ba84a25dee [doc] update mempool-replacements.md for incremental relay feerate change (glozow)
18720bc5d5 [doc] release note for min feerate changes (glozow)
6da5de58ca [policy] lower default minrelaytxfee and incrementalrelayfee to 100sat/kvB (glozow)
2e515d2897 [prep/test] make wallet_fundrawtransaction's minrelaytxfee assumption explicit (glozow)
457cfb61b5 [prep/util] help MockMempoolMinFee handle more precise feerates (glozow)
3eab8b7240 [prep/test] replace magic number 1000 with respective feerate vars (glozow)
5f2df0ef78 [miner] lower default -blockmintxfee to 1sat/kvB (glozow)
d6213d6aa1 [doc] assert that default min relay feerate and incremental are the same (glozow)
1fbee5d7b6 [test] explicitly check default -minrelaytxfee and -incrementalrelayfee (glozow)
72dc18467d [test] RBF rule 4 for various incrementalrelayfee settings (glozow)
85f498893f [test] check bypass of minrelay for various minrelaytxfee settings (glozow)
e5f896bb1f [test] check miner doesn't select 0fee transactions (glozow)
Pull request description:
ML post for discussion about the general concept, how this impacts the wider ecosystem, philosophy about minimum feerates, etc: https://delvingbitcoin.org/t/changing-the-minimum-relay-feerate/1886
This PR is inspired by #13922 and #32959 to lower the minimum relay feerate in response to bitcoin's exchange rate changes in the last ~10 years. It lowers the default `-minrelaytxfee` and `-incrementalrelayfee`, and knocks `-blockmintxfee` down to the minimum nonzero setting. Also adds some tests for the settings and pulls in #32750.
The minimum relay feerate is a DoS protection rule, representing a price on the network bandwidth used to relay transactions that have no PoW. While relay nodes don't all collect fees, the assumption is that if nodes on the network use their resources to relay this transaction, it will reach a miner and the attacker's money will be spent once it is mined. The incremental relay feerate is similar: it's used to price the relay of replacement transactions (the additional fees need to cover the new transactions at this feerate) and evicted transactions (following a trim, the new mempool minimum feerate is the package feerate of what was removed + incremental).
Also note that many nodes on the network have elected to relay/mine lower feerate transactions. Miners (some say up to 85%) are choosing to mine these low feerate transactions instead of leaving block space unfilled, but these blocks have extremely poor compact block reconstruction rates with nodes that rejected or didn't hear about those transactions earlier.
- https://github.com/bitcoin/bitcoin/pull/33106#issuecomment-3155627414
- https://x.com/caesrcd/status/1947022514267230302
- https://mempool.space/block/00000000000000000001305770e0aa279dcd8ba8be18c3d5cf736a26f77e06fd
- https://mempool.space/block/00000000000000000001b491649ec030aa8e003e1f4f9d3b24bb99ba16f91e97
- https://x.com/mononautical/status/1949452586391855121
While it wouldn't make sense to loosen DoS restrictions recklessly in response to these events, I think the current price is higher than necessary, and this motivates us changing the default soon. Since the minimum relay feerate defines an amount as too small based on what it costs the attacker, it makes sense to consider BTC's conversion rate to what resources you can buy in the "real world."
Going off of [this comment](https://github.com/bitcoin/bitcoin/pull/32959#issuecomment-3095260286) and [this comment](https://github.com/bitcoin/bitcoin/pull/33106#issuecomment-3142444090)
- 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 ec2 bandwidth is 10c/GB, that's like 1-4c per kvB of transaction data
- Then a 1000vB transaction should pay at least 4c
- $0.04 USD is 40 satoshis at 100k USD/BTC
- Baking in some margin for changes in USD/BTC conversion rate, number of nodes (and thus bandwidth), and commercial service costs, I think 50-100 satoshis is on the conservative end but in the right ballpark
- At least 97% of the recent sub-1sat/vB transactions would be accepted with a new threshold of 0.1sat/vB: https://github.com/bitcoin/bitcoin/pull/33106#issuecomment-3156213089
List of feerates that are changed and why:
- min relay feerate: significant conversion rate changes, see above
- incremental relay feerate: should follow min relay feerate, see above
- block minimum feerate: shouldn’t be above min relay feerate, otherwise the node accepts transactions it will never mine. I've knocked it down to the bare minimum of 1sat/kvB. Now that we no longer have coin age priority (removed in v0.15), I think we can leave it to the `CheckFeeRate` policy rule to enforce a minimum entry price, and the block assembly code should just fill up the block with whatever it finds in mempool.
