NetBSD-5.0.2/sys/netipsec/ipsec_mbuf.c
/* $NetBSD: ipsec_mbuf.c,v 1.11 2008/04/23 06:09:05 thorpej Exp $ */
/*-
* Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: /repoman/r/ncvs/src/sys/netipsec/ipsec_mbuf.c,v 1.5.2.2 2003/03/28 20:32:53 sam Exp $
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ipsec_mbuf.c,v 1.11 2008/04/23 06:09:05 thorpej Exp $");
/*
* IPsec-specific mbuf routines.
*/
#ifdef __FreeBSD__
#include "opt_param.h"
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netipsec/ipsec.h>
#include <netipsec/ipsec_var.h>
#include <netipsec/ipsec_private.h>
#include <netipsec/ipsec_osdep.h>
#include <net/net_osdep.h>
extern struct mbuf *m_getptr(struct mbuf *, int, int *);
/*
* Create a writable copy of the mbuf chain. While doing this
* we compact the chain with a goal of producing a chain with
* at most two mbufs. The second mbuf in this chain is likely
* to be a cluster. The primary purpose of this work is to create
* a writable packet for encryption, compression, etc. The
* secondary goal is to linearize the data so the data can be
* passed to crypto hardware in the most efficient manner possible.
*/
struct mbuf *
m_clone(struct mbuf *m0)
{
struct mbuf *m, *mprev;
struct mbuf *n, *mfirst, *mlast;
int len, off;
IPSEC_ASSERT(m0 != NULL, ("m_clone: null mbuf"));
mprev = NULL;
for (m = m0; m != NULL; m = mprev->m_next) {
/*
* Regular mbufs are ignored unless there's a cluster
* in front of it that we can use to coalesce. We do
* the latter mainly so later clusters can be coalesced
* also w/o having to handle them specially (i.e. convert
* mbuf+cluster -> cluster). This optimization is heavily
* influenced by the assumption that we're running over
* Ethernet where MCLBYTES is large enough that the max
* packet size will permit lots of coalescing into a
* single cluster. This in turn permits efficient
* crypto operations, especially when using hardware.
*/
if ((m->m_flags & M_EXT) == 0) {
if (mprev && (mprev->m_flags & M_EXT) &&
m->m_len <= M_TRAILINGSPACE(mprev)) {
/* XXX: this ignores mbuf types */
memcpy(mtod(mprev, char *) + mprev->m_len,
mtod(m, char *), m->m_len);
mprev->m_len += m->m_len;
mprev->m_next = m->m_next; /* unlink from chain */
m_free(m); /* reclaim mbuf */
IPSEC_STATINC(IPSEC_STAT_MBCOALESCED);
} else {
mprev = m;
}
continue;
}
/*
* Writable mbufs are left alone (for now). Note
* that for 4.x systems it's not possible to identify
* whether or not mbufs with external buffers are
* writable unless they use clusters.
*/
if (M_EXT_WRITABLE(m)) {
mprev = m;
continue;
}
/*
* Not writable, replace with a copy or coalesce with
* the previous mbuf if possible (since we have to copy
* it anyway, we try to reduce the number of mbufs and
* clusters so that future work is easier).
*/
IPSEC_ASSERT(m->m_flags & M_EXT,
("m_clone: m_flags 0x%x", m->m_flags));
/* NB: we only coalesce into a cluster or larger */
if (mprev != NULL && (mprev->m_flags & M_EXT) &&
m->m_len <= M_TRAILINGSPACE(mprev)) {
/* XXX: this ignores mbuf types */
memcpy(mtod(mprev, char *) + mprev->m_len,
mtod(m, char *), m->m_len);
mprev->m_len += m->m_len;
mprev->m_next = m->m_next; /* unlink from chain */
m_free(m); /* reclaim mbuf */
IPSEC_STATINC(IPSEC_STAT_CLCOALESCED);
continue;
}
/*
* Allocate new space to hold the copy...
*/
/* XXX why can M_PKTHDR be set past the first mbuf? */
if (mprev == NULL && (m->m_flags & M_PKTHDR)) {
/*
* NB: if a packet header is present we must
* allocate the mbuf separately from any cluster
* because M_MOVE_PKTHDR will smash the data
* pointer and drop the M_EXT marker.
*/
MGETHDR(n, M_DONTWAIT, m->m_type);
if (n == NULL) {
m_freem(m0);
return (NULL);
}
M_MOVE_PKTHDR(n, m);
MCLGET(n, M_DONTWAIT);
if ((n->m_flags & M_EXT) == 0) {
m_free(n);
m_freem(m0);
return (NULL);
}
} else {
n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags);
if (n == NULL) {
m_freem(m0);
return (NULL);
}
}
/*
* ... and copy the data. We deal with jumbo mbufs
* (i.e. m_len > MCLBYTES) by splitting them into
* clusters. We could just malloc a buffer and make
* it external but too many device drivers don't know
* how to break up the non-contiguous memory when
* doing DMA.
