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_processing.cpp | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) (limited to 'src/net_processing.cpp') diff --git a/src/net_processing.cpp b/src/net_processing.cpp index 80e58a6db..eae3e9a2f 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -1019,7 +1019,7 @@ unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans) } /** - * Mark a misbehaving peer to be banned depending upon the value of `-banscore`. + * Increment peer's misbehavior score. If the new value surpasses banscore (specified on startup or by default), mark node to be discouraged, meaning the peer might be disconnected & added to the discouragement filter. */ void Misbehaving(NodeId pnode, int howmuch, const std::string& message) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { @@ -1035,14 +1035,14 @@ void Misbehaving(NodeId pnode, int howmuch, const std::string& message) EXCLUSIV std::string message_prefixed = message.empty() ? "" : (": " + message); if (state->nMisbehavior >= banscore && state->nMisbehavior - howmuch < banscore) { - LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d) BAN THRESHOLD EXCEEDED%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed); + LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d) DISCOURAGE THRESHOLD EXCEEDED%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed); state->fShouldBan = true; } else LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d)%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed); } /** - * Potentially ban a node based on the contents of a BlockValidationState object + * Potentially mark a node discouraged based on the contents of a BlockValidationState object * * @param[in] via_compact_block this bool is passed in because net_processing should * punish peers differently depending on whether the data was provided in a compact @@ -1072,7 +1072,7 @@ static bool MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& s break; } - // Ban outbound (but not inbound) peers if on an invalid chain. + // Discourage outbound (but not inbound) peers if on an invalid chain. // Exempt HB compact block peers and manual connections. if (!via_compact_block && !node_state->m_is_inbound && !node_state->m_is_manual_connection) { Misbehaving(nodeid, 100, message); @@ -1107,7 +1107,7 @@ static bool MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& s } /** - * Potentially ban a node based on the contents of a TxValidationState object + * Potentially disconnect and discourage a node based on the contents of a TxValidationState object * * @return Returns true if the peer was punished (probably disconnected) */ @@ -1339,7 +1339,7 @@ void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew, const CB } /** - * Handle invalid block rejection and consequent peer banning, maintain which + * Handle invalid block rejection and consequent peer discouragement, maintain which * peers announce compact blocks. */ void PeerLogicValidation::BlockChecked(const CBlock& block, const BlockValidationState& state) { @@ -3118,7 +3118,7 @@ void ProcessMessage( // relayed before full validation (see BIP 152), so we don't want to disconnect // the peer if the header turns out to be for an invalid block. // Note that if a peer tries to build on an invalid chain, that - // will be detected and the peer will be banned. + // will be detected and the peer will be disconnected/discouraged. return ProcessHeadersMessage(pfrom, connman, chainman, mempool, {cmpctblock.header}, chainparams, /*via_compact_block=*/true); } @@ -3204,7 +3204,7 @@ void ProcessMessage( // 3. the block is otherwise invalid (eg invalid coinbase, // block is too big, too many legacy sigops, etc). // So if CheckBlock failed, #3 is the only possibility. - // Under BIP 152, we don't DoS-ban unless proof of work is + // Under BIP 152, we don't discourage the peer unless proof of work is // invalid (we don't require all the stateless checks to have // been run). This is handled below, so just treat this as // though the block was successfully read, and rely on the @@ -3576,11 +3576,12 @@ bool PeerLogicValidation::CheckIfBanned(CNode& pnode) else if (pnode.m_manual_connection) LogPrintf("Warning: not punishing manually-connected peer %s!\n", pnode.addr.ToString()); else if (pnode.addr.IsLocal()) { - // Disconnect but don't ban _this_ local node - LogPrintf("Warning: disconnecting but not banning local peer %s!\n", pnode.addr.ToString()); + // Disconnect but don't discourage this local node + LogPrintf("Warning: disconnecting but not discouraging local peer %s!