plugin/rewrite: use request.Request and other cleanups (#1920)

This was done anyway, but only deep in the functions, just do this
everywhere; allows for shorter code and request.Request allows for
caching as well.

Cleanups, make it more Go like.
* remove unneeded switches
* remove testdir (why was this there??)
* simplify the logic
* remove unneeded variables
* put short functions on a single line
* fix documentation.
* spin off wire funcs in wire.go, make them functions.

Signed-off-by: Miek Gieben <miek@miek.nl>

plugin/rewrite/class.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/coredns/coredns/request"
+
 	"github.com/miekg/dns"
 )
 
@@ -27,22 +29,18 @@ func newClassRule(nextAction string, args ...string) (Rule, error) {
 }
 
 // Rewrite rewrites the the current request.
-func (rule *classRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *classRule) Rewrite(state request.Request) Result {
 	if rule.fromClass > 0 && rule.toClass > 0 {
-		if r.Question[0].Qclass == rule.fromClass {
+		if state.Req.Question[0].Qclass == rule.fromClass {
-			r.Question[0].Qclass = rule.toClass
+			state.Req.Question[0].Qclass = rule.toClass
 			return RewriteDone
 		}
 	}
 	return RewriteIgnored
 }
 
-// Mode returns the processing mode
+// Mode returns the processing mode.
-func (rule *classRule) Mode() string {
+func (rule *classRule) Mode() string { return rule.NextAction }
-	return rule.NextAction
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *classRule) GetResponseRule() ResponseRule {
+func (rule *classRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}

plugin/rewrite/condition.go

@@ -10,7 +10,7 @@ import (
 	"github.com/miekg/dns"
 )
 
-// Operators
+// Operators that are defined.
 const (
 	Is         = "is"
 	Not        = "not"
@@ -22,13 +22,7 @@ const (
 	NotMatch   = "not_match"
 )
 
-func operatorError(operator string) error {
+func newReplacer(r *dns.Msg) replacer.Replacer { return replacer.New(r, nil, "") }
-	return fmt.Errorf("invalid operator %v", operator)
-}
-
-func newReplacer(r *dns.Msg) replacer.Replacer {
-	return replacer.New(r, nil, "")
-}
 
 // condition is a rewrite condition.
 type condition func(string, string) bool
@@ -44,53 +38,35 @@ var conditions = map[string]condition{
 	NotMatch:   notMatchFunc,
 }
 
-// isFunc is condition for Is operator.
+// isFunc is condition for Is operator. It checks for equality.
-// It checks for equality.
+func isFunc(a, b string) bool { return a == b }
-func isFunc(a, b string) bool {
-	return a == b
-}
 
-// notFunc is condition for Not operator.
+// notFunc is condition for Not operator. It checks for inequality.
-// It checks for inequality.
+func notFunc(a, b string) bool { return a != b }
-func notFunc(a, b string) bool {
-	return a != b
-}
 
-// hasFunc is condition for Has operator.
+// hasFunc is condition for Has operator. It checks if b is a substring of a.
-// It checks if b is a substring of a.
+func hasFunc(a, b string) bool { return strings.Contains(a, b) }
-func hasFunc(a, b string) bool {
-	return strings.Contains(a, b)
-}
 
-// notHasFunc is condition for NotHas operator.
+// notHasFunc is condition for NotHas operator. It checks if b is not a substring of a.
-// It checks if b is not a substring of a.
+func notHasFunc(a, b string) bool { return !strings.Contains(a, b) }
-func notHasFunc(a, b string) bool {
-	return !strings.Contains(a, b)
-}
 
-// startsWithFunc is condition for StartsWith operator.
+// startsWithFunc is condition for StartsWith operator. It checks if b is a prefix of a.
-// It checks if b is a prefix of a.
+func startsWithFunc(a, b string) bool { return strings.HasPrefix(a, b) }
-func startsWithFunc(a, b string) bool {
-	return strings.HasPrefix(a, b)
-}
 
