We optimistically pre-register a peer for txreconciliations
upon sending txreconciliation support announcement.
But if, at VERACK, we realize that the peer never sent
WTXIDRELAY message, we should unregister the peer
from txreconciliations, because txreconciliations rely on wtxids.
Once we received a reconciliation announcement support
message from a peer and it doesn't violate our protocol,
we store the negotiated parameters which will be used
for future reconciliations.
If we're connecting to the peer which might support
transaction reconciliation, we announce we want to reconcile
with them.
We store the reconciliation salt so that when the peer
responds with their salt, we are able to compute the
full reconciliation salt.
This behavior is enabled with a CLI flag.
a3789c700b Improve getpeerinfo pingtime, minping, and pingwait help docs (Jon Atack)
df660ddb1c Update getpeerinfo/-netinfo/TxRelay#m_relay_txs relaytxes docs (for v24 backport) (Jon Atack)
1f448542e7 Always return getpeerinfo "minfeefilter" field (for v24 backport) (Jon Atack)
9cd6682545 Make getpeerinfo field order consistent with its help (for v24 backport) (Jon Atack)
Pull request description:
Various updates and fixups, mostly targeting v24. Please refer to the commit messages for details.
ACKs for top commit:
achow101:
ACK a3789c700b
brunoerg:
ACK a3789c700b
vasild:
ACK a3789c700b
Tree-SHA512: b8586a9b83c1b18786b5ac1fc1dba91573c13225fc2cfc8d078f4220967c95056354f6be13327f33b4fcf3e9d5310fa4e1bdc93102cbd6574f956698993a54bf
Follow-up to #25717. The commit "Utilize anti-DoS headers download
strategy" changed how this bool variable is computed, so that its value
is now the opposite of what it should be.
to the current p2p behavior. We only initialize the Peer::TxRelay m_relay_txs
data structure if it isn't an outbound block-relay-only connection and fRelay=true
(the peer wishes to receive tx announcements) or we're offering NODE_BLOOM to this peer.
There are many cases where we assume message processing is
single-threaded in order for how we access node-related memory to be
safe. Add an explicit mutex that we can use to document this, which allows
the compiler to catch any cases where we try to access that memory from
other threads and break that assumption.
3add234546 ui: show header pre-synchronization progress (Pieter Wuille)
738421c50f Emit NotifyHeaderTip signals for pre-synchronization progress (Pieter Wuille)
376086fc5a Make validation interface capable of signalling header presync (Pieter Wuille)
93eae27031 Test large reorgs with headerssync logic (Suhas Daftuar)
355547334f Track headers presync progress and log it (Pieter Wuille)
03712dddfb Expose HeadersSyncState::m_current_height in getpeerinfo() (Suhas Daftuar)
150a5486db Test headers sync using minchainwork threshold (Suhas Daftuar)
0b6aa826b5 Add unit test for HeadersSyncState (Suhas Daftuar)
83c6a0c524 Reduce spurious messages during headers sync (Suhas Daftuar)
ed6cddd98e Require callers of AcceptBlockHeader() to perform anti-dos checks (Suhas Daftuar)
551a8d957c Utilize anti-DoS headers download strategy (Suhas Daftuar)
ed470940cd Add functions to construct locators without CChain (Pieter Wuille)
84852bb6bb Add bitdeque, an std::deque<bool> analogue that does bit packing. (Pieter Wuille)
1d4cfa4272 Add function to validate difficulty changes (Suhas Daftuar)
Pull request description:
New nodes starting up for the first time lack protection against DoS from low-difficulty headers. While checkpoints serve as our protection against headers that fork from the main chain below the known checkpointed values, this protection only applies to nodes that have been able to download the honest chain to the checkpointed heights.
We can protect all nodes from DoS from low-difficulty headers by adopting a different strategy: before we commit to storing a header in permanent storage, first verify that the header is part of a chain that has sufficiently high work (either `nMinimumChainWork`, or something comparable to our tip). This means that we will download headers from a given peer twice: once to verify the work on the chain, and a second time when permanently storing the headers.
