From b691f2df5f7d443c0c9ee056ab94aa0fc19566d5 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Mon, 8 Jun 2020 18:46:53 -0700 Subject: Replace automatic bans with discouragement filter This patch improves performance and resource usage around IP addresses that are banned for misbehavior. They're already not actually banned, as connections from them are still allowed, but they are preferred for eviction if the inbound connection slots are full. Stop treating these like manually banned IP ranges, and instead just keep them in a rolling Bloom filter of misbehaving nodes, which isn't persisted to disk or exposed through the ban framework. The effect remains the same: preferred for eviction, avoided for outgoing connections, and not relayed to other peers. Also change the name of this mechanism to better reflect reality; they're not banned, just discouraged. Contains release notes and several interface improvements by John Newbery. --- src/net.cpp | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'src/net.cpp') diff --git a/src/net.cpp b/src/net.cpp index 281232d801..760335e5e5 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -1012,15 +1012,22 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) { int bannedlevel = m_banman ? m_banman->IsBannedLevel(addr) : 0; - // Don't accept connections from banned peers, but if our inbound slots aren't almost full, accept - // if the only banning reason was an automatic misbehavior ban. - if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && bannedlevel > ((nInbound + 1 < nMaxInbound) ? 1 : 0)) + // Don't accept connections from banned peers. + if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && bannedlevel == 2) { LogPrint(BCLog::NET, "connection from %s dropped (banned)\n", addr.ToString()); CloseSocket(hSocket); return; } + // Only accept connections from discouraged peers if our inbound slots aren't (almost) full. + if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && nInbound + 1 >= nMaxInbound && bannedlevel >= 1) + { + LogPrint(BCLog::NET, "connection from %s dropped (discouraged)\n", addr.ToString()); + CloseSocket(hSocket); + return; + } + if (nInbound >= nMaxInbound) { if (!AttemptToEvictConnection()) { -- cgit v1.2.3 From 2ad58381fffb33d611abf900b73d9e6b5a4e35f8 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Wed, 10 Jun 2020 17:11:38 -0700 Subject: Clean up separated ban/discourage interface --- src/net.cpp | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'src/net.cpp') diff --git a/src/net.cpp b/src/net.cpp index 760335e5e5..0233b0fc2f 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -1010,10 +1010,9 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) { // on all platforms. Set it again here just to be sure. SetSocketNoDelay(hSocket); - int bannedlevel = m_banman ? m_banman->IsBannedLevel(addr) : 0; - // Don't accept connections from banned peers. - if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && bannedlevel == 2) + bool banned = m_banman->IsBanned(addr); + if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && banned) { LogPrint(BCLog::NET, "connection from %s dropped (banned)\n", addr.ToString()); CloseSocket(hSocket); @@ -1021,7 +1020,8 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) { } // Only accept connections from discouraged peers if our inbound slots aren't (almost) full. - if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && nInbound + 1 >= nMaxInbound && bannedlevel >= 1) + bool discouraged = m_banman->IsDiscouraged(addr); + if (!NetPermissions::HasFlag(permissionFlags, NetPermissionFlags::PF_NOBAN) && nInbound + 1 >= nMaxInbound && discouraged) { LogPrint(BCLog::NET, "connection from %s dropped (discouraged)\n", addr.ToString()); CloseSocket(hSocket); @@ -1051,7 +1051,7 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) { pnode->m_permissionFlags = permissionFlags; // If this flag is present, the user probably expect that RPC and QT report it as whitelisted (backward compatibility) pnode->m_legacyWhitelisted = legacyWhitelisted; - pnode->m_prefer_evict = bannedlevel > 0; + pnode->m_prefer_evict = discouraged; m_msgproc->InitializeNode(pnode); LogPrint(BCLog::NET, "connection from %s accepted\n", addr.ToString()); @@ -2052,10 +2052,10 @@ void CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFai return; } if (!pszDest) { - if (IsLocal(addrConnect) || - FindNode(static_cast(addrConnect)) || (m_banman && m_banman->IsBanned(addrConnect)) || - FindNode(addrConnect.ToStringIPPort())) + bool banned_or_discouraged = m_banman && (m_banman->IsDiscouraged(addrConnect) || m_banman->IsBanned(addrConnect)); + if (IsLocal(addrConnect) || FindNode(static_cast(addrConnect)) || banned_or_discouraged || FindNode(addrConnect.ToStringIPPort())) { return; + } } else if (FindNode(std::string(pszDest))) return; -- cgit v1.2.3