channeledtransport: fix segfault during callback destruction

onDestroy/onRecv should not be called after destruction. Because
ChanneledSIPTransport is managed by PJSIP, we can't pass a weak_ptr to the
callbacks, so just replace the callbacks during the destruction.

Change-Id: Ibc3f2baf8b4cdcfe45652fd14d1acc9d38a07af4

src/jamidht/channeled_transport.cpp

@@ -155,6 +155,10 @@ ChanneledSIPTransport::~ChanneledSIPTransport()
 
     auto base = getTransportBase();
 
+    // Here, we reset callbacks in ChannelSocket to avoid to call it after destruction
+    // ChanneledSIPTransport is managed by pjsip, so we don't have any weak_ptr available
+    socket_->setOnRecv([](const uint8_t* buf, size_t len){return len;});
+    socket_->onShutdown([](){});
     // Stop low-level transport first
     socket_->shutdown();
     socket_.reset();