If our tip hasn't updated in a while, that may be because our peers are
not relaying blocks to us that we would consider valid. Allow connection
to an additional outbound peer in that circumstance.
Also, periodically check to see if we are exceeding our target number of
outbound peers, and disconnect the one which has least recently
announced a new block to us (choosing the newest such peer in the case
of tie).
e065249 Add unit test for outbound peer eviction (Suhas Daftuar)
5a6d00c Permit disconnection of outbound peers on bad/slow chains (Suhas Daftuar)
c60fd71 Disconnecting from bad outbound peers in IBD (Suhas Daftuar)
Pull request description:
The first commit will disconnect an outbound peer that serves us a headers chain with insufficient work while we're in IBD.
The second commit introduces a way to disconnect outbound peers whose chains fall out of sync with ours:
For a given outbound peer, we check whether their best known block (which is known from the blocks they announce to us) has at least as much work as our tip. If it doesn't, we set a 20 minute timeout, and if we still haven't heard about a block with as much work as our tip had when we set the timeout, then we send a single getheaders message, and wait 2 more minutes. If after two minutes their best known block has insufficient work, we disconnect that peer.
We protect 4 of our outbound peers (who provide some "good" headers chains, ie a chain with at least as much work as our tip at some point) from being subject to this logic, to prevent excessive network topology changes as a result of this algorithm, while still ensuring that we have a reasonable number of nodes not known to be on bogus chains.
We also don't require our peers to be on the same chain as us, to prevent accidental partitioning of the network in the event of a chain split. Note that if our peers are ever on a more work chain than our tip, then we will download and validate it, and then either reorg to it, or learn of a consensus incompatibility with that peer and disconnect. This PR is designed to protect against peers that are on a less work chain which we may never try to download and validate.
Tree-SHA512: 2e0169a1dd8a7fb95980573ac4a201924bffdd724c19afcab5efcef076fdbe1f2cec7dc5f5d7e0a6327216f56d3828884f73642e00c8534b56ec2bb4c854a656
Currently we have no rotation of outbound peers. If an outbound peer
stops serving us blocks, or is on a consensus-incompatible chain with
less work than our tip (but otherwise valid headers), then we will never
disconnect that peer, even though that peer is using one of our 8
outbound connection slots. Because we rely on our outbound peers to
find an honest node in order to reach consensus, allowing an
incompatible peer to occupy one of those slots is undesirable,
particularly if it is possible for all such slots to be occupied by such
peers.
Protect against this by always checking to see if a peer's best known
block has less work than our tip, and if so, set a 20 minute timeout --
if the peer is still not known to have caught up to a chain with as much
work as ours after 20 minutes, then send a single getheaders message,
wait 2 more minutes, and if a better header hasn't been received by then,
disconnect that peer.
Note:
- we do not require that our peer sync to the same tip as ours, just an
equal or greater work tip. (Doing otherwise would risk partitioning the
network in the event of a chain split, and is also unnecessary.)
- we pick 4 of our outbound peers and do not subject them to this logic,
to be more conservative. We don't wish to permit temporary network
issues (or an attacker) to excessively disrupt network topology.
15f5d3b17 Switch DNSSeed-needed metric to any-automatic-nodes, not services (Matt Corallo)
5ee88b4bd Clarify docs for requirements/handling of addnode/connect nodes (Matt Corallo)
57edc0b0c Rename fAddnode to a more-descriptive "manual_connection" (Matt Corallo)
44407100f Replace relevant services logic with a function suite. (Matt Corallo)
Pull request description:
This was mostly written as a way to clean things up so that the NETWORK_LIMITED PR (#10387) can be simplified a ton, but its also a nice standalone cleanup that will also require a bit of review because it tweaks a lot of stuff across net. The new functions are fine in protocol.h right now since they're straight-forward, but after NETWORK_LIMITED will really want to move elsewhere after @theuni moves the nServices-based selection to addrman from connman.
Adds HasAllRelevantServices and GetRelevantServices, which check
for NETWORK|WITNESS.
This changes the following:
* Removes nRelevantServices from CConnman, disconnecting it a bit
more from protocol-level logic.
* Replaces our sometimes-connect-to-!WITNESS-nodes logic with
simply always requiring WITNESS|NETWORK for outbound non-feeler
connections (feelers still only require NETWORK).
* This has the added benefit of removing nServicesExpected from
CNode - instead letting net_processing's VERSION message
handling simply check HasAllRelevantServices.
* This implies we believe WITNESS nodes to continue to be a
significant majority of nodes on the network, but also because
we cannot sync properly from !WITNESS nodes, it is strange to
continue using our valuable outbound slots on them.
* In order to prevent this change from preventing connection to
-connect= nodes which have !WITNESS, -connect nodes are now
given the "addnode" flag. This also allows outbound connections
to !NODE_NETWORK nodes for -connect nodes (which was already true
of addnodes).
* Has the (somewhat unintended) consequence of changing one of the
eviction metrics from the same
sometimes-connect-to-!WITNESS-nodes metric to requiring
HasRelevantServices.
This should make NODE_NETWORK_LIMITED much simpler to implement.
Tree-SHA512: 90606896c86cc5da14c77843b16674a6a012065e7b583d76d1c47a18215358abefcbab44ff4fab3fadcd39aa9a42d4740c6dc8874a58033bdfc8ad3fb5c649fc
Adds HasAllRelevantServices and GetRelevantServices, which check
for NETWORK|WITNESS.
