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author | Wladimir J. van der Laan <laanwj@protonmail.com> | 2020-10-02 16:36:57 +0200 |
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committer | Wladimir J. van der Laan <laanwj@protonmail.com> | 2020-10-02 16:42:38 +0200 |
commit | 597488d37c9c358837616516d88f861f5c25f827 (patch) | |
tree | 8200b3675c5ffde1607e860a984e579b855fd8cb | |
parent | df2129a2349b1877049f250551f49a4592e73765 (diff) | |
parent | d76925478efd35e6fd835370639f2139b28381e4 (diff) | |
download | bitcoin-597488d37c9c358837616516d88f861f5c25f827.tar.xz |
Merge #19871: doc: Clarify scope of eviction protection of outbound block-relay peers
d76925478efd35e6fd835370639f2139b28381e4 [doc] Clarify semantic of peer's m_protect w.r.t to outbound eviction logics (Antoine Riard)
ac71fe936da290adf5a3155fe8db5f78b485f1f1 [doc] Clarify scope of eviction protection of outbound block-relay peers (Antoine Riard)
Pull request description:
Block-relay-only peers were introduced by #15759. According to its
author, it was intented to make them only immune to outbound peer
rotation-based eviction and not from all eviction as modified comment
leans to think of.
Clearly indicate that outbound block-relay peers aren't protected
from eviction by the bad/lagging chain logic.
Fix #19863
ACKs for top commit:
naumenkogs:
ACK d76925478efd35e6fd835370639f2139b28381e4
jonatack:
ACK d76925478efd35e6fd835370639f2139b28381e4
Tree-SHA512: 597fbd62838a6e39276024165b11514cad20a2e9d33cf9202d261cbadcb62b2df427c858e0cb57e585840d4c1d4600104aa53916bb868541f2580e4eed9b4b52
-rw-r--r-- | src/net_processing.cpp | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/src/net_processing.cpp b/src/net_processing.cpp index d3a357fee2..9603d098a4 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -334,10 +334,17 @@ struct CNodeState { */ bool fSupportsDesiredCmpctVersion; - /** State used to enforce CHAIN_SYNC_TIMEOUT - * Only in effect for outbound, non-manual, full-relay connections, with - * m_protect == false - * Algorithm: if a peer's best known block has less work than our tip, + /** State used to enforce CHAIN_SYNC_TIMEOUT and EXTRA_PEER_CHECK_INTERVAL logic. + * + * Both are only in effect for outbound, non-manual, non-protected connections. + * Any peer protected (m_protect = true) is not chosen for eviction. A peer is + * marked as protected if all of these are true: + * - its connection type is IsBlockOnlyConn() == false + * - it gave us a valid connecting header + * - we haven't reached MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT yet + * - it has a better chain than we have + * + * CHAIN_SYNC_TIMEOUT: if a peer's best known block has less work than our tip, * set a timeout CHAIN_SYNC_TIMEOUT seconds in the future: * - If at timeout their best known block now has more work than our tip * when the timeout was set, then either reset the timeout or clear it @@ -347,6 +354,9 @@ struct CNodeState { * and set a shorter timeout, HEADERS_RESPONSE_TIME seconds in future. * If their best known block is still behind when that new timeout is * reached, disconnect. + * + * EXTRA_PEER_CHECK_INTERVAL: after each interval, if we have too many outbound peers, + * drop the outbound one that least recently announced us a new block. */ struct ChainSyncTimeoutState { //! A timeout used for checking whether our peer has sufficiently synced @@ -2018,11 +2028,12 @@ void PeerManager::ProcessHeadersMessage(CNode& pfrom, const std::vector<CBlockHe } } + // If this is an outbound full-relay peer, check to see if we should protect + // it from the bad/lagging chain logic. + // Note that outbound block-relay peers are excluded from this protection, and + // thus always subject to eviction under the bad/lagging chain logic. + // See ChainSyncTimeoutState. if (!pfrom.fDisconnect && pfrom.IsFullOutboundConn() && nodestate->pindexBestKnownBlock != nullptr) { - // If this is an outbound full-relay peer, check to see if we should protect - // it from the bad/lagging chain logic. - // Note that block-relay-only peers are already implicitly protected, so we - // only consider setting m_protect for the full-relay peers. if (g_outbound_peers_with_protect_from_disconnect < MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT && nodestate->pindexBestKnownBlock->nChainWork >= ::ChainActive().Tip()->nChainWork && !nodestate->m_chain_sync.m_protect) { LogPrint(BCLog::NET, "Protecting outbound peer=%d from eviction\n", pfrom.GetId()); nodestate->m_chain_sync.m_protect = true; |