121 lines
3.4 KiB
Go
121 lines
3.4 KiB
Go
package dnsseed
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import (
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"fmt"
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"net"
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"time"
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"github.com/caddyserver/caddy"
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/plugin"
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clog "github.com/coredns/coredns/plugin/pkg/log"
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"github.com/zcashfoundation/dnsseeder/zcash"
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"github.com/zcashfoundation/dnsseeder/zcash/network"
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)
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var (
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log = clog.NewWithPlugin("dnsseed")
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updateInterval = 15 * time.Minute
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)
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func init() { plugin.Register("dnsseed", setup) }
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// setup is the function that gets called when the config parser see the token "dnsseed". Setup is responsible
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// for parsing any extra options the example plugin may have. The first token this function sees is "dnsseed".
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func setup(c *caddy.Controller) error {
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var rootArg, networkArg, hostArg string
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c.Next() // Ignore "dnsseed" and give us the next token.
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if !c.Args(&rootArg, &networkArg, &hostArg) {
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return plugin.Error("dnsseed", c.ArgErr())
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}
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var magic network.Network
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switch networkArg {
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case "mainnet":
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magic = network.Mainnet
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case "testnet":
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magic = network.Testnet
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default:
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return plugin.Error("dnsseed", c.Errf("Config error: expected {mainnet, testnet}, got %s", networkArg))
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}
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// Automatically configure the responsive zone by network
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zone := fmt.Sprintf("%s.seeder.%s.", networkArg, rootArg)
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address, port, err := net.SplitHostPort(hostArg)
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if err != nil {
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return plugin.Error("dnsseed", c.Errf("Config error: expected 'host:port', got %s", hostArg))
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}
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// XXX: If we wanted to register Prometheus metrics, this would be the place.
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seeder, err := zcash.NewSeeder(magic)
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if err != nil {
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return plugin.Error("dnsseed", err)
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}
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// TODO load from storage if we already know some peers
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// Send the initial request for more addresses; spawns goroutines to process the responses.
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// Ready() will flip to true once we've received and confirmed at least 10 peers.
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log.Infof("Getting addresses from bootstrap peer %s:%s", address, port)
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// Connect to the bootstrap peer
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err = seeder.Connect(address, port)
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if err != nil {
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return plugin.Error("dnsseed", err)
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}
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seeder.RequestAddresses()
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seeder.DisconnectAllPeers()
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// Start the update timer
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go func() {
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log.Infof("Starting update timer. Will crawl every %.0f minutes.", updateInterval.Minutes())
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for {
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select {
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case <-time.After(updateInterval):
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runCrawl(seeder)
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}
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}
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}()
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// Add the Plugin to CoreDNS, so Servers can use it in their plugin chain.
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dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
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return ZcashSeeder{
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Next: next,
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Zones: []string{zone},
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seeder: seeder,
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}
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})
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// All OK, return a nil error.
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return nil
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}
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func runCrawl(seeder *zcash.Seeder) {
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log.Info("Beginning crawl")
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start := time.Now()
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// Slow motion crawl: we'll get them all eventually!
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// 1. Make sure our addresses are still live and leave the
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// connections open (true would disconnect immediately).
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seeder.RefreshAddresses(false)
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// 2. Request addresses from everyone we're connected to,
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// synchronously. This will block a while in an attempt
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// to catch all of the addr responses it can.
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newPeerCount := seeder.RequestAddresses()
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// 3. Disconnect from everyone & leave them alone for a while
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seeder.DisconnectAllPeers()
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elapsed := time.Now().Sub(start).Truncate(time.Second).Seconds()
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log.Infof("Crawl complete, met %d new peers of %d in %.2f seconds", newPeerCount, seeder.GetPeerCount(), elapsed)
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}
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