-// endsWithFunc is condition for EndsWith operator.
+// endsWithFunc is condition for EndsWith operator. It checks if b is a suffix of a.
-// It checks if b is a suffix of a.
 func endsWithFunc(a, b string) bool {
 	// TODO(miek): IsSubDomain
 	return strings.HasSuffix(a, b)
 }
 
-// matchFunc is condition for Match operator.
+// matchFunc is condition for Match operator. It does regexp matching of a against pattern in b
-// It does regexp matching of a against pattern in b
 // and returns if they match.
 func matchFunc(a, b string) bool {
 	matched, _ := regexp.MatchString(b, a)
 	return matched
 }
 
-// notMatchFunc is condition for NotMatch operator.
+// notMatchFunc is condition for NotMatch operator. It does regexp matching of a against pattern in b
-// It does regexp matching of a against pattern in b
 // and returns if they do not match.
 func notMatchFunc(a, b string) bool {
 	matched, _ := regexp.MatchString(b, a)
@@ -122,7 +98,7 @@ func (i If) True(r *dns.Msg) bool {
 // NewIf creates a new If condition.
 func NewIf(a, operator, b string) (If, error) {
 	if _, ok := conditions[operator]; !ok {
-		return If{}, operatorError(operator)
+		return If{}, fmt.Errorf("invalid operator %v", operator)
 	}
 	return If{
 		A:        a,

plugin/rewrite/edns0.go

@@ -2,7 +2,6 @@
 package rewrite
 
 import (
-	"encoding/binary"
 	"encoding/hex"
 	"fmt"
 	"net"
@@ -14,7 +13,7 @@ import (
 	"github.com/miekg/dns"
 )
 
-// edns0LocalRule is a rewrite rule for EDNS0_LOCAL options
+// edns0LocalRule is a rewrite rule for EDNS0_LOCAL options.
 type edns0LocalRule struct {
 	mode   string
 	action string
@@ -22,7 +21,7 @@ type edns0LocalRule struct {
 	data   []byte
 }
 
-// edns0VariableRule is a rewrite rule for EDNS0_LOCAL options with variable
+// edns0VariableRule is a rewrite rule for EDNS0_LOCAL options with variable.
 type edns0VariableRule struct {
 	mode     string
 	action   string
@@ -30,13 +29,13 @@ type edns0VariableRule struct {
 	variable string
 }
 
-// ends0NsidRule is a rewrite rule for EDNS0_NSID options
+// ends0NsidRule is a rewrite rule for EDNS0_NSID options.
 type edns0NsidRule struct {
 	mode   string
 	action string
 }
 
-// setupEdns0Opt will retrieve the EDNS0 OPT or create it if it does not exist
+// setupEdns0Opt will retrieve the EDNS0 OPT or create it if it does not exist.
 func setupEdns0Opt(r *dns.Msg) *dns.OPT {
 	o := r.IsEdns0()
 	if o == nil {
@@ -47,82 +46,62 @@ func setupEdns0Opt(r *dns.Msg) *dns.OPT {
 }
 
 // Rewrite will alter the request EDNS0 NSID option
-func (rule *edns0NsidRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *edns0NsidRule) Rewrite(state request.Request) Result {
-	result := RewriteIgnored
+	o := setupEdns0Opt(state.Req)
-	o := setupEdns0Opt(r)
+
-	found := false
-Option:
 	for _, s := range o.Option {
-		switch e := s.(type) {
+		if e, ok := s.(*dns.EDNS0_NSID); ok {
-		case *dns.EDNS0_NSID:
 			if rule.action == Replace || rule.action == Set {
 				e.Nsid = "" // make sure it is empty for request
-				result = RewriteDone
+				return RewriteDone
 			}
-			found = true
-			break Option
 		}
 	}
 
 	// add option if not found
-	if !found && (rule.action == Append || rule.action == Set) {
+	if rule.action == Append || rule.action == Set {
 		o.Option = append(o.Option, &dns.EDNS0_NSID{Code: dns.EDNS0NSID, Nsid: ""})
-		result = RewriteDone
+		return RewriteDone
 	}
 
