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