_ Git - rust-lightning/blob - lightning/src/util/enforcing_trait_impls.rs

   1 use ln::chan_utils::{HTLCOutputInCommitment, TxCreationKeys, ChannelPublicKeys};
   2 use ln::msgs;
   3 use chain::keysinterface::{ChannelKeys, InMemoryChannelKeys};
   4
   5 use std::cmp;
   6 use std::sync::{Mutex, Arc};
   7
   8 use bitcoin::blockdata::transaction::Transaction;
   9
  10 use secp256k1;
  11 use secp256k1::key::{SecretKey, PublicKey};
  12 use secp256k1::{Secp256k1, Signature};
  13 use util::ser::{Writeable, Writer, Readable};
  14 use std::io::Error;
  15 use ln::msgs::DecodeError;
  16
  17 /// Enforces some rules on ChannelKeys calls. Eventually we will probably want to expose a variant
  18 /// of this which would essentially be what you'd want to run on a hardware wallet.
  19 #[derive(Clone)]
  20 pub struct EnforcingChannelKeys {
  21         pub inner: InMemoryChannelKeys,
  22         commitment_number_obscure_and_last: Arc<Mutex<(Option<u64>, u64)>>,
  23 }
  24
  25 impl EnforcingChannelKeys {
  26         pub fn new(inner: InMemoryChannelKeys) -> Self {
  27                 Self {
  28                         inner,
  29                         commitment_number_obscure_and_last: Arc::new(Mutex::new((None, 0))),
  30                 }
  31         }
  32 }
  33
  34 impl EnforcingChannelKeys {
  35         fn check_keys<T: secp256k1::Signing + secp256k1::Verification>(&self, secp_ctx: &Secp256k1<T>,
  36                                                                        keys: &TxCreationKeys) {
  37                 let revocation_base = PublicKey::from_secret_key(secp_ctx, &self.inner.revocation_base_key());
  38                 let payment_base = PublicKey::from_secret_key(secp_ctx, &self.inner.payment_base_key());
  39                 let htlc_base = PublicKey::from_secret_key(secp_ctx, &self.inner.htlc_base_key());
  40
  41                 let remote_points = self.inner.remote_channel_pubkeys.as_ref().unwrap();
  42
  43                 let keys_expected = TxCreationKeys::new(secp_ctx,
  44                                                         &keys.per_commitment_point,
  45                                                         &remote_points.delayed_payment_basepoint,
  46                                                         &remote_points.htlc_basepoint,
  47                                                         &revocation_base,
  48                                                         &payment_base,
  49                                                         &htlc_base).unwrap();
  50                 if keys != &keys_expected { panic!("derived different per-tx keys") }
  51         }
  52 }
  53
  54 impl ChannelKeys for EnforcingChannelKeys {
  55         fn funding_key(&self) -> &SecretKey { self.inner.funding_key() }
  56         fn revocation_base_key(&self) -> &SecretKey { self.inner.revocation_base_key() }
  57         fn payment_base_key(&self) -> &SecretKey { self.inner.payment_base_key() }
  58         fn delayed_payment_base_key(&self) -> &SecretKey { self.inner.delayed_payment_base_key() }
  59         fn htlc_base_key(&self) -> &SecretKey { self.inner.htlc_base_key() }
  60         fn commitment_seed(&self) -> &[u8; 32] { self.inner.commitment_seed() }
  61         fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { self.inner.pubkeys() }
  62
  63         fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
  64                 if commitment_tx.input.len() != 1 { panic!("lightning commitment transactions have a single input"); }
  65                 self.check_keys(secp_ctx, keys);
  66                 let obscured_commitment_transaction_number = (commitment_tx.lock_time & 0xffffff) as u64 | ((commitment_tx.input[0].sequence as u64 & 0xffffff) << 3*8);
  67
  68                 {
  69                         let mut commitment_data = self.commitment_number_obscure_and_last.lock().unwrap();
  70                         if commitment_data.0.is_none() {
  71                                 commitment_data.0 = Some(obscured_commitment_transaction_number ^ commitment_data.1);
  72                         }
  73                         let commitment_number = obscured_commitment_transaction_number ^ commitment_data.0.unwrap();
  74                         assert!(commitment_number == commitment_data.1 || commitment_number == commitment_data.1 + 1);
  75                         commitment_data.1 = cmp::max(commitment_number, commitment_data.1)
  76                 }
  77
  78                 Ok(self.inner.sign_remote_commitment(feerate_per_kw, commitment_tx, keys, htlcs, to_self_delay, secp_ctx).unwrap())
  79         }
  80
  81         fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
  82                 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
  83         }
  84
  85         fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
  86                 self.inner.sign_channel_announcement(msg, secp_ctx)
  87         }
  88
  89         fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
  90                 self.inner.set_remote_channel_pubkeys(channel_pubkeys)
  91         }
  92 }
  93
  94 impl Writeable for EnforcingChannelKeys {
  95         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
  96                 self.inner.write(writer)?;
  97                 let (obscure, last) = *self.commitment_number_obscure_and_last.lock().unwrap();
  98                 obscure.write(writer)?;
  99                 last.write(writer)?;
 100                 Ok(())
 101         }
 102 }
 103
 104 impl<R: ::std::io::Read> Readable<R> for EnforcingChannelKeys {
 105         fn read(reader: &mut R) -> Result<Self, DecodeError> {
 106                 let inner = Readable::read(reader)?;
 107                 let obscure_and_last = Readable::read(reader)?;
 108                 Ok(EnforcingChannelKeys {
 109                         inner: inner,
 110                         commitment_number_obscure_and_last: Arc::new(Mutex::new(obscure_and_last))
 111                 })
 112         }
 113 }