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; 94 95 n0 = NULL; 96 np = &n0; 97 done = 0; 98 todo = remain; 99 while (todo > 0) { 100 if (todo > MHLEN) { 101 n = m_getcl(M_NOWAIT, m->m_type, 0); 102 len = MCLBYTES; 103 } 104 else { 105 n = m_get(M_NOWAIT, m->m_type); 106 len = MHLEN; 107 } 108 if (n == NULL) { 109 m_freem(n0); 110 return NULL; 111 } 112 *np = n; 113 np = &n->m_next; 114 len = min(todo, len); 115 memcpy(n->m_data, mtod(m, char *) + skip + done, len); 116 n->m_len = len; 117 done += len; 118 todo -= len; 119 } 120 121 if (hlen <= M_TRAILINGSPACE(m) + remain) { 122 m->m_len = skip + hlen; 123 *off = skip; 124 if (n0 != NULL) { 125 *np = m->m_next; 126 m->m_next = n0; 127 } 128 } 129 else { 130 n = m_get(M_NOWAIT, m->m_type); 131 if (n == NULL) { 132 m_freem(n0); 133 return NULL; 134 } 135 136 if ((n->m_next = n0) == NULL) 137 np = &n->m_next; 138 n0 = n; 139 140 *np = m->m_next; 141 m->m_next = n0; 142 143 n->m_len = hlen; 144 m->m_len = skip; 145 146 m = n; /* header is at front ... */ 147 *off = 0; /* ... of new mbuf */ 148 } 149 IPSECSTAT_INC(ips_mbinserted); 150 } else { 151 /* 152 * Copy the remainder to the back of the mbuf 153 * so there's space to write the new header. 154 */ 155 bcopy(mtod(m, caddr_t) + skip, 156 mtod(m, caddr_t) + skip + hlen, remain); 157 m->m_len += hlen; 158 *off = skip; 159 } 160 m0->m_pkthdr.len += hlen; /* adjust packet length */ 161 return m; 162 } 163 164 /* 165 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header 166 * length is updated, and a pointer to the first byte of the padding 167 * (which is guaranteed to be all in one mbuf) is returned. 168 */ 169 caddr_t 170 m_pad(struct mbuf *m, int n) 171 { 172 struct mbuf *m0, *m1; 173 int len, pad; 174 caddr_t retval; 175 176 if (n <= 0) { /* No stupid arguments. */ 177 DPRINTF(("%s: pad length invalid (%d)\n", __func__, n)); 178 m_freem(m); 179 return NULL; 180 } 181 182 len = m->m_pkthdr.len; 183 pad = n; 184 m0 = m; 185 186 while (m0->m_len < len) { 187 len -= m0->m_len; 188 m0 = m0->m_next; 189 } 190 191 if (m0->m_len != len) { 192 DPRINTF(("%s: length mismatch (should be %d instead of %d)\n", 193 __func__, m->m_pkthdr.len, 194 m->m_pkthdr.len + m0->m_len - len)); 195 196 m_freem(m); 197 return NULL; 198 } 199 200 /* Check for zero-length trailing mbufs, and find the last one. */ 201 for (m1 = m0; m1->m_next; m1 = m1->m_next) { 202 if (m1->m_next->m_len != 0) { 203 DPRINTF(("%s: length mismatch (should be %d instead " 204 "of %d)\n", __func__, 205 m->m_pkthdr.len, 206 m->m_pkthdr.len + m1->m_next->m_len)); 207 208 m_freem(m); 209 return NULL; 210 } 211 212 m0 = m1->m_next; 213 } 214 215 if (pad > M_TRAILINGSPACE(m0)) { 216 /* Add an mbuf to the chain. */ 217 MGET(m1, M_NOWAIT, MT_DATA); 218 if (m1 == NULL) { 219 m_freem(m0); 220 DPRINTF(("%s: unable to get extra mbuf\n", __func__)); 221 return NULL; 222 } 223 224 m0->m_next = m1; 225 m0 = m1; 226 m0->m_len = 0; 227 } 228 229 retval = m0->m_data + m0->m_len; 230 m0->m_len += pad; 231 m->m_pkthdr.len += pad; 232 233 return retval; 234 } 235 236 /* 237 * Remove hlen data at offset skip in the packet. This is used by 238 * the protocols strip protocol headers and associated data (e.g. IV, 239 * authenticator) on input. 