Bug 1491511: add Telemetry for SRTP cipher usage. r=mt

Bug 1491511: add Telemetry for SRTP cipher usage. r=mt

Differential Revision: https://phabricator.services.mozilla.com/D5956

--HG--
extra : moz-landing-system : lando

media/mtransport/transportlayerdtls.cpp

@@ -1528,7 +1528,7 @@ TransportLayerDtls::RecordCipherTelemetry() {
   nsresult rv = GetCipherSuite(&cipher);
 
   if (NS_FAILED(rv)) {
-    MOZ_MTLOG(ML_ERROR, "Failed to get cipher suite");
+    MOZ_MTLOG(ML_ERROR, "Failed to get DTLS cipher suite");
     return;
   }
 
@@ -1580,6 +1580,34 @@ TransportLayerDtls::RecordCipherTelemetry() {
   }
 
   Telemetry::Accumulate(Telemetry::WEBRTC_DTLS_CIPHER, t_cipher);
+
+  rv = GetSrtpCipher(&cipher);
+
+  if (NS_FAILED(rv)) {
+    MOZ_MTLOG(ML_ERROR, "Failed to get SRTP cipher suite");
+    return;
+  }
+
+  mozilla::Telemetry::LABELS_WEBRTC_SRTP_CIPHER label =
+    mozilla::Telemetry::LABELS_WEBRTC_SRTP_CIPHER::Unknown;
+
+  switch (cipher) {
+    case kDtlsSrtpAes128CmHmacSha1_80:
+      label = Telemetry::LABELS_WEBRTC_SRTP_CIPHER::Aes128CmHmacSha1_80;
+      break;
+    case kDtlsSrtpAes128CmHmacSha1_32:
+      label = Telemetry::LABELS_WEBRTC_SRTP_CIPHER::Aes128CmHmacSha1_32;
+      break;
+    case kDtlsSrtpAeadAes128Gcm:
+      label = Telemetry::LABELS_WEBRTC_SRTP_CIPHER::AeadAes128Gcm;
+      break;
+    case kDtlsSrtpAeadAes256Gcm:
+      label = Telemetry::LABELS_WEBRTC_SRTP_CIPHER::AeadAes256Gcm;
+      break;
+  }
+
+  Telemetry::AccumulateCategorical(label);
+
 }
 
 }  // close namespace

toolkit/components/telemetry/Histograms.json

@@ -8673,6 +8673,15 @@
     "n_values": 14,
     "description": "The DTLS cipher (as integer) negotiated for a RTCPeerConnection. See TransportLayerDtls::RecordCipherTelemetry for the meaning of the values"
   },
+  "WEBRTC_SRTP_CIPHER": {
+    "record_in_processes": ["content"],
+    "alert_emails": ["webrtc-dtls-telemetry-alerts@mozilla.com", "nohlmeier@mozilla.com"],
+    "bug_numbers": [1491511],
+    "expires_in_version": "67",
+    "kind": "categorical",
+    "labels": ["Unknown", "Aes128CmHmacSha1_80", "Aes128CmHmacSha1_32", "AeadAes128Gcm", "AeadAes256Gcm"],
+    "description": "The SRTP cipher (as integer) negotiated for a RTCPeerConnection. See TransportLayerDtls::RecordCipherTelemetry for the meaning of the values"
+  },
   "WEBRTC_ICE_FINAL_CONNECTION_STATE": {
     "record_in_processes": ["main", "content"],
     "alert_emails": ["webrtc-ice-telemetry-alerts@mozilla.com, nohlmeier@mozilla.com"],