Commit Graph

320 Commits

Author SHA1 Message Date
Robert Watson
aed5570872 Complete break-out of sys/sys/mac.h into sys/security/mac/mac_framework.h
begun with a repo-copy of mac.h to mac_framework.h.  sys/mac.h now
contains the userspace and user<->kernel API and definitions, with all
in-kernel interfaces moved to mac_framework.h, which is now included
across most of the kernel instead.

This change is the first step in a larger cleanup and sweep of MAC
Framework interfaces in the kernel, and will not be MFC'd.

Obtained from:	TrustedBSD Project
Sponsored by:	SPARTA
2006-10-22 11:52:19 +00:00
Julian Elischer
010b65f54a revert last change.. premature.. need to wait until if_ethersubr.c
uses pfil to get to ipfw.
2006-10-21 00:16:31 +00:00
Julian Elischer
3df668cc38 Move some variables to a more likely place
and remove "temporary" stuff that is not needed any more.
2006-10-20 19:32:08 +00:00
Julian Elischer
b7522c27d2 Remove the IPFIREWALL_FORWARD_EXTENDED option and make it on by default as it always was
in older versions of FreeBSD. This option is pointless as it is needed in just
about every interesting usage of forward that I have ever seen. It doesn't make
the system any safer and just wastes huge amounts of develper time
when the system doesn't behave as expected when code is moved from
4.x to 6.x It doesn't make
the system any safer and just wastes huge amounts of develper time
when the system doesn't behave as expected when code is moved from
4.x to 6.x  or 7.x
Reviewed by:	glebius
MFC after:	1 week
2006-08-17 00:37:03 +00:00
Max Laier
e93187482d Reintroduce net.inet6.ip6.fw.enable sysctl to dis/enable the ipv6 processing
seperately.  Also use pfil hook/unhook instead of keeping the check
functions in pfil just to return there based on the sysctl.  While here fix
some whitespace on a nearby SYSCTL_ macro.
2006-05-12 04:41:27 +00:00
Pawel Jakub Dawidek
1d7d0bfe5e /tmp/cvsTXPIwQ 2006-05-05 06:24:34 +00:00
Paul Saab
4f590175b7 Allow for nmbclusters and maxsockets to be increased via sysctl.
An eventhandler is used to update all the various zones that depend
on these values.
2006-04-21 09:25:40 +00:00
Oleg Bulyzhin
6edb555dbc Fix five years old bug in ip_reass(): if we are using 'full' (i.e. including
pseudo header) hardware rx checksum offloading ip_reass() fails to calculate
TCP/UDP checksum for reassembled packet correctly.  This also should fix
recent 'NFS over UDP over bge' issue exposed by if_bge.c rev. 1.123

Reviewed by:	sam (earlier version), bde
Approved by:	glebius (mentor)
MFC after:	2 weeks
2006-02-07 11:48:10 +00:00
Christian S.J. Peron
604afec496 Somewhat re-factor the read/write locking mechanism associated with the packet
filtering mechanisms to use the new rwlock(9) locking API:

- Drop the variables stored in the phil_head structure which were specific to
  conditions and the home rolled read/write locking mechanism.
- Drop some includes which were used for condition variables
- Drop the inline functions, and convert them to macros. Also, move these
  macros into pfil.h
- Move pfil list locking macros intp phil.h as well
- Rename ph_busy_count to ph_nhooks. This variable will represent the number
  of IN/OUT hooks registered with the pfil head structure
- Define PFIL_HOOKED macro which evaluates to true if there are any
  hooks to be ran by pfil_run_hooks
- In the IP/IP6 stacks, change the ph_busy_count comparison to use the new
  PFIL_HOOKED macro.
- Drop optimization in pfil_run_hooks which checks to see if there are any
  hooks to be ran, and returns if not. This check is already performed by the
  IP stacks when they call:

        if (!PFIL_HOOKED(ph))
                goto skip_hooks;

- Drop in assertion which makes sure that the number of hooks never drops
  below 0 for good measure. This in theory should never happen, and if it
  does than there are problems somewhere
- Drop special logic around PFIL_WAITOK because rw_wlock(9) does not sleep
- Drop variables which support home rolled read/write locking mechanism from
  the IPFW firewall chain structure.
- Swap out the read/write firewall chain lock internal to use the rwlock(9)
  API instead of our home rolled version
- Convert the inlined functions to macros

Reviewed by:	mlaier, andre, glebius
Thanks to:	jhb for the new locking API
2006-02-02 03:13:16 +00:00
Andre Oppermann
1dfcf0d2a3 Move the IPSEC related code blocks to their own file to unclutter
and signifincantly improve the readability of ip_input() and
ip_output() again.

