go.net/ipv4: simplify protocol constants generator

Also updates IANA protocol constants.

R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/14588043

ipv4/gen.go

@@ -100,17 +100,13 @@ type icmpv4Parameters struct {
 	XMLName    xml.Name `xml:"registry"`
 	Title      string   `xml:"title"`
 	Updated    string   `xml:"updated"`
-	Registries []icmpv4ParamRegistry `xml:"registry"`
-}
-
-type icmpv4ParamRegistry struct {
+	Registries []struct {
 		Title   string `xml:"title"`
-	Records []icmpv4ParamRecord `xml:"record"`
-}
-
-type icmpv4ParamRecord struct {
+		Records []struct {
 			Value string `xml:"value"`
 			Descr string `xml:"description"`
+		} `xml:"record"`
+	} `xml:"registry"`
 }
 
 type canonICMPv4ParamRecord struct {
@@ -198,13 +194,11 @@ type protocolNumbers struct {
 	Updated  string   `xml:"updated"`
 	RegTitle string   `xml:"registry>title"`
 	Note     string   `xml:"registry>note"`
-	Records  []protocolRecord `xml:"registry>record"`
-}
-
-type protocolRecord struct {
+	Records  []struct {
 		Value string `xml:"value"`
 		Name  string `xml:"name"`
 		Descr string `xml:"description"`
+	} `xml:"registry>record"`
 }
 
 type canonProtocolRecord struct {

ipv4/gentest.go

@@ -39,7 +39,7 @@ var registries = []struct {
 
 func main() {
 	var bb bytes.Buffer
-	fmt.Fprintf(&bb, "// go run gentv.go\n")
+	fmt.Fprintf(&bb, "// go run gentest.go\n")
 	fmt.Fprintf(&bb, "// GENERATED BY THE COMMAND ABOVE; DO NOT EDIT\n\n")
 	fmt.Fprintf(&bb, "package ipv4_test\n\n")
 	for _, r := range registries {
@@ -90,13 +90,14 @@ type dscpRegistry struct {
 	Updated     string   `xml:"updated"`
 	Note        string   `xml:"note"`
 	RegTitle    string   `xml:"registry>title"`
-	PoolRecords []dscpRecord `xml:"registry>record"`
-	Records     []dscpRecord `xml:"registry>registry>record"`
-}
-
-type dscpRecord struct {
+	PoolRecords []struct {
+		Name  string `xml:"name"`
+		Space string `xml:"space"`
+	} `xml:"registry>record"`
+	Records []struct {
 		Name  string `xml:"name"`
 		Space string `xml:"space"`
+	} `xml:"registry>registry>record"`
 }
 
 type canonDSCPRecord struct {
@@ -150,12 +151,10 @@ type tosTCByte struct {
 	Updated  string   `xml:"updated"`
 	Note     string   `xml:"note"`
 	RegTitle string   `xml:"registry>title"`
-	Records  []tosTCByteRecord `xml:"registry>record"`
-}
-
-type tosTCByteRecord struct {
+	Records  []struct {
 		Binary  string `xml:"binary"`
 		Keyword string `xml:"keyword"`
+	} `xml:"registry>record"`
 }
 
 type canonTOSTCByteRecord struct {

ipv4/iana_test.go

-// go run gentv.go
+// go run gentest.go
 // GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
 
 package ipv4_test
 
-// Differentiated Services Field Codepoints, Updated: 2010-05-11
+// Differentiated Services Field Codepoints (DSCP), Updated: 2013-06-25
 const (
 	DiffServCS0        = 0x0  // CS0
 	DiffServCS1        = 0x20 // CS1