<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/net/ipv4/netfilter, branch v5.5-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>netfilter: nf_flow_table_offload: add IPv6 support</title>
<updated>2019-11-15T22:44:47+00:00</updated>
<author>
<name>Pablo Neira Ayuso</name>
<email>pablo@netfilter.org</email>
</author>
<published>2019-11-13T13:08:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5c27d8d76ce810c6254cf5917a6019d824f34bd2'/>
<id>5c27d8d76ce810c6254cf5917a6019d824f34bd2</id>
<content type='text'>
Add nf_flow_rule_route_ipv6() and use it from the IPv6 and the inet
flowtable type definitions. Rename the nf_flow_rule_route() function to
nf_flow_rule_route_ipv4().

Adjust maximum number of actions, which now becomes 16 to leave
sufficient room for the IPv6 address mangling for NAT.

Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add nf_flow_rule_route_ipv6() and use it from the IPv6 and the inet
flowtable type definitions. Rename the nf_flow_rule_route() function to
nf_flow_rule_route_ipv4().

Adjust maximum number of actions, which now becomes 16 to leave
sufficient room for the IPv6 address mangling for NAT.

Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: nf_flow_table: hardware offload support</title>
<updated>2019-11-13T03:42:26+00:00</updated>
<author>
<name>Pablo Neira Ayuso</name>
<email>pablo@netfilter.org</email>
</author>
<published>2019-11-11T23:29:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c29f74e0df7a02b8303bcdce93a7c0132d62577a'/>
<id>c29f74e0df7a02b8303bcdce93a7c0132d62577a</id>
<content type='text'>
This patch adds the dataplane hardware offload to the flowtable
infrastructure. Three new flags represent the hardware state of this
flow:

* FLOW_OFFLOAD_HW: This flow entry resides in the hardware.
* FLOW_OFFLOAD_HW_DYING: This flow entry has been scheduled to be remove
  from hardware. This might be triggered by either packet path (via TCP
  RST/FIN packet) or via aging.
* FLOW_OFFLOAD_HW_DEAD: This flow entry has been already removed from
  the hardware, the software garbage collector can remove it from the
  software flowtable.

This patch supports for:

* IPv4 only.
* Aging via FLOW_CLS_STATS, no packet and byte counter synchronization
  at this stage.

This patch also adds the action callback that specifies how to convert
the flow entry into the flow_rule object that is passed to the driver.

Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds the dataplane hardware offload to the flowtable
infrastructure. Three new flags represent the hardware state of this
flow:

* FLOW_OFFLOAD_HW: This flow entry resides in the hardware.
* FLOW_OFFLOAD_HW_DYING: This flow entry has been scheduled to be remove
  from hardware. This might be triggered by either packet path (via TCP
  RST/FIN packet) or via aging.
* FLOW_OFFLOAD_HW_DEAD: This flow entry has been already removed from
  the hardware, the software garbage collector can remove it from the
  software flowtable.

This patch supports for:

* IPv4 only.
* Aging via FLOW_CLS_STATS, no packet and byte counter synchronization
  at this stage.

This patch also adds the action callback that specifies how to convert
the flow entry into the flow_rule object that is passed to the driver.

Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: nf_tables: add flowtable offload control plane</title>
<updated>2019-11-13T03:42:26+00:00</updated>
<author>
<name>Pablo Neira Ayuso</name>
<email>pablo@netfilter.org</email>
</author>
<published>2019-11-11T23:29:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8bb69f3b2918788435cbd5834c66682642c09fba'/>
<id>8bb69f3b2918788435cbd5834c66682642c09fba</id>
<content type='text'>
This patch adds the NFTA_FLOWTABLE_FLAGS attribute that allows users to
specify the NF_FLOWTABLE_HW_OFFLOAD flag. This patch also adds a new
setup interface for the flowtable type to perform the flowtable offload
block callback configuration.

Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds the NFTA_FLOWTABLE_FLAGS attribute that allows users to
specify the NF_FLOWTABLE_HW_OFFLOAD flag. This patch also adds a new
setup interface for the flowtable type to perform the flowtable offload
block callback configuration.

Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>icmp: remove duplicate code</title>
<updated>2019-11-05T22:03:11+00:00</updated>
<author>
<name>Matteo Croce</name>
<email>mcroce@redhat.com</email>
</author>
<published>2019-11-02T00:12:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=54074f1dbd6fbc0f0a085a54f3297ae26e424d59'/>
<id>54074f1dbd6fbc0f0a085a54f3297ae26e424d59</id>
<content type='text'>
The same code which recognizes ICMP error packets is duplicated several
times. Use the icmp_is_err() and icmpv6_is_err() helpers instead, which
do the same thing.

ip_multipath_l3_keys() and tcf_nat_act() didn't check for all the error types,
assume that they should instead.

Signed-off-by: Matteo Croce &lt;mcroce@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The same code which recognizes ICMP error packets is duplicated several
times. Use the icmp_is_err() and icmpv6_is_err() helpers instead, which
do the same thing.

ip_multipath_l3_keys() and tcf_nat_act() didn't check for all the error types,
assume that they should instead.

Signed-off-by: Matteo Croce &lt;mcroce@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: drop bridge nf reset from nf_reset</title>
<updated>2019-10-01T16:42:15+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2019-09-29T18:54:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=895b5c9f206eb7d25dc1360a8ccfc5958895eb89'/>
<id>895b5c9f206eb7d25dc1360a8ccfc5958895eb89</id>
<content type='text'>
commit 174e23810cd31
("sk_buff: drop all skb extensions on free and skb scrubbing") made napi
recycle always drop skb extensions.  The additional skb_ext_del() that is
performed via nf_reset on napi skb recycle is not needed anymore.

Most nf_reset() calls in the stack are there so queued skb won't block
'rmmod nf_conntrack' indefinitely.

This removes the skb_ext_del from nf_reset, and renames it to a more
fitting nf_reset_ct().

In a few selected places, add a call to skb_ext_reset to make sure that
no active extensions remain.

I am submitting this for "net", because we're still early in the release
cycle.  The patch applies to net-next too, but I think the rename causes
needless divergence between those trees.

Suggested-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 174e23810cd31
("sk_buff: drop all skb extensions on free and skb scrubbing") made napi
recycle always drop skb extensions.  The additional skb_ext_del() that is
performed via nf_reset on napi skb recycle is not needed anymore.

Most nf_reset() calls in the stack are there so queued skb won't block
'rmmod nf_conntrack' indefinitely.

This removes the skb_ext_del from nf_reset, and renames it to a more
fitting nf_reset_ct().

In a few selected places, add a call to skb_ext_reset to make sure that
no active extensions remain.

I am submitting this for "net", because we're still early in the release
cycle.  The patch applies to net-next too, but I think the rename causes
needless divergence between those trees.

Suggested-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: fix coding-style errors.</title>
<updated>2019-09-13T09:39:38+00:00</updated>
<author>
<name>Jeremy Sowden</name>
<email>jeremy@azazel.net</email>
</author>
<published>2019-09-13T08:13:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b0edba2af7154c82c28a4828f483c102ab201326'/>
<id>b0edba2af7154c82c28a4828f483c102ab201326</id>
<content type='text'>
Several header-files, Kconfig files and Makefiles have trailing
white-space.  Remove it.

In netfilter/Kconfig, indent the type of CONFIG_NETFILTER_NETLINK_ACCT
correctly.

There are semicolons at the end of two function definitions in
include/net/netfilter/nf_conntrack_acct.h and
include/net/netfilter/nf_conntrack_ecache.h. Remove them.

Fix indentation in nf_conntrack_l4proto.h.

Signed-off-by: Jeremy Sowden &lt;jeremy@azazel.net&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Several header-files, Kconfig files and Makefiles have trailing
white-space.  Remove it.

In netfilter/Kconfig, indent the type of CONFIG_NETFILTER_NETLINK_ACCT
correctly.

There are semicolons at the end of two function definitions in
include/net/netfilter/nf_conntrack_acct.h and
include/net/netfilter/nf_conntrack_ecache.h. Remove them.

