X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;ds=sidebyside;f=lightning%2Fsrc%2Fln%2Fchannel.rs;h=d754b393c389bc441089310c49856005d78066be;hb=9be497cad4b89ddaf5919f99e2ea5ac9a8ab8bd0;hp=0c30a7e96cb53bfec845174a2417e002aedce211;hpb=d77e40fa76d7f6f9ab5c5ae91d686ac8b8226b3f;p=rust-lightning diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index 0c30a7e9..d754b393 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -53,19 +53,43 @@ enum InboundHTLCRemovalReason { } enum InboundHTLCState { - /// Added by remote, to be included in next local commitment tx. + /// Offered by remote, to be included in next local commitment tx. I.e., the remote sent an + /// update_add_htlc message for this HTLC. RemoteAnnounced(PendingHTLCStatus), - /// Included in a received commitment_signed message (implying we've revoke_and_ack'ed it), but - /// the remote side hasn't yet revoked their previous state, which we need them to do before we - /// accept this HTLC. Implies AwaitingRemoteRevoke. - /// We also have not yet included this HTLC in a commitment_signed message, and are waiting on - /// a remote revoke_and_ack on a previous state before we can do so. + /// Included in a received commitment_signed message (implying we've + /// revoke_and_ack'd it), but the remote hasn't yet revoked their previous + /// state (see the example below). We have not yet included this HTLC in a + /// commitment_signed message because we are waiting on the remote's + /// aforementioned state revocation. One reason this missing remote RAA + /// (revoke_and_ack) blocks us from constructing a commitment_signed message + /// is because every time we create a new "state", i.e. every time we sign a + /// new commitment tx (see [BOLT #2]), we need a new per_commitment_point, + /// which are provided one-at-a-time in each RAA. E.g., the last RAA they + /// sent provided the per_commitment_point for our current commitment tx. + /// The other reason we should not send a commitment_signed without their RAA + /// is because their RAA serves to ACK our previous commitment_signed. + /// + /// Here's an example of how an HTLC could come to be in this state: + /// remote --> update_add_htlc(prev_htlc) --> local + /// remote --> commitment_signed(prev_htlc) --> local + /// remote <-- revoke_and_ack <-- local + /// remote <-- commitment_signed(prev_htlc) <-- local + /// [note that here, the remote does not respond with a RAA] + /// remote --> update_add_htlc(this_htlc) --> local + /// remote --> commitment_signed(prev_htlc, this_htlc) --> local + /// Now `this_htlc` will be assigned this state. It's unable to be officially + /// accepted, i.e. included in a commitment_signed, because we're missing the + /// RAA that provides our next per_commitment_point. The per_commitment_point + /// is used to derive commitment keys, which are used to construct the + /// signatures in a commitment_signed message. + /// Implies AwaitingRemoteRevoke. + /// [BOLT #2]: https://github.com/lightningnetwork/lightning-rfc/blob/master/02-peer-protocol.md AwaitingRemoteRevokeToAnnounce(PendingHTLCStatus), - /// Included in a received commitment_signed message (implying we've revoke_and_ack'ed it), but - /// the remote side hasn't yet revoked their previous state, which we need them to do before we - /// accept this HTLC. Implies AwaitingRemoteRevoke. - /// We have included this HTLC in our latest commitment_signed and are now just waiting on a - /// revoke_and_ack. + /// Included in a received commitment_signed message (implying we've revoke_and_ack'd it). + /// We have also included this HTLC in our latest commitment_signed and are now just waiting + /// on the remote's revoke_and_ack to make this HTLC an irrevocable part of the state of the + /// channel (before it can then get forwarded and/or removed). + /// Implies AwaitingRemoteRevoke. AwaitingAnnouncedRemoteRevoke(PendingHTLCStatus), Committed, /// Removed by us and a new commitment_signed was sent (if we were AwaitingRemoteRevoke when we @@ -1095,10 +1119,10 @@ impl Channel { fn build_local_transaction_keys(&self, commitment_number: u64) -> Result { let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &self.build_local_commitment_secret(commitment_number)); let delayed_payment_base = &self.local_keys.pubkeys().delayed_payment_basepoint; - let htlc_basepoint = PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key()); + let htlc_basepoint = &self.local_keys.pubkeys().htlc_basepoint; let their_pubkeys = self.their_pubkeys.as_ref().unwrap(); - Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, &htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint), "Local tx keys generation got bogus keys")) + Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint), "Local tx keys generation got bogus keys")) } #[inline] @@ -1109,10 +1133,10 @@ impl Channel { //TODO: Ensure that the payment_key derived here ends up in the library users' wallet as we //may see payments to it! let revocation_basepoint = &self.local_keys.pubkeys().revocation_basepoint; - let htlc_basepoint = PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key()); + let htlc_basepoint = &self.local_keys.pubkeys().htlc_basepoint; let their_pubkeys = self.their_pubkeys.as_ref().unwrap(); - Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &self.their_cur_commitment_point.unwrap(), &their_pubkeys.delayed_payment_basepoint, &their_pubkeys.htlc_basepoint, revocation_basepoint, &htlc_basepoint), "Remote tx keys generation got bogus keys")) + Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &self.their_cur_commitment_point.unwrap(), &their_pubkeys.delayed_payment_basepoint, &their_pubkeys.htlc_basepoint, revocation_basepoint, htlc_basepoint), "Remote tx keys generation got bogus keys")) } /// Gets the redeemscript for the funding transaction output (ie the funding transaction output @@ -3318,7 +3342,7 @@ impl Channel { revocation_basepoint: local_keys.revocation_basepoint, payment_point: local_keys.payment_point, delayed_payment_basepoint: local_keys.delayed_payment_basepoint, - htlc_basepoint: PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key()), + htlc_basepoint: local_keys.htlc_basepoint, first_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &local_commitment_secret), channel_flags: if self.config.announced_channel {1} else {0}, shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() }) @@ -3352,7 +3376,7 @@ impl Channel { revocation_basepoint: local_keys.revocation_basepoint, payment_point: local_keys.payment_point, delayed_payment_basepoint: local_keys.delayed_payment_basepoint, - htlc_basepoint: PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key()), + htlc_basepoint: local_keys.htlc_basepoint, first_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &local_commitment_secret), shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() }) } @@ -4479,8 +4503,8 @@ mod tests { let delayed_payment_base = &chan.local_keys.pubkeys().delayed_payment_basepoint; let per_commitment_secret = SecretKey::from_slice(&hex::decode("1f1e1d1c1b1a191817161514131211100f0e0d0c0b0a09080706050403020100").unwrap()[..]).unwrap(); let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret); - let htlc_basepoint = PublicKey::from_secret_key(&secp_ctx, chan.local_keys.htlc_base_key()); - let keys = TxCreationKeys::new(&secp_ctx, &per_commitment_point, delayed_payment_base, &htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint).unwrap(); + let htlc_basepoint = &chan.local_keys.pubkeys().htlc_basepoint; + let keys = TxCreationKeys::new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint).unwrap(); chan.their_pubkeys = Some(their_pubkeys);