This commit adds the ability for clients within the daemon to register
for notifications that are dispatched once invoices are settled, or new
invoices are added. Such notifications can prove useful when
synchronizing higher level primitives, or implementing workflow within
desktop/mobile UI’s.
This commit adds full support for multi-hop onion routed payments
within the daemon.
The switch has been greatly extended in order to gain the functionality
required to manage Sphinx payment circuits amongst active links. A
payment circuit is initiated when a link sends an HTLC add to the
downstream htlcSwitch it received from the upstream peer. The switch
then examines the parsed sphinx packet to set up the clear/settle ends
of the circuit. Created circuits can be re-used amongst HTLC payments
which share the same RHash.
All bandwidth updates within a link’s internal state are now managed
with atomic increments/decrements in order to avoid race conditions
amongst the two goroutines the switch currently uses.
Each channel’s htlcManager has also been extended to parse out the
next-hop contained within Sphinx packets, and construct a proper
htlcPkt such that the htlcSwitch can initiate then manage the payment
circuit.
This commit extends the existing invoiceRegistry functionality to wrap
the on-disk invoices available via the channeldb with an in-memory
cache on invoices. Currently the in-memory cache is only reserved for
the storage of special “debug” invoices which all nodes are able to
settle immediately.
This commit introduces the invoice registry which is a central
repository of all outstanding invoices related to the daemon.
This registry will be used by the goroutines which manage the htlc’s
for a particular channel, and later by the point-to-point workflow
which negotiates the conditions for payment along with signed recipes.
