ebtables can be compiled to perform userspace-side padding of
structures. In that case, all the structures are already in the
'native' format expected by the kernel.

This tries to determine what format the userspace program is
using.

For most set/getsockopts, this can be done by checking
the len argument for sizeof(compat_ebt_replace) and
re-trying the native handler on error.

In case of EBT_SO_GET_ENTRIES, the native handler is tried first,
it will error out early when checking the *len argument
(the compat version has to defer this check until after
 iterating over the kernel data set once, to adjust for all
 the structure size differences).

As this would cause error printks, remove those as well, as
recommended by Bart de Schuymer.
Signed-off-by: NFlorian Westphal <fw@strlen.de>

Main code for 32 bit userland ebtables binary with 64 bit kernels
support.

Tested on x86_64 kernel only, using 64bit ebtables binary
for output comparision.

At least ebt_mark, m_mark and ebt_limit need CONFIG_COMPAT hooks, too.

remaining problem:

The ebtables userland makefile has:
ifeq ($(shell uname -m),sparc64)
	CFLAGS+=-DEBT_MIN_ALIGN=8 -DKERNEL_64_USERSPACE_32
endif

struct ebt_replace, ebt_entry_match etc. then contain userland-side
padding, i.e.  even if we are called from a 32 bit userland, the
structures may already be in the right format.

This problem is addressed in a follow-up patch.
Signed-off-by: NFlorian Westphal <fwestphal@astaro.com>

allows to call do_update_counters() from upcoming CONFIG_COMPAT
code instead of copy&pasting the same code.
Signed-off-by: NFlorian Westphal <fw@strlen.de>

once CONFIG_COMPAT support is added to ebtables, the new
copy_counters_to_user function can be called instead of duplicating
code.

Also remove last use of MEMPRINT, as requested by Bart De Schuymer.
Signed-off-by: NFlorian Westphal <fw@strlen.de>

once CONFIG_COMPAT support is merged this allows
to call do_replace_finish() after doing the CONFIG_COMPAT conversion
instead of copy & pasting this.
Signed-off-by: NFlorian Westphal <fw@strlen.de>

with 32 bit userland and 64 bit kernels, it is unlikely but possible
that insertion of new rules fails even tough there are only about 2000
iptables rules.

This happens because the compat delta is using a short int.
Easily reproducible via "iptables -m limit" ; after about 2050
rules inserting new ones fails with -ELOOP.

Note that compat_delta included 2 bytes of padding on x86_64, so
structure size remains the same.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

This will cause trouble once CONFIG_COMPAT support is added to ebtables.
xt_compat_*_offset() calculate the kernel/userland structure size delta
using:

XT_ALIGN(size) - COMPAT_XT_ALIGN(size)

If the match/target sizes are aligned at registration time,
delta is always zero.

Should have zero effect for existing systems: xtables uses
XT_ALIGN() whenever it deals with match/target sizes.
Signed-off-by: NFlorian Westphal <fwestphal@astaro.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

next_offset must be > 0, otherwise this loops forever.
The offset also contains the size of the ebt_entry structure
itself, so anything smaller is invalid.
Signed-off-by: NFlorian Westphal <fwestphal@astaro.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Parse and dump the conntrack zone in ctnetlink.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Normally, each connection needs a unique identity. Conntrack zones allow
to specify a numerical zone using the CT target, connections in different
zones can use the same identity.

Example:

iptables -t raw -A PREROUTING -i veth0 -j CT --zone 1
iptables -t raw -A OUTPUT -o veth1 -j CT --zone 1
Signed-off-by: NPatrick McHardy <kaber@trash.net>

The error handlers might need the template to get the conntrack zone
introduced in the next patches to perform a conntrack lookup.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

This should make it easier to remove redundant arguments later.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

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

Print which revision has been used and which size are which
(kernel/user) for easier debugging.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

GCC is now smart enough to follow the inline trail correctly.
vmlinux size remain the same.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

No changes in vmlinux filesize.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

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

It is one of these things that iptables cannot catch and which can
cause "Invalid argument" to be printed. Without a hint in dmesg, it is
not going to be helpful.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

call_rcu() will unconditionally reinitialize RCU head anyway.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Remove #ifdef at nf_ct_exp_net() by using nf_ct_net().
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

In POST_ROUTING hook, calling dev_net(in) is going to oops.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NPatrick McHardy <kaber@trash.net>

Add support for mangling TCP SIP packets.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

nf_nat_mangle_tcp_packet() can currently only handle a single mangling
per window because it only maintains two sequence adjustment positions:
the one before the last adjustment and the one after.

This patch makes sequence number adjustment tracking in
nf_nat_mangle_tcp_packet() optional and allows a helper to manually
update the offsets after the packet has been fully handled.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Add TCP support, which is mandated by RFC3261 for all SIP elements.

SIP over TCP is similar to UDP, except that messages are delimited
by Content-Length: headers and multiple messages may appear in one
packet.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

When using TCP multiple SIP messages might be present in a single packet.
A following patch will parse them by setting the dptr to the beginning of
each message. The NAT helper needs to reload the dptr value after mangling
the packet however, so it needs to know the offset of the message to the
beginning of the packet.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

When requests are parsed, the "sip:" part of the SIP URI should be skipped.

Usually this doesn't matter because address parsing skips forward until after
the username part, but in case REGISTER requests it doesn't contain a username
and the address can not be parsed.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Make the output a bit more informative by showing the helper an expectation
belongs to and the expectation class.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NPatrick McHardy <kaber@trash.net>

The static initial tables are pretty large, and after the net
namespace has been instantiated, they just hang around for nothing.
This commit removes them and creates tables on-demand at runtime when
needed.

Size shrinks by 7735 bytes (x86_64).
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

The respective xt_table structures already have most of the metadata
needed for hook setup. Add a 'priority' field to struct xt_table so
that xt_hook_link() can be called with a reduced number of arguments.

So should we be having more tables in the future, it comes at no
static cost (only runtime, as before) - space saved:
6807373->6806555.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

The calls to ip6t_do_table only show minimal differences, so it seems
like a good cleanup to merge them to a single one too.
Space saving obtained by both patches: 6807725->6807373
("Total" column from `size -A`.)
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

This patch combines all the per-hook functions in a given table into
a single function. Together with the 2nd patch, further
simplifications are possible up to the point of output code reduction.
Signed-off-by: NJan Engelhardt <jengelh@medozas.de>

Signed-off-by: NPatrick McHardy <kaber@trash.net>

Rewrite COMPAT_XT_ALIGN in terms of dummy structure hack.
Compat counters logically have nothing to do with it.
Use ALIGN() macro while I'm at it for same types.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

There is compat_u64 type which deals with different u64 type alignment
on different compat-capable platforms, so use it and removed some
hardcoded assumptions.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NPatrick McHardy <kaber@trash.net>