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litecoin/src/addrman.cpp

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// Copyright (c) 2012 Pieter Wuille
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "addrman.h"
#include "hash.h"
#include "serialize.h"
#include "streams.h"
using namespace std;
int CAddrInfo::GetTriedBucket(const std::vector<unsigned char>& nKey) const
{
CDataStream ss1(SER_GETHASH, 0);
std::vector<unsigned char> vchKey = GetKey();
ss1 << nKey << vchKey;
uint64_t hash1 = Hash(ss1.begin(), ss1.end()).GetCheapHash();
CDataStream ss2(SER_GETHASH, 0);
std::vector<unsigned char> vchGroupKey = GetGroup();
ss2 << nKey << vchGroupKey << (hash1 % ADDRMAN_TRIED_BUCKETS_PER_GROUP);
uint64_t hash2 = Hash(ss2.begin(), ss2.end()).GetCheapHash();
return hash2 % ADDRMAN_TRIED_BUCKET_COUNT;
}
int CAddrInfo::GetNewBucket(const std::vector<unsigned char>& nKey, const CNetAddr& src) const
{
CDataStream ss1(SER_GETHASH, 0);
std::vector<unsigned char> vchGroupKey = GetGroup();
std::vector<unsigned char> vchSourceGroupKey = src.GetGroup();
ss1 << nKey << vchGroupKey << vchSourceGroupKey;
uint64_t hash1 = Hash(ss1.begin(), ss1.end()).GetCheapHash();
CDataStream ss2(SER_GETHASH, 0);
ss2 << nKey << vchSourceGroupKey << (hash1 % ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP);
uint64_t hash2 = Hash(ss2.begin(), ss2.end()).GetCheapHash();
return hash2 % ADDRMAN_NEW_BUCKET_COUNT;
}
bool CAddrInfo::IsTerrible(int64_t nNow) const
{
if (nLastTry && nLastTry >= nNow - 60) // never remove things tried in 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 * 24 * 60 * 60) // not seen in recent history
return true;
if (nLastSuccess == 0 && nAttempts >= ADDRMAN_RETRIES) // tried N times and never a success
return true;
if (nNow - nLastSuccess > ADDRMAN_MIN_FAIL_DAYS * 24 * 60 * 60 && nAttempts >= ADDRMAN_MAX_FAILURES) // N successive failures in the last week
return true;
return false;
}
double CAddrInfo::GetChance(int64_t nNow) const
{
double fChance = 1.0;
int64_t nSinceLastSeen = nNow - nTime;
int64_t 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 < nAttempts; n++)
fChance /= 1.5;
return fChance;
}
CAddrInfo* CAddrMan::Find(const CNetAddr& addr, int* pnId)
{
std::map<CNetAddr, int>::iterator it = mapAddr.find(addr);
if (it == mapAddr.end())
return NULL;
if (pnId)
*pnId = (*it).second;
std::map<int, CAddrInfo>::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(unsigned int nRndPos1, unsigned int nRndPos2)
{
if (nRndPos1 == nRndPos2)
return;
assert(nRndPos1 < vRandom.size() && nRndPos2 < vRandom.size());
int nId1 = vRandom[nRndPos1];
int nId2 = vRandom[nRndPos2];
assert(mapInfo.count(nId1) == 1);
assert(mapInfo.count(nId2) == 1);
mapInfo[nId1].nRandomPos = nRndPos2;
mapInfo[nId2].nRandomPos = nRndPos1;
vRandom[nRndPos1] = nId2;
vRandom[nRndPos2] = nId1;
}
int CAddrMan::SelectTried(int nKBucket)
{
std::vector<int>& vTried = vvTried[nKBucket];
// randomly shuffle the first few elements (using the entire list)
// find the least recently tried among them
int64_t nOldest = -1;
int nOldestPos = -1;
for (unsigned int i = 0; i < ADDRMAN_TRIED_ENTRIES_INSPECT_ON_EVICT && i < vTried.size(); i++) {
int nPos = GetRandInt(vTried.size() - i) + i;
int nTemp = vTried[nPos];
vTried[nPos] = vTried[i];
vTried[i] = nTemp;
assert(nOldest == -1 || mapInfo.count(nTemp) == 1);
if (nOldest == -1 || mapInfo[nTemp].nLastSuccess < mapInfo[nOldest].nLastSuccess) {
nOldest = nTemp;
nOldestPos = nPos;
}
}
return nOldestPos;
}
int CAddrMan::ShrinkNew(int nUBucket)
{
assert(nUBucket >= 0 && (unsigned int)nUBucket < vvNew.size());
std::set<int>& vNew = vvNew[nUBucket];
// first look for deletable items
for (std::set<int>::iterator it = vNew.begin(); it != vNew.end(); it++) {
assert(mapInfo.count(*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<int>::iterator it = vNew.begin(); it != vNew.end(); it++) {
if (nI == n[0] || nI == n[1] || nI == n[2] || nI == n[3]) {
assert(nOldest == -1 || mapInfo.count(*it) == 1);
if (nOldest == -1 || mapInfo[*it].nTime < mapInfo[nOldest].nTime)
nOldest = *it;
}
nI++;
}
assert(mapInfo.count(nOldest) == 1);
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)
{
assert(vvNew[nOrigin].count(nId) == 1);
// remove the entry from all new buckets
for (std::vector<std::set<int> >::iterator it = vvNew.begin(); it != vvNew.end(); it++) {
if ((*it).erase(nId))
info.nRefCount--;
}
nNew--;
assert(info.nRefCount == 0);
// which tried bucket to move the entry to
int nKBucket = info.GetTriedBucket(nKey);
std::vector<int>& 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
assert(mapInfo.count(vTried[nPos]) == 1);
int nUBucket = mapInfo[vTried[nPos]].GetNewBucket(nKey);
std::set<int>& 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_t nTime)
{
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.nAttempts = 0;
// nTime is not updated here, to avoid leaking information about
// currently-connected peers.