*/
len = m->m_len;
off = 0;
mfirst = n;
mlast = NULL;
for (;;) {
int cc = min(len, MCLBYTES);
memcpy(mtod(n, char *), mtod(m, char *) + off, cc);
n->m_len = cc;
if (mlast != NULL)
mlast->m_next = n;
mlast = n;
IPSEC_STATINC(IPSEC_STAT_CLCOPIED);
len -= cc;
if (len <= 0)
break;
off += cc;
n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags);
if (n == NULL) {
m_freem(mfirst);
m_freem(m0);
return (NULL);
}
}
n->m_next = m->m_next;
if (mprev == NULL)
m0 = mfirst; /* new head of chain */
else
mprev->m_next = mfirst; /* replace old mbuf */
m_free(m); /* release old mbuf */
mprev = mfirst;
}
return (m0);
}
/*
* Make space for a new header of length hlen at skip bytes
* into the packet. When doing this we allocate new mbufs only
* when absolutely necessary. The mbuf where the new header
* is to go is returned together with an offset into the mbuf.
* If NULL is returned then the mbuf chain may have been modified;
* the caller is assumed to always free the chain.
*/
struct mbuf *
m_makespace(struct mbuf *m0, int skip, int hlen, int *off)
{
struct mbuf *m;
unsigned remain;
IPSEC_ASSERT(m0 != NULL, ("m_dmakespace: null mbuf"));
IPSEC_ASSERT(hlen < MHLEN, ("m_makespace: hlen too big: %u", hlen));
for (m = m0; m && skip > m->m_len; m = m->m_next)
skip -= m->m_len;
if (m == NULL)
return (NULL);
/*
* At this point skip is the offset into the mbuf m
* where the new header should be placed. Figure out
* if there's space to insert the new header. If so,
* and copying the remainder makese sense then do so.
* Otherwise insert a new mbuf in the chain, splitting
* the contents of m as needed.
*/
remain = m->m_len - skip; /* data to move */
if (hlen > M_TRAILINGSPACE(m)) {
struct mbuf *n0, *n, **np;
int todo, len, done, alloc;
n0 = NULL;
np = &n0;
alloc = 0;
done = 0;
todo = remain;
while (todo > 0) {
if (todo > MHLEN) {
n = m_getcl(M_DONTWAIT, m->m_type, 0);
len = MCLBYTES;
}
else {
n = m_get(M_DONTWAIT, m->m_type);
len = MHLEN;
}
if (n == NULL) {
m_freem(n0);
return NULL;
}
*np = n;
np = &n->m_next;
alloc++;
len = min(todo, len);
memcpy(n->m_data, mtod(m, char *) + skip + done, len);
n->m_len = len;
done += len;
todo -= len;
}
if (hlen <= M_TRAILINGSPACE(m) + remain) {
m->m_len = skip + hlen;
*off = skip;
if (n0 != NULL) {
*np = m->m_next;
m->m_next = n0;
}
}
else {
n = m_get(M_DONTWAIT, m->m_type);
if (n == NULL) {
m_freem(n0);
return NULL;
}
alloc++;
if ((n->m_next = n0) == NULL)
np = &n->m_next;
n0 = n;
*np = m->m_next;
m->m_next = n0;
n->m_len = hlen;
m->m_len = skip;
m = n; /* header is at front ... */
*off = 0; /* ... of new mbuf */
}
IPSEC_STATADD(IPSEC_STAT_MBINSERTED, alloc);
} else {
/*
* Copy the remainder to the back of the mbuf
* so there's space to write the new header.
*/
/* XXX can this be memcpy? does it handle overlap? */
ovbcopy(mtod(m, char *) + skip,
mtod(m, char *) + skip + hlen, remain);
m->m_len += hlen;
*off = skip;
}
m0->m_pkthdr.len += hlen; /* adjust packet length */
return m;
}
/*
* m_pad(m, n) pads <m> with <n> bytes at the end. The packet header
* length is updated, and a pointer to the first byte of the padding
* (which is guaranteed to be all in one mbuf) is returned.
