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 "opt_param.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/mbuf.h> 38 #include <sys/socket.h> 39 40 #include <net/route.h> 41 #include <net/vnet.h> 42 43 #include <netinet/in.h> 44 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 (hlen > M_TRAILINGSPACE(m)) { 78 struct mbuf *n0, *n, **np; 79 int todo, len, done, alloc; 80 81 n0 = NULL; 82 np = &n0; 83 alloc = 0; 84 done = 0; 85 todo = remain; 86 while (todo > 0) { 87 if (todo > MHLEN) { 88 n = m_getcl(M_DONTWAIT, m->m_type, 0); 89 len = MCLBYTES; 90 } 91 else { 92 n = m_get(M_DONTWAIT, m->m_type); 93 len = MHLEN; 94 } 95 if (n == NULL) { 96 m_freem(n0); 97 return NULL; 98 } 99 *np = n; 100 np = &n->m_next; 101 alloc++; 102 len = min(todo, len); 103 memcpy(n->m_data, mtod(m, char *) + skip + done, len); 104 n->m_len = len; 105 done += len; 106 todo -= len; 107 } 108 109 if (hlen <= M_TRAILINGSPACE(m) + remain) { 110 m->m_len = skip + hlen; 111 *off = skip; 112 if (n0 != NULL) { 113 *np = m->m_next; 114 m->m_next = n0; 115 } 116 } 117 else { 118 n = m_get(M_DONTWAIT, m->m_type); 119 if (n == NULL) { 120 m_freem(n0); 121 return NULL; 122 } 123 alloc++; 124 125 if ((n->m_next = n0) == NULL) 126 np = &n->m_next; 127 n0 = n; 128 129 *np = m->m_next; 130 m->m_next = n0; 131 132 n->m_len = hlen; 133 m->m_len = skip; 134 135 m = n; /* header is at front ... */ 136 *off = 0; /* ... of new mbuf */ 137 } 138 V_ipsec4stat.ips_mbinserted++; 139 } else { 140 /* 141 * Copy the remainder to the back of the mbuf 142 * so there's space to write the new header. 143 */ 144 bcopy(mtod(m, caddr_t) + skip, 145 mtod(m, caddr_t) + skip + hlen, remain); 146 m->m_len += hlen; 147 *off = skip; 148 } 149 m0->m_pkthdr.len += hlen; /* adjust packet length */ 150 return m; 151 } 152 153 /* 154 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header 155 * length is updated, and a pointer to the first byte of the padding 156 * (which is guaranteed to be all in one mbuf) is returned. 157 */ 158 caddr_t 159 m_pad(struct mbuf *m, int n) 160 { 161 register struct mbuf *m0, *m1; 162 register int len, pad; 163 caddr_t retval; 164 165 if (n <= 0) { /* No stupid arguments. */ 166 DPRINTF(("%s: pad length invalid (%d)\n", __func__, n)); 167 m_freem(m); 168 return NULL; 169 } 170 171 len = m->m_pkthdr.len; 172 pad = n; 173 m0 = m; 174 175 while (m0->m_len < len) { 176 len -= m0->m_len; 177 m0 = m0->m_next; 178 } 179 180 if (m0->m_len != len) { 181 DPRINTF(("%s: length mismatch (should be %d instead of %d)\n", 182 __func__, m->m_pkthdr.len, 183 m->m_pkthdr.len + m0->m_len - len)); 184 185 m_freem(m); 186 return NULL; 187 } 188 189 /* Check for zero-length trailing mbufs, and find the last one. */ 190 for (m1 = m0; m1->m_next; m1 = m1->m_next) { 191 if (m1->m_next->m_len != 0) { 192 DPRINTF(("%s: length mismatch (should be %d instead " 193 "of %d)\n", __func__, 194 m->m_pkthdr.len, 195 m->m_pkthdr.len + m1->m_next->m_len)); 196 197 m_freem(m); 198 return NULL; 199 } 200 201 m0 = m1->m_next; 202 } 203 204 if (pad > M_TRAILINGSPACE(m0)) { 205 /* Add an mbuf to the chain. */ 206 MGET(m1, M_DONTWAIT, MT_DATA); 207 