c5751b75a9
Replace assignments to individual fields of wire.NetAddress with creating the entire object at once, as one would do if the type was immutable. In some places this replaces the creation of a NetAddress with a high-precision timestamp with a call to a 'constructor' that converts the timestamp to single second precision. For consistency, the tests have also been changed to use single-precision timestamps. Lastly, the number of allocations in readNetAddress have been reduced by reading the services directly into the NetAddress instead of first into a temporary variable.
76 lines
2 KiB
Go
76 lines
2 KiB
Go
// Copyright (c) 2016 The btcsuite developers
|
|
// Use of this source code is governed by an ISC
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package connmgr
|
|
|
|
import (
|
|
"fmt"
|
|
mrand "math/rand"
|
|
"net"
|
|
"strconv"
|
|
"time"
|
|
|
|
"github.com/btcsuite/btcd/chaincfg"
|
|
"github.com/btcsuite/btcd/wire"
|
|
)
|
|
|
|
const (
|
|
// These constants are used by the DNS seed code to pick a random last
|
|
// seen time.
|
|
secondsIn3Days int32 = 24 * 60 * 60 * 3
|
|
secondsIn4Days int32 = 24 * 60 * 60 * 4
|
|
)
|
|
|
|
// OnSeed is the signature of the callback function which is invoked when DNS
|
|
// seeding is succesfull.
|
|
type OnSeed func(addrs []*wire.NetAddress)
|
|
|
|
// LookupFunc is the signature of the DNS lookup function.
|
|
type LookupFunc func(string) ([]net.IP, error)
|
|
|
|
// SeedFromDNS uses DNS seeding to populate the address manager with peers.
|
|
func SeedFromDNS(chainParams *chaincfg.Params, reqServices wire.ServiceFlag,
|
|
lookupFn LookupFunc, seedFn OnSeed) {
|
|
|
|
for _, dnsseed := range chainParams.DNSSeeds {
|
|
var host string
|
|
if !dnsseed.HasFiltering || reqServices == wire.SFNodeNetwork {
|
|
host = dnsseed.Host
|
|
} else {
|
|
host = fmt.Sprintf("x%x.%s", uint64(reqServices), dnsseed.Host)
|
|
}
|
|
|
|
go func(host string) {
|
|
randSource := mrand.New(mrand.NewSource(time.Now().UnixNano()))
|
|
|
|
seedpeers, err := lookupFn(host)
|
|
if err != nil {
|
|
log.Infof("DNS discovery failed on seed %s: %v", host, err)
|
|
return
|
|
}
|
|
numPeers := len(seedpeers)
|
|
|
|
log.Infof("%d addresses found from DNS seed %s", numPeers, host)
|
|
|
|
if numPeers == 0 {
|
|
return
|
|
}
|
|
addresses := make([]*wire.NetAddress, len(seedpeers))
|
|
// if this errors then we have *real* problems
|
|
intPort, _ := strconv.Atoi(chainParams.DefaultPort)
|
|
for i, peer := range seedpeers {
|
|
addresses[i] = wire.NewNetAddressTimestamp(
|
|
// bitcoind seeds with addresses from
|
|
// a time randomly selected between 3
|
|
// and 7 days ago.
|
|
time.Now().Add(-1*time.Second*time.Duration(secondsIn3Days+
|
|
randSource.Int31n(secondsIn4Days))),
|
|
0, peer, uint16(intPort))
|
|
}
|
|
|
|
seedFn(addresses)
|
|
}(host)
|
|
}
|
|
}
|