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>
- 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>
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>
