1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 29 /* 30 * IPsec-specific mbuf routines. 31 */ 32 33 #include "opt_ipsec.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/malloc.h> 38 #include <sys/mbuf.h> 39 #include <sys/socket.h> 40 41 #include <net/vnet.h> 42 #include <netinet/in.h> 43 #include <netipsec/ipsec.h> 44 45 /* 46 * Make space for a new header of length hlen at skip bytes 47 * into the packet. When doing this we allocate new mbufs only 48 * when absolutely necessary. The mbuf where the new header 49 * is to go is returned together with an offset into the mbuf. 50 * If NULL is returned then the mbuf chain may have been modified; 51 * the caller is assumed to always free the chain. 52 */ 53 struct mbuf * 54 m_makespace(struct mbuf *m0, int skip, int hlen, int *off) 55 { 56 struct mbuf *m; 57 unsigned remain; 58 59 IPSEC_ASSERT(m0 != NULL, ("null mbuf")); 60 IPSEC_ASSERT(hlen < MHLEN, ("hlen too big: %u", hlen)); 61 62 for (m = m0; m && skip > m->m_len; m = m->m_next) 63 skip -= m->m_len; 64 if (m == NULL) 65 return (NULL); 66 /* 67 * At this point skip is the offset into the mbuf m 68 * where the new header should be placed. Figure out 69 * if there's space to insert the new header. If so, 70 * and copying the remainder makes sense then do so. 71 * Otherwise insert a new mbuf in the chain, splitting 72 * the contents of m as needed. 73 */ 74 remain = m->m_len - skip; /* data to move */ 75 if (remain > skip && 76 hlen + max_linkhdr < M_LEADINGSPACE(m)) { 77 /* 78 * mbuf has enough free space at the beginning. 79 * XXX: which operation is the most heavy - copying of 80 * possible several hundred of bytes or allocation 81 * of new mbuf? We can remove max_linkhdr check 82 * here, but it is possible that this will lead 83 * to allocation of new mbuf in Layer 2 code. 84 */ 85 m->m_data -= hlen; 86 bcopy(mtodo(m, hlen), mtod(m, caddr_t), skip); 87 m->m_len += hlen; 88 *off = skip; 89 } else if (hlen > M_TRAILINGSPACE(m)) { 90 struct mbuf *n0, *n, **np; 91 int todo, len, done; 92 93 n0 = NULL; 94 np = &n0; 95 done = 0; 96 todo = remain; 97 while (todo > 0) { 98 if (todo > MHLEN) { 99 n = m_getcl(M_NOWAIT, m->m_type, 0); 100 len = MCLBYTES; 101 } 102 else { 103 n = m_get(M_NOWAIT, m->m_type); 104 len = MHLEN; 105 } 106 if (n == NULL) { 107 m_freem(n0); 108 return NULL; 109 } 110 *np = n; 111 np = &n->m_next; 112 len = min(todo, len); 113 memcpy(n->m_data, mtod(m, char *) + skip + done, len); 114 n->m_len = len; 115 done += len; 116 todo -= len; 117 } 118 119 if (hlen <= M_TRAILINGSPACE(m) + remain) { 120 m->m_len = skip + hlen; 121 *off = skip; 122 if (n0 != NULL) { 123 *np = m->m_next; 124 m->m_next = n0; 125 } 126 } 127 else { 128 n = m_get(M_NOWAIT, m->m_type); 129 if (n == NULL) { 130 m_freem(n0); 131 return NULL; 132 } 133 134 if ((n->m_next = n0) == NULL) 135 np = &n->m_next; 136 n0 = n; 137 138 *np = m->m_next; 139 m->m_next = n0; 140 141 n->m_len = hlen; 142 m->m_len = skip; 143 144 m = n; /* header is at front ... */ 145 *off = 0; /* ... of new mbuf */ 146 } 147 IPSECSTAT_INC(ips_mbinserted); 148 } else { 149 /* 150 * Copy the remainder to the back of the mbuf 151 * so there's space to write the new header. 152 */ 153 bcopy(mtod(m, caddr_t) + skip, 154 mtod(m, caddr_t) + skip + hlen, remain); 155 m->m_len += hlen; 156 *off = skip; 157 } 158 m0->m_pkthdr.len += hlen; /* adjust packet length */ 159 return m; 160 } 161 162 /* 163 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header 164 * length is updated, and a pointer to the first byte of the padding 165 * (which is guaranteed to be all in one mbuf) is returned. 