dogecoin/src/addrman.cpp
Wladimir J. van der Laan 5eaaa83ac1 Kill insecure_random and associated global state
There are only a few uses of `insecure_random` outside the tests.
This PR replaces uses of insecure_random (and its accompanying global
state) in the core code with an FastRandomContext that is automatically
seeded on creation.

This is meant to be used for inner loops. The FastRandomContext
can be in the outer scope, or the class itself, then rand32() is used
inside the loop. Useful e.g. for pushing addresses in CNode or the fee
rounding, or randomization for coin selection.

As a context is created per purpose, thus it gets rid of
cross-thread unprotected shared usage of a single set of globals, this
should also get rid of the potential race conditions.

- I'd say TxMempool::check is not called enough to warrant using a special
  fast random context, this is switched to GetRand() (open for
  discussion...)

- The use of `insecure_rand` in ConnectThroughProxy has been replaced by
  an atomic integer counter. The only goal here is to have a different
  credentials pair for each connection to go on a different Tor circuit,
  it does not need to be random nor unpredictable.

- To avoid having a FastRandomContext on every CNode, the context is
  passed into PushAddress as appropriate.

There remains an insecure_random for test usage in `test_random.h`.
2016-10-17 13:08:35 +02:00

531 lines
16 KiB
C++

// Copyright (c) 2012 Pieter Wuille
// Copyright (c) 2012-2015 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"
#include "streams.h"
int CAddrInfo::GetTriedBucket(const uint256& nKey) const
{
uint64_t hash1 = (CHashWriter(SER_GETHASH, 0) << nKey << GetKey()).GetHash().GetCheapHash();
uint64_t hash2 = (CHashWriter(SER_GETHASH, 0) << nKey << GetGroup() << (hash1 % ADDRMAN_TRIED_BUCKETS_PER_GROUP)).GetHash().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).GetHash().GetCheapHash();
uint64_t hash2 = (CHashWriter(SER_GETHASH, 0) << nKey << vchSourceGroupKey << (hash1 % ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP)).GetHash().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()).GetHash().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 nSinceLastSeen = nNow - nTime;
int64_t nSinceLastTry = nNow - nLastTry;
if (nSinceLastSeen < 0)
nSinceLastSeen = 0;
if (nSinceLastTry < 0)
nSinceLastTry = 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 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;
}
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, 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 = RandomInt(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;
LogPrint("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 penality 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 && (RandomInt(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 || RandomInt(2) == 0))) {
// use a tried node
double fChanceFactor = 1.0;
while (1) {
int nKBucket = RandomInt(ADDRMAN_TRIED_BUCKET_COUNT);
int nKBucketPos = RandomInt(ADDRMAN_BUCKET_SIZE);
while (vvTried[nKBucket][nKBucketPos] == -1) {
nKBucket = (nKBucket + insecure_rand.rand32()) % ADDRMAN_TRIED_BUCKET_COUNT;
nKBucketPos = (nKBucketPos + insecure_rand.rand32()) % ADDRMAN_BUCKET_SIZE;
}
int nId = vvTried[nKBucket][nKBucketPos];
assert(mapInfo.count(nId) == 1);
CAddrInfo& info = mapInfo[nId];
if (RandomInt(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 = RandomInt(ADDRMAN_NEW_BUCKET_COUNT);
int nUBucketPos = RandomInt(ADDRMAN_BUCKET_SIZE);
while (vvNew[nUBucket][nUBucketPos] == -1) {
nUBucket = (nUBucket + insecure_rand.rand32()) % ADDRMAN_NEW_BUCKET_COUNT;
nUBucketPos = (nUBucketPos + insecure_rand.rand32()) % ADDRMAN_BUCKET_SIZE;
}
int nId = vvNew[nUBucket][nUBucketPos];
assert(mapInfo.count(nId) == 1);
CAddrInfo& info = mapInfo[nId];
if (RandomInt(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 < 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 = RandomInt(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;
}
int CAddrMan::RandomInt(int nMax){
return GetRandInt(nMax);
}