ipsec_mbuf.c revision 1.14
1/* $NetBSD: ipsec_mbuf.c,v 1.14 2017/04/18 05:26:42 ozaki-r Exp $ */ 2/*- 3 * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD: /repoman/r/ncvs/src/sys/netipsec/ipsec_mbuf.c,v 1.5.2.2 2003/03/28 20:32:53 sam Exp $ 28 */ 29 30#include <sys/cdefs.h> 31__KERNEL_RCSID(0, "$NetBSD: ipsec_mbuf.c,v 1.14 2017/04/18 05:26:42 ozaki-r Exp $"); 32 33/* 34 * IPsec-specific mbuf routines. 35 */ 36 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/mbuf.h> 40#include <sys/socket.h> 41 42#include <net/route.h> 43#include <netinet/in.h> 44 45#include <netipsec/ipsec.h> 46#include <netipsec/ipsec_var.h> 47#include <netipsec/ipsec_private.h> 48 49#include <netipsec/ipsec_osdep.h> 50#include <net/net_osdep.h> 51 52/* 53 * Create a writable copy of the mbuf chain. While doing this 54 * we compact the chain with a goal of producing a chain with 55 * at most two mbufs. The second mbuf in this chain is likely 56 * to be a cluster. The primary purpose of this work is to create 57 * a writable packet for encryption, compression, etc. The 58 * secondary goal is to linearize the data so the data can be 59 * passed to crypto hardware in the most efficient manner possible. 60 */ 61struct mbuf * 62m_clone(struct mbuf *m0) 63{ 64 struct mbuf *m, *mprev; 65 struct mbuf *n, *mfirst, *mlast; 66 int len, off; 67 68 KASSERT(m0 != NULL); 69 70 mprev = NULL; 71 for (m = m0; m != NULL; m = mprev->m_next) { 72 /* 73 * Regular mbufs are ignored unless there's a cluster 74 * in front of it that we can use to coalesce. We do 75 * the latter mainly so later clusters can be coalesced 76 * also w/o having to handle them specially (i.e. convert 77 * mbuf+cluster -> cluster). This optimization is heavily 78 * influenced by the assumption that we're running over 79 * Ethernet where MCLBYTES is large enough that the max 80 * packet size will permit lots of coalescing into a 81 * single cluster. This in turn permits efficient 82 * crypto operations, especially when using hardware. 83 */ 84 if ((m->m_flags & M_EXT) == 0) { 85 if (mprev && (mprev->m_flags & M_EXT) && 86 m->m_len <= M_TRAILINGSPACE(mprev)) { 87 /* XXX: this ignores mbuf types */ 88 memcpy(mtod(mprev, char *) + mprev->m_len, 89 mtod(m, char *), m->m_len); 90 mprev->m_len += m->m_len; 91 mprev->m_next = m->m_next; /* unlink from chain */ 92 m_free(m); /* reclaim mbuf */ 93 IPSEC_STATINC(IPSEC_STAT_MBCOALESCED); 94 } else { 95 mprev = m; 96 } 97 continue; 98 } 99 /* 100 * Writable mbufs are left alone (for now). Note 101 * that for 4.x systems it's not possible to identify 102 * whether or not mbufs with external buffers are 103 * writable unless they use clusters. 104 */ 105 if (M_EXT_WRITABLE(m)) { 106 mprev = m; 107 continue; 108 } 109 110 /* 111 * Not writable, replace with a copy or coalesce with 112 * the previous mbuf if possible (since we have to copy 113 * it anyway, we try to reduce the number of mbufs and 114 * clusters so that future work is easier). 