Bug #3784

osmo-bsc ignores requested channel type in ASSIGNEMENT REQUESTS for signalling channels

Added by tnt 9 months ago. Updated 5 months ago.

Target version:
Start date:
Due date:
% Done:


Spec Reference:


In bssmap_handle_assignm_req , if channel type is of GSM0808_CHAN_SIGN it just creates an a request for a signaling channel but never looks at the ct.ch_rate_type fields to see what kind of channel is really requested. Instead in the assignement fsm and throuh lchan_select_by_chan_mode, it will always assume a signalling channel is a SDCCH.

Also in the assignement fsm, if it sees the current channel mode supports the requested mode (and independently of the channel type requests in ct.ch_rate_type), it will ignore it and not do anything.

    struct gsm0808_channel_type ct;

    ct.ch_indctr = GSM0808_CHAN_SIGN;
    ct.ch_rate_type = GSM0808_SPEECH_FULL_BM; /* libosmocore doesn't actually define constants for signalling mode channels but this one is compatible in value */
    ct.perm_spch[0] = 0; /* spare but must be present ! */
    ct.perm_spch_len = 1;

    msg = gsm0808_create_ass(&ct, NULL, NULL, NULL, NULL);
    osmo_sccp_tx_data_msg(conn->a.scu, conn->a.conn_id, msg);


#1 Updated by laforge 9 months ago

  • Assignee set to laforge

#2 Updated by laforge 9 months ago

let's wait until is merged to avoid clashes...

#3 Updated by laforge 8 months ago

  • Assignee changed from laforge to tnt

#4 Updated by tnt 8 months ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 50

First version of the patch up for review:

#5 Updated by tnt 5 months ago

  • Status changed from In Progress to Resolved

Working in current master.

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