12 Jan
2021
12 Jan
'21
6:51 p.m.
It is my understanding that for outbound connections, subsequent transactions to the same
destination IP:port reuse an existing TLS socket (if one exists) by design. By the logs,
it appears that this matching takes place early in the processing so there is no regard
for a new outbound transaction that has different SNI. Is this correct? Is there a way to
force a new outbound TLS connection for a new transaction based on some other identifier?
- Charles Phillips
On Jan 11, 2021, at 9:00 AM, Charles Phillips
<charles(a)rustybike.com> wrote:
That is what I figured was happening. I have tried sending it back to a standard routing
block, but perhaps I am doing it incorrectly.
When I try to send it back to a regular routing block I get the following error:
CRITICAL: tm [tm.c:1754]: _w_t_relay_to(): unsupported route type: 64
Config:
event_route[tm:local-request] {
sip_trace();
if(is_method("OPTIONS") && $ru =~ "pstnhub.microsoft.com
<http://pstnhub.microsoft.com/>") {
$var(domain) = $fd;
append_hf("Contact: <sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>>\r\n");
xlog("L_INFO", “TEAMS Contact: $var(domain)\r\n");
route(TEAMS_SEND);
}
xlog("L_INFO", "Sent out tm request: $mb\n");
}
route[TEAMS_SEND] {
$var(domain) = $fd;
$xavp(tls=>server_name) = $var(domain);
$xavp(tls[0]=>server_id) = $var(domain);
$du = "sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>";
t_relay();
}
For testing, I also tried generating the packets in a normal route using t_uac_send and
controlling it with rtimer. As ugly a hack that this approach is, it did manage to create
the packets and set the xavp as required (although, it certainly wouldn’t help dispatcher
know if a gateway is offline…). Additional trouble is that if a second domain attempts to
send OPTIONS packets in the while loop (see below) it goes out the same TLS connection, so
it is rejected.
Config:
route["PING-TEAMS"] {
sql_query("db", "select domain from domain;",
"domain_list");
$var(i) = 0;
while ($dbr(domain_list=>[$var(i),0]) != $null) {
$var(domain) = $dbr(domain_list=>[$var(i),0]);
xlog(“OPTIONS from domain name $var(domain)");
$xavp(tls=>server_name) = $var(domain);
$xavp(tls[0]=>server_id) = $var(domain);
$du = "sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>";
t_uac_send ("OPTIONS", "sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>",
"sip:sip3.pstnhub.microsoft.com;transport=tls
<sip:sip3.pstnhub.microsoft.com;transport=tls>", "", "From:
sip:$var(domain) <sip:$var(domain)>\r\nTo:
sip:sip3.pstnhub.microsoft.com;transport=tls
<sip:sip3.pstnhub.microsoft.com;transport=tls>\r\nContact:
<sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>>\r\n", "");
sleep(2);
t_uac_send ("OPTIONS", "sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>",
"sip:sip2.pstnhub.microsoft.com;transport=tls
<sip:sip2.pstnhub.microsoft.com;transport=tls>", "", "From:
sip:$var(domain) <sip:$var(domain)>\r\nTo:
sip:sip2.pstnhub.microsoft.com;transport=tls
<sip:sip2.pstnhub.microsoft.com;transport=tls>\r\nContact:
<sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>>\r\n", "");
sleep(2);
t_uac_send ("OPTIONS", "sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>",
"sip:sip.pstnhub.microsoft.com;transport=tls
<sip:sip.pstnhub.microsoft.com;transport=tls>", "", "From:
sip:$var(domain) <sip:$var(domain)>\r\nTo:
sip:sip.pstnhub.microsoft.com;transport=tls
<sip:sip.pstnhub.microsoft.com;transport=tls>\r\nContact:
<sip:$var(domain):5061;transport=tls
<sip:$var(domain):5061;transport=tls>>\r\n", "");
sleep(5);
$var(i) = $var(i) + 1;
}
}
200 from MS on domain 0:
2021/01/11 08:48:31.291048 52.114.7.24:5061 -> *myip*:52606
SIP/2.0 200 OK
FROM: <sip:100.sbc.*mydomain*.net