115 */ 116 KASSERTMSG(m->m_flags & M_EXT, "m_flags 0x%x", m->m_flags); 117 /* NB: we only coalesce into a cluster or larger */ 118 if (mprev != NULL && (mprev->m_flags & M_EXT) && 119 m->m_len <= M_TRAILINGSPACE(mprev)) { 120 /* XXX: this ignores mbuf types */ 121 memcpy(mtod(mprev, char *) + mprev->m_len, 122 mtod(m, char *), m->m_len); 123 mprev->m_len += m->m_len; 124 mprev->m_next = m->m_next; /* unlink from chain */ 125 m_free(m); /* reclaim mbuf */ 126 IPSEC_STATINC(IPSEC_STAT_CLCOALESCED); 127 continue; 128 } 129 130 /* 131 * Allocate new space to hold the copy... 132 */ 133 /* XXX why can M_PKTHDR be set past the first mbuf? */ 134 if (mprev == NULL && (m->m_flags & M_PKTHDR)) { 135 /* 136 * NB: if a packet header is present we must 137 * allocate the mbuf separately from any cluster 138 * because M_MOVE_PKTHDR will smash the data 139 * pointer and drop the M_EXT marker. 140 */ 141 MGETHDR(n, M_DONTWAIT, m->m_type); 142 if (n == NULL) { 143 m_freem(m0); 144 return (NULL); 145 } 146 M_MOVE_PKTHDR(n, m); 147 MCLGET(n, M_DONTWAIT); 148 if ((n->m_flags & M_EXT) == 0) { 149 m_free(n); 150 m_freem(m0); 151 return (NULL); 152 } 153 } else { 154 n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags); 155 if (n == NULL) { 156 m_freem(m0); 157 return (NULL); 158 } 159 } 160 /* 161 * ... and copy the data. We deal with jumbo mbufs 162 * (i.e. m_len > MCLBYTES) by splitting them into 163 * clusters. We could just malloc a buffer and make 164 * it external but too many device drivers don't know 165 * how to break up the non-contiguous memory when 166 * doing DMA. 167 */ 168 len = m->m_len; 169 off = 0; 170 mfirst = n; 171 mlast = NULL; 172 for (;;) { 173 int cc = min(len, MCLBYTES); 174 memcpy(mtod(n, char *), mtod(m, char *) + off, cc); 175 n->m_len = cc; 176 if (mlast != NULL) 177 mlast->m_next = n; 178 mlast = n; 179 IPSEC_STATINC(IPSEC_STAT_CLCOPIED); 180 181 len -= cc; 182 if (len <= 0) 183 break; 184 off += cc; 185 186 n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags); 187 if (n == NULL) { 188 m_freem(mfirst); 189 m_freem(m0); 190 return (NULL); 191 } 192 } 193 n->m_next = m->m_next; 194 if (mprev == NULL) 195 m0 = mfirst; /* new head of chain */ 196 else 197 mprev->m_next = mfirst; /* replace old mbuf */ 198 m_free(m); /* release old mbuf */ 199 mprev = mfirst; 200 } 201 return (m0); 202} 203 204/* 205 * Make space for a new header of length hlen at skip bytes 206 * into the packet. When doing this we allocate new mbufs only 207 * when absolutely necessary. The mbuf where the new header 208 * is to go is returned together with an offset into the mbuf. 209 * If NULL is returned then the mbuf chain may have been modified; 210 * the caller is assumed to always free the chain. 211 */ 212struct mbuf * 213m_makespace(struct mbuf *m0, int skip, int hlen, int *off) 214{ 215 struct mbuf *m; 216 unsigned remain; 217 218 KASSERT(m0 != NULL); 219 KASSERTMSG(hlen < MHLEN, "hlen too big: %u", hlen); 220 221 for (m = m0; m && skip > m->m_len; m = m->m_next) 222 skip -= m->m_len; 223 if (m == NULL) 224 return (NULL); 225 /* 226 * At this point skip is the offset into the mbuf m 227 * where the new header should be placed. Figure out 228 * if there's space to insert the new header. If so, 229 * and copying the remainder makese sense then do so. 230 * Otherwise insert a new mbuf in the chain, splitting 231 * the contents of m as needed. 