We will use this helper in later commits to detect witness stripping without having
to execute every input Script three times in a row.
Github-Pull: #33105
Rebased-From: 2907b58834
Let's say an attacker wants to use/exhaust the network's bandwidth, and
has the choice between renting resources from a commercial provider and
getting the network to "spam" itself it by sending unconfirmed
transactions. We'd like the latter to be more expensive than the former.
The bandwidth for relaying a transaction across the network is roughly
its serialized size (plus relay overhead) x number of nodes. A 1000vB
transaction is 1000-4000B serialized. With 100k nodes, that's 0.1-0.4GB
If the going rate for commercial services is 10c/GB, that's like 1-4c per kvB
of transaction data, so a 1000vB transaction should pay at least $0.04.
At a price of 120k USD/BTC, 100sat is about $0.12. This price allows us
to tolerate a large decrease in the conversion rate or increase in the
number of nodes.
Github-Pull: #33106
Rebased-From: 6da5de58ca
Back when we implemented coin age priority as a miner policy, miners
mempools might admit transactions paying very low fees, but then want to
set a higher fee for block inclusion. However, since coin age priority
was removed in v0.15, the block assembly policy is solely based on fees,
so we do not need to apply minimum feerate rules in multiple places. In
fact, the block assembly policy ignoring transactions that are added to
the mempool is likely undesirable as we waste resources accepting and
storing this transaction.
Instead, rely on mempool policy to enforce a minimum entry feerate to
the mempool (minrelaytxfee). Set the minimum block feerate to the
minimum non-zero amount (1sat/kvB) so it collects everything it finds in
mempool into the block.
Github-Pull: #33106
Rebased-From: 5f2df0ef78
The Consensus Cleanup soft fork proposal includes a limit on the number of legacy signature
operations potentially executed when validating a transaction. If this change is to be implemented
here and activated by Bitcoin users in the future, we should prevent the ability for someone to
broadcast a transaction through the p2p network that is not valid according to the new rules. This
is because if it was possible it would be a trivial DoS to potentially unupgraded miners after the
soft fork activates.
We do not know for sure whether users will activate the Consensus Cleanup. However if they do such
transactions must have been made non-standard long in advance, due to the time it takes for most
nodes on the network to upgrade. In addition this limit may only be run into by pathological
transactions which pad the Script with sigops but do not use actual signatures when spending, as
otherwise they would run into the standard transaction size limit.
Github-Pull: bitcoin/bitcoin#32521
Rebased-From: 5863315e33
- This commit renamed coinbase_max_additional_weight to block_reserved_weight.
- Also clarify that the reservation is for block header, transaction count
and coinbase transaction.
3e0a992a3f doc: Clarify comments about endianness after #30526 (Ryan Ofsky)
Pull request description:
This is a documentation-only change following up on suggestions made in the #30526 review.
Motivation for this change is that I was recently reviewing #31583, which reminded me how confusing the arithmetic blob code was and made me want to write better comments.
ACKs for top commit:
achow101:
ACK 3e0a992a3f
TheCharlatan:
ACK 3e0a992a3f
Sjors:
ACK 3e0a992a3f
BrandonOdiwuor:
LGTM ACK 3e0a992a3f
Tree-SHA512: 90d5582a25a51fc406d83ca6b8c4e5e4d3aee828a0497f4b226b2024ff89e29b9b50d0ae8ddeac6abf2757fe78548d58cf3dd54df4b6d623f634a2106048091d
This is a documentation-only change following up on suggestions made in the
#30526 review.
Motivation for this change is that I was recently reviewing #31583, which
reminded me how confusing the arithmetic blob code was and made me want to
write better comments.
Also known as Ephemeral Dust.
We try to ensure that dust is spent in blocks by requiring:
- ephemeral dust tx is 0-fee
- ephemeral dust tx only has one dust output
- If the ephemeral dust transaction has a child,
the dust is spent by by that child.
0-fee requirement means there is no incentive to mine
a transaction which doesn't have a child bringing its
own fees for the transaction package.
Also, remove not needed and possibly redundant function name and class
names from the log string. Also, minimally reword the log messages.
