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Add ip mutation to dns server #93

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Add ip mutation to dns server #93

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2 changes: 1 addition & 1 deletion go.mod
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ require (
github.com/edwarnicke/grpcfd v1.1.2
github.com/kelseyhightower/envconfig v1.4.0
github.com/miekg/dns v1.1.50
github.com/networkservicemesh/api v1.6.2-0.20221205183940-84c7ff837cdd
github.com/networkservicemesh/api v1.7.2-0.20230123083145-4a6c3ec589e1
github.com/networkservicemesh/sdk v0.5.1-0.20230109230417-1492e69a650d
github.com/networkservicemesh/sdk-kernel v0.0.0-20230109230713-03b9b6155f6d
github.com/pkg/errors v0.9.1
Expand Down
4 changes: 2 additions & 2 deletions go.sum
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Original file line number Diff line number Diff line change
Expand Up @@ -192,8 +192,8 @@ github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369 h1:I0XW9+e1XWDxdcEniV4rQAIOPUGDq67JSCiRCgGCZLI=
github.com/miekg/dns v1.1.50 h1:DQUfb9uc6smULcREF09Uc+/Gd46YWqJd5DbpPE9xkcA=
github.com/miekg/dns v1.1.50/go.mod h1:e3IlAVfNqAllflbibAZEWOXOQ+Ynzk/dDozDxY7XnME=
github.com/networkservicemesh/api v1.6.2-0.20221205183940-84c7ff837cdd h1:26HR90HrJFZHIPPP3SCLGNRpPCMFoEnSSZfhHH8MPSo=
github.com/networkservicemesh/api v1.6.2-0.20221205183940-84c7ff837cdd/go.mod h1:hOF2844BSstH1311oDMDgqqXS+kdc77htZNPRKl9mf8=
github.com/networkservicemesh/api v1.7.2-0.20230123083145-4a6c3ec589e1 h1:RxNKksXsXsnDsEo+Cfn43pdPfML024ad//QcdKfgXK4=
github.com/networkservicemesh/api v1.7.2-0.20230123083145-4a6c3ec589e1/go.mod h1:hOF2844BSstH1311oDMDgqqXS+kdc77htZNPRKl9mf8=
github.com/networkservicemesh/sdk v0.5.1-0.20230109230417-1492e69a650d h1:1EhczRkzfkutymvDj5XYinD68omLpFk2F2kJdhzYG+U=
github.com/networkservicemesh/sdk v0.5.1-0.20230109230417-1492e69a650d/go.mod h1:++MSpR2wuFlCpCYoR6lELxJ4ILKd650vDQ8d9CtGAzA=
github.com/networkservicemesh/sdk-kernel v0.0.0-20230109230713-03b9b6155f6d h1:DKXaQ1Yq7Ep6Cgo54Ip1QxgLwnqaND0MJdb4I+THhKI=
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21 changes: 19 additions & 2 deletions internal/pkg/dns/dns.go
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Expand Up @@ -35,6 +35,7 @@ const dnsQuestionNameFilter = "cluster.local."

// ProxyRewriteServer - DNS server with rewrite function
type ProxyRewriteServer struct {
RewriteIP bool
RewriteTO net.IP
ListenOn string
ResolveConfPath string
Expand Down Expand Up @@ -95,7 +96,7 @@ func (p *ProxyRewriteServer) ServeDNS(rw dns.ResponseWriter, m *dns.Msg) {
dns.HandleFailed(rw, m)
return
}
var networks = []string{"tcp", "udp"}
var networks = []string{"udp"}

for _, network := range networks {
var client = dns.Client{
Expand All @@ -107,9 +108,16 @@ func (p *ProxyRewriteServer) ServeDNS(rw dns.ResponseWriter, m *dns.Msg) {
fmt.Println(err.Error())
continue
}
if p.RewriteIP {
for _, answer := range msg.Answer {
p.rewriteIP(answer)
}
}

for _, answer := range msg.Answer {
p.rewriteIP(answer)
p.changeFirstByte(answer)
}

if err := rw.WriteMsg(msg); err == nil {
return
}
Expand All @@ -131,3 +139,12 @@ func (p *ProxyRewriteServer) rewriteIP(rr dns.RR) {
}
}
}

func (p *ProxyRewriteServer) changeFirstByte(rr dns.RR) {
switch rr.Header().Rrtype {
case dns.TypeA:
if p.RewriteTO.To4() != nil {
rr.(*dns.A).A[0] = 199
}
}
}
2 changes: 2 additions & 0 deletions main.go
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Expand Up @@ -89,6 +89,7 @@ type Config struct {
LogLevel string `default:"INFO" desc:"Log level" split_words:"true"`
OpenTelemetryEndpoint string `default:"otel-collector.observability.svc.cluster.local:4317" desc:"OpenTelemetry Collector Endpoint"`
RulesConfigPath string `default:"" desc:"Path to a configmap with iptables rules" split_words:"true"`
RewriteIP bool `default:"false" desc:"Rewrite ip with nse-l7-proxy ip in DNS response" split_worlds:"true"`
}

// Process prints and processes env to config
Expand Down Expand Up @@ -298,6 +299,7 @@ func main() {
log.FromContext(ctx).Infof("executing phase 7: run DNS server")
// ********************************************************************************
dnsServer := &dns.ProxyRewriteServer{
RewriteIP: config.RewriteIP,
RewriteTO: ip,
ListenOn: ":53",
}
Expand Down