hi folks I've run into a few cases where users have wanted to enable additional tcp-bpf sock_ops events for a socket _after_ connection establishment. The problem is that to set the flags to enable additional events, we have to be in the context of a sock_ops program, and as I understand it, by default only events early in the socket lifetime are enabled by default (such as connection established/accepted). As a consequence, if we do not catch one of those early events, the sock_ops program will not run and we miss the opportunity to enable more sock_ops events. This can be a problem for boot-time connections like iSCSI where we are too late to catch connection establishment. I can see a few possibilities: - support setting sock_ops event flags via a socket iterator. This would mean that the user can always set per-socket flags on already-established sockets by iterating over existing sockets, selecting those of interest. - supporting setting event flags via setsockopt(). In fact we wouldn't need to fully support setting event flags via "real" setsockopt(); we could simply use a cgroup/setsockopt program and allow bpf_sock_ops_cb_flags_set() to run in the cgroup/setsockopt context (with additional checks to ensure it is indeed a tcp socket). Do either/both of these seem reasonable, or is there a better way to tackle this? Thanks! Alan
