mirrors/lightning-bolts
1
0
Fork 0
mirror of https://github.com/lightning/bolts.git synced 2025-01-19 05:33:37 +01:00
Code Issues Projects Releases Wiki Activity

BOLT 4: don't allow a "fee" for the final node.

Browse Source 
I recently made a cut & paste bug with the protocol tests, and
paid an HTLC of amount 100M msat, but with only a 1M msat `amt_to_forward`
in the hop_data.  To my surprise, it was accepted.

This is because we allow overpaying the routing fee (considered 0
for the final hop).  This doesn't make sense for the final hop: anything
but exact equality implies a bug, or that the previous node took the
wrong amount from the payment.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2019-12-03 14:19:40 +10:30
parent 0fb66ca6cc
commit 2422630274
1 changed files with 6 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
04-onion-routing.md
View File

@ -198,7 +198,7 @@ Field descriptions:
* `amt_to_forward`: The amount, in millisatoshis, to forward to the next * `amt_to_forward`: The amount, in millisatoshis, to forward to the next
receiving peer specified within the routing information. receiving peer specified within the routing information.
This value amount MUST include the origin node's computed _fee_ for the For non-final nodes, this value amount MUST include the origin node's computed _fee_ for the
receiving peer. When processing an incoming Sphinx packet and the HTLC receiving peer. When processing an incoming Sphinx packet and the HTLC
message that it is encapsulated within, if the following inequality doesn't hold, message that it is encapsulated within, if the following inequality doesn't hold,
then the HTLC should be rejected as it would indicate that a prior hop has then the HTLC should be rejected as it would indicate that a prior hop has
@ -206,9 +206,11 @@ Field descriptions:
incoming_htlc_amt - fee >= amt_to_forward incoming_htlc_amt - fee >= amt_to_forward
Where `fee` is either calculated according to the receiving peer's advertised fee Where `fee` is calculated according to the receiving peer's advertised fee
schema (as described in [BOLT #7](07-routing-gossip.md#htlc-fees)) schema (as described in [BOLT #7](07-routing-gossip.md#htlc-fees).
or is 0, if the processing node is the final node.
For the final node, this value MUST be exactly equal to the incoming htlc
amount, otherwise the HTLC should be rejected.
* `outgoing_cltv_value`: The CLTV value that the _outgoing_ HTLC carrying * `outgoing_cltv_value`: The CLTV value that the _outgoing_ HTLC carrying
the packet should have. the packet should have.