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discovery: refactor re-processing rejected announcements into new method

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This commit is contained in:
Olaoluwa Osuntokun 2017-12-26 16:28:17 +01:00
parent 68dabe3594
commit 38715ca768
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GPG Key ID: 964EA263DD637C21
1 changed files with 97 additions and 69 deletions
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166
discovery/gossiper.go
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@ -1092,6 +1092,83 @@ func (d *AuthenticatedGossiper) processFeeChanUpdate(feeUpdate *feeUpdateRequest
return chanUpdates, nil
}
// processRejectedEdge examines a rejected edge to see if we can eexrtact any
// new announcements from it. An edge will get rejected if we already added
// the same edge without AuthProof to the graph. If the received announcement
// contains a proof, we can add this proof to our edge. We can end up in this
// situatation in the case where we create a channel, but for some reason fail
// to receive the remote peer's proof, while the remote peer is able to fully
// assemble the proof and craft the ChannelAnnouncement.
func (d *AuthenticatedGossiper) processRejectedEdge(chanAnnMsg *lnwire.ChannelAnnouncement,
proof *channeldb.ChannelAuthProof) ([]networkMsg, error) {
// First, we'll fetch the state of the channel as we know if from the
// database.
chanInfo, e1, e2, err := d.cfg.Router.GetChannelByID(
chanAnnMsg.ShortChannelID,
)
if err != nil {
return nil, err
}
// The edge is in the graph, and has a proof attached, then we'll just
// reject it as normal.
if chanInfo.AuthProof != nil {
return nil, nil
}
// Otherwise, this means that the edge is within the graph, but it
// doesn't yet have a proper proof attached.
// We'll then create then validate the new fully assembled
// announcement.
chanAnn, e1Ann, e2Ann := createChanAnnouncement(
proof, chanInfo, e1, e2,
)
err = ValidateChannelAnn(chanAnn)
if err != nil {
err := errors.Errorf("assembled channel announcement proof "+
"for shortChanID=%v isn't valid: %v",
chanAnnMsg.ShortChannelID, err)
log.Error(err)
return nil, err
}
// If everything checks out, then we'll add the fully assembled proof
// to the database.
err = d.cfg.Router.AddProof(chanAnnMsg.ShortChannelID, proof)
if err != nil {
err := errors.Errorf("unable add proof to shortChanID=%v: %v",
chanAnnMsg.ShortChannelID, err)
log.Error(err)
return nil, err
}
// As we now have a complete channel announcement for this channel,
// we'll construct the announcement so they can be broadcast out to all
// our peers.
announcements := make([]networkMsg, 0, 3)
announcements = append(announcements, networkMsg{
msg: chanAnn,
peer: d.selfKey,
})
if e1Ann != nil {
announcements = append(announcements, networkMsg{
msg: e1Ann,
peer: d.selfKey,
})
}
if e2Ann != nil {
announcements = append(announcements, networkMsg{
msg: e2Ann,
peer: d.selfKey,
})
}
return announcements, nil
}
// processNetworkAnnouncement processes a new network relate authenticated
// channel or node announcement or announcements proofs. If the announcement
// didn't affect the internal state due to either being out of date, invalid,
@ -1105,7 +1182,7 @@ func (d *AuthenticatedGossiper) processNetworkAnnouncement(nMsg *networkMsg) []n
return chanID.BlockHeight+delta > bestHeight
}
var announcements []lnwire.Message
var announcements []networkMsg
switch msg := nMsg.msg.(type) {
@ -1243,84 +1320,35 @@ func (d *AuthenticatedGossiper) processNetworkAnnouncement(nMsg *networkMsg) []n
// partial node will be added to represent each node while we
// wait for a node announcement.
if err := d.cfg.Router.AddEdge(edge); err != nil {
// If the edge was rejected due to already being known,
// then it may be that case that this new message has a
// fresh channel proof, so we'll cechk.
if routing.IsError(err, routing.ErrOutdated,
routing.ErrIgnored) {
// The edge will get rejected if we already
// added the same edge without AuthProof to the
// graph. If the received announcement contains
// a proof, we can add this proof to our edge.
// We can end up in this situatation in the case
// where we create a channel, but for some
// reason fail to receive the remote peer's
// proof, while the remote peer is able to fully
// assemble the proof and craft the
// ChannelAnnouncement.
// TODO(halseth): the following chunk of code
// should be moved into own method, indentation
// and readability is not exactly on point.
chanInfo, e1, e2, err2 := d.cfg.Router.GetChannelByID(
msg.ShortChannelID)
if err2 != nil {
log.Errorf("Failed fetching channel "+
"edge: %v", err2)
nMsg.err <- err2
// Attempt to process the rejected message to
// see if we get any new announcements.
anns, rErr := d.processRejectedEdge(msg, proof)
if err != nil {
nMsg.err <- rErr
return nil
}
// If the edge already exists in the graph, but
// has no proof attached, we can add that now.
if chanInfo.AuthProof == nil && proof != nil {
chanAnn, e1Ann, e2Ann :=
createChanAnnouncement(proof,
chanInfo, e1, e2)
// Validate the assembled proof.
err := ValidateChannelAnn(chanAnn)
if err != nil {
err := errors.Errorf("assembled"+
"channel announcement "+
"proof for shortChanID=%v"+
" isn't valid: %v",
msg.ShortChannelID, err)
log.Error(err)
nMsg.err <- err
return nil
}
err = d.cfg.Router.AddProof(
msg.ShortChannelID, proof)
if err != nil {
err := errors.Errorf("unable "+
"add proof to "+
"shortChanID=%v: %v",
msg.ShortChannelID, err)
log.Error(err)
nMsg.err <- err
return nil
}
announcements = append(announcements,
chanAnn)
if e1Ann != nil {
announcements = append(
announcements, e1Ann)
}
if e2Ann != nil {
announcements = append(
announcements, e2Ann)
}
// If while processing this rejected edge, we
// realized there's a set of announcements we
// could extract, then we'll return those
// directly.
if len(anns) != 0 {
nMsg.err <- nil
return announcements
return anns
}
// If not, this was just an outdated edge.
log.Debugf("Router rejected channel edge: %v",
err)
// Otherwise, this is just a regular rejected edge.
log.Debugf("Router rejected channel "+
"edge: %v", err)
} else {
log.Errorf("Router rejected channel edge: %v",
err)
log.Errorf("Router rejected channel "+
"edge: %v", err)
}
nMsg.err <- err