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Jacob Erlbeck jerlbeck at sysmocom.deThis adds datastructures and a VTY frontend to configure the
different type of RTP header patching: SSRC and timestamp.
Note that timestamp patching is not yet implemented.
Sponsored-by: On-Waves ehf
---
openbsc/include/openbsc/mgcp.h | 4 +++
openbsc/include/openbsc/mgcp_internal.h | 10 ++++--
openbsc/src/libmgcp/mgcp_network.c | 2 +-
openbsc/src/libmgcp/mgcp_protocol.c | 15 ++++++++-
openbsc/src/libmgcp/mgcp_vty.c | 56 ++++++++++++++++++++++++++++++-
openbsc/tests/mgcp/mgcp_test.c | 6 +++-
6 files changed, 86 insertions(+), 7 deletions(-)
diff --git a/openbsc/include/openbsc/mgcp.h b/openbsc/include/openbsc/mgcp.h
index 4e22e0f..8ab52ce 100644
--- a/openbsc/include/openbsc/mgcp.h
+++ b/openbsc/include/openbsc/mgcp.h
@@ -118,6 +118,10 @@ struct mgcp_trunk_config {
int omit_rtcp;
+ /* RTP patching */
+ int force_constant_ssrc; /* 0: don't, 1: once */
+ int force_constant_timing;
+
/* spec handling */
int force_realloc;
diff --git a/openbsc/include/openbsc/mgcp_internal.h b/openbsc/include/openbsc/mgcp_internal.h
index 0b52c1c..02e193d 100644
--- a/openbsc/include/openbsc/mgcp_internal.h
+++ b/openbsc/include/openbsc/mgcp_internal.h
@@ -83,6 +83,10 @@ struct mgcp_rtp_end {
int frames_per_packet;
char *fmtp_extra;
+ /* RTP patching */
+ int force_constant_ssrc;
+ int force_constant_timing;
+
/*
* Each end has a socket...
*/
@@ -142,9 +146,6 @@ struct mgcp_endpoint {
struct mgcp_rtp_state net_state;
struct mgcp_rtp_state bts_state;
- /* SSRC/seq/ts patching for loop */
- int allow_patch;
-
/* fields for re-transmission */
char *last_trans;
char *last_response;
@@ -176,6 +177,9 @@ static inline int endp_back_channel(int endpoint)
struct mgcp_trunk_config *mgcp_trunk_alloc(struct mgcp_config *cfg, int index);
struct mgcp_trunk_config *mgcp_trunk_num(struct mgcp_config *cfg, int index);
+void mgcp_rtp_end_config(struct mgcp_endpoint *endp, int expect_ssrc_change,
+ struct mgcp_rtp_end *rtp);
+
void mgcp_state_calc_loss(struct mgcp_rtp_state *s, struct mgcp_rtp_end *,
uint32_t *expected, int *loss);
uint32_t mgcp_state_calc_jitter(struct mgcp_rtp_state *);
diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index 53f1a20..367cebd 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -264,7 +264,7 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
state->seq_offset = (state->out_stream.last_seq + 1) - seq;
state->timestamp_offset =
(state->out_stream.last_timestamp + tsdelta) - timestamp;
- state->patch = endp->allow_patch;
+ state->patch = rtp_end->force_constant_ssrc;
LOGP(DMGCP, LOGL_NOTICE,
"The SSRC changed on 0x%x SSRC: %u offset: %d tsdelta: %d "
"from %s:%d in %d\n",
