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Merge bitcoin/bitcoin#29873: policy: restrict all TRUC (v3) transactions to 10kvB

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154b2b2296 [fuzz] V3_MAX_VSIZE and effective ancestor/descendant size limits (glozow)
a29f1df289 [policy] restrict all v3 transactions to 10kvB (glozow)
d578e2e354 [policy] explicitly require non-v3 for CPFP carve out (glozow)

Pull request description:

  Opening for discussion / conceptual review.

  We like the idea of a smaller maximum transaction size because:
  - It lowers potential replacement cost (i.e. harder to do Rule 3 pinning via gigantic transaction)
  - They are easier to bin-pack in block template production
  - They equate to a tighter memory limit in data structures that are bounded by a number of transactions (e.g. orphanage and vExtraTxnForCompact). For example, the current memory bounds for orphanage is 100KvB * 100 = 40MB, and guaranteeing 1 tx per peer would require reserving a pretty large space.

  History for `MAX_STANDARD_TX_WEIGHT=100KvB` (copied from https://github.com/bitcoin/bitcoin/pull/29873#issuecomment-2115459510):
  - 2010-09-13 In 3df62878c3 satoshi added a 100kB (MAX_BLOCK_SIZE_GEN/5 with MBS_GEN = MAX_BLOCK_SIZE/2) limit on new transactions in CreateTransaction()
  - 2013-02-04 https://github.com/bitcoin/bitcoin/pull/2273 In gavin gave that constant a name, and made it apply to transaction relay as well

  Lowering `MAX_STANDARD_TX_WEIGHT` for all txns is not being proposed, as there are existing apps/protocols that rely on large transactions. However, it's been brought up that we should consider this for TRUCs (which is especially designed to avoid Rule 3 pinning).

  This reduction should be ok because using nVersion=3 isn't standard yet, so this wouldn't break somebody's existing use case. If we find that this is too small, we can always increase it later. Decreasing would be much more difficult.
  ~[Expected size of a commitment transaction](https://github.com/lightning/bolts/blob/master/03-transactions.md#expected-weight-of-the-commitment-transaction) is within (900 + 172 * 483 + 224) / 4 = 21050vB~ EDIT: this is incorrect, but perhaps not something that should affect how we choose this number.

