73 lines
1.7 KiB
Go
73 lines
1.7 KiB
Go
package wsutil
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import (
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"io"
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"github.com/gobwas/pool/pbytes"
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"github.com/gobwas/ws"
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)
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// CipherReader implements io.Reader that applies xor-cipher to the bytes read
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// from source.
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// It could help to unmask WebSocket frame payload on the fly.
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type CipherReader struct {
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r io.Reader
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mask [4]byte
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pos int
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}
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// NewCipherReader creates xor-cipher reader from r with given mask.
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func NewCipherReader(r io.Reader, mask [4]byte) *CipherReader {
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return &CipherReader{r, mask, 0}
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}
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// Reset resets CipherReader to read from r with given mask.
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func (c *CipherReader) Reset(r io.Reader, mask [4]byte) {
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c.r = r
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c.mask = mask
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c.pos = 0
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}
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// Read implements io.Reader interface. It applies mask given during
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// initialization to every read byte.
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func (c *CipherReader) Read(p []byte) (n int, err error) {
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n, err = c.r.Read(p)
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ws.Cipher(p[:n], c.mask, c.pos)
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c.pos += n
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return
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}
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// CipherWriter implements io.Writer that applies xor-cipher to the bytes
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// written to the destination writer. It does not modify the original bytes.
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type CipherWriter struct {
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w io.Writer
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mask [4]byte
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pos int
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}
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// NewCipherWriter creates xor-cipher writer to w with given mask.
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func NewCipherWriter(w io.Writer, mask [4]byte) *CipherWriter {
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return &CipherWriter{w, mask, 0}
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}
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// Reset reset CipherWriter to write to w with given mask.
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func (c *CipherWriter) Reset(w io.Writer, mask [4]byte) {
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c.w = w
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c.mask = mask
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c.pos = 0
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}
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// Write implements io.Writer interface. It applies masking during
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// initialization to every sent byte. It does not modify original slice.
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func (c *CipherWriter) Write(p []byte) (n int, err error) {
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cp := pbytes.GetLen(len(p))
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defer pbytes.Put(cp)
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copy(cp, p)
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ws.Cipher(cp, c.mask, c.pos)
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n, err = c.w.Write(cp)
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c.pos += n
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return
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}
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