From 5400ef6bcb9d243b2b21697775aa6491115420f3 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Wed, 8 Apr 2015 11:20:00 -0700 Subject: [PATCH] Replace trickle nodes with per-node/message Poisson delays We used to have a trickle node, a node which was chosen in each iteration of the send loop that was privileged and allowed to send out queued up non-time critical messages. Since the removal of the fixed sleeps in the network code, this resulted in fast and attackable treatment of such broadcasts. This pull request changes the 3 remaining trickle use cases by random delays: * Local address broadcast (while also removing the the wiping of the seen filter) * Address relay * Inv relay (for transactions; blocks are always relayed immediately) The code is based on older commits by Patrick Strateman. --- src/main.cpp | 34 ++++++++++++++-------------------- src/main.h | 11 +++++++++-- src/net.cpp | 16 ++++++++++------ src/net.h | 8 +++++++- src/test/DoS_tests.cpp | 14 +++++++------- 5 files changed, 47 insertions(+), 36 deletions(-) diff --git a/src/main.cpp b/src/main.cpp index d2e736d42..41fc0b809 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -5326,7 +5326,7 @@ bool ProcessMessages(CNode* pfrom) } -bool SendMessages(CNode* pto, bool fSendTrickle) +bool SendMessages(CNode* pto) { const Consensus::Params& consensusParams = Params().GetConsensus(); { @@ -5368,28 +5368,17 @@ bool SendMessages(CNode* pto, bool fSendTrickle) return true; // Address refresh broadcast - static int64_t nLastRebroadcast; - if (!IsInitialBlockDownload() && (GetTime() - nLastRebroadcast > 24 * 60 * 60)) - { - LOCK(cs_vNodes); - BOOST_FOREACH(CNode* pnode, vNodes) - { - // Periodically clear addrKnown to allow refresh broadcasts - if (nLastRebroadcast) - pnode->addrKnown.reset(); - - // Rebroadcast our address - AdvertizeLocal(pnode); - } - if (!vNodes.empty()) - nLastRebroadcast = GetTime(); + int64_t nNow = GetTimeMicros(); + if (!IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) { + AdvertizeLocal(pto); + pto->nNextLocalAddrSend = PoissonNextSend(nNow, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL); } // // Message: addr // - if (fSendTrickle) - { + if (pto->nNextAddrSend < nNow) { + pto->nNextAddrSend = PoissonNextSend(nNow, AVG_ADDRESS_BROADCAST_INTERVAL); vector vAddr; vAddr.reserve(pto->vAddrToSend.size()); BOOST_FOREACH(const CAddress& addr, pto->vAddrToSend) @@ -5563,8 +5552,13 @@ bool SendMessages(CNode* pto, bool fSendTrickle) vector vInv; vector vInvWait; { + bool fSendTrickle = pto->fWhitelisted; + if (pto->nNextInvSend < nNow) { + fSendTrickle = true; + pto->nNextInvSend = PoissonNextSend(nNow, AVG_INVENTORY_BROADCAST_INTERVAL); + } LOCK(pto->cs_inventory); - vInv.reserve(pto->vInventoryToSend.size()); + vInv.reserve(std::min(1000, pto->vInventoryToSend.size())); vInvWait.reserve(pto->vInventoryToSend.size()); BOOST_FOREACH(const CInv& inv, pto->vInventoryToSend) { @@ -5604,7 +5598,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle) pto->PushMessage(NetMsgType::INV, vInv); // Detect whether we're stalling - int64_t nNow = GetTimeMicros(); + nNow = GetTimeMicros(); if (!pto->fDisconnect && state.nStallingSince && state.nStallingSince < nNow - 1000000 * BLOCK_STALLING_TIMEOUT) { // Stalling only triggers when the block download window cannot move. During normal steady state, // the download window should be much larger than the to-be-downloaded set of blocks, so disconnection diff --git a/src/main.h b/src/main.h index 19623f4d9..25a006387 100644 --- a/src/main.h +++ b/src/main.h @@ -87,6 +87,14 @@ static const unsigned int DATABASE_WRITE_INTERVAL = 60 * 60; static const unsigned int DATABASE_FLUSH_INTERVAL = 24 * 60 * 60; /** Maximum length of reject messages. */ static const unsigned int MAX_REJECT_MESSAGE_LENGTH = 111; +/** Average delay between local address broadcasts in seconds. */ +static const unsigned int AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL = 24 * 24 * 60; +/** Average delay between peer address broadcasts in seconds. */ +static const unsigned int AVG_ADDRESS_BROADCAST_INTERVAL = 30; +/** Average delay between trickled inventory broadcasts in seconds. + * Blocks, whitelisted receivers, and a random 25% of transactions bypass this. */ +static const unsigned int AVG_INVENTORY_BROADCAST_INTERVAL = 5; + static const unsigned int DEFAULT_LIMITFREERELAY = 15; static const bool DEFAULT_RELAYPRIORITY = true; @@ -197,9 +205,8 @@ bool ProcessMessages(CNode* pfrom); * Send queued protocol messages to be sent to a give node. * * @param[in] pto The node which we are sending messages to. - * @param[in] fSendTrickle When true send the trickled data, otherwise