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  achow101:
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  instagibbs:
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  t-bast:
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  murchandamus:
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Tree-SHA512: 89392a460908a8ea9f547d90e00f5181de0eaa9d2c4f2766140a91294ade3229b3d181833cad9afc93a0d0e8c4b96ee2f5aeda7c50ad7e6f3a8320b9e0c5ae97
This commit is contained in:
Ava Chow
2024-05-23 11:54:18 -04:00
parent 6300438a2e 154b2b2296
commit 867f6af803
5 changed files with 76 additions and 11 deletions
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57
test/functional/mempool_accept_v3.py
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@@ -6,6 +6,7 @@ from decimal import Decimal
from test_framework.messages import (
MAX_BIP125_RBF_SEQUENCE,
WITNESS_SCALE_FACTOR,
)
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import (
@@ -21,6 +22,7 @@ from test_framework.wallet import (
)
MAX_REPLACEMENT_CANDIDATES = 100
V3_MAX_VSIZE = 10000
def cleanup(extra_args=None):
def decorator(func):
@@ -49,6 +51,20 @@ class MempoolAcceptV3(BitcoinTestFramework):
assert_equal(len(txids), len(mempool_contents))
assert all([txid in txids for txid in mempool_contents])
@cleanup(extra_args=["-datacarriersize=20000", "-acceptnonstdtxn=1"])
def test_v3_max_vsize(self):
node = self.nodes[0]
self.log.info("Test v3-specific maximum transaction vsize")
tx_v3_heavy = self.wallet.create_self_transfer(target_weight=(V3_MAX_VSIZE + 1) * WITNESS_SCALE_FACTOR, version=3)
assert_greater_than_or_equal(tx_v3_heavy["tx"].get_vsize(), V3_MAX_VSIZE)
expected_error_heavy = f"v3-rule-violation, v3 tx {tx_v3_heavy['txid']} (wtxid={tx_v3_heavy['wtxid']}) is too big"
assert_raises_rpc_error(-26, expected_error_heavy, node.sendrawtransaction, tx_v3_heavy["hex"])
self.check_mempool([])
# Ensure we are hitting the v3-specific limit and not something else
tx_v2_heavy = self.wallet.send_self_transfer(from_node=node, target_weight=(V3_MAX_VSIZE + 1) * WITNESS_SCALE_FACTOR, version=2)
self.check_mempool([tx_v2_heavy["txid"]])
@cleanup(extra_args=["-datacarriersize=1000", "-acceptnonstdtxn=1"])
def test_v3_acceptance(self):
node = self.nodes[0]
@@ -201,10 +217,24 @@ class MempoolAcceptV3(BitcoinTestFramework):
"""
node = self.nodes[0]
self.log.info("Test that a decreased limitdescendantsize also applies to v3 child")
tx_v3_parent_large1 = self.wallet.send_self_transfer(from_node=node, target_weight=99900, version=3)
tx_v3_child_large1 = self.wallet.create_self_transfer(utxo_to_spend=tx_v3_parent_large1["new_utxo"], version=3)
# Child is within v3 limits, but parent's descendant limit is exceeded
assert_greater_than(1000, tx_v3_child_large1["tx"].get_vsize())
parent_target_weight = 9990 * WITNESS_SCALE_FACTOR
child_target_weight = 500 * WITNESS_SCALE_FACTOR
tx_v3_parent_large1 = self.wallet.send_self_transfer(
from_node=node,
target_weight=parent_target_weight,
version=3
)
tx_v3_child_large1 = self.wallet.create_self_transfer(
utxo_to_spend=tx_v3_parent_large1["new_utxo"],
target_weight=child_target_weight,
version=3
)
# Parent and child are within v3 limits, but parent's 10kvB descendant limit is exceeded
assert_greater_than_or_equal(V3_MAX_VSIZE, tx_v3_parent_large1["tx"].get_vsize())
assert_greater_than_or_equal(1000, tx_v3_child_large1["tx"].get_vsize())
assert_greater_than(tx_v3_parent_large1["tx"].get_vsize() + tx_v3_child_large1["tx"].get_vsize(), 10000)
assert_raises_rpc_error(-26, f"too-long-mempool-chain, exceeds descendant size limit for tx {tx_v3_parent_large1['txid']}", node.sendrawtransaction, tx_v3_child_large1["hex"])
self.check_mempool([tx_v3_parent_large1["txid"]])
assert_equal(node.getmempoolentry(tx_v3_parent_large1["txid"])["descendantcount"], 1)
@@ -212,10 +242,22 @@ class MempoolAcceptV3(BitcoinTestFramework):
self.log.info("Test that a decreased limitancestorsize also applies to v3 parent")
self.restart_node(0, extra_args=["-limitancestorsize=10", "-datacarriersize=40000", "-acceptnonstdtxn=1"])
tx_v3_parent_large2 = self.wallet.send_self_transfer(from_node=node, target_weight=99900, version=3)
tx_v3_child_large2 = self.wallet.create_self_transfer(utxo_to_spend=tx_v3_parent_large2["new_utxo"], version=3)
# Child is within v3 limits
tx_v3_parent_large2 = self.wallet.send_self_transfer(
from_node=node,
target_weight=parent_target_weight,
version=3
)
tx_v3_child_large2 = self.wallet.create_self_transfer(
utxo_to_spend=tx_v3_parent_large2["new_utxo"],
target_weight=child_target_weight,
version=3
)
# Parent and child are within v3 limits
assert_greater_than_or_equal(V3_MAX_VSIZE, tx_v3_parent_large2["tx"].get_vsize())
assert_greater_than_or_equal(1000, tx_v3_child_large2["tx"].get_vsize())
assert_greater_than(tx_v3_parent_large2["tx"].get_vsize() + tx_v3_child_large2["tx"].get_vsize(), 10000)
assert_raises_rpc_error(-26, f"too-long-mempool-chain, exceeds ancestor size limit", node.sendrawtransaction, tx_v3_child_large2["hex"])
self.check_mempool([tx_v3_parent_large2["txid"]])
@@ -585,6 +627,7 @@ class MempoolAcceptV3(BitcoinTestFramework):
node = self.nodes[0]
self.wallet = MiniWallet(node)
self.generate(self.wallet, 120)
self.test_v3_max_vsize()
self.test_v3_acceptance()
self.test_v3_replacement()
self.test_v3_bip125()