tree 8d88690faf3d819e42719165cae62e9953555140
parent 77a78dec48386ce958196bf69f192ee76537c07d
author Patrick McHardy <kaber@trash.net> 1164764130 +0100
committer David S. Miller <davem@sunset.davemloft.net> 1165123886 -0800

[NETFILTER]: sip conntrack: better NAT handling

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>