<div dir="ltr">Now that I'm finished tripping over my own mistakes, and it appears to be working well, I'll document it in case someone else has the same application with the same cranky CPE devices.<div><br></div><div>On the initial request, I save the caller contact before any nathelper modules change it:</div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><font size="1" face="monospace">$var(ct_uri) = $(ct.fields(uri){nameaddr.uri});</font></div></blockquote><div><br></div><div>After the dialog is created (by <font face="monospace" size="1">topology_hiding()</font> in my case), I stuff this value into the dialog:<br></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><font face="monospace" size="1">$dlg_val(caller_private_contact) = $var(ct_uri);</font></div></blockquote><div><br></div><div>In my case I have multiple registered contacts per AOR, so I have this in the branch_route:</div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><font face="monospace" size="1">$bavp(callee_private_contact) = $ru;</font></div></blockquote><div><br></div><div>Then, in onreply_route, I stuff the dialog value with the original contact of the willing branch:</div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><font face="monospace" size="1">if (t_check_status("200")) {</font></div><div><font face="monospace" size="1"> $dlg_val(callee_private_contact) = $bavp(callee_private_contact);</font></div><div><font face="monospace" size="1">}</font></div></blockquote><div><br></div><div>At this point the dialog has the original callee and caller values.</div><div><br></div><div>In the section that handles sequential requests (beneath <font size="1" face="monospace">topology_hiding_match()</font> in my case), I have basically what Răzvan suggested:</div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><span style="font-family:monospace;font-size:x-small">$du = $ru;</span></div><div><font face="monospace" size="1">if ($DLG_dir == "upstream") {</font></div><div><font face="monospace" size="1"> $ru = $dlg_val(caller_private_contact);</font></div><div><font face="monospace" size="1">} else {</font></div><div><font face="monospace" size="1"> $ru = $dlg_val(caller_private_contact);</font></div><div><font face="monospace" size="1">}</font></div></blockquote><div><br></div><div>And voilà, <font face="monospace" size="1">$du</font> preserves the routing destination while <font size="1" face="monospace">$ru</font> contains the original contact before NAT mangling. Excellent.</div><div><br></div><div><br></div><div>- Jeff</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Feb 5, 2021 at 2:58 PM Jeff Pyle <<a href="mailto:jeff@ugnd.org">jeff@ugnd.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">This makes sense. I've been able to store the values, but I'm still experimenting with the right times to restore them. Thanks, Răzvan.<div><br></div><div><br></div><div><br></div><div>- Jeff</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Feb 4, 2021 at 10:04 AM Răzvan Crainea <<a href="mailto:razvan@opensips.org" target="_blank">razvan@opensips.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi, Jeff!<br>
<br>
The only way to achieve this is to do it manually: store the contact on <br>
the request/replies in a dialog variable, and *after* <br>
topology_hiding_match(), set each of them:<br>
<br>
$du = $ru;<br>
if ($DLG_dir == "downstream") {<br>
$ru = $dlg_val(caller_private_contact);<br>
} else {<br>
$ru = $dlg_val(callee_private_contact);<br>
}<br>
<br>
Hope this helps,<br>
<br>
Răzvan Crainea<br>
OpenSIPS Core Developer<br>
<a href="http://www.opensips-solutions.com" rel="noreferrer" target="_blank">http://www.opensips-solutions.com</a><br>
<br>
On 1/26/21 6:36 PM, Jeff Pyle wrote:<br>
> Hi Johan,<br>
> <br>
> There typically isn't loose_route() in my script because there <br>
> is topology_hiding_match() instead. But, I've tested without topology <br>
> hiding (using loose_route for sequential requests) and there is no <br>
> difference.<br>
> <br>
> The docs for fix_route_dialog() <br>
> <<a href="https://opensips.org/html/docs/modules/3.1.x/dialog.html#func_fix_route_dialog" rel="noreferrer" target="_blank">https://opensips.org/html/docs/modules/3.1.x/dialog.html#func_fix_route_dialog</a>> <br>
> say that it "forces an in dialog SIP message to contain the ruri, route <br>