The resulting IPSEC hooks in ip_input() and ip_output() may be
used later on for making IPSEC loadable.

This move is mostly mechanical and should preserve current IPSEC
behaviour as-is.  Nothing shall prevent improvements in the way
IPSEC interacts with the IPv4 stack.

Discussed with:	bz, gnn, rwatson; (earlier version)
2006-02-01 13:55:03 +00:00
Andre Oppermann
ab48768b20 When doing IP forwarding with [FAST_]IPSEC compiled into the kernel
ip_forward() would report back a zero MTU in ICMP needfrag messages
because on a IPSEC SP lookup failure no MTU got computed.

Fix this by changing the logic to compute a new MTU in any case if
IPSEC didn't do it.

Change MTU computation logic to use egress interface MTU if available
or the next smaller MTU compared to the current packet size instead
of falling back to a very small fixed MTU.

Fix associated comment.

PR:		kern/91412
MFC after:	3 days
2006-01-24 17:57:19 +00:00
Robert Watson
d248c7d7f5 Modify the IP fragment reassembly code so that it uses a new UMA zone,
ipq_zone, to allocate fragment headers from, rather than using cast mbuf
storage.  This was one of the few remaining uses of mbuf storage for
local data structures that relied on dtom().  Implement the resource
limit on ipq's using UMA zone limits, but preserve current sysctl
semantics using a sysctl proc.

MFC after:	3 weeks
2006-01-15 18:58:21 +00:00
Robert Watson
dfa60d9354 Staticize ipqlock, since it is local to ip_input.c.
MFC after:	3 days
2006-01-15 17:05:48 +00:00
Ruslan Ermilov
f4e9888107 Fix -Wundef. 2005-12-04 02:12:43 +00:00
Andre Oppermann
22f2c8b5db Remove 'ipprintfs' which were protected under DIAGNOSTIC. It doesn't
have any know to enable it from userland and could only be enabled by
either setting it to 1 at compile time or through the kernel debugger.

In the future it may be brought back as KTR tracing points.

Discussed with:	rwatson
Sponsored by:	TCP/IP Optimization Fundraise 2005
2005-11-19 17:04:52 +00:00
Andre Oppermann
ef39adf007 Consolidate all IP Options handling functions into ip_options.[ch] and
include ip_options.h into all files making use of IP Options functions.

From ip_input.c rev 1.306:
  ip_dooptions(struct mbuf *m, int pass)
  save_rte(m, option, dst)
  ip_srcroute(m0)
  ip_stripoptions(m, mopt)

From ip_output.c rev 1.249:
  ip_insertoptions(m, opt, phlen)
  ip_optcopy(ip, jp)
  ip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m)

No functional changes in this commit.

Discussed with:	rwatson
Sponsored by:	TCP/IP Optimization Fundraise 2005
2005-11-18 20:12:40 +00:00
Andre Oppermann
780b2f698c In ip_forward() copy as much into the temporary error mbuf as we
have free space in it.  Allocate correct mbuf from the beginning.
This allows icmp_error() to quote the entire TCP header in error
messages.

Sponsored by:	TCP/IP Optimization Fundraise 2005
2005-11-18 14:44:48 +00:00
Ruslan Ermilov
4a0d6638b3 - Store pointer to the link-level address right in "struct ifnet"
rather than in ifindex_table[]; all (except one) accesses are
  through ifp anyway.  IF_LLADDR() works faster, and all (except
  one) ifaddr_byindex() users were converted to use ifp->if_addr.

- Stop storing a (pointer to) Ethernet address in "struct arpcom",
  and drop the IFP2ENADDR() macro; all users have been converted
  to use IF_LLADDR() instead.
2005-11-11 16:04:59 +00:00
Andre Oppermann
e0aec68255 Use the correct mbuf type for MGET(). 2005-08-30 16:35:27 +00:00
Robert Watson
dd5a318ba3 Introduce in_multi_mtx, which will protect IPv4-layer multicast address
lists, as well as accessor macros.  For now, this is a recursive mutex
due code sequences where IPv4 multicast calls into IGMP calls into
ip_output(), which then tests for a multicast forwarding case.

