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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.
This commit is contained in:
Pieter Wuille
506
src/addrman.cpp
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506
src/addrman.cpp
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@@ -0,0 +1,506 @@
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// Copyright (c) 2012 Pieter Wuille
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// Distributed under the MIT/X11 software license, see the accompanying
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// file license.txt or http://www.opensource.org/licenses/mit-license.php.
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#include "addrman.h"
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using namespace std;
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int CAddrInfo::GetTriedBucket(const std::vector<unsigned char> &nKey) const
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{
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CDataStream ss1(SER_GETHASH);
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std::vector<unsigned char> vchKey = GetKey();
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ss1 << nKey << vchKey;
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uint64 hash1 = Hash(ss1.begin(), ss1.end()).Get64();
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CDataStream ss2(SER_GETHASH);
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std::vector<unsigned char> vchGroupKey = GetGroup();
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ss2 << nKey << vchGroupKey << (hash1 % ADDRMAN_TRIED_BUCKETS_PER_GROUP);
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uint64 hash2 = Hash(ss2.begin(), ss2.end()).Get64();
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return hash2 % ADDRMAN_TRIED_BUCKET_COUNT;
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}
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int CAddrInfo::GetNewBucket(const std::vector<unsigned char> &nKey, const CNetAddr& src) const
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{
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CDataStream ss1(SER_GETHASH);
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std::vector<unsigned char> vchGroupKey = GetGroup();
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std::vector<unsigned char> vchSourceGroupKey = src.GetGroup();
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ss1 << nKey << vchGroupKey << vchSourceGroupKey;
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uint64 hash1 = Hash(ss1.begin(), ss1.end()).Get64();
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CDataStream ss2(SER_GETHASH);
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ss2 << nKey << vchSourceGroupKey << (hash1 % ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP);
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uint64 hash2 = Hash(ss2.begin(), ss2.end()).Get64();
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return hash2 % ADDRMAN_NEW_BUCKET_COUNT;
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}
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bool CAddrInfo::IsTerrible(int64 nNow) const
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{
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if (nLastTry && nLastTry >= nNow-60) // never remove things tried the last minute
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return false;
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if (nTime > nNow + 10*60) // came in a flying DeLorean
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return true;
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if (nTime==0 || nNow-nTime > ADDRMAN_HORIZON_DAYS*86400) // not seen in over a month
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return true;
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if (nLastSuccess==0 && nAttempts>=ADDRMAN_RETRIES) // tried three times and never a success
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return true;
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if (nNow-nLastSuccess > ADDRMAN_MIN_FAIL_DAYS*86400 && nAttempts>=ADDRMAN_MAX_FAILURES) // 10 successive failures in the last week
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return true;
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return false;
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}
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double CAddrInfo::GetChance(int64 nNow) const
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{
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double fChance = 1.0;
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int64 nSinceLastSeen = nNow - nTime;
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int64 nSinceLastTry = nNow - nLastTry;
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if (nSinceLastSeen < 0) nSinceLastSeen = 0;
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if (nSinceLastTry < 0) nSinceLastTry = 0;
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fChance *= 600.0 / (600.0 + nSinceLastSeen);
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// deprioritize very recent attempts away
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if (nSinceLastTry < 60*10)
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fChance *= 0.01;
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// deprioritize 50% after each failed attempt
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for (int n=0; n<nAttempts; n++)
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fChance /= 1.5;
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return fChance;
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}
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CAddrInfo* CAddrMan::Find(const CNetAddr& addr, int *pnId)
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{
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std::map<CNetAddr, int>::iterator it = mapAddr.find(addr);
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if (it == mapAddr.end())
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return NULL;
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if (pnId)
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*pnId = (*it).second;
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std::map<int, CAddrInfo>::iterator it2 = mapInfo.find((*it).second);
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if (it2 != mapInfo.end())
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return &(*it2).second;
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return NULL;
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}
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CAddrInfo* CAddrMan::Create(const CAddress &addr, const CNetAddr &addrSource, int *pnId)
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{
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int nId = nIdCount++;
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mapInfo[nId] = CAddrInfo(addr, addrSource);
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mapAddr[addr] = nId;
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mapInfo[nId].nRandomPos = vRandom.size();
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vRandom.push_back(nId);
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if (pnId)
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*pnId = nId;
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return &mapInfo[nId];
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}
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void CAddrMan::SwapRandom(int nRndPos1, int nRndPos2)
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{
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if (nRndPos1 == nRndPos2)
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return;
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int nId1 = vRandom[nRndPos1];
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int nId2 = vRandom[nRndPos2];
