2 * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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
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14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * IPsec-specific mbuf routines.
33 #include "opt_param.h"
35 #include <sys/param.h>
36 #include <sys/systm.h>
38 #include <sys/socket.h>
40 #include <net/route.h>
41 #include <netinet/in.h>
43 #include <netipsec/ipsec.h>
46 * Create a writable copy of the mbuf chain. While doing this
47 * we compact the chain with a goal of producing a chain with
48 * at most two mbufs. The second mbuf in this chain is likely
49 * to be a cluster. The primary purpose of this work is to create
50 * a writable packet for encryption, compression, etc. The
51 * secondary goal is to linearize the data so the data can be
52 * passed to crypto hardware in the most efficient manner possible.
55 m_clone(struct mbuf *m0)
57 struct mbuf *m, *mprev;
58 struct mbuf *n, *mfirst, *mlast;
61 IPSEC_ASSERT(m0 != NULL, ("null mbuf"));
64 for (m = m0; m != NULL; m = mprev->m_next) {
66 * Regular mbufs are ignored unless there's a cluster
67 * in front of it that we can use to coalesce. We do
68 * the latter mainly so later clusters can be coalesced
69 * also w/o having to handle them specially (i.e. convert
70 * mbuf+cluster -> cluster). This optimization is heavily
71 * influenced by the assumption that we're running over
72 * Ethernet where MCLBYTES is large enough that the max
73 * packet size will permit lots of coalescing into a
74 * single cluster. This in turn permits efficient
75 * crypto operations, especially when using hardware.
77 if ((m->m_flags & M_EXT) == 0) {
78 if (mprev && (mprev->m_flags & M_EXT) &&
79 m->m_len <= M_TRAILINGSPACE(mprev)) {
80 /* XXX: this ignores mbuf types */
81 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
82 mtod(m, caddr_t), m->m_len);
83 mprev->m_len += m->m_len;
84 mprev->m_next = m->m_next; /* unlink from chain */
85 m_free(m); /* reclaim mbuf */
86 newipsecstat.ips_mbcoalesced++;
93 * Writable mbufs are left alone (for now).
101 * Not writable, replace with a copy or coalesce with
102 * the previous mbuf if possible (since we have to copy
103 * it anyway, we try to reduce the number of mbufs and
104 * clusters so that future work is easier).
106 IPSEC_ASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags));
107 /* NB: we only coalesce into a cluster or larger */
108 if (mprev != NULL && (mprev->m_flags & M_EXT) &&
109 m->m_len <= M_TRAILINGSPACE(mprev)) {
110 /* XXX: this ignores mbuf types */
111 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
112 mtod(m, caddr_t), m->m_len);
113 mprev->m_len += m->m_len;
114 mprev->m_next = m->m_next; /* unlink from chain */
115 m_free(m); /* reclaim mbuf */
116 newipsecstat.ips_clcoalesced++;
121 * Allocate new space to hold the copy...
123 /* XXX why can M_PKTHDR be set past the first mbuf? */
124 if (mprev == NULL && (m->m_flags & M_PKTHDR)) {
126 * NB: if a packet header is present we must
127 * allocate the mbuf separately from any cluster
128 * because M_MOVE_PKTHDR will smash the data
129 * pointer and drop the M_EXT marker.
131 MGETHDR(n, M_DONTWAIT, m->m_type);
137 MCLGET(n, M_DONTWAIT);
138 if ((n->m_flags & M_EXT) == 0) {
144 n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags);
151 * ... and copy the data. We deal with jumbo mbufs
152 * (i.e. m_len > MCLBYTES) by splitting them into
153 * clusters. We could just malloc a buffer and make
154 * it external but too many device drivers don't know
155 * how to break up the non-contiguous memory when
163 int cc = min(len, MCLBYTES);
164 memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc);
169 newipsecstat.ips_clcopied++;
176 n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags);
183 n->m_next = m->m_next;
185 m0 = mfirst; /* new head of chain */
187 mprev->m_next = mfirst; /* replace old mbuf */
188 m_free(m); /* release old mbuf */
195 * Make space for a new header of length hlen at skip bytes
196 * into the packet. When doing this we allocate new mbufs only
197 * when absolutely necessary. The mbuf where the new header
198 * is to go is returned together with an offset into the mbuf.
199 * If NULL is returned then the mbuf chain may have been modified;
200 * the caller is assumed to always free the chain.
203 m_makespace(struct mbuf *m0, int skip, int hlen, int *off)
208 IPSEC_ASSERT(m0 != NULL, ("null mbuf"));
209 IPSEC_ASSERT(hlen < MHLEN, ("hlen too big: %u", hlen));
211 for (m = m0; m && skip > m->m_len; m = m->m_next)
216 * At this point skip is the offset into the mbuf m
217 * where the new header should be placed. Figure out
218 * if there's space to insert the new header. If so,
219 * and copying the remainder makese sense then do so.
220 * Otherwise insert a new mbuf in the chain, splitting
221 * the contents of m as needed.
223 remain = m->m_len - skip; /* data to move */
224 if (hlen > M_TRAILINGSPACE(m)) {
227 /* XXX code doesn't handle clusters XXX */
228 IPSEC_ASSERT(remain < MLEN, ("remainder too big: %u", remain));
230 * Not enough space in m, split the contents
231 * of m, inserting new mbufs as required.
233 * NB: this ignores mbuf types.
235 MGET(n, M_DONTWAIT, MT_DATA);
238 n->m_next = m->m_next; /* splice new mbuf */
240 newipsecstat.ips_mbinserted++;
241 if (hlen <= M_TRAILINGSPACE(m) + remain) {
243 * New header fits in the old mbuf if we copy
244 * the remainder; just do the copy to the new
245 * mbuf and we're good to go.
