feat: add UDP audio transport with OCB-AES128 encryption
Add native UDP support for audio transport, which provides much lower latency than tunneling audio over TCP. The implementation: - Adds OCB-AES128 encryption (RFC 7253) for UDP audio packets, as required by the Mumble protocol. - Implements the CryptSetup handler to receive encryption keys and nonces from the server. - Opens a UDP socket to the server after TCP connection and starts reading encrypted audio once the CryptSetup is received. - Modifies WriteAudio to try UDP first with automatic fallback to the existing TCP tunnel when UDP is unavailable or encryption is not set up. - Adds UDP ping packets to keep NAT bindings alive. - Cleans up the UDP connection on disconnect. The OCB implementation is a self-contained pure-Go implementation using only crypto/aes and crypto/cipher from the standard library.
This commit is contained in:
Brandon McGinty (deepseek)
committed by
Brandon McGinty
Brandon McGinty
parent
3e98e93cfb
commit
6a6f94a11d
@@ -75,7 +75,7 @@ func (a AudioBuffer) writeAudio(client *Client, seq int64, final bool) error {
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if target := client.VoiceTarget; target != nil {
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targetID = byte(target.ID)
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}
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return client.Conn.WriteAudio(byte(4), targetID, seq, final, raw, nil, nil, nil)
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return client.WriteAudio(byte(4), targetID, seq, final, raw, nil, nil, nil)
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}
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// AudioPacket contains incoming audio samples and information.
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@@ -68,6 +68,12 @@ type Client struct {
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// will disable voice targeting (i.e. switch back to regular speaking).
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VoiceTarget *VoiceTarget
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// UDP transport for audio (lower latency than TCP-tunneled audio).
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udpConn *net.UDPConn
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udpActive bool
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cryptOut cryptState // client→server encryption
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cryptIn cryptState // server→client encryption
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state uint32
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// volatile is held by the client when the internal data structures are being
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@@ -164,6 +170,10 @@ func DialWithDialer(dialer *net.Dialer, config *Config, tlsConfig *tls.Config) (
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return nil, err
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}
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// Start UDP transport for lower-latency audio. This is best-effort;
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// if UDP fails, audio falls back to TCP tunneling.
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client.startUDP()
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return client, nil
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}
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}
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@@ -245,6 +255,13 @@ func (c *Client) readRoutine() {
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wasSynced := c.State() == StateSynced
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atomic.StoreUint32(&c.state, uint32(StateDisconnected))
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close(c.end)
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// Clean up UDP connection
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if c.udpConn != nil {
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c.udpConn.Close()
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c.udpConn = nil
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}
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if wasSynced {
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c.Config.Listeners.onDisconnect(&c.disconnectEvent)
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}
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@@ -297,6 +314,17 @@ func (c *Client) EnableStereoEncoder() {
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c.useStereoEncoder = true
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}
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// WriteAudio writes an audio packet, preferring UDP when encryption is
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// set up. Falls back to TCP-tunneled audio when UDP is unavailable.
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func (c *Client) WriteAudio(format, target byte, sequence int64, final bool, data []byte, X, Y, Z *float32) error {
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// Try UDP first
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if sent, err := c.WriteAudioUDP(format, target, sequence, final, data, X, Y, Z); sent {
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return err
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}
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// Fall back to TCP tunnel
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return c.Conn.WriteAudio(format, target, sequence, final, data, X, Y, Z)
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}
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// DisableStereoEncoder switches back to mono encoding for voice and
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// resets the stereo encoder so stale state does not bleed into the
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// next file playback.
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@@ -0,0 +1,402 @@
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package gumble
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import (
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"crypto/aes"
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"crypto/cipher"
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"encoding/binary"
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"errors"
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"sync"
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"git.stormux.org/storm/barnard/gumble/gumble/MumbleProto"
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"google.golang.org/protobuf/proto"
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)
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// ocbEncrypt performs OCB-AES128 encryption as required by the Mumble UDP
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// protocol. It encrypts plaintext in-place (output overwrites input) and
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// appends a 16-byte authentication tag.