-	return result
+	return RewriteIgnored
 }
 
-// Mode returns the processing mode
+// Mode returns the processing mode.
-func (rule *edns0NsidRule) Mode() string {
+func (rule *edns0NsidRule) Mode() string { return rule.mode }
-	return rule.mode
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *edns0NsidRule) GetResponseRule() ResponseRule {
+func (rule *edns0NsidRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
+
-}
+// Rewrite will alter the request EDNS0 local options.
+func (rule *edns0LocalRule) Rewrite(state request.Request) Result {
+	o := setupEdns0Opt(state.Req)
 
-// Rewrite will alter the request EDNS0 local options
-func (rule *edns0LocalRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
-	result := RewriteIgnored
-	o := setupEdns0Opt(r)
-	found := false
 	for _, s := range o.Option {
-		switch e := s.(type) {
+		if e, ok := s.(*dns.EDNS0_LOCAL); ok {
-		case *dns.EDNS0_LOCAL:
 			if rule.code == e.Code {
 				if rule.action == Replace || rule.action == Set {
 					e.Data = rule.data
-					result = RewriteDone
+					return RewriteDone
 				}
-				found = true
-				break
 			}
 		}
 	}
 
 	// add option if not found
-	if !found && (rule.action == Append || rule.action == Set) {
+	if rule.action == Append || rule.action == Set {
-		var opt dns.EDNS0_LOCAL
+		o.Option = append(o.Option, &dns.EDNS0_LOCAL{Code: rule.code, Data: rule.data})
-		opt.Code = rule.code
+		return RewriteDone
-		opt.Data = rule.data
-		o.Option = append(o.Option, &opt)
-		result = RewriteDone
 	}
 
-	return result
+	return RewriteIgnored
 }
 
-// Mode returns the processing mode
+// Mode returns the processing mode.
-func (rule *edns0LocalRule) Mode() string {
+func (rule *edns0LocalRule) Mode() string { return rule.mode }
-	return rule.mode
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *edns0LocalRule) GetResponseRule() ResponseRule {
+func (rule *edns0LocalRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}
 
 // newEdns0Rule creates an EDNS0 rule of the appropriate type based on the args
 func newEdns0Rule(mode string, args ...string) (Rule, error) {
@@ -145,7 +124,7 @@ func newEdns0Rule(mode string, args ...string) (Rule, error) {
 		if len(args) != 4 {
 			return nil, fmt.Errorf("EDNS0 local rules require exactly three args")
 		}
-		//Check for variable option
+		// Check for variable option.
 		if strings.HasPrefix(args[3], "{") && strings.HasSuffix(args[3], "}") {
 			return newEdns0VariableRule(mode, action, args[2], args[3])
 		}
@@ -194,136 +173,69 @@ func newEdns0VariableRule(mode, action, code, variable string) (*edns0VariableRu
 	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.
+// ruleData returns the data specified by the variable.
-func (rule *edns0VariableRule) ipToWire(family int, ipAddr string) ([]byte, error) {
+func (rule *edns0VariableRule) ruleData(state request.Request) ([]byte, error) {
 
-	switch family {
-	case 1:
-		return net.ParseIP(ipAddr).To4(), nil
-	case 2:
-		return net.ParseIP(ipAddr).To16(), nil
-	}
-	return nil, fmt.Errorf("invalid IP address family (i.e. version) %d", family)
-}
-
-// uint16ToWire writes unit16 to wire/binary format
-func (rule *edns0VariableRule) uint16ToWire(data uint16) []byte {
-	buf := make([]byte, 2)
-	binary.BigEndian.PutUint16(buf, uint16(data))
-	return buf
-}
-
-// portToWire writes port to wire/binary format, 2 bytes
-func (rule *edns0VariableRule) portToWire(portStr string) ([]byte, error) {
-
-	port, err := strconv.ParseUint(portStr, 10, 16)
-	if err != nil {
-		return nil, err
-	}
-	return rule.uint16ToWire(uint16(port)), nil
-}
-
-// Family returns the family of the transport, 1 for IPv4 and 2 for IPv6.
-func (rule *edns0VariableRule) family(ip net.Addr) int {
-	var a net.IP
-	if i, ok := ip.(*net.UDPAddr); ok {
-		a = i.IP
-	}
-	if i, ok := ip.(*net.TCPAddr); ok {
-		a = i.IP
-	}
-	if a.To4() != nil {
-		return 1
-	}
-	return 2
-}
-
-// ruleData returns the data specified by the variable
-func (rule *edns0VariableRule) ruleData(w dns.ResponseWriter, r *dns.Msg) ([]byte, error) {
-
-	req := request.Request{W: w, Req: r}
 	switch rule.variable {
 	case queryName:
-		//Query name is written as ascii string
+		return []byte(state.QName()), nil
-		return []byte(req.QName()), nil
 
