8 Jun
2016
8 Jun
'16
10:49 p.m.
Hello,
the problem is that the ACK doesn't have in R-URI the address from
Contact header in 200ok, as required by RFC.
The R-URI and the Route are both having the IP of Kamailio, so there is
no other address where to send the ACK.
ACK sip:10.15.1.30:5060 SIP/2.0
*Route: sip:10.15.1.30;lr;ftag=SDkbo9901-42090
You have to track why the ACK is not coming with R-URI having the
address from Contact of 200ok. See how 200ok is received by caller and
how caller's devices sets the R-URI. Might be the sbc or other hop
breaking it.
If you can't fix the device/application messing up the R-URI for the
ACK, then you can try some solutions in kamailio:
1) use set_contact_alias() for 18x/200ok responses and then
handle_ruri_alias() for ACK and other requests within dialog.
if(has_totag() && uri==myself && $ru=~";alias=") {
handle_ruri_alias();
if($du != $null) {
$ru = $du;
}
}
# continue with loose_route(), etc ...
It works if the devices messes up only the host/port of the R-URI in
ACK, but keeps the other parameters.
2) if 1 doesn't work, use htable to store association between
callid+from-tag and the contact address of 200ok, then use it for
requests within dialog that have uri==myself
reply_route {
...
if(is_method("INVITE") && status=="200") {
$sht(ct=>$ci::$ft) = $sel(contact.uri);
}
...
}
request_route {
...
if(has_totag() && uri==myself) {
if($sht(ct=>$ci::$ft) != $null) {
$ru = $sht(ct=>$ci::$ft);
}
}
# continue with loose_route(), etc ...
...
}
You have to set the auto-expire for htable ct to the maximum lifetime
for a dialog. You can delete the items from ct hash table (or reduce
their expire value) when processing the BYE or the response to BYE. Note
that for bye you have to try the combination $ci:$ft as well as $ci:$tt
3) if you have only one asterisk, then if the request has to-tag and a
route header and uri==myself, then just set $ru to sip:ip:port of asterisk
Cheers,
Daniel
On 08/06/16 12:18, Francisco Valentin Vinagrero wrote:
Hi there,
I’m having an issue in a SBC (ACME) -> KAMAILIO -> Asterisk scenario
with an ACK that gets ignored in Kamailio because it does not match
any transaction.
The INVITE coming from the SBC looks like this (only relevant headers
and hidden numbers for simplicity – SBC has IP .12 , Kamailio .30 and
Asterisk .34)
INVITE sip:mynumber@10.15.1.30:5060
SIP/2.0
Via: SIP/2.0/UDP
10.15.1.12:5060;branch=z9hG4bKdd1m7b00aom47rggc700.1
To: <sip:
mynumber@10.15.1.30:5060>
From:
<sip:a-number@10.15.1.12;user=phone>;tag=SDkbo9901-42090
P-Asserted-Identity: <sip: a-number
@10.15.1.12>
Call-ID:
SDkbo9901-71a1d17456b829b4c422af61de9eee7e-ao32g50
CSeq: 1
INVITE
Contact:
<sip:41754112601@10.15.1.12:5060;transport=udp>
And its forwarded to Asterisk with the Record-Route header:
INVITE sip: mynumber @10.15.1.30:5060 SIP/2.0
*Record-Route: <sip:10.15.1.30;lr=on;ftag=SDkbo9901-42090>
*Via: SIP/2.0/UDP
10.15.1.30;branch=z9hG4bK1c02.7dc1b94be22d8780df5141f9ba3c5b7b.0
Via: SIP/2.0/UDP
10.15.1.12:5060;branch=z9hG4bKdd1m7b00aom47rggc700.1
To: <sip:mynumber@10.15.1.30:5060>
From: <sip:a-number@10.15.1.12;user=phone>;tag=SDkbo9901-42090
P-Asserted-Identity: <sip:a-number@10.15.1.12>
Call-ID: SDkbo9901-71a1d17456b829b4c422af61de9eee7e-ao32g50
CSeq: 1 INVITE
Contact: <sip:a-number@10.15.1.12:5060;transport=udp>
Then, 200 OK from Asterisk:
SIP/2.0 200 OK
*Via: SIP/2.0/UDP
10.15.1.30;rport=5060;received=10.15.1.30;branch=z9hG4bK1c02.7dc1b94be22d8780df5141f9ba3c5b7b.0
Via: SIP/2.0/UDP
10.15.1.12:5060;branch=z9hG4bKdd1m7b00aom47rggc700.1
*Record-Route: <sip:10.15.1.30;lr;ftag=SDkbo9901-42090>