// 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 (unsigned int n = 0; n < vvNew.size(); n++) {
int nB = (n + nRnd) % vvNew.size();
std::set<int>& 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;
LogPrint("addrman", "Moving %s to tried\n", addr.ToString());
// move nId to the tried tables
MakeTried(info, nId, nUBucket);
}
bool CAddrMan::Add_(const CAddress& addr, const CNetAddr& source, int64_t 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_t nUpdateInterval = (fCurrentlyOnline ? 60 * 60 : 24 * 60 * 60);
if (addr.nTime && (!pinfo->nTime || pinfo->nTime < addr.nTime - nUpdateInterval - nTimePenalty))
pinfo->nTime = max((int64_t)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; n < pinfo->nRefCount; n++)
nFactor *= 2;
if (nFactor > 1 && (GetRandInt(nFactor) != 0))
return false;
} else {
pinfo = Create(addr, source, &nId);
pinfo->nTime = max((int64_t)0, (int64_t)pinfo->nTime - nTimePenalty);
nNew++;
fNew = true;
}
int nUBucket = pinfo->GetNewBucket(nKey, source);
std::set<int>& 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_t 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<int>& vTried = vvTried[nKBucket];
if (vTried.size() == 0)
continue;
int nPos = GetRandInt(vTried.size());
assert(mapInfo.count(vTried[nPos]) == 1);
CAddrInfo& info = mapInfo[vTried[nPos]];
if (GetRandInt(1 << 30) < fChanceFactor * info.GetChance() * (1 << 30))
return info;
fChanceFactor *= 1.2;
}
} else {
// use a new node
double fChanceFactor = 1.0;
while (1) {
int nUBucket = GetRandInt(vvNew.size());
std::set<int>& vNew = vvNew[nUBucket];
if (vNew.size() == 0)
continue;
int nPos = GetRandInt(vNew.size());
std::set<int>::iterator it = vNew.begin();
while (nPos--)
it++;
assert(mapInfo.count(*it) == 1);
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<int> setTried;
std::map<int, int> mapNew;
if (vRandom.size() != nTried + nNew)
return -7;
for (std::map<int, CAddrInfo>::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 < vvTried.size(); n++) {
std::vector<int>& vTried = vvTried[n];
for (std::vector<int>::iterator it = vTried.begin(); it != vTried.end(); it++) {
if (!setTried.count(*it))
return -11;
setTried.erase(*it);
}
}
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)
{
unsigned int nNodes = ADDRMAN_GETADDR_MAX_PCT * vRandom.size() / 100;
if (nNodes > ADDRMAN_GETADDR_MAX)
nNodes = ADDRMAN_GETADDR_MAX;
// gather a list of random nodes, skipping those of low quality
for (unsigned int n = 0; n < vRandom.size(); n++) {
if (vAddr.size() >= nNodes)
break;
int nRndPos = GetRandInt(vRandom.size() - n) + n;
SwapRandom(n, nRndPos);
assert(mapInfo.count(vRandom[n]) == 1);
const CAddrInfo& ai = mapInfo[vRandom[n]];
if (!ai.IsTerrible())
vAddr.push_back(ai);
}
}
void CAddrMan::Connected_(const CService& addr, int64_t 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_t nUpdateInterval = 20 * 60;
if (nTime - info.nTime > nUpdateInterval)
info.nTime = nTime;
}
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