netfilter: x_tables: use correct integer types

Sparse complains because __be32 and u32 are mixed without
conversions. Use the correct types, no code changes.

Furthermore, xt_DSCP generates a bit truncation warning:
"cast truncates bits from constant value (ffffff03 becomes 3)"

The truncation is fine (and wanted). Add a private definition and use that
instead.

objdiff shows no changes.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

netfilter: tcpmss, optstrip: prefer skb_ensure_writable

This also changes optstrip to only make the tcp header writeable
rather than the entire packet.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: x_tables: use pr ratelimiting in all remaining spots

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: move route indirection to struct nf_ipv6_ops

We cannot make a direct call to nf_ip6_route() because that would result
in autoloading the 'ipv6' module because of symbol dependencies.
Therefore, define route indirection in nf_ipv6_ops where this really
belongs to.

For IPv4, we can indeed make a direct function call, which is faster,
given IPv4 is built-in in the networking code by default. Still,
CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline
stub for IPv4 in such case.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Remove duplicated rcu_read_lock.

This patch removes duplicate rcu_read_lock().

1. IPVS part:

According to Julian Anastasov's mention, contexts of ipvs are described
at: http://marc.info/?l=netfilter-devel&m=149562884514072&w=2, in summary:

- packet RX/TX: does not need locks because packets come from hooks.
- sync msg RX: backup server uses RCU locks while registering new
connections.
- ip_vs_ctl.c: configuration get/set, RCU locks needed.
- xt_ipvs.c: It is a netfilter match, running from hook context.

As result, rcu_read_lock and rcu_read_unlock can be removed from:

- ip_vs_core.c: all
- ip_vs_ctl.c:
- only from ip_vs_has_real_service
- ip_vs_ftp.c: all
- ip_vs_proto_sctp.c: all
- ip_vs_proto_tcp.c: all
- ip_vs_proto_udp.c: all
- ip_vs_xmit.c: all (contains only packet processing)

2. Netfilter part:

There are three types of functions that are guaranteed the rcu_read_lock().
First, as result, functions are only called by nf_hook():

- nf_conntrack_broadcast_help(), pptp_expectfn(), set_expected_rtp_rtcp().
- tcpmss_reverse_mtu(), tproxy_laddr4(), tproxy_laddr6().
- match_lookup_rt6(), check_hlist(), hashlimit_mt_common().
- xt_osf_match_packet().

Second, functions that caller already held the rcu_read_lock().
- destroy_conntrack(), ctnetlink_conntrack_event().
- ctnl_timeout_find_get(), nfqnl_nf_hook_drop().

Third, functions that are mixed with type1 and type2.

These functions are called by nf_hook() also these are called by
ordinary functions that already held the rcu_read_lock():

- __ctnetlink_glue_build(), ctnetlink_expect_event().
- ctnetlink_proto_size().

Applied files are below:

- nf_conntrack_broadcast.c, nf_conntrack_core.c, nf_conntrack_netlink.c.
- nf_conntrack_pptp.c, nf_conntrack_sip.c, nfnetlink_cttimeout.c.
- nfnetlink_queue.c, xt_TCPMSS.c, xt_TPROXY.c, xt_addrtype.c.
- xt_connlimit.c, xt_hashlimit.c, xt_osf.c

Detailed calltrace can be found at:
http://marc.info/?l=netfilter-devel&m=149667610710350&w=2

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: add more sanity tests on tcph->doff

Denys provided an awesome KASAN report pointing to an use
after free in xt_TCPMSS

I have provided three patches to fix this issue, either in xt_TCPMSS or
in xt_tcpudp.c. It seems xt_TCPMSS patch has the smallest possible
impact.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: x_tables: move hook state into xt_action_param structure

Place pointer to hook state in xt_action_param structure instead of
copying the fields that we need. After this change xt_action_param fits
into one cacheline.

This patch also adds a set of new wrapper functions to fetch relevant
hook state structure fields.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: Refactor the codes to decrease one condition check and more readable

The origin codes perform two condition checks with dst_mtu(skb_dst(skb))
and in_mtu. And the last statement is "min(dst_mtu(skb_dst(skb)),
in_mtu) - minlen". It may let reader think about how about the result.
Would it be negative.

