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Remove len(msg) in favor of a variable with that value

This commit is contained in:
Miek Gieben 2011-08-09 10:54:58 +02:00
parent 1053090121
commit 100f8ef7eb
1 changed files with 62 additions and 60 deletions
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122
msg.go
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@ -292,16 +292,17 @@ Loop:
// slices and other (often anonymous) structs.
func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool) {
for i := 0; i < val.NumField(); i++ {
f := val.Type().Field(i)
// f := val.Type().Field(i)
lenmsg := len(msg)
switch fv := val.Field(i); fv.Kind() {
default:
//fmt.Fprintf(os.Stderr, "dns: unknown packing type %v\n", f.Type)
return len(msg), false
return lenmsg, false
case reflect.Slice:
switch f.Tag {
switch val.Type().Field(i).Tag {
default:
//fmt.Fprintf(os.Stderr, "dns: unknown packing slice tag %v\n", f.Tag)
return len(msg), false
return lenmsg, false
case "OPT": // edns
for j := 0; j < val.Field(i).Len(); j++ {
element := val.Field(i).Index(j)
@ -310,7 +311,7 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
h, e := hex.DecodeString(string(element.Field(1).String()))
if e != nil {
//fmt.Fprintf(os.Stderr, "dns: failure packing OTP")
return len(msg), false
return lenmsg, false
}
data := string(h)
// Option Code
@ -326,9 +327,9 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
case "A":
// It must be a slice of 4, even if it is 16, we encode
// only the first 4
if off+net.IPv4len > len(msg) {
if off+net.IPv4len > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow packing A")
return len(msg), false
return lenmsg, false
}
if fv.Len() == net.IPv6len {
msg[off] = byte(fv.Index(12).Uint())
@ -343,9 +344,9 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
}
off += net.IPv4len
case "AAAA":
if fv.Len() > net.IPv6len || off+fv.Len() > len(msg) {
if fv.Len() > net.IPv6len || off+fv.Len() > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow packing AAAA")
return len(msg), false
return lenmsg, false
}
for j := 0; j < net.IPv6len; j++ {
msg[off] = byte(fv.Index(j).Uint())
@ -361,25 +362,25 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
case reflect.Struct:
off, ok = packStructValue(fv, msg, off)
case reflect.Uint8:
if off+1 > len(msg) {
if off+1 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow packing uint8")
return len(msg), false
return lenmsg, false
}
msg[off] = byte(fv.Uint())
off++
case reflect.Uint16:
if off+2 > len(msg) {
if off+2 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow packing uint16")
return len(msg), false
return lenmsg, false
}
i := fv.Uint()
msg[off] = byte(i >> 8)
msg[off+1] = byte(i)
off += 2
case reflect.Uint32:
if off+4 > len(msg) {
if off+4 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow packing uint32")
return len(msg), false
return lenmsg, false
}
i := fv.Uint()
msg[off] = byte(i >> 24)
@ -389,9 +390,9 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
off += 4
case reflect.Uint64:
// Only used in TSIG, where it stops at 48 bits, so we discard the upper 16
if off+6 > len(msg) {
if off+6 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow packing uint64")
return len(msg), false
return lenmsg, false
}
i := fv.Uint()
msg[off] = byte(i >> 40)
@ -405,15 +406,15 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
// There are multiple string encodings.
// The tag distinguishes ordinary strings from domain names.