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mapInfo[nId1].nRandomPos = nRndPos2;
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mapInfo[nId2].nRandomPos = nRndPos1;
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vRandom[nRndPos1] = nId2;
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vRandom[nRndPos2] = nId1;
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}
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int CAddrMan::SelectTried(int nKBucket)
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{
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std::vector<int> &vTried = vvTried[nKBucket];
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// random shuffle the first few elements (using the entire list)
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// find the least recently tried among them
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int64 nOldest = -1;
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for (int i=0; i<ADDRMAN_TRIED_ENTRIES_INSPECT_ON_EVICT && i<vTried.size(); i++)
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{
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int nPos = GetRandInt(vTried.size() - i) + i;
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int nTemp = vTried[nPos];
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vTried[nPos] = vTried[i];
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vTried[i] = nTemp;
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if (nOldest == -1 || mapInfo[nTemp].nLastSuccess < mapInfo[nOldest].nLastSuccess)
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nOldest = nTemp;
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}
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return nOldest;
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}
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int CAddrMan::ShrinkNew(int nUBucket)
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{
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std::set<int> &vNew = vvNew[nUBucket];
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// first look for deletable items
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for (std::set<int>::iterator it = vNew.begin(); it != vNew.end(); it++)
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{
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CAddrInfo &info = mapInfo[*it];
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if (info.IsTerrible())
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{
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if (--info.nRefCount == 0)
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{
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SwapRandom(info.nRandomPos, vRandom.size()-1);
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vRandom.pop_back();
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mapAddr.erase(info);
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mapInfo.erase(*it);
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nNew--;
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}
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vNew.erase(it);
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return 0;
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}
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}
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// otherwise, select four randomly, and pick the oldest of those to replace
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int n[4] = {GetRandInt(vNew.size()), GetRandInt(vNew.size()), GetRandInt(vNew.size()), GetRandInt(vNew.size())};
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int nI = 0;
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int nOldest = -1;
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for (std::set<int>::iterator it = vNew.begin(); it != vNew.end(); it++)
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{
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if (nI == n[0] || nI == n[1] || nI == n[2] || nI == n[3])
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{
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if (nOldest == -1 || mapInfo[*it].nTime < mapInfo[nOldest].nTime)
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nOldest = *it;
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}
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nI++;
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}
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CAddrInfo &info = mapInfo[nOldest];
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if (--info.nRefCount == 0)
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{
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SwapRandom(info.nRandomPos, vRandom.size()-1);
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vRandom.pop_back();
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mapAddr.erase(info);
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mapInfo.erase(nOldest);
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nNew--;
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}
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vNew.erase(nOldest);
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return 1;
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}
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void CAddrMan::MakeTried(CAddrInfo& info, int nId, int nOrigin)
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{
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// remove the entry from all new buckets
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for (std::vector<std::set<int> >::iterator it = vvNew.begin(); it != vvNew.end(); it++)
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{
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if ((*it).erase(nId))
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info.nRefCount--;
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}
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nNew--;
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// what tried bucket to move the entry to
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int nKBucket = info.GetTriedBucket(nKey);
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std::vector<int> &vTried = vvTried[nKBucket];
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// first check whether there is place to just add it
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if (vTried.size() < ADDRMAN_TRIED_BUCKET_SIZE)
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{
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vTried.push_back(nId);
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nTried++;
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info.fInTried = true;
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return;
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}
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// otherwise, find an item to evict
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int nPos = SelectTried(nKBucket);
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// find which new bucket it belongs to
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int nUBucket = mapInfo[vTried[nPos]].GetNewBucket(nKey);
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std::set<int> &vNew = vvNew[nUBucket];
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// remove the to-be-replaced tried entry from the tried set
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CAddrInfo& infoOld = mapInfo[vTried[nPos]];
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infoOld.fInTried = false;
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infoOld.nRefCount = 1;
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// do not update nTried, as we are going to move something else there immediately
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// check whether there is place in that one,
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if (vNew.size() < ADDRMAN_NEW_BUCKET_SIZE)
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{