List of feerates that are not changed and why:
- dust feerate: this feerate cannot be changed as flexibly as the minrelay feerate. A much longer record of low feerate transactions being mined is needed to motivate a decrease there.
- maxfeerate (RPC, wallet): I think the conversion rate is relevant as well, but out of scope for this PR
- minimum feerate returned by fee estimator: should be done later. In the past, we've excluded new policy defaults from fee estimation until we feel confident they represent miner policy (e.g. #9519). Also, the fee estimator itself doesn't have support for sub-1sat/vB yet.
- all wallet feerates (mintxfee, fallbackfee, discardfee, consolidatefeerate, WALLET_INCREMENTAL_RELAY_FEE, etc.): should be done later. Our standard procedure is to do wallet changes at least 1 release after policy changes.
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ACK ba84a25dee
davidgumberg:
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w0xlt:
ACK ba84a25dee
caesrcd:
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ismaelsadeeq:
re-ACK ba84a25dee
Tree-SHA512: b4c35e8b506b1184db466551a7e2e48bb1e535972a8dbcaa145ce3a8bfdcc70a8807dc129460f129a9d31024174d34077154a387c32f1a3e6831f6fa5e9c399e
de0675f9de refactor: Move `transaction_identifier.h` to primitives (marcofleon)
6f068f65de Remove implicit uint256 conversion and comparison (marcofleon)
9c24cda72e refactor: Convert remaining instances from uint256 to Txid (marcofleon)
d2ecd6815d policy, refactor: Convert uint256 to Txid (marcofleon)
f6c0d1d231 mempool, refactor: Convert uint256 to Txid (marcofleon)
aeb0f78330 refactor: Convert `mini_miner` from uint256 to Txid (marcofleon)
326f244724 refactor: Convert RPCs and `merkleblock` from uint256 to Txid (marcofleon)
49b3d3a92a Clean up `FindTxForGetData` (marcofleon)
Pull request description:
This is the final leg of the [type safety refactor](https://github.com/bitcoin/bitcoin/pull/32189).
All of these changes are straightforward `uint256` --> `Txid` along with any necessary explicit conversions. Also, `transaction_identifier.h` is moved to primitives in the last commit, as `Txid` and `Wtxid` become fundamental types after this PR.
ACKs for top commit:
stickies-v:
re-ACK de0675f9de, no changes since a20724d926d5844168c6a13fa8293df8c8927efe except address review nits.
janb84:
re ACK de0675f9de
dergoegge:
re-ACK de0675f9de
theStack:
Code-review ACK de0675f9de
Tree-SHA512: 2413160fca7ab146a8d79d18ce3afcf7384cacc73c513d41928904aa453b4dd7a350064cee71e9c5d015da5904c7c81ac17603e50a47441ebc5b0c653235dd08
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.
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.
d3b8a54a81 Refactor CFeeRate to use FeeFrac internally (Pol Espinasa)
Pull request description:
The `FeeFrac` type represents a fraction, intended to be used for `sats/vbyte` or `sats/WU`. It was added to improve accuracy when evaluating fee rates in cluster mempool. [1]
But it can also be used to fix the precision issues that the current `CFeeRate` class has now.
At the moment, `CFeeRate` handles the fee rate as satoshis per kilovirtualbyte: `CAmount / kvB` using an integer.
This PR fix `CFeeRate` precision issues by encapsulating `FeeFrac` internally keeping backwards compatibility.
This PR can also be used as a based to use multiple units on RPC calls as detailed in this issue [2].
Some previous discussions:
[1] https://github.com/bitcoin/bitcoin/pull/30535
[2] https://github.com/bitcoin/bitcoin/issues/32093
ACKs for top commit:
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murchandamus:
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ismaelsadeeq:
re-ACK d3b8a54a81📦
theStack:
Code-review ACK d3b8a54a81
Tree-SHA512: 5a8149d81e82ad4e60a0e76ff6a82a5b1c4e212cf5156c1cdd16bf9acbb351e7be458eac3f0a2ae89107f331062b299c1d9ca649d3b820ad0b68e6d1a14292e5
27aefac425 validation: detect witness stripping without re-running Script checks (Antoine Poinsot)
2907b58834 policy: introduce a helper to detect whether a transaction spends Segwit outputs (Antoine Poinsot)
eb073209db qa: test witness stripping in p2p_segwit (Antoine Poinsot)
Pull request description:
Since it was introduced in 4eb515574e (#18044), the detection of a stripped witness relies on running the Script checks 3 times. In the worst case, this consists in running Script validation for every single input 3 times.
