/root/bitcoin/src/addrman.h
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1 | | // Copyright (c) 2012 Pieter Wuille |
2 | | // Copyright (c) 2012-present The Bitcoin Core developers |
3 | | // Distributed under the MIT software license, see the accompanying |
4 | | // file COPYING or http://www.opensource.org/licenses/mit-license.php. |
5 | | |
6 | | #ifndef BITCOIN_ADDRMAN_H |
7 | | #define BITCOIN_ADDRMAN_H |
8 | | |
9 | | #include <netaddress.h> |
10 | | #include <netgroup.h> |
11 | | #include <protocol.h> |
12 | | #include <streams.h> |
13 | | #include <util/time.h> |
14 | | |
15 | | #include <cstdint> |
16 | | #include <memory> |
17 | | #include <optional> |
18 | | #include <unordered_set> |
19 | | #include <utility> |
20 | | #include <vector> |
21 | | |
22 | | /** Over how many buckets entries with tried addresses from a single group (/16 for IPv4) are spread */ |
23 | | static constexpr uint32_t ADDRMAN_TRIED_BUCKETS_PER_GROUP{8}; |
24 | | /** Over how many buckets entries with new addresses originating from a single group are spread */ |
25 | | static constexpr uint32_t ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP{64}; |
26 | | /** Maximum number of times an address can occur in the new table */ |
27 | | static constexpr int32_t ADDRMAN_NEW_BUCKETS_PER_ADDRESS{8}; |
28 | | /** How old addresses can maximally be */ |
29 | | static constexpr auto ADDRMAN_HORIZON{30 * 24h}; |
30 | | /** After how many failed attempts we give up on a new node */ |
31 | | static constexpr int32_t ADDRMAN_RETRIES{3}; |
32 | | /** How many successive failures are allowed ... */ |
33 | | static constexpr int32_t ADDRMAN_MAX_FAILURES{10}; |
34 | | /** ... in at least this duration */ |
35 | | static constexpr auto ADDRMAN_MIN_FAIL{7 * 24h}; |
36 | | /** How recent a successful connection should be before we allow an address to be evicted from tried */ |
37 | | static constexpr auto ADDRMAN_REPLACEMENT{4h}; |
38 | | /** The maximum number of tried addr collisions to store */ |
39 | | static constexpr size_t ADDRMAN_SET_TRIED_COLLISION_SIZE{10}; |
40 | | /** The maximum time we'll spend trying to resolve a tried table collision */ |
41 | | static constexpr auto ADDRMAN_TEST_WINDOW{40min}; |
42 | | |
43 | | class InvalidAddrManVersionError : public std::ios_base::failure |
44 | | { |
45 | | public: |
46 | 0 | InvalidAddrManVersionError(std::string msg) : std::ios_base::failure(msg) { } |
47 | | }; |
48 | | |
49 | | class AddrManImpl; |
50 | | class AddrInfo; |
51 | | |
52 | | /** Default for -checkaddrman */ |
53 | | static constexpr int32_t DEFAULT_ADDRMAN_CONSISTENCY_CHECKS{0}; |
54 | | |
55 | | /** Location information for an address in AddrMan */ |
56 | | struct AddressPosition { |
57 | | // Whether the address is in the new or tried table |
58 | | const bool tried; |
59 | | |
60 | | // Addresses in the tried table should always have a multiplicity of 1. |
61 | | // Addresses in the new table can have multiplicity between 1 and |
62 | | // ADDRMAN_NEW_BUCKETS_PER_ADDRESS |
63 | | const int multiplicity; |
64 | | |
65 | | // If the address is in the new table, the bucket and position are |
66 | | // populated based on the first source who sent the address. |
67 | | // In certain edge cases, this may not be where the address is currently |
68 | | // located. |
69 | | const int bucket; |
70 | | const int position; |
71 | | |
72 | 0 | bool operator==(AddressPosition other) { |
73 | 0 | return std::tie(tried, multiplicity, bucket, position) == |
74 | 0 | std::tie(other.tried, other.multiplicity, other.bucket, other.position); |
75 | 0 | } |
76 | | explicit AddressPosition(bool tried_in, int multiplicity_in, int bucket_in, int position_in) |
77 | 0 | : tried{tried_in}, multiplicity{multiplicity_in}, bucket{bucket_in}, position{position_in} {} |
78 | | }; |
79 | | |
80 | | /** Stochastic address manager |
81 | | * |
82 | | * Design goals: |
83 | | * * Keep the address tables in-memory, and asynchronously dump the entire table to peers.dat. |
84 | | * * Make sure no (localized) attacker can fill the entire table with his nodes/addresses. |
85 | | * |
86 | | * To that end: |
87 | | * * Addresses are organized into buckets that can each store up to 64 entries. |
