 !sharedcluster) { 161 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); 162 n->m_len += tlen; 163 m_adj(n->m_next, tlen); 164 goto ok; 165 } 166 if ((off == 0 || offp) && m_leadingspace(n->m_next) >= hlen && 167 !sharedcluster && n->m_next->m_len >= tlen) { 168 n->m_next->m_data -= hlen; 169 n->m_next->m_len += hlen; 170 memmove(mtod(n->m_next, caddr_t), mtod(n, caddr_t) + off, hlen); 171 n->m_len -= hlen; 172 n = n->m_next; 173 off = 0; 174 goto ok; 175 } 176 177 /* 178 * now, we need to do the hard way. don't m_copym as there's no room 179 * on both ends. 180 */ 181 if (len > MAXMCLBYTES) { 182 m_freem(m); 183 return (NULL); 184 } 185 MGET(o, M_DONTWAIT, m->m_type); 186 if (o && len > MLEN) { 187 MCLGETL(o, M_DONTWAIT, len); 188 if ((o->m_flags & M_EXT) == 0) { 189 m_free(o); 190 o = NULL; 191 } 192 } 193 if (!o) { 194 m_freem(m); 195 return (NULL); /* ENOBUFS */ 196 } 197 /* get hlen from <n, off> into <o, 0> */ 198 o->m_len = hlen; 199 memmove(mtod(o, caddr_t), mtod(n, caddr_t) + off, hlen); 200 n->m_len -= hlen; 201 /* get tlen from <n->m_next, 0> into <o, hlen> */ 202 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); 203 o->m_len += tlen; 204 m_adj(n->m_next, tlen); 205 o->m_next = n->m_next; 206 n->m_next = o; 207 n = o; 208 off = 0; 209 210 ok: 211 if (offp) 212 *offp = off; 213 return (n); 214 } 215 216 static struct mbuf * 217 m_dup1(struct mbuf *m, int off, int len, int wait) 218 { 219 struct mbuf *n; 220 int l; 221 222 if (len > MAXMCLBYTES) 223 return (NULL); 224 if (off == 0 && (m->m_flags & M_PKTHDR) != 0) { 225 MGETHDR(n, wait, m->m_type); 226 if (n == NULL) 227 return (NULL); 228 if (m_dup_pkthdr(n, m, wait)) { 229 m_free(n); 230 return (NULL); 231 } 232 l = MHLEN; 233 } else { 234 MGET(n, wait, m->m_type); 235 l = MLEN; 236 } 237 if (n && len > l) { 238 MCLGETL(n, wait, len); 239 if ((n->m_flags & M_EXT) == 0) { 240 m_free(n); 241 n = NULL; 242 } 243 } 244 if (!n) 245 return (NULL); 246 247 m_copydata(m, off, len, mtod(n, caddr_t)); 248 n->m_len = len; 249 250 return (n); 251 } 252 253 /* Get a packet tag structure along with specified data following. */ 254 struct m_tag * 255 m_tag_get(int type, int len, int wait) 256 { 257 struct m_tag *t; 258 259 if (len < 0) 260 return (NULL); 261 if (len > PACKET_TAG_MAXSIZE) 262 panic("requested tag size for pool %#x is too big", type); 263 t = pool_get(&mtagpool, wait == M_WAITOK ? PR_WAITOK : PR_NOWAIT); 264 if (t == NULL) 265 return (NULL); 266 t->m_tag_id = type; 267 t->m_tag_len = len; 268 return (t); 269 } 270 271 /* Prepend a packet tag. */ 272 void 273 m_tag_prepend(struct mbuf *m, struct m_tag *t) 274 { 275 SLIST_INSERT_HEAD(&m->m_pkthdr.ph_tags, t, m_tag_link); 276 m->m_pkthdr.ph_tagsset |= t->m_tag_id; 