Call-ID: SDkbo9901-71a1d17456b829b4c422af61de9eee7e-ao32g50
From: <sip:a-number@10.15.1.12;user=phone>;tag=SDkbo9901-42090
To:
<sip:mynumber@10.15.1.30>;tag=2e3c2071-c895-4069-afc2-37a19b20637a
CSeq: 1 INVITE
Server: Asterisk PBX 13.8.0
Contact: <sip:10.15.1.34:5060>
Which is sent to the SBC like this:
SIP/2.0 200 OK
Via: SIP/2.0/UDP
10.15.1.12:5060;branch=z9hG4bKdd1m7b00aom47rggc700.1
*Record-Route: <sip:10.15.1.30;lr;ftag=SDkbo9901-42090>
Call-ID: SDkbo9901-71a1d17456b829b4c422af61de9eee7e-ao32g50
From: <sip:a-number@10.15.1.12;user=phone>;tag=SDkbo9901-42090
To:
<sip:mynumber@10.15.1.30>;tag=2e3c2071-c895-4069-afc2-37a19b20637a
CSeq: 1 INVITE
Server: Asterisk PBX 13.8.0
Contact: <sip:10.15.1.34:5060>
And finally the SBC sends the ACK:
ACK sip:10.15.1.30:5060 SIP/2.0
Via: SIP/2.0/UDP
10.15.1.12:5060;branch=z9hG4bKdt7p9k00dounet8ic600.1
To:
<sip:mynumber@10.15.1.30>;tag=2e3c2071-c895-4069-afc2-37a19b20637a
From: <sip:a-number@10.15.1.12;user=phone>;tag=SDkbo9901-42090
Call-ID: SDkbo9901-71a1d17456b829b4c422af61de9eee7e-ao32g50
CSeq: 1 ACK
Contact: <sip:a-number@10.15.1.12:5060;transport=udp>
*Route: sip:10.15.1.30;lr;ftag=SDkbo9901-42090
<sip:10.15.1.30;lr;ftag=SDkbo9901-42090>
The problem: this ACK gets not retransmitted to Asterisk
At first, I thought it was some sanity check but after disabling that
I realized that it was in the WITHINDLG route.
For the incoming ACK I get in the logs:
Jun 8 11:56:47 tone-0866-fe-2-qa /usr/local/sbin/kamailio[53240]:
ALERT: <script>: Inside LOOSE route for ACK proto=UDP trans=4194304
from=sip:00754112601@10.15.1.12;user=phone
route=sip:10.15.1.30;lr;ftag=SDkbo9901-42090 src_ip=10.15.1.12
And once the ACK is ready to be sent to Asterisk, the Route header has
been removed and no Record-Route has been added so it fails.
Jun 8 11:56:44 tone-0866-fe-2-qa /usr/local/sbin/kamailio[53238]:
INFO: rr [rr_mod.c:402]: pv_get_route_uri_f(): No route header present.
Jun 8 11:56:44 tone-0866-fe-2-qa /usr/local/sbin/kamailio[53238]:
ALERT: <script>: ACK does not match transaction!! proto=UDP
trans=4194304 from=sip:00754112601@10.15.1.12;user=phone route=
src_ip=10.15.1.30
My WITHINDLG route looks like this:
# Handle requests within SIP
dialogs
route[WITHINDLG] {
if (has_totag())
{
# sequential request withing a dialog
should
# take the path determined by
record-routing
if (loose_route())
{
if (is_method("BYE"))
{
xlog("L_ALERT","Inside LOOSE
route\n");
setflag(FLT_ACC); # do accounting
...
setflag(FLT_ACCFAILED); # ... even if the transaction
fails
}
if ( is_method("ACK") )
{
xlog("L_ALERT","Inside LOOSE route for ACK proto=$rP
trans=$mf from=$fu route=$route_uri src_ip=$si \n");
# ACK is forwarded
statelessy
route(NATMANAGE);
}
route(RELAY);
} else
{
if (is_method("SUBSCRIBE") && uri == myself)
{
# in-dialog subscribe
requests
route(PRESENCE);
exit;
}
if ( is_method("ACK") )
{
if ( t_check_trans() )
{
# no loose-route, but stateful
ACK;
# must be an ACK after a
487
# or e.g. 404 from upstream server
t_relay();
exit;
} else
{
# ACK without matching transaction ... ignore and
discard
xlog("L_ALERT","ACK does not match transaction!!
proto=$rP trans=$mf from=$fu route=$route_uri src_ip=$si \n");
exit;
}
}
sl_send_reply("404","Not
here");
}
exit;
}
}
Thanks for reading this J Any idea about how to validate the
transaction? t_check_trans is not being validated…
Cheers, Francisco.
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--
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http://www.asipto.com - http://www.kamailio.org
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