 	case queryType:
-		return rule.uint16ToWire(req.QType()), nil
+		return uint16ToWire(state.QType()), nil
 
 	case clientIP:
-		return rule.ipToWire(req.Family(), req.IP())
+		return ipToWire(state.Family(), state.IP())
-
-	case clientPort:
-		return rule.portToWire(req.Port())
-
-	case protocol:
-		// Proto is written as ascii string
-		return []byte(req.Proto()), nil
 
 	case serverIP:
-		ip, _, err := net.SplitHostPort(w.LocalAddr().String())
+		return ipToWire(state.Family(), state.LocalIP())
-		if err != nil {
+
-			ip = w.RemoteAddr().String()
+	case clientPort:
-		}
+		return portToWire(state.Port())
-		return rule.ipToWire(rule.family(w.RemoteAddr()), ip)
 
 	case serverPort:
-		_, port, err := net.SplitHostPort(w.LocalAddr().String())
+		return portToWire(state.LocalPort())
-		if err != nil {
+
-			port = "0"
+	case protocol:
-		}
+		return []byte(state.Proto()), nil
-		return rule.portToWire(port)
 	}
 
 	return nil, fmt.Errorf("unable to extract data for variable %s", rule.variable)
 }
 
-// Rewrite will alter the request EDNS0 local options with specified variables
+// Rewrite will alter the request EDNS0 local options with specified variables.
-func (rule *edns0VariableRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *edns0VariableRule) Rewrite(state request.Request) Result {
-	result := RewriteIgnored
+	data, err := rule.ruleData(state)
-
-	data, err := rule.ruleData(w, r)
 	if err != nil || data == nil {
-		return result
+		return RewriteIgnored
 	}
 
-	o := setupEdns0Opt(r)
+	o := setupEdns0Opt(state.Req)
-	found := false
 	for _, s := range o.Option {
-		switch e := s.(type) {
+		if e, ok := s.(*dns.EDNS0_LOCAL); ok {
-		case *dns.EDNS0_LOCAL:
 			if rule.code == e.Code {
 				if rule.action == Replace || rule.action == Set {
 					e.Data = data
-					result = RewriteDone
+					return RewriteDone
 				}
-				found = true
+				return RewriteIgnored
-				break
 			}
 		}
 	}
 
 	// add option if not found
-	if !found && (rule.action == Append || rule.action == Set) {
+	if rule.action == Append || rule.action == Set {
-		var opt dns.EDNS0_LOCAL
+		o.Option = append(o.Option, &dns.EDNS0_LOCAL{Code: rule.code, Data: data})
-		opt.Code = rule.code
+		return RewriteDone
-		opt.Data = data
-		o.Option = append(o.Option, &opt)
-		result = RewriteDone
 	}
 
-	return result
+	return RewriteIgnored
 }
 
-// Mode returns the processing mode
+// Mode returns the processing mode.
-func (rule *edns0VariableRule) Mode() string {
+func (rule *edns0VariableRule) Mode() string { return rule.mode }
-	return rule.mode
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *edns0VariableRule) GetResponseRule() ResponseRule {
+func (rule *edns0VariableRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}
 
 func isValidVariable(variable string) bool {
 	switch variable {
@@ -353,8 +265,8 @@ func newEdns0SubnetRule(mode, action, v4BitMaskLen, v6BitMaskLen string) (*edns0
 	if err != nil {
 		return nil, err
 	}
-	// Validate V4 length
+	// validate V4 length
-	if v4Len > maxV4BitMaskLen {
+	if v4Len > net.IPv4len*8 {
 		return nil, fmt.Errorf("invalid IPv4 bit mask length %d", v4Len)
 	}
 
