neobytes/src/addrman.h
EthanHeilman 1534d9a83c Creates unittests for addrman, makes addrman testable.
Adds several unittests for addrman to verify it works as expected.
Makes small modifications to addrman to allow deterministic and targeted tests.
2015-09-24 15:20:48 -04:00

581 lines
18 KiB
C++

// 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.
#ifndef BITCOIN_ADDRMAN_H
#define BITCOIN_ADDRMAN_H
#include "netbase.h"
#include "protocol.h"
#include "random.h"
#include "sync.h"
#include "timedata.h"
#include "util.h"
#include <map>
#include <set>
#include <stdint.h>
#include <vector>
/**
* Extended statistics about a CAddress
*/
class CAddrInfo : public CAddress
{
public:
//! last try whatsoever by us (memory only)
int64_t nLastTry;
private:
//! where knowledge about this address first came from
CNetAddr source;
//! last successful connection by us
int64_t nLastSuccess;
//! connection attempts since last successful attempt
int nAttempts;
//! reference count in new sets (memory only)
int nRefCount;
//! in tried set? (memory only)
bool fInTried;
//! position in vRandom
int nRandomPos;
friend class CAddrMan;
public:
ADD_SERIALIZE_METHODS;
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
READWRITE(*(CAddress*)this);
READWRITE(source);
READWRITE(nLastSuccess);
READWRITE(nAttempts);
}
void Init()
{
nLastSuccess = 0;
nLastTry = 0;
nAttempts = 0;
nRefCount = 0;
fInTried = false;
nRandomPos = -1;
}
CAddrInfo(const CAddress &addrIn, const CNetAddr &addrSource) : CAddress(addrIn), source(addrSource)
{
Init();
}
CAddrInfo() : CAddress(), source()
{
Init();
}
//! Calculate in which "tried" bucket this entry belongs
int GetTriedBucket(const uint256 &nKey) const;
//! Calculate in which "new" bucket this entry belongs, given a certain source
int GetNewBucket(const uint256 &nKey, const CNetAddr& src) const;
//! Calculate in which "new" bucket this entry belongs, using its default source
int GetNewBucket(const uint256 &nKey) const
{
return GetNewBucket(nKey, source);
}
//! Calculate in which position of a bucket to store this entry.
int GetBucketPosition(const uint256 &nKey, bool fNew, int nBucket) const;
//! Determine whether the statistics about this entry are bad enough so that it can just be deleted
bool IsTerrible(int64_t nNow = GetAdjustedTime()) const;
//! Calculate the relative chance this entry should be given when selecting nodes to connect to
double GetChance(int64_t nNow = GetAdjustedTime()) const;
};
/** Stochastic address manager
*
* Design goals:
* * Keep the address tables in-memory, and asynchronously dump the entire table to peers.dat.
* * Make sure no (localized) attacker can fill the entire table with his nodes/addresses.
*
* To that end:
* * Addresses are organized into buckets.
* * Addresses that have not yet been tried go into 1024 "new" buckets.
* * Based on the address range (/16 for IPv4) of the source of information, 64 buckets are selected at random.
* * The actual bucket is chosen from one of these, based on the range in which the address itself is located.
* * One single address can occur in up to 8 different buckets to increase selection chances for addresses that
* are seen frequently. The chance for increasing this multiplicity decreases exponentially.
* * When adding a new address to a full bucket, a randomly chosen entry (with a bias favoring less recently seen
* ones) is removed from it first.
* * Addresses of nodes that are known to be accessible go into 256 "tried" buckets.
* * Each address range selects at random 8 of these buckets.
* * The actual bucket is chosen from one of these, based on the full address.
* * When adding a new good address to a full bucket, a randomly chosen entry (with a bias favoring less recently
* tried ones) is evicted from it, back to the "new" buckets.
* * Bucket selection is based on cryptographic hashing, using a randomly-generated 256-bit key, which should not
* be observable by adversaries.
* * Several indexes are kept for high performance. Defining DEBUG_ADDRMAN will introduce frequent (and expensive)
* consistency checks for the entire data structure.
