Bugzilla – Bug 438
csma helper hooks the transmit queue enqueue operation for pcap tracing
Last modified: 2009-02-28 19:38:52 EST
Hooking the transmit queue enqueue is not what I would have expected at all. That makes it appear that the packet went on the wire when the packet was enqueued. The packet is actually sent after it is dequeued. I think the helper should hook the dequeue trace hook for pcap tracing since there can be a significant delta-t between the enqueue and the dequeue. Perhaps even better, there should be a new low-level trace hook Tx that corresponds to a packet being sent out to the channel. Right now there is a hole where a packet can be dequeued from the transmit queue and subsequently silently dropped. This makes it appear as if the packet was transmitted successfully. I think it would be better to have upper level trace hooks into the transmit queue, and lower level trace hooks at the device/channel interface. Right now things are mixed and somewhat confused/confusing.
*** This bug has been marked as a duplicate of bug 443 ***