Now assign the result of min(dst_mtu(skb_dst(skb)), in_mtu) to a new
variable, then only perform one condition check, and it is more readable.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: handle CHECKSUM_COMPLETE in tcpmss_tg6()

In case MSS option is added in TCP options, skb length increases by 4.
IPv6 needs to update skb->csum if skb has CHECKSUM_COMPLETE,
otherwise kernel complains loudly in netdev_rx_csum_fault() with a
stack dump.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: x_tables: Use par->net instead of computing from the passed net devices

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: Change pseudohdr argument of inet_proto_csum_replace* to be a bool

inet_proto_csum_replace4,2,16 take a pseudohdr argument which indicates
the checksum field carries a pseudo header. This argument should be a
boolean instead of an int.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: x_tables: add context to know if extension runs from nft_compat

Currently, we have four xtables extensions that cannot be used from the
xt over nft compat layer. The problem is that they need real access to
the full blown xt_entry to validate that the rule comes with the right
dependencies. This check was introduced to overcome the lack of
sufficient userspace dependency validation in iptables.

To resolve this problem, this patch introduces a new field to the
xt_tgchk_param structure that tell us if the extension is run from
nft_compat context.

The three affected extensions are:

1) CLUSTERIP, this target has been superseded by xt_cluster. So just
bail out by returning -EINVAL.

2) TCPMSS. Relax the checking when used from nft_compat. If used with
the wrong configuration, it will corrupt !syn packets by adding TCP
MSS option.

3) ebt_stp. Relax the check to make sure it uses the reserved
destination MAC address for STP.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Tested-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>

netfilter: xt_TCPMSS: lookup route from proper net namespace

Otherwise the pmtu will be incorrect.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: Get mtu only if clamp-mss-to-pmtu is specified

This patch refactors the code to skip tcpmss_reverse_mtu if no
clamp-mss-to-pmtu is specified.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: correct return value in tcpmss_mangle_packet

In commit b396966c4 (netfilter: xt_TCPMSS: Fix missing fragmentation handling),
I attempted to add safe fragment handling to xt_TCPMSS. However, Andy Padavan
of Project N56U correctly points out that returning XT_CONTINUE in this
function does not work. The callers (tcpmss_tg[46]) expect to receive a value
of 0 in order to return XT_CONTINUE.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: fix handling of malformed TCP header and options

Make sure the packet has enough room for the TCP header and
that it is not malformed.

While at it, store tcph->doff*4 in a variable, as it is used
several times.

This patch also fixes a possible off by one in case of malformed
TCP options.

Reported-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: Fix missing fragmentation handling

Similar to commit bc6bcb59 ("netfilter: xt_TCPOPTSTRIP: fix
possible mangling beyond packet boundary"), add safe fragment
handling to xt_TCPMSS.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: Fix IPv6 default MSS too

As a followup to commit 409b545a ("netfilter: xt_TCPMSS: Fix violation
of RFC879 in absence of MSS option"), John Heffner points out that IPv6
has a higher MTU than IPv4, and thus a higher minimum MSS. Update TCPMSS
target to account for this, and update RFC comment.

While at it, point to more recent reference RFC1122 instead of RFC879.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: xt_TCPMSS: Fix violation of RFC879 in absence of MSS option

The clamp-mss-to-pmtu option of the xt_TCPMSS target can cause issues
connecting to websites if there was no MSS option present in the
original SYN packet from the client. In these cases, it may add a
MSS higher than the default specified in RFC879. Fix this by never
setting a value > 536 if no MSS option was specified by the client.

This closes netfilter's bugzilla #662.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add my copyright statements

Add copyright statements to all netfilter files which have had significant
changes done by myself in the past.

Some notes:

- nf_conntrack_ecache.c was incorrectly attributed to Rusty and Netfilter
Core Team when it got split out of nf_conntrack_core.c. The copyrights
even state a date which lies six years before it was written. It was
written in 2005 by Harald and myself.

- net/ipv{4,6}/netfilter.c, net/netfitler/nf_queue.c were missing copyright
statements. I've added the copyright statement from net/netfilter/core.c,
where this code originated

- for nf_conntrack_proto_tcp.c I've also added Jozsef, since I didn't want
it to give the wrong impression

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: Convert net_ratelimit uses to net_<level>_ratelimited

Standardize the net core ratelimited logging functions.