*/
//! total number of buckets for tried addresses
#define ADDRMAN_TRIED_BUCKET_COUNT 256
//! total number of buckets for new addresses
#define ADDRMAN_NEW_BUCKET_COUNT 1024
//! maximum allowed number of entries in buckets for new and tried addresses
#define ADDRMAN_BUCKET_SIZE 64
//! over how many buckets entries with tried addresses from a single group (/16 for IPv4) are spread
#define ADDRMAN_TRIED_BUCKETS_PER_GROUP 8
//! over how many buckets entries with new addresses originating from a single group are spread
#define ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP 64
//! in how many buckets for entries with new addresses a single address may occur
#define ADDRMAN_NEW_BUCKETS_PER_ADDRESS 8
//! how old addresses can maximally be
#define ADDRMAN_HORIZON_DAYS 30
//! after how many failed attempts we give up on a new node
#define ADDRMAN_RETRIES 3
//! how many successive failures are allowed ...
#define ADDRMAN_MAX_FAILURES 10
//! ... in at least this many days
#define ADDRMAN_MIN_FAIL_DAYS 7
//! the maximum percentage of nodes to return in a getaddr call
#define ADDRMAN_GETADDR_MAX_PCT 23
//! the maximum number of nodes to return in a getaddr call
#define ADDRMAN_GETADDR_MAX 2500
/**
* Stochastical (IP) address manager
*/
class CAddrMan
{
private:
//! critical section to protect the inner data structures
mutable CCriticalSection cs;
//! secret key to randomize bucket select with
uint256 nKey;
//! last used nId
int nIdCount;
//! table with information about all nIds
std::map<int, CAddrInfo> mapInfo;
//! find an nId based on its network address
std::map<CNetAddr, int> mapAddr;
//! randomly-ordered vector of all nIds
std::vector<int> vRandom;
// number of "tried" entries
int nTried;
//! list of "tried" buckets
int vvTried[ADDRMAN_TRIED_BUCKET_COUNT][ADDRMAN_BUCKET_SIZE];
//! number of (unique) "new" entries
int nNew;
//! list of "new" buckets
int vvNew[ADDRMAN_NEW_BUCKET_COUNT][ADDRMAN_BUCKET_SIZE];
protected:
//! Find an entry.
CAddrInfo* Find(const CNetAddr& addr, int *pnId = NULL);
//! find an entry, creating it if necessary.
//! nTime and nServices of the found node are updated, if necessary.
CAddrInfo* Create(const CAddress &addr, const CNetAddr &addrSource, int *pnId = NULL);
//! Swap two elements in vRandom.
void SwapRandom(unsigned int nRandomPos1, unsigned int nRandomPos2);
//! Move an entry from the "new" table(s) to the "tried" table
void MakeTried(CAddrInfo& info, int nId);
//! Delete an entry. It must not be in tried, and have refcount 0.
void Delete(int nId);
//! Clear a position in a "new" table. This is the only place where entries are actually deleted.
void ClearNew(int nUBucket, int nUBucketPos);
//! Mark an entry "good", possibly moving it from "new" to "tried".
void Good_(const CService &addr, int64_t nTime);
//! Add an entry to the "new" table.
bool Add_(const CAddress &addr, const CNetAddr& source, int64_t nTimePenalty);
//! Mark an entry as attempted to connect.
void Attempt_(const CService &addr, int64_t nTime);
//! Select an address to connect to, if newOnly is set to true, only the new table is selected from.
CAddrInfo Select_(bool newOnly);
#ifdef DEBUG_ADDRMAN
//! Perform consistency check. Returns an error code or zero.
int Check_();
#endif
//! Select several addresses at once.
void GetAddr_(std::vector<CAddress> &vAddr);
//! Mark an entry as currently-connected-to.
void Connected_(const CService &addr, int64_t nTime);
public:
/**
* serialized format:
* * version byte (currently 1)
* * 0x20 + nKey (serialized as if it were a vector, for backward compatibility)
* * nNew
* * nTried
* * number of "new" buckets XOR 2**30
* * all nNew addrinfos in vvNew
* * all nTried addrinfos in vvTried
* * for each bucket:
* * number of elements
* * for each element: index
*
* 2**30 is xorred with the number of buckets to make addrman deserializer v0 detect it
* as incompatible. This is necessary because it did not check the version number on
* deserialization.
*
* Notice that vvTried, mapAddr and vVector are never encoded explicitly;
* they are instead reconstructed from the other information.
*
* vvNew is serialized, but only used if ADDRMAN_UNKNOWN_BUCKET_COUNT didn't change,
* otherwise it is reconstructed as well.
*
* This format is more complex, but significantly smaller (at most 1.5 MiB), and supports
* changes to the ADDRMAN_ parameters without breaking the on-disk structure.
*
* We don't use ADD_SERIALIZE_METHODS since the serialization and deserialization code has
* very little in common.