if (m1 == 0) { 208 m_freem(m0); 209 DPRINTF(("%s: unable to get extra mbuf\n", __func__)); 210 return NULL; 211 } 212 213 m0->m_next = m1; 214 m0 = m1; 215 m0->m_len = 0; 216 } 217 218 retval = m0->m_data + m0->m_len; 219 m0->m_len += pad; 220 m->m_pkthdr.len += pad; 221 222 return retval; 223 } 224 225 /* 226 * Remove hlen data at offset skip in the packet. This is used by 227 * the protocols strip protocol headers and associated data (e.g. IV, 228 * authenticator) on input. 229 */ 230 int 231 m_striphdr(struct mbuf *m, int skip, int hlen) 232 { 233 struct mbuf *m1; 234 int roff; 235 236 /* Find beginning of header */ 237 m1 = m_getptr(m, skip, &roff); 238 if (m1 == NULL) 239 return (EINVAL); 240 241 /* Remove the header and associated data from the mbuf. */ 242 if (roff == 0) { 243 /* The header was at the beginning of the mbuf */ 244 V_ipsec4stat.ips_input_front++; 245 m_adj(m1, hlen); 246 if ((m1->m_flags & M_PKTHDR) == 0) 247 m->m_pkthdr.len -= hlen; 248 } else if (roff + hlen >= m1->m_len) { 249 struct mbuf *mo; 250 251 /* 252 * Part or all of the header is at the end of this mbuf, 253 * so first let's remove the remainder of the header from 254 * the beginning of the remainder of the mbuf chain, if any. 255 */ 256 V_ipsec4stat.ips_input_end++; 257 if (roff + hlen > m1->m_len) { 258 /* Adjust the next mbuf by the remainder */ 259 m_adj(m1->m_next, roff + hlen - m1->m_len); 260 261 /* The second mbuf is guaranteed not to have a pkthdr... */ 262 m->m_pkthdr.len -= (roff + hlen - m1->m_len); 263 } 264 265 /* Now, let's unlink the mbuf chain for a second...*/ 266 mo = m1->m_next; 267 m1->m_next = NULL; 268 269 /* ...and trim the end of the first part of the chain...sick */ 270 m_adj(m1, -(m1->m_len - roff)); 271 if ((m1->m_flags & M_PKTHDR) == 0) 272 m->m_pkthdr.len -= (m1->m_len - roff); 273 274 /* Finally, let's relink */ 275 m1->m_next = mo; 276 } else { 277 /* 278 * The header lies in the "middle" of the mbuf; copy 279 * the remainder of the mbuf down over the header. 280 */ 281 V_ipsec4stat.ips_input_middle++; 282 bcopy(mtod(m1, u_char *) + roff + hlen, 283 mtod(m1, u_char *) + roff, 284 m1->m_len - (roff + hlen)); 285 m1->m_len -= hlen; 286 m->m_pkthdr.len -= hlen; 287 } 288 return (0); 289 } 290 291 /* 292 * Diagnostic routine to check mbuf alignment as required by the 293 * crypto device drivers (that use DMA). 294 */ 295 void 296 m_checkalignment(const char* where, struct mbuf *m0, int off, int len) 297 { 298 int roff; 299 struct mbuf *m = m_getptr(m0, off, &roff); 300 caddr_t addr; 301 302 if (m == NULL) 303 return; 304 printf("%s (off %u len %u): ", where, off, len); 305 addr = mtod(m, caddr_t) + roff; 306 do { 307 int mlen; 308 309 if (((uintptr_t) addr) & 3) { 310 printf("addr misaligned %p,", addr); 311 break; 312 } 313 mlen = m->m_len; 314 if (mlen > len) 315 mlen = len; 316 len -= mlen; 317 if (len && (mlen & 3)) { 318 printf("len mismatch %u,", mlen); 319 break; 320 } 321 m = m->m_next; 322 addr = m ? mtod(m, caddr_t) : NULL; 323 } while (m && len > 0); 324 for (m = m0; m; m = m->m_next) 325 printf(" [%p:%u]", mtod(m, caddr_t), m->m_len); 326 printf("\n"); 327 } 328