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// if so, move it back there
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vNew.insert(vTried[nPos]);
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} else {
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// otherwise, move it to the new bucket nId came from (there is certainly place there)
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vvNew[nOrigin].insert(vTried[nPos]);
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}
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nNew++;
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vTried[nPos] = nId;
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// we just overwrote an entry in vTried; no need to update nTried
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info.fInTried = true;
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return;
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}
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void CAddrMan::Good_(const CService &addr, int64 nTime)
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{
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// printf("Good: addr=%s\n", addr.ToString().c_str());
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int nId;
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CAddrInfo *pinfo = Find(addr, &nId);
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// if not found, bail out
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if (!pinfo)
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return;
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CAddrInfo &info = *pinfo;
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// check whether we are talking about the exact same CService (including same port)
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if (info != addr)
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return;
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// update info
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info.nLastSuccess = nTime;
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info.nLastTry = nTime;
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info.nTime = nTime;
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info.nAttempts = 0;
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// if it is already in the tried set, don't do anything else
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if (info.fInTried)
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return;
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// find a bucket it is in now
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int nRnd = GetRandInt(vvNew.size());
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int nUBucket = -1;
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for (int n = 0; n < vvNew.size(); n++)
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{
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int nB = (n+nRnd) % vvNew.size();
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std::set<int> &vNew = vvNew[nB];
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if (vNew.count(nId))
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{
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nUBucket = nB;
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break;
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}
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}
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// if no bucket is found, something bad happened;
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// TODO: maybe re-add the node, but for now, just bail out
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if (nUBucket == -1) return;
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printf("Moving %s to tried\n", addr.ToString().c_str());
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// move nId to the tried tables
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MakeTried(info, nId, nUBucket);
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}
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bool CAddrMan::Add_(const CAddress &addr, const CNetAddr& source, int64 nTimePenalty)
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{
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if (!addr.IsRoutable())
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return false;
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bool fNew = false;
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int nId;
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CAddrInfo *pinfo = Find(addr, &nId);
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if (pinfo)
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{
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// periodically update nTime
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bool fCurrentlyOnline = (GetAdjustedTime() - addr.nTime < 24 * 60 * 60);
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int64 nUpdateInterval = (fCurrentlyOnline ? 60 * 60 : 24 * 60 * 60);
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if (addr.nTime && (!pinfo->nTime || pinfo->nTime < addr.nTime - nUpdateInterval - nTimePenalty))
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pinfo->nTime = max((int64)0, addr.nTime - nTimePenalty);
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// add services
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pinfo->nServices |= addr.nServices;
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// do not update if no new information is present
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if (!addr.nTime || pinfo->nTime && addr.nTime <= pinfo->nTime)
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return false;
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// do not update if the entry was already in the "tried" table
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if (pinfo->fInTried)
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return false;
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// do not update if the max reference count is reached
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if (pinfo->nRefCount == ADDRMAN_NEW_BUCKETS_PER_ADDRESS)
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return false;
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// stochastic test: previous nRefCount == N: 2^N times harder to increase it
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int nFactor = 1;
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for (int n=0; n<pinfo->nRefCount; n++)
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nFactor *= 2;
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if (nFactor > 1 && (GetRandInt(nFactor) != 0))
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return false;
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} else {
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pinfo = Create(addr, source, &nId);
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pinfo->nTime = max((int64)0, (int64)pinfo->nTime - nTimePenalty);
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// printf("Added %s [nTime=%fhr]\n", pinfo->ToString().c_str(), (GetAdjustedTime() - pinfo->nTime) / 3600.0);
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nNew++;
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fNew = true;
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}
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int nUBucket = pinfo->GetNewBucket(nKey, source);
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std::set<int> &vNew = vvNew[nUBucket];
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if (!vNew.count(nId))
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{
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pinfo->nRefCount++;
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if (vNew.size() == ADDRMAN_NEW_BUCKET_SIZE)
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ShrinkNew(nUBucket);
