From 5fee401fe14aa6459428a26a82f764db70a6a0b9 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Wed, 4 Jan 2012 23:39:45 +0100 Subject: CAddrMan: stochastic address manager Design goals: * Only keep a limited number of addresses around, so that addr.dat does not grow without bound. * Keep the address tables in-memory, and occasionally write the table to addr.dat. * Make sure no (localized) attacker can fill the entire table with his nodes/addresses. See comments in addrman.h for more detailed information. --- src/addrman.cpp | 506 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 506 insertions(+) create mode 100644 src/addrman.cpp (limited to 'src/addrman.cpp') diff --git a/src/addrman.cpp b/src/addrman.cpp new file mode 100644 index 0000000000..2ef666cf2c --- /dev/null +++ b/src/addrman.cpp @@ -0,0 +1,506 @@ +// Copyright (c) 2012 Pieter Wuille +// Distributed under the MIT/X11 software license, see the accompanying +// file license.txt or http://www.opensource.org/licenses/mit-license.php. + +#include "addrman.h" + +using namespace std; + +int CAddrInfo::GetTriedBucket(const std::vector &nKey) const +{ + CDataStream ss1(SER_GETHASH); + std::vector vchKey = GetKey(); + ss1 << nKey << vchKey; + uint64 hash1 = Hash(ss1.begin(), ss1.end()).Get64(); + + CDataStream ss2(SER_GETHASH); + std::vector vchGroupKey = GetGroup(); + ss2 << nKey << vchGroupKey << (hash1 % ADDRMAN_TRIED_BUCKETS_PER_GROUP); + uint64 hash2 = Hash(ss2.begin(), ss2.end()).Get64(); + return hash2 % ADDRMAN_TRIED_BUCKET_COUNT; +} + +int CAddrInfo::GetNewBucket(const std::vector &nKey, const CNetAddr& src) const +{ + CDataStream ss1(SER_GETHASH); + std::vector vchGroupKey = GetGroup(); + std::vector vchSourceGroupKey = src.GetGroup(); + ss1 << nKey << vchGroupKey << vchSourceGroupKey; + uint64 hash1 = Hash(ss1.begin(), ss1.end()).Get64(); + + CDataStream ss2(SER_GETHASH); + ss2 << nKey << vchSourceGroupKey << (hash1 % ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP); + uint64 hash2 = Hash(ss2.begin(), ss2.end()).Get64(); + return hash2 % ADDRMAN_NEW_BUCKET_COUNT; +} + +bool CAddrInfo::IsTerrible(int64 nNow) const +{ + if (nLastTry && nLastTry >= nNow-60) // never remove things tried the last minute + return false; + + if (nTime > nNow + 10*60) // came in a flying DeLorean + return true; + + if (nTime==0 || nNow-nTime > ADDRMAN_HORIZON_DAYS*86400) // not seen in over a month + return true; + + if (nLastSuccess==0 && nAttempts>=ADDRMAN_RETRIES) // tried three times and never a success + return true; + + if (nNow-nLastSuccess > ADDRMAN_MIN_FAIL_DAYS*86400 && nAttempts>=ADDRMAN_MAX_FAILURES) // 10 successive failures in the last week + return true; + + return false; +} + +double CAddrInfo::GetChance(int64 nNow) const +{ + double fChance = 1.0; + + int64 nSinceLastSeen = nNow - nTime; + int64 nSinceLastTry = nNow - nLastTry; + + if (nSinceLastSeen < 0) nSinceLastSeen = 0; + if (nSinceLastTry < 0) nSinceLastTry = 0; + + fChance *= 600.0 / (600.0 + nSinceLastSeen); + + // deprioritize very recent attempts away + if (nSinceLastTry < 60*10) + fChance *= 0.01; + + // deprioritize 50% after each failed attempt + for (int n=0; n::iterator it = mapAddr.find(addr); + if (it == mapAddr.end()) + return