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bitcoin/src/addrman.cpp

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// Copyright (c) 2012 Pieter Wuille
// Copyright (c) 2012-2019 The Bitcoin Core developers
// 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>
int CAddrInfo::GetTriedBucket(const uint256& nKey) const
{
uint64_t hash1 = (CHashWriter(SER_GETHASH, 0) << nKey << GetKey()).GetCheapHash();
uint64_t hash2 = (CHashWriter(SER_GETHASH, 0) << nKey << GetGroup() << (hash1 % ADDRMAN_TRIED_BUCKETS_PER_GROUP)).GetCheapHash();
return hash2 % ADDRMAN_TRIED_BUCKET_COUNT;
}
int CAddrInfo::GetNewBucket(const uint256& nKey, const CNetAddr& src) const
{
std::vector<unsigned char> vchSourceGroupKey = src.GetGroup();
uint64_t hash1 = (CHashWriter(SER_GETHASH, 0) << nKey << GetGroup() << vchSourceGroupKey).GetCheapHash();
uint64_t hash2 = (CHashWriter(SER_GETHASH, 0) << nKey << vchSourceGroupKey << (hash1 % ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP)).GetCheapHash();
return hash2 % ADDRMAN_NEW_BUCKET_COUNT;
}
int CAddrInfo::GetBucketPosition(const uint256 &nKey, bool fNew, int nBucket) const
{
uint64_t hash1 = (CHashWriter(SER_GETHASH, 0) << nKey << (fNew ? 'N' : 'K') << nBucket << GetKey()).GetCheapHash();
return hash1 % ADDRMAN_BUCKET_SIZE;
}
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 nSinceLastTry = std::max<int64_t>(nNow - nLastTry, 0);
// deprioritize very recent attempts away
if (nSinceLastTry < 60 * 10)
fChance *= 0.01;
// deprioritize 66% after each failed attempt, but at most 1/28th to avoid the search taking forever or overly penalizing outages.
fChance *= pow(0.66, std::min(nAttempts, 8));
return fChance;
}
CAddrInfo* CAddrMan::Find(const CNetAddr& addr, int* pnId)
{
std::map<CNetAddr, int>::iterator it = mapAddr.find(addr);
if (it == mapAddr.end())
return nullptr;
if (pnId)
*pnId = (*it).second;
std::map<int, CAddrInfo>::iterator it2 = mapInfo.find((*it).second);
if (it2 != mapInfo.end())
return &(*it2).second;
return nullptr;
}
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;
}
void CAddrMan::Delete(int nId)
{
assert(mapInfo.count(nId) != 0);
CAddrInfo& info = mapInfo[nId];
assert(!info.fInTried);
assert(info.nRefCount == 0);
SwapRandom(info.nRandomPos, vRandom.size() - 1);
vRandom.pop_back();
mapAddr.erase(info);
mapInfo.erase(nId);
nNew--;
}
void CAddrMan::ClearNew(int nUBucket, int nUBucketPos)
{
// if there is an entry in the specified bucket, delete it.
if (vvNew[nUBucket][nUBucketPos] != -1) {
int nIdDelete = vvNew[nUBucket][nUBucketPos];
CAddrInfo& infoDelete = mapInfo[nIdDelete];
assert(infoDelete.nRefCount > 0);
infoDelete.nRefCount--;
vvNew[nUBucket][nUBucketPos] = -1;
if (infoDelete.nRefCount == 0) {
Delete(nIdDelete);
}
}
}
void CAddrMan::MakeTried(CAddrInfo& info, int nId)
{
// remove the entry from all new buckets
for (int bucket = 0; bucket < ADDRMAN_NEW_BUCKET_COUNT; bucket++) {
int pos = info.GetBucketPosition(nKey, true, bucket);
if (vvNew[bucket][pos] == nId) {
vvNew[bucket][pos] = -1;
info.nRefCount--;
}
}
nNew--;
assert(info.nRefCount == 0);
// which tried bucket to move the entry to
int nKBucket = info.GetTriedBucket(nKey);
int nKBucketPos = info.GetBucketPosition(nKey, false, nKBucket);
// first make space to add it (the existing tried entry there is moved to new, deleting whatever is there).
