Relay fail messages *after* they are cross-signed #754
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We were previously handling `UpdateFailHtlc` and `UpdateFailMalformedHtlc` similarly to `UpdateFulfillHtlc`, but that is wrong: - a fulfill needs to be propagated as soon as possible, because it allows us to pull funds from upstream - a fail needs to be cross-signed downstream (=irrevocably confirmed) before forwarding it upstream, because it means that we won't be able to pull funds anymore. In other words we need to be absolutely sure that the htlc won't be fulfilled downstream if we fail it upstream, otherwise we risk losing money. Also added tests.
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UpdateFailHtlc/UpdateFailMalformedHtlc *after* there are cross-signed
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UpdateFailHtlc/UpdateFailMalformedHtlc *after* there are cross-signed
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sstone
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Jan 2, 2019
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We were previously handling
UpdateFailHtlcandUpdateFailMalformedHtlcsimilarly toUpdateFulfillHtlc, but that iswrong:
allows us to pull funds from upstream
before forwarding it upstream, because it means that we won't
be able to pull funds anymore. In other words we need to be absolutely
sure that the htlc won't be fulfilled downstream if we fail it upstream,
otherwise we risk losing money.
Also added tests.