addrmgr

package
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 Go to latest Published: Apr 26, 2017 License: ISC Imports: 19 Imported by: 0

Documentation

Overview

Package addrmgr implements concurrency safe Decred address manager.

Address Manager Overview

In order maintain the peer-to-peer Decred network, there needs to be a source of addresses to connect to as nodes come and go. The Decred protocol provides a the getaddr and addr messages to allow peers to communicate known addresses with each other. However, there needs to a mechanism to store those results and select peers from them. It is also important to note that remote peers can't be trusted to send valid peers nor attempt to provide you with only peers they control with malicious intent.

With that in mind, this package provides a concurrency safe address manager for caching and selecting peers in a non-determinstic manner. The general idea is the caller adds addresses to the address manager and notifies it when addresses are connected, known good, and attempted. The caller also requests addresses as it needs them.

The address manager internally segregates the addresses into groups and non-deterministically selects groups in a cryptographically random manner. This reduce the chances multiple addresses from the same nets are selected which generally helps provide greater peer diversity, and perhaps more importantly, drastically reduces the chances an attacker is able to coerce your peer into only connecting to nodes they control.

The address manager also understands routability and tor addresses and tries hard to only return routable addresses. In addition, it uses the information provided by the caller about connected, known good, and attempted addresses to periodically purge peers which no longer appear to be good peers as well as bias the selection toward known good peers. The general idea is to make a best effort at only providing usuable addresses.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func DisableLog 

func DisableLog()

DisableLog disables all library log output. Logging output is disabled by default until either UseLogger or SetLogWriter are called.

func GroupKey 

func GroupKey(na *wire.NetAddress) string

GroupKey returns a string representing the network group an address is part of. This is the /16 for IPv4, the /32 (/36 for he.net) for IPv6, the string "local" for a local address, the string "tor:key" where key is the /4 of the onion address for tor address, and the string "unroutable" for an unroutable address.

func IsIPv4 

func IsIPv4(na *wire.NetAddress) bool

IsIPv4 returns whether or not the given address is an IPv4 address.

func IsLocal 

func IsLocal(na *wire.NetAddress) bool

IsLocal returns whether or not the given address is a local address.

func IsOnionCatTor 

func IsOnionCatTor(na *wire.NetAddress) bool

IsOnionCatTor returns whether or not the passed address is in the IPv6 range used by bitcoin to support Tor (fd87:d87e:eb43::/48). Note that this range is the same range used by OnionCat, which is part of the RFC4193 unique local IPv6 range.

func IsRFC1918 

func IsRFC1918(na *wire.NetAddress) bool

IsRFC1918 returns whether or not the passed address is part of the IPv4 private network address space as defined by RFC1918 (10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16).

func IsRFC2544 

func IsRFC2544(na *wire.NetAddress) bool

IsRFC2544 returns whether or not the passed address is part of the IPv4 address space as defined by RFC2544 (198.18.0.0/15)

func IsRFC3849 

func IsRFC3849(na *wire.NetAddress) bool

IsRFC3849 returns whether or not the passed address is part of the IPv6 documentation range as defined by RFC3849 (2001:DB8::/32).

func IsRFC3927 

func IsRFC3927(na *wire.NetAddress) bool

IsRFC3927 returns whether or not the passed address is part of the IPv4 autoconfiguration range as defined by RFC3927 (169.254.0.0/16).

func IsRFC3964 

func IsRFC3964(na *wire.NetAddress) bool

IsRFC3964 returns whether or not the passed address is part of the IPv6 to IPv4 encapsulation range as defined by RFC3964 (2002::/16).

func IsRFC4193 

func IsRFC4193(na *wire.NetAddress) bool

IsRFC4193 returns whether or not the passed address is part of the IPv6 unique local range as defined by RFC4193 (FC00::/7).

func IsRFC4380 

func IsRFC4380(na *wire.NetAddress) bool

IsRFC4380 returns whether or not the passed address is part of the IPv6 teredo tunneling over UDP range as defined by RFC4380 (2001::/32).

func IsRFC4843 

func IsRFC4843(na *wire.NetAddress) bool

IsRFC4843 returns whether or not the passed address is part of the IPv6 ORCHID range as defined by RFC4843 (2001:10::/28).

func IsRFC4862 

func IsRFC4862(na *wire.NetAddress) bool

IsRFC4862 returns whether or not the passed address is part of the IPv6 stateless address autoconfiguration range as defined by RFC4862 (FE80::/64).

func IsRFC5737 

func IsRFC5737(na *wire.NetAddress) bool

IsRFC5737 returns whether or not the passed address is part of the IPv4 documentation address space as defined by RFC5737 (192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24)

func IsRFC6052 

func IsRFC6052(na *wire.NetAddress) bool

IsRFC6052 returns whether or not the passed address is part of the IPv6 well-known prefix range as defined by RFC6052 (64:FF9B::/96).

func IsRFC6145 

func IsRFC6145(na *wire.NetAddress) bool

IsRFC6145 returns whether or not the passed address is part of the IPv6 to IPv4 translated address range as defined by RFC6145 (::FFFF:0:0:0/96).

func IsRFC6598 

func IsRFC6598(na *wire.NetAddress) bool

IsRFC6598 returns whether or not the passed address is part of the IPv4 shared address space specified by RFC6598 (100.64.0.0/10)

func IsRoutable 

func IsRoutable(na *wire.NetAddress) bool

IsRoutable returns whether or not the passed address is routable over the public internet. This is true as long as the address is valid and is not in any reserved ranges.

func IsValid 

func IsValid(na *wire.NetAddress) bool

IsValid returns whether or not the passed address is valid. The address is considered invalid under the following circumstances: IPv4: It is either a zero or all bits set address. IPv6: It is either a zero or RFC3849 documentation address.

func NetAddressKey 

func NetAddressKey(na *wire.NetAddress) string

NetAddressKey returns a string key in the form of ip:port for IPv4 addresses or [ip]:port for IPv6 addresses.

func UseLogger 

func UseLogger(logger btclog.Logger)

UseLogger uses a specified Logger to output package logging info. This should be used in preference to SetLogWriter if the caller is also using btclog.

