| Message ID | 160582070138.66684.11785214534154816097.stgit@localhost.localdomain (mailing list archive) |
|---|---|
| Headers | show |
| Series | tcp: Address issues with ECT0 not being set in DCTCP packets | expand |
On Thu, 19 Nov 2020 13:23:43 -0800 Alexander Duyck wrote: > This patch set is meant to address issues seen with SYN/ACK packets not > containing the ECT0 bit when DCTCP is configured as the congestion control > algorithm for a TCP socket. > > A simple test using "tcpdump" and "test_progs -t bpf_tcp_ca" makes the > issue obvious. Looking at the packets will result in the SYN/ACK packet > with an ECT0 bit that does not match the other packets for the flow when > the congestion control agorithm is switch from the default. So for example > going from non-DCTCP to a DCTCP congestion control algorithm we will see > the SYN/ACK IPV6 header will not have ECT0 set while the other packets in > the flow will. Likewise if we switch from a default of DCTCP to cubic we > will see the ECT0 bit set in the SYN/ACK while the other packets in the > flow will not. Applied, thanks!
This patch set is meant to address issues seen with SYN/ACK packets not containing the ECT0 bit when DCTCP is configured as the congestion control algorithm for a TCP socket. A simple test using "tcpdump" and "test_progs -t bpf_tcp_ca" makes the issue obvious. Looking at the packets will result in the SYN/ACK packet with an ECT0 bit that does not match the other packets for the flow when the congestion control agorithm is switch from the default. So for example going from non-DCTCP to a DCTCP congestion control algorithm we will see the SYN/ACK IPV6 header will not have ECT0 set while the other packets in the flow will. Likewise if we switch from a default of DCTCP to cubic we will see the ECT0 bit set in the SYN/ACK while the other packets in the flow will not. --- Alexander Duyck (2): tcp: Allow full IP tos/IPv6 tclass to be reflected in L3 header tcp: Set INET_ECN_xmit configuration in tcp_reinit_congestion_control net/ipv4/tcp_cong.c | 5 +++++ 1 file changed, 5 insertions(+) --