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Implement address truncation as specified in the draft

This commit is contained in:
Miek Gieben 2012-06-01 11:40:57 +02:00
parent 3517449bc9
commit 54519d1a4d
1 changed files with 13 additions and 7 deletions
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20
edns.go
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@ -119,13 +119,13 @@ func (rr *RR_OPT) SetDo() {
rr.Hdr.Ttl = uint32(b1)<<24 | uint32(b2)<<16 | uint32(b3)<<8 | uint32(b4)
}
// EDNS0 defines a EDNS0 Option
// EDNS0 defines an EDNS0 Option.
type EDNS0 interface {
// Option return the option code for the option.
// Option returns the option code for the option.
Option() uint16
// Pack returns the bytes of the option data.
Pack() ([]byte, error)
// Unpack sets the data as found in the packet. Is also sets
// Unpack sets the data as found in the buffer. Is also sets
// the length of the slice as the length of the option data.
Unpack([]byte)
// String returns the string representation of the option.
@ -176,9 +176,11 @@ func (e *EDNS0_SUBNET) Pack() ([]byte, error) {
b[3] = e.SourceScope
switch e.Family {
case 1:
// just copy? TODO (also in msg.go...)
if e.SourceNetmask > net.IPv4len * 8 {
return nil, errors.New("bad netmask")
}
ip := make([]byte, net.IPv4len)
a := e.Address.To4()
a := e.Address.To4().Mask( net.CIDRMask(int(e.SourceNetmask), net.IPv4len * 8) )
for i := 0; i < net.IPv4len; i++ {
if i+1 > len(e.Address) {
break
@ -187,12 +189,16 @@ func (e *EDNS0_SUBNET) Pack() ([]byte, error) {
}
b = append(b, ip...)
case 2:
if e.SourceNetmask > net.IPv6len * 8 {
return nil, errors.New("bad netmask")
}
ip := make([]byte, net.IPv6len)
a := e.Address.Mask( net.CIDRMask(int(e.SourceNetmask), net.IPv6len * 8) )
for i := 0; i < net.IPv6len; i++ {
if i+1 > len(e.Address) {
break
}
ip[i] = e.Address[i]
ip[i] = a[i]
}
b = append(b, ip...)
default:
@ -202,7 +208,7 @@ func (e *EDNS0_SUBNET) Pack() ([]byte, error) {
}
func (e *EDNS0_SUBNET) Unpack(b []byte) {
// TODO: length of b
// TODO: length of b (overflow)
e.Family, _ = unpackUint16(b, 0)
e.SourceNetmask = b[2]
e.SourceScope = b[3]