[PATCH 2/2] Don't connect channels of incompatible voice codec

This is merely a historical archive of years 2008-2021, before the migration to mailman3.

A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/OpenBSC@lists.osmocom.org/.

Holger Freyther holger at freyther.de
Wed Mar 23 19:05:25 UTC 2016


> On 23 Mar 2016, at 19:14, msuraev at sysmocom.de wrote:
> 
> From: Max <msuraev at sysmocom.de>
> 
> Note: ideally this situation should not happen - we should check
> channel compatibility before paging 2nd leg of the call.
> 
> 
> 
> +	if (lt != rt) {


lt / rt is not declared in this patch (and yes, it belongs into this one. But channel type is still not good enough. Let's assume I have a TCH/H and a TCH/F and I use AMR5.9 on both of these channels. Then the voice codec (and its parameters) are compatible.

I don't know the specific ticket and ultimate goal but I think either you check for codec compatibility or change the wording to refer only to channel type and leave the actual voice codec incompat for another day.





> +		LOGP(DCC, LOGL_ERROR, "Cannot patch through call with different"
> +		     " channel types: local = %s, remote = %s\n",
> +		     osmo_gsm48_chan_type2str(lt), osmo_gsm48_chan_type2str(rt));
> +		return -EBADSLT;
> +	}
> +
> 	// todo: map between different bts types
> 	switch (bts->type) {
> 	case GSM_BTS_TYPE_NANOBTS:
> @@ -1851,6 +1858,26 @@ static void gsm48_cc_timeout(void *arg)
> 
> }
> 
> +static inline void disconnect_bridge(struct gsm_network *net,
> +				    struct gsm_mncc_bridge *bridge)
> +{
> +	struct gsm_trans *trans0 = trans_find_by_callref(net, bridge->callref[0]);
> +	struct gsm_trans *trans1 = trans_find_by_callref(net, bridge->callref[1]);
> +	struct gsm_mncc mx_rel;
> +	if (!trans0 || !trans1)
> +		return;


Can you please elaborate about the intention of this method? You try to undo a failed mapping and do this by disconnecting the call? Is that the right thing to do? Has there been any side effect by the call of tch_map?

In the long run should there be a MNCC_BRIDGE_REJ answer to the MNCC_BRIDGE call?


> @@ -3220,7 +3247,12 @@ int mncc_tx_to_cc(struct gsm_network *net, int msg_type, void *arg)
> 	/* handle special messages */
> 	switch(msg_type) {
> 	case MNCC_BRIDGE:
> -		return tch_bridge(net, arg);
> +		rc = tch_bridge(net, arg);
> +		if (rc < 0) {
> +			DEBUGP(DCC, "Failed to bridge TCH: %s\n", strerror(-rc));

Do you think it makes sense to include both callrefs?

holger




More information about the OpenBSC mailing list