Various progress I had forgotten to commit.

src/config.rs

@@ -212,8 +212,6 @@ impl Default for Config {
         Self {
             #[cfg(feature = "driver")]
             crypto_mode: CryptoMode::Aes256Gcm,
-            // crypto_mode: CryptoMode::XChaCha20Poly1305,
-            // crypto_mode: CryptoMode::Normal,
             #[cfg(all(feature = "driver", feature = "receive"))]
             decode_mode: DecodeMode::Decrypt,
             #[cfg(all(feature = "driver", feature = "receive"))]

src/driver/connection/mod.rs

@@ -105,8 +105,8 @@ impl Connection {
 
         let chosen_crypto = CryptoMode::negotiate(&ready.modes, Some(config.crypto_mode))?;
 
-        println!(
-            "wanted {:?}. chose {:?} from modes {:?}",
+        info!(
+            "Crypto scheme negotiation -- wanted {:?}. Chose {:?} from modes {:?}.",
             config.crypto_mode, chosen_crypto, ready.modes
         );
 
@@ -118,7 +118,7 @@ impl Connection {
         } else {
             let socket = Socket::from(udp.into_std()?);
 
-            // Some operating systems does not allow setting the recv buffer to 0.
+            // Some operating systems do not allow setting the recv buffer to 0.
             #[cfg(any(target_os = "linux", target_os = "windows"))]
             socket.set_recv_buffer_size(0)?;
 
@@ -162,10 +162,7 @@ impl Connection {
             let address_str = std::str::from_utf8(&view.get_address_raw()[..nul_byte_index])
                 .map_err(|_| Error::IllegalIp)?;
 
-            let address = IpAddr::from_str(address_str).map_err(|e| {
-                println!("{e:?}");
-                Error::IllegalIp
-            })?;
+            let address = IpAddr::from_str(address_str).map_err(|_| Error::IllegalIp)?;
 
             client
                 .send_json(&GatewayEvent::from(SelectProtocol {
@@ -183,7 +180,7 @@ impl Connection {
 
         info!("Connected to: {}", info.endpoint);
 
-        info!("WS heartbeat duration {}ms.", hello.heartbeat_interval,);
+        info!("WS heartbeat duration {}ms.", hello.heartbeat_interval);
 
         let (ws_msg_tx, ws_msg_rx) = flume::unbounded();
         #[cfg(feature = "receive")]

src/driver/crypto.rs

@@ -63,30 +63,9 @@ impl NuCipher {
     ) -> Result<(), CryptoError> {
         let header_len = packet.packet().len() - packet.payload().len();
 
-        println!(
-            "Think I have payl_len {payload_len}, pkt {} non-hdr {} (hdr {header_len}). splits pre {} post {}",
-            packet.packet().len(),
-            packet.payload().len(),
-            mode.payload_prefix_len2(),
-            mode.payload_suffix_len(),
-        );
-
         let (header, body) = packet.packet_mut().split_at_mut(header_len);
         let (slice_to_use, body_remaining) = mode.nonce_slice(header, &mut body[..payload_len])?;
 
-        println!(
-            "Question time. nonce_slice {:0x?} (l{}) body {:0x?} (l{})",
-            slice_to_use,
-            slice_to_use.len(),
-            body_remaining,
-            body_remaining.len(),
-        );
-
-        println!(
-            "think I'm reading nonce from {:?} (sz4)",
-            slice_to_use.as_ptr()
-        );
-
         // body_remaining is now correctly truncated to exclude the nonce by this point.
         // the true_payload to encrypt is within the buf[prefix:-suffix].
         let (pre_payload, body_remaining) = body_remaining.split_at_mut(mode.payload_prefix_len2());
@@ -95,31 +74,31 @@ impl NuCipher {
 