*/
template<typename Stream>
void Serialize(Stream &s, int nType, int nVersionDummy) const
{
LOCK(cs);
unsigned char nVersion = 1;
s << nVersion;
s << ((unsigned char)32);
s << nKey;
s << nNew;
s << nTried;
int nUBuckets = ADDRMAN_NEW_BUCKET_COUNT ^ (1 << 30);
s << nUBuckets;
std::map<int, int> mapUnkIds;
int nIds = 0;
for (std::map<int, CAddrInfo>::const_iterator it = mapInfo.begin(); it != mapInfo.end(); it++) {
mapUnkIds[(*it).first] = nIds;
const CAddrInfo &info = (*it).second;
if (info.nRefCount) {
assert(nIds != nNew); // this means nNew was wrong, oh ow
s << info;
nIds++;
}
}
nIds = 0;
for (std::map<int, CAddrInfo>::const_iterator it = mapInfo.begin(); it != mapInfo.end(); it++) {
const CAddrInfo &info = (*it).second;
if (info.fInTried) {
assert(nIds != nTried); // this means nTried was wrong, oh ow
s << info;
nIds++;
}
}
for (int bucket = 0; bucket < ADDRMAN_NEW_BUCKET_COUNT; bucket++) {
int nSize = 0;
for (int i = 0; i < ADDRMAN_BUCKET_SIZE; i++) {
if (vvNew[bucket][i] != -1)
nSize++;
}
s << nSize;
for (int i = 0; i < ADDRMAN_BUCKET_SIZE; i++) {
if (vvNew[bucket][i] != -1) {
int nIndex = mapUnkIds[vvNew[bucket][i]];
s << nIndex;
}
}
}
}
template<typename Stream>
void Unserialize(Stream& s, int nType, int nVersionDummy)
{
LOCK(cs);
Clear();
unsigned char nVersion;
s >> nVersion;
unsigned char nKeySize;
s >> nKeySize;
if (nKeySize != 32) throw std::ios_base::failure("Incorrect keysize in addrman deserialization");
s >> nKey;
s >> nNew;
s >> nTried;
int nUBuckets = 0;
s >> nUBuckets;
if (nVersion != 0) {
nUBuckets ^= (1 << 30);
}
// Deserialize entries from the new table.
for (int n = 0; n < nNew; n++) {
CAddrInfo &info = mapInfo[n];
s >> info;
mapAddr[info] = n;
info.nRandomPos = vRandom.size();
vRandom.push_back(n);
if (nVersion != 1 || nUBuckets != ADDRMAN_NEW_BUCKET_COUNT) {
// In case the new table data cannot be used (nVersion unknown, or bucket count wrong),
// immediately try to give them a reference based on their primary source address.
int nUBucket = info.GetNewBucket(nKey);
int nUBucketPos = info.GetBucketPosition(nKey, true, nUBucket);
if (vvNew[nUBucket][nUBucketPos] == -1) {
vvNew[nUBucket][nUBucketPos] = n;
info.nRefCount++;
}
}
}
nIdCount = nNew;
// Deserialize entries from the tried table.
int nLost = 0;
for (int n = 0; n < nTried; n++) {
CAddrInfo info;
s >> info;
int nKBucket = info.GetTriedBucket(nKey);
int nKBucketPos = info.GetBucketPosition(nKey, false, nKBucket);
if (vvTried[nKBucket][nKBucketPos] == -1) {
info.nRandomPos = vRandom.size();
info.fInTried = true;
vRandom.push_back(nIdCount);
mapInfo[nIdCount] = info;
mapAddr[info] = nIdCount;
vvTried[nKBucket][nKBucketPos] = nIdCount;
nIdCount++;
} else {
nLost++;
}
}
nTried -= nLost;
// Deserialize positions in the new table (if possible).
for (int bucket = 0; bucket < nUBuckets; bucket++) {
int nSize = 0;
s >> nSize;
for (int n = 0; n < nSize; n++) {
int nIndex = 0;
s >> nIndex;
if (nIndex >= 0 && nIndex < nNew) {
CAddrInfo &info = mapInfo[nIndex];
int nUBucketPos = info.GetBucketPosition(nKey, true, bucket);
if (nVersion == 1 && nUBuckets == ADDRMAN_NEW_BUCKET_COUNT && vvNew[bucket][nUBucketPos] == -1 && info.nRefCount < ADDRMAN_NEW_BUCKETS_PER_ADDRESS) {
info.nRefCount++;
vvNew[bucket][nUBucketPos] = nIndex;
}
}
}
}
// Prune new entries with refcount 0 (as a result of collisions).
