When processing a headers message that looks like a block announcement,
send peer a getheaders if the headers message won't connect.
Apply DoS points after too many consecutive unconnecting headers messages.
This prevents higher order orphans and other junk from
holding positions in the orphan map. Parents delayed
twenty minutes are more are unlikely to ever arrive.
The freed space will improve the orphan matching success rate for
other transactions.
As per meeting 2016-03-31
https://bitcoincore.org/en/meetings/2016/03/31/#bad-chain-alerts
The partition checker was producing huge number of false-positives
and was disabled in 0.12.1 on the understanding it would either be
fixed in 0.13 or removed entirely from master if not.
- BIP9DeploymentInfo struct for static deployment info
- VersionBitsDeploymentInfo: Avoid C++11ism by commenting parameter names
- getblocktemplate: Make sure to set deployments in the version if it is LOCKED_IN
- In this commit, all rules are considered required for clients to support
Previously Bitcoin would send 1/4 of transactions out to all peers
instantly. This causes high overhead because it makes >80% of
INVs size 1. Doing so harms privacy, because it limits the
amount of source obscurity a transaction can receive.
These randomized broadcasts also disobeyed transaction dependencies
and required use of the orphan pool. Because the orphan pool is
so small this leads to poor propagation for dependent transactions.
When the bypass wasn't in effect, transactions were sent in the
order they were received. This avoided creating orphans but
undermines privacy fairly significantly.
This commit:
Eliminates the bypass. The bypass is replaced by halving the
average delay for outbound peers.
Sorts candidate transactions for INV by their topological
depth then by their feerate (then hash); removing the
information leakage and providing priority service to
higher fee transactions.
Limits the amount of transactions sent in a single INV to
7tx/sec (and twice that for outbound); this limits the
harm of low fee transaction floods, gives faster relay
service to higher fee transactions. The 7 sounds lower
than it really is because received advertisements need
not be sent, and because the aggregate rate is multipled
by the number of peers.
Break the circular dependency between main and txdb by:
- Moving `CBlockFileInfo` from `main.h` to `chain.h`. I think this makes
sense, as the other block-file stuff is there too.
- Moving `CDiskTxPos` from `main.h` to `txdb.h`. This type seems
specific to txdb.
- Pass a functor `insertBlockIndex` to `LoadBlockIndexGuts`. This leaves
it up to the caller how to insert block indices.
Currently, we're keeping a timeout for each requested block, starting
from when it is requested, with a correction factor for the number of
blocks in the queue.
That's unnecessarily complicated and inaccurate.
As peers process block requests in order, we can make the timeout for each
block start counting only when all previous ones have been received, and
have a correction based on the number of peers, rather than the total number
of blocks.
The "feefilter" p2p message is used to inform other nodes of your mempool min fee which is the feerate that any new transaction must meet to be accepted to your mempool. This will allow them to filter invs to you according to this feerate.
SequenceLocks functions are used to evaluate sequence lock times or heights per BIP 68.
The majority of this code is copied from maaku in #6312
Further credit: btcdrak, sipa, NicolasDorier
Previously didn't make clear that the ContextualCheckBlock* functions
meant the block headers as context - not the UTXO set itself - and that
ConnectBlock() also did UTXO-related validity checks (in the future we
may split that functionality into a separate UTXO-specific contextual
check block function).
Also, reordered to put validity checks first for better readability.
Also renames whitelistalwaysrelay.
Nodes relay all transactions from whitelisted peers, this
gets in the way of some useful reasons for whitelisting
peers-- for example, bypassing bandwidth limitations.
The purpose of this forced relaying is for specialized gateway
applications where a node is being used as a P2P connection
filter and multiplexer, but where you don't want it getting
in the way of (re-)broadcast.
This change makes it configurable with whitelistforcerelay.
"permit" is currently used to configure transaction filtering, whereas replacement is more to do with the memory pool state than the transaction itself.
Pieter Wuille