fix(coap-server): ignore incoming requests with an invalid source port

[JKRhb]

Resolves #1182.

This is more like a workaround for now to fix the crashes immediately but should be fixed at the library level eventually.

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (be1fd88) 76.66% compared to head (ba92879) 76.65%.
Report is 7 commits behind head on master.

Files	Patch %	Lines
packages/binding-coap/src/coap-server.ts	50.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1188      +/-   ##
==========================================
- Coverage   76.66%   76.65%   -0.02%     
==========================================
  Files          80       80              
  Lines       16813    16821       +8     
  Branches     1618     1619       +1     
==========================================
+ Hits        12890    12894       +4     
- Misses       3893     3897       +4     
  Partials       30       30              

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[relu91]

What happens to the ignored request? Do clients try to send another request? Also I'd add a followup issue to revert the change once it is solved in node-coap.

[JKRhb]

What happens to the ignored request? Do clients try to send another request?

If the request is confirmable, then clients will try to retransmit it until it has timed out. Usually, you could inform them that their request was unable to be processed by sending a reset message – but in this case, that is not possible as we would be running into the same problem again :/

Also I'd add a followup issue to revert the change once it is solved in node-coap.

That sounds good!

[relu91]

good to go.

[danielpeintner]

Also I'd add a followup issue to revert the change once it is solved in node-coap.

That sounds good!

Created #1190

[danielpeintner]

LGTM, just a suggestion see below...

Since it is a temporary fix I am okay either way