The p2p protocol doesn't provide an easy way for us to ensure that we receive the same headers during the second download of peer's headers chain. To ensure that a peer doesn't (say) give us the main chain in phase 1 to trick us into permanently storing an alternate, low-work chain in phase 2, we store commitments to the headers during our first download, which we validate in the second download.
Some parameters must be chosen for commitment size/frequency in phase 1, and validation of commitments in phase 2. In this PR, those parameters are chosen to both (a) minimize the per-peer memory usage that an attacker could utilize, and (b) bound the expected amount of permanent memory that an attacker could get us to use to be well-below the memory growth that we'd get from the honest chain (where we expect 1 new block header every 10 minutes).
After this PR, we should be able to remove checkpoints from our code, which is a nice philosophical change for us to make as well, as there has been confusion over the years about the role checkpoints play in Bitcoin's consensus algorithm.
Thanks to Pieter Wuille for collaborating on this design.
ACKs for top commit:
Sjors:
re-tACK 3add234546
mzumsande:
re-ACK 3add234546
sipa:
re-ACK 3add234546
glozow:
ACK 3add234546
Tree-SHA512: e7789d65f62f72141b8899eb4a2fb3d0621278394d2d7adaa004675250118f89a4e4cb42777fe56649d744ec445ad95141e10f6def65f0a58b7b35b2e654a875
Delay sending SENDHEADERS (BIP 130) message until we know our peer's best
header's chain has more than nMinimumChainWork. This reduces inadvertent
headers messages received during initial headers sync due to block
announcements, which throw off our sync algorithm.
In order to prevent memory DoS, we must ensure that we don't accept a new
header into memory until we've performed anti-DoS checks, such as verifying
that the header is part of a sufficiently high work chain. This commit adds a
new argument to AcceptBlockHeader() so that we can ensure that all call-sites
which might cause a new header to be accepted into memory have to grapple with
the question of whether the header is safe to accept, or needs further
validation.
This patch also fixes two places where low-difficulty-headers could have been
processed without such validation (processing an unrequested block from the
network, and processing a compact block).
Credit to Niklas Gögge for noticing this issue, and thanks to Sjors Provoost
for test code.
Avoid permanently storing headers from a peer, unless the headers are part of a
chain with sufficiently high work. This prevents memory attacks using low-work
headers.
Designed and co-authored with Pieter Wuille.
This introduces an insignificant performance penalty, as it means locator
construction needs to use the skiplist-based CBlockIndex::GetAncestor()
function instead of the lookup-based CChain, but avoids the need for
callers to have access to a relevant CChain object.
eeee5ada23 Make adjusted time type safe (MacroFake)
fa3be799fe Add time helpers (MacroFake)
Pull request description:
This makes follow-ups easier to review. Also, it makes sense by itself.
ACKs for top commit:
ryanofsky:
Code review ACK eeee5ada23. Confirmed type changes and equivalent code changes only.
Tree-SHA512: 51bf1ae5428552177286113babdd49e82459d6c710a07b6e80a0a045d373cf51045ee010461aba98e0151d8d71b9b3b5f8f73e302d46ba4558e0b55201f99e9f
This is a refactor, putting the burden to think about thread safety to
the caller. Otherwise, there is a risk that the caller will assume
thread safety where none exists, as is evident in the previous two
commits.
f6a916683d Add functional test for block announcements during initial headers sync (Suhas Daftuar)
05f7f31598 Reduce bandwidth during initial headers sync when a block is found (Suhas Daftuar)
Pull request description:
On startup, if our headers chain is more than a day behind current time, we'll pick one peer to sync headers with until our best headers chain is caught up (at that point, we'll try to sync headers with all peers).
However, if an INV for a block is received before our headers chain is caught up, we'll then start to sync headers from each peer announcing the block. This can result in doing a big headers sync with many (if not all) of our peers simultaneously, which wastes bandwidth.
This PR would reduce that overhead by picking (at most) one new peer to try syncing headers with whenever a new block is announced, prior to our headers chain being caught up.
