netfilter: nf_conntrack_sip: fix expectation clash

When conntracks change during a dialog, SDP messages may be sent from
different conntracks to establish expects with identical tuples. In this
case expects conflict may be detected for the 2nd SDP message and end up
with a process failure.

The fixing here is to reuse an existing expect who has the same tuple for a
different conntrack if any.

Here are two scenarios for the case.

1)
SERVER CPE

| INVITE SDP |
5060 |<----------------------|5060
| 100 Trying |
5060 |---------------------->|5060
| 183 SDP |
5060 |---------------------->|5060 ===> Conntrack 1
| PRACK |
50601 |<----------------------|5060
| 200 OK (PRACK) |
50601 |---------------------->|5060
| 200 OK (INVITE) |
5060 |---------------------->|5060
| ACK |
50601 |<----------------------|5060
| |
|<--- RTP stream ------>|
| |
| INVITE SDP (t38) |
50601 |---------------------->|5060 ===> Conntrack 2

With a certain configuration in the CPE, SIP messages "183 with SDP" and
"re-INVITE with SDP t38" will go through the sip helper to create
expects for RTP and RTCP.

It is okay to create RTP and RTCP expects for "183", whose master
connection source port is 5060, and destination port is 5060.

In the "183" message, port in Contact header changes to 50601 (from the
original 5060). So the following requests e.g. PRACK and ACK are sent to
port 50601. It is a different conntrack (let call Conntrack 2) from the
original INVITE (let call Conntrack 1) due to the port difference.

In this example, after the call is established, there is RTP stream but no
RTCP stream for Conntrack 1, so the RTP expect created upon "183" is
cleared, and RTCP expect created for Conntrack 1 retains.

When "re-INVITE with SDP t38" arrives to create RTP&RTCP expects, current
ALG implementation will call nf_ct_expect_related() for RTP and RTCP. The
expects tuples are identical to those for Conntrack 1. RTP expect for
Conntrack 2 succeeds in creation as the one for Conntrack 1 has been
removed. RTCP expect for Conntrack 2 fails in creation because it has
idential tuples and 'conflict' with the one retained for Conntrack 1. And
then result in a failure in processing of the re-INVITE.

2)

SERVER A CPE

| REGISTER |
5060 |<------------------| 5060 ==> CT1
| 200 |
5060 |------------------>| 5060
| |
| INVITE SDP(1) |
5060 |<------------------| 5060
| 300(multi choice) |
5060 |------------------>| 5060 SERVER B
| ACK |
5060 |<------------------| 5060
| INVITE SDP(2) |
5060 |-------------------->| 5060 ==> CT2
| 100 |
5060 |<--------------------| 5060
| 200(contact changes)|
5060 |<--------------------| 5060
| ACK |
5060 |-------------------->| 50601 ==> CT3
| |
|<--- RTP stream ---->|
| |
| BYE |
5060 |<--------------------| 50601
| 200 |
5060 |-------------------->| 50601
| INVITE SDP(3) |
5060 |<------------------| 5060 ==> CT1

CPE sends an INVITE request(1) to Server A, and creates a RTP&RTCP expect
pair for this Conntrack 1 (CT1). Server A responds 300 to redirect to
Server B. The RTP&RTCP expect pairs created on CT1 are removed upon 300
response.

CPE sends the INVITE request(2) to Server B, and creates an expect pair
for the new conntrack (due to destination address difference), let call
CT2. Server B changes the port to 50601 in 200 OK response, and the
following requests ACK and BYE from CPE are sent to 50601. The call is
established. There is RTP stream and no RTCP stream. So RTP expect is
removed and RTCP expect for CT2 retains.

As BYE request is sent from port 50601, it is another conntrack, let call
CT3, different from CT2 due to the port difference. So the BYE request will
not remove the RTCP expect for CT2.

