make default RAN codecs configurable in ran_infra

Instead of generating the default codecs list for a RAN for each call,
place a pre-composed list in ran_infra.c.

(1) The main aim is to allow configuring this list -- subsequent commit
Ib5655214ce48c66d095e8f1b7b7106ac3ee43ec0 will add the VTY commands to
modify the predefined lists.

(2) As a free side effect, this also allows configuring the order of
preference for specific codecs.

(3) It may also save us some iterations of the codec_map[], which may
grow a lot more variants; for example, we could add one entry for each
possible AMR mode-set...

Change-Id: If46231a53f7512dbd81790fd30462d65fe059aa3

include/osmocom/msc/codec_filter.h

@@ -44,7 +44,7 @@ struct codec_filter {
 	struct sdp_audio_codec assignment;
 };
 
-void codec_filter_set_ran(struct codec_filter *codec_filter, enum osmo_rat_type ran_type);
+void codec_filter_set_ran(struct codec_filter *codec_filter, const struct sdp_audio_codecs *codecs);
 void codec_filter_set_bss(struct codec_filter *codec_filter,
 			  const struct gsm0808_speech_codec_list *codec_list_bss_supported);
 int codec_filter_run(struct codec_filter *codec_filter, struct sdp_msg *result, const struct sdp_msg *remote);

include/osmocom/msc/ran_infra.h

@@ -26,6 +26,9 @@ struct ran_infra {
 	const ran_dec_l2_t ran_dec_l2;
 	const ran_encode_t ran_encode;
 	struct sccp_ran_inst *sri;
+	/* Codecs available on this RAN type by default, in order of preference. If empty, all known codecs will be
+	 * allowed and offered to peers. */
+	struct sdp_audio_codecs codecs;
 	/* To always set up the MGW endpoint facing the RAN side with specific codecs, list those here. Otherwise leave
 	 * empty (to use the result of codecs filtering). This exists for IuCS, to always set the MGW endpoint facing
 	 * RAN to IUFP, to decapsulate the IuUP headers. */

src/libmsc/codec_filter.c

@@ -25,52 +25,16 @@
 
 #include <osmocom/msc/codec_filter.h>
 #include <osmocom/msc/codec_mapping.h>
+#include <osmocom/msc/ran_infra.h>
 #include <osmocom/msc/debug.h>
 
-/* Add all known payload types encountered in GSM networks */
-static void sdp_add_all_geran_codecs(struct sdp_audio_codecs *ac)
-{
-	/* In order of preference. TODO: make configurable */
-	static const enum gsm48_bcap_speech_ver mobile_codecs[] = {
-		GSM48_BCAP_SV_AMR_F	/*!< 4   GSM FR V3 (FR AMR) */,
-		GSM48_BCAP_SV_AMR_H	/*!< 5   GSM HR V3 (HR_AMR) */,
-		GSM48_BCAP_SV_EFR	/*!< 2   GSM FR V2 (GSM EFR) */,
-		GSM48_BCAP_SV_FR	/*!< 0   GSM FR V1 (GSM FR) */,
-		GSM48_BCAP_SV_HR	/*!< 1   GSM HR V1 (GSM HR) */,
-	};
-	int i;
-	for (i = 0; i < ARRAY_SIZE(mobile_codecs); i++)
-		sdp_audio_codecs_add_speech_ver(ac, mobile_codecs[i]);
-}
-
-/* Add all known AMR payload types encountered in UTRAN networks */
-static void sdp_add_all_utran_codecs(struct sdp_audio_codecs *ac)
-{
-	/* In order of preference. TODO: make configurable */
-	static const enum gsm48_bcap_speech_ver utran_codecs[] = {
-		GSM48_BCAP_SV_AMR_F	/*!< 4   GSM FR V3 (FR AMR) */,
-		GSM48_BCAP_SV_AMR_H	/*!< 5   GSM HR V3 (HR_AMR) */,
-		GSM48_BCAP_SV_AMR_FW	/*!< 8   GSM FR V5 (FR AMR-WB) */,
-	};
-	int i;
-	for (i = 0; i < ARRAY_SIZE(utran_codecs); i++)
-		sdp_audio_codecs_add_speech_ver(ac, utran_codecs[i]);
-}
-
-void codec_filter_set_ran(struct codec_filter *codec_filter, enum osmo_rat_type ran_type)
+void codec_filter_set_ran(struct codec_filter *codec_filter, const struct sdp_audio_codecs *codecs)
 {
+	const struct sdp_audio_codec *c;
 	codec_filter->ran = (struct sdp_audio_codecs){};
-
-	switch (ran_type) {
-	default:
-	case OSMO_RAT_GERAN_A:
-		sdp_add_all_geran_codecs(&codec_filter->ran);
-		break;
-
-	case OSMO_RAT_UTRAN_IU:
-		sdp_add_all_utran_codecs(&codec_filter->ran);
-		break;
-	}
+	/* Add codecs one by one, to resolve any payload type number conflicts or duplicates. */
+	sdp_audio_codecs_foreach (c, codecs)
+		sdp_audio_codecs_add_copy(&codec_filter->ran, c, true, true);
 }
 
