[PATCH 4/9] Add support for AMR frames to MNCC/RTP interface

[Andreas Eversberg]

AMR rate is currently fixed to 5.9k.
---
 openbsc/src/libmsc/gsm_04_08.c  |  1 +
 openbsc/src/libtrau/rtp_proxy.c | 24 +++++++++++++++++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c
index df93433..a0650ab 100644
--- a/openbsc/src/libmsc/gsm_04_08.c
+++ b/openbsc/src/libmsc/gsm_04_08.c
@@ -2953,6 +2953,7 @@ int mncc_tx_to_cc(struct gsm_network *net, int msg_type, 
void *arg)
        case GSM_TCHF_FRAME:
        case GSM_TCHF_FRAME_EFR:
        case GSM_TCHH_FRAME:
+       case GSM_TCH_FRAME_AMR:
                /* Find callref */
                trans = trans_find_by_callref(net, data->callref);
                if (!trans) {
diff --git a/openbsc/src/libtrau/rtp_proxy.c b/openbsc/src/libtrau/rtp_proxy.c
index 143bfa0..9c16a95 100644
--- a/openbsc/src/libtrau/rtp_proxy.c
+++ b/openbsc/src/libtrau/rtp_proxy.c
@@ -116,6 +116,7 @@ static int rtp_decode(struct msgb *msg, uint32_t callref, 
struct msgb **data)
        int payload_len;
        int msg_type;
        int x_len;
+       int is_amr = 0;
 
        if (msg->len < 12) {
                DEBUGPC(DLMUX, "received RTP frame too short (len = %d)\n",
@@ -192,21 +193,26 @@ static int rtp_decode(struct msgb *msg, uint32_t callref, 
struct msgb **data)
                        return -EINVAL;
                }
                break;
+       case RTP_PT_AMR:
+               is_amr = 1;
+               break;
        default:
                DEBUGPC(DLMUX, "received RTP frame with unknown payload "
                        "type %d\n", rtph->payload_type);
                return -EINVAL;
        }
 
-       new_msg = msgb_alloc(sizeof(struct gsm_data_frame) + payload_len,
-                               "GSM-DATA");
+       new_msg = msgb_alloc(sizeof(struct gsm_data_frame) + payload_len +
+               is_amr, "GSM-DATA");
        if (!new_msg)
                return -ENOMEM;
        frame = (struct gsm_data_frame *)(new_msg->data);
        frame->msg_type = msg_type;
        frame->callref = callref;
-       memcpy(frame->data, payload, payload_len);
-       msgb_put(new_msg, sizeof(struct gsm_data_frame) + payload_len);
+       if (is_amr)
+               frame->data[0] = payload_len;
+       memcpy(frame->data + is_amr, payload, payload_len);
+       msgb_put(new_msg, sizeof(struct gsm_data_frame) + is_amr + payload_len);
 
        *data = new_msg;
        return 0;
@@ -239,6 +245,7 @@ int rtp_send_frame(struct rtp_socket *rs, struct 
gsm_data_frame *frame)
        int payload_type;
        int payload_len;
        int duration; /* in samples */
+       int is_amr = 0;
 
        if (rs->tx_action != RTP_SEND_DOWNSTREAM) {
                /* initialize sequences */
@@ -264,6 +271,12 @@ int rtp_send_frame(struct rtp_socket *rs, struct 
gsm_data_frame *frame)
                payload_len = RTP_LEN_GSM_HALF;
                duration = RTP_GSM_DURATION;
                break;
+       case GSM_TCH_FRAME_AMR:
+               payload_type = RTP_PT_AMR;
+               payload_len = frame->data[0];
+               duration = RTP_GSM_DURATION;
+               is_amr = 1;
+               break;
        default:
                DEBUGPC(DLMUX, "unsupported message type %d\n",
                        frame->msg_type);
@@ -305,7 +318,8 @@ int rtp_send_frame(struct rtp_socket *rs, struct 
gsm_data_frame *frame)
        rtph->timestamp = htonl(rs->transmit.timestamp);
        rs->transmit.timestamp += duration;
        rtph->ssrc = htonl(rs->transmit.ssrc);
-       memcpy(msg->data + sizeof(struct rtp_hdr), frame->data, payload_len);
+       memcpy(msg->data + sizeof(struct rtp_hdr), frame->data + is_amr,
+               payload_len);
        msgb_put(msg, sizeof(struct rtp_hdr) + payload_len);
        msgb_enqueue(&rss->tx_queue, msg);
        rss->bfd.when |= BSC_FD_WRITE;
-- 
1.8.1.5