         // All these Nonce types are distinct at the type level
         // (96b for AES, 192b for XSalsa/XChaCha).
-        // TODO: E2EE apparently wants the least significant bytes used.
-        //       This scheme uses most significant bytes.
         match self {
+            // Older modes place the tag before the payload and do not authenticate
+            // cleartext.
             NuCipher::XSalsa20Poly1305(secret_box) => {
                 let mut nonce = SbNonce::default();
                 nonce[..mode.nonce_size()].copy_from_slice(slice_to_use);
 
                 let tag = secret_box.encrypt_in_place_detached(&nonce, b"", body)?;
                 pre_payload[..TAG_SIZE].copy_from_slice(&tag[..]);
             },
+
+            // The below variants follow part of the SRTP spec (RFC3711, sec 3.1)
+            // by requiring that we include the cleartext header portion as
+            // authenticated data. Discord themselves do not mention this requirement.
             NuCipher::Aes256Gcm(aes_gcm) => {
                 let mut nonce = AesNonce::default();
                 nonce[..mode.nonce_size()].copy_from_slice(slice_to_use);
-                // let l = nonce.len();
-                // nonce[l-mode.nonce_size()..].copy_from_slice(slice_to_use);
 
-                // let tag = aes_gcm.encrypt_in_place_detached(&nonce, b"", body)?;
                 let tag = aes_gcm.encrypt_in_place_detached(&nonce, header, body)?;
                 post_payload[..TAG_SIZE].copy_from_slice(&tag[..]);
             },
             NuCipher::XChaCha20Poly1305(cha_cha_poly1305) => {
                 let mut nonce = XNonce::default();
                 nonce[..mode.nonce_size()].copy_from_slice(slice_to_use);
 
-                // let tag = cha_cha_poly1305.encrypt_in_place_detached(&nonce, b"", body)?;
                 let tag = cha_cha_poly1305.encrypt_in_place_detached(&nonce, header, body)?;
                 post_payload[..TAG_SIZE].copy_from_slice(&tag[..]);
             },
@@ -140,7 +119,8 @@ pub enum CryptoMode {
     /// An additional random 4B suffix is used as the source of nonce bytes for the packet.
     /// This nonce value increments by `1` with each packet.
     ///
-    /// Encrypted content begins *after* the RTP header, following the SRTP specification.
+    /// Encrypted content begins *after* the RTP header and extensions, following the SRTP
+    /// specification.
     ///
     /// Nonce width of 4B (32b), at an extra 4B per packet (~0.2 kB/s).
     Aes256Gcm,
@@ -150,7 +130,8 @@ pub enum CryptoMode {
     /// An additional random 4B suffix is used as the source of nonce bytes for the packet.
     /// This nonce value increments by `1` with each packet.
     ///
-    /// Encrypted content begins *after* the RTP header, following the SRTP specification.
+    /// Encrypted content begins *after* the RTP header and extensions, following the SRTP
+    /// specification.
     ///
     /// Nonce width of 4B (32b), at an extra 4B per packet (~0.2 kB/s).
     XChaCha20Poly1305,
@@ -558,11 +539,11 @@ impl CryptoState {
             Self::Lite(ref mut i)
             | Self::Aes256Gcm(ref mut i)
             | Self::XChaCha20Poly1305(ref mut i) => {
-                let mut mslice = &mut packet.payload_mut()[startpoint..endpoint];
-                println!("think I'm writing nonce to {:?} (sz4)", mslice.as_ptr());
-                mslice.write_u32::<NetworkEndian>(i.0).expect(
-                    "Nonce size is guaranteed to be sufficient to write u32 for lite tagging.",
-                );
+                (&mut packet.payload_mut()[startpoint..endpoint])
+                    .write_u32::<NetworkEndian>(i.0)
+                    .expect(
+                        "Nonce size is guaranteed to be sufficient to write u32 for lite tagging.",
+                    );
                 *i += Wrapping(1);
             },
             Self::Normal => {},

src/driver/tasks/mixer/mod.rs

@@ -529,8 +529,6 @@ impl Mixer {
             out
         };
 
-        println!("mixed: {mix_len:?}");
-
         if self.muted {
             mix_len = MixType::MixedPcm(0);
         }
@@ -690,8 +688,6 @@ impl Mixer {
             .as_ref()
             .expect("Shouldn't be mixing packets without access to a cipher + UDP dest.");
 
-        println!("sent pkt (l{}) {:0x?}", packet.len(), packet);
-
         #[cfg(test)]
         if let Some(OutputMode::Rtp(tx)) = &self.config.override_connection {
             // Test mode: send unencrypted (compressed) packets to local receiver.

src/input/adapters/async_adapter.rs

@@ -254,7 +254,6 @@ impl Read for AsyncAdapterStream {
                     self.check_dropped()?;
                 },
                 a => {
-                    println!("Misc err {a:?}");
                     return a;
                 },
             }