ptmap: implicitly match '/8000' and '/8000/1'

In codecs_same(), do not compare the complete audio_name. The parts of it are
already checked individually:
- subtype_name ("AMR"),
- rate ("8000"; defaults to 8000 if omitted) and
- channels ("1"; defaults to 1 if omitted)
So by also checking the complete audio_name, we brushed over the match of
implicit "/8000" and "/8000/1", which otherwise works out fine.

As a result, translating payload type numbers in RTP headers now also works if
one conn of an endpoint set an rtpmap with "AMR/8000" and the other conn set
"AMR/8000/1".

It seems to me that most PBX out there generate ptmaps omitting the "/1", so
fixing this should make us more interoperable with third party SDP.

See IETF RFC4566 section 6. SDP Attributes:
  For audio streams, <encoding parameters> indicates the number
  of audio channels.  This parameter is OPTIONAL and may be
  omitted if the number of channels is one, provided that no
  additional parameters are needed.

Also allowing to omit the "/8000" is a mere side effect of this patch.
Omitting the rate does not seem to be specified in an RFC, but is logical for
audio codecs defined to require exactly 8000 set as rate (most GSM codecs).

Add tests in mgcp_test.c.

Change-Id: Iab00bf9a55b1847f85999077114b37e70fb677c2

src/libosmo-mgcp/mgcp_codec.c

@@ -379,8 +379,6 @@ static bool codecs_same(struct mgcp_rtp_codec *codec_a, struct mgcp_rtp_codec *c
 		return false;
 	if (codec_a->frame_duration_den != codec_b->frame_duration_den)
 		return false;
-	if (strcmp(codec_a->audio_name, codec_b->audio_name))
-		return false;
 	if (strcmp(codec_a->subtype_name, codec_b->subtype_name))
 		return false;
 	if (!strcmp(codec_a->subtype_name, "AMR")) {

tests/mgcp/mgcp_test.c

@@ -1900,6 +1900,70 @@ static const struct testcase_mgcp_codec_pt_translate test_mgcp_codec_pt_translat
 			{ .end = true },
 		},
 	},
+	{
+		.descr = "match FOO/8000/1 and FOO/8000 as identical, single channel is implicit",
+		.codecs = {
+			{
+				{ 0, "PCMU/8000/1", NULL, },
+				{ 111, "GSM-HR-08/8000/1", NULL, },
+				{ 112, "AMR/8000/1", &amr_param_octet_aligned_true, },
+			},
+			{
+				{ 97, "GSM-HR-08/8000", NULL, },
+				{ 0, "PCMU/8000", NULL, },
+				{ 96, "AMR/8000", &amr_param_octet_aligned_true, },
+			},
+		},
+		.expect = {
+			{ .payload_type_map = {112, 96}, },
+			{ .payload_type_map = {0, 0}, },
+			{ .payload_type_map = {111, 97} },
+			{ .payload_type_map = {123, -EINVAL} },
+			{ .end = true },
+		},
+	},
+	{
+		.descr = "match FOO/8000/1 and FOO as identical, 8k and single channel are implicit",
+		.codecs = {
+			{
+				{ 0, "PCMU/8000/1", NULL, },
+				{ 111, "GSM-HR-08/8000/1", NULL, },
+				{ 112, "AMR/8000/1", &amr_param_octet_aligned_true, },
+			},
+			{
+				{ 97, "GSM-HR-08", NULL, },
+				{ 0, "PCMU", NULL, },
+				{ 96, "AMR", &amr_param_octet_aligned_true, },
+			},
+		},
+		.expect = {
+			{ .payload_type_map = {112, 96}, },
+			{ .payload_type_map = {0, 0}, },
+			{ .payload_type_map = {111, 97} },
+			{ .payload_type_map = {123, -EINVAL} },
+			{ .end = true },
+		},
+	},
+	{
+		.descr = "test whether channel number matching is waterproof",
+		.codecs = {
+			{
+				{ 111, "GSM-HR-08/8000", },
+				{ 112, "GSM-HR-08/8000/2", .expect_rc = -22},
+				{ 113, "GSM-HR-08/8000/3", .expect_rc = -22},
+			},
+			{
+				{ 122, "GSM-HR-08/8000/2", .expect_rc = -22},
+				{ 121, "GSM-HR-08/8000/1", },
+			},
+		},
+		.expect = {
+			{ .payload_type_map = {111, 121}, },
+			{ .payload_type_map = {112, -EINVAL} },
+			{ .payload_type_map = {113, -EINVAL} },
+			{ .end = true },
+		},
+	},
 };
 