Then another outgoing call is made, with the same RTP port being used (not
definitely but possibly). CPE firstly sends the INVITE request(3) to Server
A, and tries to create a RTP&RTCP expect pairs for this CT1. In current ALG
implementation, the RTCP expect for CT1 fails in creation because it
'conflicts' with the residual one for CT2. As a result the INVITE request
fails to send.

Signed-off-by: xiao ruizhu <katrina.xiaorz@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 93

Based on 1 normalized pattern(s):

this code is free software you can redistribute it and or modify it
under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not see http www gnu org licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520075212.233647300@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ipvs: add full ipv6 support to nfct

Prepare NFCT to support IPv6 for FTP:

- Do not restrict the expectation callback to PF_INET

- Split the debug messages, so that the 160-byte limitation
in IP_VS_DBG_BUF is not exceeded when printing many IPv6
addresses. This means no more than 3 addresses in one message,
i.e. 1 tuple with 2 addresses or 1 connection with 3 addresses.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: remove nf_ct_is_untracked

This function is now obsolete and always returns false.
This change has no effect on generated code.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

ipvs: use nf_ct_kill helper

Once timer is removed from nf_conn struct we cannot open-code
the removal sequence anymore.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

ipvs: don't alter conntrack in OPS mode

When using OPS mode in conjunction with SIP persistent-engine, packets
originating from the same ip-address/port could be balanced to different
real servers, and (to properly handle SIP responses) OPS connections
are created in the in-out direction too, where ip_vs_update_conntrack()
is called to modify the reply tuple.

As a result, there can be collision of conntrack tuples, causing random
packet drops, as explained below:

conntrack1: orig=CIP->VIP, reply=RIP1->CIP
conntrack2: orig=RIP2->CIP, reply=CIP->VIP

Tuple CIP->VIP is both in orig of conntrack1 and reply of conntrack2.
The collision triggers packet drop inside nf_conntrack processing.

In addition, the current implementation deletes the conntrack object at
every expire of an OPS connection (once every forwarded packet), to have
it recreated from scratch at next packet traversing IPVS.

Since in OPS mode, by definition, we don't expect any associated
response, the choices implemented in this patch are:
a) don't call nf_conntrack_alter_reply() for OPS connections inside
ip_vs_update_conntrack().
b) don't delete the conntrack object at OPS connection expire.

The result is that created conntrack objects for each tuple CIP->VIP,
RIP-N->CIP, etc. are left in UNREPLIED state and not modified by IPVS
OPS connection management. This eliminates packet drops and leaves
a single conntrack object for each tuple packets are sent from.

Signed-off-by: Marco Angaroni <marcoangaroni@gmail.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

ipvs: Pass ipvs not net to ip_vs_fill_conn

ipvs is what is actually desired so change the parameter and the modify
the callers to pass struct netns_ipvs.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

ipvs: Store ipvs not net in struct ip_vs_conn

In practice struct netns_ipvs is as meaningful as struct net and more
useful as it holds the ipvs specific data. So store a pointer to
struct netns_ipvs.

Update the accesses of conn->net to access conn->ipvs->net instead.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

netfilter: nf_conntrack: push zone object into functions

This patch replaces the zone id which is pushed down into functions
with the actual zone object. It's a bigger one-time change, but
needed for later on extending zones with a direction parameter, and
thus decoupling this additional information from all call-sites.

No functional changes in this patch.

The default zone becomes a global const object, namely nf_ct_zone_dflt
and will be returned directly in various cases, one being, when there's
f.e. no zoning support.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

ipvs: correct usage/allocation of seqadj ext in ipvs

The IPVS FTP helper ip_vs_ftp could trigger an OOPS in nf_ct_seqadj_set,
after commit 41d73ec053d2 (netfilter: nf_conntrack: make sequence number
adjustments usuable without NAT).

This is because, the seqadj ext is now allocated dynamically, and the
IPVS code didn't handle this situation. Fix this in the IPVS nfct
code by invoking the alloc function nfct_seqadj_ext_add().