<sip:100.sbc.*mydomain*.net>>;tag=3393f0703fb0ccaca74109ff37de39f5-5a503a0a
TO: <sip:sip3.pstnhub.microsoft.com <sip:sip3.pstnhub.microsoft.com>>
CSEQ: 10 OPTIONS
CALL-ID: 0f37a09f409a4e41-24410(a)127.0.0.1
<mailto:0f37a09f409a4e41-24410@127.0.0.1>
VIA: SIP/2.0/TLS *myip*:5061;branch=z9hG4bK9306.42d92227000000000000000000000000.0
CONTENT-LENGTH: 0
ALLOW: INVITE,ACK,OPTIONS,CANCEL,BYE,NOTIFY
SERVER: Microsoft.PSTNHub.SIPProxy v.2020.12.28.1 i.ASEA.0
403 from MS on domain 1:
2021/01/11 08:49:39.755005 52.114.7.24:5061 -> *myip*:52606
SIP/2.0 403 Forbidden
FROM: <sip:101.sbc.*mydomain*.net
<sip:101.sbc.*mydomain*.net>>;tag=3393f0703fb0ccaca74109ff37de39f5-69555a28
TO: <sip:sip3.pstnhub.microsoft.com <sip:sip3.pstnhub.microsoft.com>>
CSEQ: 10 OPTIONS
CALL-ID: 0f37a09f409a4e44-24410(a)127.0.0.1
<mailto:0f37a09f409a4e44-24410@127.0.0.1>
VIA: SIP/2.0/TLS *myip*:5061;branch=z9hG4bK4306.973e1562000000000000000000000000.0
REASON: Q.850;cause=63;text="00cce062-66c6-45a4-8b5c-ccd48b71a9f6;Provided Trunk
FQDN '101.sbc.*mydomain*.net' is not allowed. Connection allows
ollowing fqdns: 100.sbc.*mydomain*.net, 100.sbc.*mydomain*.net."
CONTENT-LENGTH: 0
ALLOW: INVITE,ACK,OPTIONS,CANCEL,BYE,NOTIFY
SERVER: Microsoft.PSTNHub.SIPProxy v.2020.12.28.1 i.ASEA.0
- Charles Phillips
> On Jan 11, 2021, at 4:13 AM, Daniel-Constantin Mierla <miconda(a)gmail.com
<mailto:miconda@gmail.com>> wrote:
>
> Hello,
>
> the xavp_cfg set in the event_route is not propagated (kept) to the moment when the
message is sent out to tls. The event_route[tm:local-request] is executed when the local
request is constructed, terminated before sending out, so whatever avp/xavp is set in the
event route are deleted when the block execution is terminated.
>
> It requires another solution here, I am thinking about what can be done and will be
added soon in the master branch.
>
> Meanwhile, a workaround is to look traffic back to kamailio so the routing happens
over request_route block, where you can set the xavp.
>
> Cheers,
> Daniel
>
> On 08.01.21 22:23, Charles Phillips wrote:
>> Thanks Daniel, I needed some certainty to get unstuck. It appears that the
problem is actually related to the TLS config. I am using multiple TLS configs, so it
looks like the problem may be that the server_name server_id are not being set, so the
reply is returning to the default TLS config. Not to mention that when I set the testing
domains certs under the default config, it works...
>>
>> This is observed in the logs:
>>
>> tls_get_connect_server_name(): xavp with outbound server name not found
>> tls_get_connect_server_id(): xavp with outbound server id not found
>> tls_complete_init(): Using initial TLS domain TLSc<default>
>>
>> Is there a way to set this with xavp_cfg in the event_route? I have read that
section and tried may combinations, but since the OPTIONs packets from the dispatcher
module do not seem to traverse the standard routes, I am not sure how to handle this.
>>
>> Any advice would be greatly appreciated!
>>
>>
>> - Charles Phillips
>>
>>
>>
>>
>>> On Jan 8, 2021, at 12:56 PM, Daniel-Constantin Mierla <miconda(a)gmail.com
<mailto:miconda@gmail.com>> wrote:
>>>
>>> Hello,
>>>
>>> there is an option that you can set to reuse the port for tcp/tls
connections, but even so it is a best effort and it is not going to ensured -- all these
are practically flags set to the sockets and the kernel (tcp stack) decides after all.
>>>
>>> Anyhow, the rport is mainly useful for connectionless communication, like
UDP. For tcp/tls, the SIP specs demand to reuse the existing connections. As I did several
Kamailio-MSTeams interconnectivity deployments, I can tell that the source port was never
a problem. The TLS connection is kept open and MSTeams sends back traffic on it.