 static void test_mgcp_codec_pt_translate(void)

tests/mgcp/mgcp_test.ok

@@ -1315,6 +1315,50 @@ Testing mgcp_codec_pt_translate()
  - mgcp_codec_pt_translate(conn0, conn1, 111) -> -22
  - mgcp_codec_pt_translate(conn0, conn1, 112) -> 122
  - mgcp_codec_pt_translate(conn1, conn0, 122) -> 112
+#8: match FOO/8000/1 and FOO/8000 as identical, single channel is implicit
+ - add codecs on conn0:
+    0:   0 PCMU/8000/1  -> rc=0
+    1: 111 GSM-HR-08/8000/1  -> rc=0
+    2: 112 AMR/8000/1 octet-aligned=1  -> rc=0
+ - add codecs on conn1:
+    0:  97 GSM-HR-08/8000  -> rc=0
+    1:   0 PCMU/8000  -> rc=0
+    2:  96 AMR/8000 octet-aligned=1  -> rc=0
+ - mgcp_codec_pt_translate(conn0, conn1, 112) -> 96
+ - mgcp_codec_pt_translate(conn1, conn0, 96) -> 112
+ - mgcp_codec_pt_translate(conn0, conn1, 0) -> 0
+ - mgcp_codec_pt_translate(conn1, conn0, 0) -> 0
+ - mgcp_codec_pt_translate(conn0, conn1, 111) -> 97
+ - mgcp_codec_pt_translate(conn1, conn0, 97) -> 111
+ - mgcp_codec_pt_translate(conn0, conn1, 123) -> -22
+#9: match FOO/8000/1 and FOO as identical, 8k and single channel are implicit
+ - add codecs on conn0:
+    0:   0 PCMU/8000/1  -> rc=0
+    1: 111 GSM-HR-08/8000/1  -> rc=0
+    2: 112 AMR/8000/1 octet-aligned=1  -> rc=0
+ - add codecs on conn1:
+    0:  97 GSM-HR-08  -> rc=0
+    1:   0 PCMU  -> rc=0
+    2:  96 AMR octet-aligned=1  -> rc=0
+ - mgcp_codec_pt_translate(conn0, conn1, 112) -> 96
+ - mgcp_codec_pt_translate(conn1, conn0, 96) -> 112
+ - mgcp_codec_pt_translate(conn0, conn1, 0) -> 0
+ - mgcp_codec_pt_translate(conn1, conn0, 0) -> 0
+ - mgcp_codec_pt_translate(conn0, conn1, 111) -> 97
+ - mgcp_codec_pt_translate(conn1, conn0, 97) -> 111
+ - mgcp_codec_pt_translate(conn0, conn1, 123) -> -22
+#10: test whether channel number matching is waterproof
+ - add codecs on conn0:
+    0: 111 GSM-HR-08/8000  -> rc=0
+    1: 112 GSM-HR-08/8000/2  -> rc=-22
+    2: 113 GSM-HR-08/8000/3  -> rc=-22
+ - add codecs on conn1:
+    0: 122 GSM-HR-08/8000/2  -> rc=-22
+    1: 121 GSM-HR-08/8000/1  -> rc=0
+ - mgcp_codec_pt_translate(conn0, conn1, 111) -> 121
+ - mgcp_codec_pt_translate(conn1, conn0, 121) -> 111
+ - mgcp_codec_pt_translate(conn0, conn1, 112) -> -22
+ - mgcp_codec_pt_translate(conn0, conn1, 113) -> -22
 
 Testing test_conn_id_matching
 needle='23AB' found '000023AB'