if (vvTried[nKBucket][nKBucketPos] != -1) {
// find an item to evict
int nIdEvict = vvTried[nKBucket][nKBucketPos];
assert(mapInfo.count(nIdEvict) == 1);
CAddrInfo& infoOld = mapInfo[nIdEvict];
// Remove the to-be-evicted item from the tried set.
infoOld.fInTried = false;
vvTried[nKBucket][nKBucketPos] = -1;
nTried--;
// find which new bucket it belongs to
int nUBucket = infoOld.GetNewBucket(nKey);
int nUBucketPos = infoOld.GetBucketPosition(nKey, true, nUBucket);
ClearNew(nUBucket, nUBucketPos);
assert(vvNew[nUBucket][nUBucketPos] == -1);
// Enter it into the new set again.
infoOld.nRefCount = 1;
vvNew[nUBucket][nUBucketPos] = nIdEvict;
nNew++;
}
assert(vvTried[nKBucket][nKBucketPos] == -1);
vvTried[nKBucket][nKBucketPos] = nId;
nTried++;
info.fInTried = true;
}
void CAddrMan::Good_(const CService& addr, bool test_before_evict, int64_t nTime)
{
int nId;
nLastGood = nTime;
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 = insecure_rand.randrange(ADDRMAN_NEW_BUCKET_COUNT);
int nUBucket = -1;
for (unsigned int n = 0; n < ADDRMAN_NEW_BUCKET_COUNT; n++) {
int nB = (n + nRnd) % ADDRMAN_NEW_BUCKET_COUNT;
int nBpos = info.GetBucketPosition(nKey, true, nB);
if (vvNew[nB][nBpos] == 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;
// which tried bucket to move the entry to
int tried_bucket = info.GetTriedBucket(nKey);
int tried_bucket_pos = info.GetBucketPosition(nKey, false, tried_bucket);
// Will moving this address into tried evict another entry?
if (test_before_evict && (vvTried[tried_bucket][tried_bucket_pos] != -1)) {
// Output the entry we'd be colliding with, for debugging purposes
auto colliding_entry = mapInfo.find(vvTried[tried_bucket][tried_bucket_pos]);
LogPrint(BCLog::ADDRMAN, "Collision inserting element into tried table (%s), moving %s to m_tried_collisions=%d\n", colliding_entry != mapInfo.end() ? colliding_entry->second.ToString() : "", addr.ToString(), m_tried_collisions.size());
if (m_tried_collisions.size() < ADDRMAN_SET_TRIED_COLLISION_SIZE) {
m_tried_collisions.insert(nId);
}
} else {
LogPrint(BCLog::ADDRMAN, "Moving %s to tried\n", addr.ToString());
// move nId to the tried tables
MakeTried(info, nId);
}
}
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);
// Do not set a penalty for a source's self-announcement
if (addr == source) {
nTimePenalty = 0;
}
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 = std::max((int64_t)0, addr.nTime - nTimePenalty);
// add services
pinfo->nServices = ServiceFlags(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 && (insecure_rand.randrange(nFactor) != 0))
return false;
} else {
pinfo = Create(addr, source, &nId);
pinfo->nTime = std::max((int64_t)0, (int64_t)pinfo->nTime - nTimePenalty);
nNew++;
fNew = true;
}
int nUBucket = pinfo->GetNewBucket(nKey, source);
int nUBucketPos = pinfo->GetBucketPosition(nKey, true, nUBucket);
if (vvNew[nUBucket][nUBucketPos] != nId) {
bool fInsert = vvNew[nUBucket][nUBucketPos] == -1;
if (!fInsert) {
CAddrInfo& infoExisting = mapInfo[vvNew[nUBucket][nUBucketPos]];
if (infoExisting.IsTerrible() || (infoExisting.nRefCount > 1 && pinfo->nRefCount == 0)) {
// Overwrite the existing new table entry.