Types

type AddrManager 

type AddrManager struct {
	// contains filtered or unexported fields
}

AddrManager provides a concurrency safe address manager for caching potential peers on the decred network.

func New 

func New(dataDir string, lookupFunc func(string) ([]net.IP, error)) *AddrManager

New returns a new decred address manager. Use Start to begin processing asynchronous address updates.

func (*AddrManager) AddAddress 

func (a *AddrManager) AddAddress(addr, srcAddr *wire.NetAddress)

AddAddress adds a new address to the address manager. It enforces a max number of addresses and silently ignores duplicate addresses. It is safe for concurrent access.

func (*AddrManager) AddAddressByIP 

func (a *AddrManager) AddAddressByIP(addrIP string) error

AddAddressByIP adds an address where we are given an ip:port and not a wire.NetAddress.

func (*AddrManager) AddAddresses 

func (a *AddrManager) AddAddresses(addrs []*wire.NetAddress, srcAddr *wire.NetAddress)

AddAddresses adds new addresses to the address manager. It enforces a max number of addresses and silently ignores duplicate addresses. It is safe for concurrent access.

func (*AddrManager) AddLocalAddress 

func (a *AddrManager) AddLocalAddress(na *wire.NetAddress, priority AddressPriority) error

AddLocalAddress adds na to the list of known local addresses to advertise with the given priority.

func (*AddrManager) AddressCache 

func (a *AddrManager) AddressCache() []*wire.NetAddress

AddressCache returns the current address cache. It must be treated as read-only (but since it is a copy now, this is not as dangerous).

func (*AddrManager) Attempt 

func (a *AddrManager) Attempt(addr *wire.NetAddress)

Attempt increases the given address' attempt counter and updates the last attempt time.

func (*AddrManager) Connected 

func (a *AddrManager) Connected(addr *wire.NetAddress)

Connected Marks the given address as currently connected and working at the current time. The address must already be known to AddrManager else it will be ignored.

func (*AddrManager) DeserializeNetAddress 

func (a *AddrManager) DeserializeNetAddress(addr string) (*wire.NetAddress, error)

DeserializeNetAddress converts a given address string to a *wire.NetAddress

func (*AddrManager) GetAddress 

func (a *AddrManager) GetAddress() *KnownAddress

GetAddress returns a single address that should be routable. It picks a random one from the possible addresses with preference given to ones that have not been used recently and should not pick 'close' addresses consecutively.

func (*AddrManager) GetBestLocalAddress 

func (a *AddrManager) GetBestLocalAddress(remoteAddr *wire.NetAddress) *wire.NetAddress

GetBestLocalAddress returns the most appropriate local address to use for the given remote address.

func (*AddrManager) Good 

func (a *AddrManager) Good(addr *wire.NetAddress)

Good marks the given address as good. To be called after a successful connection and version exchange. If the address is unknown to the address manager it will be ignored.

func (*AddrManager) HostToNetAddress 

func (a *AddrManager) HostToNetAddress(host string, port uint16, services wire.ServiceFlag) (*wire.NetAddress, error)

HostToNetAddress returns a netaddress given a host address. If the address is a tor .onion address this will be taken care of. else if the host is not an IP address it will be resolved (via tor if required).

func (*AddrManager) NeedMoreAddresses 

func (a *AddrManager) NeedMoreAddresses() bool

NeedMoreAddresses returns whether or not the address manager needs more addresses.

func (*AddrManager) NumAddresses 

func (a *AddrManager) NumAddresses() int

NumAddresses returns the number of addresses known to the address manager.

func (*AddrManager) Start 

func (a *AddrManager) Start()

Start begins the core address handler which manages a pool of known addresses, timeouts, and interval based writes.

func (*AddrManager) Stop 

func (a *AddrManager) Stop() error

Stop gracefully shuts down the address manager by stopping the main handler.

type AddressPriority 

type AddressPriority int

AddressPriority type is used to describe the hierarchy of local address discovery methods. 

const (
	// InterfacePrio signifies the address is on a local interface
	InterfacePrio AddressPriority = iota

	// BoundPrio signifies the address has been explicitly bounded to.
	BoundPrio

	// UpnpPrio signifies the address was obtained from UPnP.
	UpnpPrio

	// HTTPPrio signifies the address was obtained from an external HTTP service.
	HTTPPrio

	// ManualPrio signifies the address was provided by --externalip.
	ManualPrio
)

type KnownAddress 

type KnownAddress struct {
	// contains filtered or unexported fields
}

KnownAddress tracks information about a known network address that is used to determine how viable an address is.

func (*KnownAddress) LastAttempt 

func (ka *KnownAddress) LastAttempt() time.Time

LastAttempt returns the last time the known address was attempted.

func (*KnownAddress) NetAddress 

func (ka *KnownAddress) NetAddress() *wire.NetAddress

NetAddress returns the underlying wire.NetAddress associated with the known address.

Source Files

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