ipld-eth-server/vendor/github.com/btcsuite/btcd/addrmgr/knownaddress.go

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// 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 (
"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 {
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 {
return ka.na
}
// LastAttempt returns the last time the known address was attempted.
func (ka *KnownAddress) LastAttempt() time.Time {
return ka.lastattempt
}
// 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
}