431 lines
11 KiB
C
431 lines
11 KiB
C
/* $NetBSD: ipsec_mbuf.c,v 1.30 2018/12/22 13:11:38 maxv Exp $ */
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/*
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* Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD: sys/netipsec/ipsec_mbuf.c,v 1.5.2.2 2003/03/28 20:32:53 sam Exp $
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: ipsec_mbuf.c,v 1.30 2018/12/22 13:11:38 maxv Exp $");
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/*
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* IPsec-specific mbuf routines.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <netipsec/ipsec.h>
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#include <netipsec/ipsec_var.h>
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#include <netipsec/ipsec_private.h>
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/*
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* Create a writable copy of the mbuf chain. While doing this
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* we compact the chain with a goal of producing a chain with
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* at most two mbufs. The second mbuf in this chain is likely
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* to be a cluster. The primary purpose of this work is to create
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* a writable packet for encryption, compression, etc. The
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* secondary goal is to linearize the data so the data can be
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* passed to crypto hardware in the most efficient manner possible.
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*/
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struct mbuf *
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m_clone(struct mbuf *m0)
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{
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struct mbuf *m, *mprev;
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struct mbuf *n, *mfirst, *mlast;
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int len, off;
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KASSERT(m0 != NULL);
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mprev = NULL;
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for (m = m0; m != NULL; m = mprev->m_next) {
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/*
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* Regular mbufs are ignored unless there's a cluster
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* in front of it that we can use to coalesce.
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*/
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if ((m->m_flags & M_EXT) == 0) {
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if (mprev && (mprev->m_flags & M_EXT) &&
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m->m_len <= M_TRAILINGSPACE(mprev)) {
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memcpy(mtod(mprev, char *) + mprev->m_len,
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mtod(m, char *), m->m_len);
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mprev->m_len += m->m_len;
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mprev->m_next = m_free(m);
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IPSEC_STATINC(IPSEC_STAT_MBCOALESCED);
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} else {
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mprev = m;
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}
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continue;
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}
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/*
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* Writable mbufs are left alone.
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*/
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if (!M_READONLY(m)) {
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mprev = m;
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continue;
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}
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/*
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* Not writable, replace with a copy or coalesce with
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* the previous mbuf if possible (since we have to copy
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* it anyway, we try to reduce the number of mbufs and
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* clusters so that future work is easier).
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*/
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/* We only coalesce into a cluster. */
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if (mprev != NULL && (mprev->m_flags & M_EXT) &&
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m->m_len <= M_TRAILINGSPACE(mprev)) {
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memcpy(mtod(mprev, char *) + mprev->m_len,
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mtod(m, char *), m->m_len);
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mprev->m_len += m->m_len;
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mprev->m_next = m_free(m);
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IPSEC_STATINC(IPSEC_STAT_CLCOALESCED);
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continue;
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}
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/*
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* Allocate new space to hold the copy...
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*/
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if (mprev == NULL && (m->m_flags & M_PKTHDR)) {
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MGETHDR(n, M_DONTWAIT, m->m_type);
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if (n == NULL) {
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m_freem(m0);
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return NULL;
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}
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m_move_pkthdr(n, m);
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MCLGET(n, M_DONTWAIT);
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if ((n->m_flags & M_EXT) == 0) {
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m_free(n);
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m_freem(m0);
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return NULL;
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}
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} else {
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n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags);
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if (n == NULL) {
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m_freem(m0);
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return NULL;
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}
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}
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/*
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* ... and copy the data. We deal with jumbo mbufs
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* (i.e. m_len > MCLBYTES) by splitting them into
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* clusters. We could just malloc a buffer and make
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* it external but too many device drivers don't know
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* how to break up the non-contiguous memory when
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* doing DMA.
