Long ago, we used the `no_connection_possible` to signal that a
peer has some unknown feature set or some other condition prevents
us from ever connecting to the given peer. In that case we'd
automatically force-close all channels with the given peer. This
was somewhat surprising to users so we removed the automatic
force-close, leaving the flag serving no LDK-internal purpose.
Distilling the concept of "can we connect to this peer again in the
future" to a simple flag turns out to be ripe with edge cases, so
users actually using the flag to force-close channels would likely
cause surprising behavior.
Thus, there's really not a lot of reason to keep the flag,
especially given its untested and likely to be broken in subtle
ways anyway.
When we process gossip messages asynchronously we may find that we
want to forward a gossip message to a peer after we've returned
from the existing `handle_*` method. In order to do so, we need to
be able to send arbitrary loose gossip messages back to the
`PeerManager` via `MessageSendEvent`.
This commit modifies `MessageSendEvent` in order to support this.
This is purely a refactor that does not change the InitFeatures
advertised by a ChannelManager. This allows users to configure which
features should be advertised based on the values of `UserConfig`. While
there aren't any existing features currently leveraging this behavior,
it will be used by the upcoming anchors_zero_fee_htlc_tx feature.
The UserConfig dependency on provided_init_features caused most
callsites of the main test methods responsible for opening channels to
be updated. This commit foregos that completely by no longer requiring
the InitFeatures of each side to be provided to these methods. The
methods already require a reference to each node's ChannelManager to
open the channel, so we use that same reference to obtain their
InitFeatures. A way to override such features was required for some
tests, so a new `override_init_features` config option now exists on
the test harness.
If, after forwarding an intercepted payment to our counterparty, we
restart with a ChannelMonitor update having been persisted, but the
corresponding ChannelManager update not having been persisted,
we'll still have the intercepted HTLC in the
`pending_intercepted_htlcs` map on start (and potentially a pending
`HTLCIntercepted` event). This will cause us to allow the user to
handle the forwarded HTLC twice, potentially double-forwarding it.
This builds on 0bb87ddad7, which
provided a preemptive fix for the general relay case (though it was
not an actual issue at the time). We simply check for the HTLCs
having been forwarded on startup and remove them from the map.
Fixes#1858
When a channel is force-closed, if a `ChannelMonitor` update is
completed but a `ChannelManager` persist has not yet happened,
HTLCs which were removed in the latest (persisted) `ChannelMonitor`
update will not be failed even though they do not appear in the
commitment transaction which went on chain. This is because the
`ChannelManager` thinks the `ChannelMonitor` is responsible for
them (as it is stale), but the `ChannelMonitor` has no knowledge of
the HTLC at all (as it is not stale).
The fix for this is relatively simple - we need to check for this
specific case and fail back such HTLCs when deserializing a
`ChannelManager`
If, after forwarding a payment to our counterparty, we restart with
a ChannelMonitor update having been persisted, but the
corresponding ChannelManager update was not persisted, we'll still
have the forwarded HTLC in the `forward_htlcs` map on start. This
will cause us to generate a (spurious) `PendingHTLCsForwardable`
event. However, when we go to forward said HTLC, we'll notice the
channel has been closed and leave it up to the `ChannelMontior` to
finalize the HTLC.
This is all fine today - we won't lose any funds, we'll just
generate an excess forwardable event and then fail to forward.
However, in the future when we allow for forward-time channel
changes this could break. Thus, its worth adding tests for this
behavior today, and, while we're at it, removing the spurious
forwardable HTLCs event.
When we process a `channel_reestablish` message we free the HTLC
update holding cell as things may have changed while we were
disconnected. However, some time ago, to handle freeing from the
holding cell when a monitor update completes, we added a holding
cell freeing check in `get_and_clear_pending_msg_events`. This
leaves the in-`channel_reestablish` holding cell clear redundant,
as doing it immediately or is `get_and_clear_pending_msg_events` is
not a user-visible difference.
Thus, we remove the redundant code here, substantially simplifying
`handle_chan_restoration_locked` while we're at it.