For support macros in in_var.h to check multicast address lists, assert
that in_multi_mtx is held.

Acquire in_multi_mtx around iteration over the IPv4 multicast address
lists, such as in ip_input() and ip_output().

Acquire in_multi_mtx when manipulating the IPv4 layer multicast addresses,
as well as over the manipulation of ifnet multicast address lists in order
to keep the two layers in sync.

Lock down accesses to IPv4 multicast addresses in IGMP, or assert the
lock when performing IGMP join/leave events.

Eliminate spl's associated with IPv4 multicast addresses, portions of
IGMP that weren't previously expunged by IGMP locking.

Add in_multi_mtx, igmp_mtx, and if_addr_mtx lock order to hard-coded
lock order in WITNESS, in that order.

Problem reported by:	Ed Maste <emaste at phaedrus dot sandvine dot ca>
MFC after:		10 days
2005-08-03 19:29:47 +00:00
Robert Watson
b77634d046 Remove spl() calls from ip_slowtimo(), as IP fragment queue locking was
merged several years ago.

Submitted by:	gnn
MFC after:	1 day
2005-07-19 12:14:22 +00:00
Andre Oppermann
c773494edd Pass icmp_error() the MTU argument directly instead of
an interface pointer.  This simplifies a couple of uses
and removes some XXX workarounds.
2005-05-04 13:09:19 +00:00
Maxim Konovalov
800af1fb81 o Nano optimize ip_reass() code path for the first fragment: do not
try to reasseble the packet from the fragments queue with the only
fragment, finish with the first fragment as soon as we create a queue.

Spotted by:	Vijay Singh

o Drop the fragment if maxfragsperpacket == 0, no chances we
will be able to reassemble the packet in future.

Reviewed by:	silby
2005-04-08 10:25:13 +00:00
Sam Leffler
6a9909b5e6 plug resource leak
Noticed by:	Coverity Prevent analysis tool
2005-03-16 05:27:19 +00:00
Sam Leffler
db77984c5b fix potential invalid index into ip_protox array
Noticed by:	Coverity Prevent analysis tool
2005-02-23 00:38:12 +00:00
Andre Oppermann
099dd0430b Bring back the full packet destination manipulation for 'ipfw fwd'
with the kernel compile time option:

 options IPFIREWALL_FORWARD_EXTENDED

This option has to be specified in addition to IPFIRWALL_FORWARD.

With this option even packets targeted for an IP address local
to the host can be redirected.  All restrictions to ensure proper
behaviour for locally generated packets are turned off.  Firewall
rules have to be carefully crafted to make sure that things like
PMTU discovery do not break.

Document the two kernel options.

PR:		kern/71910
PR:		kern/73129
MFC after:	1 week
2005-02-22 17:40:40 +00:00
Gleb Smirnoff
a97719482d Add CARP (Common Address Redundancy Protocol), which allows multiple
hosts to share an IP address, providing high availability and load
balancing.

Original work on CARP done by Michael Shalayeff, with many
additions by Marco Pfatschbacher and Ryan McBride.

FreeBSD port done solely by Max Laier.

Patch by:	mlaier
Obtained from:	OpenBSD (mickey, mcbride)
2005-02-22 13:04:05 +00:00
Robert Watson
024105493d Prefer (NULL) spelling of (0) for pointers.
MFC after:	3 days
2005-01-30 19:29:47 +00:00
Warner Losh
c398230b64 /* -> /*- for license, minor formatting changes 2005-01-07 01:45:51 +00:00
Mike Silbersack
5f311da2cc Port randomization leads to extremely fast port reuse at high
connection rates, which is causing problems for some users.

To retain the security advantage of random ports and ensure
correct operation for high connection rate users, disable
port randomization during periods of high connection rates.

Whenever the connection rate exceeds randomcps (10 by default),
randomization will be disabled for randomtime (45 by default)
seconds.  These thresholds may be tuned via sysctl.

Many thanks to Igor Sysoev, who proved the necessity of this
change and tested many preliminary versions of the patch.