Detection of a stripped witness is necessary because in this case wtxid==txid, and the transaction's wtxid must not be added to the reject filter or it could allow a malicious peer to interfere with txid-based orphan resolution as used in 1p1c package relay.
However it is not necessary to run Script validation to detect a stripped witness (much less so doing it 3 times in a row). There are 3 types of witness program: defined program types (Taproot, P2WPKH and P2WSH), undefined types, and the Pay-to-anchor carve-out.
For defined program types, Script validation with an empty witness will always fail (by consensus). For undefined program types, Script validation is always going to fail regardless of the witness (by standardness). For P2A, an empty witness is never going to lead to a failure.
Therefore it holds that we can always detect a stripped witness without re-running Script validation. However this might lead to more "false positives" (cases where we return witness stripping for an otherwise invalid transaction) than the existing implementation. For instance a transaction with one P2PKH input with an invalid signature and one P2WPKH input with its witness stripped. The existing implementation would treat it as consensus invalid while the implementation in this PR would always consider it witness stripped.
h/t AJ: this essentially implements a variant of https://github.com/bitcoin/bitcoin/pull/33066#issuecomment-3135258539.
ACKs for top commit:
sipa:
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Crypt-iQ:
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glozow:
reACK 27aefac425
Tree-SHA512: 70cf76b655b52bc8fa2759133315a3f11140844b6b80d9de3c95f592050978cc01a87bd2446e3a9c25cc872efea7659d6da3337b1a709511771fece206e9f149
ea17a9423f [doc] release note for relaxing requirement of all unconfirmed parents present (glozow)
12f48d5ed3 test: add chained 1p1c propagation test (Greg Sanders)
525be56741 [unit test] package submission 2p1c with 1 parent missing (glozow)
f24771af05 relax child-with-unconfirmed-parents rule (glozow)
Pull request description:
Broadens the package validation interface, see #27463 for wider context.
On master, package rules include that (1) the package topology must be child-wth-parents (2) all of the child's unconfirmed parents must be present. This PR relaxes the second rule, leaving the first rule untouched (there are plans to change that as well, but not here).
Original motivation for this rule was based on the idea that we would have a child-with-unconfirmed-parents package relay protocol, and this would verify that the peer provided the "correct" package. For various reasons, we're not planning on doing this. We could potentially do this for ancestor packages (with a similar definition that all UTXOs to make the tx valid are available in this package), but it's also questionable whether it's useful to enforce this.
This rule gets in the way of certain usage of 1p1c package relay currently. If a transaction has multiple parents, of which only 1 requires a package CPFP, this rule blocks the package from relaying. Even if all the non-low-feerate parents are already in mempool, when the p2p logic submits the 1p1c package, it gets rejected for not meeting this rule.
ACKs for top commit:
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Tree-SHA512: c2231761ae7b2acea10a96735e7a36c646f517964d0acb59bacbae1c5a1950e0223458b84c6d5ce008f0c1d53c1605df0fb3cd0064ee535ead006eb7c0fa625b
This rule was originally introduced along with a very early proposal for
package relay as a way to verify that the "correct"
child-with-unconfirmed-parents package was provided for a transaction,
where correctness was defined as all of the transactions unconfirmed
parents. However, we are not planning to introduce a protocol where
peers would be asked to send these packages.
This rule has downsides: if a transaction has multiple parents but only
1 that requires package CPFP to be accepted, the current rule prevents
us from accepting that package. Even if the other parents are already in
mempool, the p2p logic will only submit the 1p1c package, which fails
this check. See the test in p2p_1p1c_network.py
96da68a38f qa: functional test a transaction running into the legacy sigop limit (Antoine Poinsot)
367147954d qa: unit test standardness of inputs packed with legacy sigops (Antoine Poinsot)
5863315e33 policy: make pathological transactions packed with legacy sigops non-standard. (Antoine Poinsot)
Pull request description:
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 make transactions that are not valid
according to the new rules non-standard first because it would otherwise be a trivial DoS to
potentially unupgraded miners after the soft fork activates.