Also, remove redundant trailing newlines from log messages, while
touching.
There is no need to compare the field to CLIENT_VERSION. Either the
format remains compatible and the value can be left unchanged, or it is
incompatible and the value needs to be increased to at least 289900+1.
Keep mentions of v3 in debug strings to help people who might not know
that TRUC is applied when version=3.
Also keep variable names in tests, as it is less verbose to keep v3 and v2.
94ed4fbf8e Add release note for size 2 package rbf (Greg Sanders)
afd52d8e63 doc: update package RBF comment (Greg Sanders)
6e3c4394cf mempool: Improve logging of replaced transactions (Greg Sanders)
d3466e4cc5 CheckPackageMempoolAcceptResult: Check package rbf invariants (Greg Sanders)
316d7b63c9 Fuzz: pass mempool to CheckPackageMempoolAcceptResult (Greg Sanders)
4d15bcf448 [test] package rbf (glozow)
dc21f61c72 [policy] package rbf (Suhas Daftuar)
5da3967815 PackageV3Checks: Relax assumptions (Greg Sanders)
Pull request description:
Allows any 2 transaction package with no in-mempool ancestors to do package RBF when directly conflicting with other mempool clusters of size two or less.
Proposed validation steps:
1) If the transaction package is of size 1, legacy rbf rules apply.
2) Otherwise the transaction package consists of a (parent, child) pair with no other in-mempool ancestors (or descendants, obviously), so it is also going to create a cluster of size 2. If larger, fail.
3) The package rbf may not evict more than 100 transactions from the mempool(bip125 rule 5)
4) The package is a single chunk
5) Every directly conflicted mempool transaction is connected to at most 1 other in-mempool transaction (ie the cluster size of the conflict is at most 2).
6) Diagram check: We ensure that the replacement is strictly superior, improving the mempool
7) The total fee of the package, minus the total fee of what is being evicted, is at least the minrelayfee * size of the package (equivalent to bip125 rule 3 and 4)
Post-cluster mempool this will likely be expanded to general package rbf, but this is what we can safely support today.
ACKs for top commit:
achow101:
ACK 94ed4fbf8e
glozow:
reACK 94ed4fbf8e via range-diff
ismaelsadeeq:
re-ACK 94ed4fbf8e
theStack:
Code-review ACK 94ed4fbf8e
murchandamus:
utACK 94ed4fbf8e
Tree-SHA512: 9bd383e695964f362f147482bbf73b1e77c4d792bda2e91d7f30d74b3540a09146a5528baf86854a113005581e8c75f04737302517b7d5124296bd7a151e3992
Relax assumptions about in-mempool children of in-mempool
parents. With package RBF, we will allow a package of size
2 with conflicts on its parent and reconsider the parent
if its fee is insufficient on its own.
Consider:
TxA (in mempool) <- TxB (in mempool)
TxA (in mempool) <- TxB' (in package, conflicts with TxB) <-
TxC (in package)
If TxB' fails to RBF TxB due to insufficient feerate, the
package TxB' + TxC will be considered. PackageV3Checks
called on TxB' will see an in-mempool parent TxA, and
see the in-mempool child TxB. We cannot assume there is
no in-mempool sibling, rather detect it and fail normally.
Prior to package RBF, this would have failed on the first
conflict in package.
In order to ensure that the change of nVersion to a uint32_t in the
previous commit has no effect, rename nVersion to version in this commit
so that reviewers can easily spot if a spot was missed or if there is a
check somewhere whose semantics have changed.
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.
ACKs for top commit:
sdaftuar:
ACK 154b2b2296
achow101:
ACK 154b2b2296
instagibbs:
ACK 154b2b2296
t-bast:
ACK 154b2b2296
murchandamus:
crACK 154b2b2296
Tree-SHA512: 89392a460908a8ea9f547d90e00f5181de0eaa9d2c4f2766140a91294ade3229b3d181833cad9afc93a0d0e8c4b96ee2f5aeda7c50ad7e6f3a8320b9e0c5ae97
ffc674595c Replace remaining "520" magic numbers with MAX_SCRIPT_ELEMENT_SIZE (Jon Atack)
Pull request description:
Noticed these while reviewing BIPs yesterday.