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*/
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len = m->m_len;
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off = 0;
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mfirst = n;
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mlast = NULL;
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for (;;) {
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const int cc = uimin(len, MCLBYTES);
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memcpy(mtod(n, char *), mtod(m, char *) + off, cc);
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n->m_len = cc;
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if (mlast != NULL)
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mlast->m_next = n;
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mlast = n;
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IPSEC_STATINC(IPSEC_STAT_CLCOPIED);
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len -= cc;
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if (len <= 0)
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break;
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off += cc;
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n = m_getcl(M_DONTWAIT, m->m_type, m->m_flags);
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if (n == NULL) {
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m_freem(mfirst);
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m_freem(m0);
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return NULL;
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}
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}
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n->m_next = m->m_next;
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if (mprev == NULL)
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m0 = mfirst; /* new head of chain */
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else
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mprev->m_next = mfirst; /* replace old mbuf */
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m_free(m); /* release old mbuf */
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mprev = mfirst;
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}
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return m0;
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}
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/*
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* Make space for a new header of length hlen at skip bytes
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* into the packet. When doing this we allocate new mbufs only
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* when absolutely necessary. The mbuf where the new header
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* is to go is returned together with an offset into the mbuf.
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* If NULL is returned then the mbuf chain may have been modified;
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* the caller is assumed to always free the chain.
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*/
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struct mbuf *
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m_makespace(struct mbuf *m0, int skip, int hlen, int *off)
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{
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struct mbuf *m;
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unsigned remain;
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KASSERT(m0 != NULL);
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KASSERT(m0->m_flags & M_PKTHDR);
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KASSERTMSG(hlen < MHLEN, "hlen too big: %u", hlen);
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for (m = m0; m && skip > m->m_len; m = m->m_next)
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skip -= m->m_len;
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if (m == NULL)
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return NULL;
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/*
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* At this point skip is the offset into the mbuf m
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* where the new header should be placed. Figure out
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* if there's space to insert the new header. If so,
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* and copying the remainder makes sense then do so.
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* Otherwise insert a new mbuf in the chain, splitting
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* the contents of m as needed.
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*/
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remain = m->m_len - skip; /* data to move */
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if (hlen > M_TRAILINGSPACE(m)) {
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struct mbuf *n0, *n, **np;
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int todo, len, done, alloc;
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n0 = NULL;
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np = &n0;
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alloc = 0;
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done = 0;
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todo = remain;
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while (todo > 0) {
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if (todo > MHLEN) {
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n = m_getcl(M_DONTWAIT, m->m_type, 0);
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len = MCLBYTES;
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} else {
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n = m_get(M_DONTWAIT, m->m_type);
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len = MHLEN;
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}
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if (n == NULL) {
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m_freem(n0);
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return NULL;
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}
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*np = n;
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np = &n->m_next;
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alloc++;
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len = uimin(todo, len);
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memcpy(n->m_data, mtod(m, char *) + skip + done, len);
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n->m_len = len;
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done += len;
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todo -= len;
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}
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if (hlen <= M_TRAILINGSPACE(m) + remain) {
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m->m_len = skip + hlen;
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*off = skip;
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if (n0 != NULL) {
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*np = m->m_next;
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m->m_next = n0;
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}
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} else {
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n = m_get(M_DONTWAIT, m->m_type);
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if (n == NULL) {
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m_freem(n0);
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return NULL;
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}
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alloc++;
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if ((n->m_next = n0) == NULL)
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np = &n->m_next;
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n0 = n;
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*np = m->m_next;
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m->m_next = n0;
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n->m_len = hlen;
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m->m_len = skip;
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m = n; /* header is at front ... */
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*off = 0; /* ... of new mbuf */
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}
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IPSEC_STATADD(IPSEC_STAT_MBINSERTED, alloc);
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} else {
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/*
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* Copy the remainder to the back of the mbuf
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* so there's space to write the new header.
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*/
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/* XXX can this be memcpy? does it handle overlap? */
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memmove(mtod(m, char *) + skip + hlen,
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mtod(m, char *) + skip, remain);
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m->m_len += hlen;
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*off = skip;
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}
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m0->m_pkthdr.len += hlen; /* adjust packet length */
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return m;
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}
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/*
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* m_pad(m, n) pads <m> with <n> bytes at the end. The packet header
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* length is updated, and a pointer to the first byte of the padding
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* (which is guaranteed to be all in one mbuf) is returned.
