OsmocomBB

Right now osmocom-bb's modem app is submitting a hardcoded fn=0 to the RLC/MAC layer when submitting CCCH-DATA.ind:

static int forward_to_rlcmac(struct osmocom_ms *ms, struct msgb *msg)
{
    struct osmo_gprs_rlcmac_prim *rlcmac_prim;

    /* Forward SI13 to RLC/MAC layer */
    rlcmac_prim = osmo_gprs_rlcmac_prim_alloc_l1ctl_ccch_data_ind(0 /* TODO: fn */, msgb_l3(msg));
    return osmo_gprs_rlcmac_prim_lower_up(rlcmac_prim);
}

This is of course wrong and has to be fixed to provide the current FN from the scheduler, since RLC/MAC needs it for instance when receiving a CCCH ImmAss[PktUlAss[SingleBlkAlloc]] which contains an RFN, and which hence needs to be transformed to an absolute fn using curr_fn + rfn.