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//
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// key must be 16 bytes (AES-128).
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// nonce must be 12 bytes.
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// ad is optional associated data that is authenticated but not encrypted.
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func ocbEncrypt(key, nonce, plaintext, ad []byte) ([]byte, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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return ocbCrypt(block, nonce, plaintext, ad, true)
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}
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// ocbDecrypt performs OCB-AES128 decryption. The last 16 bytes of ciphertext
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// are the authentication tag.
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func ocbDecrypt(key, nonce, ciphertext, ad []byte) ([]byte, error) {
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if len(ciphertext) < 16 {
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return nil, errors.New("gumble: ciphertext too short for OCB tag")
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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return ocbCrypt(block, nonce, ciphertext, ad, false)
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}
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// ocbCrypt implements OCB encryption/decryption per RFC 7253.
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// The tag is the last 16 bytes of the output (for encrypt) or input (for decrypt).
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func ocbCrypt(block cipher.Block, nonce, data, ad []byte, encrypt bool) ([]byte, error) {
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if len(nonce) < 1 || len(nonce) > 15 {
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return nil, errors.New("gumble: OCB nonce must be 1-15 bytes")
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}
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blockSize := block.BlockSize() // 16 for AES
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// Number of full 16-byte blocks in the plaintext/ciphertext.
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// The last block may be partial.
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tagLen := blockSize
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var m int
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if encrypt {
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m = (len(data) + blockSize - 1) / blockSize
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} else {
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if len(data) < tagLen {
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return nil, errors.New("gumble: ciphertext too short")
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}
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m = (len(data) - tagLen + blockSize - 1) / blockSize
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}
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out := make([]byte, 0, len(data))
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var offset [16]byte
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var checksum [16]byte
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// --- Compute initial offset (nonce-based) ---
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// Bottom = bit string of length 128-q where q = len(nonce)*8
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// Stretch = Bottom || (Bottom[1..128] XOR Bottom[1..129-q]) || Bottom[129-q]
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// Offset = Stretch[1..128] XOR nonce || 0^{128-q}
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// Build bottom: taglen - nonce_len_in_bytes bits of 0, then 1, then nonce
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// Working with bytes:
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bottom := make([]byte, blockSize)
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q := len(nonce) * 8
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bottomByte := (blockSize - len(nonce)) - 1 // byte index for the 1 bit
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if q%8 != 0 {
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// nonce length is not a multiple of bytes - Mumble always uses 12-byte nonces
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// but we handle the general case
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}
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copy(bottom[blockSize-len(nonce):], nonce)
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bottom[bottomByte] = 0x01 // set the "1" bit after the zero padding
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// Stretch = bottom || (bottom[1..15] ^ bottom[0..14] shifted)
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stretch := make([]byte, blockSize+8)
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copy(stretch, bottom)
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// Compute the XOR for bits 1..128 of bottom (i.e., bottom[1:16])
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// with bottom shifted left by (q mod 8?) bits for fractional bytes.
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// For 12-byte nonce: q=96, q/8=12, q%8=0, so it's byte-aligned.
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// shift = bottom[0..15] >> (8 - (q%8)) but since q%8==0, it's bottom shifted
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// by 0 bits, i.e., just bottom.
