On Tue, Mar 10, 2020 at 06:47 PM CET, Lorenz Bauer wrote:
> We want to use sockhash and sockmap to build the control plane for
> our upcoming BPF socket dispatch work. We realised that it's
> difficult to resize or otherwise rebuild these maps if needed,
> because there is no way to get at their contents. This patch set
> allows a privileged user to retrieve fds from these map types,
> which removes this obstacle.
Since it takes just a few lines of code to get an FD for a sock:
fd = get_unused_fd_flags(O_CLOEXEC);
if (unlikely(fd < 0))
return fd;
fd_install(fd, get_file(sk->sk_socket->file));
... I can't help but wonder where's the catch?
IOW, why wasn't this needed so far?
How does Cilium avoid resizing & rebuilding sockmaps?
Just asking out of curiosity.
[...]
