ad522a72c1
In this commit, we extend the switch as is, to record details concerning settled payment circuits. To do this, we introduce a new interface to the package: the ForwardingLog. This is a tiny interface that simply lets us abstract away the details of the storage backing of the forwarding log. Each time we receive a successful HTLC settle, we’ll log the full details (chans, fees, time) as a pending forwarding log entry. Every 15 seconds, we’ll then batch flush out these entries to disk. When we’re exiting, we’ll try to flush out all entries to ensure everything gets recorded to disk.
136 lines
5.1 KiB
Go
136 lines
5.1 KiB
Go
package htlcswitch
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import (
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"github.com/lightningnetwork/lnd/channeldb"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/roasbeef/btcd/chaincfg/chainhash"
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"github.com/roasbeef/btcd/wire"
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)
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// InvoiceDatabase is an interface which represents the persistent subsystem
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// which may search, lookup and settle invoices.
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type InvoiceDatabase interface {
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// LookupInvoice attempts to look up an invoice according to its 32
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// byte payment hash.
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LookupInvoice(chainhash.Hash) (channeldb.Invoice, error)
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// SettleInvoice attempts to mark an invoice corresponding to the
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// passed payment hash as fully settled.
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SettleInvoice(chainhash.Hash) error
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}
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// ChannelLink is an interface which represents the subsystem for managing the
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// incoming htlc requests, applying the changes to the channel, and also
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// propagating/forwarding it to htlc switch.
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//
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// abstraction level
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// ^
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// |
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// | - - - - - - - - - - - - Lightning - - - - - - - - - - - - -
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// |
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// | (Switch) (Switch) (Switch)
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// | Alice <-- channel link --> Bob <-- channel link --> Carol
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// |
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// | - - - - - - - - - - - - - TCP - - - - - - - - - - - - - - -
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// |
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// | (Peer) (Peer) (Peer)
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// | Alice <----- tcp conn --> Bob <---- tcp conn -----> Carol
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// |
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//
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type ChannelLink interface {
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// TODO(roasbeef): modify interface to embed mail boxes?
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// HandleSwitchPacket handles the switch packets. This packets might be
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// forwarded to us from another channel link in case the htlc update
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// came from another peer or if the update was created by user
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// initially.
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//
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// NOTE: This function MUST be non-blocking (or block as little as
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// possible).
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HandleSwitchPacket(*htlcPacket)
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// HandleChannelUpdate handles the htlc requests as settle/add/fail
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// which sent to us from remote peer we have a channel with.
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//
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// NOTE: This function MUST be non-blocking (or block as little as
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// possible).
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HandleChannelUpdate(lnwire.Message)
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// ChanID returns the channel ID for the channel link. The channel ID
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// is a more compact representation of a channel's full outpoint.
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ChanID() lnwire.ChannelID
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// ShortChanID returns the short channel ID for the channel link. The
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// short channel ID encodes the exact location in the main chain that
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// the original funding output can be found.
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ShortChanID() lnwire.ShortChannelID
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// UpdateShortChanID updates the short channel ID for a link. This may
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// be required in the event that a link is created before the short
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// chan ID for it is known, or a re-org occurs, and the funding
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// transaction changes location within the chain.
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UpdateShortChanID(lnwire.ShortChannelID)
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// UpdateForwardingPolicy updates the forwarding policy for the target
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// ChannelLink. Once updated, the link will use the new forwarding
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// policy to govern if it an incoming HTLC should be forwarded or not.
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UpdateForwardingPolicy(ForwardingPolicy)
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// Bandwidth returns the amount of milli-satoshis which current link
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// might pass through channel link. The value returned from this method
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// represents the up to date available flow through the channel. This
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// takes into account any forwarded but un-cleared HTLC's, and any
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// HTLC's which have been set to the over flow queue.
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Bandwidth() lnwire.MilliSatoshi
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// Stats return the statistics of channel link. Number of updates,
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// total sent/received milli-satoshis.
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Stats() (uint64, lnwire.MilliSatoshi, lnwire.MilliSatoshi)
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// Peer returns the representation of remote peer with which we have
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// the channel link opened.
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Peer() Peer
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// EligibleToForward returns a bool indicating if the channel is able
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// to actively accept requests to forward HTLC's. A channel may be
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// active, but not able to forward HTLC's if it hasn't yet finalized
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// the pre-channel operation protocol with the remote peer. The switch
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// will use this function in forwarding decisions accordingly.
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EligibleToForward() bool
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// Start/Stop are used to initiate the start/stop of the channel link
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// functioning.
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Start() error
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Stop()
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}
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// Peer is an interface which represents the remote lightning node inside our
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// system.
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type Peer interface {
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// SendMessage sends message to remote peer.
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SendMessage(lnwire.Message) error
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// WipeChannel removes the channel uniquely identified by its channel
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// point from all indexes associated with the peer.
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WipeChannel(*wire.OutPoint) error
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// PubKey returns the serialize public key of the source peer.
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PubKey() [33]byte
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// Disconnect disconnects with peer if we have error which we can't
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// properly handle.
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Disconnect(reason error)
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}
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// ForwardingLog is an interface that represents a time series database which
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// keep track of all successfully completed payment circuits. Every few
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// seconds, the switch will collate and flush out all the successful payment
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// circuits during the last interval.
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type ForwardingLog interface {
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// AddForwardingEvents is a method that should write out the set of
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// forwarding events in a batch to persistent storage. Outside
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// sub-systems can then query the contents of the log for analysis,
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// visualizations, etc.
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AddForwardingEvents([]channeldb.ForwardingEvent) error
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}
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