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// For byte-aligned nonce: stretch[1..16] XOR bottom
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// bottom shift: need to shift bottom right by nbits where nbits = 8
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// Actually for 12-byte nonce: 4 zero bytes, 1-bit, then 12 byte nonce
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// stretch[1..16] is bottom[1..16]
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// bottom[1..16] shifted: for byte alignment, just bottom[1:] followed by 0
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shift := byte(8)
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for i := 1; i < blockSize+8; i++ {
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// bit 0 of shift-register: b[i-1] >> (8-shift)
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// bits 1..7 of shift-register: b[i] << shift | b[i-1] >> (8-shift)
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if i < blockSize {
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stretch[i] ^= (bottom[i-1] << shift) | (bottom[i] >> (8 - shift))
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} else if i == blockSize {
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stretch[i] ^= bottom[i-1] << shift
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}
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}
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// Offset = stretch[1..16] XOR (nonce || 0*)
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offsetSlice := stretch[1 : 1+blockSize]
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copy(offset[:], offsetSlice)
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for i := 0; i < len(nonce); i++ {
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offset[i] ^= nonce[i]
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}
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// --- Process blocks ---
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for i := 1; i <= m; i++ {
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// Update offset: offset = offset XOR stretch[1+n trailing zeros(n)]
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ntz := ntz(i)
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start := 1 + ntz
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if start+blockSize > len(stretch) {
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break
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}
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for j := 0; j < blockSize; j++ {
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offset[j] ^= stretch[start+j]
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}
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var blockData [16]byte
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if encrypt {
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if i == m {
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// Last block, possibly partial
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lastLen := len(data) - (i-1)*blockSize
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copy(blockData[:], data[(i-1)*blockSize:])
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// Encrypt offset to get pad
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var pad [16]byte
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block.Encrypt(pad[:], offset[:])
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// XOR partial block with pad
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for j := 0; j < lastLen; j++ {
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blockData[j] ^= pad[j]
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}
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// Checksum includes the padded last block
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for j := 0; j < blockSize; j++ {
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if j < lastLen {
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checksum[j] ^= data[(i-1)*blockSize+j]
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} else {
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// Zero-pad: checksum XOR with pad[j] (since plaintext is 0)
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// Actually, checksum ^= plaintext_padded where padding is pad[j]
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// plaintext_padded[j] = 0 for j >= lastLen
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// For OCB, the last block of checksum uses:
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// len(0^*) || C* where C* = first block of pad XOR'd appropriately
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// Simpler: checksum XOR (plaintext_padded XOR pad) so we
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// compute the padded plaintext
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}
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}
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// Actually, let me handle this more simply:
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// For the last partial block, we need to update checksum
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// with the padded plaintext.
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// padded = plaintext || pad[lastLen:]
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// checksum ^= padded
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// Rebuild padded
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var padded [16]byte
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copy(padded[:], data[(i-1)*blockSize:])
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for j := lastLen; j < blockSize; j++ {
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padded[j] = pad[j]
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}
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for j := 0; j < blockSize; j++ {
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checksum[j] ^= padded[j]
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}
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out = append(out, blockData[:lastLen]...)
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} else {
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copy(blockData[:], data[(i-1)*blockSize:i*blockSize])
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// checksum ^= plaintext
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for j := 0; j < blockSize; j++ {
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checksum[j] ^= blockData[j]
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}
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// C = offset XOR E(offset XOR P)
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var tmp [16]byte
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for j := 0; j < blockSize; j++ {
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tmp[j] = offset[j] ^ blockData[j]
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}
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block.Encrypt(tmp[:], tmp[:])
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for j := 0; j < blockSize; j++ {
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tmp[j] ^= offset[j]
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}
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out = append(out, tmp[:]...)
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}
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} else {
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// Decrypt
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if i == m {
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lastLen := len(data) - tagLen - (i-1)*blockSize
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copy(blockData[:], data[(i-1)*blockSize:(i-1)*blockSize+lastLen])
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var pad [16]byte
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block.Encrypt(pad[:], offset[:])
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for j := 0; j < lastLen; j++ {
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blockData[j] ^= pad[j]
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}
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// Rebuild padded plaintext for checksum
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var padded [16]byte
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copy(padded[:], blockData[:lastLen])
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for j := lastLen; j < blockSize; j++ {
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padded[j] = pad[j]
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}
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for j := 0; j < blockSize; j++ {
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checksum[j] ^= padded[j]
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}
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out = append(out, blockData[:lastLen]...)
