Bug#920533: asterisk: on upgrade from 13.23.1 to 16.1.1 RTP streams get misdirected to NAT devices

[James.Bottomley at HansenPartnership.com]

Package: asterisk
Version: 1:16.1.1~dfsg-1
Severity: important

The symptom is that NAT connected devices can't send or receive audio
tcpdump shows the asterisk server is sending audio to the RTP header address,
which is behind the NAT instead of the NAT gateway address.

Further debugging shows that __ast_read() is never actually getting to
the ast_rtp_read() function because __ast_read() always has an
AST_TIMER_EVENT_EXPIRED so the RTP nat detection and setup is never called
because we technically have never received an RTP packet from the remote.

I've fixed this in my local installation by setting the RTP remote address
to the sip remote address if chan_sip detects a nat, but this seems
to be a timer problem so this fix is likely only papering it over.


-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing'), (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 4.19.0-1-686 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages asterisk depends on:
ii  adduser                  3.118
ii  asterisk-config          1:16.1.1~dfsg-1
ii  asterisk-core-sounds-en  1.6.1-1
ii  asterisk-modules         1:16.1.1~dfsg-1
ii  libc6                    2.28-5
ii  libcap2                  1:2.25-1.2
ii  libedit2                 3.1-20181209-1
ii  libgcc1                  1:8.2.0-14
ii  libjansson4              2.12-1
ii  libpopt0                 1.16-11
ii  libsqlite3-0             3.26.0+fossilbc891ac6b-1
ii  libssl1.1                1.1.1a-1
ii  libsystemd0              240-4
ii  liburiparser1            0.9.1-1
ii  libuuid1                 2.33.1-0.1
ii  libxml2                  2.9.4+dfsg1-7+b3
ii  libxslt1.1               1.1.32-2
ii  lsb-base                 10.2018112800

Versions of packages asterisk recommends:
ii  asterisk-moh-opsound-gsm                         2.03-1
ii  asterisk-voicemail [asterisk-voicemail-storage]  1:16.1.1~dfsg-1
ii  sox                                              14.4.2-3

Versions of packages asterisk suggests:
pn  asterisk-dahdi   <none>
ii  asterisk-dev     1:16.1.1~dfsg-1
ii  asterisk-doc     1:16.1.1~dfsg-1
pn  asterisk-ooh323  <none>
pn  asterisk-opus    <none>
pn  asterisk-vpb     <none>

-- no debconf information

-- debsums errors found:
debsums: changed file /usr/sbin/asterisk (from asterisk package)