MFC After:	20 seconds
2005-01-02 01:50:57 +00:00
Andre Oppermann
de38924dc0 Support for dynamically loadable and unloadable IP protocols in the ipmux.
With pr_proto_register() it has become possible to dynamically load protocols
within the PF_INET domain.  However the PF_INET domain has a second important
structure called ip_protox[] that is derived from the 'struct protosw inetsw[]'
and takes care of the de-multiplexing of the various protocols that ride on
top of IP packets.

The functions ipproto_[un]register() allow to dynamically adjust the ip_protox[]
array mux in a consistent and easy way.  To register a protocol within
ip_protox[] the existence of a corresponding and matching protocol definition
in inetsw[] is required.  The function does not allow to overwrite an already
registered protocol.  The unregister function simply replaces the mux slot with
the default index pointer to IPPROTO_RAW as it was previously.
2004-10-19 15:45:57 +00:00
Max Laier
d6a8d58875 Add an additional struct inpcb * argument to pfil(9) in order to enable
passing along socket information. This is required to work around a LOR with
the socket code which results in an easy reproducible hard lockup with
debug.mpsafenet=1. This commit does *not* fix the LOR, but enables us to do
so later. The missing piece is to turn the filter locking into a leaf lock
and will follow in a seperate (later) commit.

This will hopefully be MT5'ed in order to fix the problem for RELENG_5 in
forseeable future.

Suggested by:		rwatson
A lot of work by:	csjp (he'd be even more helpful w/o mentor-reviews ;)
Reviewed by:		rwatson, csjp
Tested by:		-pf, -ipfw, LINT, csjp and myself
MFC after:		3 days

LOR IDs:		14 - 17 (not fixed yet)
2004-09-29 04:54:33 +00:00
Maxim Konovalov
4bc37f9836 o Turn net.inet.ip.check_interface sysctl off by default.
When net.inet.ip.check_interface was MFCed to RELENG_4 3+ years ago in
rev. 1.130.2.17 ip_input.c it was 1 by default but shortly changed to
0 (accidently?) in rev. 1.130.2.20 in RELENG_4 only.  Among with the
fact this knob is not documented it breaks POLA especially in bridge
environment.

OK'ed by:	andre
Reviewed by:	-current
2004-09-24 12:18:40 +00:00
Andre Oppermann
db09bef308 Fix an out of bounds write during the initialization of the PF_INET protocol
family to the ip_protox[] array.  The protocol number of IPPROTO_DIVERT is
larger than IPPROTO_MAX and was initializing memory beyond the array.
Catch all these kinds of errors by ignoring protocols that are higher than
IPPROTO_MAX or 0 (zero).

Add more comments ip_init().
2004-09-16 18:33:39 +00:00
Andre Oppermann
76ff6dcf46 Clarify some comments for the M_FASTFWD_OURS case in ip_input(). 2004-09-15 20:17:03 +00:00
Andre Oppermann
e098266191 Remove the last two global variables that are used to store packet state while
it travels through the IP stack.  This wasn't much of a problem because IP
source routing is disabled by default but when enabled together with SMP and
preemption it would have very likely cross-corrupted the IP options in transit.

The IP source route options of a packet are now stored in a mtag instead of the
global variable.
2004-09-15 20:13:26 +00:00
Andre Oppermann
c21fd23260 Always compile PFIL_HOOKS into the kernel and remove the associated kernel
compile option.  All FreeBSD packet filters now use the PFIL_HOOKS API and
thus it becomes a standard part of the network stack.

If no hooks are connected the entire packet filter hooks section and related
activities are jumped over.  This removes any performance impact if no hooks
are active.

Both OpenBSD and DragonFlyBSD have integrated PFIL_HOOKS permanently as well.
2004-08-27 15:16:24 +00:00
Andre Oppermann
e4c97eff8e Bring back the sysctl 'net.inet.ip.fw.enable' to unbreak the startup scripts
and to be able to disable ipfw if it was compiled directly into the kernel.
2004-08-19 17:38:47 +00:00
Robert Watson
0f48e25b63 Fix build of ip_input.c with "options IPSEC" -- the "pass:" label
is used with both FAST_IPSEC and IPSEC, but was defined for only
FAST_IPSEC.
2004-08-18 03:11:04 +00:00
Andre Oppermann
9b932e9e04 Convert ipfw to use PFIL_HOOKS. This is change is transparent to userland
and preserves the ipfw ABI.  The ipfw core packet inspection and filtering
functions have not been changed, only how ipfw is invoked is different.

