after_listpeers() doesn't use the argument, so we don't need to allocate anything.

Signed-off-by: Rusty Russell <[email protected]>

We should not send a message on unknown custom message receipt (we
expect this!).

Signed-off-by: Rusty Russell <[email protected]>

This avoids globals, which is a bit neater.

Signed-off-by: Rusty Russell <[email protected]>

…ing with NULL cb.

This should complete the command, otherwise we get an assertion on
line 1090.

Signed-off-by: Rusty Russell <[email protected]>

By keeping a local hash table, we won't have to look up every time.
We still write to the datastore when it changes, and we need to
initialize it at plugin start.

Signed-off-by: Rusty Russell <[email protected]>

Now actually use our cache.

Signed-off-by: Rusty Russell <[email protected]>

We already get the connected hook, so in there we can add to a hash
table of suitable peers.  Rather than subscribe to disconnection, we
simply remove the peer if a sendcustommsg fails.

This does make after_send_scb_single() a bit more complex, since it
needs this specific node_id: we use a `struct info` per node and a
pointer to a shared "idx" reference counter.

Signed-off-by: Rusty Russell <[email protected]>

This is much better for very large nodes with lots of channel activity.

Signed-off-by: Rusty Russell <[email protected]>

This, too, is vital for large nodes, which don't want a significant
traffic increase.

Signed-off-by: Rusty Russell <[email protected]>

They will in fact get truncated, and never restore.  Large nodes should be using some real
backup strategy!

For this reason, we split "peer_backup" support into send vs store support, so we can
turn off send of our own without disabling storing/sending theirs.

Signed-off-by: Rusty Russell <[email protected]>

…tore users.

When peer backup is enabled by default, it puts things in the datastore, breaking
this assumption.  Narrow the test to examine the specific funder directory.

Signed-off-by: Rusty Russell <[email protected]>

Now we've make it only on existing channels, and not have to call
listdatastore every time, that means we can safely turn it on by
default.

Changelog-Added: Protocol: we now offer peer storage to any peers who create a channel.
Changelog-Deprecated: Config: `--experimental-peer-storage` (it's now the default).
Signed-off-by: Rusty Russell <[email protected]>

We picked one node and iterated.  This means we would only sent to 1,
not 2 nodes if we picked the last (common if there were only a few
peers).  But it also means we would generally send to the same pair of
nodes, which isn't great for redundancy.

Rework to be more random.

Signed-off-by: Rusty Russell <[email protected]>