*/
void *
m_pad(struct mbuf *m, int n)
{
register struct mbuf *m0, *m1;
register int len, pad;
void *retval;
if (n <= 0) { /* No stupid arguments. */
DPRINTF(("m_pad: pad length invalid (%d)\n", n));
m_freem(m);
return NULL;
}
len = m->m_pkthdr.len;
pad = n;
m0 = m;
while (m0->m_len < len) {
IPSEC_ASSERT(m0->m_next != NULL, ("m_pad: m0 null, len %u m_len %u", len, m0->m_len));/*XXX*/
len -= m0->m_len;
m0 = m0->m_next;
}
if (m0->m_len != len) {
DPRINTF(("m_pad: length mismatch (should be %d instead of %d)\n",
m->m_pkthdr.len, m->m_pkthdr.len + m0->m_len - len));
m_freem(m);
return NULL;
}
/* Check for zero-length trailing mbufs, and find the last one. */
for (m1 = m0; m1->m_next; m1 = m1->m_next) {
if (m1->m_next->m_len != 0) {
DPRINTF(("m_pad: length mismatch (should be %d "
"instead of %d)\n",
m->m_pkthdr.len,
m->m_pkthdr.len + m1->m_next->m_len));
m_freem(m);
return NULL;
}
m0 = m1->m_next;
}
if (pad > M_TRAILINGSPACE(m0)) {
/* Add an mbuf to the chain. */
MGET(m1, M_DONTWAIT, MT_DATA);
if (m1 == 0) {
m_freem(m0);
DPRINTF(("m_pad: unable to get extra mbuf\n"));
return NULL;
}
m0->m_next = m1;
m0 = m1;
m0->m_len = 0;
}
retval = m0->m_data + m0->m_len;
m0->m_len += pad;
m->m_pkthdr.len += pad;
return retval;
}
/*
* Remove hlen data at offset skip in the packet. This is used by
* the protocols strip protocol headers and associated data (e.g. IV,
* authenticator) on input.
*/
int
m_striphdr(struct mbuf *m, int skip, int hlen)
{
struct mbuf *m1;
int roff;
/* Find beginning of header */
m1 = m_getptr(m, skip, &roff);
if (m1 == NULL)
return (EINVAL);
/* Remove the header and associated data from the mbuf. */
if (roff == 0) {
/* The header was at the beginning of the mbuf */
IPSEC_STATINC(IPSEC_STAT_INPUT_FRONT);
m_adj(m1, hlen);
if ((m1->m_flags & M_PKTHDR) == 0)
m->m_pkthdr.len -= hlen;
} else if (roff + hlen >= m1->m_len) {
struct mbuf *mo;
/*
* Part or all of the header is at the end of this mbuf,
* so first let's remove the remainder of the header from
* the beginning of the remainder of the mbuf chain, if any.
*/
IPSEC_STATINC(IPSEC_STAT_INPUT_END);
if (roff + hlen > m1->m_len) {
/* Adjust the next mbuf by the remainder */
m_adj(m1->m_next, roff + hlen - m1->m_len);
/* The second mbuf is guaranteed not to have a pkthdr... */
m->m_pkthdr.len -= (roff + hlen - m1->m_len);
}
/* Now, let's unlink the mbuf chain for a second...*/
mo = m1->m_next;
m1->m_next = NULL;
/* ...and trim the end of the first part of the chain...sick */
m_adj(m1, -(m1->m_len - roff));
if ((m1->m_flags & M_PKTHDR) == 0)
m->m_pkthdr.len -= (m1->m_len - roff);
/* Finally, let's relink */
m1->m_next = mo;
} else {
/*
* The header lies in the "middle" of the mbuf; copy
* the remainder of the mbuf down over the header.
*/
IPSEC_STATINC(IPSEC_STAT_INPUT_MIDDLE);
ovbcopy(mtod(m1, u_char *) + roff + hlen,
mtod(m1, u_char *) + roff,
m1->m_len - (roff + hlen));
m1->m_len -= hlen;
m->m_pkthdr.len -= hlen;
}
return (0);
}
/*
* Diagnostic routine to check mbuf alignment as required by the
* crypto device drivers (that use DMA).
*/
void
m_checkalignment(const char* where, struct mbuf *m0, int off, int len)
{
int roff;
struct mbuf *m = m_getptr(m0, off, &roff);
void *addr;
if (m == NULL)
return;
printf("%s (off %u len %u): ", where, off, len);
addr = mtod(m, char *) + roff;
do {
int mlen;
if (((uintptr_t) addr) & 3) {
printf("addr misaligned %p,", addr);
break;
}
mlen = m->m_len;
if (mlen > len)
mlen = len;
len -= mlen;
if (len && (mlen & 3)) {
printf("len mismatch %u,", mlen);
break;
}
m = m->m_next;
addr = m ? mtod(m, void *) : NULL;
} while (m && len > 0);
for (m = m0; m; m = m->m_next)
printf(" [%p:%u]", mtod(m, void *), m->m_len);
printf("\n");
}