Coalesce formats, align arguments.
Change a printk then vprintk sequence to use printf extension %pV.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net:netfilter: use IS_ENABLED

Use IS_ENABLED(CONFIG_FOO)
instead of defined(CONFIG_FOO) || defined (CONFIG_FOO_MODULE)

Signed-off-by: Igor Maravić <igorm@etf.rs>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Add fragment reporting to ipv6_skip_exthdr().

While parsing through IPv6 extension headers, fragment headers are
skipped making them invisible to the caller. This reports the
fragment offset of the last header in order to make it possible to
determine whether the packet is fragmented and, if so whether it is
a first or last fragment.

Signed-off-by: Jesse Gross <jesse@nicira.com>

net: remove ipv6_addr_copy()

C assignment can handle struct in6_addr copying.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: af_info: add 'strict' parameter to limit lookup to .oif

ipv6 fib lookup can set RT6_LOOKUP_F_IFACE flag to restrict search
to an interface, but this flag cannot be set via struct flowi.

Also, it cannot be set via ip6_route_output: this function uses the
passed sock struct to determine if this flag is required
(by testing for nonzero sk_bound_dev_if).

Work around this by passing in an artificial struct sk in case
'strict' argument is true.

This is required to replace the rt6_lookup call in xt_addrtype.c with
nf_afinfo->route().

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: af_info: add network namespace parameter to route hook

This is required to eventually replace the rt6_lookup call in
xt_addrtype.c with nf_afinfo->route().

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: Use flowi4 and flowi6 in xt_TCPMSS

Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: unify tcp flag macros

unify tcp flag macros: TCPHDR_FIN, TCPHDR_SYN, TCPHDR_RST, TCPHDR_PSH,
TCPHDR_ACK, TCPHDR_URG, TCPHDR_ECE and TCPHDR_CWR. TCBCB_FLAG_* are replaced
with the corresponding TCPHDR_*.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
----
include/net/tcp.h | 24 ++++++-------
net/ipv4/tcp.c | 8 ++--
net/ipv4/tcp_input.c | 2 -
net/ipv4/tcp_output.c | 59 ++++++++++++++++-----------------
net/netfilter/nf_conntrack_proto_tcp.c | 32 ++++++-----------
net/netfilter/xt_TCPMSS.c | 4 --
6 files changed, 58 insertions(+), 71 deletions(-)
Signed-off-by: David S. Miller <davem@davemloft.net>

net-next: remove useless union keyword

remove useless union keyword in rtable, rt6_info and dn_route.

Since there is only one member in a union, the union keyword isn't useful.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: xtables: substitute temporary defines by final name

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

netfilter: xtables: change targets to return error code

Part of the transition of done by this semantic patch:
// <smpl>
@ rule1 @
struct xt_target ops;
identifier check;
@@
ops.checkentry = check;

@@
identifier rule1.check;
@@
check(...) { <...
-return true;
+return 0;
...> }

@@
identifier rule1.check;
@@
check(...) { <...
-return false;
+return -EINVAL;
...> }
// </smpl>

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

netfilter: xtables: change xt_target.checkentry return type

Restore function signatures from bool to int so that we can report
memory allocation failures or similar using -ENOMEM rather than
always having to pass -EINVAL back.

// <smpl>
@@
type bool;
identifier check, par;
@@
-bool check
+int check
(struct xt_tgchk_param *par) { ... }
// </smpl>

Minus the change it does to xt_ct_find_proto.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

netfilter: xt extensions: use pr_<level> (2)

Supplement to 1159683ef48469de71dc26f0ee1a9c30d131cf89.

Downgrade the log level to INFO for most checkentry messages as they
are, IMO, just an extra information to the -EINVAL code that is
returned as part of a parameter "constraint violation". Leave errors
to real errors, such as being unable to create a LED trigger.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

netfilter: xt extensions: use pr_<level>

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

netfilter: xtables: replace XT_MATCH_ITERATE macro

The macro is replaced by a list.h-like foreach loop. This makes
the code more inspectable.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: xt_TCPMSS: SYN packets are allowed to contain data

The TCPMSS target is dropping SYN packets where:
1) There is data, or
2) The data offset makes the TCP header larger than the packet.

Both of these result in an error level printk. This printk has been
removed.