\n", pnode.addr.ToString()); pnode.fDisconnect = true; } else { // Disconnect and ban all nodes sharing the address + LogPrintf("Disconnecting and discouraging peer %s!\n", pnode.addr.ToString()); if (m_banman) { m_banman->Ban(pnode.addr, BanReasonNodeMisbehaving); } -- 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_processing.cpp | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) (limited to 'src/net_processing.cpp') diff --git a/src/net_processing.cpp b/src/net_processing.cpp index eae3e9a2f..717d1453a 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -252,8 +252,8 @@ struct CNodeState { bool fCurrentlyConnected; //! Accumulated misbehaviour score for this peer. int nMisbehavior; - //! Whether this peer should be disconnected and banned (unless whitelisted). - bool fShouldBan; + //! Whether this peer should be disconnected and marked as discouraged (unless whitelisted with noban). + bool m_should_discourage; //! String name of this peer (debugging/logging purposes). const std::string name; //! The best known block we know this peer has announced. @@ -404,7 +404,7 @@ struct CNodeState { { fCurrentlyConnected = false; nMisbehavior = 0; - fShouldBan = false; + m_should_discourage = false; pindexBestKnownBlock = nullptr; hashLastUnknownBlock.SetNull(); pindexLastCommonBlock = nullptr; @@ -1036,7 +1036,7 @@ void Misbehaving(NodeId pnode, int howmuch, const std::string& message) EXCLUSIV if (state->nMisbehavior >= banscore && state->nMisbehavior - howmuch < banscore) { LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d) DISCOURAGE THRESHOLD EXCEEDED%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed); - state->fShouldBan = true; + state->m_should_discourage = true; } else LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d)%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed); } @@ -2476,7 +2476,8 @@ void ProcessMessage( if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60) addr.nTime = nNow - 5 * 24 * 60 * 60; pfrom.AddAddressKnown(addr); - if (banman->IsBanned(addr)) continue; // Do not process banned addresses beyond remembering we received them + if (banman->IsDiscouraged(addr)) continue; // Do not process banned/discouraged addresses beyond remembering we received them + if (banman->IsBanned(addr)) continue; bool fReachable = IsReachable(addr); if (addr.nTime > nSince && !pfrom.fGetAddr && vAddr.size() <= 10 && addr.IsRoutable()) { @@ -3329,7 +3330,7 @@ void ProcessMessage( std::vector vAddr = connman->GetAddresses(); FastRandomContext insecure_rand; for (const CAddress &addr : vAddr) { - if (!banman->IsBanned(addr)) { + if (!banman->IsDiscouraged(addr) && !banman->IsBanned(addr)) { pfrom.PushAddress(addr, insecure_rand); } } @@ -3564,26 +3565,26 @@ void ProcessMessage( return; } -bool PeerLogicValidation::CheckIfBanned(CNode& pnode) +bool PeerLogicValidation::MaybeDiscourageAndDisconnect(CNode& pnode) { AssertLockHeld(cs_main); CNodeState &state = *State(pnode.GetId()); - if (state.fShouldBan) { - state.fShouldBan = false; - if (pnode.HasPermission(PF_NOBAN)) + if (state.m_should_discourage) { + state.m_should_discourage = false; + if (pnode.HasPermission(PF_NOBAN)) { LogPrintf("Warning: not punishing whitelisted peer %s!\n", pnode.addr.ToString()); - else if (pnode.m_manual_connection) + } else if (pnode.m_manual_connection) { LogPrintf("Warning: not punishing manually-connected peer %s!\n", pnode.addr.ToString()); - else if (pnode.addr.IsLocal()) { + } else if (pnode.addr.IsLocal()) { // Disconnect but don't discourage this local node LogPrintf("Warning: disconnecting but not discouraging local peer %s!\n", pnode.addr.ToString()); pnode.fDisconnect = true; } else { - // Disconnect and ban all nodes sharing the address + // Disconnect and discourage all nodes sharing the address LogPrintf("Disconnecting and discouraging peer %s!\n", pnode.addr.ToString()); if (m_banman) { - m_banman->Ban(pnode.addr, BanReasonNodeMisbehaving); + m_banman->Discourage(pnode.addr); } connman->DisconnectNode(pnode.addr); } @@ -3683,7 +3684,7 @@ bool PeerLogicValidation::ProcessMessages(CNode* pfrom, std::atomic& inter } LOCK(cs_main); - CheckIfBanned(*pfrom); + MaybeDiscourageAndDisconnect(*pfrom); return fMoreWork; } @@ -3886,7 +3887,7 @@ bool PeerLogicValidation::SendMessages(CNode* pto) if (!lockMain) return true; - if (CheckIfBanned(*pto)) return true; + if (MaybeDiscourageAndDisconnect(*pto)) return true; CNodeState &state = *State(pto->GetId()); -- cgit v1.2.3