GlcoinCore/elements
1
0
Fork 0
mirror of https://github.com/ElementsProject/elements.git synced 2026-08-14 12:43:40 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Merge 69a13eb246 into merged_master (Bitcoin PR #19670)

Browse source
This commit is contained in:
Andrew Poelstra 2020-11-28 22:08:22 +00:00
commit dfd4a46a05
1 changed files with 36 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

38
src/net.cpp
View file

@ -816,6 +816,7 @@ struct NodeEvictionCandidate
CAddress addr;
uint64_t nKeyedNetGroup;
bool prefer_evict;
bool m_is_local;
};
static bool ReverseCompareNodeMinPingTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b)
@ -828,6 +829,12 @@ static bool ReverseCompareNodeTimeConnected(const NodeEvictionCandidate &a, cons
return a.nTimeConnected > b.nTimeConnected;
}
static bool CompareLocalHostTimeConnected(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b)
{
if (a.m_is_local != b.m_is_local) return b.m_is_local;
return a.nTimeConnected > b.nTimeConnected;
}
static bool CompareNetGroupKeyed(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b) {
return a.nKeyedNetGroup < b.nKeyedNetGroup;
}
@ -849,6 +856,14 @@ static bool CompareNodeTXTime(const NodeEvictionCandidate &a, const NodeEviction
return a.nTimeConnected > b.nTimeConnected;
}
// Pick out the potential block-relay only peers, and sort them by last block time.
static bool CompareNodeBlockRelayOnlyTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b)
{
if (a.fRelayTxes != b.fRelayTxes) return a.fRelayTxes;
if (a.nLastBlockTime != b.nLastBlockTime) return a.nLastBlockTime < b.nLastBlockTime;
if (a.fRelevantServices != b.fRelevantServices) return b.fRelevantServices;
return a.nTimeConnected > b.nTimeConnected;
}
//! Sort an array by the specified comparator, then erase the last K elements.
template<typename T, typename Comparator>
@ -891,7 +906,7 @@ bool CConnman::AttemptToEvictConnection()
node->nLastBlockTime, node->nLastTXTime,
HasAllDesirableServiceFlags(node->nServices),
peer_relay_txes, peer_filter_not_null, node->addr, node->nKeyedNetGroup,
node->m_prefer_evict};
node->m_prefer_evict, node->addr.IsLocal()};
vEvictionCandidates.push_back(candidate);
}
}
@ -907,12 +922,31 @@ bool CConnman::AttemptToEvictConnection()
// Protect 4 nodes that most recently sent us novel transactions accepted into our mempool.
// An attacker cannot manipulate this metric without performing useful work.
EraseLastKElements(vEvictionCandidates, CompareNodeTXTime, 4);
// Protect up to 8 non-tx-relay peers that have sent us novel blocks.
std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), CompareNodeBlockRelayOnlyTime);
size_t erase_size = std::min(size_t(8), vEvictionCandidates.size());
vEvictionCandidates.erase(std::remove_if(vEvictionCandidates.end() - erase_size, vEvictionCandidates.end(), [](NodeEvictionCandidate const &n) { return !n.fRelayTxes && n.fRelevantServices; }), vEvictionCandidates.end());
// Protect 4 nodes that most recently sent us novel blocks.
// An attacker cannot manipulate this metric without performing useful work.
EraseLastKElements(vEvictionCandidates, CompareNodeBlockTime, 4);
// Protect the half of the remaining nodes which have been connected the longest.
// This replicates the non-eviction implicit behavior, and precludes attacks that start later.
EraseLastKElements(vEvictionCandidates, ReverseCompareNodeTimeConnected, vEvictionCandidates.size() / 2);
// Reserve half of these protected spots for localhost peers, even if
// they're not longest-uptime overall. This helps protect tor peers, which
// tend to be otherwise disadvantaged under our eviction criteria.
size_t initial_size = vEvictionCandidates.size();
size_t total_protect_size = initial_size / 2;
// Pick out up to 1/4 peers that are localhost, sorted by longest uptime.
std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), CompareLocalHostTimeConnected);
size_t local_erase_size = total_protect_size / 2;
vEvictionCandidates.erase(std::remove_if(vEvictionCandidates.end() - local_erase_size, vEvictionCandidates.end(), [](NodeEvictionCandidate const &n) { return n.m_is_local; }), vEvictionCandidates.end());
// Calculate how many we removed, and update our total number of peers that
// we want to protect based on uptime accordingly.
total_protect_size -= initial_size - vEvictionCandidates.size();
EraseLastKElements(vEvictionCandidates, ReverseCompareNodeTimeConnected, total_protect_size);
if (vEvictionCandidates.empty()) return false;