1 /* $NetBSD: ipsec_mbuf.c,v 1.16 2017/05/19 04:34:09 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 1.16 2017/05/19 04:34:09 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 <net/net_osdep.h> 50 51 /* 52 * Create a writable copy of the mbuf chain. While doing this 53 * we compact the chain with a goal of producing a chain with 54 * at most two mbufs. The second mbuf in this chain is likely 55 * to be a cluster. The primary purpose of this work is to create 56 * a writable packet for encryption, compression, etc. The 57 * secondary goal is to linearize the data so the data can be 58 * passed to crypto hardware in the most efficient manner possible. 59 */ 60 struct mbuf * 61 m_clone(struct mbuf *m0) 62 { 63 struct mbuf *m, *mprev; 64 struct mbuf *n, *mfirst, *mlast; 65 int len, off; 66 67 KASSERT(m0 != NULL); 68 69 mprev = NULL; 70 for (m = m0; m != NULL; m = mprev->m_next) { 71 /* 72 * Regular mbufs are ignored unless there's a cluster 73 * in front of it that we can use to coalesce. We do 74 * the latter mainly so later clusters can be coalesced 75 * also w/o having to handle them specially (i.e. convert 76 * mbuf+cluster -> cluster). This optimization is heavily 77 * influenced by the assumption that we're running over 78 * Ethernet where MCLBYTES is large enough that the max 79 * packet size will permit lots of coalescing into a 80 * single cluster. This in turn permits efficient 81 * crypto operations, especially when using hardware. 82 */ 83 if ((m->m_flags & M_EXT) == 0) { 84 if (mprev && (mprev->m_flags & M_EXT) && 85 m->m_len <= M_TRAILINGSPACE(mprev)) { 86 /* XXX: this ignores mbuf types */ 87 memcpy(mtod(mprev, char *) + mprev->m_len, 88 mtod(m, char *), m->m_len); 89 mprev->m_len += m->m_len; 90 mprev->m_next = m->m_next; /* unlink from chain */ 91 m_free(m); /* reclaim mbuf */ 92 IPSEC_STATINC(IPSEC_STAT_MBCOALESCED); 93 } else { 94 mprev = m; 95 } 96 continue; 97 } 98 /* 99 * Writable mbufs are left alone (for now). Note 100 * that for 4.x systems it's not possible to identify 101 * whether or not mbufs with external buffers are 102 * writable unless they use clusters. 103 */ 104 if (M_EXT_WRITABLE(m)) { 105 mprev = m; 106 continue; 107 } 108 109 /* 110 * Not writable, replace with a copy or coalesce with 111 * the previous mbuf if possible (since we have to copy 112 * it anyway, we try to reduce the number of mbufs and 113 * clusters so that future work is easier). 114 */ 115 KASSERTMSG(m->m_flags & M_EXT, "m_flags 0x%x", m->m_flags); 116 /* NB: we only coalesce into a cluster or larger */ 117 if (mprev != NULL && (mprev->m_flags & M_EXT) && 118 m->m_len <= M_TRAILINGSPACE(mprev)) { 119 /* XXX: this ignores mbuf types */ 120 memcpy(mtod(mprev, char *) + mprev->m_len, 121 mtod(m, char *), m->m_len); 122 mprev->m_len += m->m_len; 123 mprev->m_next = m->m_next; /* unlink from chain */ 124 m_free(m); /* reclaim mbuf */ 125 IPSEC_STATINC(IPSEC_STAT_CLCOALESCED); 126 continue; 127 } 128 129 /* 130 * Allocate new space to hold the copy... 131 */ 132 /* XXX why can M_PKTHDR be set past the first mbuf? */ 133 if (mprev == NULL && (m->m_flags & M_PKTHDR)) { 134 /* 135 * NB: if a packet header is present we must 136 * allocate the mbuf separately from any cluster 137 * because M_MOVE_PKTHDR will smash the data 138 * pointer and drop the M_EXT marker. 139 */ 140 MGETHDR(n, M_DONTWAIT, m->m_type); 141 if (n == NULL) { 142 m_freem(m0); 143 return (NULL); 144 } 145 M_MOVE_PKTHDR(n, m); 146 MCLGET(n, M_DONTWAIT); 147 if ((n->m_flags & M_EXT) == 0) { 148 m_free(n); 149 m_freem(m0); 150 return (NULL); 151 } 152 } else { 153 n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags); 154 if (n == NULL) { 155 m_freem(m0); 156 return (NULL); 157 } 158 } 159 /* 160 * ... and copy the data. We deal with jumbo mbufs 161 * (i.e. m_len > MCLBYTES) by splitting them into 162 * clusters. We could just malloc a buffer and make 163 * it external but too many device drivers don't know 164 * how to break up the non-contiguous memory when 165 * doing DMA. 166 */ 167 len = m->m_len; 168 off = 0; 169 mfirst = n; 170 mlast = NULL; 171 for (;;) { 172 int cc = min(len, MCLBYTES); 173 memcpy(mtod(n, char *), mtod(m, char *) + off, cc); 174 n->m_len = cc; 175 if (mlast != NULL) 176 mlast->m_next = n; 177 mlast = n; 178 IPSEC_STATINC(IPSEC_STAT_CLCOPIED); 179 180 