Branch data     Line data    Source code

       1                 :             : // Copyright (c) 2021-present 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 <cstddef>
      12                 :             : #include <vector>
      13                 :             : 
      14                 :             : /**
      15                 :             :  * Netgroup manager
      16                 :             :  */
      17   [ +  -  +  - ]:        2547 : class NetGroupManager {
                 [ +  - ]
      18                 :             : public:
      19                 :             :     NetGroupManager(const NetGroupManager&) = delete;
      20                 :        1271 :     NetGroupManager(NetGroupManager&&) = default;
      21                 :             :     NetGroupManager& operator=(const NetGroupManager&) = delete;
      22                 :             :     NetGroupManager& operator=(NetGroupManager&&) = delete;
      23                 :             : 
      24                 :           4 :     static NetGroupManager WithEmbeddedAsmap(std::span<const std::byte> asmap) {
      25                 :           4 :         return NetGroupManager(asmap, {});
      26                 :             :     }
      27                 :             : 
      28                 :           5 :     static NetGroupManager WithLoadedAsmap(std::vector<std::byte>&& asmap) {
      29         [ -  + ]:           5 :         return NetGroupManager(std::span{asmap}, std::move(asmap));
      30                 :             :     }
      31                 :             : 
      32                 :        1414 :     static NetGroupManager NoAsmap() {
      33                 :        1414 :         return NetGroupManager({}, {});
      34                 :             :     }
      35                 :             : 
      36                 :             :     /** Get the asmap version, a checksum identifying the asmap being used. */
      37                 :             :     uint256 GetAsmapVersion() const;
      38                 :             : 
      39                 :             :     /**
      40                 :             :      * Get the canonical identifier of the network group for address.
      41                 :             :      *
      42                 :             :      * The groups are assigned in a way where it should be costly for an attacker to
      43                 :             :      * obtain addresses with many different group identifiers, even if it is cheap
      44                 :             :      * to obtain addresses with the same identifier.
      45                 :             :      *
      46                 :             :      * @note No two connections will be attempted to addresses with the same network
      47                 :             :      *       group.
      48                 :             :      */
      49                 :             :     std::vector<unsigned char> GetGroup(const CNetAddr& address) const;
      50                 :             : 
      51                 :             :     /**
      52                 :             :      *  Get the autonomous system on the BGP path to address.
      53                 :             :      *
      54                 :             :      *  The ip->AS mapping depends on how asmap is constructed.
      55                 :             :      */
      56                 :             :     uint32_t GetMappedAS(const CNetAddr& address) const;
      57                 :             : 
      58                 :             :     /**
      59                 :             :      *  Analyze and log current health of ASMap based buckets.
      60                 :             :      */
      61                 :             :     void ASMapHealthCheck(const std::vector<CNetAddr>& clearnet_addrs) const;
      62                 :             : 
      63                 :             :     /**
      64                 :             :      *  Indicates whether ASMap is being used for clearnet bucketing.
      65                 :             :      */
      66                 :             :     bool UsingASMap() const;
      67                 :             : 
      68                 :             : private:
      69                 :             :     /** Compressed IP->ASN mapping.
      70                 :             :      *
      71                 :             :      * Data may be loaded from a file when a node starts or embedded in the
      72                 :             :      * binary.
      73                 :             :      *
      74                 :             :      * This mapping is then used for bucketing nodes in Addrman and for
      75                 :             :      * ensuring we connect to a diverse set of peers in Connman. The map is
      76                 :             :      * empty if no file was provided.
      77                 :             :      *
      78                 :             :      * If asmap is provided, nodes will be bucketed by AS they belong to, in
      79                 :             :      * order to make impossible for a node to connect to several nodes hosted
      80                 :             :      * in a single AS. This is done in response to Erebus attack, but also to
      81                 :             :      * generally diversify the connections every node creates, especially
      82                 :             :      * useful when a large fraction of nodes operate under a couple of cloud
      83                 :             :      * providers.
      84                 :             :      *
      85                 :             :      * If a new asmap is provided, the existing addrman records are
      86                 :             :      * re-bucketed.
      87                 :             :      *
      88                 :             :      * This is initialized in the constructor, const, and therefore is
      89                 :             :      * thread-safe. m_asmap can either point to m_loaded_asmap which holds
      90                 :             :      * data loaded from an external file at runtime or it can point to embedded
      91                 :             :      * asmap data.
      92                 :             :      */
      93                 :             :     const std::span<const std::byte> m_asmap;
      94                 :             :     std::vector<std::byte> m_loaded_asmap;
      95                 :             : 
      96                 :        1423 :     explicit NetGroupManager(std::span<const std::byte> embedded_asmap, std::vector<std::byte>&& loaded_asmap)
      97                 :        1423 :         : m_asmap{embedded_asmap},
      98         [ +  + ]:        1423 :           m_loaded_asmap{std::move(loaded_asmap)}
      99                 :             :     {
     100   [ +  +  -  + ]:        1423 :         assert(m_loaded_asmap.empty() || m_asmap.data() == m_loaded_asmap.data());
     101                 :        1423 :     }
     102                 :             : };
     103                 :             : 
     104                 :             : #endif // BITCOIN_NETGROUP_H