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soypat
45 lines
898 B
Go
45 lines
898 B
Go
package internal
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import (
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"encoding/binary"
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"errors"
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)
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var (
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errUnsupportedIP = errors.New("unsupported IP version")
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errInvalidIPVersionToSetAddr = errors.New("invalid ip version to setDstAddr")
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)
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func GetIPSourceAddr(buf []byte) (addr []byte, id uint16, err error) {
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version := buf[0] >> 4
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switch version { //
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case 4:
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addr = buf[12:16]
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id = binary.BigEndian.Uint16(buf[4:6])
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case 6:
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addr = buf[8:24]
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default:
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err = errUnsupportedIP
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}
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return addr, id, err
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}
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func SetIPDestinationAddr(buf []byte, id uint16, addr []byte) (err error) {
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var dstaddr []byte
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version := buf[0] >> 4
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switch version {
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case 4:
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dstaddr = buf[16:20]
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binary.BigEndian.PutUint16(buf[4:6], id)
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case 6:
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dstaddr = buf[24:40]
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default:
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err = errUnsupportedIP
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}
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if err == nil && len(dstaddr) != len(addr) {
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return errInvalidIPVersionToSetAddr
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}
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copy(dstaddr, addr)
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return nil
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}
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