88 | | * * Addresses to which our node has not successfully connected go into 1024 "new" buckets. |
89 | | * * Based on the address range (/16 for IPv4) of the source of information, or if an asmap is provided, |
90 | | * the AS it belongs to (for IPv4/IPv6), 64 buckets are selected at random. |
91 | | * * The actual bucket is chosen from one of these, based on the range in which the address itself is located. |
92 | | * * The position in the bucket is chosen based on the full address. |
93 | | * * One single address can occur in up to 8 different buckets to increase selection chances for addresses that |
94 | | * are seen frequently. The chance for increasing this multiplicity decreases exponentially. |
95 | | * * When adding a new address to an occupied position of a bucket, it will not replace the existing entry |
96 | | * unless that address is also stored in another bucket or it doesn't meet one of several quality criteria |
97 | | * (see IsTerrible for exact criteria). |
98 | | * * Addresses of nodes that are known to be accessible go into 256 "tried" buckets. |
99 | | * * Each address range selects at random 8 of these buckets. |
100 | | * * The actual bucket is chosen from one of these, based on the full address. |
101 | | * * When adding a new good address to an occupied position of a bucket, a FEELER connection to the |
102 | | * old address is attempted. The old entry is only replaced and moved back to the "new" buckets if this |
103 | | * attempt was unsuccessful. |
104 | | * * Bucket selection is based on cryptographic hashing, using a randomly-generated 256-bit key, which should not |
105 | | * be observable by adversaries. |
106 | | * * Several indexes are kept for high performance. Setting m_consistency_check_ratio with the -checkaddrman |
107 | | * configuration option will introduce (expensive) consistency checks for the entire data structure. |
108 | | */ |
109 | | class AddrMan |
110 | | { |
111 | | protected: |
112 | | const std::unique_ptr<AddrManImpl> m_impl; |
113 | | |
114 | | public: |
115 | | explicit AddrMan(const NetGroupManager& netgroupman, bool deterministic, int32_t consistency_check_ratio); |
116 | | |
117 | | ~AddrMan(); |
118 | | |
119 | | template <typename Stream> |
120 | | void Serialize(Stream& s_) const; |
121 | | |
122 | | template <typename Stream> |
123 | | void Unserialize(Stream& s_); |
124 | | |
125 | | /** |
126 | | * Return size information about addrman. |
127 | | * |
128 | | * @param[in] net Select addresses only from specified network (nullopt = all) |
129 | | * @param[in] in_new Select addresses only from one table (true = new, false = tried, nullopt = both) |
130 | | * @return Number of unique addresses that match specified options. |
131 | | */ |
132 | | size_t Size(std::optional<Network> net = std::nullopt, std::optional<bool> in_new = std::nullopt) const; |
133 | | |
134 | | /** |
135 | | * Attempt to add one or more addresses to addrman's new table. |
136 | | * If an address already exists in addrman, the existing entry may be updated |
137 | | * (e.g. adding additional service flags). If the existing entry is in the new table, |
138 | | * it may be added to more buckets, improving the probability of selection. |
139 | | * |
140 | | * @param[in] vAddr Address records to attempt to add. |
141 | | * @param[in] source The address of the node that sent us these addr records. |
142 | | * @param[in] time_penalty A "time penalty" to apply to the address record's nTime. If a peer |
143 | | * sends us an address record with nTime=n, then we'll add it to our |
144 | | * addrman with nTime=(n - time_penalty). |
145 | | * @return true if at least one address is successfully added, or added to an additional bucket. Unaffected by updates. */ |
146 | | bool Add(const std::vector<CAddress>& vAddr, const CNetAddr& source, std::chrono::seconds time_penalty = 0s); |
147 | | |
148 | | /** |
149 | | * Mark an address record as accessible and attempt to move it to addrman's tried table. |
150 | | * |
151 | | * @param[in] addr Address record to attempt to move to tried table. |
152 | | * @param[in] time The time that we were last connected to this peer. |
153 | | * @return true if the address is successfully moved from the new table to the tried table. |
154 | | */ |