@@ -362,8 +274,8 @@ func newEdns0SubnetRule(mode, action, v4BitMaskLen, v6BitMaskLen string) (*edns0
 	if err != nil {
 		return nil, err
 	}
-	//Validate V6 length
+	// validate V6 length
-	if v6Len > maxV6BitMaskLen {
+	if v6Len > net.IPv6len*8 {
 		return nil, fmt.Errorf("invalid IPv6 bit mask length %d", v6Len)
 	}
 
@@ -372,10 +284,8 @@ func newEdns0SubnetRule(mode, action, v4BitMaskLen, v6BitMaskLen string) (*edns0
 }
 
 // fillEcsData sets the subnet data into the ecs option
-func (rule *edns0SubnetRule) fillEcsData(w dns.ResponseWriter, r *dns.Msg, ecs *dns.EDNS0_SUBNET) error {
+func (rule *edns0SubnetRule) fillEcsData(state request.Request, ecs *dns.EDNS0_SUBNET) error {
-
+	family := state.Family()
-	req := request.Request{W: w, Req: r}
-	family := req.Family()
 	if (family != 1) && (family != 2) {
 		return fmt.Errorf("unable to fill data for EDNS0 subnet due to invalid IP family")
 	}
@@ -383,7 +293,7 @@ func (rule *edns0SubnetRule) fillEcsData(w dns.ResponseWriter, r *dns.Msg, ecs *
 	ecs.Family = uint16(family)
 	ecs.SourceScope = 0
 
-	ipAddr := req.IP()
+	ipAddr := state.IP()
 	switch family {
 	case 1:
 		ipv4Mask := net.CIDRMask(int(rule.v4BitMaskLen), 32)
@@ -399,45 +309,38 @@ func (rule *edns0SubnetRule) fillEcsData(w dns.ResponseWriter, r *dns.Msg, ecs *
 	return nil
 }
 
-// Rewrite will alter the request EDNS0 subnet option
+// Rewrite will alter the request EDNS0 subnet option.
-func (rule *edns0SubnetRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *edns0SubnetRule) Rewrite(state request.Request) Result {
-	result := RewriteIgnored
+	o := setupEdns0Opt(state.Req)
-	o := setupEdns0Opt(r)
+
-	found := false
 	for _, s := range o.Option {
-		switch e := s.(type) {
+		if e, ok := s.(*dns.EDNS0_SUBNET); ok {
-		case *dns.EDNS0_SUBNET:
 			if rule.action == Replace || rule.action == Set {
-				if rule.fillEcsData(w, r, e) == nil {
+				if rule.fillEcsData(state, e) == nil {
-					result = RewriteDone
+					return RewriteDone
 				}
 			}
-			found = true
+			return RewriteIgnored
-			break
 		}
 	}
 
 	// add option if not found
-	if !found && (rule.action == Append || rule.action == Set) {
+	if rule.action == Append || rule.action == Set {
-		opt := dns.EDNS0_SUBNET{Code: dns.EDNS0SUBNET}
+		opt := &dns.EDNS0_SUBNET{Code: dns.EDNS0SUBNET}
-		if rule.fillEcsData(w, r, &opt) == nil {
+		if rule.fillEcsData(state, opt) == nil {
-			o.Option = append(o.Option, &opt)
+			o.Option = append(o.Option, opt)
-			result = RewriteDone
+			return RewriteDone
 		}
 	}
 
-	return result
+	return RewriteIgnored
 }
 
 // Mode returns the processing mode
-func (rule *edns0SubnetRule) Mode() string {
+func (rule *edns0SubnetRule) Mode() string { return rule.mode }
-	return rule.mode
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *edns0SubnetRule) GetResponseRule() ResponseRule {
+func (rule *edns0SubnetRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}
 
 // These are all defined actions.
 const (
@@ -456,9 +359,3 @@ const (
 	serverIP   = "{server_ip}"
 	serverPort = "{server_port}"
 )
-
-// Subnet maximum bit mask length
-const (
-	maxV4BitMaskLen = 32
-	maxV6BitMaskLen = 128
-)

plugin/rewrite/name.go

@@ -7,8 +7,7 @@ import (
 	"strings"
 
