82 lines
1.8 KiB
Go
82 lines
1.8 KiB
Go
package grpc
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import (
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"context"
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"crypto/tls"
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"strconv"
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"time"
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"github.com/coredns/coredns/pb"
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"github.com/miekg/dns"
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"google.golang.org/grpc"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/credentials"
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"google.golang.org/grpc/credentials/insecure"
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"google.golang.org/grpc/status"
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)
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// Proxy defines an upstream host.
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type Proxy struct {
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addr string
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// connection
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client pb.DnsServiceClient
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dialOpts []grpc.DialOption
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}
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// newProxy returns a new proxy.
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func newProxy(addr string, tlsConfig *tls.Config) (*Proxy, error) {
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p := &Proxy{
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addr: addr,
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}
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if tlsConfig != nil {
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p.dialOpts = append(p.dialOpts, grpc.WithTransportCredentials(credentials.NewTLS(tlsConfig)))
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} else {
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p.dialOpts = append(p.dialOpts, grpc.WithTransportCredentials(insecure.NewCredentials()))
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}
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conn, err := grpc.Dial(p.addr, p.dialOpts...)
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if err != nil {
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return nil, err
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}
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p.client = pb.NewDnsServiceClient(conn)
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return p, nil
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}
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// query sends the request and waits for a response.
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func (p *Proxy) query(ctx context.Context, req *dns.Msg) (*dns.Msg, error) {
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start := time.Now()
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msg, err := req.Pack()
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if err != nil {
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return nil, err
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}
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reply, err := p.client.Query(ctx, &pb.DnsPacket{Msg: msg})
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if err != nil {
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// if not found message, return empty message with NXDomain code
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if status.Code(err) == codes.NotFound {
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m := new(dns.Msg).SetRcode(req, dns.RcodeNameError)
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return m, nil
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}
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return nil, err
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}
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ret := new(dns.Msg)
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if err := ret.Unpack(reply.Msg); err != nil {
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return nil, err
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}
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rc, ok := dns.RcodeToString[ret.Rcode]
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if !ok {
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rc = strconv.Itoa(ret.Rcode)
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}
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RequestCount.WithLabelValues(p.addr).Add(1)
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RcodeCount.WithLabelValues(rc, p.addr).Add(1)
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RequestDuration.WithLabelValues(p.addr).Observe(time.Since(start).Seconds())
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return ret, nil
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}
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