65 lines
1.2 KiB
Go
65 lines
1.2 KiB
Go
package handshake
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import (
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"bytes"
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"fmt"
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"io"
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)
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// C2S2 is a C2 or S2 packet.
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type C2S2 struct {
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Time uint32
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Time2 uint32
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Random []byte
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Digest []byte
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}
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// Read reads a C2S2.
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func (c *C2S2) Read(r io.Reader, validateSignature bool) error {
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buf := make([]byte, 1536)
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_, err := io.ReadFull(r, buf)
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if err != nil {
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return err
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}
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if validateSignature {
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gap := len(buf) - 32
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digest := hsMakeDigest(c.Digest, buf, gap)
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if !bytes.Equal(buf[gap:gap+32], digest) {
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return fmt.Errorf("unable to validate C2/S2 signature")
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}
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}
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c.Time = uint32(buf[0])<<24 | uint32(buf[1])<<16 | uint32(buf[2])<<8 | uint32(buf[3])
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c.Time2 = uint32(buf[4])<<24 | uint32(buf[5])<<16 | uint32(buf[6])<<8 | uint32(buf[7])
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c.Random = buf[8:]
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return nil
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}
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// Write writes a C2S2.
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func (c C2S2) Write(w io.Writer) error {
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buf := make([]byte, 1536)
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buf[0] = byte(c.Time >> 24)
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buf[1] = byte(c.Time >> 16)
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buf[2] = byte(c.Time >> 8)
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buf[3] = byte(c.Time)
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buf[4] = byte(c.Time2 >> 24)
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buf[5] = byte(c.Time2 >> 16)
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buf[6] = byte(c.Time2 >> 8)
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buf[7] = byte(c.Time2)
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copy(buf[8:], c.Random)
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// signature
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if c.Digest != nil {
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gap := len(buf) - 32
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digest := hsMakeDigest(c.Digest, buf, gap)
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copy(buf[gap:], digest)
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}
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_, err := w.Write(buf)
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return err
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}
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