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lnwallet: fix bug with funding channels with 50/50 balances

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This commit fixes a prior bug in the wallet triggered by the creation
of a channel using the single funder workflow, but pushing exactly
*half* of the channel over to the other side. The prior logic to
determine who the initiator would result in a disagreement over who
created the channel initially. This wouldn’t manifest until the channel
was attempted to be closed cooperatively. As both side disagreed about
who created the channel they would apply the closing fee to different
outputs, thereby creating mismatched closing transaction. The signature
would fail to validate as the closer will create a different
transaction from that of the responder.

This commit fixes the issue by properly detecting who initially created
the channel.
This commit is contained in:
Olaoluwa Osuntokun 2017-01-16 20:28:30 -08:00
parent f82d957c90
commit e60f40b845
No known key found for this signature in database
GPG Key ID: 9CC5B105D03521A2
1 changed files with 13 additions and 24 deletions
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37
lnwallet/reservation.go
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@ -146,6 +146,7 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount, minFeeRate btcut
var (
ourBalance btcutil.Amount
theirBalance btcutil.Amount
initiator bool
)
// If we're the responder to a single-funder reservation, then we have
@ -154,6 +155,7 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount, minFeeRate btcut
if fundingAmt == 0 {
ourBalance = pushSat
theirBalance = capacity - commitFee - pushSat
initiator = false
} else {
// TODO(roasbeef): need to rework fee structure in general and
// also when we "unlock" dual funder within the daemon
@ -172,34 +174,21 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount, minFeeRate btcut
}
theirBalance = capacity - fundingAmt - commitFee + pushSat
initiator = true
}
var (
initiator bool
chanType channeldb.ChannelType
)
switch {
// If our balance is zero, or we're being pushed our entire balance in
// the first state, then we're the responder to a single funder
// channel workflow.
case pushSat != 0 && ourBalance-pushSat == 0:
fallthrough
case ourBalance == 0:
initiator = false
chanType = channeldb.SingleFunder
// Next we'll set the channel type based on what we can ascertain about
// the balances/push amount within the channel.
var chanType channeldb.ChannelType
// If their balance is zero, or being pushed entirely to them, then
// we're the initiator to a single funder channel workflow.
case pushSat != 0 && theirBalance-pushSat == 0:
fallthrough
case theirBalance == 0:
initiator = true
// If either of the balances are zero at this point, or we have a
// non-zero push amt (there's no pushing for dual funder), then this is
// a single-funder channel.
if ourBalance == 0 || theirBalance == 0 || pushSat != 0 {
chanType = channeldb.SingleFunder
// Otherwise, if both sides are starting out with a non-zero balance,
// then neither of us is technically the "initiator" and this is a dual
// funder channel.
default:
} else {
// Otherwise, this is a dual funder channel, and no side is
// technically the "initiator"
initiator = false
chanType = channeldb.DualFunder
}