1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * IPsec-specific mbuf routines. 33 */ 34 35 #include "opt_ipsec.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/malloc.h> 40 #include <sys/mbuf.h> 41 #include <sys/socket.h> 42 43 #include <net/vnet.h> 44 #include <netinet/in.h> 45 #include <netipsec/ipsec.h> 46 47 /* 48 * Make space for a new header of length hlen at skip bytes 49 * into the packet. When doing this we allocate new mbufs only 50 * when absolutely necessary. The mbuf where the new header 51 * is to go is returned together with an offset into the mbuf. 52 * If NULL is returned then the mbuf chain may have been modified; 53 * the caller is assumed to always free the chain. 54 */ 55 struct mbuf * 56 m_makespace(struct mbuf *m0, int skip, int hlen, int *off) 57 { 58 struct mbuf *m; 59 unsigned remain; 60 61 IPSEC_ASSERT(m0 != NULL, ("null mbuf")); 62 IPSEC_ASSERT(hlen < MHLEN, ("hlen too big: %u", hlen)); 63 64 for (m = m0; m && skip > m->m_len; m = m->m_next) 65 skip -= m->m_len; 66 if (m == NULL) 67 return (NULL); 68 /* 69 * At this point skip is the offset into the mbuf m 70 * where the new header should be placed. Figure out 71 * if there's space to insert the new header. If so, 72 * and copying the remainder makes sense then do so. 73 * Otherwise insert a new mbuf in the chain, splitting 74 * the contents of m as needed. 75 */ 76 remain = m->m_len - skip; /* data to move */ 77 if (remain > skip && 78 hlen + max_linkhdr < M_LEADINGSPACE(m)) { 79 /* 80 * mbuf has enough free space at the beginning. 81 * XXX: which operation is the most heavy - copying of 82 * possible several hundred of bytes or allocation 83 * of new mbuf? We can remove max_linkhdr check 84 * here, but it is possible that this will lead 85 * to allocation of new mbuf in Layer 2 code. 86 */ 87 m->m_data -= hlen; 88 bcopy(mtodo(m, hlen), mtod(m, caddr_t), skip); 89 m->m_len += hlen; 90 *off = skip; 91 } else if (hlen > M_TRAILINGSPACE(m)) { 92 struct mbuf *n0, *n, **np; 93 int todo, len, done, alloc; 94 95 n0 = NULL; 96 np = &n0; 97 alloc = 0; 98 done = 0; 99 todo = remain; 100 while (todo > 0) { 101 if (todo > MHLEN) { 102 n = m_getcl(M_NOWAIT, m->m_type, 0); 103 len = MCLBYTES; 104 } 105 else { 106 n = m_get(M_NOWAIT, m->m_type); 107 len = MHLEN; 108 } 109 if (n == NULL) { 110 m_freem(n0); 111 return NULL; 112 } 113 *np = n; 114 np = &n->m_next; 115 alloc++; 116 len = min(todo, len); 117 memcpy(n->m_data, mtod(m, char *) + skip + done, len); 118 n->m_len = len; 119 done += len; 120 todo -= len; 121 } 122 123 if (hlen <= M_TRAILINGSPACE(m) + remain) { 124 m->m_len = skip + hlen; 125 *off = skip; 126 if (n0 != NULL) { 127 *np = m->m_next; 128 m->m_next = n0; 129 } 130 } 131 else { 132 n = m_get(M_NOWAIT, m->m_type); 133 if (n == NULL) { 134 m_freem(n0); 135 return NULL; 136 } 137 alloc++; 138 139 if ((n->m_next = n0) == NULL) 140 np = &n->m_next; 141 n0 = n; 142 143 *np = m->m_next; 144 m->m_next = n0; 145 146 n->m_len = hlen; 147 m->m_len = skip; 148 149 m = n; /* header is at front ... */ 150 *off = 0; /* ... of new mbuf */ 151 } 152 IPSECSTAT_INC(ips_mbinserted); 153 } else { 154 /* 155 * Copy the remainder to the back of the mbuf 156 * so there's space to write the new header. 157 */ 158 bcopy(mtod(m, caddr_t) + skip, 159 mtod(m, caddr_t) + skip + hlen, remain); 160 m->m_len += hlen; 161 *off = skip; 162 } 163 m0->m_pkthdr.len += hlen; /* adjust packet length */ 164 return m; 165 } 166 167 /* 168 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header 169 * length is updated, and a pointer to the first byte of the padding 170 * (which is guaranteed to be all in one mbuf) is returned. 