Invalid protocol state (with squid)

netarch / neo

A network testing tool combining formal model checking and container-based emulation that covers in-network non-determinism

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Invalid protocol state (with squid) #21

Open kyechou opened 1 year ago

kyechou commented 1 year ago

example 04 Output: https://hastebin.com/xekogugijo

kyechou commented 1 year ago

The problem was caused by the proxy trying to re-establish new connections to the server after the proxy has sent out a FIN-ACK packet but before the server replies with FIN-ACK or the previous connection terminates.

kyechou commented 1 year ago

Potential solution(?):

When this kind of error (pkt.proto_state() < model.proto_state()) happens, rewind the emulation again to reset their internal timer.
Also, if we can pause and then later resume the emulation, that may also solve the issue.

kyechou commented 1 year ago

SIGSTOP, SIGCONT https://major.io/2009/06/15/two-great-signals-sigstop-and-sigcont/