len -= cc; 181 if (len <= 0) 182 break; 183 off += cc; 184 185 n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags); 186 if (n == NULL) { 187 m_freem(mfirst); 188 m_freem(m0); 189 return (NULL); 190 } 191 } 192 n->m_next = m->m_next; 193 if (mprev == NULL) 194 m0 = mfirst; /* new head of chain */ 195 else 196 mprev->m_next = mfirst; /* replace old mbuf */ 197 m_free(m); /* release old mbuf */ 198 mprev = mfirst; 199 } 200 return (m0); 201 } 202 203 /* 204 * Make space for a new header of length hlen at skip bytes 205 * into the packet. When doing this we allocate new mbufs only 206 * when absolutely necessary. The mbuf where the new header 207 * is to go is returned together with an offset into the mbuf. 208 * If NULL is returned then the mbuf chain may have been modified; 209 * the caller is assumed to always free the chain. 210 */ 211 struct mbuf * 212 m_makespace(struct mbuf *m0, int skip, int hlen, int *off) 213 { 214 struct mbuf *m; 215 unsigned remain; 216 217 KASSERT(m0 != NULL); 218 KASSERTMSG(hlen < MHLEN, "hlen too big: %u", hlen); 219 220 for (m = m0; m && skip > m->m_len; m = m->m_next) 221 skip -= m->m_len; 222 if (m == NULL) 223 return (NULL); 224 /* 225 * At this point skip is the offset into the mbuf m 226 * where the new header should be placed. Figure out 227 * if there's space to insert the new header. If so, 228 * and copying the remainder makese sense then do so. 229 * Otherwise insert a new mbuf in the chain, splitting 230 * the contents of m as needed. 231 */ 232 remain = m->m_len - skip; /* data to move */ 233 if (hlen > M_TRAILINGSPACE(m)) { 234 struct mbuf *n0, *n, **np; 235 int todo, len, done, alloc; 236 237 n0 = NULL; 238 np = &n0; 239 alloc = 0; 240 done = 0; 241 todo = remain; 242 while (todo > 0) { 243 if (todo > MHLEN) { 244 n = m_getcl(M_DONTWAIT, m->m_type, 0); 245 len = MCLBYTES; 246 } 247 else { 248 n = m_get(M_DONTWAIT, m->m_type); 249 len = MHLEN; 250 } 251 if (n == NULL) { 252 m_freem(n0); 253 return NULL; 254 } 255 *np = n; 256 np = &n->m_next; 257 alloc++; 258 len = min(todo, len); 259 memcpy(n->m_data, mtod(m, char *) + skip + done, len); 260 n->m_len = len; 261 done += len; 262 todo -= len; 263 } 264 265 if (hlen <= M_TRAILINGSPACE(m) + remain) { 266 m->m_len = skip + hlen; 267 *off = skip; 268 if (n0 != NULL) { 269 *np = m->m_next; 270 m->m_next = n0; 271 } 272 } 273 else { 274 n = m_get(M_DONTWAIT, m->m_type); 275 if (n == NULL) { 276 m_freem(n0); 277 return NULL; 278 } 279 alloc++; 280 281 if ((n->m_next = n0) == NULL) 282 np = &n->m_next; 283 n0 = n; 284 285 *np = m->m_next; 286 m->m_next = n0; 287 288 n->m_len = hlen; 289 m->m_len = skip; 290 291 m = n; /* header is at front ... */ 292 *off = 0; /* ... of new mbuf */ 293 } 294 295 IPSEC_STATADD(IPSEC_STAT_MBINSERTED, alloc); 296 } else { 297 /* 298 * Copy the remainder to the back of the mbuf 299 * so there's space to write the new header. 300 */ 301 /* XXX can this be memcpy? does it handle overlap? */ 302 ovbcopy(mtod(m, char *) + skip, 303 mtod(m, char *) + skip + hlen, remain); 304 m->m_len += hlen; 305 *off = skip; 306 } 307 m0->m_pkthdr.len += hlen; /* adjust packet length */ 308 return m; 309 } 310 311 /* 312 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header 313 * length is updated, and a pointer to the first byte of the padding 314 * (which is guaranteed to be all in one mbuf) is returned. 315 */ 316 void * 317 m_pad(struct mbuf *m, int n) 318 { 319 register struct mbuf *m0, *m1; 320 register int len, pad; 321 void *retval; 322 323 if (n <= 0) { /* No stupid arguments. */ 324 IPSECLOG(LOG_DEBUG, "pad length invalid (%d)\n", n); 325 m_freem(m); 326 return NULL; 327 } 328 329 len = m->m_pkthdr.len; 330 pad = n; 331 m0 = m; 332 333 while (m0->m_len < len) { 334 KASSERTMSG(m0->m_next != NULL, 335 "m0 null, len %u m_len %u", len, m0->m_len);/*XXX*/ 336 len -= m0->m_len; 337 m0 = m0->m_next; 338 } 339 340 if (m0->m_len != len) { 341 IPSECLOG(LOG_DEBUG, 342 "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 IPSECLOG(LOG_DEBUG, 353 "length mismatch (should be %d 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 IPSECLOG(LOG_DEBUG, "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 */ 390 int 391 m_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 */ 455 void 456 m_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