fInsert = true;
}
}
if (fInsert) {
ClearNew(nUBucket, nUBucketPos);
pinfo->nRefCount++;
vvNew[nUBucket][nUBucketPos] = nId;
} else {
if (pinfo->nRefCount == 0) {
Delete(nId);
}
}
}
return fNew;
}
void CAddrMan::Attempt_(const CService& addr, bool fCountFailure, 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;
if (fCountFailure && info.nLastCountAttempt < nLastGood) {
info.nLastCountAttempt = nTime;
info.nAttempts++;
}
}
CAddrInfo CAddrMan::Select_(bool newOnly)
{
if (size() == 0)
return CAddrInfo();
if (newOnly && nNew == 0)
return CAddrInfo();
// Use a 50% chance for choosing between tried and new table entries.
if (!newOnly &&
(nTried > 0 && (nNew == 0 || insecure_rand.randbool() == 0))) {
// use a tried node
double fChanceFactor = 1.0;
while (1) {
int nKBucket = insecure_rand.randrange(ADDRMAN_TRIED_BUCKET_COUNT);
int nKBucketPos = insecure_rand.randrange(ADDRMAN_BUCKET_SIZE);
while (vvTried[nKBucket][nKBucketPos] == -1) {
nKBucket = (nKBucket + insecure_rand.randbits(ADDRMAN_TRIED_BUCKET_COUNT_LOG2)) % ADDRMAN_TRIED_BUCKET_COUNT;
nKBucketPos = (nKBucketPos + insecure_rand.randbits(ADDRMAN_BUCKET_SIZE_LOG2)) % ADDRMAN_BUCKET_SIZE;
}
int nId = vvTried[nKBucket][nKBucketPos];
assert(mapInfo.count(nId) == 1);
CAddrInfo& info = mapInfo[nId];
if (insecure_rand.randbits(30) < fChanceFactor * info.GetChance() * (1 << 30))
return info;
fChanceFactor *= 1.2;
}
} else {
// use a new node
double fChanceFactor = 1.0;
while (1) {
int nUBucket = insecure_rand.randrange(ADDRMAN_NEW_BUCKET_COUNT);
int nUBucketPos = insecure_rand.randrange(ADDRMAN_BUCKET_SIZE);
while (vvNew[nUBucket][nUBucketPos] == -1) {
nUBucket = (nUBucket + insecure_rand.randbits(ADDRMAN_NEW_BUCKET_COUNT_LOG2)) % ADDRMAN_NEW_BUCKET_COUNT;
nUBucketPos = (nUBucketPos + insecure_rand.randbits(ADDRMAN_BUCKET_SIZE_LOG2)) % ADDRMAN_BUCKET_SIZE;
}
int nId = vvNew[nUBucket][nUBucketPos];
assert(mapInfo.count(nId) == 1);
CAddrInfo& info = mapInfo[nId];
if (insecure_rand.randbits(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() != (size_t)(nTried + nNew))
return -7;
for (const auto& entry : mapInfo) {
int n = entry.first;
const CAddrInfo& info = entry.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 || (size_t)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() != (size_t)nTried)
return -9;
if (mapNew.size() != (size_t)nNew)
return -10;
for (int n = 0; n < ADDRMAN_TRIED_BUCKET_COUNT; n++) {
for (int i = 0; i < ADDRMAN_BUCKET_SIZE; i++) {
if (vvTried[n][i] != -1) {
if (!setTried.count(vvTried[n][i]))
return -11;
if (mapInfo[vvTried[n][i]].GetTriedBucket(nKey) != n)
return -17;
if (mapInfo[vvTried[n][i]].GetBucketPosition(nKey, false, n) != i)
return -18;
setTried.erase(vvTried[n][i]);
}
}
}
for (int n = 0; n < ADDRMAN_NEW_BUCKET_COUNT; n++) {
for (int i = 0; i < ADDRMAN_BUCKET_SIZE; i++) {
if (vvNew[n][i] != -1) {
if (!mapNew.count(vvNew[n][i]))
return -12;
if (mapInfo[vvNew[n][i]].GetBucketPosition(nKey, true, n) != i)
return -19;
if (--mapNew[vvNew[n][i]] == 0)
mapNew.erase(vvNew[n][i]);
}
}
}
if (setTried.size())
return -13;
if (mapNew.size())
return -15;
if (nKey.IsNull())
return -16;
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 = insecure_rand.randrange(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;
}
void CAddrMan::SetServices_(const CService& addr, ServiceFlags nServices)
{
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.nServices = nServices;
}
void CAddrMan::ResolveCollisions_()
{
for (std::set<int>::iterator it = m_tried_collisions.begin(); it != m_tried_collisions.end();) {
int id_new = *it;
bool erase_collision = false;
// If id_new not found in mapInfo remove it from m_tried_collisions
if (mapInfo.count(id_new) != 1) {
erase_collision = true;
} else {
CAddrInfo& info_new = mapInfo[id_new];
// Which tried bucket to move the entry to.
