Bitcoin ABC  0.26.3
P2P Digital Currency
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1 // Copyright (c) 2009-2010 Satoshi Nakamoto
2 // Copyright (c) 2009-2017 The Bitcoin Core developers
3 // Distributed under the MIT software license, see the accompanying
4 // file COPYING or
8 #include <addrdb.h>
9 #include <common/bloom.h>
10 #include <net_types.h> // For banmap_t
11 #include <sync.h>
12 #include <util/fs.h>
14 #include <chrono>
15 #include <cstdint>
16 #include <memory>
18 // Default 24-hour ban.
19 // NOTE: When adjusting this, update rpcnet:setban's help ("24h")
20 static constexpr unsigned int DEFAULT_MISBEHAVING_BANTIME = 60 * 60 * 24;
21 // How often to dump addresses to banlist.dat
22 static constexpr std::chrono::minutes DUMP_BANS_INTERVAL{15};
24 class CClientUIInterface;
25 class CNetAddr;
26 class CSubNet;
28 // Banman manages two related but distinct concepts:
29 //
30 // 1. Banning. This is configured manually by the user, through the setban RPC.
31 // If an address or subnet is banned, we never accept incoming connections from
32 // it and never create outgoing connections to it. We won't gossip its address
33 // to other peers in addr messages. Banned addresses and subnets are stored to
34 // banlist.dat on shutdown and reloaded on startup. Banning can be used to
35 // prevent connections with spy nodes or other griefers.
36 //
37 // 2. Discouragement. If a peer misbehaves enough (see Misbehaving() in
38 // net_processing.cpp), we'll mark that address as discouraged. We still allow
39 // incoming connections from them, but they're preferred for eviction when
40 // we receive new incoming connections. We never make outgoing connections to
41 // them, and do not gossip their address to other peers. This is implemented as
42 // a bloom filter. We can (probabilistically) test for membership, but can't
43 // list all discouraged addresses or unmark them as discouraged. Discouragement
44 // can prevent our limited connection slots being used up by incompatible
45 // or broken peers.
46 //
47 // Neither banning nor discouragement are protections against denial-of-service
48 // attacks, since if an attacker has a way to waste our resources and we
49 // disconnect from them and ban that address, it's trivial for them to
50 // reconnect from another IP address.
51 //
52 // Attempting to automatically disconnect or ban any class of peer carries the
53 // risk of splitting the network. For example, if we banned/disconnected for a
54 // transaction that fails a policy check and a future version changes the
55 // policy check so the transaction is accepted, then that transaction could
56 // cause the network to split between old nodes and new nodes.
58 class BanMan {
59 public:
60  ~BanMan();
61  BanMan(fs::path ban_file, const CChainParams &chainparams,
62  CClientUIInterface *client_interface, int64_t default_ban_time);
63  void Ban(const CNetAddr &net_addr, int64_t ban_time_offset = 0,
64  bool since_unix_epoch = false);
65  void Ban(const CSubNet &sub_net, int64_t ban_time_offset = 0,
66  bool since_unix_epoch = false);
67  void Discourage(const CNetAddr &net_addr);
68  void ClearBanned();
71  bool IsBanned(const CNetAddr &net_addr);
74  bool IsBanned(const CSubNet &sub_net);
77  bool IsDiscouraged(const CNetAddr &net_addr);
79  bool Unban(const CNetAddr &net_addr);
80  bool Unban(const CSubNet &sub_net);
81  void GetBanned(banmap_t &banmap);
82  void DumpBanlist();
84 private:
85  void SetBanned(const banmap_t &banmap);
86  bool BannedSetIsDirty();
88  void SetBannedSetDirty(bool dirty = true);
90  void SweepBanned();
94  bool m_is_dirty GUARDED_BY(m_cs_banned);
97  const int64_t m_default_ban_time;
98  CRollingBloomFilter m_discouraged GUARDED_BY(m_cs_banned){50000, 0.000001};
99 };
101 #endif // BITCOIN_BANMAN_H
static constexpr unsigned int DEFAULT_MISBEHAVING_BANTIME
Definition: banman.h:20
static constexpr std::chrono::minutes DUMP_BANS_INTERVAL
Definition: banman.h:22
Definition: banman.h:58
void Discourage(const CNetAddr &net_addr)
Definition: banman.cpp:122
void Ban(const CNetAddr &net_addr, int64_t ban_time_offset=0, bool since_unix_epoch=false)
Definition: banman.cpp:116
banmap_t m_banned GUARDED_BY(m_cs_banned)
const int64_t m_default_ban_time
Definition: banman.h:97
void GetBanned(banmap_t &banmap)
Definition: banman.cpp:179
void ClearBanned()
Definition: banman.cpp:70
bool IsBanned(const CNetAddr &net_addr)
Return whether net_addr is banned.
Definition: banman.cpp:89
RecursiveMutex m_cs_banned
Definition: banman.h:92
void SetBanned(const banmap_t &banmap)
Definition: banman.cpp:187
bool BannedSetIsDirty()
Definition: banman.cpp:221
CClientUIInterface * m_client_interface
Definition: banman.h:95
bool Unban(const CNetAddr &net_addr)
Definition: banman.cpp:157
BanMan(fs::path ban_file, const CChainParams &chainparams, CClientUIInterface *client_interface, int64_t default_ban_time)
Definition: banman.cpp:14
CBanDB m_ban_db
Definition: banman.h:96
CRollingBloomFilter m_discouraged GUARDED_BY(m_cs_banned)
Definition: banman.h:98
bool m_is_dirty GUARDED_BY(m_cs_banned)
void SetBannedSetDirty(bool dirty=true)
set the "dirty" flag for the banlist
Definition: banman.cpp:226
Definition: banman.cpp:45
void SweepBanned()
clean unused entries (if bantime has expired)
Definition: banman.cpp:193
void DumpBanlist()
Definition: banman.cpp:49
bool IsDiscouraged(const CNetAddr &net_addr)
Return whether net_addr is discouraged.
Definition: banman.cpp:84
Access to the banlist database (banlist.dat)
Definition: addrdb.h:58
CChainParams defines various tweakable parameters of a given instance of the Bitcoin system.
Definition: chainparams.h:80
Signals for UI communication.
Definition: ui_interface.h:24
Network address.
Definition: netaddress.h:121
RollingBloomFilter is a probabilistic "keep track of most recently inserted" set.
Definition: bloom.h:115
Path class wrapper to block calls to the fs::path(std::string) implicit constructor and the fs::path:...
Definition: fs.h:30
std::map< CSubNet, CBanEntry > banmap_t
Definition: net_types.h:13