addrman.h

Go to the documentation of this file.

// Copyright (c) 2012 Pieter Wuille
// Copyright (c) 2012-2016 The Bitcoin Core developers
// 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 <clientversion.h>
#include <fs.h>
#include <hash.h>
#include <netaddress.h>
#include <protocol.h>
#include <random.h>
#include <streams.h>
#include <sync.h>
#include <timedata.h>
#include <util/system.h>

#include <cstdint>
#include <iostream>
#include <map>
#include <set>
#include <vector>

class CAddrInfo : public CAddress {
public:
    int64_t nLastTry{0};

    int64_t nLastCountAttempt{0};

private:
    CNetAddr source;

    int64_t nLastSuccess{0};

    int nAttempts{0};

    int nRefCount{0};

    bool fInTried{false};

    int nRandomPos{-1};

    friend class CAddrMan;

public:
    SERIALIZE_METHODS(CAddrInfo, obj) {
        READWRITEAS(CAddress, obj);
        READWRITE(obj.source, obj.nLastSuccess, obj.nAttempts);
    }

    CAddrInfo(const CAddress &addrIn, const CNetAddr &addrSource)
        : CAddress(addrIn), source(addrSource) {}

    CAddrInfo() : CAddress(), source() {}

    int GetTriedBucket(const uint256 &nKey,
                       const std::vector<bool> &asmap) const;

    int GetNewBucket(const uint256 &nKey, const CNetAddr &src,
                     const std::vector<bool> &asmap) const;

    int GetNewBucket(const uint256 &nKey,
                     const std::vector<bool> &asmap) const {
        return GetNewBucket(nKey, source, asmap);
    }

    int GetBucketPosition(const uint256 &nKey, bool fNew, int nBucket) const;

    bool IsTerrible(int64_t nNow = GetAdjustedTime()) const;

    double GetChance(int64_t nNow = GetAdjustedTime()) const;
};

#define ADDRMAN_TRIED_BUCKET_COUNT_LOG2 8

#define ADDRMAN_NEW_BUCKET_COUNT_LOG2 10

#define ADDRMAN_BUCKET_SIZE_LOG2 6

#define ADDRMAN_TRIED_BUCKETS_PER_GROUP 8

#define ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP 64

#define ADDRMAN_NEW_BUCKETS_PER_ADDRESS 8

#define ADDRMAN_HORIZON_DAYS 30

#define ADDRMAN_RETRIES 3

#define ADDRMAN_MAX_FAILURES 10

#define ADDRMAN_MIN_FAIL_DAYS 7

#define ADDRMAN_REPLACEMENT_SECONDS (4 * 60 * 60)

#define ADDRMAN_GETADDR_MAX_PCT 23

#define ADDRMAN_GETADDR_MAX 2500

#define ADDRMAN_TRIED_BUCKET_COUNT (1 << ADDRMAN_TRIED_BUCKET_COUNT_LOG2)
#define ADDRMAN_NEW_BUCKET_COUNT (1 << ADDRMAN_NEW_BUCKET_COUNT_LOG2)
#define ADDRMAN_BUCKET_SIZE (1 << ADDRMAN_BUCKET_SIZE_LOG2)

#define ADDRMAN_SET_TRIED_COLLISION_SIZE 10

static const int64_t ADDRMAN_TEST_WINDOW = 40 * 60;

class CAddrMan {
    friend class CAddrManTest;

protected:
    mutable RecursiveMutex cs;

private:
    int nIdCount GUARDED_BY(cs);

    std::map<int, CAddrInfo> mapInfo GUARDED_BY(cs);

    std::map<CNetAddr, int> mapAddr GUARDED_BY(cs);

    std::vector<int> vRandom GUARDED_BY(cs);

    // number of "tried" entries
    int nTried GUARDED_BY(cs);

    int vvTried[ADDRMAN_TRIED_BUCKET_COUNT][ADDRMAN_BUCKET_SIZE] GUARDED_BY(cs);

    int nNew GUARDED_BY(cs);

    int vvNew[ADDRMAN_NEW_BUCKET_COUNT][ADDRMAN_BUCKET_SIZE] GUARDED_BY(cs);

    int64_t nLastGood GUARDED_BY(cs);

    std::set<int> m_tried_collisions;

protected:
    uint256 nKey;

    FastRandomContext insecure_rand;

    CAddrInfo *Find(const CNetAddr &addr, int *pnId = nullptr)
        EXCLUSIVE_LOCKS_REQUIRED(cs);

