if -b was given without a explicit host, it defaulted to listen on any address. it's not a good idea given this would allow anyone on the same network to (ab)use the ssh forwarding.

socket splicing allows to do zero-copy data transfers between sockets. This adds a specific implementation for OpenBSD using the setsockopt SO_SPLICE and a default implementation with libevent (that is the old code doing the copy in userland.) It's possible to do the same on linux with splice(2), not implementd though.

errno doesn't contain anything useful in this case

otherwise we may end up in a weird state where we're counting connections that we don't have or have cleared a timeout without a reason.

it should call conn_free to cleanup the connection struct now.