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 <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, alloc; 92 93 n0 = NULL; 94 np = &n0; 95 alloc = 0; 96 done = 0; 97 todo = remain; 98 while (todo > 0) { 99 if (todo > MHLEN) { 100 n = m_getcl(M_NOWAIT, m->m_type, 0); 101 len = MCLBYTES; 102 } 103 else { 104 n = m_get(M_NOWAIT, m->m_type); 105 len = MHLEN; 106 } 107 if (n == NULL) { 108 m_freem(n0); 109 return NULL; 110 } 111 *np = n; 112 np = &n->m_next; 113 alloc++; 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 alloc++; 136 137 if ((n->m_next = n0) == NULL) 138 np = &n->m_next; 139 n0 = n; 140 141 *np = m->m_next; 142 m->m_next = n0; 143 144 n->m_len = hlen; 145 m->m_len = skip; 146 147 m = n; /* header is at front ... */ 148 *off = 0; /* ... of new mbuf */ 149 } 150 IPSECSTAT_INC(ips_mbinserted); 151 } else { 152 /* 153 * Copy the remainder to the back of the mbuf 154 * so there's space to write the new header. 155 */ 156 bcopy(mtod(m, caddr_t) + skip, 157 mtod(m, caddr_t) + skip + hlen, remain); 158 m->m_len += hlen; 159 *off = skip; 160 } 161 m0->m_pkthdr.len += hlen; /* adjust packet length */ 162 return m; 163 } 164 165 /* 166 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header 167 * length is updated, and a pointer to the first byte of the padding 168 * (which is guaranteed to be all in one mbuf) is returned. 169 */ 170 caddr_t 171 m_pad(struct mbuf *m, int n) 172 { 173 struct mbuf *m0, *m1; 174 int len, pad; 175 caddr_t retval; 176 177 if (n <= 0) { /* No stupid arguments. */ 178 DPRINTF(("%s: pad length invalid (%d)\n", __func__, n)); 179 m_freem(m); 180 return NULL; 181 } 182 183 len = m->m_pkthdr.len; 184 pad = n; 185 m0 = m; 186 187 while (m0->m_len < len) { 188 len -= m0->m_len; 189 m0 = m0->m_next; 190 } 191 192 if (m0->m_len != len) { 193 DPRINTF(("%s: length mismatch (should be %d instead of %d)\n", 194 __func__, m->m_pkthdr.len, 195 m->m_pkthdr.len + m0->m_len - len)); 196 197 m_freem(m); 198 return NULL; 199 } 200 201 /* Check for zero-length trailing mbufs, and find the last one. */ 202 for (m1 = m0; m1->m_next; m1 = m1->m_next) { 203 if (m1->m_next->m_len != 0) { 204 DPRINTF(("%s: length mismatch (should be %d instead " 205 "of %d)\n", __func__, 206 m->m_pkthdr.len, 207 m->m_pkthdr.len + m1->m_next->m_len)); 208 209 m_freem(m); 210 return NULL; 211 } 212 213 m0 = m1->m_next; 214 } 215 216 if (pad > M_TRAILINGSPACE(m0)) { 217 /* Add an mbuf to the chain. */ 218 MGET(m1, M_NOWAIT, MT_DATA); 219 if (m1 == NULL) { 220 m_freem(m0); 221 DPRINTF(("%s: unable to get extra mbuf\n", __func__)); 222 return NULL; 223 } 224 225 m0->m_next = m1; 226 m0 = m1; 227 m0->m_len = 0; 228 } 229 230 retval = m0->m_data + m0->m_len; 231 m0->m_len += pad; 232 m->m_pkthdr.len += pad; 233 234 return retval; 235 } 236 237 /* 238 * Remove hlen data at offset skip in the packet. This is used by 239 * the protocols strip protocol headers and associated data (e.g. IV, 240 * authenticator) on input. 241 */ 242 int 243 m_striphdr(struct mbuf *m, int skip, int hlen) 244 { 245 struct mbuf *m1; 246 int roff; 247 248 /* Find beginning of header */ 249 m1 = m_getptr(m, skip, &roff); 250 if (m1 == NULL) 251 return (EINVAL); 252 253 /* Remove the header and associated data from the mbuf. */ 254 if (roff == 0) { 255 /* The header was at the beginning of the mbuf */ 256 IPSECSTAT_INC(ips_input_front); 257 m_adj(m1, hlen); 258 if (m1 != m) 259 m->m_pkthdr.len -= hlen; 260 } else if (roff + hlen >= m1->m_len) { 261 struct mbuf *mo; 262 int adjlen; 263 264 /* 265 * Part or all of the header is at the end of this mbuf, 266 * so first let's remove the remainder of the header from 267 * the beginning of the remainder of the mbuf chain, if any. 268 */ 269 IPSECSTAT_INC(ips_input_end); 270 if (roff + hlen > m1->m_len) { 271 adjlen = roff + hlen - m1->m_len; 272 273 /* Adjust the next mbuf by the remainder */ 274 m_adj(m1->m_next, adjlen); 275 276 /* The second mbuf is guaranteed not to have a pkthdr... */ 277 m->m_pkthdr.len -= adjlen; 278 } 279 280 /* Now, let's unlink the mbuf chain for a second...*/ 281 mo = m1->m_next; 282 m1->m_next = NULL; 283 284 /* ...and trim the end of the first part of the chain...sick */ 285 adjlen = m1->m_len - roff; 286 m_adj(m1, -adjlen); 287 if (m1 != m) 288 m->m_pkthdr.len -= adjlen; 289 290 /* Finally, let's relink */ 291 m1->m_next = mo; 292 } else { 293 /* 294 * The header lies in the "middle" of the mbuf; copy 295 * the remainder of the mbuf down over the header. 296 */ 297 IPSECSTAT_INC(ips_input_middle); 298 bcopy(mtod(m1, u_char *) + roff + hlen, 299 mtod(m1, u_char *) + roff, 300 m1->m_len - (roff + hlen)); 301 m1->m_len -= hlen; 302 m->m_pkthdr.len -= hlen; 303 } 304 return (0); 305 } 306 307 /* 308 * Diagnostic routine to check mbuf alignment as required by the 309 * crypto device drivers (that use DMA). 310 */ 311 void 312 m_checkalignment(const char* where, struct mbuf *m0, int off, int len) 313 { 314 int roff; 315 struct mbuf *m = m_getptr(m0, off, &roff); 316 caddr_t addr; 317 318 if (m == NULL) 319 return; 320 printf("%s (off %u len %u): ", where, off, len); 321 addr = mtod(m, caddr_t) + roff; 322 do { 323 int mlen; 324 325 if (((uintptr_t) addr) & 3) { 326 printf("addr misaligned %p,", addr); 327 break; 328 } 329 mlen = m->m_len; 330 if (mlen > len) 331 mlen = len; 332 len -= mlen; 333 if (len && (mlen & 3)) { 334 printf("len mismatch %u,", mlen); 335 break; 336 } 337 m = m->m_next; 338 addr = m ? mtod(m, caddr_t) : NULL; 339 } while (m && len > 0); 340 for (m = m0; m; m = m->m_next) 341 printf(" [%p:%u]", mtod(m, caddr_t), m->m_len); 342 printf("\n"); 343 } 344