This removes all the channel-closure stuff from handle_error!() and
MsgHandleErrInternal, making all the Err handling consistent by
closing the channel before releasing the channel_state lock and
then calling handle_error!() outside of the lock.
Technically funding_transaction_generated was fine using it, but
calling force_shutdown on an empty Channel inside the channel_state
lock isn't a big deal and almost any other use of it would be
unsafe.
If we never accessed channels for a peer outside of a message
handler for that peer then this wouldn't be a problem since message
handlers are required to be serialized per-peer. However, that
isn't the world we live in - we may want to forward payments or we
may get a send_payment call.
This converts block_connected failures to returning the
ErrorMessage that needs to be sent directly, since it always
results in channel closure and never results in needing to call
force_shutdown. It also converts update_add_htlc and closing_signed
handlers to ChannelError as the rest of the message handlers.
Currently channel_reserve_test sends a garbage update_add_htlc
message and then relies on it being silently ignored to continue
using the channel. This shouldn't be the case, so take the easy
way out and split the test in two, at first not delivering the
bogus update_add_htlc and then delivering it, but not running the
rest of the test.
This is a big patch, but its all very mechanical, everything here
should be pretty obvious, and it all has to happen at once due to a
few common utility functions all having the same return type.
Note that this exposes a race in channel closure where we may
access a channel via some non-peer-specific mechanism like
forwarding an HTLC or sending a payment during the time between
the channel gave us a Close error and expected us to never call it
again and the time we actually removed it from the channel_state
set outside of the internal_* handler.
This fixes a bug in 78232f2aed found
by fuzzer - if the channel isn't yet fully established we will call
get_channel_update(), get an Err result, and then unwrap() it. If
this actually happens it means someone on the network is making up
short_channel_ids and trying to route over them, but that shouldn't
result in us crashing
During normal operation we should never need to take this, so we
use a RwLock that allows normal parallelism until we want to
serialize out our ChannelManager, at which point we can take the
write-mode lock.
