stasatdaglabs d14809694f
[NOD-1223] Reorganize directory structure (#874)
* [NOD-1223] Delete unused files/packages.

* [NOD-1223] Move signal and limits to the os package.

* [NOD-1223] Put database and dbaccess into the db package.

* [NOD-1223] Fold the logs package into the logger package.

* [NOD-1223] Rename domainmessage to appmessage.

* [NOD-1223] Rename to/from DomainMessage to AppMessage.

* [NOD-1223] Move appmessage to the app packge.

* [NOD-1223] Move protocol to the app packge.

* [NOD-1223] Move the network package to the infrastructure packge.

* [NOD-1223] Rename cmd to executables.

* [NOD-1223] Fix go.doc in the logger package.
2020-08-18 10:26:39 +03:00

100 lines
2.8 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 dnsseed
import (
"fmt"
"github.com/kaspanet/kaspad/app/appmessage"
"math/rand"
"net"
"strconv"
"time"
"github.com/kaspanet/kaspad/util/mstime"
"github.com/kaspanet/kaspad/util/subnetworkid"
"github.com/kaspanet/kaspad/domain/dagconfig"
)
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 successful.
type OnSeed func(addrs []*appmessage.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, customSeed string, reqServices appmessage.ServiceFlag, includeAllSubnetworks bool,
subnetworkID *subnetworkid.SubnetworkID, lookupFn LookupFunc, seedFn OnSeed) {
var dnsSeeds []string
if customSeed != "" {
dnsSeeds = []string{customSeed}
} else {
dnsSeeds = dagParams.DNSSeeds
}
for _, dnsseed := range dnsSeeds {
var host string
if reqServices == appmessage.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)
}
}
spawn("SeedFromDNS", func() {
randSource := rand.New(rand.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([]*appmessage.NetAddress, len(seedPeers))
// if this errors then we have *real* problems
intPort, _ := strconv.Atoi(dagParams.DefaultPort)
for i, peer := range seedPeers {
addresses[i] = appmessage.NewNetAddressTimestamp(
// seed with addresses from a time randomly selected
// between 3 and 7 days ago.
mstime.Now().Add(-1*time.Second*time.Duration(secondsIn3Days+
randSource.Int31n(secondsIn4Days))),
0, peer, uint16(intPort))
}
seedFn(addresses)
})
}
}