ACKs for top commit:
LarryRuane:
ACK f6a916683d
ajtowns:
ACK f6a916683d
mzumsande:
ACK f6a916683d
dergoegge:
Code review ACK f6a916683d
achow101:
ACK f6a916683d
Tree-SHA512: 0662000bd68db146f55981de4adc2e2b07cbfda222b1176569d61c22055e5556752ffd648426f69687ed1cc203105515e7304c12b915d6270df8e41a4a0e1eaa
If our headers chain is behind on startup, then if a block is found we'll try
to catch up from all peers announcing the block, in addition to our initial
headers-sync peer. This commit changes behavior so that in this situation,
we'll choose at most one peer announcing a block to additionally sync headers
from.
fadd8b2676 addrman: Use system time instead of adjusted network time (MarcoFalke)
Pull request description:
This changes addrman to use system time for address relay instead of the network adjusted time.
This is an improvement, because network time has multiple issues:
* It is non-monotonic, even if the system time is monotonic.
* It may be wrong, even if the system time is correct.
* It may be wrong, if the system time is wrong. For example, when the node has limited number of connections (`4`), or the system time is wrong by too much (more than +-70 minutes), or the system time only got wrong after timedata collected more than half of the entries while the time was correct, ...)
This may slightly degrade addr relay for nodes where timedata successfully adjusted the time. Addr relay can already deal with minor offsets of up to 10 minutes. Offsets larger than this should still allow addr relay and not result in a DoS.
ACKs for top commit:
dergoegge:
Code review ACK fadd8b2676
Tree-SHA512: b6c178fa01161544e5bc76c4cb23e11bcc30391f7b7a64accce864923766647bcfce2e8ae21d36fb1ffc1afa07bc46415aca612405bd8d4cc1f319c92a08498f
b4b657ba57 refactor: log `nEvicted` message in `LimitOrphans` then return void (chinggg)
Pull request description:
Fix https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=49347
LimitOrphans() can log expired tx and it should log evicted tx as well instead of returning the `nEvicted` number for caller to print the message.
Since `LimitOrphans()` now returns void, the redundant assertion check in fuzz test is also removed.
Top commit has no ACKs.
Tree-SHA512: 18c41702321b0e59812590cd389f3163831d431f4ebdc3b3e1e0698496a6bdbac52288f28f779237a58813c6717da1a35e8933d509822978ff726c1b13cfc778
`LimitOrphans()` can log expired tx and it should log evicted tx as well
instead of returning the number for caller to print the message.
Since `LimitOrphans()` now return void, the redundant assertion check in
fuzz test is also removed.
8d8eeb422e [net processing] Remove CNode::nLocalServices (John Newbery)
5961f8eea1 [net] Return CService from GetLocalAddrForPeer and GetLocalAddress (dergoegge)
d9079fe18d [net processing] Remove CNode::nServices (John Newbery)
7d1c036934 [net processing] Replace fHaveWitness with CanServeWitnesses() (John Newbery)
f65e83d51b [net processing] Remove fClient and m_limited_node (John Newbery)
fc5eb528f7 [tests] Connect peer in outbound_slow_chain_eviction by sending p2p messages (John Newbery)
1f52c47d5c [net processing] Add m_our_services and m_their_services to Peer (John Newbery)
Pull request description:
Another step in #19398. Which services we offer to a peer and which services they offer to us is application layer data and should not be stored on `CNode`.
This is also a prerequisite for adding `PeerManager` unit tests (See #25515).
