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authorNeels Hofmeyr <nhofmeyr@sysmocom.de>2017-03-16 16:14:34 +0100
committerNeels Hofmeyr <nhofmeyr@sysmocom.de>2017-05-09 00:27:49 +0200
commit37fe7ae5f2ca1379e82689d6a6893256000b061c (patch)
treed200faad9757a94bb08dc81e0c656e9b3c731312
parent2a1c1fe7b416b8db61ee952ce1178f638dd08c54 (diff)
mgcp: hack RAB success from nano3G: patch first RTP payload
The ip.access nano3G needs the first RTP payload's first two bytes to read hex 'e400', or it will reject the RAB assignment. Add flag patched_first_rtp_payload to mgcp_rtp_state to detect the first RTP payload on a stream, and overwrite its first bytes with e400. This should probably be configurable, but seems to not harm other femto cells (as long as we patch only the first RTP payload in each stream). Only do this when sending to the BTS side. Change-Id: I31a4475f42d59fd5704d52ee6e473e270db6d779
-rw-r--r--openbsc/include/openbsc/mgcp_internal.h1
-rw-r--r--openbsc/src/libmgcp/mgcp_network.c7
2 files changed, 8 insertions, 0 deletions
diff --git a/openbsc/include/openbsc/mgcp_internal.h b/openbsc/include/openbsc/mgcp_internal.h
index b58eb9b58..4e215b8f1 100644
--- a/openbsc/include/openbsc/mgcp_internal.h
+++ b/openbsc/include/openbsc/mgcp_internal.h
@@ -64,6 +64,7 @@ struct mgcp_rtp_state {
uint32_t stats_jitter;
int32_t stats_transit;
int stats_cycles;
+ bool patched_first_rtp_payload;
};
struct mgcp_rtp_codec {
diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index c9fe17973..a1c7e85fc 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -667,6 +667,13 @@ int mgcp_send(struct mgcp_endpoint *endp, int dest, int is_rtp,
forward_data(rtp_end->rtp.fd, &endp->taps[tap_idx],
buf, len);
+ if (tap_idx == MGCP_TAP_BTS_OUT
+ && !rtp_state->patched_first_rtp_payload) {
+ uint8_t *data = (uint8_t*)&buf[12];
+ osmo_hexparse("e400", data, 2);
+ rtp_state->patched_first_rtp_payload = true;
+ }
+
rc = mgcp_udp_send(rtp_end->rtp.fd,
&rtp_end->addr,
rtp_end->rtp_port, buf, len);