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plugin/rewrite - extend edns0 local variable support with metadata (#1928)

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* - add support of metadata values for edns0 local variables

* - comments from review.

* - simplify label check. Add UT

* - enhance check for Labels, add UT
- remove IsMetadataSet

* - edns0 variable - if variable is not found just ignore the rewrite.
This commit is contained in:
Francois Tur
2018-07-08 03:18:01 -04:00
committed by Miek Gieben
parent 6ec1978340
commit 7745462430
9 changed files with 132 additions and 22 deletions
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23
plugin/rewrite/edns0.go
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@@ -2,12 +2,14 @@
package rewrite
import (
"context"
"encoding/hex"
"fmt"
"net"
"strconv"
"strings"
"github.com/coredns/coredns/plugin/metadata"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
@@ -46,7 +48,7 @@ func setupEdns0Opt(r *dns.Msg) *dns.OPT {
}
// Rewrite will alter the request EDNS0 NSID option
func (rule *edns0NsidRule) Rewrite(state request.Request) Result {
func (rule *edns0NsidRule) Rewrite(ctx context.Context, state request.Request) Result {
o := setupEdns0Opt(state.Req)
for _, s := range o.Option {
@@ -74,7 +76,7 @@ func (rule *edns0NsidRule) Mode() string { return rule.mode }
func (rule *edns0NsidRule) GetResponseRule() ResponseRule { return ResponseRule{} }
// Rewrite will alter the request EDNS0 local options.
func (rule *edns0LocalRule) Rewrite(state request.Request) Result {
func (rule *edns0LocalRule) Rewrite(ctx context.Context, state request.Request) Result {
o := setupEdns0Opt(state.Req)
for _, s := range o.Option {
@@ -174,7 +176,7 @@ func newEdns0VariableRule(mode, action, code, variable string) (*edns0VariableRu
}
// ruleData returns the data specified by the variable.
func (rule *edns0VariableRule) ruleData(state request.Request) ([]byte, error) {
func (rule *edns0VariableRule) ruleData(ctx context.Context, state request.Request) ([]byte, error) {
switch rule.variable {
case queryName:
@@ -199,12 +201,17 @@ func (rule *edns0VariableRule) ruleData(state request.Request) ([]byte, error) {
return []byte(state.Proto()), nil
}
fetcher := metadata.ValueFunc(ctx, rule.variable[1:len(rule.variable)-1])
if fetcher != nil {
return []byte(fetcher()), nil
}
return nil, fmt.Errorf("unable to extract data for variable %s", rule.variable)
}
// Rewrite will alter the request EDNS0 local options with specified variables.
func (rule *edns0VariableRule) Rewrite(state request.Request) Result {
data, err := rule.ruleData(state)
func (rule *edns0VariableRule) Rewrite(ctx context.Context, state request.Request) Result {
data, err := rule.ruleData(ctx, state)
if err != nil || data == nil {
return RewriteIgnored
}
@@ -249,6 +256,10 @@ func isValidVariable(variable string) bool {
serverPort:
return true
}
// we cannot validate the labels of metadata - but we can verify it has the syntax of a label
if strings.HasPrefix(variable, "{") && strings.HasSuffix(variable, "}") && metadata.IsLabel(variable[1:len(variable)-1]) {
return true
}
return false
}
@@ -310,7 +321,7 @@ func (rule *edns0SubnetRule) fillEcsData(state request.Request, ecs *dns.EDNS0_S
}
// Rewrite will alter the request EDNS0 subnet option.
func (rule *edns0SubnetRule) Rewrite(state request.Request) Result {
func (rule *edns0SubnetRule) Rewrite(ctx context.Context, state request.Request) Result {
o := setupEdns0Opt(state.Req)
for _, s := range o.Option {