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Managment server is xds management server as well

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Signed-off-by: Miek Gieben <miek@miek.nl>
This commit is contained in:
Miek Gieben
2020-03-04 15:38:29 +01:00
parent f72ecc7423
commit 2d67767764
4 changed files with 116 additions and 83 deletions
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101
plugin/traffic/traffic.go
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@@ -4,7 +4,6 @@ import (
"context"
"crypto/tls"
"fmt"
"net"
"strconv"
"strings"
"time"
@@ -21,6 +20,7 @@ import (
type Traffic struct {
c *xds.Client
node string
mgmt string
tlsConfig *tls.Config
hosts []string
@@ -29,9 +29,6 @@ type Traffic struct {
origins []string
loc []xds.Locality
grpcSRV []dns.RR // SRV records for grpc LB
grpcAddr []dns.RR // Address records for each LB (taken from **TOO**)
Next plugin.Handler
}
@@ -54,26 +51,51 @@ func (t *Traffic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg
sockaddr, ok := t.c.Select(cluster, t.loc, t.health)
if !ok {
// ok the cluster (which has potentially extra labels), doesn't exist, but we may have a query for endpoint-0.<cluster>.
// check if we have 2 labels and that the first equals endpoint-0.
if dns.CountLabel(cluster) != 2 {
m.Ns = soa(state.Zone)
m.Rcode = dns.RcodeNameError
w.WriteMsg(m)
return 0, nil
}
// ok this cluster doesn't exist, potentially due to extra labels, which may be garbage or legit queries:
// legit is:
// endpoint-N.cluster
// _grpclb._tcp.cluster
// _tcp.cluster
labels := dns.SplitDomainName(cluster)
if strings.HasPrefix(labels[0], "endpoint-") {
// recheck if the cluster exist.
cluster = labels[1]
sockaddr, ok = t.c.Select(cluster, t.loc, t.health)
if !ok {
switch len(labels) {
case 2:
// endpoint or _tcp
if strings.ToLower(labels[0]) == "_tcp" {
// nodata, because empty non-terminal
m.Ns = soa(state.Zone)
m.Rcode = dns.RcodeSuccess
w.WriteMsg(m)
return 0, nil
}
if strings.HasPrefix(strings.ToLower(labels[0]), "endpoint-") {
// recheck if the cluster exist.
cluster = labels[1]
sockaddr, ok = t.c.Select(cluster, t.loc, t.health)
if !ok {
m.Ns = soa(state.Zone)
m.Rcode = dns.RcodeNameError
w.WriteMsg(m)
return 0, nil
}
return t.serveEndpoint(ctx, state, labels[0], cluster)
}
case 3:
if strings.ToLower(labels[0]) != "_grpclb" || strings.ToLower(labels[1]) != "_tcp" {
m.Ns = soa(state.Zone)
m.Rcode = dns.RcodeNameError
w.WriteMsg(m)
return 0, nil
}
return t.serveEndpoint(ctx, state, labels[0], cluster)
// OK, _grcplb._tcp query; we need to return the endpoint for the mgmt cluster *NOT* the cluster
// we got the query for. This should exist, but we'll check later anyway
cluster = t.mgmt
sockaddr, _ = t.c.Select(cluster, t.loc, t.health)
break
default:
m.Ns = soa(state.Zone)
m.Rcode = dns.RcodeNameError
w.WriteMsg(m)
return 0, nil
}
}
@@ -193,46 +215,3 @@ func soa(z string) []dns.RR {
Minttl: 5,
}}
}
// srv record for grpclb endpoint.
func srv(i int, host, zone string) *dns.SRV {
target := fmt.Sprintf("grpclb-%d.%s", i, zone)
hdr := dns.RR_Header{Name: dnsutil.Join("_grpclb._tcp", zone), Class: dns.ClassINET, Rrtype: dns.TypeSRV}
_, p, _ := net.SplitHostPort(host) // err ignored already checked in setup
port, _ := strconv.Atoi(p)
return &dns.SRV{
Hdr: hdr,
// prio, weight -> 0
Port: uint16(port),
Target: target,
}
}
func a(i int, host, zone string) *dns.A {
owner := fmt.Sprintf("grpclb-%d.%s", i, zone)
hdr := dns.RR_Header{Name: owner, Class: dns.ClassINET, Rrtype: dns.TypeA}
h, _, _ := net.SplitHostPort(host)
ip := net.ParseIP(h)
if ip == nil {
return nil
}
if ip.To4() == nil {
return nil
}
return &dns.A{Hdr: hdr, A: ip.To4()}
}
func aaaa(i int, host, zone string) *dns.AAAA {
owner := fmt.Sprintf("grpclb-%d.%s", i, zone)
hdr := dns.RR_Header{Name: owner, Class: dns.ClassINET, Rrtype: dns.TypeAAAA}
h, _, _ := net.SplitHostPort(host)
ip := net.ParseIP(h)
if ip == nil {
return nil
}
if ip.To4() != nil {
return nil
}
return &dns.AAAA{Hdr: hdr, AAAA: ip.To16()}
}