Line data    Source code

       1              : // Copyright (c) 2021 The Bitcoin Core developers
       2              : // Distributed under the MIT software license, see the accompanying
       3              : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4              : 
       5              : #ifndef BITCOIN_NETGROUP_H
       6              : #define BITCOIN_NETGROUP_H
       7              : 
       8              : #include <netaddress.h>
       9              : #include <uint256.h>
      10              : 
      11              : #include <vector>
      12              : 
      13              : /**
      14              :  * Netgroup manager
      15              :  */
      16         1141 : class NetGroupManager {
      17              : public:
      18         1141 :     explicit NetGroupManager(std::vector<bool> asmap)
      19         1141 :         : m_asmap{std::move(asmap)}
      20              :     {}
      21              : 
      22              :     /** Get a checksum identifying the asmap being used. */
      23              :     uint256 GetAsmapChecksum() const;
      24              : 
      25              :     /**
      26              :      * Get the canonical identifier of the network group for address.
      27              :      *
      28              :      * The groups are assigned in a way where it should be costly for an attacker to
      29              :      * obtain addresses with many different group identifiers, even if it is cheap
      30              :      * to obtain addresses with the same identifier.
      31              :      *
      32              :      * @note No two connections will be attempted to addresses with the same network
      33              :      *       group.
      34              :      */
      35              :     std::vector<unsigned char> GetGroup(const CNetAddr& address) const;
      36              : 
      37              :     /**
      38              :      *  Get the autonomous system on the BGP path to address.
      39              :      *
      40              :      *  The ip->AS mapping depends on how asmap is constructed.
      41              :      */
      42              :     uint32_t GetMappedAS(const CNetAddr& address) const;
      43              : 
      44              :     /**
      45              :      *  Analyze and log current health of ASMap based buckets.
      46              :      */
      47              :     void ASMapHealthCheck(const std::vector<CNetAddr>& clearnet_addrs) const;
      48              : 
      49              :     /**
      50              :      *  Indicates whether ASMap is being used for clearnet bucketing.
      51              :      */
      52              :     bool UsingASMap() const;
      53              : 
      54              : private:
      55              :     /** Compressed IP->ASN mapping, loaded from a file when a node starts.
      56              :      *
      57              :      * This mapping is then used for bucketing nodes in Addrman and for
      58              :      * ensuring we connect to a diverse set of peers in Connman. The map is
      59              :      * empty if no file was provided.
      60              :      *
      61              :      * If asmap is provided, nodes will be bucketed by AS they belong to, in
      62              :      * order to make impossible for a node to connect to several nodes hosted
      63              :      * in a single AS. This is done in response to Erebus attack, but also to
      64              :      * generally diversify the connections every node creates, especially
      65              :      * useful when a large fraction of nodes operate under a couple of cloud
      66              :      * providers.
      67              :      *
      68              :      * If a new asmap is provided, the existing addrman records are
      69              :      * re-bucketed.
      70              :      *
      71              :      * This is initialized in the constructor, const, and therefore is
      72              :      * thread-safe. */
      73              :     const std::vector<bool> m_asmap;
      74              : };
      75              : 
      76              : #endif // BITCOIN_NETGROUP_H