askrene.c was getting quite long, and this is self-contained.
The only code change is a convenience accessor for the per-htlc-cost
hash table.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
"spendable" is for a single HTLC: if we own the channel, this amount
decreases with every HTLC, as we have to pay fees. We have access to this since
we call listpeerchannels anyway, so we can calculate the additional costs and
use it in the refining phase.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We don't actually hit the htlc_max cases, since the flow code already
constrains us to that.
And handling htlc_min is better done in the caller, where diagnostics
are better (basically, we should eliminate them, and if that means no
route, give a clear error message).
And the refinement step can handle any extra millisats from rounding.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is the root cause of the problem worked around in 50949b7b9c
"askrene: hack in some padding so we don't overflow capacities."
When adding fees to flows, we didn't recheck the boundary conditions: in
renepay this is done by routebuilder.
Fortunately, we can use our "reservations" infrastructure to temporarily
use capacity as we process flows, so we handle the cases where they are
not independent correclty.
My assumption is that the resulting errors are small, so we divide
them between the remaining flows based on highest-to-least
probability.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Simply calculate it when we need it, which means we don't have to keep it
up-to-date as we tweak the flow.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We had a workaround for channels added by "auto.local", but instead we
should make it work properly.
I didn't do this before because we can't manipulate the localmods while
they're applied, but it's simple to do it in two stages.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
I used `amount_msat_eq(x, AMOUNT_MSAT(0))` because I forgot this
function existed. I probably missed it because the name is surprising,
so add "is" in there to make it clear it's a boolean function.
You'll note almost all the places which did use it are Eduardo's and
Lisa's code, so maybe it's just me.
Fix up a few places which I could use it, too.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Conversion is lossy, and we don't want to spend more than the channel,
so it's conservative to round down here.
This doesn't actually help our test though!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
You need to know it to make an onion, and in theory if we decided to
fuzz it could be different for different paths.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This populates information on both topology (i.e. unannounced channels) and capacity for the local node using `listpeerchannels`.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This marks all channels around the source node as free (no delay, no fee). This is normally what we want, if we are calculating a path for ourselves.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We don't know anything about most channels, so we create an array of
fp16_t containing them. We zero out ones where we do know something,
and use the previous code as the slow path.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This means we never have to look up a local channel when asked the capacity.
We mark these dummy constraints with an MAX timestamp.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We apply all the gossmods for the layers they specified, and create a
naive routine to give the capacity of a channel given those layers.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
They tell us what paths they're using, so we can adjust capacity estimates
accordingly.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Header from folded patch 'reserve-fixup.patch':
fixup! askrene: reservation implementation.
These are the repositories of all information.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Header from folded patch 'layers-fixup.patch':
fixup! askrene: add layers infrastructure.
