73 lines
1.9 KiB
Go
73 lines
1.9 KiB
Go
package dnsseed
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import (
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"context"
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"net"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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"github.com/zcashfoundation/dnsseeder/zcash"
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)
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// ZcashSeeder discovers IP addresses by asking Zcash peers for them.
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type ZcashSeeder struct {
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Next plugin.Handler
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Zones []string
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seeder *zcash.Seeder
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opts *options
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}
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// Name satisfies the Handler interface.
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func (zs ZcashSeeder) Name() string { return "dnsseed" }
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// Ready implements the ready.Readiness interface, once this flips to true CoreDNS
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// assumes this plugin is ready for queries; it is not checked again.
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func (zs ZcashSeeder) Ready() bool {
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// setup() has attempted an initial connection to the backing peer already.
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return zs.seeder.Ready()
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}
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func (zs ZcashSeeder) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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// Check if it's a question for us
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state := request.Request{W: w, Req: r}
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zone := plugin.Zones(zs.Zones).Matches(state.Name())
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if zone == "" {
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return plugin.NextOrFailure(zs.Name(), zs.Next, ctx, w, r)
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}
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var peerIPs []net.IP
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switch state.QType() {
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case dns.TypeA:
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peerIPs = zs.seeder.Addresses(25)
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case dns.TypeAAAA:
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peerIPs = zs.seeder.AddressesV6(25)
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default:
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return dns.RcodeNotImplemented, nil
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}
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a := new(dns.Msg)
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a.SetReply(r)
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a.Authoritative = true
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a.Answer = make([]dns.RR, 0, 25)
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for i := 0; i < len(peerIPs); i++ {
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var rr dns.RR
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if peerIPs[i].To4() == nil {
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rr = new(dns.AAAA)
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rr.(*dns.AAAA).Hdr = dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeAAAA, Ttl: zs.opts.recordTTL, Class: state.QClass()}
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rr.(*dns.AAAA).AAAA = peerIPs[i]
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} else {
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rr = new(dns.A)
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rr.(*dns.A).Hdr = dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeA, Ttl: zs.opts.recordTTL, Class: state.QClass()}
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rr.(*dns.A).A = peerIPs[i]
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}
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a.Answer = append(a.Answer, rr)
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}
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w.WriteMsg(a)
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return dns.RcodeSuccess, nil
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}
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