On Tue, 2016-06-14 at 06:03 -0700, Eric Dumazet wrote: > On Tue, 2016-06-14 at 11:40 +0000, Eggert, Lars wrote: > > On 2016-06-14, at 13:28, Pavel Emelyanov <xe...@virtuozzo.com> wrote: > > > Andrey (in Cc) has played with TCP_REPAIR recently, I guess he can know > > > something. > > > > Thanks for CC'ing him. We looked a little bit more into this: > > > > When TCP_REPAIR is on, tcp_connect() directly calls tcp_finish_connect() > > before returning, passing NULL for skb, which causes sk_rx_dst_set() to be > > bypassed. Later, when TCP_REPAIR is being turned off, do_tcp_setsockopt() > > just does tcp_send_window_probe(), but apparently all the "dst" stuff is > > being bypassed then also, so the mss remains at TCP_MSS_DEFAULT. > > > > Lars > > What gives : > > sysctl net/ipv4/ip_no_pmtu_disc net/ipv4/tcp_mtu_probing >
Also, is it a regression ? Was this working better with an older linux version ?
