This commit adds a critical capability to the daemon: proper handling
of error cases that occur during the dispatch and forwarding of
multi-hop payments.
The following errors are now properly handled within the daemon:
* unknown payment hash
* unknown destination
* incorrect HTLC amount
* insufficient link capacity
In response to any of these errors, an lnwire.CanceHTLC message will be
back propagated from the spot of the error back to the source of the
payment. In the case of a locally initiated HTLC payment, the error
will be propagated back to the client which initiated the payment.
At this point, proper encrypted error replies as defined within the
spec are not yet implemented and will be fully implemented within a
follow up PR.
This commit fixes an unnoticed bug within the htlcSwitch. Previously
when a peer when offline, the interface+links for that particular peer
were removed from the HTLC switch so we wouldn’t dispatch immediate
HTLC’s in that direction. However, the onion index for that interface
wasn’t also cleared. This would result in a deadlock when a payment
were to be attempted to be forwarded to a peer who recently went
offline.
To fix this issue, we now properly purge the onionIndex of the entry
corresponding to the interface that has gone offline.
This commit makes a large number of minor changes concerning API usage
within the deamon to match the latest version on the upstream btcsuite
libraries.
The major changes are the switch from wire.ShaHash to chainhash.Hash,
and that wire.NewMsgTx() now takes a paramter indicating the version of
the transaction to be created.
This commit adds a much needed feature to the daemon, namely the
ability to force close a channel while the source daemon doesn’t have
an active connection to the counter party. Previously this wasn’t
possible as ALL channel closures were routed through the htlcSwitch
which is only able to trigger a channel closure if the peer is online.
To remedy this, if the closure type is “force” then, we now handle the
channel closure and related RPC streaming updates from the call handler
site of the RPC itself. As a result, there are now only two htlcSwitch
channel closure types: breach, and regular. The logic that’s now in the
rpcSever should likely be refactored into a distinct sub-system, but
getting the initial functionality in is important.
Finally, the channel breach integration test has been modified to skip
connection the peers before attempting the forceful channel closure of
a revoked state as the remote peer no longer needs to be online.
This commit fully integrates the ChannelRouter of the new routing
package into the main lnd daemon.
A number of changes have been made to properly support the new
authenticated gossiping scheme.
Two new messages have been added to the server which allow outside
services to: send a message to all peers possible excluding one, and
send a series of messages to a single peer. These two new capabilities
are used by the ChannelRouter to gossip new accepted announcements and
also to synchronize graph state with a new peer on initial connect.
The switch no longer needs a pointer to the routing state machine as it
no longer needs to report when channels closed since the channel
closures will be detected by the ChannelRouter during graph pruning
when a new block comes in.
Finally, the funding manager now crafts the proper authenticated
announcement to send to the ChannelRouter once a new channel has bene
fully confirmed. As a place holder we have fake signatures everywhere
since we don’t properly store the funding keys and haven’t yet adapted
the Signer interface (or create a new one) that abstracts out the
process of signing a generic interface.
This commit introduces a new sub-system into the daemon whose job it is
to vigilantly watch for any potential channel breaches throughout the
up-time of the daemon. The logic which was moved from the utxoNursery
in a prior commit now resides within the breachArbiter.
Upon start-up the breachArbiter will query the database for all active
channels, launching a goroutine for each channel in order to be able to
take action if a channel breach is detected. The breachArbiter is also
responsible for notifying the htlcSwitch about channel breaches in
order to black-list the breached linked during any multi-hop forwarding
decisions.
Use [33]byte for graph vertex representation.
Delete unneeded stuff:
1. DeepEqual for graph comparison
2. EdgePath
3. 2-thread BFS
4. Table transfer messages and neighborhood radius
5. Beacons
Refactor:
1. Change ID to Vertex
2. Test use table driven approach
3. Add comments
4. Make graph internal representation private
5. Use wire.OutPoint as EdgeId
6. Decouple routing messages from routing implementation
7. Delete Async methods
8. Delete unneeded channels and priority buffer from manager
9. Delete unneeded interfaces in internal graph realisation
10. Renamed ID to Vertex
This commit modifies the existing p2p connection authentication and
encryption scheme to now use the newly designed ‘brontide’
authenticated key agreement scheme for all connections.
Additionally, within the daemon lnwire.NetAddress is now used within
all peers which encapsulates host information, a node’s identity public
key relevant services, and supported bitcoin nets.
This commit slightly modifies the existing CT struct in order to
maintain consistency with code-style. As a result of the name change,
all references have also been renamed from `ct` to `t`.
The Error and Errorf methods have been removed in favor of forcing
everything to be reported via `Fatalf`. Additionally a new method
(ProcessErrors) has been introduced to the networkHarness class in
order to encapsulate the underlying channel.
