2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
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14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * IPsec-specific mbuf routines.
35 #include "opt_ipsec.h"
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
41 #include <sys/socket.h>
44 #include <netinet/in.h>
45 #include <netipsec/ipsec.h>
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.
56 m_makespace(struct mbuf *m0, int skip, int hlen, int *off)
61 IPSEC_ASSERT(m0 != NULL, ("null mbuf"));
62 IPSEC_ASSERT(hlen < MHLEN, ("hlen too big: %u", hlen));
64 for (m = m0; m && skip > m->m_len; m = m->m_next)
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.
76 remain = m->m_len - skip; /* data to move */
78 hlen + max_linkhdr < M_LEADINGSPACE(m)) {
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.
88 bcopy(mtodo(m, hlen), mtod(m, caddr_t), skip);
91 } else if (hlen > M_TRAILINGSPACE(m)) {
92 struct mbuf *n0, *n, **np;
93 int todo, len, done, alloc;
102 n = m_getcl(M_NOWAIT, m->m_type, 0);
106 n = m_get(M_NOWAIT, m->m_type);
116 len = min(todo, len);
117 memcpy(n->m_data, mtod(m, char *) + skip + done, len);
123 if (hlen <= M_TRAILINGSPACE(m) + remain) {
124 m->m_len = skip + hlen;
132 n = m_get(M_NOWAIT, m->m_type);
139 if ((n->m_next = n0) == NULL)
149 m = n; /* header is at front ... */
150 *off = 0; /* ... of new mbuf */
152 IPSECSTAT_INC(ips_mbinserted);
155 * Copy the remainder to the back of the mbuf
156 * so there's space to write the new header.
158 bcopy(mtod(m, caddr_t) + skip,
159 mtod(m, caddr_t) + skip + hlen, remain);
163 m0->m_pkthdr.len += hlen; /* adjust packet length */
168 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header
169 * length is updated, and a pointer to the first byte of the padding
170 * (which is guaranteed to be all in one mbuf) is returned.
173 m_pad(struct mbuf *m, int n)
175 struct mbuf *m0, *m1;
179 if (n <= 0) { /* No stupid arguments. */
180 DPRINTF(("%s: pad length invalid (%d)\n", __func__, n));
185 len = m->m_pkthdr.len;
189 while (m0->m_len < len) {
194 if (m0->m_len != len) {
195 DPRINTF(("%s: length mismatch (should be %d instead of %d)\n",
196 __func__, m->m_pkthdr.len,
197 m->m_pkthdr.len + m0->m_len - len));
203 /* Check for zero-length trailing mbufs, and find the last one. */
204 for (m1 = m0; m1->m_next; m1 = m1->m_next) {
205 if (m1->m_next->m_len != 0) {
206 DPRINTF(("%s: length mismatch (should be %d instead "
207 "of %d)\n", __func__,
209 m->m_pkthdr.len + m1->m_next->m_len));
218 if (pad > M_TRAILINGSPACE(m0)) {
219 /* Add an mbuf to the chain. */
220 MGET(m1, M_NOWAIT, MT_DATA);
223 DPRINTF(("%s: unable to get extra mbuf\n", __func__));
232 retval = m0->m_data + m0->m_len;
234 m->m_pkthdr.len += pad;
240 * Remove hlen data at offset skip in the packet. This is used by
241 * the protocols strip protocol headers and associated data (e.g. IV,
242 * authenticator) on input.
245 m_striphdr(struct mbuf *m, int skip, int hlen)
250 /* Find beginning of header */
251 m1 = m_getptr(m, skip, &roff);
255 /* Remove the header and associated data from the mbuf. */
257 /* The header was at the beginning of the mbuf */
258 IPSECSTAT_INC(ips_input_front);
261 m->m_pkthdr.len -= hlen;
262 } else if (roff + hlen >= m1->m_len) {
267 * Part or all of the header is at the end of this mbuf,
268 * so first let's remove the remainder of the header from
269 * the beginning of the remainder of the mbuf chain, if any.
271 IPSECSTAT_INC(ips_input_end);
272 if (roff + hlen > m1->m_len) {
273 adjlen = roff + hlen - m1->m_len;
275 /* Adjust the next mbuf by the remainder */
276 m_adj(m1->m_next, adjlen);
278 /* The second mbuf is guaranteed not to have a pkthdr... */
279 m->m_pkthdr.len -= adjlen;
282 /* Now, let's unlink the mbuf chain for a second...*/
286 /* ...and trim the end of the first part of the chain...sick */
287 adjlen = m1->m_len - roff;
290 m->m_pkthdr.len -= adjlen;
292 /* Finally, let's relink */
296 * The header lies in the "middle" of the mbuf; copy
297 * the remainder of the mbuf down over the header.
299 IPSECSTAT_INC(ips_input_middle);
300 bcopy(mtod(m1, u_char *) + roff + hlen,
301 mtod(m1, u_char *) + roff,
302 m1->m_len - (roff + hlen));
304 m->m_pkthdr.len -= hlen;
310 * Diagnostic routine to check mbuf alignment as required by the
311 * crypto device drivers (that use DMA).
314 m_checkalignment(const char* where, struct mbuf *m0, int off, int len)
317 struct mbuf *m = m_getptr(m0, off, &roff);
322 printf("%s (off %u len %u): ", where, off, len);
323 addr = mtod(m, caddr_t) + roff;
327 if (((uintptr_t) addr) & 3) {
328 printf("addr misaligned %p,", addr);
335 if (len && (mlen & 3)) {
336 printf("len mismatch %u,", mlen);
340 addr = m ? mtod(m, caddr_t) : NULL;
341 } while (m && len > 0);
342 for (m = m0; m; m = m->m_next)
343 printf(" [%p:%u]", mtod(m, caddr_t), m->m_len);