Stochastic address manager. More...

#include <addrman.h>

Public Member Functions
	AddrMan (std::vector< bool > asmap, int32_t consistency_check_ratio)

	~AddrMan ()

template<typename Stream >
void	Serialize (Stream &s_) const

template<typename Stream >
void	Unserialize (Stream &s_)

size_t	size () const
	Return the number of (unique) addresses in all tables.

bool	Add (const std::vector< CAddress > &vAddr, const CNetAddr &source, std::chrono::seconds time_penalty=0s)
	Attempt to add one or more addresses to addrman's new table.

void	Good (const CService &addr, bool test_before_evict=true, NodeSeconds time=Now< NodeSeconds >())
	Mark an entry as accessible, possibly moving it from "new" to "tried".

void	Attempt (const CService &addr, bool fCountFailure, NodeSeconds time=Now< NodeSeconds >())
	Mark an entry as connection attempted to.

void	ResolveCollisions ()
	See if any to-be-evicted tried table entries have been tested and if so resolve the collisions.

std::pair< CAddress, NodeSeconds >	SelectTriedCollision ()
	Randomly select an address in the tried table that another address is attempting to evict.

std::pair< CAddress, NodeSeconds >	Select (bool newOnly=false) const
	Choose an address to connect to.

std::vector< CAddress >	GetAddr (size_t max_addresses, size_t max_pct, std::optional< Network > network) const
	Return all or many randomly selected addresses, optionally by network.

void	Connected (const CService &addr, NodeSeconds time=Now< NodeSeconds >())
	We have successfully connected to this peer.

void	SetServices (const CService &addr, ServiceFlags nServices)
	Update an entry's service bits.

const std::vector< bool > &	GetAsmap () const

void	Clear ()

void	MakeDeterministic ()
	Ensure that bucket placement is always the same for testing purposes.

Private Attributes
const std::unique_ptr< AddrManImpl >	m_impl

Friends
class	AddrManTest

class	AddrManCorrupted

Detailed Description

Stochastic address manager.

Design goals:

Keep the address tables in-memory, and asynchronously dump the entire table to peers.dat.
Make sure no (localized) attacker can fill the entire table with his nodes/addresses.

To that end:

Addresses are organized into buckets.
- Addresses that have not yet been tried go into 1024 "new" buckets.
  - Based on the address range (/16 for IPv4) of the source of information, 64 buckets are selected at random.
  - The actual bucket is chosen from one of these, based on the range in which the address itself is located.
  - One single address can occur in up to 8 different buckets to increase selection chances for addresses that are seen frequently. The chance for increasing this multiplicity decreases exponentially.
  - When adding a new address to a full bucket, a randomly chosen entry (with a bias favoring less recently seen ones) is removed from it first.
- Addresses of nodes that are known to be accessible go into 256 "tried" buckets.
  - Each address range selects at random 8 of these buckets.
  - The actual bucket is chosen from one of these, based on the full address.
  - When adding a new good address to a full bucket, a randomly chosen entry (with a bias favoring less recently tried ones) is evicted from it, back to the "new" buckets.
- Bucket selection is based on cryptographic hashing, using a randomly-generated 256-bit key, which should not be observable by adversaries.
- Several indexes are kept for high performance. Setting m_consistency_check_ratio with the -checkaddrman configuration option will introduce (expensive) consistency checks for the entire data structure.

Definition at line 68 of file addrman.h.

Constructor & Destructor Documentation

◆ AddrMan()

AddrMan::AddrMan	(	std::vector< bool >	asmap,
		int32_t	consistency_check_ratio
	)

Definition at line 1290 of file addrman.cpp.

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◆ ~AddrMan()

AddrMan::~AddrMan ( )

default

Member Function Documentation

◆ Add()

bool AddrMan::Add	(	const std::vector< CAddress > &	vAddr,
		const CNetAddr &	source,
		std::chrono::seconds	time_penalty = `0s`
	)

Attempt to add one or more addresses to addrman's new table.

Parameters

[in]	vAddr	Address records to attempt to add.
[in]	source	The address of the node that sent us these addr records.
[in]	time_penalty	A "time penalty" to apply to the address record's nTime. If a peer sends us an address record with nTime=n, then we'll add it to our addrman with nTime=(n - time_penalty).

Returns: true if at least one address is successfully added.

Definition at line 1318 of file addrman.cpp.

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◆ Attempt()

void AddrMan::Attempt	(	const CService &	addr,
		bool	fCountFailure,
		NodeSeconds	time = `Now<NodeSeconds>()`
	)

Mark an entry as connection attempted to.

Definition at line 1328 of file addrman.cpp.