Fix indentation in nf_conntrack_l4proto.h.

Signed-off-by: Jeremy Sowden &lt;jeremy@azazel.net&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: synproxy: rename mss synproxy_options field</title>
<updated>2019-08-03T16:39:08+00:00</updated>
<author>
<name>Fernando Fernandez Mancera</name>
<email>ffmancera@riseup.net</email>
</author>
<published>2019-07-10T10:05:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8c0bb7873815bf8c3c4dfb24e8ebf4fefb4c35d2'/>
<id>8c0bb7873815bf8c3c4dfb24e8ebf4fefb4c35d2</id>
<content type='text'>
After introduce "mss_encode" field in the synproxy_options struct the field
"mss" is a little confusing. It has been renamed to "mss_option".

Signed-off-by: Fernando Fernandez Mancera &lt;ffmancera@riseup.net&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
After introduce "mss_encode" field in the synproxy_options struct the field
"mss" is a little confusing. It has been renamed to "mss_option".

Signed-off-by: Fernando Fernandez Mancera &lt;ffmancera@riseup.net&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: synproxy: fix erroneous tcp mss option</title>
<updated>2019-07-16T11:17:01+00:00</updated>
<author>
<name>Fernando Fernandez Mancera</name>
<email>ffmancera@riseup.net</email>
</author>
<published>2019-07-10T10:05:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b83329fb473f29d34d85d642e3a3313bb2871fa9'/>
<id>b83329fb473f29d34d85d642e3a3313bb2871fa9</id>
<content type='text'>
Now synproxy sends the mss value set by the user on client syn-ack packet
instead of the mss value that client announced.

Fixes: 48b1de4c110a ("netfilter: add SYNPROXY core/target")
Signed-off-by: Fernando Fernandez Mancera &lt;ffmancera@riseup.net&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now synproxy sends the mss value set by the user on client syn-ack packet
instead of the mss value that client announced.

Fixes: 48b1de4c110a ("netfilter: add SYNPROXY core/target")
Signed-off-by: Fernando Fernandez Mancera &lt;ffmancera@riseup.net&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: Update obsolete comments referring to ip_conntrack</title>
<updated>2019-07-16T11:17:00+00:00</updated>
<author>
<name>Yonatan Goldschmidt</name>
<email>yon.goldschmidt@gmail.com</email>
</author>
<published>2019-07-08T22:57:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=05ba4c895363db795f3d54f2da0de56d6520e52d'/>
<id>05ba4c895363db795f3d54f2da0de56d6520e52d</id>
<content type='text'>
In 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") the new
generic nf_conntrack was introduced, and it came to supersede the old
ip_conntrack.

This change updates (some) of the obsolete comments referring to old
file/function names of the ip_conntrack mechanism, as well as removes a
few self-referencing comments that we shouldn't maintain anymore.

I did not update any comments referring to historical actions (e.g,
comments like "this file was derived from ..." were left untouched, even
if the referenced file is no longer here).

Signed-off-by: Yonatan Goldschmidt &lt;yon.goldschmidt@gmail.com&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") the new
generic nf_conntrack was introduced, and it came to supersede the old
ip_conntrack.

This change updates (some) of the obsolete comments referring to old
file/function names of the ip_conntrack mechanism, as well as removes a
few self-referencing comments that we shouldn't maintain anymore.

I did not update any comments referring to historical actions (e.g,
comments like "this file was derived from ..." were left untouched, even
if the referenced file is no longer here).

