Log call session description.

Signal/src/call/CallService.swift

@@ -407,6 +407,8 @@ private class SignalCallData: NSObject {
                 throw CallError.obsoleteCall(description: "Missing peerConnectionClient")
             }
 
+            Logger.info("session description for outgoing call: \(call.identifiersForLogs), sdp: \(sessionDescription.logSafeDescription).")
+
             return peerConnectionClient.setLocalSessionDescription(sessionDescription).then {
                 do {
                     let offerBuilder = SSKProtoCallMessageOffer.SSKProtoCallMessageOfferBuilder(id: call.signalingId,
@@ -708,12 +710,12 @@ private class SignalCallData: NSObject {
             // Find a sessionDescription compatible with my constraints and the remote sessionDescription
             return peerConnectionClient.negotiateSessionDescription(remoteDescription: offerSessionDescription, constraints: constraints)
         }.then { (negotiatedSessionDescription: HardenedRTCSessionDescription) in
-            Logger.debug("set the remote description for: \(newCall.identifiersForLogs)")
-
             guard self.call == newCall else {
                 throw CallError.obsoleteCall(description: "negotiateSessionDescription() response for obsolete call")
             }
 
+            Logger.info("session description for incoming call: \(newCall.identifiersForLogs), sdp: \(negotiatedSessionDescription.logSafeDescription).")
+
             do {
                 let answerBuilder = SSKProtoCallMessageAnswer.SSKProtoCallMessageAnswerBuilder(id: newCall.signalingId,
                                                                                                sessionDescription: negotiatedSessionDescription.sdp)

Signal/src/call/PeerConnectionClient.swift

@@ -1109,6 +1109,17 @@ class HardenedRTCSessionDescription {
 
         return RTCSessionDescription.init(type: rtcSessionDescription.type, sdp: description)
     }
+
+    var logSafeDescription: String {
+        do {
+            let pattern = "\\d+\\.\\d+\\.\\d+\\.\\d+"
+            let regex = try NSRegularExpression(pattern: pattern, options: NSRegularExpression.Options.caseInsensitive)
+            let range = NSRange(location: 0, length: sdp.count)
+            return regex.stringByReplacingMatches(in: sdp, options: [], range: range, withTemplate: "<ip address>")
+        } catch {
+            return "<Could not filter session description>"
+        }
+    }
 }
 
 protocol VideoCaptureSettingsDelegate: class {