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