diff options
author | Suhas Daftuar <sdaftuar@gmail.com> | 2022-01-26 18:29:56 -0500 |
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committer | Suhas Daftuar <sdaftuar@gmail.com> | 2022-02-22 11:34:05 -0500 |
commit | ef6dbe6863d92710fd2da7781e5b2aac87578751 (patch) | |
tree | c3e631f9c8a81987feba60d2f68394c6c0c2b672 /src/net_processing.cpp | |
parent | d0bf9bb6a539f151ec92725d20a2b6c22cb095a5 (diff) | |
download | bitcoin-ef6dbe6863d92710fd2da7781e5b2aac87578751.tar.xz |
Respond to getheaders if we have sufficient chainwork
Previously, we would check to see if we were in IBD and ignore getheaders
requests accordingly. However, the IBD criteria -- an optimization mostly
targeted at behavior when we have peers serving us many blocks we need to
download -- is difficult to reason about in edge-case scenarios, such as if the
network were to go a long time without any blocks found and nodes getting
restarted during that time.
To make things simpler to reason about, just use nMinimumChainWork as our
anti-DoS threshold; as long as our chain has that much work, it should be fine
to respond to a peer asking for our headers (and this should allow such a peer
to request blocks from us if needed).
Diffstat (limited to 'src/net_processing.cpp')
-rw-r--r-- | src/net_processing.cpp | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/src/net_processing.cpp b/src/net_processing.cpp index 273cb4fccb..ac6b4654f1 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -3189,9 +3189,23 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type, return; } + if (fImporting || fReindex) { + LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d while importing/reindexing\n", pfrom.GetId()); + return; + } + LOCK(cs_main); - if (m_chainman.ActiveChainstate().IsInitialBlockDownload() && !pfrom.HasPermission(NetPermissionFlags::Download)) { - LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d because node is in initial block download\n", pfrom.GetId()); + + // Note that if we were to be on a chain that forks from the checkpointed + // chain, then serving those headers to a peer that has seen the + // checkpointed chain would cause that peer to disconnect us. Requiring + // that our chainwork exceed nMinimumChainWork is a protection against + // being fed a bogus chain when we started up for the first time and + // getting partitioned off the honest network for serving that chain to + // others. + if (m_chainman.ActiveTip() == nullptr || + (m_chainman.ActiveTip()->nChainWork < nMinimumChainWork && !pfrom.HasPermission(NetPermissionFlags::Download))) { + LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d because active chain has too little work\n", pfrom.GetId()); return; } |