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} else {
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copy(blockData[:], data[(i-1)*blockSize:i*blockSize])
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// P = offset XOR D(offset XOR C)
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var tmp [16]byte
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for j := 0; j < blockSize; j++ {
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tmp[j] = offset[j] ^ blockData[j]
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}
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block.Decrypt(tmp[:], tmp[:])
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for j := 0; j < blockSize; j++ {
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tmp[j] ^= offset[j]
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}
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for j := 0; j < blockSize; j++ {
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checksum[j] ^= tmp[j]
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}
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out = append(out, tmp[:]...)
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}
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}
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}
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// --- Process associated data ---
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var adOffset [16]byte
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// adOffset = stretch[1..16]
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copy(adOffset[:], stretch[1:1+blockSize])
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var adSum [16]byte
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for len(ad) > 0 {
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// Update adOffset
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ntz := ntz(0)
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start := 1 + ntz
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for j := 0; j < blockSize; j++ {
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adOffset[j] ^= stretch[start+j]
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}
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var adBlock [16]byte
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if len(ad) >= blockSize {
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copy(adBlock[:], ad[:blockSize])
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ad = ad[blockSize:]
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} else {
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copy(adBlock[:], ad)
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adBlock[len(ad)] = 0x80 // 1 bit followed by zeros
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ad = nil
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}
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// adSum ^= E(adOffset XOR adBlock)
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for j := 0; j < blockSize; j++ {
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adBlock[j] ^= adOffset[j]
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}
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block.Encrypt(adBlock[:], adBlock[:])
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for j := 0; j < blockSize; j++ {
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adSum[j] ^= adBlock[j]
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}
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}
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// --- Compute tag ---
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// Final offset update for tag
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ntz := ntz(m)
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start := 1 + ntz
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for j := 0; j < blockSize; j++ {
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offset[j] ^= stretch[start+j]
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}
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// tag = E(offset XOR checksum) XOR adSum
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for j := 0; j < blockSize; j++ {
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offset[j] ^= checksum[j]
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}
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block.Encrypt(offset[:], offset[:])
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for j := 0; j < blockSize; j++ {
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offset[j] ^= adSum[j]
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}
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if encrypt {
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out = append(out, offset[:tagLen]...)
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} else {
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// Verify tag
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tag := data[len(data)-tagLen:]
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for j := 0; j < tagLen; j++ {
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if tag[j] != offset[j] {
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return nil, errors.New("gumble: OCB authentication failed")
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}
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}
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}
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return out, nil
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}
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// ntz returns the number of trailing zero bits in i.
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func ntz(i int) int {
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if i == 0 {
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return 0
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}
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n := 0
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for i&1 == 0 {
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i >>= 1
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n++
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}
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return n
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}
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// --- Mumble CryptSetup and UDP encryption support ---
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// cryptState holds the OCB encryption state for one direction of UDP audio.
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type cryptState struct {
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mu sync.Mutex
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key [16]byte
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nonce [12]byte // derived from IV
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encIV [16]byte // AES(key, IV)
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cipher cipher.Block
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counter uint32
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initialized bool
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}
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// cryptSetup sets up a cryptState from the CryptSetup message fields.
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func (cs *cryptState) setup(key, iv []byte) error {
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if len(key) != 16 {
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return errors.New("gumble: crypt key must be 16 bytes")
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}
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copy(cs.key[:], key)
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block, err := aes.NewCipher(cs.key[:])
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if err != nil {
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return err
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}
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cs.cipher = block
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// The Mumble nonce is derived from the IV:
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// nonce = AES_encrypt(key, iv)[0:4] || 0x0000000000000000
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// This is a 12-byte nonce (4 bytes encrypted IV + 8 zero bytes).
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var zeroIV [16]byte
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if len(iv) > 0 {
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copy(zeroIV[:], iv)
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}
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block.Encrypt(cs.encIV[:], zeroIV[:])
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copy(cs.nonce[:4], cs.encIV[:4])
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// bytes 4-11 remain zero
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cs.initialized = true
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return nil
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}
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// nonceForPacket returns the 12-byte OCB nonce for a given packet counter.
