Asterisk
  1. Asterisk
  2. ASTERISK-26923

bridging: T.38 request is lost when channels are added to bridge

    Details

    • Frequency of Occurrence:
      Frequent

      Description

      The B leg of a call gets established before the A leg does. If the B party sends a T.38 re-invite immediately, the T38_CONTROL frame can get lost as the B party has joined the Bridge and the A party as not yet joined the bridge

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          Hide
          Torrey Searle added a comment -

          also can you elaborate a bit more on the deadlock? from what I see ast_channel_make_compatible also acquires the channel locks, so why is the former unsafe and the latter safe exactly?

          Torrey

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          Torrey Searle added a comment - also can you elaborate a bit more on the deadlock? from what I see ast_channel_make_compatible also acquires the channel locks, so why is the former unsafe and the latter safe exactly? Torrey
          Hide
          Richard Mudgett added a comment -

          The channel locks are subordinate to bridge locks in the locking order. You can lock a bridge lock then lock a channel lock without doing deadlock avoidance. To lock a channel lock then a bridge lock you have to do deadlock avoidance since you are going up the locking hierarchy.

          There is a locking precedence order diagram on this page: https://wiki.asterisk.org/wiki/display/AST/Asterisk+12+Bridging+Project

          Show
          Richard Mudgett added a comment - The channel locks are subordinate to bridge locks in the locking order. You can lock a bridge lock then lock a channel lock without doing deadlock avoidance. To lock a channel lock then a bridge lock you have to do deadlock avoidance since you are going up the locking hierarchy. There is a locking precedence order diagram on this page: https://wiki.asterisk.org/wiki/display/AST/Asterisk+12+Bridging+Project
          Hide
          Rusty Newton added a comment -

          Torrey Searle or Richard Mudgett do you think this issue ASTERISK-26948 could be related to this issue?

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          Rusty Newton added a comment - Torrey Searle or Richard Mudgett do you think this issue ASTERISK-26948 could be related to this issue?
          Hide
          Torrey Searle added a comment -

          Rusty Newton I had a look at the pcaps of the other jira & I see that the T.38 re-invite is getting forwarded. In this jira, the control frame to instruct the other leg to send a re-invite gets lost.

          So I don't think these two are related.

          Show
          Torrey Searle added a comment - Rusty Newton I had a look at the pcaps of the other jira & I see that the T.38 re-invite is getting forwarded. In this jira, the control frame to instruct the other leg to send a re-invite gets lost. So I don't think these two are related.
          Hide
          Rusty Newton added a comment -

          Torrey Searle thanks for your input!

          Show
          Rusty Newton added a comment - Torrey Searle thanks for your input!

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              • Created:
                Updated:
                Resolved:

                Development