diff options
author | John Newbery <john@johnnewbery.com> | 2020-06-15 09:28:56 -0400 |
---|---|---|
committer | John Newbery <john@johnnewbery.com> | 2020-07-11 07:06:20 +0100 |
commit | a49781e56d2bd6a61ec027a09c1db9ee1a4abf2e (patch) | |
tree | 292214604d5f804e38c0cc17858f06f79d4dff5f /src | |
parent | a1d5a428a24afe4f600be29e9d0d3bb4c720e816 (diff) | |
download | bitcoin-a49781e56d2bd6a61ec027a09c1db9ee1a4abf2e.tar.xz |
[net processing] Only call MaybeDiscourageAndDisconnect from SendMessages
`nMisbehavior` is a tally in `CNodeState` that can be incremented from
anywhere. That almost always happens inside a `ProcessMessages()` call
(because we increment the misbehavior score when receiving a bad
messages from a peer), but not always. See, for example, the call to
`MaybePunishNodeForBlock()` inside `BlockChecked()`, which is an
asynchronous callback from the validation interface, executed on the
scheduler thread.
As long as `MaybeDiscourageAndDisconnect()` is called regularly for the
node, then the misbehavior score exceeding the 100 threshold will
eventually result in the peer being punished. It doesn't really matter
where that `MaybeDiscourageAndDisconnect()` happens, but it makes most
sense in `SendMessages()` which is where we do general peer
housekeeping/maintenance.
Therefore, remove the `MaybeDiscourageAndDisconnect()` call in
`ProcessMessages()` and move the `MaybeDiscourageAndDisconnect()` call
in `SendMessages()` to the top of the function. This moves it out of the
cs_main lock scope, so take that lock directly inside
`MaybeDiscourageAndDisconnect()`.
Historic note: `MaybeDiscourageAndDisconnect()` was previously
`SendRejectsAndCheckIfBanned()`, and before that was just sending
rejects. All of those things required cs_main, which is why
`MaybeDiscourageAndDisconnect()` was called after the ping logic.
Diffstat (limited to 'src')
-rw-r--r-- | src/net_processing.cpp | 11 | ||||
-rw-r--r-- | src/net_processing.h | 2 |
2 files changed, 6 insertions, 7 deletions
diff --git a/src/net_processing.cpp b/src/net_processing.cpp index f8b22cd7c8..570cca0c66 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -3559,7 +3559,7 @@ void ProcessMessage( bool PeerLogicValidation::MaybeDiscourageAndDisconnect(CNode& pnode) { - AssertLockHeld(cs_main); + LOCK(cs_main); CNodeState &state = *State(pnode.GetId()); if (state.m_should_discourage) { @@ -3675,9 +3675,6 @@ bool PeerLogicValidation::ProcessMessages(CNode* pfrom, std::atomic<bool>& inter LogPrint(BCLog::NET, "%s(%s, %u bytes): Unknown exception caught\n", __func__, SanitizeString(msg_type), nMessageSize); } - LOCK(cs_main); - MaybeDiscourageAndDisconnect(*pfrom); - return fMoreWork; } @@ -3839,6 +3836,10 @@ bool PeerLogicValidation::SendMessages(CNode* pto) { const Consensus::Params& consensusParams = Params().GetConsensus(); + // We must call MaybeDiscourageAndDisconnect first, to ensure that we'll + // disconnect misbehaving peers even before the version handshake is complete. + if (MaybeDiscourageAndDisconnect(*pto)) return true; + // Don't send anything until the version handshake is complete if (!pto->fSuccessfullyConnected || pto->fDisconnect) return true; @@ -3878,8 +3879,6 @@ bool PeerLogicValidation::SendMessages(CNode* pto) { LOCK(cs_main); - if (MaybeDiscourageAndDisconnect(*pto)) return true; - CNodeState &state = *State(pto->GetId()); // Address refresh broadcast diff --git a/src/net_processing.h b/src/net_processing.h index eadf29e59f..48bcbc1a6c 100644 --- a/src/net_processing.h +++ b/src/net_processing.h @@ -31,7 +31,7 @@ private: ChainstateManager& m_chainman; CTxMemPool& m_mempool; - bool MaybeDiscourageAndDisconnect(CNode& pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main); + bool MaybeDiscourageAndDisconnect(CNode& pnode); public: PeerLogicValidation(CConnman* connman, BanMan* banman, CScheduler& scheduler, ChainstateManager& chainman, CTxMemPool& pool); |