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// The counter is a 32-bit big-endian value.
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func (cs *cryptState) nonceForPacket(counter uint32) [12]byte {
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var n [12]byte
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copy(n[:], cs.nonce[:])
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// XOR the counter into the nonce at a fixed position.
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// Mumble uses: nonce = enc_iv[0:4] XOR counter_be
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binary.BigEndian.PutUint32(n[0:4], binary.BigEndian.Uint32(n[0:4])^counter)
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return n
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}
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// encrypt encrypts plaintext for UDP transmission. Returns ciphertext+tag.
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func (cs *cryptState) encrypt(counter uint32, plaintext []byte) ([]byte, error) {
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if !cs.initialized {
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return plaintext, nil // no encryption if not set up
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}
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nonce := cs.nonceForPacket(counter)
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return ocbEncrypt(cs.key[:], nonce[:], plaintext, nil)
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}
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// decrypt decrypts UDP ciphertext+tag. Returns plaintext.
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func (cs *cryptState) decrypt(counter uint32, ciphertext []byte) ([]byte, error) {
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if !cs.initialized {
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return ciphertext, nil
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}
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nonce := cs.nonceForPacket(counter)
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return ocbDecrypt(cs.key[:], nonce[:], ciphertext, nil)
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}
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// handleCryptSetup processes the CryptSetup message from the server.
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func (c *Client) handleCryptSetup(buffer []byte) error {
|
||||
var packet MumbleProto.CryptSetup
|
||||
if err := proto.Unmarshal(buffer, &packet); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
c.volatile.Lock()
|
||||
defer c.volatile.Unlock()
|
||||
|
||||
if packet.Key != nil && packet.ClientNonce != nil && packet.ServerNonce != nil {
|
||||
c.cryptOut.setup(packet.Key, packet.ClientNonce)
|
||||
c.cryptIn.setup(packet.Key, packet.ServerNonce)
|
||||
}
|
||||
|
||||
// Start UDP if we have a UDP connection and crypto is set up
|
||||
if c.cryptOut.initialized && c.udpConn != nil && !c.udpActive {
|
||||
c.udpActive = true
|
||||
go c.udpReadRoutine()
|
||||
go c.udpPingRoutine()
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
@@ -957,10 +957,6 @@ func (c *Client) handleQueryUsers(buffer []byte) error {
|
||||
return nil
|
||||
}
|
||||
|
||||
func (c *Client) handleCryptSetup(buffer []byte) error {
|
||||
return errUnimplementedHandler
|
||||
}
|
||||
|
||||
func (c *Client) handleContextActionModify(buffer []byte) error {
|
||||
var packet MumbleProto.ContextActionModify
|
||||
if err := proto.Unmarshal(buffer, &packet); err != nil {
|
||||
|
||||
@@ -0,0 +1,224 @@
|
||||
package gumble
|
||||
|
||||
import (
|
||||
"encoding/binary"
|
||||
"errors"
|
||||
"math"
|
||||
"net"
|
||||
"time"
|
||||
|
||||
"git.stormux.org/storm/barnard/gumble/gumble/varint"
|
||||
)
|
||||
|
||||
const (
|
||||
// udpPacketTypeOpus is the audio type byte for Opus over UDP.
|
||||
udpPacketTypeOpus = 4
|
||||
|
||||
// udpPingInterval is how often UDP ping packets are sent.
|
||||
udpPingInterval = 5 * time.Second
|
||||
|
||||
// maxUDPPacketSize is the maximum UDP packet size we'll process.
|
||||
maxUDPPacketSize = 1024
|
||||
)
|
||||
|
||||
// startUDP initializes a UDP connection to the server and begins reading
|
||||
// audio packets. It should be called after the server address is known.