171 */ 172 caddr_t 173 m_pad(struct mbuf *m, int n) 174 { 175 struct mbuf *m0, *m1; 176 int len, pad; 177 caddr_t retval; 178 179 if (n <= 0) { /* No stupid arguments. */ 180 DPRINTF(("%s: pad length invalid (%d)\n", __func__, n)); 181 m_freem(m); 182 return NULL; 183 } 184 185 len = m->m_pkthdr.len; 186 pad = n; 187 m0 = m; 188 189 while (m0->m_len < len) { 190 len -= m0->m_len; 191 m0 = m0->m_next; 192 } 193 194 if (m0->m_len != len) { 195 DPRINTF(("%s: length mismatch (should be %d instead of %d)\n", 196 __func__, m->m_pkthdr.len, 197 m->m_pkthdr.len + m0->m_len - len)); 198 199 m_freem(m); 200 return NULL; 201 } 202 203 /* Check for zero-length trailing mbufs, and find the last one. */ 204 for (m1 = m0; m1->m_next; m1 = m1->m_next) { 205 if (m1->m_next->m_len != 0) { 206 DPRINTF(("%s: length mismatch (should be %d instead " 207 "of %d)\n", __func__, 208 m->m_pkthdr.len, 209 m->m_pkthdr.len + m1->m_next->m_len)); 210 211 m_freem(m); 212 return NULL; 213 } 214 215 m0 = m1->m_next; 216 } 217 218 if (pad > M_TRAILINGSPACE(m0)) { 219 /* Add an mbuf to the chain. */ 220 MGET(m1, M_NOWAIT, MT_DATA); 221 if (m1 == NULL) { 222 m_freem(m0); 223 DPRINTF(("%s: unable to get extra mbuf\n", __func__)); 224 return NULL; 225 } 226 227 m0->m_next = m1; 228 m0 = m1; 229 m0->m_len = 0; 230 } 231 232 retval = m0->m_data + m0->m_len; 233 m0->m_len += pad; 234 m->m_pkthdr.len += pad; 235 236 return retval; 237 } 238 239 /* 240 * Remove hlen data at offset skip in the packet. This is used by 241 * the protocols strip protocol headers and associated data (e.g. IV, 242 * authenticator) on input. 243 */ 244 int 245 m_striphdr(struct mbuf *m, int skip, int hlen) 246 { 247 struct mbuf *m1; 248 int roff; 249 250 /* Find beginning of header */ 251 m1 = m_getptr(m, skip, &roff); 252 if (m1 == NULL) 253 return (EINVAL); 254 255 /* Remove the header and associated data from the mbuf. */ 256 if (roff == 0) { 257 /* The header was at the beginning of the mbuf */ 258 IPSECSTAT_INC(ips_input_front); 259 m_adj(m1, hlen); 260 if (m1 != m) 261 m->m_pkthdr.len -= hlen; 262 } else if (roff + hlen >= m1->m_len) { 263 struct mbuf *mo; 264 int adjlen; 265 266 /* 267 * Part or all of the header is at the end of this mbuf, 268 * so first let's remove the remainder of the header from 269 * the beginning of the remainder of the mbuf chain, if any. 270 */ 271 IPSECSTAT_INC(ips_input_end); 272 if (roff + hlen > m1->m_len) { 273 adjlen = roff + hlen - m1->m_len; 274 275 /* Adjust the next mbuf by the remainder */ 276 m_adj(m1->m_next, adjlen); 277 278 /* The second mbuf is guaranteed not to have a pkthdr... */ 279 m->m_pkthdr.len -= adjlen; 280 } 281 282 /* Now, let's unlink the mbuf chain for a second...*/ 283 mo = m1->m_next; 284 m1->m_next = NULL; 285 286 /* ...and trim the end of the first part of the chain...sick */ 287 adjlen = m1->m_len - roff; 288 m_adj(m1, -adjlen); 289 if (m1 != m) 290 m->m_pkthdr.len -= adjlen; 291 292 /* Finally, let's relink */ 293 m1->m_next = mo; 294 } else { 295 /* 296 * The header lies in the "middle" of the mbuf; copy 297 * the remainder of the mbuf down over the header. 298 */ 299 IPSECSTAT_INC(ips_input_middle); 300 bcopy(mtod(m1, u_char *) + roff + hlen, 301 mtod(m1, u_char *) + roff, 302 m1->m_len - (roff + hlen)); 303 m1->m_len -= hlen; 304 m->m_pkthdr.len -= hlen; 305 } 306 return (0); 307 } 308 309 /* 310 * Diagnostic routine to check mbuf alignment as required by the 311 * crypto device drivers (that use DMA). 312 */ 313 void 314 m_checkalignment(const char* where, struct mbuf *m0, int off, int len) 315 { 316 int roff; 317 struct mbuf *m = m_getptr(m0, off, &roff); 318 caddr_t addr; 319 320 if (m == NULL) 321 return; 322 printf("%s (off %u len %u): ", where, off, len); 323 addr = mtod(m, caddr_t) + roff; 324 do { 325 int mlen; 326 327 if (((uintptr_t) addr) & 3) { 328 printf("addr misaligned %p,", addr); 329 break; 330 } 331 mlen = m->m_len; 332 if (mlen > len) 333 mlen = len; 334 len -= mlen; 335 if (len && (mlen & 3)) { 336 printf("len mismatch %u,", mlen); 337 break; 338 } 339 m = m->m_next; 340 addr = m ? mtod(m, caddr_t) : NULL; 341 } while (m && len > 0); 342 for (m = m0; m; m = m->m_next) 343 printf(" [%p:%u]", mtod(m, caddr_t), m->m_len); 344 printf("\n"); 345 } 346