155 | | bool Good(const CService& addr, NodeSeconds time = Now<NodeSeconds>()); |
156 | | |
157 | | //! Mark an entry as connection attempted to. |
158 | | void Attempt(const CService& addr, bool fCountFailure, NodeSeconds time = Now<NodeSeconds>()); |
159 | | |
160 | | //! See if any to-be-evicted tried table entries have been tested and if so resolve the collisions. |
161 | | void ResolveCollisions(); |
162 | | |
163 | | /** |
164 | | * Randomly select an address in the tried table that another address is |
165 | | * attempting to evict. |
166 | | * |
167 | | * @return CAddress The record for the selected tried peer. |
168 | | * seconds The last time we attempted to connect to that peer. |
169 | | */ |
170 | | std::pair<CAddress, NodeSeconds> SelectTriedCollision(); |
171 | | |
172 | | /** |
173 | | * Choose an address to connect to. |
174 | | * |
175 | | * @param[in] new_only Whether to only select addresses from the new table. Passing `true` returns |
176 | | * an address from the new table or an empty pair. Passing `false` will return an |
177 | | * empty pair or an address from either the new or tried table (it does not |
178 | | * guarantee a tried entry). |
179 | | * @param[in] networks Select only addresses of these networks (empty = all). Passing networks may |
180 | | * slow down the search. |
181 | | * @return CAddress The record for the selected peer. |
182 | | * seconds The last time we attempted to connect to that peer. |
183 | | */ |
184 | | std::pair<CAddress, NodeSeconds> Select(bool new_only = false, const std::unordered_set<Network>& networks = {}) const; |
185 | | |
186 | | /** |
187 | | * Return all or many randomly selected addresses, optionally by network. |
188 | | * |
189 | | * @param[in] max_addresses Maximum number of addresses to return (0 = all). |
190 | | * @param[in] max_pct Maximum percentage of addresses to return (0 = all). Value must be from 0 to 100. |
191 | | * @param[in] network Select only addresses of this network (nullopt = all). |
192 | | * @param[in] filtered Select only addresses that are considered good quality (false = all). |
193 | | * |
194 | | * @return A vector of randomly selected addresses from vRandom. |
195 | | */ |
196 | | std::vector<CAddress> GetAddr(size_t max_addresses, size_t max_pct, std::optional<Network> network, bool filtered = true) const; |
197 | | |
198 | | /** |
199 | | * Returns an information-location pair for all addresses in the selected addrman table. |
200 | | * If an address appears multiple times in the new table, an information-location pair |
201 | | * is returned for each occurrence. Addresses only ever appear once in the tried table. |
202 | | * |
203 | | * @param[in] from_tried Selects which table to return entries from. |
204 | | * |
205 | | * @return A vector consisting of pairs of AddrInfo and AddressPosition. |
206 | | */ |
207 | | std::vector<std::pair<AddrInfo, AddressPosition>> GetEntries(bool from_tried) const; |
208 | | |
209 | | /** We have successfully connected to this peer. Calling this function |
210 | | * updates the CAddress's nTime, which is used in our IsTerrible() |
211 | | * decisions and gossiped to peers. Callers should be careful that updating |
212 | | * this information doesn't leak topology information to network spies. |
213 | | * |
214 | | * net_processing calls this function when it *disconnects* from a peer to |
215 | | * not leak information about currently connected peers. |
216 | | * |
217 | | * @param[in] addr The address of the peer we were connected to |
218 | | * @param[in] time The time that we were last connected to this peer |
219 | | */ |
220 | | void Connected(const CService& addr, NodeSeconds time = Now<NodeSeconds>()); |
221 | | |
222 | | //! Update an entry's service bits. |
223 | | void SetServices(const CService& addr, ServiceFlags nServices); |
224 | | |
225 | | /** Test-only function |
226 | | * Find the address record in AddrMan and return information about its |
227 | | * position. |
228 | | * @param[in] addr The address record to look up. |
229 | | * @return Information about the address record in AddrMan |
230 | | * or nullopt if address is not found. |
231 | | */ |
232 | | std::optional<AddressPosition> FindAddressEntry(const CAddress& addr); |
233 | | }; |
234 | | |
235 | | #endif // BITCOIN_ADDRMAN_H |