    CAddrInfo *Create(const CAddress &addr, const CNetAddr &addrSource,
                      int *pnId = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void SwapRandom(unsigned int nRandomPos1, unsigned int nRandomPos2)
        EXCLUSIVE_LOCKS_REQUIRED(cs);

    void MakeTried(CAddrInfo &info, int nId) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void Delete(int nId) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void ClearNew(int nUBucket, int nUBucketPos) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void Good_(const CService &addr, bool test_before_evict, int64_t time)
        EXCLUSIVE_LOCKS_REQUIRED(cs);

    bool Add_(const CAddress &addr, const CNetAddr &source,
              int64_t nTimePenalty) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void Attempt_(const CService &addr, bool fCountFailure, int64_t nTime)
        EXCLUSIVE_LOCKS_REQUIRED(cs);

    CAddrInfo Select_(bool newOnly) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void ResolveCollisions_() EXCLUSIVE_LOCKS_REQUIRED(cs);

    CAddrInfo SelectTriedCollision_() EXCLUSIVE_LOCKS_REQUIRED(cs);

#ifdef DEBUG_ADDRMAN
    int Check_() EXCLUSIVE_LOCKS_REQUIRED(cs);
#endif

    void GetAddr_(std::vector<CAddress> &vAddr) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void Connected_(const CService &addr, int64_t nTime)
        EXCLUSIVE_LOCKS_REQUIRED(cs);

    void SetServices_(const CService &addr, ServiceFlags nServices)
        EXCLUSIVE_LOCKS_REQUIRED(cs);

public:
    // Compressed IP->ASN mapping, loaded from a file when a node starts.
    // Should be always empty if no file was provided.
    // This mapping is then used for bucketing nodes in Addrman.
    //
    // If asmap is provided, nodes will be bucketed by
    // AS they belong to, in order to make impossible for a node
    // to connect to several nodes hosted in a single AS.
    // This is done in response to Erebus attack, but also to generally
    // diversify the connections every node creates,
    // especially useful when a large fraction of nodes
    // operate under a couple of cloud providers.
    //
    // If a new asmap was provided, the existing records
    // would be re-bucketed accordingly.
    std::vector<bool> m_asmap;

    // Read asmap from provided binary file
    static std::vector<bool> DecodeAsmap(fs::path path);

    template <typename Stream> void Serialize(Stream &s) const {
        LOCK(cs);

        uint8_t nVersion = 2;
        s << nVersion;
        s << uint8_t(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 (const auto &entry : mapInfo) {
            mapUnkIds[entry.first] = nIds;
            const CAddrInfo &info = entry.second;
            if (info.nRefCount) {
                // this means nNew was wrong, oh ow
                assert(nIds != nNew);
                s << info;
                nIds++;
            }
        }
        nIds = 0;
        for (const auto &entry : mapInfo) {
            const CAddrInfo &info = entry.second;
            if (info.fInTried) {
                // this means nTried was wrong, oh ow
                assert(nIds != nTried);
                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;
                }
            }
        }
        // Store asmap version after bucket entries so that it
        // can be ignored by older clients for backward compatibility.
        uint256 asmap_version;
        if (m_asmap.size() != 0) {
            asmap_version = SerializeHash(m_asmap);
        }
        s << asmap_version;
    }

    template <typename Stream> void Unserialize(Stream &s) {
        LOCK(cs);

        Clear();
        uint8_t nVersion;
        s >> nVersion;
        uint8_t 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);
        }

        if (nNew > ADDRMAN_NEW_BUCKET_COUNT * ADDRMAN_BUCKET_SIZE) {
            throw std::ios_base::failure(
                "Corrupt CAddrMan serialization, nNew exceeds limit.");
        }

        if (nTried > ADDRMAN_TRIED_BUCKET_COUNT * ADDRMAN_BUCKET_SIZE) {
            throw std::ios_base::failure(
                "Corrupt CAddrMan serialization, nTried exceeds limit.");
        }

        // 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);
        }
        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, m_asmap);
            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;

        // Store positions in the new table buckets to apply later (if
        // possible). Represents which entry belonged to which bucket when
        // serializing
        std::map<int, int> entryToBucket;

        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) {
                    entryToBucket[nIndex] = bucket;
                }
            }
        }

        uint256 supplied_asmap_version;
        if (m_asmap.size() != 0) {
            supplied_asmap_version = SerializeHash(m_asmap);
        }
        uint256 serialized_asmap_version;
        if (nVersion > 1) {
            s >> serialized_asmap_version;
        }

