kaspad/connmgr/seed.go
Dan Aharoni 1f35378a4d [NOD-386] Extract net parsing functionality to a shared place. (#453)
* [NOD-386] Extract net parsing functionality to a shared place.

* [NOD-386] Add extract ActiveNetParams to cmdconfig

* [NOD-386] Adding comments so go-vet won't shout at me

* [NOD-386] Rename package name to config

* [NOD-386] Rename commandConfig to configFlags

* [NOD-386] Rename function to ResolveNetwork

* [NOD-386] Fix renaming errors

* [NOD-386] Refactor network config to btcd level so APIserver and btcd could use it

* [NOD-386] Refactor network config to config package

* [NOD-386] Move ActiveNetParams to network section

* [NOD-386] Explictly return nil

* [NOD-386] Reuse activeNetParams from netwrok config

* [NOD-386] Set ActiveNetworkFlags instance to be global

* [NOD-386] Remove redundant newline

* [NOD-386] Init ActiveNetParams in address manager test

* [NOD-386] Add dnsseeder network config

* [NOD-386] Use ActiveConfig() method to access configuration
2019-11-12 10:51:36 +02:00

101 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 connmgr
import (
"fmt"
mrand "math/rand"
"net"
"strconv"
"time"
"github.com/daglabs/btcd/config"
"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) {
var dnsSeeds []string
mainConfig := config.ActiveConfig()
if mainConfig != nil && mainConfig.DNSSeed != "" {
dnsSeeds = []string{mainConfig.DNSSeed}
} else {
dnsSeeds = dagParams.DNSSeeds
}
for _, dnsseed := range 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)
}
}