This change avoids dropping SYN packets containing data. If there
is also no MSS option (as well as data), one will not be added
because of possible complications due to the increased packet size.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Patrick McHardy <kaber@trash.net>

net: skb->dst accessors

Define three accessors to get/set dst attached to a skb

struct dst_entry *skb_dst(const struct sk_buff *skb)

void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)

void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;

Delete skb->dst field

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: xtables: move extension arguments into compound structure (5/6)

This patch does this for target extensions' checkentry functions.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: xtables: move extension arguments into compound structure (4/6)

This patch does this for target extensions' target functions.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: x_tables: use NFPROTO_* in extensions

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: xt_TCPMSS: collapse tcpmss_reverse_mtu{4,6} into one function

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: xt_TCPMSS: consider reverse route's MTU in clamp-to-pmtu

The TCPMSS target in Xtables should consider the MTU of the reverse
route on forwarded packets as part of the path MTU.

Point in case: IN=ppp0, OUT=eth0. MSS set to 1460 in spite of MTU of
ppp0 being 1392.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Update modules' descriptions

Updates the MODULE_DESCRIPTION() tags for all Netfilter modules,
actually describing what the module does and not just
"netfilter XYZ target".

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: xt_TCPMSS: don't allow netfilter --setmss to increase mss

When terminating DSL connections for an assortment of random customers, I've
found it necessary to use iptables to clamp the MSS used for connections to
work around the various ICMP blackholes in the greater net. Unfortunately,
the current behaviour in Linux is imperfect and actually make things worse,
so I'm proposing the following: increasing the MSS in a packet can never be
a good thing, so make --set-mss only lower the MSS in a packet.

Yes, I am aware of --clamp-mss-to-pmtu, but it doesn't work for outgoing
connections from clients (ie web traffic), as it only looks at the PMTU on
the destination route, not the source of the packet (the DSL interfaces in
question have a 1442 byte MTU while the destination ethernet interface is
1500 -- there are problematic hosts which use a 1300 byte MTU). Reworking
that is probably a good idea at some point, but it's more work than this is.

Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: x_tables: consistent and unique symbol names

Give all Netfilter modules consistent and unique symbol names.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Convert old checksum helper names

Kill the defines again, convert to the new checksum helper names and
remove the dependency of NET_ACT_NAT on NETFILTER.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Introduce NF_INET_ hook values

The IPv4 and IPv6 hook values are identical, yet some code tries to figure
out the "correct" value by looking at the address family. Introduce NF_INET_*
values for both IPv4 and IPv6. The old values are kept in a #ifndef __KERNEL__
section for userspace compatibility.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: xt_TCPMSS: remove network triggerable WARN_ON

ipv6_skip_exthdr() returns -1 for invalid packets. don't WARN_ON
that.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

[NETFILTER]: Replace sk_buff ** with sk_buff *

With all the users of the double pointers removed, this patch mops up by
finally replacing all occurances of sk_buff ** in the netfilter API by
sk_buff *.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Avoid skb_copy/pskb_copy/skb_realloc_headroom

This patch replaces unnecessary uses of skb_copy, pskb_copy and
skb_realloc_headroom by functions such as skb_make_writable and
pskb_expand_head.

This allows us to remove the double pointers later.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Do not copy skb in skb_make_writable

Now that all callers of netfilter can guarantee that the skb is not shared,
we no longer have to copy the skb in skb_make_writable.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: x_tables: mark matches and targets __read_mostly

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Remove redundant parentheses/braces

Removes redundant parentheses and braces (And add one pair in a
xt_tcpudp.c macro).

Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: x_tables: switch xt_target->checkentry to bool

Switch the return type of target checkentry functions to boolean.

Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[SK_BUFF]: Introduce ipv6_hdr(), remove skb->nh.ipv6h

Now the skb->nh union has just one member, .raw, i.e. it is just like the
skb->mac union, strange, no? I'm just leaving it like that till the transport
layer is done with, when we'll rename skb->mac.raw to skb->mac_header (or
->mac_header_offset?), ditto for ->{h,nh}.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[SK_BUFF]: Introduce ip_hdr(), remove skb->nh.iph

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[SK_BUFF]: Introduce skb_network_header()

For the places where we need a pointer to the network header, it is still legal
to touch skb->nh.raw directly if just adding to, subtracting from or setting it
to another layer header.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: add IPv6-capable TCPMSS target

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>