trickle the data until true. */ -bool SendMessages(CNode* pto, bool fSendTrickle); +bool SendMessages(CNode* pto); /** Run an instance of the script checking thread */ void ThreadScriptCheck(); /** Try to detect Partition (network isolation) attacks against us */ diff --git a/src/net.cpp b/src/net.cpp index c5e7ece79..e0d96a2dc 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -36,6 +36,8 @@ #include #include +#include + // Dump addresses to peers.dat every 15 minutes (900s) #define DUMP_ADDRESSES_INTERVAL 900 @@ -1733,11 +1735,6 @@ void ThreadMessageHandler() } } - // Poll the connected nodes for messages - CNode* pnodeTrickle = NULL; - if (!vNodesCopy.empty()) - pnodeTrickle = vNodesCopy[GetRand(vNodesCopy.size())]; - bool fSleep = true; BOOST_FOREACH(CNode* pnode, vNodesCopy) @@ -1768,7 +1765,7 @@ void ThreadMessageHandler() { TRY_LOCK(pnode->cs_vSend, lockSend); if (lockSend) - g_signals.SendMessages(pnode, pnode == pnodeTrickle || pnode->fWhitelisted); + g_signals.SendMessages(pnode); } boost::this_thread::interruption_point(); } @@ -2384,6 +2381,9 @@ CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNa nStartingHeight = -1; filterInventoryKnown.reset(); fGetAddr = false; + nNextLocalAddrSend = 0; + nNextAddrSend = 0; + nNextInvSend = 0; fRelayTxes = false; pfilter = new CBloomFilter(); nPingNonceSent = 0; @@ -2634,3 +2634,7 @@ void DumpBanlist() LogPrint("net", "Flushed %d banned node ips/subnets to banlist.dat %dms\n", banmap.size(), GetTimeMillis() - nStart); } + +int64_t PoissonNextSend(int64_t nNow, int average_interval_seconds) { + return nNow + (int64_t)(log1p(GetRand(1ULL << 48) * -0.0000000000000035527136788 /* -1/2^48 */) * average_interval_seconds * -1000000.0 + 0.5); +} diff --git a/src/net.h b/src/net.h index 3ed438605..bc64571ae 100644 --- a/src/net.h +++ b/src/net.h @@ -113,7 +113,7 @@ struct CNodeSignals { boost::signals2::signal GetHeight; boost::signals2::signal ProcessMessages; - boost::signals2::signal SendMessages; + boost::signals2::signal SendMessages; boost::signals2::signal InitializeNode; boost::signals2::signal FinalizeNode; }; @@ -391,6 +391,8 @@ public: CRollingBloomFilter addrKnown; bool fGetAddr; std::set setKnown; + int64_t nNextAddrSend; + int64_t nNextLocalAddrSend; // inventory based relay CRollingBloomFilter filterInventoryKnown; @@ -398,6 +400,7 @@ public: CCriticalSection cs_inventory; std::set setAskFor; std::multimap mapAskFor; + int64_t nNextInvSend; // Used for headers announcements - unfiltered blocks to relay // Also protected by cs_inventory std::vector vBlockHashesToAnnounce; @@ -791,4 +794,7 @@ public: void DumpBanlist(); +/** Return a timestamp in the future (in microseconds) for exponentially distributed events. */ +int64_t PoissonNextSend(int64_t nNow, int average_interval_seconds); + #endif // BITCOIN_NET_H diff --git a/src/test/DoS_tests.cpp b/src/test/DoS_tests.cpp index da296a046..51d296502 100644 --- a/src/test/DoS_tests.cpp +++ b/src/test/DoS_tests.cpp @@ -49,7 +49,7 @@ BOOST_AUTO_TEST_CASE(DoS_banning) CNode dummyNode1(INVALID_SOCKET, addr1, "", true); dummyNode1.nVersion = 1; Misbehaving(dummyNode1.GetId(), 100); // Should get banned - SendMessages(&dummyNode1, false); + SendMessages(&dummyNode1); BOOST_CHECK(CNode::IsBanned(addr1)); BOOST_CHECK(!CNode::IsBanned(ip(0xa0b0c001|0x0000ff00))); // Different IP, not banned @@ -57,11 +57,11 @@ BOOST_AUTO_TEST_CASE(DoS_banning) CNode dummyNode2(INVALID_SOCKET, addr2, "", true); dummyNode2.nVersion = 1; Misbehaving(dummyNode2.GetId(), 50); - SendMessages(&dummyNode2, false); + SendMessages(&dummyNode2); BOOST_CHECK(!CNode::IsBanned(addr2)); // 2 not banned yet... BOOST_CHECK(CNode::IsBanned(addr1)); // ... but 1 still should be Misbehaving(dummyNode2.GetId(), 50); - SendMessages(&dummyNode2, false); + SendMessages(&dummyNode2); BOOST_CHECK(CNode::IsBanned(addr2)); } @@ -73,13 +73,13 @@ BOOST_AUTO_TEST_CASE(DoS_banscore) CNode dummyNode1(INVALID_SOCKET, addr1, "", true); dummyNode1.nVersion = 1; Misbehaving(dummyNode1.GetId(), 100); - SendMessages(&dummyNode1, false); + SendMessages(&dummyNode1); BOOST_CHECK(!CNode::IsBanned(addr1)); Misbehaving(dummyNode1.GetId(), 10); - SendMessages(&dummyNode1, false); + SendMessages(&dummyNode1); BOOST_CHECK(!CNode::IsBanned(addr1)); Misbehaving(dummyNode1.GetId(), 1); - SendMessages(&dummyNode1, false); + SendMessages(&dummyNode1); BOOST_CHECK(CNode::IsBanned(addr1)); mapArgs.erase("-banscore"); } @@ -95,7 +95,7 @@ BOOST_AUTO_TEST_CASE(DoS_bantime) dummyNode.nVersion = 1; Misbehaving(dummyNode.GetId(), 100); - SendMessages(&dummyNode, false); + SendMessages(&dummyNode); BOOST_CHECK(CNode::IsBanned(addr)); SetMockTime(nStartTime+60*60);