int nLostUnk = 0;
for (std::map<int, CAddrInfo>::const_iterator it = mapInfo.begin(); it != mapInfo.end(); ) {
if (it->second.fInTried == false && it->second.nRefCount == 0) {
std::map<int, CAddrInfo>::const_iterator itCopy = it++;
Delete(itCopy->first);
nLostUnk++;
} else {
it++;
}
}
if (nLost + nLostUnk > 0) {
LogPrint("addrman", "addrman lost %i new and %i tried addresses due to collisions\n", nLostUnk, nLost);
}
Check();
}
unsigned int GetSerializeSize(int nType, int nVersion) const
{
return (CSizeComputer(nType, nVersion) << *this).size();
}
void Clear()
{
std::vector<int>().swap(vRandom);
nKey = GetRandHash();
for (size_t bucket = 0; bucket < ADDRMAN_NEW_BUCKET_COUNT; bucket++) {
for (size_t entry = 0; entry < ADDRMAN_BUCKET_SIZE; entry++) {
vvNew[bucket][entry] = -1;
}
}
for (size_t bucket = 0; bucket < ADDRMAN_TRIED_BUCKET_COUNT; bucket++) {
for (size_t entry = 0; entry < ADDRMAN_BUCKET_SIZE; entry++) {
vvTried[bucket][entry] = -1;
}
}
nIdCount = 0;
nTried = 0;
nNew = 0;
}
CAddrMan()
{
Clear();
}
~CAddrMan()
{
nKey.SetNull();
}
//! Return the number of (unique) addresses in all tables.
size_t size() const
{
return vRandom.size();
}
//! Consistency check
void Check()
{
#ifdef DEBUG_ADDRMAN
{
LOCK(cs);
int err;
if ((err=Check_()))
LogPrintf("ADDRMAN CONSISTENCY CHECK FAILED!!! err=%i\n", err);
}
#endif
}
//! Add a single address.
bool Add(const CAddress &addr, const CNetAddr& source, int64_t nTimePenalty = 0)
{
bool fRet = false;
{
LOCK(cs);
Check();
fRet |= Add_(addr, source, nTimePenalty);
Check();
}
if (fRet)
LogPrint("addrman", "Added %s from %s: %i tried, %i new\n", addr.ToStringIPPort(), source.ToString(), nTried, nNew);
return fRet;
}
//! Add multiple addresses.
bool Add(const std::vector<CAddress> &vAddr, const CNetAddr& source, int64_t nTimePenalty = 0)
{
int nAdd = 0;
{
LOCK(cs);
Check();
for (std::vector<CAddress>::const_iterator it = vAddr.begin(); it != vAddr.end(); it++)
nAdd += Add_(*it, source, nTimePenalty) ? 1 : 0;
Check();
}
if (nAdd)
LogPrint("addrman", "Added %i addresses from %s: %i tried, %i new\n", nAdd, source.ToString(), nTried, nNew);
return nAdd > 0;
}
//! Mark an entry as accessible.
void Good(const CService &addr, int64_t nTime = GetAdjustedTime())
{
{
LOCK(cs);
Check();
Good_(addr, nTime);
Check();
}
}
//! Mark an entry as connection attempted to.
void Attempt(const CService &addr, int64_t nTime = GetAdjustedTime())
{
{
LOCK(cs);
Check();
Attempt_(addr, nTime);
Check();
}
}
/**
* Choose an address to connect to.
*/
CAddrInfo Select(bool newOnly = false)
{
CAddrInfo addrRet;
{
LOCK(cs);
Check();
addrRet = Select_(newOnly);
Check();
}
return addrRet;
}
//! Return a bunch of addresses, selected at random.
std::vector<CAddress> GetAddr()
{
Check();
std::vector<CAddress> vAddr;
{
LOCK(cs);
GetAddr_(vAddr);
}
Check();
return vAddr;
}
//! Mark an entry as currently-connected-to.
void Connected(const CService &addr, int64_t nTime = GetAdjustedTime())
{
{
LOCK(cs);
Check();
Connected_(addr, nTime);
Check();
}
}
//! Ensure that bucket placement is always the same for testing purposes.
void MakeDeterministic(){
nKey.SetNull(); //Do not use outside of tests.
}
};
#endif // BITCOIN_ADDRMAN_H