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/*-
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ipsec.h"
#include "opt_sctp.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
#include <netinet/ip_ipsec.h>
#ifdef SCTP
#include <netinet/sctp_crc32.h>
#endif
#include <machine/in_cksum.h>
#include <netipsec/ipsec.h>
#include <netipsec/xform.h>
#include <netipsec/key.h>
extern struct protosw inetsw[];
#ifdef IPSEC_FILTERTUNNEL
static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 1;
#else
static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 0;
#endif
#define V_ip4_ipsec_filtertunnel VNET(ip4_ipsec_filtertunnel)
SYSCTL_DECL(_net_inet_ipsec);
SYSCTL_VNET_INT(_net_inet_ipsec, OID_AUTO, filtertunnel,
CTLFLAG_RW, &VNET_NAME(ip4_ipsec_filtertunnel), 0,
"If set filter packets from an IPsec tunnel.");
/*
* Check if we have to jump over firewall processing for this packet.
* Called from ip_input().
* 1 = jump over firewall, 0 = packet goes through firewall.
*/
int
ip_ipsec_filtertunnel(struct mbuf *m)
{
/*
* Bypass packet filtering for packets previously handled by IPsec.
*/
if (!V_ip4_ipsec_filtertunnel &&
m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
return 1;
return 0;
}
/*
* Check if this packet has an active SA and needs to be dropped instead
* of forwarded.
* Called from ip_forward().
* 1 = drop packet, 0 = forward packet.
*/
int
ip_ipsec_fwd(struct mbuf *m)
{
return (ipsec4_in_reject(m, NULL));
}
/*
* Check if protocol type doesn't have a further header and do IPSEC
* decryption or reject right now. Protocols with further headers get
* their IPSEC treatment within the protocol specific processing.
* Called from ip_input().
* 1 = drop packet, 0 = continue processing packet.
*/
int
ip_ipsec_input(struct mbuf *m, int nxt)
{
/*
* enforce IPsec policy checking if we are seeing last header.
* note that we do not visit this with protocols with pcb layer
* code - like udp/tcp/raw ip.
*/
if ((inetsw[ip_protox[nxt]].pr_flags & PR_LASTHDR) != 0)
return (ipsec4_in_reject(m, NULL));
return (0);
}
/*
* Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
* Called from ip_forward().
* Returns MTU suggestion for ICMP needfrag reply.
*/
int
ip_ipsec_mtu(struct mbuf *m, int mtu)
{
/*
* If the packet is routed over IPsec tunnel, tell the
* originator the tunnel MTU.
* tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
* XXX quickhack!!!
*/
return (mtu - ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL));
}
/*
*
* Called from ip_output().
* 1 = drop packet, 0 = continue processing packet,
* -1 = packet was reinjected and stop processing packet
*/
int
ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *error)
{
struct secpolicy *sp;
if (!key_havesp(IPSEC_DIR_OUTBOUND))
return 0;
/*
* Check the security policy (SP) for the packet and, if
* required, do IPsec-related processing. There are two
* cases here; the first time a packet is sent through
* it will be untagged and handled by ipsec4_checkpolicy.
* If the packet is resubmitted to ip_output (e.g. after
* AH, ESP, etc. processing), there will be a tag to bypass
* the lookup and related policy checking.
*/
if (m_tag_find(*m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) {
*error = 0;
return (0);
}
sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, error, inp);
/*
* There are four return cases:
* sp != NULL apply IPsec policy
* sp == NULL, error == 0 no IPsec handling needed
* sp == NULL, error == -EINVAL discard packet w/o error
* sp == NULL, error != 0 discard packet, report error
*/
if (sp != NULL) {
/*
* Do delayed checksums now because we send before
* this is done in the normal processing path.
*/
if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
in_delayed_cksum(*m);
(*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
}
#ifdef SCTP
if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) {
struct ip *ip = mtod(*m, struct ip *);
sctp_delayed_cksum(*m, (uint32_t)(ip->ip_hl << 2));
(*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP;
}
#endif
/* NB: callee frees mbuf */
*error = ipsec4_process_packet(*m, sp->req);
KEY_FREESP(&sp);
if (*error == EJUSTRETURN) {
/*
* We had a SP with a level of 'use' and no SA. We
* will just continue to process the packet without
* IPsec processing and return without error.
*/
*error = 0;
goto done;
}
/*
* Preserve KAME behaviour: ENOENT can be returned
* when an SA acquire is in progress. Don't propagate
* this to user-level; it confuses applications.
*
* XXX this will go away when the SADB is redone.
*/
if (*error == ENOENT)
*error = 0;
goto reinjected;
} else { /* sp == NULL */
if (*error != 0) {
/*
* Hack: -EINVAL is used to signal that a packet
* should be silently discarded. This is typically
* because we asked key management for an SA and
* it was delayed (e.g. kicked up to IKE).
*/
if (*error == -EINVAL)
*error = 0;
goto bad;
}
/* No IPsec processing for this packet. */
}
done:
return (0);
reinjected:
return (-1);
bad:
if (sp != NULL)
KEY_FREESP(&sp);
return 1;
}
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