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package sctp
import (
"encoding/binary"
"errors"
"fmt"
)
type hmacAlgorithm uint16
const (
hmacResv1 hmacAlgorithm = 0
hmacSHA128 = 1
hmacResv2 hmacAlgorithm = 2
hmacSHA256 hmacAlgorithm = 3
)
// ErrInvalidAlgorithmType is returned if unknown auth algorithm is specified.
var ErrInvalidAlgorithmType = errors.New("invalid algorithm type")
func (c hmacAlgorithm) String() string {
switch c {
case hmacResv1:
return "HMAC Reserved (0x00)"
case hmacSHA128:
return "HMAC SHA-128"
case hmacResv2:
return "HMAC Reserved (0x02)"
case hmacSHA256:
return "HMAC SHA-256"
default:
return fmt.Sprintf("Unknown HMAC Algorithm type: %d", c)
}
}
type paramRequestedHMACAlgorithm struct {
paramHeader
availableAlgorithms []hmacAlgorithm
}
func (r *paramRequestedHMACAlgorithm) marshal() ([]byte, error) {
r.typ = reqHMACAlgo
r.raw = make([]byte, len(r.availableAlgorithms)*2)
i := 0
for _, a := range r.availableAlgorithms {
binary.BigEndian.PutUint16(r.raw[i:], uint16(a))
i += 2
}
return r.paramHeader.marshal()
}
func (r *paramRequestedHMACAlgorithm) unmarshal(raw []byte) (param, error) {
err := r.paramHeader.unmarshal(raw)
if err != nil {
return nil, err
}
i := 0
for i < len(r.raw) {
a := hmacAlgorithm(binary.BigEndian.Uint16(r.raw[i:]))
switch a {
case hmacSHA128:
fallthrough
case hmacSHA256:
r.availableAlgorithms = append(r.availableAlgorithms, a)
default:
return nil, fmt.Errorf("%w: %v", ErrInvalidAlgorithmType, a)
}
i += 2
}
return r, nil
}
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