XGW.DTLS.OtpDemux (xgw v0.1.0)

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Patches Erlang/OTP's DTLS packet demux so XGW can share one UDP socket.

Why a patch is needed

Stock OTP DTLS assumes each connection owns a private :gen_udp socket. XGW deliberately multiplexes STUN, DTLS, and SRTP on one Listener socket (standard WebRTC demux). Outbound DTLS must therefore call XGW.DTLS.Transport instead of :gen_udp.send/4.

At application start, patch!/0 loads a drop-in dtls_packet_demux BEAM from XGW's ebin when present. If the file is missing, startup continues with stock OTP (suitable for environments that do not run shared-socket DTLS).

RFCs

  • RFC 7983 -- WebRTC demux model that motivates a shared UDP socket
  • RFC 9147 / RFC 6347 -- DTLS (OTP connection that must send on that socket)

Summary

Functions

patch!()

Reloads ebin/dtls_packet_demux.beam when present.

Functions

patch!()

@spec patch!() :: :ok

Reloads ebin/dtls_packet_demux.beam when present.

Always returns :ok. Load failures are logged and ignored so the host app can still boot (for example in test without the patched BEAM).