ACKs for top commit:
MarcoFalke:
ACK 8d8eeb422e🔑
jnewbery:
utACK 8d8eeb422e
mzumsande:
Code Review ACK 8d8eeb422e
Tree-SHA512: e772eb2a0a85db346dd7b453a41011a12756fc7cbfda6a9ef6daa9633b9a47b9770ab3dc02377690f9d02127301c3905ff22905977f758bf90b17a9a35b37523
99f4785cad Replace GetTime() with NodeClock in MaybeSendGetHeaders() (Suhas Daftuar)
abf5d16c24 Don't send getheaders message when another request is outstanding (Suhas Daftuar)
ffe87db247 Cleanup received_new_header calculation to use WITH_LOCK (Suhas Daftuar)
6d95cd3e74 Move peer state updates from headers message into separate function (Suhas Daftuar)
2b341db731 Move headers direct fetch to end of ProcessHeadersMessage (Suhas Daftuar)
29c4518522 Move headers-direct-fetch logic into own function (Suhas Daftuar)
bf8ea6df75 Move additional headers fetching to own function (Suhas Daftuar)
9492e93bf9 Add helper function for checking header continuity (Suhas Daftuar)
7f2450871b Move handling of unconnecting headers into own function (Suhas Daftuar)
Pull request description:
Change `getheaders` messages so that we wait up to 2 minutes for a response to a prior `getheaders` message before issuing a new one.
Also change the handling of the `getheaders` message sent in response to a block INV, so that we no longer use the hashstop variable (including the hash stop will just mean that if our peer's headers chain is longer, then we won't learn
it, so there's no benefit to using hashstop).
Also, now respond to a `getheaders` during IBD with an empty headers message (rather than nothing) -- this better conforms to the intent of the new logic that it's better to not ignore a peer's `getheaders` message, even if you have nothing to give. This also avoids a lot of functional tests breaking.
This PR also reworks the headers processing logic to make it more readable.
ACKs for top commit:
ajtowns:
ACK 99f4785cad ; code review, check over new logic of when to send getheaders messages
dergoegge:
Code review ACK 99f4785cad
mzumsande:
Code Review ACK 99f4785cad
sipa:
utACK 99f4785cad
w0xlt:
tACK 99f4785cad Good improvement in the code.
Tree-SHA512: b8a63f6f71ac83e292edc0200def7835ad8b06b2955dd34e3ea6fac85980fa6962efd31d689ef5ea121ff5477ec14aafa4bbe2d0db134c05f4a31a57a8ced365
d1684beabe fees: Pass in a filepath instead of referencing gArgs (Carl Dong)
9a3d825c30 init: Remove redundant -*mempool*, -limit* queries (Carl Dong)
6c5c60c412 mempool: Use m_limit for UpdateTransactionsFromBlock (Carl Dong)
9e93b10301 node/ifaces: Use existing MemPoolLimits (Carl Dong)
38af2bcf35 mempoolaccept: Use limits from mempool in constructor (Carl Dong)
9333427014 mempool: Introduce (still-unused) MemPoolLimits (Carl Dong)
716bb5fbd3 scripted-diff: Rename anc/desc size limit vars to indicate SI unit (Carl Dong)
1ecc77321d scripted-diff: Rename DEFAULT_MEMPOOL_EXPIRY to indicate time unit (Carl Dong)
aa9141cd81 mempool: Pass in -mempoolexpiry instead of referencing gArgs (Carl Dong)
51c7a41a5e init: Only determine maxmempool once (Carl Dong)
386c9472c8 mempool: Make GetMinFee() with custom size protected (Carl Dong)
82f00de7a6 mempool: Pass in -maxmempool instead of referencing gArgs (Carl Dong)
f1941e8bfd pool: Add and use MemPoolOptions, ApplyArgsManOptions (Carl Dong)
0199bd35bb fuzz/rbf: Add missing TestingSetup (Carl Dong)
ccbaf546a6 scripted-diff: Rename DEFAULT_MAX_MEMPOOL_SIZE to indicate SI unit (Carl Dong)
fc02f77ca6 ArgsMan: Add Get*Arg functions returning optional (Carl Dong)
Pull request description:
This is part of the `libbitcoinkernel` project: #24303, https://github.com/bitcoin/bitcoin/projects/18
-----
As mentioned in the Stage 1 Step 2 description of [the `libbitcoinkernel` project](https://github.com/bitcoin/bitcoin/issues/24303), `ArgsManager` will not be part of `libbitcoinkernel`. Therefore, it is important that we remove any dependence on `ArgsManager` by code that will be part of `libbitcoinkernel`. This is the first in a series of PRs aiming to achieve this.