240 */ 241 int 242 m_striphdr(struct mbuf *m, int skip, int hlen) 243 { 244 struct mbuf *m1; 245 int roff; 246 247 /* Find beginning of header */ 248 m1 = m_getptr(m, skip, &roff); 249 if (m1 == NULL) 250 return (EINVAL); 251 252 /* Remove the header and associated data from the mbuf. */ 253 if (roff == 0) { 254 /* The header was at the beginning of the mbuf */ 255 IPSECSTAT_INC(ips_input_front); 256 m_adj(m1, hlen); 257 if (m1 != m) 258 m->m_pkthdr.len -= hlen; 259 } else if (roff + hlen >= m1->m_len) { 260 struct mbuf *mo; 261 int adjlen; 262 263 /* 264 * Part or all of the header is at the end of this mbuf, 265 * so first let's remove the remainder of the header from 266 * the beginning of the remainder of the mbuf chain, if any. 267 */ 268 IPSECSTAT_INC(ips_input_end); 269 if (roff + hlen > m1->m_len) { 270 adjlen = roff + hlen - m1->m_len; 271 272 /* Adjust the next mbuf by the remainder */ 273 m_adj(m1->m_next, adjlen); 274 275 /* The second mbuf is guaranteed not to have a pkthdr... */ 276 m->m_pkthdr.len -= adjlen; 277 } 278 279 /* Now, let's unlink the mbuf chain for a second...*/ 280 mo = m1->m_next; 281 m1->m_next = NULL; 282 283 /* ...and trim the end of the first part of the chain...sick */ 284 adjlen = m1->m_len - roff; 285 m_adj(m1, -adjlen); 286 if (m1 != m) 287 m->m_pkthdr.len -= adjlen; 288 289 /* Finally, let's relink */ 290 m1->m_next = mo; 291 } else { 292 /* 293 * The header lies in the "middle" of the mbuf; copy 294 * the remainder of the mbuf down over the header. 295 */ 296 IPSECSTAT_INC(ips_input_middle); 297 bcopy(mtod(m1, u_char *) + roff + hlen, 298 mtod(m1, u_char *) + roff, 299 m1->m_len - (roff + hlen)); 300 m1->m_len -= hlen; 301 m->m_pkthdr.len -= hlen; 302 } 303 return (0); 304 } 305 306 /* 307 * Diagnostic routine to check mbuf alignment as required by the 308 * crypto device drivers (that use DMA). 309 */ 310 void 311 m_checkalignment(const char* where, struct mbuf *m0, int off, int len) 312 { 313 int roff; 314 struct mbuf *m = m_getptr(m0, off, &roff); 315 caddr_t addr; 316 317 if (m == NULL) 318 return; 319 printf("%s (off %u len %u): ", where, off, len); 320 addr = mtod(m, caddr_t) + roff; 321 do { 322 int mlen; 323 324 if (((uintptr_t) addr) & 3) { 325 printf("addr misaligned %p,", addr); 326 break; 327 } 328 mlen = m->m_len; 329 if (mlen > len) 330 mlen = len; 331 len -= mlen; 332 if (len && (mlen & 3)) { 333 printf("len mismatch %u,", mlen); 334 break; 335 } 336 m = m->m_next; 337 addr = m ? mtod(m, caddr_t) : NULL; 338 } while (m && len > 0); 339 for (m = m0; m; m = m->m_next) 340 printf(" [%p:%u]", mtod(m, caddr_t), m->m_len); 341 printf("\n"); 342 } 343