On Sun, Nov 24, 2019 at 07:10 AM CET, John Fastabend wrote: > Jakub Sitnicki wrote: >> This patch set makes SOCKMAP more flexible by allowing it to hold TCP >> sockets that are either in established or listening state. With it SOCKMAP >> can act as a drop-in replacement for REUSEPORT_SOCKARRAY which reuseport >> BPF programs use. Granted, it is limited to only TCP sockets. >> >> The idea started out at LPC '19 as feedback from John Fastabend to our >> troubles with repurposing REUSEPORT_SOCKARRAY as a collection of listening >> sockets accessed by a BPF program ran on socket lookup [1]. Without going >> into details, REUSEPORT_SOCKARRAY proved to be tightly coupled with >> reuseport logic. Talk from LPC (see slides [2] or video [3]) highlights >> what problems we ran into when trying to make REUSEPORT_SOCKARRAY work for >> our use-case. >> >> Patches have evolved quite a bit since the RFC series from a month ago >> [4]. To recap the RFC feedback, John pointed out that BPF redirect helpers >> for SOCKMAP need sane semantics when used with listening sockets [5], and >> that SOCKMAP lookup from BPF would be useful [6]. While Martin asked for >> UDP support [7]. > > Curious if you've started looking into UDP support. I had hoped to do > it but haven't got there yet. No, not yet. I only made sure the newly added tests were easy to modify to cover UDP by not hard-coding the socket type. I expect to break ground with UDP work soon, though. Right after I push out another iteration of programmable socket lookup [1] patches adapted for SOCKMAP, which we've been testing internally. >> As it happens, patches needed more work to get SOCKMAP to actually behave >> correctly with listening sockets. It turns out flexibility has its >> price. Change log below outlines them all. >> > > But looks pretty clean to me, only major change here is to add an extra > hook to remove psock from the child socket. And that looks fine to me and > cleaner than any other solution I had in mind. > > Changes +/- looks good as well most the updates are in selftests to update > tests and add some new ones. +1 Thanks for taking a look at the patches so quickly. I appreciate it. -Jakub [1] https://lore.kernel.org/bpf/20190828072250.29828-1-jakub@xxxxxxxxxxxxxx/