|
||||
func (c *Client) startUDP() error {
|
||||
addr := c.Conn.RemoteAddr()
|
||||
udpAddr, err := net.ResolveUDPAddr("udp", addr.String())
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
conn, err := net.DialUDP("udp", nil, udpAddr)
|
||||
if err != nil {
|
||||
// UDP might not be available; fall back to TCP-only audio.
|
||||
// This is not an error — many Mumble servers work fine TCP-only.
|
||||
return nil
|
||||
}
|
||||
|
||||
c.udpConn = conn
|
||||
// The UDP reader and pinger will be started once CryptSetup is received.
|
||||
return nil
|
||||
}
|
||||
|
||||
// udpReadRoutine reads encrypted UDP audio packets from the server.
|
||||
func (c *Client) udpReadRoutine() {
|
||||
buf := make([]byte, maxUDPPacketSize)
|
||||
for {
|
||||
n, _, err := c.udpConn.ReadFromUDP(buf)
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
packet := make([]byte, n)
|
||||
copy(packet, buf[:n])
|
||||
c.handleUDPPacket(packet)
|
||||
}
|
||||
}
|
||||
|
||||
// udpPingRoutine sends periodic ping packets over UDP to keep the
|
||||
// connection alive and maintain NAT bindings.
|
||||
func (c *Client) udpPingRoutine() {
|
||||
ticker := time.NewTicker(udpPingInterval)
|
||||
defer ticker.Stop()
|
||||
|
||||
var counter uint32
|
||||
for {
|
||||
select {
|
||||
case <-c.end:
|
||||
return
|
||||
case <-ticker.C:
|
||||
c.sendUDPPing(counter)
|
||||
counter++
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// sendUDPPing sends a UDP ping packet. The Mumble UDP ping is a type
|
||||
// byte (0x20) followed by a varint-encoded timestamp.
|
||||
func (c *Client) sendUDPPing(counter uint32) {
|
||||
if c.udpConn == nil {
|
||||
return
|
||||
}
|
||||
// Type byte 0x20 (ping) + varint timestamp
|
||||
var ping [1 + varint.MaxVarintLen]byte
|
||||
ping[0] = 0x20
|
||||
n := varint.Encode(ping[1:], int64(time.Now().UnixNano()))
|
||||
c.udpConn.Write(ping[:1+n])
|
||||
}
|
||||
|
||||
// WriteAudioUDP writes an encrypted audio packet over UDP.
|
||||
// Returns true if the packet was sent over UDP, false if TCP should be used.
|
||||
func (c *Client) WriteAudioUDP(format, target byte, sequence int64, final bool, data []byte, X, Y, Z *float32) (bool, error) {
|
||||
if c.udpConn == nil || !c.cryptOut.initialized {
|
||||
return false, nil
|
||||
}
|
||||
|
||||
// Build the unencrypted header
|
||||
var header [1 + varint.MaxVarintLen*2]byte
|
||||
header[0] = (format << 5) | target
|
||||
n := varint.Encode(header[1:], int64(c.Self.Session))
|
||||
if n == 0 {
|
||||
return false, errors.New("gumble: varint out of range")
|
||||
}
|
||||
m := varint.Encode(header[1+n:], sequence)
|
||||
if m == 0 {
|
||||
return false, errors.New("gumble: varint out of range")
|
||||
}
|
||||
headerLen := 1 + n + m
|
||||
|
||||
// Build the unencrypted payload (length varint + opus data + positional)
|
||||
l := int64(len(data))
|
||||
if final {
|
||||
l |= 0x2000
|
||||
}
|
||||
var payload [varint.MaxVarintLen]byte
|
||||
p := varint.Encode(payload[:], l)
|
||||
if p == 0 {
|
||||
return false, errors.New("gumble: varint out of range")
|
||||
}
|
||||
|
||||
positionalLen := 0
|
||||
if X != nil {
