kaspad/connmgr/seed.go
Evgeny Khirin 7c30bc4301 [NOD-64] Remove subnetwork id supports all (#237)
* [NOD-64] Intermediate commit: need check tests on master

* [NOD-64] Commit before changing subnetwork IDS to new values

* [NOD-64] Fixed tests after changing subnetworks IDs constants

* [NOD-64] Extract duplicate code into functions

* [NOD-64] Renamed IsAllSubnetworks ==> IncludeAllSubnetworks
2019-04-03 17:03:48 +03:00

92 lines
2.6 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/daglabs/btcd/util/subnetworkid"
"github.com/daglabs/btcd/dagconfig"
"github.com/daglabs/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
// SubnetworkIDPrefixChar is the prefix of subnetworkID, when building a DNS seed request
SubnetworkIDPrefixChar byte = 'n'
// ServiceFlagPrefixChar is the prefix of service flag, when building a DNS seed request
ServiceFlagPrefixChar byte = 'x'
)
// 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(dagParams *dagconfig.Params, reqServices wire.ServiceFlag, includeAllSubnetworks bool,
subnetworkID *subnetworkid.SubnetworkID, lookupFn LookupFunc, seedFn OnSeed) {
for _, dnsseed := range dagParams.DNSSeeds {
var host string
if reqServices == wire.SFNodeNetwork {
host = dnsseed
} else {
host = fmt.Sprintf("%c%x.%s", ServiceFlagPrefixChar, uint64(reqServices), dnsseed)
}
if !includeAllSubnetworks {
if subnetworkID != nil {
host = fmt.Sprintf("%c%s.%s", SubnetworkIDPrefixChar, subnetworkID, host)
} else {
host = fmt.Sprintf("%c.%s", SubnetworkIDPrefixChar, 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: %s", 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(dagParams.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)
}
}