lnbase: fix tx amounts

lib/lnbase.py

@@ -252,8 +252,13 @@ def get_obscured_ctn(ctn, local, remote):
     mask = int.from_bytes(H256(local + remote)[-6:], byteorder="big")
     return ctn ^ mask
 
+def overall_weight(num_htlc):
+    return 500 + 172 * num_htlc + 224
 
-def make_commitment(local_pubkey, remote_pubkey, payment_pubkey, remote_payment_pubkey, revocation_pubkey, delayed_pubkey, funding_txid, funding_pos, funding_satoshis):
+def make_commitment(local_pubkey, remote_pubkey,
+                    payment_pubkey, remote_payment_pubkey, revocation_pubkey, delayed_pubkey,
+                    funding_txid, funding_pos, funding_satoshis,
+                    to_local_msat, to_remote_msat, local_feerate):
     pubkeys = sorted([bh2u(local_pubkey), bh2u(remote_pubkey)])
     obs = get_obscured_ctn(0, payment_pubkey, remote_payment_pubkey)
     locktime = (0x20 << 24) + (obs & 0xffffff)
@@ -274,9 +279,10 @@ def make_commitment(local_pubkey, remote_pubkey, payment_pubkey, remote_payment_
     # commitment tx outputs
     local_script = bytes([opcodes.OP_IF]) + revocation_pubkey + bytes([opcodes.OP_ELSE, opcodes.OP_CSV, opcodes.OP_DROP]) + delayed_pubkey + bytes([opcodes.OP_ENDIF, opcodes.OP_CHECKSIG])
     local_address = bitcoin.redeem_script_to_address('p2wsh', bh2u(local_script))
-    local_amount = funding_satoshis
+    fee = local_feerate * overall_weight(0) // 1000
+    local_amount = to_local_msat // 1000 - fee
     remote_address = bitcoin.pubkey_to_address('p2wpkh', bh2u(remote_pubkey))
-    remote_amount = 0
+    remote_amount = to_remote_msat // 1000
     to_local = (bitcoin.TYPE_ADDRESS, local_address, local_amount)
     to_remote = (bitcoin.TYPE_ADDRESS, remote_address, remote_amount)
     # no htlc for the moment
@@ -459,9 +465,12 @@ class Peer(PrintError):
         funding_tx = wallet.mktx([funding_output], None, config, 1000)
         funding_index = funding_tx.outputs().index(funding_output)
         remote_payment_pubkey = accept_channel['payment_basepoint']
-        c_tx = make_commitment(funding_pubkey, remote_pubkey, payment_pubkey, remote_payment_pubkey, revocation_pubkey, delayed_pubkey, funding_tx.txid(), funding_index, funding_satoshis)
+        c_tx = make_commitment(
+            funding_pubkey, remote_pubkey,
+            payment_pubkey, remote_payment_pubkey, revocation_pubkey, delayed_pubkey,
+            funding_tx.txid(), funding_index, funding_satoshis,
+            funding_satoshis*1000, 0, 20000)
         c_tx.sign({bh2u(funding_pubkey): (funding_privkey, True)})
-
         sig_index = pubkeys.index(bh2u(funding_pubkey))
         sig = bytes.fromhex(c_tx.inputs()[0]["signatures"][sig_index])
         self.print_error('sig', len(sig))

lib/tests/test_lnbase.py

@@ -42,7 +42,8 @@ class Test_LNBase(unittest.TestCase):
             local_funding_pubkey, remote_funding_pubkey,
             local_payment_basepoint, remote_payment_basepoint,
             local_revocation_pubkey, local_delayedpubkey,
-            funding_tx_id, funding_output_index, funding_amount_satoshi)
+            funding_tx_id, funding_output_index, funding_amount_satoshi,
+            to_local_msat, to_remote_msat, local_feerate_per_kw)
         our_commit_tx.sign({bh2u(local_funding_pubkey): (local_funding_privkey[:-1], True)})
         ref_commit_tx_str = '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'
         ref_commit_tx = Transaction(ref_commit_tx_str)
@@ -50,7 +51,7 @@ class Test_LNBase(unittest.TestCase):
         pubkeys, _x_pubkeys = our_commit_tx.get_sorted_pubkeys(our_commit_tx.inputs()[0])
         index_of_pubkey = pubkeys.index(bh2u(remote_funding_pubkey))
         our_commit_tx._inputs[0]["signatures"][index_of_pubkey] = remote_signature + "01"
-
+        print("our tx", str(our_commit_tx))
         print("Reference inputs", json.dumps(ref_commit_tx.inputs(), indent=2))
         print("Our inputs", json.dumps(our_commit_tx.inputs(), indent=2))
 
@@ -64,8 +65,8 @@ class Test_LNBase(unittest.TestCase):
         output2adr = ref_commit_tx.outputs()[1][1]
         self.assertTrue(bitcoin.redeem_script_to_address("p2wsh", "63210212a140cd0c6539d07cd08dfe09984dec3251ea808b892efeac3ede9402bf2b1967029000b2752103fd5960528dc152014952efdb702a88f71e3c1653b2314431701ec77e57fde83c68ac") in [output1adr, output2adr])
         # todo check order and other output
-
         self.assertEqual(str(our_commit_tx), ref_commit_tx_str)
+
     def commitment_tx_with_all_five_HTLCs_untrimmed_minimum_feerate(self):
         to_local_msat = 6988000000
         to_remote_msat = 3000000000