        for (int n = 0; n < nNew; n++) {
            CAddrInfo &info = mapInfo[n];
            int bucket = entryToBucket[n];
            int nUBucketPos = info.GetBucketPosition(nKey, true, bucket);
            if (nVersion == 2 && nUBuckets == ADDRMAN_NEW_BUCKET_COUNT &&
                vvNew[bucket][nUBucketPos] == -1 &&
                info.nRefCount < ADDRMAN_NEW_BUCKETS_PER_ADDRESS &&
                serialized_asmap_version == supplied_asmap_version) {
                // Bucketing has not changed, using existing bucket positions
                // for the new table
                vvNew[bucket][nUBucketPos] = n;
                info.nRefCount++;
            } else {
                // In case the new table data cannot be used (nVersion unknown,
                // bucket count wrong or new asmap), try to give them a
                // reference based on their primary source address.
                LogPrint(BCLog::ADDRMAN,
                         "Bucketing method was updated, re-bucketing addrman "
                         "entries from disk\n");
                bucket = info.GetNewBucket(nKey, m_asmap);
                nUBucketPos = info.GetBucketPosition(nKey, true, bucket);
                if (vvNew[bucket][nUBucketPos] == -1) {
                    vvNew[bucket][nUBucketPos] = n;
                    info.nRefCount++;
                }
            }
        }

        // 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(BCLog::ADDRMAN,
                     "addrman lost %i new and %i tried addresses due to "
                     "collisions\n",
                     nLostUnk, nLost);
        }

        Check();
    }

    void Clear() {
        LOCK(cs);
        std::vector<int>().swap(vRandom);
        nKey = insecure_rand.rand256();
        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;
        // Initially at 1 so that "never" is strictly worse.
        nLastGood = 1;
        mapInfo.clear();
        mapAddr.clear();
    }

    CAddrMan() { Clear(); }

    ~CAddrMan() { nKey.SetNull(); }

    size_t size() const {
        // TODO: Cache this in an atomic to avoid this overhead
        LOCK(cs);
        return vRandom.size();
    }

    void Check() {
#ifdef DEBUG_ADDRMAN
        {
            LOCK(cs);
            int err;
            if ((err = Check_())) {
                LogPrintf("ADDRMAN CONSISTENCY CHECK FAILED!!! err=%i\n", err);
            }
        }
#endif
    }

    bool Add(const CAddress &addr, const CNetAddr &source,
             int64_t nTimePenalty = 0) {
        LOCK(cs);
        bool fRet = false;
        Check();
        fRet |= Add_(addr, source, nTimePenalty);
        Check();
        if (fRet) {
            LogPrint(BCLog::ADDRMAN, "Added %s from %s: %i tried, %i new\n",
                     addr.ToStringIPPort(), source.ToString(), nTried, nNew);
        }
        return fRet;
    }

    bool Add(const std::vector<CAddress> &vAddr, const CNetAddr &source,
             int64_t nTimePenalty = 0) {
        LOCK(cs);
        int nAdd = 0;
        Check();
        for (const CAddress &a : vAddr) {
            nAdd += Add_(a, source, nTimePenalty) ? 1 : 0;
        }
        Check();
        if (nAdd) {
            LogPrint(BCLog::ADDRMAN,
                     "Added %i addresses from %s: %i tried, %i new\n", nAdd,
                     source.ToString(), nTried, nNew);
        }
        return nAdd > 0;
    }

    void Good(const CService &addr, bool test_before_evict = true,
              int64_t nTime = GetAdjustedTime()) {
        LOCK(cs);
        Check();
        Good_(addr, test_before_evict, nTime);
        Check();
    }

    void Attempt(const CService &addr, bool fCountFailure,
                 int64_t nTime = GetAdjustedTime()) {
        LOCK(cs);
        Check();
        Attempt_(addr, fCountFailure, nTime);
        Check();
    }

    void ResolveCollisions() {
        LOCK(cs);
        Check();
        ResolveCollisions_();
        Check();
    }

    CAddrInfo SelectTriedCollision() {
        CAddrInfo ret;
        {
            LOCK(cs);
            Check();
            ret = SelectTriedCollision_();
            Check();
        }
        return ret;
    }

    CAddrInfo Select(bool newOnly = false) {
        CAddrInfo addrRet;
        {
            LOCK(cs);
            Check();
            addrRet = Select_(newOnly);
            Check();
        }
        return addrRet;
    }

    std::vector<CAddress> GetAddr() {
        Check();
        std::vector<CAddress> vAddr;
        {
            LOCK(cs);
            GetAddr_(vAddr);
        }
        Check();
        return vAddr;
    }

    void Connected(const CService &addr, int64_t nTime = GetAdjustedTime()) {
        LOCK(cs);
        Check();
        Connected_(addr, nTime);
        Check();
    }

    void SetServices(const CService &addr, ServiceFlags nServices) {
        LOCK(cs);
        Check();
        SetServices_(addr, nServices);
        Check();
    }
};

#endif // BITCOIN_ADDRMAN_H