It would be clearer and more future-proof to refer to their constant name.
ACKs for top commit:
instagibbs:
ACK ffc674595c
sipa:
ACK ffc674595c
achow101:
ACK ffc674595c
glozow:
ACK ffc674595c, agree it's clearer for these comments to refer to the greppable name of the limit rather than the number
Tree-SHA512: 462afc1c64543877ac58cb3acdb01d42c6d08abfb362802f29f3482d75401a2a8adadbc2facd222a9a9fefcaab6854865ea400f50ad60bec17831d29f7798afe
e518a8bf8a [functional test] opportunistic 1p1c package submission (glozow)
87c5c524d6 [p2p] opportunistically accept 1-parent-1-child packages (glozow)
6c51e1d7d0 [p2p] add separate rejections cache for reconsiderable txns (glozow)
410ebd6efa [fuzz] break out parent functions and add GetChildrenFrom* coverage (glozow)
d095316c1c [unit test] TxOrphanage::GetChildrenFrom* (glozow)
2f51cd680f [txorphanage] add method to get all orphans spending a tx (glozow)
092c978a42 [txpackages] add canonical way to get hash of package (glozow)
c3c1e15831 [doc] restore comment about why we check if ptx HasWitness before caching rejected txid (glozow)
6f4da19cc3 guard against MempoolAcceptResult::m_replaced_transactions (glozow)
Pull request description:
This enables 1p1c packages to propagate in the "happy case" (i.e. not reliable if there are adversaries) and contains a lot of package relay-related code. See https://github.com/bitcoin/bitcoin/issues/27463 for overall package relay tracking.
Rationale: This is "non-robust 1-parent-1-child package relay" which is immediately useful.
- Relaying 1-parent-1-child CPFP when mempool min feerate is high would be a subset of all package relay use cases, but a pretty significant improvement over what we have today, where such transactions don't propagate at all. [1]
- Today, a miner can run this with a normal/small maxmempool to get revenue from 1p1c CPFP'd transactions without losing out on the ones with parents below mempool minimum feerate.
- The majority of this code is useful for building more featureful/robust package relay e.g. see the code in #27742.
The first 2 commits are followups from #29619:
- https://github.com/bitcoin/bitcoin/pull/29619#discussion_r1523094034
- https://github.com/bitcoin/bitcoin/pull/29619#discussion_r1519819257
Q: What makes this short of a more full package relay feature?
(1) it only supports packages in which 1 of the parents needs to be CPFP'd by the child. That includes 1-parent-1-child packages and situations in which the other parents already pay for themselves (and are thus in mempool already when the package is submitted). More general package relay is a future improvement that requires more engineering in mempool and validation - see #27463.
(2) We rely on having kept the child in orphanage, and don't make any attempt to protect it while we wait to receive the parent. If we are experiencing a lot of orphanage churn (e.g. an adversary is purposefully sending us a lot of transactions with missing inputs), we will fail to submit packages. This limitation has been around for 12+ years, see #27742 which adds a token bucket scheme for protecting package-related orphans at a limited rate per peer.
(3) Our orphan-handling logic is somewhat opportunistic; we don't make much effort to resolve an orphan beyond asking the child's sender for the parents. This means we may miss packages if the first sender fails to give us the parent (intentionally or unintentionally). To make this more robust, we need receiver-side logic to retry orphan resolution with multiple peers. This is also an existing problem which has a proposed solution in #28031.
[1]: see this writeup and its links 02ec218c78/bip-0331.mediawiki (propagate-high-feerate-transactions)
ACKs for top commit:
sr-gi:
tACK e518a8bf8a
instagibbs:
reACK e518a8bf8a
theStack:
Code-review ACK e518a8bf8a📦
dergoegge:
light Code review ACK e518a8bf8a
achow101:
ACK e518a8bf8a
Tree-SHA512: 632579fbe7160cb763bbec6d82ca0dab484d5dbbc7aea90c187c0b9833b8d7c1e5d13b8587379edd3a3b4a02a5a1809020369e9cd09a4ebaf729921f65c15943
