70 lines
2.0 KiB
Go
70 lines
2.0 KiB
Go
|
package sctp
|
||
|
|
|
||
|
|
import (
|
||
|
|
"encoding/binary"
|
||
|
|
"encoding/hex"
|
||
|
|
"errors"
|
||
|
|
"fmt"
|
||
|
|
)
|
||
|
|
|
||
|
|
type paramHeader struct {
|
||
|
|
typ paramType
|
||
|
|
len int
|
||
|
|
raw []byte
|
||
|
|
}
|
||
|
|
|
||
|
|
const (
|
||
|
|
paramHeaderLength = 4
|
||
|
|
)
|
||
|
|
|
||
|
|
var (
|
||
|
|
errParamHeaderTooShort = errors.New("param header too short")
|
||
|
|
errParamHeaderSelfReportedLengthShorter = errors.New("param self reported length is shorter than header length")
|
||
|
|
errParamHeaderSelfReportedLengthLonger = errors.New("param self reported length is longer than header length")
|
||
|
|
errParamHeaderParseFailed = errors.New("failed to parse param type")
|
||
|
|
)
|
||
|
|
|
||
|
|
func (p *paramHeader) marshal() ([]byte, error) {
|
||
|
|
paramLengthPlusHeader := paramHeaderLength + len(p.raw)
|
||
|
|
|
||
|
|
rawParam := make([]byte, paramLengthPlusHeader)
|
||
|
|
binary.BigEndian.PutUint16(rawParam[0:], uint16(p.typ))
|
||
|
|
binary.BigEndian.PutUint16(rawParam[2:], uint16(paramLengthPlusHeader))
|
||
|
|
copy(rawParam[paramHeaderLength:], p.raw)
|
||
|
|
|
||
|
|
return rawParam, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *paramHeader) unmarshal(raw []byte) error {
|
||
|
|
if len(raw) < paramHeaderLength {
|
||
|
|
return errParamHeaderTooShort
|
||
|
|
}
|
||
|
|
|
||
|
|
paramLengthPlusHeader := binary.BigEndian.Uint16(raw[2:])
|
||
|
|
if int(paramLengthPlusHeader) < paramHeaderLength {
|
||
|
|
return fmt.Errorf("%w: param self reported length (%d) shorter than header length (%d)", errParamHeaderSelfReportedLengthShorter, int(paramLengthPlusHeader), paramHeaderLength)
|
||
|
|
}
|
||
|
|
if len(raw) < int(paramLengthPlusHeader) {
|
||
|
|
return fmt.Errorf("%w: param length (%d) shorter than its self reported length (%d)", errParamHeaderSelfReportedLengthLonger, len(raw), int(paramLengthPlusHeader))
|
||
|
|
}
|
||
|
|
|
||
|
|
typ, err := parseParamType(raw[0:])
|
||
|
|
if err != nil {
|
||
|
|
return fmt.Errorf("%w: %v", errParamHeaderParseFailed, err)
|
||
|
|
}
|
||
|
|
p.typ = typ
|
||
|
|
p.raw = raw[paramHeaderLength:paramLengthPlusHeader]
|
||
|
|
p.len = int(paramLengthPlusHeader)
|
||
|
|
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *paramHeader) length() int {
|
||
|
|
return p.len
|
||
|
|
}
|
||
|
|
|
||
|
|
// String makes paramHeader printable
|
||
|
|
func (p paramHeader) String() string {
|
||
|
|
return fmt.Sprintf("%s (%d): %s", p.typ, p.len, hex.Dump(p.raw))
|
||
|
|
}
|