mirror of https://github.com/ipxe/ipxe.git
gPXE responds to duplicated ACKs with an immediate retransmission, which can lead to a sorceror's apprentice syndrome. It also responds to out-of-range (or old duplicate) ACKs with a RST, which can cause valid connections to be dropped. Fix the sorceror's apprentice syndrome by leaving the retransmission timer running (and so inhibiting the immediate retransmission) when we receive a potential duplicate ACK. This seems to match the behaviour of Linux observed via wireshark traces. Fix the RST issue by sending RST only on out-of-range ACKs that occur before the connection is fully established, as per RFC 793. These problems were exposed during development of the 802.11 wireless link layer; the 802.11 protocol has a failure mode that can easily cause duplicated packets. The fixes were tested in a controlled way by faking large numbers of duplicated packets in the rtl8139 driver. Originally-fixed-by: Joshua Oreman <oremanj@rwcr.net> |
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crypto | ||
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