> headers and dst_uri, as specified by the internal data of the dialog it <br>
> belongs to." That's not a problem here; the in-dialog request already <br>
> has the same values as the internal data of the dialog it belongs to. <br>
> This function looks more to prevent bad actors from doing nasty things <br>
> in in-dialog requests. In my case everyone is playing by the rules.<br>
> <br>
> The caller_contact and callee_contact from the "internal data of the <br>
> dialog" (as viewed with the dlg_list MI command) contain the <br>
> public/received IP and port rather than the internal/private IP and port <br>
> each UA provided. That occurs because of the fix_nated_contact() <br>
> function in the script prior to dialog creation. In other words, by the <br>
> time the dialog is created, the internal IP:port is lost.<br>
> <br>
> My questions are:<br>
> - how to preserve the private/internal Contact info in the dialog, and<br>
> - use it for signaling in the RURI but continue to use the <br>
> received/public info for routing for in-dialog requests<br>
> <br>
> <br>
> - Jeff<br>
> <br>
> On Tue, Jan 26, 2021 at 11:04 AM Johan De Clercq <<a href="mailto:Johan@democon.be" target="_blank">Johan@democon.be</a> <br>
> <mailto:<a href="mailto:Johan@democon.be" target="_blank">Johan@democon.be</a>>> wrote:<br>
> <br>
> did you change the loose route part to fix route dialog ?<br>
> <br>
> Op di 26 jan. 2021 om 16:39 schreef Jeff Pyle <<a href="mailto:jeff@ugnd.org" target="_blank">jeff@ugnd.org</a><br>
> <mailto:<a href="mailto:jeff@ugnd.org" target="_blank">jeff@ugnd.org</a>>>:<br>
> <br>
> Hello,<br>
> <br>
> This is on OpenSIPS nightly 3.1.1~20210125~8bab0da7b-1.<br>
> <br>
> I have a registrar configured with basic call routing between<br>
> the registered AORs. I use topology_hiding("D") to create the<br>
> dialog on calls and normal stuff like has_totag()<br>
> and topology_hiding_match() for sequential request handling. <br>
> All this seems fine.<br>
> <br>
> This appears high in the main route and appears to do exactly<br>
> what it should:<br>
> <br>
> if (has_body("application/sdp")) {<br>
> if (nat_uac_test(14)) {<br>
> setflag("NAT_FLAG");<br>
> }<br>
> } else {<br>
> if (nat_uac_test(6)) {<br>
> setflag("NAT_FLAG");<br>
> }<br>
> }<br>
> <br>
> if (isflagset("NAT_FLAG")) {<br>
> force_rport();<br>
> if ($rm == "REGISTER") {<br>
> fix_nated_register();<br>
> } else {<br>
> fix_nated_contact();<br>
> }<br>
> }<br>
> <br>
> And, for replies:<br>
> <br>
> onreply_route [handle_rtprelay_onreply] {<br>
> # rtpengine and such, omitted for brevity<br>
> if (isbflagset("NAT_BFLAG")) {<br>
> fix_nated_contact();<br>
> }<br>
> <br>
> exit;<br>
> }<br>
> <br>
> When one client calls another, everything works<br>
> fine. lookup("location") works to update $rd with the original<br>
> (private) Contact provided upon registration, and $du contains<br>
> the actual received source IP:port to get to the device. <br>
> Excellent. The INVITE goes out accordingly, and all is well.<br>
> <br>
> My problem occurs with sequential requests, say, re-INVITEs from<br>
> on-hold events. The dialogs themselves save the received<br>
> IP:port values as the caller_contact and callee_contact values<br>
> (from fix_nated_contact() above), so when the requests pass<br>
> through the sequential handling section of the script<br>
> and topology_hiding_match() does its fixups, the request URI<br>
> domain of the relayed request has the received IP:port values of<br>
> the target UA rather than the private IP:port values the UA<br>
> provided during the initial request that established the dialog.<br>
> <br>
> I can't wrap my head around how to fix this. The initial<br>
> requests work because lookup() has the intelligence to<br>
> distinguish the UAC's Contact from the received IP:port at<br>
> REGISTER-time, but I can't see how to achieve this at<br>
> dialog-creation time so sequential requests have the right RURI<br>
> domain. Force the caller_contact and callee_contact to the<br>
> private values somehow, and manage the route_set to point to the<br>
> appropriate received IP:port? I'm not sure how to configure<br>
> that if it is the solution.<br>
> <br>
> Any direction would be appreciated!<br>
> <br>
> <br>
> Regards,<br>
> Jeff<br>
> <br>
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</blockquote></div>