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Modify the rewrite plugin to write multiple EDNS0 options (#936) (#1096)

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* Add processing mode

* Add processing mode

* Update UTs

* Update README.md

* Change to use the constant Stop

* Fix README per review comments
This commit is contained in:
Thong Huynh
2017-09-20 13:06:53 -07:00
committed by John Belamaric
parent 36c7aa6437
commit ec21f83425
7 changed files with 139 additions and 28 deletions
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46
plugin/rewrite/edns0.go
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@@ -15,6 +15,7 @@ import (
// edns0LocalRule is a rewrite rule for EDNS0_LOCAL options
type edns0LocalRule struct {
mode string
action string
code uint16
data []byte
@@ -22,6 +23,7 @@ type edns0LocalRule struct {
// edns0VariableRule is a rewrite rule for EDNS0_LOCAL options with variable
type edns0VariableRule struct {
mode string
action string
code uint16
variable string
@@ -29,6 +31,7 @@ type edns0VariableRule struct {
// ends0NsidRule is a rewrite rule for EDNS0_NSID options
type edns0NsidRule struct {
mode string
action string
}
@@ -70,6 +73,11 @@ Option:
return result
}
// Mode returns the processing mode
func (rule *edns0NsidRule) Mode() string {
return rule.mode
}
// Rewrite will alter the request EDNS0 local options
func (rule *edns0LocalRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
result := RewriteIgnored
@@ -102,8 +110,13 @@ func (rule *edns0LocalRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
return result
}
// Mode returns the processing mode
func (rule *edns0LocalRule) Mode() string {
return rule.mode
}
// newEdns0Rule creates an EDNS0 rule of the appropriate type based on the args
func newEdns0Rule(args ...string) (Rule, error) {
func newEdns0Rule(mode string, args ...string) (Rule, error) {
if len(args) < 2 {
return nil, fmt.Errorf("too few arguments for an EDNS0 rule")
}
@@ -125,25 +138,25 @@ func newEdns0Rule(args ...string) (Rule, error) {
}
//Check for variable option
if strings.HasPrefix(args[3], "{") && strings.HasSuffix(args[3], "}") {
return newEdns0VariableRule(action, args[2], args[3])
return newEdns0VariableRule(mode, action, args[2], args[3])
}
return newEdns0LocalRule(action, args[2], args[3])
return newEdns0LocalRule(mode, action, args[2], args[3])
case "nsid":
if len(args) != 2 {
return nil, fmt.Errorf("EDNS0 NSID rules do not accept args")
}
return &edns0NsidRule{action: action}, nil
return &edns0NsidRule{mode: mode, action: action}, nil
case "subnet":
if len(args) != 4 {
return nil, fmt.Errorf("EDNS0 subnet rules require exactly three args")
}
return newEdns0SubnetRule(action, args[2], args[3])
return newEdns0SubnetRule(mode, action, args[2], args[3])
default:
return nil, fmt.Errorf("invalid rule type %q", ruleType)
}
}
func newEdns0LocalRule(action, code, data string) (*edns0LocalRule, error) {
func newEdns0LocalRule(mode, action, code, data string) (*edns0LocalRule, error) {
c, err := strconv.ParseUint(code, 0, 16)
if err != nil {
return nil, err
@@ -156,11 +169,11 @@ func newEdns0LocalRule(action, code, data string) (*edns0LocalRule, error) {
return nil, err
}
}
return &edns0LocalRule{action: action, code: uint16(c), data: decoded}, nil
return &edns0LocalRule{mode: mode, action: action, code: uint16(c), data: decoded}, nil
}
// newEdns0VariableRule creates an EDNS0 rule that handles variable substitution
func newEdns0VariableRule(action, code, variable string) (*edns0VariableRule, error) {
func newEdns0VariableRule(mode, action, code, variable string) (*edns0VariableRule, error) {
c, err := strconv.ParseUint(code, 0, 16)
if err != nil {
return nil, err
@@ -169,7 +182,7 @@ func newEdns0VariableRule(action, code, variable string) (*edns0VariableRule, er
if !isValidVariable(variable) {
return nil, fmt.Errorf("unsupported variable name %q", variable)
}
return &edns0VariableRule{action: action, code: uint16(c), variable: variable}, nil
return &edns0VariableRule{mode: mode, action: action, code: uint16(c), variable: variable}, nil
}
// ipToWire writes IP address to wire/binary format, 4 or 16 bytes depends on IPV4 or IPV6.
@@ -294,6 +307,11 @@ func (rule *edns0VariableRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result
return result
}
// Mode returns the processing mode
func (rule *edns0VariableRule) Mode() string {
return rule.mode
}
func isValidVariable(variable string) bool {
switch variable {
case
@@ -311,12 +329,13 @@ func isValidVariable(variable string) bool {
// ends0SubnetRule is a rewrite rule for EDNS0 subnet options
type edns0SubnetRule struct {
mode string
v4BitMaskLen uint8
v6BitMaskLen uint8
action string
}
func newEdns0SubnetRule(action, v4BitMaskLen, v6BitMaskLen string) (*edns0SubnetRule, error) {
func newEdns0SubnetRule(mode, action, v4BitMaskLen, v6BitMaskLen string) (*edns0SubnetRule, error) {
v4Len, err := strconv.ParseUint(v4BitMaskLen, 0, 16)
if err != nil {
return nil, err
@@ -335,7 +354,7 @@ func newEdns0SubnetRule(action, v4BitMaskLen, v6BitMaskLen string) (*edns0Subnet
return nil, fmt.Errorf("invalid IPv6 bit mask length %d", v6Len)
}
return &edns0SubnetRule{action: action,
return &edns0SubnetRule{mode: mode, action: action,
v4BitMaskLen: uint8(v4Len), v6BitMaskLen: uint8(v6Len)}, nil
}
@@ -400,6 +419,11 @@ func (rule *edns0SubnetRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
return result
}
// Mode returns the processing mode
func (rule *edns0SubnetRule) Mode() string {
return rule.mode
}
// These are all defined actions.
const (
Replace = "replace"