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*/
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void *
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m_pad(struct mbuf *m, int n)
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{
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register struct mbuf *m0, *m1;
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register int len, pad;
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void *retval;
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if (__predict_false(n > MLEN)) {
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panic("%s: %d > MLEN", __func__, n);
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}
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KASSERT(m->m_flags & M_PKTHDR);
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len = m->m_pkthdr.len;
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pad = n;
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m0 = m;
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while (m0->m_len < len) {
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KASSERTMSG(m0->m_next != NULL,
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"m0 null, len %u m_len %u", len, m0->m_len);
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len -= m0->m_len;
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m0 = m0->m_next;
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}
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if (m0->m_len != len) {
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IPSECLOG(LOG_DEBUG,
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"length mismatch (should be %d instead of %d)\n",
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m->m_pkthdr.len, m->m_pkthdr.len + m0->m_len - len);
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m_freem(m);
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return NULL;
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}
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/* Check for zero-length trailing mbufs, and find the last one. */
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for (m1 = m0; m1->m_next; m1 = m1->m_next) {
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if (m1->m_next->m_len != 0) {
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IPSECLOG(LOG_DEBUG,
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"length mismatch (should be %d instead of %d)\n",
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m->m_pkthdr.len,
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m->m_pkthdr.len + m1->m_next->m_len);
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m_freem(m);
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return NULL;
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}
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m0 = m1->m_next;
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}
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if (pad > M_TRAILINGSPACE(m0)) {
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/* Add an mbuf to the chain. */
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MGET(m1, M_DONTWAIT, MT_DATA);
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if (m1 == NULL) {
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m_freem(m);
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IPSECLOG(LOG_DEBUG, "unable to get extra mbuf\n");
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return NULL;
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}
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m0->m_next = m1;
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m0 = m1;
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m0->m_len = 0;
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}
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retval = m0->m_data + m0->m_len;
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m0->m_len += pad;
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m->m_pkthdr.len += pad;
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return retval;
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}
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/*
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* Remove hlen data at offset skip in the packet. This is used by
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* the protocols strip protocol headers and associated data (e.g. IV,
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* authenticator) on input.
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*/
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int
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m_striphdr(struct mbuf *m, int skip, int hlen)
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{
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struct mbuf *m1;
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int roff;
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KASSERT(m->m_flags & M_PKTHDR);
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/* Find beginning of header */
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m1 = m_getptr(m, skip, &roff);
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if (m1 == NULL)
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return EINVAL;
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/* Remove the header and associated data from the mbuf. */
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if (roff == 0) {
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/* The header was at the beginning of the mbuf */
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IPSEC_STATINC(IPSEC_STAT_INPUT_FRONT);
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m_adj(m1, hlen);
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if (m1 != m)
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m->m_pkthdr.len -= hlen;
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} else if (roff + hlen >= m1->m_len) {
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struct mbuf *mo;
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int adjlen;
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/*
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* Part or all of the header is at the end of this mbuf,
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* so first let's remove the remainder of the header from
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* the beginning of the remainder of the mbuf chain, if any.
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*/
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IPSEC_STATINC(IPSEC_STAT_INPUT_END);
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if (roff + hlen > m1->m_len) {
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adjlen = roff + hlen - m1->m_len;
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/* Adjust the next mbuf by the remainder */
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m_adj(m1->m_next, adjlen);
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/* The second mbuf is guaranteed not to have a pkthdr... */
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m->m_pkthdr.len -= adjlen;
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}
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/* Now, let's unlink the mbuf chain for a second...*/
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mo = m1->m_next;
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m1->m_next = NULL;
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/* ...and trim the end of the first part of the chain...sick */
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adjlen = m1->m_len - roff;
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m_adj(m1, -adjlen);
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if (m1 != m)
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m->m_pkthdr.len -= adjlen;
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/* Finally, let's relink */
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m1->m_next = mo;
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} else {
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/*
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* The header lies in the "middle" of the mbuf; copy
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* the remainder of the mbuf down over the header.
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*/
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IPSEC_STATINC(IPSEC_STAT_INPUT_MIDDLE);
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memmove(mtod(m1, u_char *) + roff,
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mtod(m1, u_char *) + roff + hlen,
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m1->m_len - (roff + hlen));
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m1->m_len -= hlen;
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m->m_pkthdr.len -= hlen;
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}
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return 0;
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}
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