[asterisk-bugs] [JIRA] (ASTERISK-27421) RTP source learning not working with devices that have some clock issues

[nappsoft (JIRA)]

nappsoft created ASTERISK-27421:
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             Summary: RTP source learning not working with devices that have some clock issues
                 Key: ASTERISK-27421
                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-27421
             Project: Asterisk
          Issue Type: Bug
      Security Level: None
          Components: Resources/res_rtp_asterisk
    Affects Versions: 13.18.2
            Reporter: nappsoft
            Severity: Minor


I've observed some Softphones that do not send packets perfectly frequent but for example with 30ms between the first and the second packets and <1 ms between the second and the third. While a jitterbuffer can handle this perfectly, the strict learning algorithm doesn't accept that: it will reset the learning process on every third packet as there are less than 5 ms between these packets.

I've attached a patch that is changing the implementation in a way that not the time between two packets is taken into account to detect a flood, but the time between the first and the last packet during the learning phase. (A timeout lower than 30ms between 4 packets will not be accepted) what solves the described issue and will still detect flood attacks.



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