[addrman] Introduce CAddrMan::Impl to encapsulate addrman implementation.

Introduce the pimpl pattern for CAddrMan to separate the implementation details
from the externally used object representation. This reduces compile-time
dependencies and conceptually clarifies AddrMan's interface from the
implementation specifics.

Since the unit & fuzz tests currently rely on accessing CAddrMan internals, this
commit introduces addrman_impl.h, which is exclusively imported by addrman.cpp
and test files.

Review hint: git diff --color-moved=dimmed-zebra
--color-moved-ws=ignore-all-space

1 files changed, 17 insertions, 171 deletions

diff --git a/src/addrman.h b/src/addrman.h
index d3d764c9c6..2135295b89 100644
--- a/src/addrman.h
+++ b/src/addrman.h
@@ -19,6 +19,8 @@
 #include <unordered_map>
 #include <vector>
 
+class AddrManImpl;
+
 /** Default for -checkaddrman */
 static constexpr int32_t DEFAULT_ADDRMAN_CONSISTENCY_CHECKS{0};
 
@@ -53,7 +55,7 @@ private:
     //! position in vRandom
     mutable int nRandomPos{-1};
 
-    friend class CAddrMan;
+    friend class AddrManImpl;
     friend class CAddrManDeterministic;
 
 public:
@@ -141,42 +143,41 @@ static constexpr int ADDRMAN_BUCKET_SIZE{1 << ADDRMAN_BUCKET_SIZE_LOG2};
  */
 class CAddrMan
 {
+    const std::unique_ptr<AddrManImpl> m_impl;
+
 public:
     explicit CAddrMan(std::vector<bool> asmap, bool deterministic, int32_t consistency_check_ratio);
 
     ~CAddrMan();
 
     template <typename Stream>
-    void Serialize(Stream& s_) const EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    void Serialize(Stream& s_) const;
 
     template <typename Stream>
-    void Unserialize(Stream& s_) EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    void Unserialize(Stream& s_);
 
     //! Return the number of (unique) addresses in all tables.
-    size_t size() const EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    size_t size() const;
 
     //! Add addresses to addrman's new table.
-    bool Add(const std::vector<CAddress> &vAddr, const CNetAddr& source, int64_t nTimePenalty = 0)
-        EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    bool Add(const std::vector<CAddress> &vAddr, const CNetAddr& source, int64_t nTimePenalty = 0);
 
     //! Mark an entry as accessible.
-    void Good(const CService &addr, int64_t nTime = GetAdjustedTime())
-        EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    void Good(const CService &addr, int64_t nTime = GetAdjustedTime());
 
     //! Mark an entry as connection attempted to.
-    void Attempt(const CService &addr, bool fCountFailure, int64_t nTime = GetAdjustedTime())
-        EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    void Attempt(const CService &addr, bool fCountFailure, int64_t nTime = GetAdjustedTime());
 
     //! See if any to-be-evicted tried table entries have been tested and if so resolve the collisions.
-    void ResolveCollisions() EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    void ResolveCollisions();
 
     //! Randomly select an address in tried that another address is attempting to evict.
-    CAddrInfo SelectTriedCollision() EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    CAddrInfo SelectTriedCollision();
 
     /**
      * Choose an address to connect to.
      */
-    CAddrInfo Select(bool newOnly = false) const EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    CAddrInfo Select(bool newOnly = false) const;
 
     /**
      * Return all or many randomly selected addresses, optionally by network.
@@ -185,170 +186,15 @@ public:
      * @param[in] max_pct        Maximum percentage of addresses to return (0 = all).
      * @param[in] network        Select only addresses of this network (nullopt = all).
      */
-    std::vector<CAddress> GetAddr(size_t max_addresses, size_t max_pct, std::optional<Network> network) const
-        EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    std::vector<CAddress> GetAddr(size_t max_addresses, size_t max_pct, std::optional<Network> network) const;
 
     //! Outer function for Connected_()
-    void Connected(const CService &addr, int64_t nTime = GetAdjustedTime())
-        EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    void Connected(const CService &addr, int64_t nTime = GetAdjustedTime());
 
-    void SetServices(const CService &addr, ServiceFlags nServices)
-        EXCLUSIVE_LOCKS_REQUIRED(!cs);
+    void SetServices(const CService &addr, ServiceFlags nServices);
 
     const std::vector<bool>& GetAsmap() const;
 
