That OP_NOP10 is the last executable opcode is a bit of a obscure trivia, and the MAX_OPCODE constant already exists. This merely standardizes use of MAX_OPCODE over OP_NOP10 where it makes sense and is more clear.
Note that the CScheduler thread cant be running at this point,
it has already been stopped with the rest of the init threadgroup.
Thus, just calling any remaining loose callbacks during Shutdown()
is sane.
Check that cached script execution results are only valid for the same
script flags; that script execution checks are returned for non-cached
transactions; and that cached results are only valid for transactions
with the same witness hash.
This removes the possibility for GetCoin/HaveCoin/HaveCoinInCache to return
true while the respective coin is spent. By doing it across all calls, some
extra checks can be eliminated.
coins_tests is modified to call HaveCoin sometimes before and sometimes
after AccessCoin. A further change is needed because the semantics for
GetCoin slightly changed, causing a pruned entry in the parent cache to not
be pulled into the child in FetchCoin.
A few "a->an" and "an->a".
"Shows, if the supplied default SOCKS5 proxy" -> "Shows if the supplied default SOCKS5 proxy". Change made on 3 occurrences.
"without fully understanding the ramification of a command" -> "without fully understanding the ramifications of a command".
Removed duplicate words such as "the the".
In order to prevent mixups, our internal range is never allowed as a resolve
result. This means that no user-provided string will ever be confused with an
internal address.
We currently do two resolves for dns seeds: one for the results, and one to
serve in addrman as the source for those addresses.
There's no requirement that the source hostname resolves to the stored
identifier, only that the mapping is unique. So rather than incurring the
second lookup, combine a private subnet with a hash of the hostname.
The resulting v6 ip is guaranteed not to be publicy routable, and has only a
negligible chance of colliding with a user's internal network (which would be
of no consequence anyway).
This adds a new CuckooCache in validation, caching whether all of a
transaction's scripts were valid with a given set of script flags.
Unlike previous attempts at caching an entire transaction's
validity, which have nearly universally introduced consensus
failures, this only caches the validity of a transaction's
scriptSigs. As these are pure functions of the transaction and
data it commits to, this should be much safer.
This is somewhat duplicative with the sigcache, as entries in the
new cache will also have several entries in the sigcache. However,
the sigcache is kept both as ATMP relies on it and because it
prevents malleability-based DoS attacks on the new higher-level
cache. Instead, the -sigcachesize option is re-used - cutting the
sigcache size in half and using the newly freed memory for the
script execution cache.
Transactions which match the script execution cache never even have
entries in the script check thread's workqueue created.
Note that the cache is indexed only on the script execution flags
and the transaction's witness hash. While this is sufficient to
make the CScriptCheck() calls pure functions, this introduces
dependancies on the mempool calculating things such as the
PrecomputedTransactionData object, filling the CCoinsViewCache, etc
in the exact same way as ConnectBlock. I belive this is a reasonable
assumption, but should be noted carefully.
In a rather naive benchmark (reindex-chainstate up to block 284k
with cuckoocache always returning true for contains(),
-assumevalid=0 and a very large dbcache), this connected blocks
~1.7x faster.
This adds the listening address on which incoming connections were received to the
CNode and CNodeStats structures.
The address is reported in `getpeerinfo`.
This can be useful for distinguishing connections received on different listening ports
(e.g. when using a different listening port for Tor hidden service connections)
or different networks.
This patch makes several related changes:
* Changes the CCoinsView virtual methods (GetCoins, HaveCoins, ...)
to be COutPoint/Coin-based rather than txid/CCoins-based.
* Changes the chainstate db to a new incompatible format that is also
COutPoint/Coin based.
* Implements reconstruction code for hash_serialized_2.
* Adapts the coins_tests unit tests (thanks to Russell Yanofsky).
A side effect of the new CCoinsView model is that we can no longer
use the (unreliable) test for transaction outputs in the UTXO set
to determine whether we already have a particular transaction.
This clarifies a bit more the ways in which the new script execution
cache could break consensus in the future if additional data from
the CCoins object were to be used as a part of script execution.
After this change, any such consensus breaks should be very visible
to reviewers, hopefully ensuring no such changes can be made.
The earlier CTxInUndo class now holds the same information as the Coin
class. Instead of duplicating functionality, replace CTxInUndo with a
serialization adapter for Coin.
Mark Friedenbach