[bssap] Attempt to allow selecting the speech mode from config

It is possible to specify a list of possible speech codecs
and we will try to match the assignment command with the
one from the config file. This is not tested yet and we have
one problem. We assume we can modify the channel to hold
the speech value... this will require more work.

1 files changed, 86 insertions, 14 deletions

diff --git a/openbsc/src/bssap.c b/openbsc/src/bssap.c
index 26ab998fa..8941bab21 100644
--- a/openbsc/src/bssap.c
+++ b/openbsc/src/bssap.c
@@ -32,6 +32,7 @@
 #include <sccp/sccp.h>
 
 #include <arpa/inet.h>
+#include <assert.h>
 
 
 #define BSSMAP_MSG_SIZE 512
@@ -283,6 +284,64 @@ static void bssmap_t10_fired(void *_conn)
 }
 
 /*
+ * helpers for the assignment command
+ */
+enum gsm0808_permitted_speech audio_support_to_gsm88(struct gsm_audio_support *audio)
+{
+	if (audio->hr) {
+		switch (audio->ver) {
+		case 1:
+			return GSM0808_PERM_HR1;
+			break;
+		case 2:
+			return GSM0808_PERM_HR2;
+			break;
+		case 3:
+			return GSM0808_PERM_HR3;
+			break;
+		default:
+			    DEBUGP(DMSC, "Wrong speech mode: %d\n", audio->ver);
+			    return GSM0808_PERM_FR1;
+		}
+	} else {
+		switch (audio->ver) {
+		case 1:
+			return GSM0808_PERM_FR1;
+			break;
+		case 2:
+			return GSM0808_PERM_FR2;
+			break;
+		case 3:
+			return GSM0808_PERM_FR3;
+			break;
+		default:
+			    DEBUGP(DMSC, "Wrong speech mode: %d\n", audio->ver);
+			    return GSM0808_PERM_HR1;
+		}
+	}
+}
+
+enum gsm48_chan_mode gsm88_to_chan_mode(enum gsm0808_permitted_speech speech)
+{
+	switch (speech) {
+	case GSM0808_PERM_HR1:
+	case GSM0808_PERM_FR1:
+		return GSM48_CMODE_SPEECH_V1;
+		break;
+	case GSM0808_PERM_HR2:
+	case GSM0808_PERM_FR2:
+		return GSM48_CMODE_SPEECH_EFR;
+		break;
+	case GSM0808_PERM_HR3:
+	case GSM0808_PERM_FR3:
+		return GSM48_CMODE_SPEECH_AMR;
+		break;
+	}
+
+	assert(0);
+}
+
+/*
  * Handle the assignment request message.
  *
  * See §3.2.1.1 for the message type
@@ -290,11 +349,13 @@ static void bssmap_t10_fired(void *_conn)
 static int bssmap_handle_assignm_req(struct sccp_connection *conn,
 				     struct msgb *msg, unsigned int length)
 {
+	struct gsm_network *network;
 	struct tlv_parsed tp;
 	struct bss_sccp_connection_data *msc_data;
 	u_int8_t *data;
 	u_int8_t multiplex;
-	int i, found = 0;
+	enum gsm48_chan_mode chan_mode = GSM48_CMODE_SIGN;
+	int i, supported;
 
 	if (!msg->lchan || !msg->lchan->msc_data) {
 		DEBUGP(DMSC, "No lchan/msc_data in cipher mode command.\n");
@@ -302,6 +363,7 @@ static int bssmap_handle_assignm_req(struct sccp_connection *conn,
 	}
 
 	msc_data = msg->lchan->msc_data;
+	network = msg->lchan->ts->trx->bts->network;
 	tlv_parse(&tp, &bss_att_tlvdef, msg->l4h + 1, length - 1, 0, 0);
 
 	if (!TLVP_PRESENT(&tp, GSM0808_IE_CHANNEL_TYPE)) {
@@ -343,20 +405,30 @@ static int bssmap_handle_assignm_req(struct sccp_connection *conn,
 		goto reject;
 	}
 
-	/* go through the list of permitted codecs */
-	for (i = 2; i < TLVP_LEN(&tp, GSM0808_IE_CHANNEL_TYPE); ++i) {
-		if ((data[i] & 0x7f) == GSM0808_PERM_FR2) {
-			found = 1;
-			break;
+	/*
+	 * go through the list of preferred codecs of our gsm network
+	 * and try to find it among the permitted codecs. If we found
+	 * it we will send chan_mode to the right mode and break the
+	 * inner loop. The outer loop will exit due chan_mode having
+	 * the correct value.
+	 */
+	for (supported = 0;
+		chan_mode == GSM48_CMODE_SIGN && supported < network->audio_length;
+		++supported) {
+
+		int perm_val = audio_support_to_gsm88(network->audio_support[supported]);
+		for (i = 2; i < TLVP_LEN(&tp, GSM0808_IE_CHANNEL_TYPE); ++i) {
+			if ((data[i] & 0x7f) == perm_val) {
+				chan_mode = gsm88_to_chan_mode(perm_val);
+				break;
+			} else if ((data[i] & 0x80) == 0x00) {
+				break;
+			}
 		}
-
-		/* last octet, stop */
-		if ((data[i] & 0x80) == 0x00)
-			break;
 	}
 
-	if (!found) {
-		DEBUGP(DMSC, "ChannelType FR2 not supported\n");
+	if (chan_mode == GSM48_CMODE_SIGN) {
+		DEBUGP(DMSC, "No supported audio type found.\n");
 		goto reject;
 	}
 
@@ -366,8 +438,8 @@ static int bssmap_handle_assignm_req(struct sccp_connection *conn,
 	bsc_schedule_timer(&msc_data->T10, GSM0808_T10_VALUE);
 
 	msc_data->rtp_port = rtp_calculate_port(multiplex, rtp_base_port);
-	DEBUGP(DMSC, "Sending ChanModify for speech on: sccp: %p\n", conn);
-	return gsm48_lchan_modify(msg->lchan, GSM48_CMODE_SPEECH_EFR);
+	DEBUGP(DMSC, "Sending ChanModify for speech on: sccp: %p mode: 0x%x\n", conn, chan_mode);
+	return gsm48_lchan_modify(msg->lchan, chan_mode);
 
 reject:
 	gsm0808_send_assignment_failure(msg->lchan,