kaspad/connmgr/seed.go
Ori Newman 5a99e4d2f3
[NOD-806] Exit early after panic (#650)
* [NOD-806] After panic, gracefully stop logs, and then exit immediately

* [NOD-806] Convert non-kaspad applications to use the new spawn

* [NOD-806] Fix disabled log at rpcclient

* [NOD-806] Refactor HandlePanic

* [NOD-806] Cancel Logger interface

* [NOD-806] Remove redundant spawn checks from waitgroup_test.go

* [NOD-806] Use caller subsystem when logging panics

* [NOD-806] Fix go vet errors
2020-03-08 11:24:37 +02:00

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 connmgr
import (
"fmt"
mrand "math/rand"
"net"
"strconv"
"time"
"github.com/kaspanet/kaspad/config"
"github.com/kaspanet/kaspad/util/subnetworkid"
"github.com/kaspanet/kaspad/dagconfig"
"github.com/kaspanet/kaspad/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)
}
}
spawn(func() {
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(
// seed 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)
})
}
}