166 */ 167 caddr_t 168 m_pad(struct mbuf *m, int n) 169 { 170 struct mbuf *m0, *m1; 171 int len, pad; 172 caddr_t retval; 173 174 if (n <= 0) { /* No stupid arguments. */ 175 DPRINTF(("%s: pad length invalid (%d)\n", __func__, n)); 176 m_freem(m); 177 return NULL; 178 } 179 180 len = m->m_pkthdr.len; 181 pad = n; 182 m0 = m; 183 184 while (m0->m_len < len) { 185 len -= m0->m_len; 186 m0 = m0->m_next; 187 } 188 189 if (m0->m_len != len) { 190 DPRINTF(("%s: length mismatch (should be %d instead of %d)\n", 191 __func__, m->m_pkthdr.len, 192 m->m_pkthdr.len + m0->m_len - len)); 193 194 m_freem(m); 195 return NULL; 196 } 197 198 /* Check for zero-length trailing mbufs, and find the last one. */ 199 for (m1 = m0; m1->m_next; m1 = m1->m_next) { 200 if (m1->m_next->m_len != 0) { 201 DPRINTF(("%s: length mismatch (should be %d instead " 202 "of %d)\n", __func__, 203 m->m_pkthdr.len, 204 m->m_pkthdr.len + m1->m_next->m_len)); 205 206 m_freem(m); 207 return NULL; 208 } 209 210 m0 = m1->m_next; 211 } 212 213 if (pad > M_TRAILINGSPACE(m0)) { 214 /* Add an mbuf to the chain. */ 215 MGET(m1, M_NOWAIT, MT_DATA); 216 if (m1 == NULL) { 217 m_freem(m0); 218 DPRINTF(("%s: unable to get extra mbuf\n", __func__)); 219 return NULL; 220 } 221 222 m0->m_next = m1; 223 m0 = m1; 224 m0->m_len = 0; 225 } 226 227 retval = m0->m_data + m0->m_len; 228 m0->m_len += pad; 229 m->m_pkthdr.len += pad; 230 231 return retval; 232 } 233 234 /* 235 * Remove hlen data at offset skip in the packet. This is used by 236 * the protocols strip protocol headers and associated data (e.g. IV, 237 * authenticator) on input. 238 */ 239 int 240 m_striphdr(struct mbuf *m, int skip, int hlen) 241 { 242 struct mbuf *m1; 243 int roff; 244 245 /* Find beginning of header */ 246 m1 = m_getptr(m, skip, &roff); 247 if (m1 == NULL) 248 return (EINVAL); 249 250 /* Remove the header and associated data from the mbuf. */ 251 if (roff == 0) { 252 /* The header was at the beginning of the mbuf */ 253 IPSECSTAT_INC(ips_input_front); 254 m_adj(m1, hlen); 255 if (m1 != m) 256 m->m_pkthdr.len -= hlen; 257 } else if (roff + hlen >= m1->m_len) { 258 struct mbuf *mo; 259 int adjlen; 260 261 /* 262 * Part or all of the header is at the end of this mbuf, 263 * so first let's remove the remainder of the header from 264 * the beginning of the remainder of the mbuf chain, if any. 265 */ 266 IPSECSTAT_INC(ips_input_end); 267 if (roff + hlen > m1->m_len) { 268 adjlen = roff + hlen - m1->m_len; 269 270 /* Adjust the next mbuf by the remainder */ 271 m_adj(m1->m_next, adjlen); 272 273 /* The second mbuf is guaranteed not to have a pkthdr... */ 274 m->m_pkthdr.len -= adjlen; 275 } 276 277 /* Now, let's unlink the mbuf chain for a second...*/ 278 mo = m1->m_next; 279 m1->m_next = NULL; 280 281 /* ...and trim the end of the first part of the chain...sick */ 282 adjlen = m1->m_len - roff; 283 m_adj(m1, -adjlen); 284 if (m1 != m) 285 m->m_pkthdr.len -= adjlen; 286 287 /* Finally, let's relink */ 288 m1->m_next = mo; 289 } else { 290 /* 291 * The header lies in the "middle" of the mbuf; copy 292 * the remainder of the mbuf down over the header. 293 */ 294 IPSECSTAT_INC(ips_input_middle); 295 bcopy(mtod(m1, u_char *) + roff + hlen, 296 mtod(m1, u_char *) + roff, 297 m1->m_len - (roff + hlen)); 298 m1->m_len -= hlen; 299 m->m_pkthdr.len -= hlen; 300 } 301 return (0); 302 } 303 304 /* 305 * Diagnostic routine to check mbuf alignment as required by the 306 * crypto device drivers (that use DMA). 307 */ 308 void 309 m_checkalignment(const char* where, struct mbuf *m0, int off, int len) 310 { 311 int roff; 312 struct mbuf *m = m_getptr(m0, off, &roff); 313 caddr_t addr; 314 315 if (m == NULL) 316 return; 317 printf("%s (off %u len %u): ", where, off, len); 318 addr = mtod(m, caddr_t) + roff; 319 do { 320 int mlen; 321 322 if (((uintptr_t) addr) & 3) { 323 printf("addr misaligned %p,", addr); 324 break; 325 } 326 mlen = m->m_len; 327 if (mlen > len) 328 mlen = len; 329 len -= mlen; 330 if (len && (mlen & 3)) { 331 printf("len mismatch %u,", mlen); 332 break; 333 } 334 m = m->m_next; 335 addr = m ? mtod(m, caddr_t) : NULL; 336 } while (m && len > 0); 337 for (m = m0; m; m = m->m_next) 338 printf(" [%p:%u]", mtod(m, caddr_t), m->m_len); 339 printf("\n"); 340 } 341