ML post: https://gnusha.org/pi/bitcoindev/49dyqqkf5NqGlGdinp6SELIoxzE_ONh3UIj6-EB8S804Id5yROq-b1uGK8DUru66eIlWuhb5R3nhRRutwuYjemiuOOBS2FQ4KWDnEh0wLuA=@protonmail.com/T/#u
ACKs for top commit:
instagibbs:
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maflcko:
review ACK 96da68a38f🚋
achow101:
ACK 96da68a38f
glozow:
light code review ACK 96da68a38f, looks correct to me
Tree-SHA512: 106ffe62e48952affa31c5894a404a17a3b4ea8971815828166fba89069f757366129f7807205e8c6558beb75c6f67d8f9a41000be2f8cf95be3b1a02d87bfe9
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.
a60f863d3e scripted-diff: Replace GenTxidVariant with GenTxid (marcofleon)
c8ba199598 Remove old GenTxid class (marcofleon)
072a198ea4 Convert remaining instances of GenTxid to GenTxidVariant (marcofleon)
1b528391c7 Convert `txrequest` to GenTxidVariant (marcofleon)
bde4579b07 Convert `txdownloadman_impl` to GenTxidVariant (marcofleon)
c876a892ec Replace GenTxid with Txid/Wtxid overloads in `txmempool` (marcofleon)
de858ce2be move-only: make GetInfo a private CTxMemPool member (stickies-v)
eee473d9f3 Convert `CompareInvMempoolOrder` to GenTxidVariant (marcofleon)
243553d590 refactor: replace get_iter_from_wtxid with GetIter(const Wtxid&) (stickies-v)
fcf92fd640 refactor: make CTxMemPool::GetIter strongly typed (marcofleon)
11d28f21bb Implement GenTxid as a variant (marcofleon)
Pull request description:
Part of the [type safety refactor](https://github.com/bitcoin/bitcoin/pull/32189).
This PR changes the GenTxid class to a variant, which holds both Txids and Wtxids. This provides compile-time type safety and eliminates the manual type check (bool m_is_wtxid). Variables that can be either a Txid or a Wtxid are now using the new GenTxid variant, instead of uint256.
ACKs for top commit:
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maflcko:
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theStack:
Code-review ACK a60f863d3e
Tree-SHA512: da9b73b7bdffee2eb9281a409205519ac330d3336094d17681896703fbca8099608782c9c85801e388e4d90af5af8abf1f34931f57bbbe6e9674d802d6066047
There is no way to report a close error from `AutoFile` destructor.
Such an error could be serious if the file has been written to because
it may mean the file is now corrupted (same as if write fails).
So, change all users of `AutoFile` that use it to write data to
explicitly close the file and handle a possible error.
Datacarrier output script sizes and output counts are now
uncapped by default.
To avoid introducing another startup argument, we modify the
OP_RETURN accounting to "budget" the spk sizes.
If a user has set a custom default, this results in that
budget being spent over the sum of all OP_RETURN outputs'
scripts in the transaction, no longer capping the number
of OP_RETURN outputs themselves. This should allow a
superset of current behavior while respecting the passed
argument in terms of total arbitrary data storage.
Co-authored-by: Anthony Towns <aj@erisian.com.au>
Closes: #11800
Note: In certain rare edge cases, monotonically increasing estimates may
not be guaranteed. Specifically, given two targets N and M, where M > N,
if a sub-estimate for target N fails to return a valid fee rate, while
target M has valid fee rate for that sub-estimate, target M may result
in a higher fee rate estimate than target N.
See: https://github.com/bitcoin/bitcoin/issues/11800#issuecomment-349697807
Historically, the headers have been bumped some time after a file has
been touched. Do it now to avoid having to touch them again in the
future for that reason.
-BEGIN VERIFY SCRIPT-
sed -i --regexp-extended 's;( 20[0-2][0-9])(-20[0-2][0-9])? The Bitcoin Core developers;\1-present The Bitcoin Core developers;g' $( git show --pretty="" --name-only HEAD~1 )
-END VERIFY SCRIPT-
- 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:
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TheCharlatan:
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Sjors:
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BrandonOdiwuor:
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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.
