* Change EDNS_EXPIRE field to support zero length option data (Resolves #1292) As per [RFC7134](https://datatracker.ietf.org/doc/html/rfc7314#section-2) the Expire Option in queries should be zero-length. In the current implementation the field is uint32 which always instatiates 4bytes for that field when packing to wire format. For that reason we change the field to []uint8 so it can support 0-length and 4-byte length option data. * addressed comments * addressed comments * make change backwards compatible * add comment for Empty field
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05140a3136
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16
edns.go
16
edns.go
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@ -584,14 +584,17 @@ func (e *EDNS0_N3U) copy() EDNS0 { return &EDNS0_N3U{e.Code, e.AlgCode} }
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type EDNS0_EXPIRE struct {
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Code uint16 // Always EDNS0EXPIRE
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Expire uint32
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Empty bool // Empty is used to signal an empty Expire option in a backwards compatible way, it's not used on the wire.
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}
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// Option implements the EDNS0 interface.
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func (e *EDNS0_EXPIRE) Option() uint16 { return EDNS0EXPIRE }
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func (e *EDNS0_EXPIRE) String() string { return strconv.FormatUint(uint64(e.Expire), 10) }
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func (e *EDNS0_EXPIRE) copy() EDNS0 { return &EDNS0_EXPIRE{e.Code, e.Expire} }
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func (e *EDNS0_EXPIRE) copy() EDNS0 { return &EDNS0_EXPIRE{e.Code, e.Expire, e.Empty} }
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func (e *EDNS0_EXPIRE) pack() ([]byte, error) {
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if e.Empty {
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return []byte{}, nil
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}
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b := make([]byte, 4)
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binary.BigEndian.PutUint32(b, e.Expire)
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return b, nil
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@ -600,15 +603,24 @@ func (e *EDNS0_EXPIRE) pack() ([]byte, error) {
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func (e *EDNS0_EXPIRE) unpack(b []byte) error {
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if len(b) == 0 {
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// zero-length EXPIRE query, see RFC 7314 Section 2
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e.Empty = true
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return nil
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}
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if len(b) < 4 {
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return ErrBuf
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}
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e.Expire = binary.BigEndian.Uint32(b)
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e.Empty = false
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return nil
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}
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func (e *EDNS0_EXPIRE) String() (s string) {
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if e.Empty {
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return ""
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}
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return strconv.FormatUint(uint64(e.Expire), 10)
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}
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// The EDNS0_LOCAL option is used for local/experimental purposes. The option
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// code is recommended to be within the range [EDNS0LOCALSTART, EDNS0LOCALEND]
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// (RFC6891), although any unassigned code can actually be used. The content of
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