Stochastic address manager. More...

#include <addrman.h>

Inheritance diagram for AddrMan:

Public Member Functions
	AddrMan (std::vector< bool > asmap, bool deterministic, 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. More...

bool	Add (const std::vector< CAddress > &vAddr, const CNetAddr &source, int64_t nTimePenalty=0)
	Attempt to add one or more addresses to addrman's new table. More...

bool	Good (const CService &addr, int64_t nTime=GetAdjustedTime())
	Mark an address record as accessible and attempt to move it to addrman's tried table. More...

void	Attempt (const CService &addr, bool fCountFailure, int64_t nTime=GetAdjustedTime())
	Mark an entry as connection attempted to. More...

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

std::pair< CAddress, int64_t >	SelectTriedCollision ()
	Randomly select an address in the tried table that another address is attempting to evict. More...

std::pair< CAddress, int64_t >	Select (bool newOnly=false) const
	Choose an address to connect to. More...

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. More...

void	Connected (const CService &addr, int64_t nTime=GetAdjustedTime())
	We have successfully connected to this peer. More...

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

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

std::optional< AddressPosition >	FindAddressEntry (const CAddress &addr)
	Test-only function Find the address record in AddrMan and return information about its position. More...

Protected Attributes
const std::unique_ptr< AddrManImpl >	m_impl

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 that can each store up to 64 entries.
- Addresses to which our node has not successfully connected go into 1024 "new" buckets.
  - Based on the address range (/16 for IPv4) of the source of information, or if an asmap is provided, the AS it belongs to (for IPv4/IPv6), 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.
  - The position in the bucket is chosen based on the full address.
  - 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 an occupied position of a bucket, it will not replace the existing entry unless that address is also stored in another bucket or it doesn't meet one of several quality criteria (see IsTerrible for exact criteria).
- 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 an occupied position of a bucket, a FEELER connection to the old address is attempted. The old entry is only replaced and moved back to the "new" buckets if this attempt was unsuccessful.
- 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 79 of file addrman.h.

Constructor & Destructor Documentation

◆ AddrMan()

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

explicit

Definition at line 1156 of file addrman.cpp.

◆ ~AddrMan()

AddrMan::~AddrMan ( )

default

Member Function Documentation

◆ Add()

bool AddrMan::Add	(	const std::vector< CAddress > &	vAddr,
		const CNetAddr &	source,
		int64_t	nTimePenalty = `0`
	)

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]	nTimePenalty	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 - nTimePenalty).

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

Definition at line 1187 of file addrman.cpp.

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◆ Attempt()

void AddrMan::Attempt	(	const CService &	addr,
		bool	fCountFailure,
		int64_t	nTime = `GetAdjustedTime()`
	)

Mark an entry as connection attempted to.

Definition at line 1197 of file addrman.cpp.

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◆ Connected()

void AddrMan::Connected	(	const CService &	addr,
		int64_t	nTime = `GetAdjustedTime()`
	)

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]	nTime	The time that we were last connected to this peer

Definition at line 1222 of file addrman.cpp.

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◆ FindAddressEntry()

std::optional< AddressPosition > AddrMan::FindAddressEntry ( const CAddress & addr )

Test-only function Find the address record in AddrMan and return information about its position.

Parameters

[in] addr The address record to look up.

Returns: Information about the address record in AddrMan or nullopt if address is not found.

Definition at line 1237 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 1217 of file addrman.cpp.

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◆ GetAsmap()

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

Definition at line 1232 of file addrman.cpp.

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◆ Good()

bool AddrMan::Good	(	const CService &	addr,
		int64_t	nTime = `GetAdjustedTime()`
	)

Mark an address record as accessible and attempt to move it to addrman's tried table.

Parameters

[in]	addr	Address record to attempt to move to tried table.
[in]	nTime	The time that we were last connected to this peer.

Returns: true if the address is successfully moved from the new table to the tried table.

Definition at line 1192 of file addrman.cpp.

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◆ 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 1202 of file addrman.cpp.

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◆ Select()

std::pair< CAddress, int64_t > 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. int64_t The last time we attempted to connect to that peer.

Definition at line 1212 of file addrman.cpp.

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◆ SelectTriedCollision()

std::pair< CAddress, int64_t > 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. int64_t The last time we attempted to connect to that peer.

Definition at line 1207 of file addrman.cpp.

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◆ Serialize()

template<typename Stream >

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

Definition at line 1162 of file addrman.cpp.

◆ SetServices()

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

Update an entry's service bits.

Definition at line 1227 of file addrman.cpp.

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◆ size()

size_t AddrMan::size ( ) const

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

Definition at line 1182 of file addrman.cpp.

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◆ Unserialize()

template<typename Stream >

template void AddrMan::Unserialize ( Stream & s_ )

Definition at line 1168 of file addrman.cpp.

Member Data Documentation

◆ m_impl

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

protected

Definition at line 82 of file addrman.h.

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

src/addrman.h
src/addrman.cpp

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ AddrMan()

◆ ~AddrMan()

Member Function Documentation

◆ Add()

◆ Attempt()

◆ Connected()

◆ FindAddressEntry()

◆ GetAddr()

◆ GetAsmap()

◆ Good()

◆ ResolveCollisions()

◆ Select()

◆ SelectTriedCollision()

◆ Serialize()

◆ SetServices()

◆ size()

◆ Unserialize()

Member Data Documentation

◆ m_impl