Handle non-linear skbs by linearizing them instead of silently failing.
Long term the helper should be fixed to either work with non-linear skbs
directly by using the string search API or work on a copy of the data.

Based on patch by Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Make sure all printk messages have a severity level.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
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>

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

Add support for mangling TCP SIP packets.
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>

In particular, several occurances of funny versions of 'success',
'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address',
'beginning', 'desirable', 'separate' and 'necessary' are fixed.
Signed-off-by: NDaniel Mack <daniel@caiaq.de>
Cc: Joe Perches <joe@perches.com>
Cc: Junio C Hamano <gitster@pobox.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

In a string like "v:SIP/2.0..." it was checking for !isalpha('S') when it
meant to be inspecting the ':'.

Patch by Greg Alexander <greqcs@galexander.org>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

This patch adds the macro MODULE_ALIAS_NFCT_HELPER that defines a
way to provide generic and persistent aliases for the connection
tracking helpers.

This next patch requires this patch.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Make per-netns a) expectation hash and b) expectations count.

Expectations always belongs to netns to which it's master conntrack belong.
This is natural and doesn't bloat expectation.

Proc files and leaf users are stubbed to init_net, this is temporary.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Helper's ->help hook can run concurrently with itself, so iterating over
SIP helpers with static pointer won't work reliably.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some Inovaphone PBXs exhibit very stange behaviour: when dialing for
example "123", the device sends INVITE requests for "1", "12" and
"123" back to back.  The first requests will elicit error responses
from the receiver, causing the SIP helper to flush the RTP
expectations even though we might still see a positive response.

Note the sequence number of the last INVITE request that contained a
media description and only flush the expectations when receiving a
negative response for that sequence number.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reported by Ingo Molnar.

The SIP helper is also useful without NAT. This patch adds an ifdef
around the RTP call optimization for NATed clients.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add accessors for l3num and protonum and get rid of some overly long
expressions.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Some callers pass uninitialized structures, clear the address to make
sure later comparisions work properly.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

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

Optimize call routing between NATed endpoints: when an external
registrar sends a media description that contains an existing RTP
expectation from a different SNATed connection, the gatekeeper
is trying to route the call directly between the two endpoints.

We assume both endpoints can reach each other directly and
"un-NAT" the addresses, which makes the media stream go between
the two endpoints directly.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for multiple media channels and use it to create
expectations for video streams when present.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The SDP connection addresses may be contained in the payload multiple
times (in the session description and/or once per media description),
currently only the session description is properly updated. Split up
SDP mangling so the function setting up expectations only updates the
media port, update connection addresses from media descriptions while
parsing them and at the end update the session description when the
final addresses are known.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Create expectations for the RTCP connections in addition to RTP connections.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Media streams can come from anywhere, add a module parameter which
controls whether wildcard expectations or expectations between the
two signalling endpoints are created.

Since the same media description sent on multiple connections may
results in multiple identical expections when using a wildcard source,
we need to check whether a similar expectation already exists for a
different connection before attempting to register it.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Create expectations for incoming signalling connections when seeing
a REGISTER request. This is needed when the registrar uses a
different source port number for signalling messages and for receiving
incoming calls from other endpoints than the registrar.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce URI and header parameter parsing helpers. These are needed
by the conntrack helper to parse expiration values in Contact: header
parameters and by the NAT helper to properly update the Via-header
rport=, received= and maddr= parameters.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Flush the RTP expectations we've created when a call is hung up or
terminated otherwise.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Both may contains SDP offers/answers.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Perform NAT last after parsing the packet. This makes no difference
currently, but is needed when dealing with registrations to make
sure we seen the unNATed addresses.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for per-method request/response handlers and perform SDP
parsing for INVITE/UPDATE requests and for all informational and
successful responses.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

Use the URI parsing helper to get the numerical addresses and get rid of the
text based header translation.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce a helper function to parse a SIP-URI in a header value, optionally
iterating through all headers of this kind.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce new function for SIP header parsing that properly deals with
continuation lines and whitespace in headers and use it.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The request URI is not a header and needs to be treated differently than
real SIP headers. Add a seperate function for parsing it and get rid of
the POS_REQ_URI/POS_REG_REQ_URI definitions.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SDP and SIP headers are quite different, SIP can have continuation lines,
leading and trailing whitespace after the colon and is mostly case-insensitive
while SDP headers always begin on a new line and are followed by an equal
sign and the value, without any whitespace.

Introduce new SDP header parsing function and convert all users that used
the SIP header parsing function. This will allow to properly deal with the
special SIP cases in the SIP header parsing function later.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace sizeof/memcmp by strlen/strcmp. Use case-insensitive comparison
for SIP methods and the SIP/2.0 string, as specified in RFC 3261.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The conntrack reference and ctinfo can be derived from the packet.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After mangling the packet, the pointer to the data and the length of the data
portion may change and need to be adjusted.

Use double data pointers and a pointer to the length everywhere and add a
helper function to the NAT helper for performing the adjustments.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>