/root/bitcoin/src/netgroup.h
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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 | | class NetGroupManager { |
18 | | public: |
19 | | NetGroupManager(const NetGroupManager&) = delete; |
20 | 0 | NetGroupManager(NetGroupManager&&) = default; |
21 | | NetGroupManager& operator=(const NetGroupManager&) = delete; |
22 | | NetGroupManager& operator=(NetGroupManager&&) = delete; |
23 | | |
24 | 0 | static NetGroupManager WithEmbeddedAsmap(std::span<const std::byte> asmap) { |
25 | 0 | return NetGroupManager(asmap, {}); |
26 | 0 | } |
27 | | |
28 | 0 | static NetGroupManager WithLoadedAsmap(std::vector<std::byte>&& asmap) { |
29 | 0 | return NetGroupManager(std::span{asmap}, std::move(asmap)); |
30 | 0 | } |
31 | | |
32 | 0 | static NetGroupManager NoAsmap() { |
33 | 0 | return NetGroupManager({}, {}); |
34 | 0 | } |
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 | | explicit NetGroupManager(std::span<const std::byte> embedded_asmap, std::vector<std::byte>&& loaded_asmap) |
97 | 0 | : m_asmap{embedded_asmap}, |
98 | 0 | m_loaded_asmap{std::move(loaded_asmap)} |
99 | 0 | { |
100 | | assert(m_loaded_asmap.empty() || m_asmap.data() == m_loaded_asmap.data()); |
101 | 0 | } |
102 | | }; |
103 | | |
104 | | #endif // BITCOIN_NETGROUP_H |