However there are many changes how ipfw is and its add-on's are handled:

 In general ipfw is now called through the PFIL_HOOKS and most associated
 magic, that was in ip_input() or ip_output() previously, is now done in
 ipfw_check_[in|out]() in the ipfw PFIL handler.

 IPDIVERT is entirely handled within the ipfw PFIL handlers.  A packet to
 be diverted is checked if it is fragmented, if yes, ip_reass() gets in for
 reassembly.  If not, or all fragments arrived and the packet is complete,
 divert_packet is called directly.  For 'tee' no reassembly attempt is made
 and a copy of the packet is sent to the divert socket unmodified.  The
 original packet continues its way through ip_input/output().

 ipfw 'forward' is done via m_tag's.  The ipfw PFIL handlers tag the packet
 with the new destination sockaddr_in.  A check if the new destination is a
 local IP address is made and the m_flags are set appropriately.  ip_input()
 and ip_output() have some more work to do here.  For ip_input() the m_flags
 are checked and a packet for us is directly sent to the 'ours' section for
 further processing.  Destination changes on the input path are only tagged
 and the 'srcrt' flag to ip_forward() is set to disable destination checks
 and ICMP replies at this stage.  The tag is going to be handled on output.
 ip_output() again checks for m_flags and the 'ours' tag.  If found, the
 packet will be dropped back to the IP netisr where it is going to be picked
 up by ip_input() again and the directly sent to the 'ours' section.  When
 only the destination changes, the route's 'dst' is overwritten with the
 new destination from the forward m_tag.  Then it jumps back at the route
 lookup again and skips the firewall check because it has been marked with
 M_SKIP_FIREWALL.  ipfw 'forward' has to be compiled into the kernel with
 'option IPFIREWALL_FORWARD' to enable it.

 DUMMYNET is entirely handled within the ipfw PFIL handlers.  A packet for
 a dummynet pipe or queue is directly sent to dummynet_io().  Dummynet will
 then inject it back into ip_input/ip_output() after it has served its time.
 Dummynet packets are tagged and will continue from the next rule when they
 hit the ipfw PFIL handlers again after re-injection.

 BRIDGING and IPFW_ETHER are not changed yet and use ipfw_chk() directly as
 they did before.  Later this will be changed to dedicated ETHER PFIL_HOOKS.

More detailed changes to the code:

 conf/files
	Add netinet/ip_fw_pfil.c.

 conf/options
	Add IPFIREWALL_FORWARD option.

 modules/ipfw/Makefile
	Add ip_fw_pfil.c.

 net/bridge.c
	Disable PFIL_HOOKS if ipfw for bridging is active.  Bridging ipfw
	is still directly invoked to handle layer2 headers and packets would
	get a double ipfw when run through PFIL_HOOKS as well.

 netinet/ip_divert.c
	Removed divert_clone() function.  It is no longer used.

 netinet/ip_dummynet.[ch]
	Neither the route 'ro' nor the destination 'dst' need to be stored
	while in dummynet transit.  Structure members and associated macros
	are removed.

 netinet/ip_fastfwd.c
	Removed all direct ipfw handling code and replace it with the new
	'ipfw forward' handling code.

 netinet/ip_fw.h
	Removed 'ro' and 'dst' from struct ip_fw_args.

 netinet/ip_fw2.c
	(Re)moved some global variables and the module handling.

 netinet/ip_fw_pfil.c
	New file containing the ipfw PFIL handlers and module initialization.

 netinet/ip_input.c
	Removed all direct ipfw handling code and replace it with the new
	'ipfw forward' handling code.  ip_forward() does not longer require
	the 'next_hop' struct sockaddr_in argument.  Disable early checks
	if 'srcrt' is set.

 netinet/ip_output.c
	Removed all direct ipfw handling code and replace it with the new
	'ipfw forward' handling code.

 netinet/ip_var.h
	Add ip_reass() as general function.  (Used from ipfw PFIL handlers
	for IPDIVERT.)

 netinet/raw_ip.c
	Directly check if ipfw and dummynet control pointers are active.

 netinet/tcp_input.c
	Rework the 'ipfw forward' to local code to work with the new way of
	forward tags.

 netinet/tcp_sack.c
	Remove include 'opt_ipfw.h' which is not needed here.

 sys/mbuf.h
	Remove m_claim_next() macro which was exclusively for ipfw 'forward'
	and is no longer needed.

