/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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.
*
* $FreeBSD$
*/
/*
* IPsec-specific mbuf routines.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netipsec/ipsec.h>
/*
* 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, ("null mbuf"));
IPSEC_ASSERT(hlen < MHLEN, ("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 makes 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 (remain > skip &&
hlen + max_linkhdr < M_LEADINGSPACE(m)) {
/*
* mbuf has enough free space at the beginning.
* XXX: which operation is the most heavy - copying of
* possible several hundred of bytes or allocation
* of new mbuf? We can remove max_linkhdr check
* here, but it is possible that this will lead
* to allocation of new mbuf in Layer 2 code.
*/
m->m_data -= hlen;
bcopy(mtodo(m, hlen), mtod(m, caddr_t), skip);
m->m_len += hlen;
*off = skip;
} else 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_NOWAIT, m->m_type, 0);
len = MCLBYTES;
}
else {
n = m_get(M_NOWAIT, 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_NOWAIT, 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 */
}
IPSECSTAT_INC(ips_mbinserted);
} else {
/*
* Copy the remainder to the back of the mbuf
* so there's space to write the new header.
*/
bcopy(mtod(m, caddr_t) + skip,
mtod(m, caddr_t) + 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.
*/
caddr_t
m_pad(struct mbuf *m, int n)
{
struct mbuf *m0, *m1;
int len, pad;
caddr_t retval;
if (n <= 0) { /* No stupid arguments. */
DPRINTF(("%s: pad length invalid (%d)\n", __func__, n));
m_freem(m);
return NULL;
}
len = m->m_pkthdr.len;
pad = n;
m0 = m;
while (m0->m_len < len) {
len -= m0->m_len;
m0 = m0->m_next;
}
if (m0->m_len != len) {
DPRINTF(("%s: length mismatch (should be %d instead of %d)\n",
__func__, 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(("%s: length mismatch (should be %d instead "
"of %d)\n", __func__,
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_NOWAIT, MT_DATA);
if (m1 == NULL) {
m_freem(m0);
DPRINTF(("%s: unable to get extra mbuf\n", __func__));
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 */
IPSECSTAT_INC(ips_input_front);
m_adj(m1, hlen);
if (m1 != m)
m->m_pkthdr.len -= hlen;
} else if (roff + hlen >= m1->m_len) {
struct mbuf *mo;
int adjlen;
/*
* 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.
*/
IPSECSTAT_INC(ips_input_end);
if (roff + hlen > m1->m_len) {
adjlen = roff + hlen - m1->m_len;
/* Adjust the next mbuf by the remainder */
m_adj(m1->m_next, adjlen);
/* The second mbuf is guaranteed not to have a pkthdr... */
m->m_pkthdr.len -= adjlen;
}
/* 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 */
adjlen = m1->m_len - roff;
m_adj(m1, -adjlen);
if (m1 != m)
m->m_pkthdr.len -= adjlen;
/* 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.
*/
IPSECSTAT_INC(ips_input_middle);
bcopy(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);
caddr_t addr;
if (m == NULL)
return;
printf("%s (off %u len %u): ", where, off, len);
addr = mtod(m, caddr_t) + 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, caddr_t) : NULL;
} while (m && len > 0);
for (m = m0; m; m = m->m_next)
printf(" [%p:%u]", mtod(m, caddr_t), m->m_len);
printf("\n");
}