This changes the following:
* Removes nRelevantServices from CConnman, disconnecting it a bit
more from protocol-level logic.
* Replaces our sometimes-connect-to-!WITNESS-nodes logic with
simply always requiring WITNESS|NETWORK for outbound non-feeler
connections (feelers still only require NETWORK).
* This has the added benefit of removing nServicesExpected from
CNode - instead letting net_processing's VERSION message
handling simply check HasAllRelevantServices.
* This implies we believe WITNESS nodes to continue to be a
significant majority of nodes on the network, but also because
we cannot sync properly from !WITNESS nodes, it is strange to
continue using our valuable outbound slots on them.
* In order to prevent this change from preventing connection to
-connect= nodes which have !WITNESS, -connect nodes are now
given the "addnode" flag. This also allows outbound connections
to !NODE_NETWORK nodes for -connect nodes (which was already true
of addnodes).
* Has the (somewhat unintended) consequence of changing one of the
eviction metrics from the same
sometimes-connect-to-!WITNESS-nodes metric to requiring
HasRelevantServices.
This should make NODE_NETWORK_LIMITED much simpler to implement.
Sending a getheaders message with an empty locator and a stop hash
is a request for a single header by hash. The node will respond with
headers for blocks not in the main chain as well as those in the main
chain. To avoid fingerprinting, the node should, however, ignore
requests for headers on side branches that are too old.
Combine fLimitFree and fOverrideMempoolLimit into a single boolean:
bypass_limits. This is used to indicate that mempool limiting based on feerate
should be bypassed. It is used when readding transactions from a reorg and then
the mempool is trimmed to size after all transactions are added and they can be
evaluated in the context of their descendants. No changes to behavior.
There are a few too many edge-cases here to make this a scripted diff.
The following commits will move a few functions into PeerLogicValidation, where
the local connman instance can be used. This change prepares for that usage.
c00199244 Fix potential null dereferences (MeshCollider)
Pull request description:
Picked up by the static analyzer [Facebook Infer](http://fbinfer.com/) which I was playing around with for another research project. Just adding some asserts before dereferencing potentially null pointers.
Tree-SHA512: 9c01dab2d21bce75c7c7ef867236654ab538318a1fb39f96f09cdd2382a05be1a6b2db0a1169a94168864e82ffeae0686a383db6eba799742bdd89c37ac74397
90d4d89 scripted-diff: Use the C++11 keyword nullptr to denote the pointer literal instead of the macro NULL (practicalswift)
Pull request description:
Since C++11 the macro `NULL` may be:
* an integer literal with value zero, or
* a prvalue of type `std::nullptr_t`
By using the C++11 keyword `nullptr` we are guaranteed a prvalue of type `std::nullptr_t`.
For a more thorough discussion, see "A name for the null pointer: nullptr" (Sutter &
Stroustrup), http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2431.pdf
With this patch applied there are no `NULL` macro usages left in the repo:
```
$ git grep NULL -- "*.cpp" "*.h" | egrep -v '(/univalue/|/secp256k1/|/leveldb/|_NULL|NULLDUMMY|torcontrol.*NULL|NULL cert)' | wc -l
0
```
The road towards `nullptr` (C++11) is split into two PRs:
* `NULL` → `nullptr` is handled in PR #10483 (scripted, this PR)
* `0` → `nullptr` is handled in PR #10645 (manual)
Tree-SHA512: 3c395d66f2ad724a8e6fed74b93634de8bfc0c0eafac94e64e5194c939499fefd6e68f047de3083ad0b4eff37df9a8a3a76349aa17d55eabbd8e0412f140a297
3f8fa7f Make sure to clean up mapBlockSource if we've already seen the block (Cory Fields)
Pull request description:
Otherwise we may leave them dangling.
Credit TheBlueMatt.
Tree-SHA512: 8be77e08ebfc4f5b206d5ee7cfbe87f92c1eb5bc2b412471993658fe210306789aaf0f3d1454c635508a7d8effede2cf5ac144d622b0157b872733d9661d65c3
5a9b508 [trivial] Add end of namespace comments (practicalswift)
Tree-SHA512: 92b0fcae4d1d3f4da9e97569ae84ef2d6e09625a5815cd0e5f0eb6dd2ecba9852fa85c184c5ae9de5117050330ce995e9867b451fa8cd5512169025990541a2b
At startup, we choose one peer to serve us the headers chain, until
our best header is close to caught up. Disconnect this peer if more
than 15 minutes + 1ms/expected_header passes and our best header
is still more than 1 day away from current time.
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.
0f3471f net: make CNode's id private (Cory Fields)
9ff0a51 scripted-diff: net: Use accessor rather than node's id directly (Cory Fields)
e50c33e devtools: add script to verify scriptable changes (Cory Fields)
Tree-SHA512: a0ff50f4e1d38a2b63109b4996546c91b3e02e00d92c0bf04f48792948f78b1f6d9227a15d25c823fd4723a0277fc6a32c2c1287c7abbb7e50fd82ffb0f8d994
vToFetch is never used after declaration. When checked if not empty,
evaluation is always false. Best case scenario this is optimized by the
compiler, worst case it wastes cpu cycles. It should be removed either
way.
