Previously all conflicting transactions were evaluated as a whole to
determine if the feerate was being increased. This meant that low
feerate children pulled the feerate down, potentially allowing a high
transaction with a high feerate to be replaced by one with a lower
feerate.
Replaces transactions already in the mempool if a new transaction seen
with a higher fee, specifically both a higher fee per KB and a higher
absolute fee. Children are evaluateed for replacement as well, using the
mempool package tracking to calculate replaced fees/size. Transactions
can opt-out of transaction replacement by setting nSequence >= maxint-1
on all inputs. (which all wallets do already)
d1c3762 Revert "Revert "Enable policy enforcing GetMedianTimePast as the end point of lock-time constraints"" (Gregory Maxwell)
e4e5334 Restore MedianTimePast for locktime. (Gregory Maxwell)
Previously, the undo weren't being flushed during a reindex because
fKnown was set to true in FindBlockPos. That is the correct behaviour
for block files as they aren't being touched, but undo files are
touched.
This changes the behaviour to always flush when switching to a new file
(even for block files, though that isn't really necessary).
Revert "Revert "Add rules--presently disabled--for using GetMedianTimePast as endpoint for lock-time calculations""
This reverts commit 40cd32e835.
After careful analysis it was determined that the change was, in fact, safe and several people were suffering
momentary confusion about locktime semantics.
This reverts commit 9d55050773.
As noted by Luke-Jr, under some conditions this will accept transactions which are invalid by the network
rules. This happens when the current block time is head of the median time past and a transaction's
locktime is in the middle.
This could be addressed by changing the rule to MAX(this_block_time, MTP+offset) but this solution and
the particular offset used deserve some consideration.
* -maxuploadtarget can be set in MiB
* if <limit> - ( time-left-in-24h-cycle / 600 * MAX_BLOCK_SIZE ) has reach, stop serve blocks older than one week and filtered blocks
* no action if limit has reached, no guarantee that the target will not be surpassed
* add outbound limit informations to rpc getnettotals
The lock-time code currently uses CBlock::nTime as the cutoff point for time based locked transactions. This has the unfortunate outcome of creating a perverse incentive for miners to lie about the time of a block in order to collect more fees by including transactions that by wall clock determination have not yet matured. By using CBlockIndex::GetMedianTimePast from the prior block instead, the self-interested miner no longer gains from generating blocks with fraudulent timestamps. Users can compensate for this change by simply adding an hour (3600 seconds) to their time-based lock times.
If enforced, this would be a soft-fork change. This commit only adds the functionality on an unexecuted code path, without changing the behaviour of Bitcoin Core.
Add a comment that explains why the initial "getheader" requests are
made starting from the block preceding the currently best one.
Thanks to sdaftuar for the explanation!
There is no exact science to setting this parameter, but 5000
(just over 1 US cent at the time of writing) is higher than the
cost to relay a transaction around the network (the new benchmark
due to mempool limiting).
After each transaction which is added to mempool, we first call
Expire() to remove old transactions, then throwing away the
lowest-feerate transactions.
After throwing away transactions by feerate, we set the minimum
relay fee to the maximum fee transaction-and-dependant-set we
removed, plus the default minimum relay fee.
After the next block is received, the minimum relay fee is allowed
to decrease exponentially. Its halflife defaults to 12 hours, but
is decreased to 6 hours if the mempool is smaller than half its
maximum size, and 3 hours if the mempool is smaller than a quarter
its maximum size.
The minimum -maxmempool size is 40*-limitdescendantsize, as it is
easy for an attacker to play games with the cheapest
-limitdescendantsize transactions. -maxmempool defaults to 300MB.
This disables high-priority transaction relay when the min relay
fee adjustment is >0 (ie when the mempool is full). When the relay
fee adjustment drops below the default minimum relay fee / 2 it is
set to 0 (re-enabling priority-based free relay).
To bridge the time until a dynamic method for determining this fee is
merged.
This is especially aimed at the stable releases (0.10, 0.11) because
full mempool limiting, as will be in 0.12, is too invasive and risky to
backport.
Assume that when a wallet transaction has a valid block hash and transaction position
in it, the transaction is actually there. We're already trusting wallet data in a
much more fundamental way anyway.
To prevent backward compatibility issues, a new record is used for storing the
block locator in the wallet. Old wallets will see a wallet file synchronized up
to the genesis block, and rescan automatically.
Associate with each CTxMemPoolEntry all the size/fees of descendant
mempool transactions. Sort mempool by max(feerate of entry, feerate
of descendants). Update statistics on-the-fly as transactions enter
or leave the mempool.
Also add ancestor and descendant limiting, so that transactions can
be rejected if the number or size of unconfirmed ancestors exceeds
a target, or if adding a transaction would cause some other mempool
entry to have too many (or too large) a set of unconfirmed in-
mempool descendants.
GetTransaction needs to lock cs_main until ReadBlockFromDisk completes, the data inside CBlockIndex's can change since pruning. This lock was held by all calls to GetTransaction except rest_tx.
- removes mapBlockIndex find operation
- theoretically allows removing the cs_main lock during zqm notification while introducing a new file position lock
We log the cleanSubVer as part of connect. It is not uniquely more informative
than any of the other data we have about a peer, often less. It's also often
long now as well. There is no need to output it as part of mempoolrej,
AcceptToMemoryPool, or pong entries. Leaving it out makes our log entries
more uniform and consistent.
Lets nodes advertise that they offer bloom filter support explicitly.
The protocol version bump allows SPV nodes to assume that NODE_BLOOM is
set if NODE_NETWORK is set for pre-70011 nodes.
Also adds an option to turn bloom filter support off for nodes which
advertise a version number >= 70011. Nodes attempting to use bloom
filters on such protocol versions are banned, and a later upgade
should drop nodes of an older version which attempt to use bloom
filters.
Much code stolen from Peter Todd.
Implements BIP 111
The main effect is to exit processing for recently-rejected hashes,
in case they are pushed to us without prior advertisement. This
behavior was seen in the wild.
An additional effect is to do early checks for mempool or mapOrphan
existence. No logging or nDoS tracking is needed for failures of
these checks.