Approved by:	re (scottl)
2004-08-17 22:05:54 +00:00
David Malone
1f44b0a1b5 Get rid of the RANDOM_IP_ID option and make it a sysctl. NetBSD
have already done this, so I have styled the patch on their work:

        1) introduce a ip_newid() static inline function that checks
        the sysctl and then decides if it should return a sequential
        or random IP ID.

        2) named the sysctl net.inet.ip.random_id

        3) IPv6 flow IDs and fragment IDs are now always random.
        Flow IDs and frag IDs are significantly less common in the
        IPv6 world (ie. rarely generated per-packet), so there should
        be smaller performance concerns.

The sysctl defaults to 0 (sequential IP IDs).

Reviewed by:	andre, silby, mlaier, ume
Based on:	NetBSD
MFC after:	2 months
2004-08-14 15:32:40 +00:00
Andre Oppermann
9d804f818c Fix two cases of incorrect IPQ_UNLOCK'ing in the merged ip_reass() function.
The first one was going to 'dropfrag', which unlocks the IPQ, before the lock
was aquired; The second one doing a unlock and then a 'goto dropfrag' which
led to a double-unlock.

Tripped over by:	des
2004-08-12 08:37:42 +00:00
Andre Oppermann
0b17fba7bc Consistently use NULL for pointer comparisons. 2004-08-11 10:46:15 +00:00
Andre Oppermann
bb7c5b3055 Make a comment that IP source routing is not SMP and PREEMPTION safe. 2004-08-09 16:17:37 +00:00
Andre Oppermann
f0cada84b1 o Move all parts of the IP reassembly process into the function ip_reass() to
make it fully self-contained.
o ip_reass() now returns a new mbuf with the reassembled packet and ip->ip_len
  including the IP header.
o Computation of the delayed checksum is moved into divert_packet().

Reviewed by:	silby
2004-08-03 12:31:38 +00:00
Brian Somers
0ac4013324 Change the following environment variables to kernel options:
bootp -> BOOTP
    bootp.nfsroot -> BOOTP_NFSROOT
    bootp.nfsv3 -> BOOTP_NFSV3
    bootp.compat -> BOOTP_COMPAT
    bootp.wired_to -> BOOTP_WIRED_TO

- i.e. back out the previous commit.  It's already possible to
pxeboot(8) with a GENERIC kernel.

Pointed out by: dwmalone
2004-07-08 22:35:36 +00:00
Brian Somers
59e1ebc9b5 Change the following kernel options to environment variables:
BOOTP -> bootp
    BOOTP_NFSROOT -> bootp.nfsroot
    BOOTP_NFSV3 -> bootp.nfsv3
    BOOTP_COMPAT -> bootp.compat
    BOOTP_WIRED_TO -> bootp.wired_to

This lets you PXE boot with a GENERIC kernel by putting this sort of thing
in loader.conf:

    bootp="YES"
    bootp.nfsroot="YES"
    bootp.nfsv3="YES"
    bootp.wired_to="bge1"

or even setting the variables manually from the OK prompt.
2004-07-08 13:40:33 +00:00
Bruce M Simpson
4f450ff9a5 Check that m->m_pkthdr.rcvif is not NULL before checking if a packet
was received on a broadcast address on the input path. Under certain
circumstances this could result in a panic, notably for locally-generated
packets which do not have m_pkthdr.rcvif set.

This is a similar situation to that which is solved by
src/sys/netinet/ip_icmp.c rev 1.66.

PR:		kern/52935
2004-06-18 12:58:45 +00:00
Bruce M Simpson
57ab3660ff In ip_forward(), when calculating the MTU in effect for an IPSEC transport
mode tunnel, take the per-route MTU into account, *if* and *only if* it
is non-zero (as found in struct rt_metrics/rt_metrics_lite).

PR:		kern/42727
Obtained from:	NetBSD (ip_input.c rev 1.151)
2004-06-16 08:33:09 +00:00
Bruce M Simpson
e6b0a57025 In ip_forward(), set m->m_pkthdr.len correctly such that the mbuf chain
is sane, and ipsec4_getpolicybyaddr() will therefore complete.

PR:		kern/42727
Obtained from:	KAME (kame/freebsd4/sys/netinet/ip_input.c rev 1.42)
2004-06-16 08:28:54 +00:00