277 } 278 279 /* Unlink and free a packet tag. */ 280 void 281 m_tag_delete(struct mbuf *m, struct m_tag *t) 282 { 283 u_int32_t ph_tagsset = 0; 284 struct m_tag *p; 285 286 SLIST_REMOVE(&m->m_pkthdr.ph_tags, t, m_tag, m_tag_link); 287 pool_put(&mtagpool, t); 288 289 SLIST_FOREACH(p, &m->m_pkthdr.ph_tags, m_tag_link) 290 ph_tagsset |= p->m_tag_id; 291 m->m_pkthdr.ph_tagsset = ph_tagsset; 292 293 } 294 295 /* Unlink and free a packet tag chain. */ 296 void 297 m_tag_delete_chain(struct mbuf *m) 298 { 299 struct m_tag *p; 300 301 while ((p = SLIST_FIRST(&m->m_pkthdr.ph_tags)) != NULL) { 302 SLIST_REMOVE_HEAD(&m->m_pkthdr.ph_tags, m_tag_link); 303 pool_put(&mtagpool, p); 304 } 305 m->m_pkthdr.ph_tagsset = 0; 306 } 307 308 /* Find a tag, starting from a given position. */ 309 struct m_tag * 310 m_tag_find(struct mbuf *m, int type, struct m_tag *t) 311 { 312 struct m_tag *p; 313 314 if (!(m->m_pkthdr.ph_tagsset & type)) 315 return (NULL); 316 317 if (t == NULL) 318 p = SLIST_FIRST(&m->m_pkthdr.ph_tags); 319 else 320 p = SLIST_NEXT(t, m_tag_link); 321 while (p != NULL) { 322 if (p->m_tag_id == type) 323 return (p); 324 p = SLIST_NEXT(p, m_tag_link); 325 } 326 return (NULL); 327 } 328 329 /* Copy a single tag. */ 330 struct m_tag * 331 m_tag_copy(struct m_tag *t, int wait) 332 { 333 struct m_tag *p; 334 335 p = m_tag_get(t->m_tag_id, t->m_tag_len, wait); 336 if (p == NULL) 337 return (NULL); 338 memcpy(p + 1, t + 1, t->m_tag_len); /* Copy the data */ 339 return (p); 340 } 341 342 /* 343 * Copy two tag chains. The destination mbuf (to) loses any attached 344 * tags even if the operation fails. This should not be a problem, as 345 * m_tag_copy_chain() is typically called with a newly-allocated 346 * destination mbuf. 347 */ 348 int 349 m_tag_copy_chain(struct mbuf *to, struct mbuf *from, int wait) 350 { 351 struct m_tag *p, *t, *tprev = NULL; 352 353 m_tag_delete_chain(to); 354 SLIST_FOREACH(p, &from->m_pkthdr.ph_tags, m_tag_link) { 355 t = m_tag_copy(p, wait); 356 if (t == NULL) { 357 m_tag_delete_chain(to); 358 return (ENOBUFS); 359 } 360 if (tprev == NULL) 361 SLIST_INSERT_HEAD(&to->m_pkthdr.ph_tags, t, m_tag_link); 362 else 363 SLIST_INSERT_AFTER(tprev, t, m_tag_link); 364 tprev = t; 365 to->m_pkthdr.ph_tagsset |= t->m_tag_id; 366 } 367 return (0); 368 } 369 370 /* Initialize tags on an mbuf. */ 371 void 372 m_tag_init(struct mbuf *m) 373 { 374 SLIST_INIT(&m->m_pkthdr.ph_tags); 375 } 376 377 /* Get first tag in chain. */ 378 struct m_tag * 379 m_tag_first(struct mbuf *m) 380 { 381 return (SLIST_FIRST(&m->m_pkthdr.ph_tags)); 382 } 383 384 /* Get next tag in chain. */ 385 struct m_tag * 386 m_tag_next(struct mbuf *m, struct m_tag *t) 387 { 388 return (SLIST_NEXT(t, m_tag_link)); 389 } 390