OsmocomBB

The modem app is currently sending hard-coded MS RACap to the PCU. It's hard-coded in libosmo-gprs-rlcmac:

/* 11.2.16 Packet Resource Request */
void gprs_rlcmac_enc_prepare_pkt_resource_req(RlcMacUplink_t *block,
                                              struct gprs_rlcmac_ul_tbf *ul_tbf,
                                              enum gprs_rlcmac_access_type acc_type)
{
        Packet_Resource_Request_t *req;
        struct gprs_rlcmac_entity *gre = ul_tbf->tbf.gre;

        memset(block, 0, sizeof(*block));

        req = &block->u.Packet_Resource_Request;
        req->MESSAGE_TYPE = OSMO_GPRS_RLCMAC_UL_MSGT_PACKET_RESOURCE_REQUEST;

        /* ... */

        req->ID.UnionType = 1; /* Use TLLI */
        req->ID.u.TLLI = gre->tlli; /* Use TLLI */
        req->Exist_MS_Radio_Access_capability2 = 1;

        req->MS_Radio_Access_capability2.Count_MS_RA_capability_value = 1;
        /* TODO: fill Content_t: */
        /* req->MS_Radio_Access_capability2.MS_RA_capability_value[0].Content.* */

We definitely want to send something more meaningful than all zeroes.

• There needs to be a way (API) to "tell" libosmo-gprs-rlcmac which MS RACap to use.
• We may also want to make some parts of the RACap configurable via the VTY.