 	"github.com/coredns/coredns/plugin"
-
+	"github.com/coredns/coredns/request"
-	"github.com/miekg/dns"
 )
 
 type nameRule struct {
@@ -56,47 +55,47 @@ const (
 )
 
 // Rewrite rewrites the current request based upon exact match of the name
-// in the question section of the request
+// in the question section of the request.
-func (rule *nameRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *nameRule) Rewrite(state request.Request) Result {
-	if rule.From == r.Question[0].Name {
+	if rule.From == state.Name() {
-		r.Question[0].Name = rule.To
+		state.Req.Question[0].Name = rule.To
 		return RewriteDone
 	}
 	return RewriteIgnored
 }
 
-// Rewrite rewrites the current request when the name begins with the matching string
+// Rewrite rewrites the current request when the name begins with the matching string.
-func (rule *prefixNameRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *prefixNameRule) Rewrite(state request.Request) Result {
-	if strings.HasPrefix(r.Question[0].Name, rule.Prefix) {
+	if strings.HasPrefix(state.Name(), rule.Prefix) {
-		r.Question[0].Name = rule.Replacement + strings.TrimLeft(r.Question[0].Name, rule.Prefix)
+		state.Req.Question[0].Name = rule.Replacement + strings.TrimLeft(state.Name(), rule.Prefix)
 		return RewriteDone
 	}
 	return RewriteIgnored
 }
 
-// Rewrite rewrites the current request when the name ends with the matching string
+// Rewrite rewrites the current request when the name ends with the matching string.
-func (rule *suffixNameRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *suffixNameRule) Rewrite(state request.Request) Result {
-	if strings.HasSuffix(r.Question[0].Name, rule.Suffix) {
+	if strings.HasSuffix(state.Name(), rule.Suffix) {
-		r.Question[0].Name = strings.TrimRight(r.Question[0].Name, rule.Suffix) + rule.Replacement
+		state.Req.Question[0].Name = strings.TrimRight(state.Name(), rule.Suffix) + rule.Replacement
 		return RewriteDone
 	}
 	return RewriteIgnored
 }
 
 // Rewrite rewrites the current request based upon partial match of the
-// name in the question section of the request
+// name in the question section of the request.
-func (rule *substringNameRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *substringNameRule) Rewrite(state request.Request) Result {
-	if strings.Contains(r.Question[0].Name, rule.Substring) {
+	if strings.Contains(state.Name(), rule.Substring) {
-		r.Question[0].Name = strings.Replace(r.Question[0].Name, rule.Substring, rule.Replacement, -1)
+		state.Req.Question[0].Name = strings.Replace(state.Name(), rule.Substring, rule.Replacement, -1)
 		return RewriteDone
 	}
 	return RewriteIgnored
 }
 
 // Rewrite rewrites the current request when the name in the question
-// section of the request matches a regular expression
+// section of the request matches a regular expression.
-func (rule *regexNameRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *regexNameRule) Rewrite(state request.Request) Result {
-	regexGroups := rule.Pattern.FindStringSubmatch(r.Question[0].Name)
+	regexGroups := rule.Pattern.FindStringSubmatch(state.Name())
 	if len(regexGroups) == 0 {
 		return RewriteIgnored
 	}
@@ -107,7 +106,7 @@ func (rule *regexNameRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
 			s = strings.Replace(s, groupIndexStr, groupValue, -1)
 		}
 	}
-	r.Question[0].Name = s
+	state.Req.Question[0].Name = s
 	return RewriteDone
 }
 
@@ -174,47 +173,23 @@ func newNameRule(nextAction string, args ...string) (Rule, error) {
 }
 
