lbcd/addrmgr/knownaddress.go
Jonathan Chappelow a148fa797a addrmgr: make KnownAddress methods thread-safe
This gives KnownAddress a sync.RWMutex so the exported methods may
safely access the na (*wire.NetAddress) and lastattempt fields.
The AddrManager is updated to lock the new KnownAddress mutex before
assigning to na or lastattempt.
The other KnownAddress fields are only accessed by AddrManager, using
its own Mutex for synchronization.
2021-10-26 09:55:49 -04:00

113 lines
2.9 KiB
Go

// Copyright (c) 2013-2014 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package addrmgr
import (
"sync"
"time"
"github.com/btcsuite/btcd/wire"
)
// KnownAddress tracks information about a known network address that is used
// to determine how viable an address is.
type KnownAddress struct {
mtx sync.RWMutex // na and lastattempt
na *wire.NetAddress
srcAddr *wire.NetAddress
attempts int
lastattempt time.Time
lastsuccess time.Time
tried bool
refs int // reference count of new buckets
}
// NetAddress returns the underlying wire.NetAddress associated with the
// known address.
func (ka *KnownAddress) NetAddress() *wire.NetAddress {
ka.mtx.RLock()
defer ka.mtx.RUnlock()
return ka.na
}
// LastAttempt returns the last time the known address was attempted.
func (ka *KnownAddress) LastAttempt() time.Time {
ka.mtx.RLock()
defer ka.mtx.RUnlock()
return ka.lastattempt
}
// Services returns the services supported by the peer with the known address.
func (ka *KnownAddress) Services() wire.ServiceFlag {
ka.mtx.RLock()
defer ka.mtx.RUnlock()
return ka.na.Services
}
// The unexported methods, chance and isBad, are used from within AddrManager
// where KnownAddress field access is synchronized via it's own Mutex.
// chance returns the selection probability for a known address. The priority
// depends upon how recently the address has been seen, how recently it was last
// attempted and how often attempts to connect to it have failed.
func (ka *KnownAddress) chance() float64 {
now := time.Now()
lastAttempt := now.Sub(ka.lastattempt)
if lastAttempt < 0 {
lastAttempt = 0
}
c := 1.0
// Very recent attempts are less likely to be retried.
if lastAttempt < 10*time.Minute {
c *= 0.01
}
// Failed attempts deprioritise.
for i := ka.attempts; i > 0; i-- {
c /= 1.5
}
return c
}
// isBad returns true if the address in question has not been tried in the last
// minute and meets one of the following criteria:
// 1) It claims to be from the future
// 2) It hasn't been seen in over a month
// 3) It has failed at least three times and never succeeded
// 4) It has failed ten times in the last week
// All addresses that meet these criteria are assumed to be worthless and not
// worth keeping hold of.
func (ka *KnownAddress) isBad() bool {
if ka.lastattempt.After(time.Now().Add(-1 * time.Minute)) {
return false
}
// From the future?
if ka.na.Timestamp.After(time.Now().Add(10 * time.Minute)) {
return true
}
// Over a month old?
if ka.na.Timestamp.Before(time.Now().Add(-1 * numMissingDays * time.Hour * 24)) {
return true
}
// Never succeeded?
if ka.lastsuccess.IsZero() && ka.attempts >= numRetries {
return true
}
// Hasn't succeeded in too long?
if !ka.lastsuccess.After(time.Now().Add(-1*minBadDays*time.Hour*24)) &&
ka.attempts >= maxFailures {
return true
}
return false
}