Signed-off-by: Yonatan Goldschmidt &lt;yon.goldschmidt@gmail.com&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: nf_conntrack_sip: fix expectation clash</title>
<updated>2019-07-16T11:16:59+00:00</updated>
<author>
<name>xiao ruizhu</name>
<email>katrina.xiaorz@gmail.com</email>
</author>
<published>2019-07-04T03:31:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3c00fb0bf0e0f061715c04ad609de93ddc046aa1'/>
<id>3c00fb0bf0e0f061715c04ad609de93ddc046aa1</id>
<content type='text'>
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 |&lt;----------------------|5060
           |      100 Trying       |
      5060 |----------------------&gt;|5060
           |      183 SDP          |
      5060 |----------------------&gt;|5060    ===&gt; Conntrack 1
           |       PRACK           |
     50601 |&lt;----------------------|5060
           |    200 OK (PRACK)     |
     50601 |----------------------&gt;|5060
           |    200 OK (INVITE)    |
      5060 |----------------------&gt;|5060
           |        ACK            |
     50601 |&lt;----------------------|5060
           |                       |
           |&lt;--- RTP stream ------&gt;|
           |                       |
           |    INVITE SDP (t38)   |
     50601 |----------------------&gt;|5060    ===&gt; 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&amp;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 |&lt;------------------| 5060  ==&gt; CT1
       |       200         |
  5060 |------------------&gt;| 5060
       |                   |
       |   INVITE SDP(1)   |
  5060 |&lt;------------------| 5060
       | 300(multi choice) |
  5060 |------------------&gt;| 5060                    SERVER B
       |       ACK         |
  5060 |&lt;------------------| 5060
                                  |    INVITE SDP(2)    |
                             5060 |--------------------&gt;| 5060  ==&gt; CT2
                                  |       100           |
                             5060 |&lt;--------------------| 5060
                                  | 200(contact changes)|
                             5060 |&lt;--------------------| 5060
                                  |       ACK           |
                             5060 |--------------------&gt;| 50601 ==&gt; CT3
                                  |                     |
                                  |&lt;--- RTP stream ----&gt;|
                                  |                     |
                                  |       BYE           |
                             5060 |&lt;--------------------| 50601
                                  |       200           |
                             5060 |--------------------&gt;| 50601
       |   INVITE SDP(3)   |
  5060 |&lt;------------------| 5060  ==&gt; CT1

CPE sends an INVITE request(1) to Server A, and creates a RTP&amp;RTCP expect
pair for this Conntrack 1 (CT1). Server A responds 300 to redirect to
Server B. The RTP&amp;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&amp;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 &lt;katrina.xiaorz@gmail.com&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 |&lt;----------------------|5060
           |      100 Trying       |
      5060 |----------------------&gt;|5060
           |      183 SDP          |
      5060 |----------------------&gt;|5060    ===&gt; Conntrack 1
           |       PRACK           |
     50601 |&lt;----------------------|5060
           |    200 OK (PRACK)     |
     50601 |----------------------&gt;|5060
           |    200 OK (INVITE)    |
      5060 |----------------------&gt;|5060
           |        ACK            |
     50601 |&lt;----------------------|5060
           |                       |
           |&lt;--- RTP stream ------&gt;|
           |                       |
           |    INVITE SDP (t38)   |
     50601 |----------------------&gt;|5060    ===&gt; 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&amp;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 |&lt;------------------| 5060  ==&gt; CT1
       |       200         |
  5060 |------------------&gt;| 5060
       |                   |
       |   INVITE SDP(1)   |
  5060 |&lt;------------------| 5060
       | 300(multi choice) |
  5060 |------------------&gt;| 5060                    SERVER B
       |       ACK         |
  5060 |&lt;------------------| 5060
                                  |    INVITE SDP(2)    |
                             5060 |--------------------&gt;| 5060  ==&gt; CT2
                                  |       100           |
                             5060 |&lt;--------------------| 5060
                                  | 200(contact changes)|
                             5060 |&lt;--------------------| 5060
                                  |       ACK           |
                             5060 |--------------------&gt;| 50601 ==&gt; CT3
                                  |                     |
                                  |&lt;--- RTP stream ----&gt;|
                                  |                     |
                                  |       BYE           |
                             5060 |&lt;--------------------| 50601
                                  |       200           |
                             5060 |--------------------&gt;| 50601
       |   INVITE SDP(3)   |
  5060 |&lt;------------------| 5060  ==&gt; CT1

CPE sends an INVITE request(1) to Server A, and creates a RTP&amp;RTCP expect
pair for this Conntrack 1 (CT1). Server A responds 300 to redirect to
Server B. The RTP&amp;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&amp;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 &lt;katrina.xiaorz@gmail.com&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