 void codec_filter_set_bss(struct codec_filter *codec_filter,

src/libmsc/ran_infra.c

@@ -28,6 +28,7 @@
 #include <osmocom/msc/ran_msg_a.h>
 #include <osmocom/msc/ran_msg_iu.h>
 #include <osmocom/msc/ran_peer.h>
+#include <osmocom/msc/codec_mapping.h>
 
 #include <osmocom/msc/ran_infra.h>
 
@@ -128,3 +129,31 @@ struct ran_infra msc_ran_infra[] = {
 };
 
 const int msc_ran_infra_len = ARRAY_SIZE(msc_ran_infra);
+
+static __attribute__((constructor)) void on_dso_load_geran(void)
+{
+	/* Initialize GERAN default codecs, in order of preference. By definition, all codec_mapping entries that match
+	 * one of the GERAN GMSK Speech Versions are available. */
+	static const enum gsm48_bcap_speech_ver mobile_codecs[] = {
+		GSM48_BCAP_SV_AMR_F	/*!< 4   GSM FR V3 (FR AMR) */,
+		GSM48_BCAP_SV_AMR_H	/*!< 5   GSM HR V3 (HR_AMR) */,
+		GSM48_BCAP_SV_EFR	/*!< 2   GSM FR V2 (GSM EFR) */,
+		GSM48_BCAP_SV_FR	/*!< 0   GSM FR V1 (GSM FR) */,
+		GSM48_BCAP_SV_HR	/*!< 1   GSM HR V1 (GSM HR) */,
+	};
+	int i;
+	for (i = 0; i < ARRAY_SIZE(mobile_codecs); i++)
+		sdp_audio_codecs_add_speech_ver(&msc_ran_infra[OSMO_RAT_GERAN_A].codecs, mobile_codecs[i]);
+}
+
+static __attribute__((constructor)) void on_dso_load_utran(void)
+{
+	static const enum gsm48_bcap_speech_ver utran_codecs[] = {
+		GSM48_BCAP_SV_AMR_F	/*!< 4   GSM FR V3 (FR AMR) */,
+		GSM48_BCAP_SV_AMR_H	/*!< 5   GSM HR V3 (HR_AMR) */,
+		GSM48_BCAP_SV_AMR_FW	/*!< 8   GSM FR V5 (FR AMR-WB) */,
+	};
+	int i;
+	for (i = 0; i < ARRAY_SIZE(utran_codecs); i++)
+		sdp_audio_codecs_add_speech_ver(&msc_ran_infra[OSMO_RAT_UTRAN_IU].codecs, utran_codecs[i]);
+}

src/libmsc/transaction_cc.c

@@ -25,6 +25,7 @@
 #include <osmocom/msc/transaction_cc.h>
 #include <osmocom/msc/codec_filter.h>
 #include <osmocom/msc/csd_filter.h>
+#include <osmocom/msc/ran_infra.h>
 
 void trans_cc_filter_init(struct gsm_trans *trans)
 {
@@ -34,7 +35,7 @@ void trans_cc_filter_init(struct gsm_trans *trans)
 
 void trans_cc_filter_set_ran(struct gsm_trans *trans, enum osmo_rat_type ran_type)
 {
-	codec_filter_set_ran(&trans->cc.codecs, ran_type);
+	codec_filter_set_ran(&trans->cc.codecs, &msc_ran_infra[ran_type].codecs);
 	csd_filter_set_ran(&trans->cc.csd, ran_type);
 }