-private:
-    //! A mutex to protect the inner data structures.
-    mutable Mutex cs;
-
-    //! Source of random numbers for randomization in inner loops
-    mutable FastRandomContext insecure_rand GUARDED_BY(cs);
-
-    //! secret key to randomize bucket select with
-    uint256 nKey;
-
-    //! Serialization versions.
-    enum Format : uint8_t {
-        V0_HISTORICAL = 0,    //!< historic format, before commit e6b343d88
-        V1_DETERMINISTIC = 1, //!< for pre-asmap files
-        V2_ASMAP = 2,         //!< for files including asmap version
-        V3_BIP155 = 3,        //!< same as V2_ASMAP plus addresses are in BIP155 format
-    };
-
-    //! The maximum format this software knows it can unserialize. Also, we always serialize
-    //! in this format.
-    //! The format (first byte in the serialized stream) can be higher than this and
-    //! still this software may be able to unserialize the file - if the second byte
-    //! (see `lowest_compatible` in `Unserialize()`) is less or equal to this.
-    static constexpr Format FILE_FORMAT = Format::V3_BIP155;
-
-    //! The initial value of a field that is incremented every time an incompatible format
-    //! change is made (such that old software versions would not be able to parse and
-    //! understand the new file format). This is 32 because we overtook the "key size"
-    //! field which was 32 historically.
-    //! @note Don't increment this. Increment `lowest_compatible` in `Serialize()` instead.
-    static constexpr uint8_t INCOMPATIBILITY_BASE = 32;
-
-    //! last used nId
-    int nIdCount GUARDED_BY(cs){0};
-
-    //! table with information about all nIds
-    std::unordered_map<int, CAddrInfo> mapInfo GUARDED_BY(cs);
-
-    //! find an nId based on its network address
-    std::unordered_map<CNetAddr, int, CNetAddrHash> mapAddr GUARDED_BY(cs);
-
-    //! randomly-ordered vector of all nIds
-    //! This is mutable because it is unobservable outside the class, so any
-    //! changes to it (even in const methods) are also unobservable.
-    mutable std::vector<int> vRandom GUARDED_BY(cs);
-
-    // number of "tried" entries
-    int nTried GUARDED_BY(cs){0};
-
-    //! list of "tried" buckets
-    int vvTried[ADDRMAN_TRIED_BUCKET_COUNT][ADDRMAN_BUCKET_SIZE] GUARDED_BY(cs);
-
-    //! number of (unique) "new" entries
-    int nNew GUARDED_BY(cs){0};
-
-    //! list of "new" buckets
-    int vvNew[ADDRMAN_NEW_BUCKET_COUNT][ADDRMAN_BUCKET_SIZE] GUARDED_BY(cs);
-
-    //! last time Good was called (memory only). Initially set to 1 so that "never" is strictly worse.
-    int64_t nLastGood GUARDED_BY(cs){1};
-
-    //! Holds addrs inserted into tried table that collide with existing entries. Test-before-evict discipline used to resolve these collisions.
-    std::set<int> m_tried_collisions;
-
-    /** Perform consistency checks every m_consistency_check_ratio operations (if non-zero). */
-    const int32_t m_consistency_check_ratio;
-
-    // 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.
-    const std::vector<bool> m_asmap;
-
-    //! Find an entry.
-    CAddrInfo* Find(const CNetAddr& addr, int *pnId = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Create a new entry and add it to the internal data structures mapInfo, mapAddr and vRandom.
-    CAddrInfo* Create(const CAddress &addr, const CNetAddr &addrSource, int *pnId = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Swap two elements in vRandom.
-    void SwapRandom(unsigned int nRandomPos1, unsigned int nRandomPos2) const EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Delete an entry. It must not be in tried, and have refcount 0.
-    void Delete(int nId) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Clear a position in a "new" table. This is the only place where entries are actually deleted.
-    void ClearNew(int nUBucket, int nUBucketPos) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Move an entry from the "new" table(s) to the "tried" table
-    void MakeTried(CAddrInfo& info, int nId) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Mark an entry "good", possibly moving it from "new" to "tried".
-    void Good_(const CService &addr, bool test_before_evict, int64_t time) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Add an entry to the "new" table.
-    bool Add_(const CAddress &addr, const CNetAddr& source, int64_t nTimePenalty) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Mark an entry as attempted to connect.
-    void Attempt_(const CService &addr, bool fCountFailure, int64_t nTime) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Select an address to connect to, if newOnly is set to true, only the new table is selected from.
-    CAddrInfo Select_(bool newOnly) const EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    /**
-     * Return all or many randomly selected addresses, optionally by network.
-     *
-     * @param[out] vAddr         Vector of randomly selected addresses from vRandom.
-     * @param[in] max_addresses  Maximum number of addresses to return (0 = all).
-     * @param[in] max_pct        Maximum percentage of addresses to return (0 = all).
-     * @param[in] network        Select only addresses of this network (nullopt = all).
-     */
-    void GetAddr_(std::vector<CAddress>& vAddr, size_t max_addresses, size_t max_pct, std::optional<Network> network) const EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    /** We have successfully connected to this peer. Calling this function
-     *  updates the CAddress's nTime, which is used in our IsTerrible()
-     *  decisions and gossiped to peers. Callers should be careful that updating
-     *  this information doesn't leak topology information to network spies.
-     *
-     *  net_processing calls this function when it *disconnects* from a peer to
-     *  not leak information about currently connected peers.
-     *
-     * @param[in]   addr     The address of the peer we were connected to
-     * @param[in]   nTime    The time that we were last connected to this peer
-     */
-    void Connected_(const CService& addr, int64_t nTime) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Update an entry's service bits.
-    void SetServices_(const CService &addr, ServiceFlags nServices) EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! See if any to-be-evicted tried table entries have been tested and if so resolve the collisions.
-    void ResolveCollisions_() EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Return a random to-be-evicted tried table address.
-    CAddrInfo SelectTriedCollision_() EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Consistency check, taking into account m_consistency_check_ratio. Will std::abort if an inconsistency is detected.
-    void Check() const EXCLUSIVE_LOCKS_REQUIRED(cs);
-
-    //! Perform consistency check, regardless of m_consistency_check_ratio.
-    //! @returns an error code or zero.
-    int ForceCheckAddrman() const EXCLUSIVE_LOCKS_REQUIRED(cs);
-
     friend class CAddrManTest;
     friend class CAddrManDeterministic;
 };