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vvNew[nUBucket].insert(nId);
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}
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return fNew;
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}
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void CAddrMan::Attempt_(const CService &addr, int64 nTime)
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{
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CAddrInfo *pinfo = Find(addr);
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// if not found, bail out
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if (!pinfo)
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return;
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CAddrInfo &info = *pinfo;
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// check whether we are talking about the exact same CService (including same port)
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if (info != addr)
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return;
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// update info
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info.nLastTry = nTime;
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info.nAttempts++;
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}
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CAddress CAddrMan::Select_(int nUnkBias)
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{
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if (size() == 0)
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return CAddress();
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double nCorTried = sqrt(nTried) * (100.0 - nUnkBias);
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double nCorNew = sqrt(nNew) * nUnkBias;
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if ((nCorTried + nCorNew)*GetRandInt(1<<30)/(1<<30) < nCorTried)
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{
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// use a tried node
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double fChanceFactor = 1.0;
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while(1)
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{
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int nKBucket = GetRandInt(vvTried.size());
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std::vector<int> &vTried = vvTried[nKBucket];
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if (vTried.size() == 0) continue;
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int nPos = GetRandInt(vTried.size());
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CAddrInfo &info = mapInfo[vTried[nPos]];
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if (GetRandInt(1<<30) < fChanceFactor*info.GetChance()*(1<<30))
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return info;
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fChanceFactor *= 1.2;
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}
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} else {
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// use an new node
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double fChanceFactor = 1.0;
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while(1)
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{
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int nUBucket = GetRandInt(vvNew.size());
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std::set<int> &vNew = vvNew[nUBucket];
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if (vNew.size() == 0) continue;
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int nPos = GetRandInt(vNew.size());
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std::set<int>::iterator it = vNew.begin();
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while (nPos--)
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it++;
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CAddrInfo &info = mapInfo[*it];
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if (GetRandInt(1<<30) < fChanceFactor*info.GetChance()*(1<<30))
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return info;
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fChanceFactor *= 1.2;
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}
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}
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}
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#ifdef DEBUG_ADDRMAN
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int CAddrMan::Check_()
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{
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std::set<int> setTried;
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std::map<int, int> mapNew;
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if (vRandom.size() != nTried + nNew) return -7;
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for (std::map<int, CAddrInfo>::iterator it = mapInfo.begin(); it != mapInfo.end(); it++)
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{
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int n = (*it).first;
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CAddrInfo &info = (*it).second;
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if (info.fInTried)
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{
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if (!info.nLastSuccess) return -1;
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if (info.nRefCount) return -2;
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setTried.insert(n);
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} else {
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if (info.nRefCount < 0 || info.nRefCount > ADDRMAN_NEW_BUCKETS_PER_ADDRESS) return -3;
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if (!info.nRefCount) return -4;
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mapNew[n] = info.nRefCount;
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}
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if (mapAddr[info] != n) return -5;
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if (info.nRandomPos<0 || info.nRandomPos>=vRandom.size() || vRandom[info.nRandomPos] != n) return -14;
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if (info.nLastTry < 0) return -6;
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if (info.nLastSuccess < 0) return -8;
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}
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if (setTried.size() != nTried) return -9;
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if (mapNew.size() != nNew) return -10;
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for (int n=0; n<vvTried.size(); n++)
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{
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std::vector<int> &vTried = vvTried[n];
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for (std::vector<int>::iterator it = vTried.begin(); it != vTried.end(); it++)
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{
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if (!setTried.count(*it)) return -11;
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setTried.erase(*it);
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}
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||||
}
|
||||
|
||||
for (int n=0; n<vvNew.size(); n++)
|
||||
{
|
||||
std::set<int> &vNew = vvNew[n];
|
||||
for (std::set<int>::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<CAddress> &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<nNodes; n++)
|
||||
{
|
||||
int nRndPos = GetRandInt(vRandom.size() - n) + n;
|
||||
SwapRandom(n, nRndPos);
|
||||
vAddr.push_back(mapInfo[vRandom[n]]);
|
||||
}
|
||||
}
|
||||
|
||||
void CAddrMan::Connected_(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
|
||||
int64 nUpdateInterval = 20 * 60;
|
||||
if (nTime - info.nTime > nUpdateInterval)
|
||||
info.nTime = nTime;
|
||||
}
|
||||
Reference in New Issue
Block a user