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◆ Clear()

void AddrMan::Clear ( )

Definition at line 1362 of file addrman.cpp.

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◆ Connected()

void AddrMan::Connected	(	const CService &	addr,
		NodeSeconds	time = `Now<NodeSeconds>()`
	)

We have successfully connected to this peer.

Calling this function updates the CAddress's nTime, which is used in our IsTerrible() decisions and gossiped to peers. Callers should be careful that updating this information doesn't leak topology information to network spies.

net_processing calls this function when it disconnects from a peer to not leak information about currently connected peers.

Parameters

[in]	addr	The address of the peer we were connected to
[in]	time	The time that we were last connected to this peer

Definition at line 1350 of file addrman.cpp.

◆ GetAddr()

std::vector< CAddress > AddrMan::GetAddr	(	size_t	max_addresses,
		size_t	max_pct,
		std::optional< Network >	network
	)		const

Return all or many randomly selected addresses, optionally by network.

Parameters

[in]	max_addresses	Maximum number of addresses to return (0 = all).
[in]	max_pct	Maximum percentage of addresses to return (0 = all).
[in]	network	Select only addresses of this network (nullopt = all).

Returns: A vector of randomly selected addresses from vRandom.

Definition at line 1345 of file addrman.cpp.

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◆ GetAsmap()

const std::vector< bool > & AddrMan::GetAsmap ( ) const

Definition at line 1358 of file addrman.cpp.

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◆ Good()

void AddrMan::Good	(	const CService &	addr,
		bool	test_before_evict = `true`,
		NodeSeconds	time = `Now<NodeSeconds>()`
	)

Mark an entry as accessible, possibly moving it from "new" to "tried".

Definition at line 1323 of file addrman.cpp.

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◆ MakeDeterministic()

void AddrMan::MakeDeterministic ( )

Ensure that bucket placement is always the same for testing purposes.

Definition at line 1366 of file addrman.cpp.

◆ ResolveCollisions()

void AddrMan::ResolveCollisions ( )

See if any to-be-evicted tried table entries have been tested and if so resolve the collisions.

Definition at line 1333 of file addrman.cpp.

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◆ Select()

std::pair< CAddress, NodeSeconds > AddrMan::Select ( bool newOnly = false ) const

Choose an address to connect to.

Parameters

[in] newOnly Whether to only select addresses from the new table.

Returns: CAddress The record for the selected peer. seconds The last time we attempted to connect to that peer.

Definition at line 1341 of file addrman.cpp.

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◆ SelectTriedCollision()

std::pair< CAddress, NodeSeconds > AddrMan::SelectTriedCollision ( )

Randomly select an address in the tried table that another address is attempting to evict.

Returns: CAddress The record for the selected tried peer. seconds The last time we attempted to connect to that peer.

Definition at line 1337 of file addrman.cpp.

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◆ Serialize()

template<typename Stream >

template void AddrMan::Serialize ( Stream & s_ ) const

Definition at line 1298 of file addrman.cpp.

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◆ SetServices()

void AddrMan::SetServices	(	const CService &	addr,
		ServiceFlags	nServices
	)

Update an entry's service bits.

Definition at line 1354 of file addrman.cpp.

◆ size()

size_t AddrMan::size ( ) const

Return the number of (unique) addresses in all tables.

Definition at line 1314 of file addrman.cpp.

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◆ Unserialize()

template<typename Stream >

template void AddrMan::Unserialize ( Stream & s_ )

Definition at line 1302 of file addrman.cpp.

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Friends And Related Symbol Documentation

◆ AddrManCorrupted

friend class AddrManCorrupted

friend

Definition at line 168 of file addrman.h.

◆ AddrManTest

friend class AddrManTest

friend

Definition at line 167 of file addrman.h.

Member Data Documentation

◆ m_impl

const std::unique_ptr<AddrManImpl> AddrMan::m_impl

private

Definition at line 69 of file addrman.h.

The documentation for this class was generated from the following files:

src/addrman.h
src/addrman.cpp

Public Member Functions

Private Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ AddrMan()

◆ ~AddrMan()

Member Function Documentation

◆ Add()

◆ Attempt()

◆ Clear()

◆ Connected()

◆ GetAddr()

◆ GetAsmap()

◆ Good()

◆ MakeDeterministic()

◆ ResolveCollisions()

◆ Select()

◆ SelectTriedCollision()

◆ Serialize()

◆ SetServices()

◆ size()

◆ Unserialize()

Friends And Related Symbol Documentation

◆ AddrManCorrupted

◆ AddrManTest

Member Data Documentation

◆ m_impl