This commit fixes a bug in the htlcSwitch’s logic to unregister links
after a peer has signaled that a channel has been closed. This bug
would arise when multiple channels were opened with a single peer, and
any of the channels were attempted to be closed. The cause of the bug
was that the slice reference within the map wasn’t previously updated
with the re-slicing to truncate the (duplicated, unneeded) element from
the slice. By updating the map’s reference directly, we fix this
behavior.
The safe handling of adding/removing links/interfaces between the
htlcSwitch’s two goroutines has sprawled a bit, and can be hard to
follow due to the map usage. In the future this section of the code
will be cleaned up and the redundant indexes removed.
This commit properly removes any/all closed channels from the routing
table. In the current implementation individual links (channels)
between nodes are treated sparely from the PoV of the routing table. In
the future, this behavior should be modified such that, the routing
table views all the links between nodes as a single channel. Such a
change will simplify the task of path finding as the links can simply
be viewed as a channel with the sum of their capacities. The link layer
(htlcSwitch) will handle the details of fragmentation on a local basis.
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 includes some slight refactoring to properly execute force
closures which are initiated by RPC clients.
The CloseLink method within the htlcSwitch has been extended to take an
additional parameter which indicates if the link should be closed
forcefully. If so, then the channelManager which dispatches the request
executes a force closure using the target channel state machine. Once
the closing transaction has been broadcast, the summary is sent to the
utxoNursery so the outputs can be swept once they’re mature.
This commit modifies the internal workflow for opening or closing a
channel in order to create a path in which RPC clients can receive
updates. Updates are now communicated via channels from the goroutines
spawned by the RPC server to process the request, and the sub-system
within the daemon that actually executes the request.
With this change clients can now receive updates that the request is
pending (final message has been sent to the target client), or that the
request has been completed. Confirmation related updates have not yet
been implemented as that will require some changes to the ChainNotifier
interface.
This commit fixes an omission within the htlcSwitch. With this commit,
a channels bandwidth is now properly updated once an incoming HTLC is
settled.
This also fixes a bug where if a node received a payment, it wouldn’t
be able to then utilize the newly available bandwidth to send further
payments.
This commit adds a basic test for cooperative channel closure. The
current test ensures correctness of the cooperative closure procedure
initiated by either the channel initiator, or the channel responder.
This commit fixes a concurrency bug between the server’s htlc switch,
and an instance of a peer’s active htlc manager goroutine.
The deadlock condition was triggered when the htlc manager’s downstream
`htlcPacket` channel was full, causing the htlcSwitch’s main loop to
block on a send while the htlcManager was attempting to send a packet
to the switch for forwarding. This scenario created a circular
dependency resting in a deadlock.
The fix for this bug is relatively straight forward, if the destination
interface is found when handling an outgoing payment, then a new
goroutine is spawned to complete the request.
This commit adds a ticker which attempts to print the total volume
sent/recv over the last 10 seconds if any updates took place during
that interval.
Additionally, when selecting a link to forward an htlcPacket insert a
break after selection in order to properly terminate the loop.
With this commit, calls to htlcSwitch.SendHTLC() are now synchronous,
only returning after the payment has been fully settled. This will
allow one to accurately measure the commitment update speed with the
current state machine implementation which is missing a number of
low-hanging optimizations.
The htlcManager for each channel now keeps a map of cleared HTLC’s
keyed by the index number of the add entry within the state machine’s
HTLC log. This map of HTLC’s will later be used to properly implement
time outs
Additionally, a slight refactoring has been executed w.r.t handling
upstream/downstream messages. This cleans up the main htlcManager loop,
freeing it up for the addition of future logic to properly observe
timeouts as well as, proper batching+trickling of HTLC updates, and a
commitment signature ticker.
This commit introduces the HtlcSwitch service into the daemon. The
purpose of the switch is to manage the message passing between the
goutiness within he peer managing each active channel. The switch
treats connected peers as interfaces, and their active channels as
links. All multi-hop, single-hop, and channel closure orchestration
will be managed by various goroutines within the HtlcSwitch.
The HtlcSwitch will also serve as the L2 contact point between the
yet-to-be-written LightningRouter and the switch, forwarding the new
htlc packet on the proper interface. Additionally, the switch will
handle dispatching htlc’s created locally via RPC, and multi-hop
forwarding initiated by peers.
This commit adds the necessary plumbing within the server, peer, and
rpcServer to handle opening and cooperatively closing a channel with a
remote peer.
Many new data structures have been added to the peer in order to allow
it to efficiently manage opening+.losing new/existing lightning
channels. Additional documentation has been added to several methods
within the peer struct, with some minor renaming along with way. The
peer has also gained a dedicated goroutine whose job it is to manage
any requests pertaining to opening, or closing any channels with the
remote peer.
The messages have been added to lnrpc define the requests and responses
to channel open+close messages. Additional channel logic has been added
between the rpcServer, peer, and server in order to properly manage the
necessary synchronization.
