Asterisk hangs with "Too many open files"

[Stell0]

When someone from external try to make an anonymous call, is sent to this piece of dialplan

exten => s,n,Log(WARNING,"Rejecting unknown SIP connection from ${CHANNEL(${receveip})}")
exten => s,n,Answer
exten => s,n,Wait(2)
exten => s,n,Playback(ss-noservice)
exten => s,n,Playtones(congestion)
exten => s,n,Hangup

That plays an audio message than hangup the call. Since beginning of september,a different kind of SIP requests started to be seen in the wild, which response seems to be tied to ipv6 addresses. It is still not completely clear why, but the UDP file descriptor tied to the audio response of this request remains open, and the result is that after a while asterisk hangs with "Too main open files" error message

There are two workarounds:

• remove IPv6 address from interfaces
• hangup the anonymous call before opening the audio channel

Steps to reproduce

There isn't a clear way to reproduce this at the moment

Expected behavior

UDP file descriptor should be closed at the end of the call

Actual behavior

UDP file descriptors remains open till Asterisk resources are saturated

[Stell0]

not the first time that we find problems here https://github.com/nethesis/dev/issues/6183

[Stell0]

in 7.9.2009/nethesis-testing:

• nethserver-nethvoice14-14.18.4-1.2.g1977384.ns7.noarch.rpm x86_64

[nethbot]

in 7.9.2009/nethesis-updates:

• nethserver-nethvoice14-14.18.5-1.ns7.noarch.rpm x86_64