232 */ 233 remain = m->m_len - skip; /* data to move */ 234 if (hlen > M_TRAILINGSPACE(m)) { 235 struct mbuf *n0, *n, **np; 236 int todo, len, done, alloc; 237 238 n0 = NULL; 239 np = &n0; 240 alloc = 0; 241 done = 0; 242 todo = remain; 243 while (todo > 0) { 244 if (todo > MHLEN) { 245 n = m_getcl(M_DONTWAIT, m->m_type, 0); 246 len = MCLBYTES; 247 } 248 else { 249 n = m_get(M_DONTWAIT, m->m_type); 250 len = MHLEN; 251 } 252 if (n == NULL) { 253 m_freem(n0); 254 return NULL; 255 } 256 *np = n; 257 np = &n->m_next; 258 alloc++; 259 len = min(todo, len); 260 memcpy(n->m_data, mtod(m, char *) + skip + done, len); 261 n->m_len = len; 262 done += len; 263 todo -= len; 264 } 265 266 if (hlen <= M_TRAILINGSPACE(m) + remain) { 267 m->m_len = skip + hlen; 268 *off = skip; 269 if (n0 != NULL) { 270 *np = m->m_next; 271 m->m_next = n0; 272 } 273 } 274 else { 275 n = m_get(M_DONTWAIT, m->m_type); 276 if (n == NULL) { 277 m_freem(n0); 278 return NULL; 279 } 280 alloc++; 281 282 if ((n->m_next = n0) == NULL) 283 np = &n->m_next; 284 n0 = n; 285 286 *np = m->m_next; 287 m->m_next = n0; 288 289 n->m_len = hlen; 290 m->m_len = skip; 291 292 m = n; /* header is at front ... */ 293 *off = 0; /* ... of new mbuf */ 294 } 295 296 IPSEC_STATADD(IPSEC_STAT_MBINSERTED, alloc); 297 } else { 298 /* 299 * Copy the remainder to the back of the mbuf 300 * so there's space to write the new header. 301 */ 302 /* XXX can this be memcpy? does it handle overlap? */ 303 ovbcopy(mtod(m, char *) + skip, 304 mtod(m, char *) + skip + hlen, remain); 305 m->m_len += hlen; 306 *off = skip; 307 } 308 m0->m_pkthdr.len += hlen; /* adjust packet length */ 309 return m; 310} 311 312/* 313 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header 314 * length is updated, and a pointer to the first byte of the padding 315 * (which is guaranteed to be all in one mbuf) is returned. 316 */ 317void * 318m_pad(struct mbuf *m, int n) 319{ 320 register struct mbuf *m0, *m1; 321 register int len, pad; 322 void *retval; 323 324 if (n <= 0) { /* No stupid arguments. */ 325 DPRINTF(("m_pad: pad length invalid (%d)\n", n)); 326 m_freem(m); 327 return NULL; 328 } 329 330 len = m->m_pkthdr.len; 331 pad = n; 332 m0 = m; 333 334 while (m0->m_len < len) { 335 KASSERTMSG(m0->m_next != NULL, 336 "m0 null, len %u m_len %u", len, m0->m_len);/*XXX*/ 337 len -= m0->m_len; 338 m0 = m0->m_next; 339 } 340 341 if (m0->m_len != len) { 342 DPRINTF(("m_pad: length mismatch (should be %d instead of %d)\n", 343 m->m_pkthdr.len, m->m_pkthdr.len + m0->m_len - len)); 344 345 m_freem(m); 346 return NULL; 347 } 348 349 /* Check for zero-length trailing mbufs, and find the last one. */ 350 for (m1 = m0; m1->m_next; m1 = m1->m_next) { 351 if (m1->m_next->m_len != 0) { 352 DPRINTF(("m_pad: length mismatch (should be %d " 353 "instead of %d)\n", 354 m->m_pkthdr.len, 355 m->m_pkthdr.len + m1->m_next->m_len)); 356 357 m_freem(m); 358 return NULL; 359 } 360 361 m0 = m1->m_next; 362 } 363 364 if (pad > M_TRAILINGSPACE(m0)) { 365 /* Add an mbuf to the chain. */ 366 MGET(m1, M_DONTWAIT, MT_DATA); 367 