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See this thread for more details. Main point:

When we authenticate for the purposes of a SIP session (when credentials are not being cached), the following happens:

  • client -> livekit : I want to start a call (INVITE)
  • client <- livekit : You need to authenticate (SIP-407 Unauthorized).
    • This may count as a failure.
    • The 407 response contains an auth challenge.
  • client -> livekit : I want to start a call (INVITE), this time with the credentials.
    • This call has the exact same callid as the first one.
    • It also contains the auth response.
  • client -> livekit : credentials look good, I'll forward your call request (SIP-100 Trying).

If we happen to count the 407 response as a failed call, and we generate unique SCL_* ids for both.

@alexlivekit alexlivekit requested a review from a team as a code owner October 20, 2025 21:30
inviteOKRetryAttemptsNoACK = 2
inviteOkAckLateTimeout = inviteOkRetryIntervalMax

inviteCredentialValidity = 60 * time.Minute // Allow reuse of credentials for 1h
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Not sure this is smart, might want to extend this to max_call_duration or something.

Also, keep in mind that this is per Call-ID for now, so new calls would still need re-auth.

tr := callTransportFromReq(req)
legTr := legTransportFromReq(req)
log := s.log.WithValues(
"callID", callID,
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The one log line that will not have callID now is "Bad request", when validation fails.

@alexlivekit alexlivekit changed the title Reuse the same ID for both auth-less and auth-ful INVITEs TEL-222: Reuse the same ID for both auth-less and auth-ful INVITEs Oct 20, 2025
if err != nil {
return nil, fmt.Errorf("invalid challenge %q: %w", challengeStr, err)
}
toHeader := resp.To()
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@alexlivekit alexlivekit Oct 20, 2025

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Now that we're doing the right validation on the inbound side, the outbound side E2E test caught this error!
But this also means out clients might run into the same issue, in case some of them are not spec-compliant.

log: log,
s: s,
id: id,
id: "unassigned",
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Would be helpful if it logs/panics if something tries to read this unassigned ID.

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I would rather not add shims or verification for this. Unless it's real clean, I'd rather leave it blank. Would that be better in your opinion?

@alexlivekit alexlivekit changed the title TEL-222: Reuse the same ID for both auth-less and auth-ful INVITEs Reuse the same ID for both auth-less and auth-ful INVITEs Oct 21, 2025
@alexlivekit alexlivekit marked this pull request as draft October 22, 2025 23:33
@alexlivekit alexlivekit marked this pull request as ready for review October 23, 2025 07:45
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3 participants