diff --git a/openbsc/src/libmgcp/mgcp_protocol.c b/openbsc/src/libmgcp/mgcp_protocol.c
index a0b905d..d7e4745 100644
--- a/openbsc/src/libmgcp/mgcp_protocol.c
+++ b/openbsc/src/libmgcp/mgcp_protocol.c
@@ -614,6 +614,15 @@ static int parse_sdp_data(struct mgcp_rtp_end *rtp, struct mgcp_parse_data *p)
return found_media;
}
+void mgcp_rtp_end_config(struct mgcp_endpoint *endp, int expect_ssrc_change,
+ struct mgcp_rtp_end *rtp)
+{
+ struct mgcp_trunk_config *tcfg = endp->tcfg;
+
+ rtp->force_constant_timing = tcfg->force_constant_timing;
+ rtp->force_constant_ssrc = tcfg->force_constant_ssrc;
+}
+
static struct msgb *handle_create_con(struct mgcp_parse_data *p)
{
struct mgcp_trunk_config *tcfg;
@@ -688,6 +697,8 @@ mgcp_header_done:
/* initialize */
endp->net_end.rtp_port = endp->net_end.rtcp_port = endp->bts_end.rtp_port = endp->bts_end.rtcp_port = 0;
+ mgcp_rtp_end_config(endp, 0, &endp->net_end);
+ mgcp_rtp_end_config(endp, 0, &endp->bts_end);
/* set to zero until we get the info */
memset(&endp->net_end.addr, 0, sizeof(endp->net_end.addr));
@@ -825,6 +836,9 @@ static struct msgb *handle_modify_con(struct mgcp_parse_data *p)
}
}
+ mgcp_rtp_end_config(endp, 1, &endp->net_end);
+ mgcp_rtp_end_config(endp, 1, &endp->bts_end);
+
/* modify */
LOGP(DMGCP, LOGL_DEBUG, "Modified endpoint on: 0x%x Server: %s:%u\n",
ENDPOINT_NUMBER(endp), inet_ntoa(endp->net_end.addr), ntohs(endp->net_end.rtp_port));
@@ -1121,7 +1135,6 @@ void mgcp_free_endp(struct mgcp_endpoint *endp)
memset(&endp->bts_state, 0, sizeof(endp->bts_state));
endp->conn_mode = endp->orig_mode = MGCP_CONN_NONE;
- endp->allow_patch = 0;
memset(&endp->taps, 0, sizeof(endp->taps));
}
diff --git a/openbsc/src/libmgcp/mgcp_vty.c b/openbsc/src/libmgcp/mgcp_vty.c
index 5aeb393..16b973f 100644
--- a/openbsc/src/libmgcp/mgcp_vty.c
+++ b/openbsc/src/libmgcp/mgcp_vty.c
@@ -31,6 +31,7 @@
#include <string.h>
#define RTCP_OMIT_STR "Drop RTCP packets in both directions\n"
+#define RTP_PATCH_STR "Modify RTP packet header in both directions\n"
static struct mgcp_config *g_cfg = NULL;
@@ -511,6 +512,13 @@ static int config_write_trunk(struct vty *vty)
vty_out(vty, " rtcp-omit%s", VTY_NEWLINE);
else
vty_out(vty, " no rtcp-omit%s", VTY_NEWLINE);
+ if (trunk->force_constant_ssrc || trunk->force_constant_timing) {
+ vty_out(vty, " rtp-patch ssrc %d%s",
+ trunk->force_constant_ssrc, VTY_NEWLINE);
+ vty_out(vty, " rtp-patch timestamp %d%s",
+ trunk->force_constant_timing, VTY_NEWLINE);
+ } else
+ vty_out(vty, " no rtp-patch%s", VTY_NEWLINE);
if (trunk->audio_fmtp_extra)
vty_out(vty, " sdp audio fmtp-extra %s%s",
trunk->audio_fmtp_extra, VTY_NEWLINE);
@@ -599,6 +607,46 @@ DEFUN(cfg_trunk_no_omit_rtcp,
return CMD_SUCCESS;
}
+DEFUN(cfg_trunk_patch_rtp_ssrc,
