Added a unit test to check the SDP media format order. Tightened up the SDP owner parsing. (sipsorcery-org#1248)

Author: sipsorcery

src/net/SDP/SDP.cs

@@ -1,4 +1,4 @@
-//-----------------------------------------------------------------------------
+//-----------------------------------------------------------------------------
 // Filename: SDP.cs
 //
 // Description: Session Description Protocol implementation as defined in RFC 2327.
@@ -234,13 +234,21 @@ public static SDP ParseSDPDescription(string sdpDescription)
                                 break;
 
                             case var l when l.StartsWith("o="):
-                                string[] ownerFields = sdpLineTrimmed.Substring(2).Split(' ');
-                                sdp.Username = ownerFields[0];
-                                sdp.SessionId = ownerFields[1];
-                                UInt64.TryParse(ownerFields[2], out sdp.AnnouncementVersion);
-                                sdp.NetworkType = ownerFields[3];
-                                sdp.AddressType = ownerFields[4];
-                                sdp.AddressOrHost = ownerFields[5];
+                                var ownerFields = sdpLineTrimmed.Substring(2).Split(new []{' '}, 6, StringSplitOptions.RemoveEmptyEntries);
+
+                                if (ownerFields.Length >= 5)
+                                {
+                                    sdp.Username = ownerFields[0];
+                                    sdp.SessionId = ownerFields[1];
+                                    sdp.AnnouncementVersion = UInt64.TryParse(ownerFields[2], out var version) ? version : 0;
+                                    sdp.NetworkType = ownerFields[3];
+                                    sdp.AddressType = ownerFields[4];
+                                    sdp.AddressOrHost = ownerFields.ElementAtOrDefault(5); // Safely handle missing elements
+                                }
+                                else
+                                {
+                                   logger.LogWarning($"The SDP message had an invalid SDP line format for 'o=': {sdpLineTrimmed}");
+                                }
                                 break;
 
                             case var l when l.StartsWith("s="):
@@ -779,7 +787,7 @@ public static SDP ParseSDPDescription(string sdpDescription)
             }
             catch (Exception excp)
             {
-                logger.LogError("Exception ParseSDPDescription. " + excp.Message);
+                logger.LogError("Exception ParseSDPDescription. " + excp);
                 throw;
             }
         }

test/unit/net/SDP/SDPUnitTests.cs

@@ -9,6 +9,7 @@
 // BSD 3-Clause "New" or "Revised" License, see included LICENSE.md file.
 //-----------------------------------------------------------------------------
 
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Net;
@@ -1280,5 +1281,34 @@ public void AnnoucementMediaCheckTest()
             Assert.Equal("text/plain", sdp.Media.First().MessageMediaFormat.AcceptTypes[0]);
             Assert.Equal("text/x-msrp-heartbeat", sdp.Media.First().MessageMediaFormat.AcceptTypes[1]);
         }
+
+        /// <summary>
+        /// The media format negotiation rules specify that the first common format in the offer and answer
+        /// should be chiosen. This test checks that the media formats are maintained in the order they were added.
+        /// </summary>
+        [Fact]
+        public void Media_Formats_Order_Test()
+        {
+            logger.LogDebug("--> " + System.Reflection.MethodBase.GetCurrentMethod().Name);
+
+            var sdp = new SDP();
+
+            sdp.Media.Add(new SDPMediaAnnouncement()
+            {
+                Media = SDPMediaTypesEnum.audio,
+                MediaFormats = new Dictionary<int, SDPAudioVideoMediaFormat>
+                {
+                    { 8, new SDPAudioVideoMediaFormat(SDPMediaTypesEnum.audio, 8, "PCMA", 8000) },
+                    { 0, new SDPAudioVideoMediaFormat(SDPMediaTypesEnum.audio, 0, "PCMU", 8000) },
+                    { 101, new SDPAudioVideoMediaFormat(SDPMediaTypesEnum.audio, 101, "telephone-event", 8000) }
+                }
+            });
+
+            logger.LogDebug(sdp.ToString());
+
+            var sdpParsed = SDP.ParseSDPDescription(sdp.ToString());
+
+            Assert.Equal(8, sdpParsed.Media.Where(x => x.Media == SDPMediaTypesEnum.audio).First().MediaFormats.First().Key);
+        }
     }
 }