This is prep work for when we sign htlc txs with
SIGHASH_SINGLE|SIGHASH_ANYONECANPAY.
We still deal with raw signatures for the htlc txs at the moment, since
we send them like that across the wire, and changing that was simply too
painful (for the moment?).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
tal_count() is used where there's a type, even if it's char or u8, and
tal_bytelen() is going to replace tal_len() for clarity: it's only needed
where a pointer is void.
We shim tal_bytelen() for now.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
For non-delayed HTLC success spends, we have a similar pattern ("<sig>
<preimage> <wscript>") so a we want to use the same function.
The other routines don't say "witness" in them, and should.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
So far we always needed to know the public key, which was not the case
for addresses that we don't own. Moving the hashing outside of the
script construction allows us to send to arbitrary addresses. I also
added the hash computation to the pubkey primitives.
aka "BOLT 3: Use revocation key hash rather than revocation key",
which builds on top of lightningnetwork/lightning-rfc#105 "BOLT 2,3,5:
Make htlc outputs of the commitment tx spendable with revocation key".
This affects callers, since they now need to hand us the revocation
pubkey, but commit_tx has that already anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is a bit tricky: for our signing code, we don't want scriptsigs,
but to calculate the txid, we need them. For most transactions in lightning,
they're pure segwit so it doesn't matter, but funding transactions can
have P2SH-wrapped P2WPKH inputs.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is a step away from the previous more generic script types into
specific helpers for each transaction type we need.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
And use this to resolve old transactions by comparing outputs with
HTLCs.
Rather than remembering the output ordering for every one of their
previous commitment transactions, we just remember the commitment
number for each commitment txid, and when we see it, derive all the
HTLC scriptpubkeys and the to-us and to-them scriptpubkeys, and figure
out which is which.
This avoids us having to save information on disk, except for the
txid->commitment-number mapping (and the shachain).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We use libsecp256k1 to convert signatures to DER; we were creating a
temporary one, but we really should be handing the one we have in dstate
through. This does that, everywhere.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We now need to use bitcoin_witness_htlc with the r value, so that API
is updated to take 'struct rval' or 'struct sha256'.
We use the nc->delay amount (ie. dstate->config.min_htlc_expiry) to
wait for a timeout refund to be buried before "failing" upstream.
This should probably be made into a clearer parameter rather than
overloading this one.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Header from folded patch 'dont-use-peer-nc-in-onchain-code.patch':
peer: Don't use peer->nc->delay for onchain case.
Use the config var directly. We should be freeing peer->nc when the
connection dies anyway.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We need to enforce this onchain as we do in the protocol off-chain,
otherwise we can have an onchain redemption we can't redeem upstream
via the protocol. While Laolu points out there's a 520 byte limit on
witness stack element, that can still make for a larger tx and make
problems for the steal tx case.
The downside is that even the timeout transaction, which used to spend
the HTLC with an empty 'secret', now needs a 32-byte secret, making it
a little larger. We create a 'bitcoin_witness_htlc' helper for this
case.
See: http://lists.linuxfoundation.org/pipermail/lightning-dev/2016-May/000529.html
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
They could be scriptpubkeys, but they're actually used inside p2wsh,
so they're really witness scripts. We use the term "redeem" elsewhere
from when we were using p2sh, though.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We want this because P2SH is something we can tell bitcoind to pay to;
we can't (yet?) do that with "raw" P2WPKH.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
sign_tx_input() now takes a witness_script arg: P2WPKH doesn't really
have a witness_script, but for signing it behaves as if it does.
This helper constructs that "fake" witness_script.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
I got confused navigating these, especially since Alpha and Bitcoin
have diverged (BIP68 was proposed after Elements Alpha).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
As documented in the paper; it's also two bytes shorter, and allows
us to use the exact same script for three cases.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty Russell
lisa neigut
practicalswift
Christian Decker