 // Mode returns the processing nextAction
-func (rule *nameRule) Mode() string {
+func (rule *nameRule) Mode() string          { return rule.NextAction }
-	return rule.NextAction
+func (rule *prefixNameRule) Mode() string    { return rule.NextAction }
-}
+func (rule *suffixNameRule) Mode() string    { return rule.NextAction }
-
+func (rule *substringNameRule) Mode() string { return rule.NextAction }
-func (rule *prefixNameRule) Mode() string {
+func (rule *regexNameRule) Mode() string     { return rule.NextAction }
-	return rule.NextAction
-}
-
-func (rule *suffixNameRule) Mode() string {
-	return rule.NextAction
-}
-
-func (rule *substringNameRule) Mode() string {
-	return rule.NextAction
-}
-
-func (rule *regexNameRule) Mode() string {
-	return rule.NextAction
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *nameRule) GetResponseRule() ResponseRule {
+func (rule *nameRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *prefixNameRule) GetResponseRule() ResponseRule {
+func (rule *prefixNameRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *suffixNameRule) GetResponseRule() ResponseRule {
+func (rule *suffixNameRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *substringNameRule) GetResponseRule() ResponseRule {
+func (rule *substringNameRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}
 
 // GetResponseRule return a rule to rewrite the response with.
-func (rule *regexNameRule) GetResponseRule() ResponseRule {
+func (rule *regexNameRule) GetResponseRule() ResponseRule { return rule.ResponseRule }
-	return rule.ResponseRule
-}

plugin/rewrite/reverter.go

@@ -33,8 +33,7 @@ func NewResponseReverter(w dns.ResponseWriter, r *dns.Msg) *ResponseReverter {
 	}
 }
 
-// WriteMsg records the status code and calls the
+// WriteMsg records the status code and calls the underlying ResponseWriter's WriteMsg method.
-// underlying ResponseWriter's WriteMsg method.
 func (r *ResponseReverter) WriteMsg(res *dns.Msg) error {
 	res.Question[0] = r.originalQuestion
 	if r.ResponseRewrite {

plugin/rewrite/rewrite.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/request"
 
 	"github.com/miekg/dns"
 )
@@ -38,8 +39,10 @@ type Rewrite struct {
 // ServeDNS implements the plugin.Handler interface.
 func (rw Rewrite) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
 	wr := NewResponseReverter(w, r)
+	state := request.Request{W: w, Req: r}
+
 	for _, rule := range rw.Rules {
-		switch result := rule.Rewrite(w, r); result {
+		switch result := rule.Rewrite(state); result {
 		case RewriteDone:
 			respRule := rule.GetResponseRule()
 			if respRule.Active == true {
@@ -68,7 +71,7 @@ func (rw Rewrite) Name() string { return "rewrite" }
 // Rule describes a rewrite rule.
 type Rule interface {
 	// Rewrite rewrites the current request.
-	Rewrite(dns.ResponseWriter, *dns.Msg) Result
+	Rewrite(state request.Request) Result
 	// Mode returns the processing mode stop or continue.
 	Mode() string
 	// GetResponseRule returns the rule to rewrite response with, if any.

plugin/rewrite/rewrite_test.go

@@ -482,14 +482,14 @@ func TestRewriteEDNS0LocalVariable(t *testing.T) {
 		},
 		{
 			[]dns.EDNS0{},
-			[]string{"local", "set", "0xffee", "{server_ip}"},
+			[]string{"local", "set", "0xffee", "{server_port}"},
-			[]dns.EDNS0{&dns.EDNS0_LOCAL{Code: 0xffee, Data: []byte{0x7F, 0x00, 0x00, 0x01}}},
+			[]dns.EDNS0{&dns.EDNS0_LOCAL{Code: 0xffee, Data: []byte{0x00, 0x35}}},
 			true,
 		},
 		{
 			[]dns.EDNS0{},
-			[]string{"local", "set", "0xffee", "{server_port}"},
+			[]string{"local", "set", "0xffee", "{server_ip}"},
-			[]dns.EDNS0{&dns.EDNS0_LOCAL{Code: 0xffee, Data: []byte{0x00, 0x35}}},
+			[]dns.EDNS0{&dns.EDNS0_LOCAL{Code: 0xffee, Data: []byte{0x7F, 0x00, 0x00, 0x01}}},
 			true,
 		},
 	}
@@ -498,7 +498,6 @@ func TestRewriteEDNS0LocalVariable(t *testing.T) {
 	for i, tc := range tests {
 		m := new(dns.Msg)
 		m.SetQuestion("example.com.", dns.TypeA)
-		m.Question[0].Qclass = dns.ClassINET
 
