mgcp: add voice muxer support
This patch adds the voice muxer. You can use this to batch RTP
traffic to reduce bandwidth comsuption. Basically, osmux transforms
RTP flows to a compact batch format, that is later on decompacted
to its original form. Port UDP/1984 is used for the muxer traffic
between osmo-bsc_nat and osmo-bsc_mgcp (in the BSC side). This
feature depends on libosmo-netif, which contains the osmux core
support.
Osmux is requested on-demand via the MGCP CRCX/MDCX messages (using
the vendor-specific extension X-Osmux: on) coming from the BSC-NAT,
so you can selectively enable osmux per BSC from one the bsc-nat.cfg
file, so we have a centralized point to enable/disable osmux.
First thing you need to do is to accept requests to use Osmux,
this can be done from VTY interface of osmo-bsc_nat and
osmo-bsc_mgcp by adding the following line:
mgcp
...
osmux on
osmux batch-factor 4
This just initializes the osmux engine. You still have to specify
what BSC uses osmux from osmo-bsc_nat configuration file:
...
bsc 1
osmux on
bsc 2
...
bsc 3
osmux on
In this case, bsc 1 and 3 should use osmux if possible, bsc 2 does
not have osmux enabled.
Thus, you can selectively enable osmux depending on the BSC, and
we have a centralized point for configuration from the bsc-nat to
enable osmux on demand, as suggested by Holger.
At this moment, this patch contains heavy debug logging for each
RTP packet that can be removed later to save cycles.
The RTP ssrc/seqnum/timestamp is randomly allocated for each MDCX that
is received to configure an endpoint.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c b/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
index 3dad396..22b8a35 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_mgcp_utils.c
@@ -262,12 +262,12 @@
int len;
len = snprintf(buf, sizeof(buf),
- "MDCX 23 %x@mgw MGCP 1.0\r\n"
+ "MDCX 23 %x@mgw MGCP 1.0%s\r\n"
"Z: noanswer\r\n"
"\r\n"
"c=IN IP4 %s\r\n"
"m=audio %d RTP/AVP 255\r\n",
- port,
+ port, bsc->cfg->osmux ? "\nX-Osmux: on" : "",
bsc->nat->mgcp_cfg->source_addr,
endp->bts_end.local_port);
if (len < 0) {
@@ -545,6 +545,7 @@
bsc_msg = bsc_mgcp_rewrite((char *) nat->mgcp_msg, nat->mgcp_length,
sccp->bsc_endp, nat->mgcp_cfg->source_addr,
mgcp_endp->bts_end.local_port,
+ nat->mgcp_cfg->osmux ? sccp->bsc->cfg->osmux : 0,
&mgcp_endp->net_end.payload_type);
if (!bsc_msg) {
LOGP(DMGCP, LOGL_ERROR, "Failed to patch the msg.\n");
@@ -559,6 +560,16 @@
/* we need to update some bits */
if (state == MGCP_ENDP_CRCX) {
struct sockaddr_in sock;
+ struct mgcp_endpoint *endp = &nat->mgcp_cfg->trunk.endpoints[endpoint];
+
+ if (nat->mgcp_cfg->osmux ? sccp->bsc->cfg->osmux : 0) {
+ if (osmux_enable_endpoint(endp, OSMUX_ROLE_BSC_NAT) < 0) {
+ LOGP(DMGCP, LOGL_ERROR,
+ "Could not activate osmux in endpoint %d\n",
+ ENDPOINT_NUMBER(endp));
+ }
+ }
+
socklen_t len = sizeof(sock);
if (getpeername(sccp->bsc->write_queue.bfd.fd, (struct sockaddr *) &sock, &len) != 0) {
LOGP(DMGCP, LOGL_ERROR, "Can not get the peername...%d/%s\n",
@@ -687,8 +698,8 @@
output = bsc_mgcp_rewrite((char * ) msg->l2h, msgb_l2len(msg), -1,
bsc->nat->mgcp_cfg->source_addr,
endp->net_end.local_port,
+ bsc->nat->mgcp_cfg->osmux ? bsc_endp->bsc->cfg->osmux : 0,
&endp->bts_end.payload_type);
-
if (!output) {
LOGP(DMGCP, LOGL_ERROR, "Failed to rewrite MGCP msg.\n");
return;
@@ -727,7 +738,7 @@
* Create a new MGCPCommand based on the input and endpoint from a message
*/
static void patch_mgcp(struct msgb *output, const char *op, const char *tok,
- int endp, int len, int cr)
+ int endp, int len, int cr, int osmux)
{
int slen;
int ret;
@@ -741,14 +752,15 @@
return;
}
- slen = sprintf((char *) output->l3h, "%s %s %x@mgw MGCP 1.0%s",
- op, buf, endp, cr ? "\r\n" : "\n");
+ slen = sprintf((char *) output->l3h, "%s %s %x@mgw MGCP 1.0%s%s",
+ op, buf, endp, osmux ? "\nX-Osmux: on" : "",
+ cr ? "\r\n" : "\n");
output->l3h = msgb_put(output, slen);
}
/* we need to replace some strings... */
struct msgb *bsc_mgcp_rewrite(char *input, int length, int endpoint,
- const char *ip, int port,
+ const char *ip, int port, int osmux,
int *payload_type)
{
static const char crcx_str[] = "CRCX ";
@@ -787,11 +799,11 @@
cr = len > 0 && token[len - 1] == '\r';
if (strncmp(crcx_str, token, (sizeof crcx_str) - 1) == 0) {
- patch_mgcp(output, "CRCX", token, endpoint, len, cr);
+ patch_mgcp(output, "CRCX", token, endpoint, len, cr, osmux);
} else if (strncmp(dlcx_str, token, (sizeof dlcx_str) - 1) == 0) {
- patch_mgcp(output, "DLCX", token, endpoint, len, cr);
+ patch_mgcp(output, "DLCX", token, endpoint, len, cr, 0);
} else if (strncmp(mdcx_str, token, (sizeof mdcx_str) - 1) == 0) {
- patch_mgcp(output, "MDCX", token, endpoint, len, cr);
+ patch_mgcp(output, "MDCX", token, endpoint, len, cr, osmux);
} else if (strncmp(ip_str, token, (sizeof ip_str) - 1) == 0) {
output->l3h = msgb_put(output, strlen(ip_str));
memcpy(output->l3h, ip_str, strlen(ip_str));