if (m1 == 0) { 368 m_freem(m0); 369 DPRINTF(("m_pad: unable to get extra mbuf\n")); 370 return NULL; 371 } 372 373 m0->m_next = m1; 374 m0 = m1; 375 m0->m_len = 0; 376 } 377 378 retval = m0->m_data + m0->m_len; 379 m0->m_len += pad; 380 m->m_pkthdr.len += pad; 381 382 return retval; 383} 384 385/* 386 * Remove hlen data at offset skip in the packet. This is used by 387 * the protocols strip protocol headers and associated data (e.g. IV, 388 * authenticator) on input. 389 */ 390int 391m_striphdr(struct mbuf *m, int skip, int hlen) 392{ 393 struct mbuf *m1; 394 int roff; 395 396 /* Find beginning of header */ 397 m1 = m_getptr(m, skip, &roff); 398 if (m1 == NULL) 399 return (EINVAL); 400 401 /* Remove the header and associated data from the mbuf. */ 402 if (roff == 0) { 403 /* The header was at the beginning of the mbuf */ 404 IPSEC_STATINC(IPSEC_STAT_INPUT_FRONT); 405 m_adj(m1, hlen); 406 if ((m1->m_flags & M_PKTHDR) == 0) 407 m->m_pkthdr.len -= hlen; 408 } else if (roff + hlen >= m1->m_len) { 409 struct mbuf *mo; 410 411 /* 412 * Part or all of the header is at the end of this mbuf, 413 * so first let's remove the remainder of the header from 414 * the beginning of the remainder of the mbuf chain, if any. 415 */ 416 IPSEC_STATINC(IPSEC_STAT_INPUT_END); 417 if (roff + hlen > m1->m_len) { 418 /* Adjust the next mbuf by the remainder */ 419 m_adj(m1->m_next, roff + hlen - m1->m_len); 420 421 /* The second mbuf is guaranteed not to have a pkthdr... */ 422 m->m_pkthdr.len -= (roff + hlen - m1->m_len); 423 } 424 425 /* Now, let's unlink the mbuf chain for a second...*/ 426 mo = m1->m_next; 427 m1->m_next = NULL; 428 429 /* ...and trim the end of the first part of the chain...sick */ 430 m_adj(m1, -(m1->m_len - roff)); 431 if ((m1->m_flags & M_PKTHDR) == 0) 432 m->m_pkthdr.len -= (m1->m_len - roff); 433 434 /* Finally, let's relink */ 435 m1->m_next = mo; 436 } else { 437 /* 438 * The header lies in the "middle" of the mbuf; copy 439 * the remainder of the mbuf down over the header. 440 */ 441 IPSEC_STATINC(IPSEC_STAT_INPUT_MIDDLE); 442 ovbcopy(mtod(m1, u_char *) + roff + hlen, 443 mtod(m1, u_char *) + roff, 444 m1->m_len - (roff + hlen)); 445 m1->m_len -= hlen; 446 m->m_pkthdr.len -= hlen; 447 } 448 return (0); 449} 450 451/* 452 * Diagnostic routine to check mbuf alignment as required by the 453 * crypto device drivers (that use DMA). 454 */ 455void 456m_checkalignment(const char* where, struct mbuf *m0, int off, int len) 457{ 458 int roff; 459 struct mbuf *m = m_getptr(m0, off, &roff); 460 void *addr; 461 462 if (m == NULL) 463 return; 464 printf("%s (off %u len %u): ", where, off, len); 465 addr = mtod(m, char *) + roff; 466 do { 467 int mlen; 468 469 if (((uintptr_t) addr) & 3) { 470 printf("addr misaligned %p,", addr); 471 break; 472 } 473 mlen = m->m_len; 474 if (mlen > len) 475 mlen = len; 476 len -= mlen; 477 if (len && (mlen & 3)) { 478 printf("len mismatch %u,", mlen); 479 break; 480 } 481 m = m->m_next; 482 addr = m ? mtod(m, void *) : NULL; 483 } while (m && len > 0); 484 for (m = m0; m; m = m->m_next) 485 printf(" [%p:%u]", mtod(m, void *), m->m_len); 486 printf("\n"); 487} 488