247 memcpy(mtod(n, caddr_t),
248 mtod(m, caddr_t) + skip, remain);
250 m->m_len = skip + hlen;
254 * No space in the old mbuf for the new header.
255 * Make space in the new mbuf and check the
256 * remainder'd data fits too. If not then we
257 * must allocate an additional mbuf (yech).
260 if (remain + hlen > M_TRAILINGSPACE(n)) {
263 MGET(n2, M_DONTWAIT, MT_DATA);
264 /* NB: new mbuf is on chain, let caller free */
268 memcpy(mtod(n2, caddr_t),
269 mtod(m, caddr_t) + skip, remain);
271 /* splice in second mbuf */
272 n2->m_next = n->m_next;
274 newipsecstat.ips_mbinserted++;
276 memcpy(mtod(n, caddr_t) + hlen,
277 mtod(m, caddr_t) + skip, remain);
282 m = n; /* header is at front ... */
283 *off = 0; /* ... of new mbuf */
287 * Copy the remainder to the back of the mbuf
288 * so there's space to write the new header.
290 bcopy(mtod(m, caddr_t) + skip,
291 mtod(m, caddr_t) + skip + hlen, remain);
295 m0->m_pkthdr.len += hlen; /* adjust packet length */
300 * m_pad(m, n) pads <m> with <n> bytes at the end. The packet header
301 * length is updated, and a pointer to the first byte of the padding
302 * (which is guaranteed to be all in one mbuf) is returned.
305 m_pad(struct mbuf *m, int n)
307 register struct mbuf *m0, *m1;
308 register int len, pad;
311 if (n <= 0) { /* No stupid arguments. */
312 DPRINTF(("%s: pad length invalid (%d)\n", __func__, n));
317 len = m->m_pkthdr.len;
321 while (m0->m_len < len) {
326 if (m0->m_len != len) {
327 DPRINTF(("%s: length mismatch (should be %d instead of %d)\n",
328 __func__, m->m_pkthdr.len,
329 m->m_pkthdr.len + m0->m_len - len));
335 /* Check for zero-length trailing mbufs, and find the last one. */
336 for (m1 = m0; m1->m_next; m1 = m1->m_next) {
337 if (m1->m_next->m_len != 0) {
338 DPRINTF(("%s: length mismatch (should be %d instead "
339 "of %d)\n", __func__,
341 m->m_pkthdr.len + m1->m_next->m_len));
350 if (pad > M_TRAILINGSPACE(m0)) {
351 /* Add an mbuf to the chain. */
352 MGET(m1, M_DONTWAIT, MT_DATA);
355 DPRINTF(("%s: unable to get extra mbuf\n", __func__));
364 retval = m0->m_data + m0->m_len;
366 m->m_pkthdr.len += pad;
372 * Remove hlen data at offset skip in the packet. This is used by
373 * the protocols strip protocol headers and associated data (e.g. IV,
374 * authenticator) on input.
377 m_striphdr(struct mbuf *m, int skip, int hlen)
382 /* Find beginning of header */
383 m1 = m_getptr(m, skip, &roff);
387 /* Remove the header and associated data from the mbuf. */
389 /* The header was at the beginning of the mbuf */
390 newipsecstat.ips_input_front++;
392 if ((m1->m_flags & M_PKTHDR) == 0)
393 m->m_pkthdr.len -= hlen;
394 } else if (roff + hlen >= m1->m_len) {
398 * Part or all of the header is at the end of this mbuf,
399 * so first let's remove the remainder of the header from
400 * the beginning of the remainder of the mbuf chain, if any.
402 newipsecstat.ips_input_end++;
403 if (roff + hlen > m1->m_len) {
404 /* Adjust the next mbuf by the remainder */
405 m_adj(m1->m_next, roff + hlen - m1->m_len);
407 /* The second mbuf is guaranteed not to have a pkthdr... */
408 m->m_pkthdr.len -= (roff + hlen - m1->m_len);
411 /* Now, let's unlink the mbuf chain for a second...*/
415 /* ...and trim the end of the first part of the chain...sick */
416 m_adj(m1, -(m1->m_len - roff));
417 if ((m1->m_flags & M_PKTHDR) == 0)
418 m->m_pkthdr.len -= (m1->m_len - roff);
420 /* Finally, let's relink */
424 * The header lies in the "middle" of the mbuf; copy
425 * the remainder of the mbuf down over the header.
427 newipsecstat.ips_input_middle++;
428 bcopy(mtod(m1, u_char *) + roff + hlen,
429 mtod(m1, u_char *) + roff,
430 m1->m_len - (roff + hlen));
432 m->m_pkthdr.len -= hlen;
438 * Diagnostic routine to check mbuf alignment as required by the
439 * crypto device drivers (that use DMA).
442 m_checkalignment(const char* where, struct mbuf *m0, int off, int len)
445 struct mbuf *m = m_getptr(m0, off, &roff);
450 printf("%s (off %u len %u): ", where, off, len);
451 addr = mtod(m, caddr_t) + roff;
455 if (((uintptr_t) addr) & 3) {
456 printf("addr misaligned %p,", addr);
463 if (len && (mlen & 3)) {
464 printf("len mismatch %u,", mlen);
468 addr = m ? mtod(m, caddr_t) : NULL;
469 } while (m && len > 0);
470 for (m = m0; m; m = m->m_next)
471 printf(" [%p:%u]", mtod(m, caddr_t), m->m_len);