NULL; + if (pnId) + *pnId = (*it).second; + std::map::iterator it2 = mapInfo.find((*it).second); + if (it2 != mapInfo.end()) + return &(*it2).second; + return NULL; +} + +CAddrInfo* CAddrMan::Create(const CAddress &addr, const CNetAddr &addrSource, int *pnId) +{ + int nId = nIdCount++; + mapInfo[nId] = CAddrInfo(addr, addrSource); + mapAddr[addr] = nId; + mapInfo[nId].nRandomPos = vRandom.size(); + vRandom.push_back(nId); + if (pnId) + *pnId = nId; + return &mapInfo[nId]; +} + +void CAddrMan::SwapRandom(int nRndPos1, int nRndPos2) +{ + if (nRndPos1 == nRndPos2) + return; + + int nId1 = vRandom[nRndPos1]; + int nId2 = vRandom[nRndPos2]; + + mapInfo[nId1].nRandomPos = nRndPos2; + mapInfo[nId2].nRandomPos = nRndPos1; + + vRandom[nRndPos1] = nId2; + vRandom[nRndPos2] = nId1; +} + +int CAddrMan::SelectTried(int nKBucket) +{ + std::vector &vTried = vvTried[nKBucket]; + + // random shuffle the first few elements (using the entire list) + // find the least recently tried among them + int64 nOldest = -1; + for (int i=0; i &vNew = vvNew[nUBucket]; + + // first look for deletable items + for (std::set::iterator it = vNew.begin(); it != vNew.end(); it++) + { + CAddrInfo &info = mapInfo[*it]; + if (info.IsTerrible()) + { + if (--info.nRefCount == 0) + { + SwapRandom(info.nRandomPos, vRandom.size()-1); + vRandom.pop_back(); + mapAddr.erase(info); + mapInfo.erase(*it); + nNew--; + } + vNew.erase(it); + return 0; + } + } + + // otherwise, select four randomly, and pick the oldest of those to replace + int n[4] = {GetRandInt(vNew.size()), GetRandInt(vNew.size()), GetRandInt(vNew.size()), GetRandInt(vNew.size())}; + int nI = 0; + int nOldest = -1; + for (std::set::iterator it = vNew.begin(); it != vNew.end(); it++) + { + if (nI == n[0] || nI == n[1] || nI == n[2] || nI == n[3]) + { + if (nOldest == -1 || mapInfo[*it].nTime < mapInfo[nOldest].nTime) + nOldest = *it; + } + nI++; + } + CAddrInfo &info = mapInfo[nOldest]; + if (--info.nRefCount == 0) + { + SwapRandom(info.nRandomPos, vRandom.size()-1); + vRandom.pop_back(); + mapAddr.erase(info); + mapInfo.erase(nOldest); + nNew--; + } + vNew.erase(nOldest); + + return 1; +} + +void CAddrMan::MakeTried(CAddrInfo& info, int nId, int nOrigin) +{ + // remove the entry from all new buckets + for (std::vector >::iterator it = vvNew.begin(); it != vvNew.end(); it++) + { + if ((*it).erase(nId)) + info.nRefCount--; + } + nNew--; + + // what tried bucket to move the entry to + int nKBucket = info.GetTriedBucket(nKey); + std::vector &vTried = vvTried[nKBucket]; + + // first check whether there is place to just add it + if (vTried.size() < ADDRMAN_TRIED_BUCKET_SIZE) + { + vTried.push_back(nId); + nTried++; + info.fInTried = true; + return; + } + + // otherwise, find an item to evict + int nPos = SelectTried(nKBucket); + + // find which new bucket it belongs to + int nUBucket = mapInfo[vTried[nPos]].GetNewBucket(nKey); + std::set &vNew = vvNew[nUBucket]; + + // remove the to-be-replaced tried entry from the tried set + CAddrInfo& infoOld = mapInfo[vTried[nPos]]; + infoOld.fInTried = false; + infoOld.nRefCount = 1; + // do not update nTried, as we are going to move something else there immediately + + // check whether there is place