This PR removes `CTxMemPool+MempoolAccept`'s dependency on `ArgsManager` by introducing a `CTxMemPool::Options` struct, which is used to specify `CTxMemPool`'s various options at construction time.
These options are:
- `-maxmempool` -> `CTxMemPool::Options::max_size`
- `-mempoolexpiry` -> `CTxMemPool::Options::expiry`
- `-limitancestorcount` -> `CTxMemPool::Options::limits::ancestor_count`
- `-limitancestorsize` -> `CTxMemPool::Options::limits::ancestor_size`
- `-limitdescendantcount` -> `CTxMemPool::Options::limits::descendant_count`
- `-limitdescendantsize` -> `CTxMemPool::Options::limits::descendant_size`
More context can be gleaned from the commit messages. The important commits are:
- 56eb479ded8bfb2ef635bb6f3b484f9d5952c70d "pool: Add and use MemPoolOptions, ApplyArgsManOptions"
- a1e08b70f3068f4e8def1c630d8f50cd54da7832 "mempool: Pass in -maxmempool instead of referencing gArgs"
- 6f4bf3ede5812b374828f08fc728ceded2f10024 "mempool: Pass in -mempoolexpiry instead of referencing gArgs"
- 5958a7fe4806599fc620ee8c1a881ca10fa2dd16 "mempool: Introduce (still-unused) MemPoolLimits"
Reviewers: Help needed in the following commits (see commit messages):
- a1e08b70f3068f4e8def1c630d8f50cd54da7832 "mempool: Pass in -maxmempool instead of referencing gArgs"
- 0695081a797e9a5d7787b78b0f8289dafcc6bff7 "node/ifaces: Use existing MemPoolLimits"
Note to Reviewers: There are perhaps an infinite number of ways to architect `CTxMemPool::Options`, the current one tries to keep it simple, usable, and flexible. I hope we don't spend too much time arguing over the design here since that's not the point. In the case that you're 100% certain that a different design is strictly better than this one in every regard, please show us a fully-implemented branch.
-----
TODO:
- [x] Use the more ergonomic `CTxMemPool::Options` where appropriate
- [x] Doxygen comments for `ApplyArgsManOptions`, `MemPoolOptions`
-----
Questions for Reviewers:
1. Should we use `std::chrono::seconds` for `CTxMemPool::Options::expiry` and `CTxMemPool::m_expiry` instead of an `int64_t`? Something else? (`std::chrono::hours`?)
2. Should I merge `CTxMemPool::Limits` inside `CTxMemPool::Options`?
ACKs for top commit:
MarcoFalke:
ACK d1684beabe🍜
ryanofsky:
Code review ACK d1684beabe. Just minor cleanups since last review, mostly switching to brace initialization
Tree-SHA512: 2c138e52d69f61c263f1c3648f01c801338a8f576762c815f478ef5148b8b2f51e91ded5c1be915e678c0b14f6cfba894b82afec58d999d39a7bb7c914736e0b
Change getheaders messages so that we wait up to 2 minutes for a response to a
prior getheaders message before issuing a new one.
Also change the handling of the getheaders message sent in response to a block
INV, so that we no longer use the hashstop variable (including the hash stop
will just mean that if our peer's headers chain is longer, then we won't learn
it, so there's no benefit to using hashstop).
Also, now respond to a getheaders during IBD with an empty headers message
(rather than nothing) -- this better conforms to the intent of the new logic
that it's better to not ignore a peer's getheaders message, even if you have
nothing to give. This also avoids a lot of functional tests breaking.
p2p_segwit.py is modified to use this same strategy, as the test logic (of
expecting a getheaders after a block inv) would otherwise be broken.
Also moves the call to happen directly after validation of a headers message
(rather than mixed in with other state updates for the peer), and removes an
incorrect comment in favor of one that explains why headers sync must continue
from the last header a peer has sent.