s := fv.String()
switch f.Tag {
switch val.Type().Field(i).Tag {
default:
//fmt.Fprintf(os.Stderr, "dns: unknown packing string tag %v", f.Tag)
return len(msg), false
return lenmsg, false
case "base32":
b32, err := packBase32([]byte(s))
if err != nil {
//fmt.Fprintf(os.Stderr, "dns: overflow packing base32")
return len(msg), false
return lenmsg, false
}
copy(msg[off:off+len(b32)], b32)
off += len(b32)
@ -421,7 +422,7 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
b64, err := packBase64([]byte(s))
if err != nil {
//fmt.Fprintf(os.Stderr, "dns: overflow packing base64")
return len(msg), false
return lenmsg, false
}
copy(msg[off:off+len(b64)], b64)
off += len(b64)
@ -429,7 +430,7 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
off, ok = packDomainName(s, msg, off)
if !ok {
//fmt.Fprintf(os.Stderr, "dns: overflow packing domain-name")
return len(msg), false
return lenmsg, false
}
case "size-hex":
fallthrough
@ -438,7 +439,7 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
h, e := hex.DecodeString(s)
if e != nil {
//fmt.Fprintf(os.Stderr, "dns: overflow packing (size-)hex string")
return len(msg), false
return lenmsg, false
}
copy(msg[off:off+hex.DecodedLen(len(s))], h)
off += hex.DecodedLen(len(s))
@ -453,7 +454,7 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
fallthrough
case "":
// Counted string: 1 byte length.
if len(s) > 255 || off+1+len(s) > len(msg) {
if len(s) > 255 || off+1+len(s) > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow packing string")
return len(msg), false
}
@ -482,34 +483,35 @@ func packStruct(any interface{}, msg []byte, off int) (off1 int, ok bool) {
// Same restrictions as packStructValue.
func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool) {
for i := 0; i < val.NumField(); i++ {
f := val.Type().Field(i)
// f := val.Type().Field(i)
lenmsg := len(msg)
switch fv := val.Field(i); fv.Kind() {
default:
//fmt.Fprintf(os.Stderr, "dns: unknown unpacking type %v", f.Type)
return len(msg), false
return lenmsg, false
case reflect.Slice:
switch f.Tag {
switch val.Type().Field(i).Tag {
default:
//fmt.Fprintf(os.Stderr, "dns: unknown unpacking slice tag %v", f.Tag)
return len(msg), false
return lenmsg, false
case "A":
if off+net.IPv4len > len(msg) {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking A")
return len(msg), false
return lenmsg, false
}
fv.Set(reflect.ValueOf( net.IPv4(msg[off], msg[off+1], msg[off+2], msg[off+3]) ))
off += net.IPv4len
case "AAAA":
if off+net.IPv6len > len(msg) {
if off+net.IPv6len > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking AAAA")
return len(msg), false
return lenmsg, false
}
fv.Set(reflect.ValueOf( net.IP{msg[off], msg[off+1], msg[off+2], msg[off+3], msg[off+4],
msg[off+5], msg[off+6], msg[off+7], msg[off+8], msg[off+9], msg[off+10],
msg[off+11], msg[off+12], msg[off+13], msg[off+14], msg[off+15]} ))
off += net.IPv6len
case "OPT": // EDNS
if off+2 > len(msg) {
if off+2 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking OPT")
// No room for anything else
break
@ -517,26 +519,26 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok boo
opt := make([]Option, 1)
opt[0].Code, off = unpackUint16(msg, off)
optlen, off1 := unpackUint16(msg, off)
if off1+int(optlen) > len(msg) {
if off1+int(optlen) > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking OPT")
return len(msg), false
return lenmsg, false
}
opt[0].Data = hex.EncodeToString(msg[off1 : off1+int(optlen)])
fv.Set(reflect.ValueOf(opt))
off = off1 + int(optlen)
case "NSEC": // NSEC/NSEC3
if off+1 > len(msg) {
if off+1 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking NSEC")
return len(msg), false
return lenmsg, false
}
// Fix multple windows TODO(mg)
nsec := make([]uint16, 256) // use append TODO(mg)
ni := 0
window := int(msg[off])
blocks := int(msg[off+1])
if off+blocks > len(msg) {
if off+blocks > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking NSEC")
return len(msg), false
return lenmsg, false
}
if blocks == 0 {