in that one, + if (vNew.size() < ADDRMAN_NEW_BUCKET_SIZE) + { + // if so, move it back there + vNew.insert(vTried[nPos]); + } else { + // otherwise, move it to the new bucket nId came from (there is certainly place there) + vvNew[nOrigin].insert(vTried[nPos]); + } + nNew++; + + vTried[nPos] = nId; + // we just overwrote an entry in vTried; no need to update nTried + info.fInTried = true; + return; +} + +void CAddrMan::Good_(const CService &addr, int64 nTime) +{ +// printf("Good: addr=%s\n", addr.ToString().c_str()); + + int nId; + CAddrInfo *pinfo = Find(addr, &nId); + + // if not found, bail out + if (!pinfo) + return; + + CAddrInfo &info = *pinfo; + + // check whether we are talking about the exact same CService (including same port) + if (info != addr) + return; + + // update info + info.nLastSuccess = nTime; + info.nLastTry = nTime; + info.nTime = nTime; + info.nAttempts = 0; + + // if it is already in the tried set, don't do anything else + if (info.fInTried) + return; + + // find a bucket it is in now + int nRnd = GetRandInt(vvNew.size()); + int nUBucket = -1; + for (int n = 0; n < vvNew.size(); n++) + { + int nB = (n+nRnd) % vvNew.size(); + std::set &vNew = vvNew[nB]; + if (vNew.count(nId)) + { + nUBucket = nB; + break; + } + } + + // if no bucket is found, something bad happened; + // TODO: maybe re-add the node, but for now, just bail out + if (nUBucket == -1) return; + + printf("Moving %s to tried\n", addr.ToString().c_str()); + + // move nId to the tried tables + MakeTried(info, nId, nUBucket); +} + +bool CAddrMan::Add_(const CAddress &addr, const CNetAddr& source, int64 nTimePenalty) +{ + if (!addr.IsRoutable()) + return false; + + bool fNew = false; + int nId; + CAddrInfo *pinfo = Find(addr, &nId); + + if (pinfo) + { + // periodically update nTime + bool fCurrentlyOnline = (GetAdjustedTime() - addr.nTime < 24 * 60 * 60); + int64 nUpdateInterval = (fCurrentlyOnline ? 60 * 60 : 24 * 60 * 60); + if (addr.nTime && (!pinfo->nTime || pinfo->nTime < addr.nTime - nUpdateInterval - nTimePenalty)) + pinfo->nTime = max((int64)0, addr.nTime - nTimePenalty); + + // add services + pinfo->nServices |= addr.nServices; + + // do not update if no new information is present + if (!addr.nTime || pinfo->nTime && addr.nTime <= pinfo->nTime) + return false; + + // do not update if the entry was already in the "tried" table + if (pinfo->fInTried) + return false; + + // do not update if the max reference count is reached + if (pinfo->nRefCount == ADDRMAN_NEW_BUCKETS_PER_ADDRESS) + return false; + + // stochastic test: previous nRefCount == N: 2^N times harder to increase it + int nFactor = 1; + for (int n=0; nnRefCount; n++) + nFactor *= 2; + if (nFactor > 1 && (GetRandInt(nFactor) != 0)) + return false; + } else { + pinfo = Create(addr, source, &nId); + pinfo->nTime = max((int64)0, (int64)pinfo->nTime - nTimePenalty); +// printf("Added %s [nTime=%fhr]\n", pinfo->ToString().c_str(), (GetAdjustedTime() - pinfo->nTime) / 3600.0); + nNew++; + fNew = true; + } + + int nUBucket = pinfo->GetNewBucket(nKey, source); + std::set &vNew = vvNew[nUBucket]; + if (!vNew.count(nId)) + { + pinfo->nRefCount++; + if (vNew.size() == ADDRMAN_NEW_BUCKET_SIZE) + ShrinkNew(nUBucket); + vvNew[nUBucket].insert(nId); + } + return