How to configure freeSWITCH for a docker container inside boot2docker? - docker

Question

I'm trying to setup a Docker container running freeSWITCH so I can deploy it on a Debian server.
For developing, I use a Mac running the freeSWITCH container within boot2docker.
I need the container to work in both these environments.
I manage to connect to the FS server with a softphone and place a call but after 32 seconds, the call drops.
freeswitch#internal> version
FreeSWITCH Version 1.4.15-1~64bit (-1 64bit)
This is the SIP 200 OK packet that FS sends and expects an answer to:
14 0.029449000 192.168.59.103 192.168.59.3 SIP/SDP 1312 Status: 200 OK |
SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.1.141:49822;rport=49822;branch=z9hG4bKPjFf3iaNQ0tDY1fySiz1zGSEXSVFpZeE2b;received=192.168.59.3
From: "1000" <sip:1000#192.168.59.103>;tag=tNpJHmkYg0ke5GYyvIhkdBSIMM.ujzXE
To: <sip:5000#192.168.59.103>;tag=6N3793jeayeUe
Call-ID: 4wWTcxr9Q4OqlgT2Fs-8SeOkLhVYXTLb
CSeq: 10007 INVITE
Contact: <sip:5000#172.17.0.6:5060;transport=udp>
User-Agent: FreeSWITCH-mod_sofia/1.4.15-1~64bit
Accept: application/sdp
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
Supported: timer, path, replaces
Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer
Content-Type: application/sdp
Content-Disposition: session
Content-Length: 333
Remote-Party-ID: "5000" <sip:5000#192.168.59.103>;party=calling;privacy=off;screen=no
v=0
o=FreeSWITCH 1422731206 1422731207 IN IP4 172.17.0.6
s=FreeSWITCH
c=IN IP4 172.17.0.6
t=0 0
m=audio 16386 RTP/SAVP 9 101
a=rtpmap:9 G722/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20
a=rtcp:16387 IN IP4 172.17.0.6
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:/NTeSA7Od0+1Uo1/3wIclZwEiKJ+R4Mh8gyTx+5O
Then this happens:
1745 32.031059000 192.168.59.103 192.168.59.3 SIP 664 Request: BYE sip:29716085#192.168.59.3:49822 |
BYE sip:29716085#192.168.59.3:49822 SIP/2.0
Via: SIP/2.0/UDP 172.17.0.6;rport;branch=z9hG4bK0m429X0ac150r
Max-Forwards: 70
From: <sip:5000#192.168.59.103>;tag=6N3793jeayeUe
To: "1000" <sip:1000#192.168.59.103>;tag=tNpJHmkYg0ke5GYyvIhkdBSIMM.ujzXE
Call-ID: 4wWTcxr9Q4OqlgT2Fs-8SeOkLhVYXTLb
CSeq: 71037748 BYE
Contact: <sip:5000#172.17.0.6:5060;transport=udp>
User-Agent: FreeSWITCH-mod_sofia/1.4.15-1~64bit
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
Supported: timer, path, replaces
Reason: SIP;cause=408;text="ACK Timeout"
Content-Length: 0
I'm guessing FS never receives an answer from the softphone because of the various NAT layers and drops the call, assuming it didn't connect.
192.168.1.141 is my Mac's IP address on the LAN (as shown in the VIA for the 200 OK packet)
192.168.59.103 is the boot2docker VM
192.168.59.3 is my Mac on the boot2docker virtual network
172.17.0.xxx is the FS server's IP address on the Docker network (this IP changes, depending on how many containers are/were running before)
This is what I have on my sip_profiles/internal.xml
<param name="rtp-ip" value="$${local_ip_v4}"/>
<!-- ip address to bind to, DO NOT USE HOSTNAMES ONLY IP ADDRESSES -->
<param name="sip-ip" value="$${local_ip_v4}"/>
<param name="hold-music" value="$${hold_music}"/>
<param name="apply-nat-acl" value="nat.auto"/>
<!-- Docker NAT magic -->
<param name="ext-sip-ip" value="$${external_sip_ip}"/>
<param name="ext-rtp-ip" value="$${external_rtp_ip}"/>
And in my vars.xml
<X-PRE-PROCESS cmd="set" data="external_rtp_ip=192.168.59.103"/>
<X-PRE-PROCESS cmd="set" data="external_sip_ip=192.168.59.103"/>
From fs_cli:
freeswitch#internal> eval ${external_rtp_ip}
192.168.59.103
freeswitch#internal> eval ${external_sip_ip}
192.168.59.103
freeswitch#internal> eval ${ext-rtp-ip}
-ERR no reply
freeswitch#internal> eval ${ext-sip-ip}
-ERR no reply
I have set ports 16384 to 16484 UDP for RTP traffic, 5060, 5070, 5080 UDP & TCP for SIP, both in FS and in the container.
An echo test reveals that audio flows both ways.
Any idea what is happening and how to fix?

Answer 1

I had a similar problem with my FreeSwitch installation and I solved it by configuring the switch to constantly ping the registered softphones so as to keep the NAT firewall channels open. Here are the settings that did it for me:
<param name="nat-options-ping" value="true"/>
<param name="all-reg-options-ping" value="true"/>
<!-- One successful options ping is enough to verify that a phone is reachable -->
<param name="sip-user-ping-min" value="1"/>
<!-- Three pings need to be lost to consider the phone disconnected -->
<param name="sip-user-ping-max" value="4"/>
<param name="unregister-on-options-fail" value="true"/>
<!-- Freeswitch is coded to send
pings at variable intervals with the mean value determined by the
variable below and a normal distribution with a deviation of half the
interval value. -->
<param name="ping-mean-interval" value="15"/>
They go to sip_profiles/internal.xml.

Answer 2

Ok so here is an update.
It turns out the problem was because FS wasn't able to detect its IP properly and the packets it was sending back contained to the wrong IP.
I came up with this script as part of my container boot sequence:
https://github.com/Coaxial/mushimushi/blob/a29ae537314e89bc7f9808c2bd7fdb4917eafa04/lib/freeswitch_conf/start.sh#L7-L21
I then include the resulting XML file into the general config: https://github.com/Coaxial/mushimushi/blob/a29ae537314e89bc7f9808c2bd7fdb4917eafa04/lib/freeswitch_conf/freeswitch.xml#L3
This way I can reference the variables to configure the relevant Sofia profiles: https://github.com/Coaxial/mushimushi/blob/a29ae537314e89bc7f9808c2bd7fdb4917eafa04/lib/freeswitch_conf/autoload_configs/sofia.conf.xml#L29-L32
This works when run in boot2docker but isn't battle tested in "vanilla" docker yet.