+ cfg_trunk_patch_rtp_ssrc_cmd,
+ "rtp-patch ssrc (0|1)",
+ RTP_PATCH_STR
+ "Force a fixed SSRC\n"
+ "Disable\n"
+ "Enable\n"
+ )
+{
+ struct mgcp_trunk_config *trunk = vty->index;
+ trunk->force_constant_ssrc = atoi(argv[0]);
+ return CMD_SUCCESS;
+}
+
+DEFUN(cfg_trunk_patch_rtp_ts,
+ cfg_trunk_patch_rtp_ts_cmd,
+ "rtp-patch timestamp (0|1)",
+ RTP_PATCH_STR
+ "Adjust RTP timestamp\n"
+ "Disable\n"
+ "Enable\n"
+ )
+{
+ struct mgcp_trunk_config *trunk = vty->index;
+ trunk->force_constant_timing = atoi(argv[0]);
+ return CMD_SUCCESS;
+}
+
+DEFUN(cfg_trunk_no_patch_rtp,
+ cfg_trunk_no_patch_rtp_cmd,
+ "no rtp-patch",
+ NO_STR RTP_PATCH_STR)
+{
+ struct mgcp_trunk_config *trunk = vty->index;
+ trunk->force_constant_ssrc = 0;
+ trunk->force_constant_timing = 0;
+ return CMD_SUCCESS;
+}
+
+
DEFUN(loop_endp,
loop_endp_cmd,
"loop-endpoint <0-64> NAME (0|1)",
@@ -636,7 +684,10 @@ DEFUN(loop_endp,
endp->conn_mode = MGCP_CONN_LOOPBACK;
else
endp->conn_mode = endp->orig_mode;
- endp->allow_patch = 1;
+
+ /* Handle it like a MDCX, switch on SSRC patching if enabled */
+ mgcp_rtp_end_config(endp, 1, &endp->bts_end);
+ mgcp_rtp_end_config(endp, 1, &endp->net_end);
return CMD_SUCCESS;
}
@@ -839,6 +890,9 @@ int mgcp_vty_init(void)
install_element(TRUNK_NODE, &cfg_trunk_loop_cmd);
install_element(TRUNK_NODE, &cfg_trunk_omit_rtcp_cmd);
install_element(TRUNK_NODE, &cfg_trunk_no_omit_rtcp_cmd);
+ install_element(TRUNK_NODE, &cfg_trunk_patch_rtp_ssrc_cmd);
+ install_element(TRUNK_NODE, &cfg_trunk_patch_rtp_ts_cmd);
+ install_element(TRUNK_NODE, &cfg_trunk_no_patch_rtp_cmd);
install_element(TRUNK_NODE, &cfg_trunk_sdp_fmtp_extra_cmd);
return 0;
diff --git a/openbsc/tests/mgcp/mgcp_test.c b/openbsc/tests/mgcp/mgcp_test.c
index 8e130bb..908773a 100644
--- a/openbsc/tests/mgcp/mgcp_test.c
+++ b/openbsc/tests/mgcp/mgcp_test.c
@@ -558,6 +558,9 @@ static void test_packet_error_detection(int patch_ssrc, int patch_ts)
trunk.number_endpoints = 1;
trunk.endpoints = &endp;
+ trunk.force_constant_ssrc = patch_ssrc;
+ trunk.force_constant_timing = patch_ts;
+
endp.tcfg = &trunk;
/* This doesn't free endp but resets/frees all fields of the structure
@@ -568,7 +571,6 @@ static void test_packet_error_detection(int patch_ssrc, int patch_ts)
mgcp_free_endp(&endp);
rtp->payload_type = 98;
- endp.allow_patch = patch_ssrc;
for (i = 0; i < ARRAY_SIZE(test_rtp_packets1); ++i) {
struct rtp_packet_info *info = test_rtp_packets1 + i;
@@ -577,6 +579,8 @@ static void test_packet_error_detection(int patch_ssrc, int patch_ts)
OSMO_ASSERT(info->len >= 0);
memmove(buffer, info->data, info->len);
+ mgcp_rtp_end_config(&endp, 1, rtp);
+
mgcp_patch_and_count(&endp, &state, rtp, &addr,
buffer, info->len);
--
1.7.9.5