fNew; +} + +void CAddrMan::Attempt_(const CService &addr, int64 nTime) +{ + CAddrInfo *pinfo = Find(addr); + + // if not found, bail out + if (!pinfo) + return; + + CAddrInfo &info = *pinfo; + + // check whether we are talking about the exact same CService (including same port) + if (info != addr) + return; + + // update info + info.nLastTry = nTime; + info.nAttempts++; +} + +CAddress CAddrMan::Select_(int nUnkBias) +{ + if (size() == 0) + return CAddress(); + + double nCorTried = sqrt(nTried) * (100.0 - nUnkBias); + double nCorNew = sqrt(nNew) * nUnkBias; + if ((nCorTried + nCorNew)*GetRandInt(1<<30)/(1<<30) < nCorTried) + { + // use a tried node + double fChanceFactor = 1.0; + while(1) + { + int nKBucket = GetRandInt(vvTried.size()); + std::vector &vTried = vvTried[nKBucket]; + if (vTried.size() == 0) continue; + int nPos = GetRandInt(vTried.size()); + CAddrInfo &info = mapInfo[vTried[nPos]]; + if (GetRandInt(1<<30) < fChanceFactor*info.GetChance()*(1<<30)) + return info; + fChanceFactor *= 1.2; + } + } else { + // use an new node + double fChanceFactor = 1.0; + while(1) + { + int nUBucket = GetRandInt(vvNew.size()); + std::set &vNew = vvNew[nUBucket]; + if (vNew.size() == 0) continue; + int nPos = GetRandInt(vNew.size()); + std::set::iterator it = vNew.begin(); + while (nPos--) + it++; + CAddrInfo &info = mapInfo[*it]; + if (GetRandInt(1<<30) < fChanceFactor*info.GetChance()*(1<<30)) + return info; + fChanceFactor *= 1.2; + } + } +} + +#ifdef DEBUG_ADDRMAN +int CAddrMan::Check_() +{ + std::set setTried; + std::map mapNew; + + if (vRandom.size() != nTried + nNew) return -7; + + for (std::map::iterator it = mapInfo.begin(); it != mapInfo.end(); it++) + { + int n = (*it).first; + CAddrInfo &info = (*it).second; + if (info.fInTried) + { + + if (!info.nLastSuccess) return -1; + if (info.nRefCount) return -2; + setTried.insert(n); + } else { + if (info.nRefCount < 0 || info.nRefCount > ADDRMAN_NEW_BUCKETS_PER_ADDRESS) return -3; + if (!info.nRefCount) return -4; + mapNew[n] = info.nRefCount; + } + if (mapAddr[info] != n) return -5; + if (info.nRandomPos<0 || info.nRandomPos>=vRandom.size() || vRandom[info.nRandomPos] != n) return -14; + if (info.nLastTry < 0) return -6; + if (info.nLastSuccess < 0) return -8; + } + + if (setTried.size() != nTried) return -9; + if (mapNew.size() != nNew) return -10; + + for (int n=0; n &vTried = vvTried[n]; + for (std::vector::iterator it = vTried.begin(); it != vTried.end(); it++) + { + if (!setTried.count(*it)) return -11; + setTried.erase(*it); + } + } + + for (int n=0; n &vNew = vvNew[n]; + for (std::set::iterator it = vNew.begin(); it != vNew.end(); it++) + { + if (!mapNew.count(*it)) return -12; + if (--mapNew[*it] == 0) + mapNew.erase(*it); + } + } + + if (setTried.size()) return -13; + if (mapNew.size()) return -15; + + return 0; +} +#endif + +void CAddrMan::GetAddr_(std::vector &vAddr) +{ + int nNodes = ADDRMAN_GETADDR_MAX_PCT*vRandom.size()/100; + if (nNodes > ADDRMAN_GETADDR_MAX) + nNodes = ADDRMAN_GETADDR_MAX; + + // perform a random shuffle over the first nNodes elements of vRandom (selecting from all) + for (int n = 0; n nUpdateInterval) + info.nTime = nTime; +} -- cgit v1.2.3