71 lines
2.2 KiB
Go
71 lines
2.2 KiB
Go
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// Package srtp implements Secure Real-time Transport Protocol
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package srtp
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import (
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"github.com/pion/rtp"
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)
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func (c *Context) decryptRTP(dst, ciphertext []byte, header *rtp.Header, headerLen int) ([]byte, error) {
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s := c.getSRTPSSRCState(header.SSRC)
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markAsValid, ok := s.replayDetector.Check(uint64(header.SequenceNumber))
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if !ok {
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return nil, &errorDuplicated{
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Proto: "srtp", SSRC: header.SSRC, Index: uint32(header.SequenceNumber),
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}
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}
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dst = growBufferSize(dst, len(ciphertext)-c.cipher.authTagLen())
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roc, updateROC := s.nextRolloverCount(header.SequenceNumber)
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dst, err := c.cipher.decryptRTP(dst, ciphertext, header, headerLen, roc)
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if err != nil {
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return nil, err
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}
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markAsValid()
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updateROC()
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return dst, nil
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}
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// DecryptRTP decrypts a RTP packet with an encrypted payload
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func (c *Context) DecryptRTP(dst, encrypted []byte, header *rtp.Header) ([]byte, error) {
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if header == nil {
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header = &rtp.Header{}
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}
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headerLen, err := header.Unmarshal(encrypted)
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if err != nil {
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return nil, err
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}
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return c.decryptRTP(dst, encrypted, header, headerLen)
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}
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// EncryptRTP marshals and encrypts an RTP packet, writing to the dst buffer provided.
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// If the dst buffer does not have the capacity to hold `len(plaintext) + 10` bytes, a new one will be allocated and returned.
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// If a rtp.Header is provided, it will be Unmarshaled using the plaintext.
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func (c *Context) EncryptRTP(dst []byte, plaintext []byte, header *rtp.Header) ([]byte, error) {
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if header == nil {
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header = &rtp.Header{}
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}
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headerLen, err := header.Unmarshal(plaintext)
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if err != nil {
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return nil, err
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}
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return c.encryptRTP(dst, header, plaintext[headerLen:])
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}
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// encryptRTP marshals and encrypts an RTP packet, writing to the dst buffer provided.
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// If the dst buffer does not have the capacity, a new one will be allocated and returned.
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// Similar to above but faster because it can avoid unmarshaling the header and marshaling the payload.
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func (c *Context) encryptRTP(dst []byte, header *rtp.Header, payload []byte) (ciphertext []byte, err error) {
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s := c.getSRTPSSRCState(header.SSRC)
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roc, updateROC := s.nextRolloverCount(header.SequenceNumber)
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updateROC()
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return c.cipher.encryptRTP(dst, header, payload, roc)
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}
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