int tried_bucket = info_new.GetTriedBucket(nKey);
int tried_bucket_pos = info_new.GetBucketPosition(nKey, false, tried_bucket);
if (!info_new.IsValid()) { // id_new may no longer map to a valid address
erase_collision = true;
} else if (vvTried[tried_bucket][tried_bucket_pos] != -1) { // The position in the tried bucket is not empty
// Get the to-be-evicted address that is being tested
int id_old = vvTried[tried_bucket][tried_bucket_pos];
CAddrInfo& info_old = mapInfo[id_old];
// Has successfully connected in last X hours
if (GetAdjustedTime() - info_old.nLastSuccess < ADDRMAN_REPLACEMENT_HOURS*(60*60)) {
erase_collision = true;
} else if (GetAdjustedTime() - info_old.nLastTry < ADDRMAN_REPLACEMENT_HOURS*(60*60)) { // attempted to connect and failed in last X hours
// Give address at least 60 seconds to successfully connect
if (GetAdjustedTime() - info_old.nLastTry > 60) {
LogPrint(BCLog::ADDRMAN, "Replacing %s with %s in tried table\n", info_old.ToString(), info_new.ToString());
// Replaces an existing address already in the tried table with the new address
Good_(info_new, false, GetAdjustedTime());
erase_collision = true;
}
} else if (GetAdjustedTime() - info_new.nLastSuccess > ADDRMAN_TEST_WINDOW) {
// If the collision hasn't resolved in some reasonable amount of time,
// just evict the old entry -- we must not be able to
// connect to it for some reason.
LogPrint(BCLog::ADDRMAN, "Unable to test; replacing %s with %s in tried table anyway\n", info_old.ToString(), info_new.ToString());
Good_(info_new, false, GetAdjustedTime());
erase_collision = true;
}
} else { // Collision is not actually a collision anymore
Good_(info_new, false, GetAdjustedTime());
erase_collision = true;
}
}
if (erase_collision) {
m_tried_collisions.erase(it++);
} else {
it++;
}
}
}
CAddrInfo CAddrMan::SelectTriedCollision_()
{
if (m_tried_collisions.size() == 0) return CAddrInfo();
std::set<int>::iterator it = m_tried_collisions.begin();
// Selects a random element from m_tried_collisions
std::advance(it, insecure_rand.randrange(m_tried_collisions.size()));
int id_new = *it;
// If id_new not found in mapInfo remove it from m_tried_collisions
if (mapInfo.count(id_new) != 1) {
m_tried_collisions.erase(it);
return CAddrInfo();
}
CAddrInfo& newInfo = mapInfo[id_new];
// which tried bucket to move the entry to
int tried_bucket = newInfo.GetTriedBucket(nKey);
int tried_bucket_pos = newInfo.GetBucketPosition(nKey, false, tried_bucket);
int id_old = vvTried[tried_bucket][tried_bucket_pos];
return mapInfo[id_old];
}
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