 		r, err := newEdns0Rule("stop", tc.args...)
 		if err != nil {
@@ -620,7 +619,6 @@ func TestRewriteEDNS0Subnet(t *testing.T) {
 	for i, tc := range tests {
 		m := new(dns.Msg)
 		m.SetQuestion("example.com.", dns.TypeA)
-		m.Question[0].Qclass = dns.ClassINET
 
 		r, err := newEdns0Rule("stop", tc.args...)
 		if err != nil {

plugin/rewrite/testdata/testfile

@@ -1 +0,0 @@
-empty

plugin/rewrite/type.go

@@ -1,10 +1,12 @@
-// Package rewrite is plugin for rewriting requests internally to something different.
+// Package rewrite is a plugin for rewriting requests internally to something different.
 package rewrite
 
 import (
 	"fmt"
 	"strings"
 
+	"github.com/coredns/coredns/request"
+
 	"github.com/miekg/dns"
 )
 
@@ -28,22 +30,18 @@ func newTypeRule(nextAction string, args ...string) (Rule, error) {
 }
 
 // Rewrite rewrites the the current request.
-func (rule *typeRule) Rewrite(w dns.ResponseWriter, r *dns.Msg) Result {
+func (rule *typeRule) Rewrite(state request.Request) Result {
 	if rule.fromType > 0 && rule.toType > 0 {
-		if r.Question[0].Qtype == rule.fromType {
+		if state.QType() == rule.fromType {
-			r.Question[0].Qtype = rule.toType
+			state.Req.Question[0].Qtype = rule.toType
 			return RewriteDone
 		}
 	}
 	return RewriteIgnored
 }
 
-// Mode returns the processing mode
+// Mode returns the processing mode.
-func (rule *typeRule) Mode() string {
+func (rule *typeRule) Mode() string { return rule.nextAction }
-	return rule.nextAction
-}
 
 // GetResponseRule return a rule to rewrite the response with. Currently not implemented.
-func (rule *typeRule) GetResponseRule() ResponseRule {
+func (rule *typeRule) GetResponseRule() ResponseRule { return ResponseRule{} }
-	return ResponseRule{}
-}

plugin/rewrite/wire.go

@@ -0,0 +1,37 @@
+package rewrite
+
+import (
+	"encoding/binary"
+	"fmt"
+	"net"
+	"strconv"
+)
+
+// ipToWire writes IP address to wire/binary format, 4 or 16 bytes depends on IPV4 or IPV6.
+func ipToWire(family int, ipAddr string) ([]byte, error) {
+
+	switch family {
+	case 1:
+		return net.ParseIP(ipAddr).To4(), nil
+	case 2:
+		return net.ParseIP(ipAddr).To16(), nil
+	}
+	return nil, fmt.Errorf("invalid IP address family (i.e. version) %d", family)
+}
+
+// uint16ToWire writes unit16 to wire/binary format
+func uint16ToWire(data uint16) []byte {
+	buf := make([]byte, 2)
+	binary.BigEndian.PutUint16(buf, uint16(data))
+	return buf
+}
+
+// portToWire writes port to wire/binary format, 2 bytes
+func portToWire(portStr string) ([]byte, error) {
+
+	port, err := strconv.ParseUint(portStr, 10, 16)
+	if err != nil {
+		return nil, err
+	}
+	return uint16ToWire(uint16(port)), nil
+}

request/request.go

@@ -59,6 +59,15 @@ func (r *Request) IP() string {
 	return r.ip
 }
 
+// LocalIP gets the (local) IP address of server handling the request.
+func (r *Request) LocalIP() string {
+	ip, _, err := net.SplitHostPort(r.W.LocalAddr().String())
+	if err != nil {
+		return r.W.LocalAddr().String()
+	}
+	return ip
+}
+
 // Port gets the (remote) port of the client making the request.
 func (r *Request) Port() string {
 	if r.port != "" {