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

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

We need to set up the destination NAT mapping before the source NAT
mapping, so the NAT core gets to see the final tuple and can decide
whether the source port needs to be remapped.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

nf_nat_setup_info gets the hook number and translates that to the
manip type to perform. This is a relict from the time when one
manip per hook could exist, the exact hook number doesn't matter
anymore, its converted to the manip type. Most callers already
know what kind of NAT they want to perform, so pass the maniptype
in directly.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

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

As noticed by Paul McKenney, the rcu_dereference calls in the init path
of NAT modules are unneeded, remove them.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

Don't drop packets shorter than "SIP/2.0", just ignore them. Keep-alives
can validly be shorter for example.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Convert DEBUGP to pr_debug and fix lots of non-compiling debug statements.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently there is a wild mix of nf_conntrack_expect_, nf_ct_exp_,
expect_, exp_, ...

Consistently use nf_ct_ as prefix for exported functions.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

DNAT of the the RTP session is only necessary if the SIP session has
been SNATed.
Signed-off-by: Jerome Borsboom <j.borsboom@erasmusmc.nl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

I needed to use this recently to talk to a Cisco server.  In my case
I only did SNAT while the Cisco server used a different address for
RTP traffic than the one for SIP.  I discovered that nf_nat_sip NATed
the RTP address to the SIP one which was unnecessary but OK.  However,
in doing so it did not DNAT the destination address on the RTP traffic
to the Cisco back to the original RTP address.

This patch corrects this by noting down the RTP address and using it
when the expectation fires.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

For the common sequence "skb->nh.iph->ihl * 4", removing a good number of open
coded skb->nh.iph uses, now to go after the rest...

Just out of curiosity, here are the idioms found to get the same result:

skb->nh.iph->ihl << 2
skb->nh.iph->ihl<<2
skb->nh.iph->ihl * 4
skb->nh.iph->ihl*4
(skb->nh.iph)->ihl * sizeof(u32)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add IPv4 and IPv6 capable nf_conntrack port of the SIP conntrack/NAT helper.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

The NAT handling of the SIP helper has a few problems:

- Request headers are only mangled in the reply direction, From/To headers
  not at all, which can lead to authentication failures with DNAT in case
  the authentication domain is the IP address

- Contact headers in responses are only mangled for REGISTER responses

- Headers may be mangled even though they contain addresses not
  participating in the connection, like alternative addresses

- Packets are droppen when domain names are used where the helper expects
  IP addresses

This patch takes a different approach, instead of fixed rules what field
to mangle to what content, it adds symetric mapping of From/To/Via/Contact
headers, which allows to deal properly with echoed addresses in responses
and foreign addresses not belonging to the connection.
Signed-off-by: Patrick McHardy <kaber@trash.net>

SIP headers are generally case-insensitive, only SDP headers are
case sensitive.
Signed-off-by: Patrick McHardy <kaber@trash.net>

- Use enum for header field enumeration
- Use numerical value instead of pointer to header info structure to
  identify headers, unexport ct_sip_hdrs
- group SIP and SDP entries in header info structure
- remove double forward declaration of ct_sip_get_info
Signed-off-by: Patrick McHardy <kaber@trash.net>

The NAT helpr hooks are protected by RCU, but all of the
conntrack helpers test and use the global pointers instead
of copying them first using rcu_dereference()

Also replace synchronize_net() by synchronize_rcu() for clarity
since sychronizing only with packet receive processing is
insufficient to prevent races.
Signed-off-by: Patrick McHardy <kaber@trash.net>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add SIP connection tracking helper. Originally written by
Christian Hentschel <chentschel@arnet.com.ar>, some cleanup, minor
fixes and bidirectional SIP support added by myself.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>