This adds a new CValidationInterface subclass, defined in main.h,
to receive notifications of UpdatedBlockTip and use that to push
blocks to peers, instead of doing it directly from
ActivateBestChain.
In anticipation of making all the callbacks out of block processing
flow through it. Note that vHashes will always have something in it
since pindexFork != pindexNewTip.
This fixes a bug where we might (in exceedingly rare circumstances)
accidentally ban a node for sending us the first (potentially few)
segwit blocks in non-segwit mode.
75ead758 turned these into crashes in the event of a handshake failure, most
notably when a peer does not offer the expected services.
There are likely other cases that these assertions will find as well.
In principle, the checksums of P2P packets are simply 4-byte blobs which
are the first four bytes of SHA256(SHA256(payload)).
Currently they are handled as little-endian 32-bit integers half of the
time, as blobs the other half, sometimes copying the one to the other,
resulting in somewhat confused code.
This PR changes the handling to be consistent both at packet creation
and receiving, making it (I think) easier to understand.
An example of where this might be useful is allowing a node to connect blocksonly during IBD but then becoming a full-node once caught up with the latest block. This might also even want to be the default behaviour since during IBD most TXs appear to be orphans, and are routinely dropped (for example when a node disconnects). Therefore, this can waste a lot of bandwidth.
Additionally, another pull could be written to stop relaying of TXs to nodes that are clearly far behind the latest block and are running a node that doesn't store many orphan TXs, such as recent versions of Bitcoin Core.
CConnman then passes the current best height into CNode at creation time.
This way CConnman/CNode have no dependency on main for height, and the signals
only move in one direction.
This also helps to prevent identity leakage a tiny bit. Before this change, an
attacker could theoretically make 2 connections on different interfaces. They
would connect fully on one, and only establish the initial connection on the
other. Once they receive a new block, they would relay it to your first
connection, and immediately commence the version handshake on the second. Since
the new block height is reflected immediately, they could attempt to learn
whether the two connections were correlated.
This is, of course, incredibly unlikely to work due to the small timings
involved and receipt from other senders. But it doesn't hurt to lock-in
nBestHeight at the time of connection, rather than letting the remote choose
the time.
This behavior seems to have been quite racy and broken.
Move nLocalHostNonce into CNode, and check received nonces against all
non-fully-connected nodes. If there's a match, assume we've connected
to ourself.
35fe039 Rename to PrecomputedTransactionData (Pieter Wuille)
ab48c5e Unit test for sighash caching (Nicolas DORIER)
d2c5d04 Precompute sighashes (Pieter Wuille)
We should learn about new peers via address messages.
An inbound peer connecting to us tells us nothing about
its ability to accept incoming connections from us, so
we shouldn't assume that we can connect to it based on
this.
The vast majority of nodes on the network do not accept
incoming connections, adding them will only slow down
the process of making a successful connection in the
future.
Nodes which have configured themselves to not announce would prefer we
not violate their privacy by announcing them in GETADDR responses.
Tests if addresses are online or offline by briefly connecting to them. These short lived connections are referred to as feeler connections. Feeler connections are designed to increase the number of fresh online addresses in tried by selecting and connecting to addresses in new. One feeler connection is attempted on average once every two minutes.
This change was suggested as Countermeasure 4 in
Eclipse Attacks on Bitcoin’s Peer-to-Peer Network, Ethan Heilman,
Alison Kendler, Aviv Zohar, Sharon Goldberg. ePrint Archive Report
2015/263. March 2015.
9d4eb9a Do diskspace check before import thread is started (Pieter Wuille)
aa59f2e Add extra message to avoid a long 'Loading banlist' (Pieter Wuille)
0fd2a33 Use a signal to continue init after genesis activation (Pieter Wuille)
a5072a7 util: Remove zero-argument versions of LogPrint and error (Wladimir J. van der Laan)
695041e util: Update tinyformat (Wladimir J. van der Laan)
c59c434 qa: Add test for standardness of segwit v0 outputs (Suhas Daftuar)
1ffaff2 Make witness v0 outputs non-standard before segwit activation (Johnson Lau)
46c9620 Test that unnecessary witnesses can't be used for mempool DoS (Suhas Daftuar)
bb66a11 Fix DoS vulnerability in mempool acceptance (Suhas Daftuar)
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.
Moves the IsStandard check to happen after the premature-witness check,
so that adding a witness to a transaction can't prevent mempool acceptance.
Note that this doesn't address the broader category of potential mempool DoS
issues that affect transactions after segwit activation.
Changes in tinyformat, recently imported from upstream have made the
zero-argument versions of formatting functions unnecessary. Remove them.
This is a slight semantic change: `%` characters in the zero-argument
call are now regarded and need to be escaped. As for as I know, the only
use of this is in `main.cpp`.
48efec8 Fix some minor compact block issues that came up in review (Matt Corallo)
ccd06b9 Elaborate bucket size math (Pieter Wuille)
0d4cb48 Use vTxHashes to optimize InitData significantly (Matt Corallo)
8119026 Provide a flat list of txid/terators to txn in CTxMemPool (Matt Corallo)
678ee97 Add BIP 152 to implemented BIPs list (Matt Corallo)
56ba516 Add reconstruction debug logging (Matt Corallo)
2f34a2e Get our "best three" peers to announce blocks using cmpctblocks (Matt Corallo)
927f8ee Add ability to fetch CNode by NodeId (Matt Corallo)
d25cd3e Add receiver-side protocol implementation for CMPCTBLOCK stuff (Matt Corallo)
9c837d5 Add sender-side protocol implementation for CMPCTBLOCK stuff (Matt Corallo)
00c4078 Add protocol messages for short-ids blocks (Matt Corallo)
e3b2222 Add some blockencodings tests (Matt Corallo)
f4f8f14 Add TestMemPoolEntryHelper::FromTx version for CTransaction (Matt Corallo)
85ad31e Add partial-block block encodings API (Matt Corallo)
5249dac Add COMPACTSIZE wrapper similar to VARINT for serialization (Matt Corallo)
cbda71c Move context-required checks from CheckBlockHeader to Contextual... (Matt Corallo)
7c29ec9 If AcceptBlockHeader returns true, pindex will be set. (Matt Corallo)
96806c3 Stop trimming when mapTx is empty (Pieter Wuille)