Fixes: 41d73ec053d2 (netfilter: nf_conntrack: make sequence number adjustments usuable without NAT)
Suggested-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

netfilter: Fix FSF address in file headers

Several files refer to an old address for the Free Software Foundation
in the file header comment. Resolve by replacing the address with
the URL <http://www.gnu.org/licenses/> so that we do not have to keep
updating the header comments anytime the address changes.

CC: netfilter@vger.kernel.org
CC: Pablo Neira Ayuso <pablo@netfilter.org>
CC: Patrick McHardy <kaber@trash.net>
CC: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvs: remove silly double assignment

I don't even want to think what the C spec says for this 8)

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

ipvs: Remove unused parameter from ip_vs_confirm_conntrack()

Acked-by: Julian Anastasov <ja@ssi.bg>
Acked-by Hans Schillstrom <hans@schillstrom.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

IPVS: netns, connection hash got net as param.

Connection hash table is now name space aware.
i.e. net ptr >> 8 is xor:ed to the hash,
and this is the first param to be compared.
The net struct is 0xa40 in size ( a little bit smaller for 32 bit arch:s)
and cache-line aligned, so a ptr >> 5 might be a more clever solution ?

All lookups where net is compared uses net_eq() which returns 1 when netns
is disabled, and the compiler seems to do something clever in that case.

ip_vs_conn_fill_param() have *net as first param now.

Three new inlines added to keep conn struct smaller
when names space is disabled.
- ip_vs_conn_net()
- ip_vs_conn_net_set()
- ip_vs_conn_net_eq()

*v3
moved net compare to the end in "fast path"

Signed-off-by: Hans Schillstrom <hans.schillstrom@ericsson.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

IPVS: Add struct ip_vs_conn_param

Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Julian Anastasov <ja@ssi.bg>

ipvs: netfilter connection tracking changes

Add more code to IPVS to work with Netfilter connection
tracking and fix some problems.

- Allow IPVS to be compiled without connection tracking as in
2.6.35 and before. This can avoid keeping conntracks for all
IPVS connections because this costs memory. ip_vs_ftp still
depends on connection tracking and NAT as implemented for 2.6.36.

- Add sysctl var "conntrack" to enable connection tracking for
all IPVS connections. For loaded IPVS directors it needs
tuning of nf_conntrack_max limit.

- Add IP_VS_CONN_F_NFCT connection flag to request the connection
to use connection tracking. This allows user space to provide this
flag, for example, in dest->conn_flags. This can be useful to
request connection tracking per real server instead of forcing it
for all connections with the "conntrack" sysctl. This flag is
set currently only by ip_vs_ftp and of course by "conntrack" sysctl.

- Add ip_vs_nfct.c file to hold all connection tracking code,
by this way main code should not depend of netfilter conntrack
support.

- Return back the ip_vs_post_routing handler as in 2.6.35 and use
skb->ipvs_property=1 to allow IPVS to work without connection
tracking

Connection tracking:

- most of the code is already in 2.6.36-rc

- alter conntrack reply tuple for LVS-NAT connections when first packet
from client is forwarded and conntrack state is NEW or RELATED.
Additionally, alter reply for RELATED connections from real server,
again for packet in original direction.

- add IP_VS_XMIT_TUNNEL to confirm conntrack (without altering
reply) for LVS-TUN early because we want to call nf_reset. It is
needed because we add IPIP header and the original conntrack
should be preserved, not destroyed. The transmitted IPIP packets
can reuse same conntrack, so we do not set skb->ipvs_property.

- try to destroy conntrack when the IPVS connection is destroyed.
It is not fatal if conntrack disappears before that, it depends
on the used timers.

Fix problems from long time:

- add skb->ip_summed = CHECKSUM_NONE for the LVS-TUN transmitters

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Patrick McHardy <kaber@trash.net>