|
||||
positionalLen = 3 * 4
|
||||
}
|
||||
|
||||
// Combine payload for encryption: length varint + opus data + positional
|
||||
plainPayload := make([]byte, p+len(data)+positionalLen)
|
||||
copy(plainPayload, payload[:p])
|
||||
copy(plainPayload[p:], data)
|
||||
if positionalLen > 0 {
|
||||
binary.LittleEndian.PutUint32(plainPayload[p+len(data):], math.Float32bits(*X))
|
||||
binary.LittleEndian.PutUint32(plainPayload[p+len(data)+4:], math.Float32bits(*Y))
|
||||
binary.LittleEndian.PutUint32(plainPayload[p+len(data)+8:], math.Float32bits(*Z))
|
||||
}
|
||||
|
||||
// Encrypt the payload
|
||||
c.cryptOut.mu.Lock()
|
||||
counter := c.cryptOut.counter
|
||||
c.cryptOut.counter++
|
||||
c.cryptOut.mu.Unlock()
|
||||
|
||||
encrypted, err := c.cryptOut.encrypt(counter, plainPayload)
|
||||
if err != nil {
|
||||
return false, err
|
||||
}
|
||||
|
||||
// Send: header (plain) + encrypted payload
|
||||
packet := make([]byte, headerLen+len(encrypted))
|
||||
copy(packet, header[:headerLen])
|
||||
copy(packet[headerLen:], encrypted)
|
||||
|
||||
_, err = c.udpConn.Write(packet)
|
||||
if err != nil {
|
||||
return false, err
|
||||
}
|
||||
return true, nil
|
||||
}
|
||||
|
||||
// handleUDPPacket processes an incoming UDP audio packet.
|
||||
func (c *Client) handleUDPPacket(packet []byte) {
|
||||
if len(packet) < 1 {
|
||||
return
|
||||
}
|
||||
|
||||
audioType := (packet[0] >> 5) & 0x7
|
||||
|
||||
// Skip ping packets
|
||||
if audioType != udpPacketTypeOpus {
|
||||
return
|
||||
}
|
||||
|
||||
// Find the user by session (in plaintext header)
|
||||
buf := packet[1:]
|
||||
session, n := varint.Decode(buf)
|
||||
if n <= 0 {
|
||||
return
|
||||
}
|
||||
buf = buf[n:]
|
||||
|
||||
// Parse sequence for decryption nonce
|
||||
seq, m := varint.Decode(buf)
|
||||
if m <= 0 {
|
||||
return
|
||||
}
|
||||
buf = buf[m:]
|
||||
|
||||
user := c.Users[uint32(session)]
|
||||
if user == nil {
|
||||
return
|
||||
}
|
||||
|
||||
// Decrypt the payload
|
||||
headerLen := 1 + n + m
|
||||
encrypted := packet[headerLen:]
|
||||
|
||||
if !c.cryptIn.initialized {
|
||||
return
|
||||
}
|
||||
|
||||
c.cryptIn.mu.Lock()
|
||||
counter := c.cryptIn.counter
|
||||
c.cryptIn.counter++
|
||||
c.cryptIn.mu.Unlock()
|
||||
|
||||
plaintext, err := c.cryptIn.decrypt(counter, encrypted)
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
|
||||
// Now feed the decrypted payload through the existing TCP audio handler.
|
||||
// We reconstruct the full UDPTunnel format: type byte + session + seq + payload.
|
||||
// The handleUDPTunnel expects: [type/target byte] [session varint] [seq varint] [length varint] [data] [pos]
|
||||
// Our decrypted payload is: [length varint] [data] [pos]
|
||||
// We need to prepend the type byte, session, and seq.
|
||||
fullPacket := make([]byte, 1+n+m+len(plaintext))
|
||||
fullPacket[0] = packet[0]
|
||||
varint.Encode(fullPacket[1:], session)
|
||||
varint.Encode(fullPacket[1+n:], seq)
|
||||
copy(fullPacket[1+n+m:], plaintext)
|
||||
|
||||
c.handleUDPTunnel(fullPacket)
|
||||
}
|
||||
|
||||
|
||||
Reference in New Issue
Block a user