>>>
>>> Cheers,
>>> Daniel
>>>
>>> On 08.01.21 14:32, Charles Phillips wrote:
>>>> Thanks for the quick response Joel. Yes, I have read the article and I
have tested and confirmed that I am correctly appending the contact header (I probably
should have left that in the snippet for clarity). Below is an example of Kamailio
setting up the connection. It is going out port 46245 this time, but it is random.
>>>>
>>>> 07:59:23.572319 IP *my.kamailio.server*.46245 >
*ms.teams.server*.sip-tls: Flags [P.], seq 1:518, ack 1, win 502, length 517
>>>> 07:59:23.802458 IP *ms.teams.server*.sip-tls >
*my.kamailio.server*.46245: Flags [P.], seq 1:3767, ack 518, win 2051, length 3766
>>>>
>>>> The TLS connection shows as successful in the logs.
>>>>
>>>>
>>>> - Charles
>>>>
>>>>
>>>> Date: Thu, 7 Jan 2021 19:12:10 -0800
>>>> From: Joel Serrano <joel(a)textplus.com
<mailto:joel@textplus.com>>
>>>> To: "Kamailio (SER) - Users Mailing List"
>>>> <sr-users(a)lists.kamailio.org
<mailto:sr-users@lists.kamailio.org>>
>>>> Subject: Re: [SR-Users] Source Port on TLS OPTIONS from Dispatcher
>>>> Message-ID:
>>>> <CAMtXxQnLtEyD=40cwKembxiyj3D778eK=+5JD7sL4CvYbYXF1g(a)mail.gmail.com
<mailto:CAMtXxQnLtEyD=40cwKembxiyj3D778eK=+5JD7sL4CvYbYXF1g@mail.gmail.com>>
>>>> Content-Type: text/plain; charset="utf-8"
>>>>
>>>> Hi Charles,
>>>>
>>>> I don't think your issue is rport, make sure you are setting the
Contact
>>>> header correctly.
>>>>
>>>> Have you checked this blog post:
>>>> https://skalatan.de/en/blog/kamailio-sbc-teams
<https://skalatan.de/en/blog/kamailio-sbc-teams> ?
>>>>
>>>> There is a specific section that talks about how to tell Kamailio to
send
>>>> the OPTIONS like MS Teams wants them.
>>>>
>>>> Good luck,
>>>> Joel.
>>>>
>>>>
>>>>> On Jan 7, 2021, at 7:31 PM, Charles Phillips
<charles(a)rustybike.com <mailto:charles@rustybike.com>> wrote:
>>>>>
>>>>> Hello all. As they say in radio, “long time listener, first time
caller”
>>>>>
>>>>> Anyway, I am having trouble getting past the following road block and
any help would be greatly appreciated.
>>>>>
>>>>> Kamailio version is 5.4.3
>>>>>
>>>>> When attempting to use dispatcher to send OPTIONS packets to several
TLS destinations, the packets are leaving the Kamailio server on random ports. This is a
problem because the servers I am sending the OPTIONS to (MS Teams) are enforcing rport so
the responses are returned to a port that Kamailio is not listening on. I have tried to
force the socket in the event route (relevant parts of snippet below) but it does not
appear to help. I should also mention that I am not behind NAT and the TLS socket is
specified in the dispatcher attrs.
>>>>>
>>>>> event_route[tm:local-request] {
>>>>> sip_trace();
>>>>>
>>>>>
>>>>> $fs = “tls:**ip-address**:5061”;
>>>>>
>>>>>
>>>>> }
>>>>>
>>>>> I have used Kamailio as a TLS server for many projects, but this is
my first time as a client. I am sure I am missing something.
>>>>>
>>>>> - Charles
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Kamailio (SER) - Users Mailing List
>>>> sr-users(a)lists.kamailio.org <mailto:sr-users@lists.kamailio.org>
>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
<https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users>
>>> --
>>> Daniel-Constantin Mierla -- www.asipto.com <http://www.asipto.com/>
>>> www.twitter.com/miconda <http://www.twitter.com/miconda> --
www.linkedin.com/in/miconda <http://www.linkedin.com/in/miconda>
>>> Funding: https://www.paypal.me/dcmierla
<https://www.paypal.me/dcmierla>
> --
> Daniel-Constantin Mierla -- www.asipto.com <http://www.asipto.com/>
> www.twitter.com/miconda <http://www.twitter.com/miconda> --
www.linkedin.com/in/miconda <http://www.linkedin.com/in/miconda>
> Funding: https://www.paypal.me/dcmierla <https://www.paypal.me/dcmierla>