// Nothing encoded in this window
@ -590,43 +592,43 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok boo
case reflect.Struct:
off, ok = unpackStructValue(fv, msg, off)
case reflect.Uint8:
if off+1 > len(msg) {
if off+1 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking uint8")
return len(msg), false
return lenmsg, false
}
fv.SetUint( uint64(uint8(msg[off])) )
off++
case reflect.Uint16:
var i uint16
if off+2 > len(msg) {
if off+2 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking uint16")
return len(msg), false
return lenmsg, false
}
i, off = unpackUint16(msg, off)
fv.SetUint(uint64(i))
case reflect.Uint32:
if off+4 > len(msg) {
if off+4 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking uint32")
return len(msg), false
return lenmsg, false
}
fv.SetUint(uint64( uint32(msg[off])<<24 | uint32(msg[off+1])<<16 | uint32(msg[off+2])<<8 | uint32(msg[off+3]) ))
off += 4
case reflect.Uint64:
// This is *only* used in TSIG where the last 48 bits are occupied
// So for now, assume a uint48 (6 bytes)
if off+6 > len(msg) {
if off+6 > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: overflow unpacking uint64")
return len(msg), false
return lenmsg, false
}
fv.SetUint(uint64( uint64(msg[off])<<40 | uint64(msg[off+1])<<32 | uint64(msg[off+2])<<24 | uint64(msg[off+3])<<16 |
uint64(msg[off+4])<<8 | uint64(msg[off+5]) ))
off += 6
case reflect.String:
var s string
switch f.Tag {
switch val.Type().Field(i).Tag {
default:
//fmt.Fprintf(os.Stderr, "dns: unknown unpacking string tag %v", f.Tag)
return len(msg), false
return lenmsg, false
case "hex":
// Rest of the RR is hex encoded, network order an issue here?
rdlength := int(val.FieldByName("Hdr").FieldByName("Rdlength").Uint())
@ -668,21 +670,21 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok boo
s, off, ok = unpackDomainName(msg, off)
if !ok {
//fmt.Fprintf(os.Stderr, "dns: failure unpacking domain-name")
return len(msg), false
return lenmsg, false
}
case "size-base32":
var size int
switch val.Type().Name() {
case "RR_NSEC3":
switch f.Name {
switch val.Type().Field(i).Name {
case "NextDomain":
name := val.FieldByName("HashLength")
size = int(name.Uint())
}
}
if off+size > len(msg) {
if off+size > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: failure unpacking size-base32 string")
return len(msg), false
return lenmsg, false
}
s = unpackBase32(msg[off : off+size])
off += size
@ -691,7 +693,7 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok boo
var size int
switch val.Type().Name() {
case "RR_NSEC3":
switch f.Name {
switch val.Type().Field(i).Name {
case "Salt":
name := val.FieldByName("SaltLength")
size = int(name.Uint())
@ -700,7 +702,7 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok boo
size = int(name.Uint())
}
case "RR_TSIG":
switch f.Name {
switch val.Type().Field(i).Name {
case "MAC":
name := val.FieldByName("MACSize")
size = int(name.Uint())
@ -709,9 +711,9 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok boo
size = int(name.Uint())
}
}
if off+size > len(msg) {
if off+size > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: failure unpacking size-hex string")
return len(msg), false
return lenmsg, false
}
s = hex.EncodeToString(msg[off : off+size])
off += size
@ -719,9 +721,9 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok boo
// 1 or multiple txt pieces
rdlength := int(val.FieldByName("Hdr").FieldByName("Rdlength").Uint())
Txt:
if off >= len(msg) || off+1+int(msg[off]) > len(msg) {
if off >= lenmsg || off+1+int(msg[off]) > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: failure unpacking txt string")
return len(msg), false
return lenmsg, false
}
n := int(msg[off])
off++
@ -734,9 +736,9 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok boo
goto Txt
}
case "":
if off >= len(msg) || off+1+int(msg[off]) > len(msg) {
if off >= lenmsg || off+1+int(msg[off]) > lenmsg {
//fmt.Fprintf(os.Stderr, "dns: failure unpacking string")
return len(msg), false
return lenmsg, false
}
n := int(msg[off])
off++