[PATCH BlueZ bluez v2 1/2] bass: support for encrypted broadcast source

[Yang Li via B4 Relay <devnull+yang.li.amlogic.com@xxxxxxxxxx>]

From: Yang Li <yang.li@xxxxxxxxxxx>

If the BIS is encrypted as indicated in the BIG Info Report, the
broadcast code needs to be requested from the Assistant.

step 1: Broadcast_Code required
  > HCI Event: LE Meta Event (0x3e) plen 20                 #631 [hci0] 27.176606
        LE Broadcast Isochronous Group Info Advertising Report (0x22)
          Sync Handle: 0x0000
          Number BIS: 2
          NSE: 8
          ISO Interval: 20.00 msec (0x0010)
          BN: 2
          PTO: 2
          IRC: 2
          Maximum PDU: 60
          SDU Interval: 10000 us (0x002710)
          Maximum SDU: 60
          PHY: LE 2M (0x02)
          Framing: Unframed (0x00)
          Encryption: 0x01
  < ACL Data TX: Handle 16 flags 0x00 dlen 44               #633 [hci0] 27.184478
        ATT: Handle Value Notification (0x1b) len 39
          Handle: 0x005f Type: Broadcast Receive State (0x2bc8)
            Data[37]: 01016698a411bb13019f103b02010100000000110d03506978656c20395f32303938020502
            Source_ID: 1
            Source_Address_Type: 1
            Source_Address: 13:BB:11:A4:98:66
            Source_Adv_SID: 1
            Broadcast_ID: 0x3b109f
            PA_Sync_State: Synchronized to PA
            BIG_Encryption: Broadcast_Code required
            Num_Subgroups: 1
            Subgroup #0:
              BIS_Sync State: 0x00000000
              Metadata: #0: len 0x0d type 0x03
              Metadata:   50 69 78 65 6c 20 39 5f 32 30 39 38              Pixel 9_2098
              Metadata: #1: len 0x02 type 0x05
              Metadata:   02
  > ACL Data RX: Handle 16 flags 0x02 dlen 25               #636 [hci0] 27.455744
        ATT: Write Command (0x52) len 20
          Handle: 0x0065 Type: Broadcast Audio Scan Control Point (0x2bc7)
            Data[18]: 04013a4931614b3a2b7c4b7431722b666724
              Opcode: Set Broadcast_Code (0x04)
              Source_ID: 1
              Broadcast_Code[16]: 3a4931614b3a2b7c4b7431722b666724

step 2: Set Broadcast Code when BIG Create Sync
  < HCI Command: LE Broadcast Isoc.. (0x08|0x006b) plen 26  #641 [hci0] 27.669211
          BIG Handle: 0x00
          BIG Sync Handle: 0x0000
          Encryption: Encrypted (0x01)
          Broadcast Code[16]: 3a4931614b3a2b7c4b7431722b666724
          Maximum Number Subevents: 0x00
          Timeout: 20000 ms (0x07d0)
          Number of BIS: 2
          BIS ID: 0x01
          BIS ID: 0x02

Fixes: https://github.com/bluez/bluez/issues/1306
---
 profiles/audio/bass.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/profiles/audio/bass.c b/profiles/audio/bass.c
index b27a3fc12..2cda00b69 100644
--- a/profiles/audio/bass.c
+++ b/profiles/audio/bass.c
@@ -427,13 +427,45 @@ static void bap_state_changed(struct bt_bap_stream *stream, uint8_t old_state,
 	}
 }
 
+static void bass_req_bcode_cb(void *user_data, int err)
+{
+	struct bass_setup *setup = user_data;
+
+	if (!err) {
+		if (asprintf(&setup->path, "%s/bis%d",
+			device_get_path(setup->dg->device),
+			setup->bis) < 0)
+			return;
+
+		bt_bap_stream_set_user_data(setup->stream, setup->path);
+
+		bt_bap_stream_config(setup->stream, &setup->qos,
+				setup->config, NULL, NULL);
+		bt_bap_stream_metadata(setup->stream, setup->meta,
+				NULL, NULL);
+	}
+}
+
 static void setup_configure_stream(struct bass_setup *setup)
 {
+	uint8_t empty_bcode[BT_BASS_BCAST_CODE_SIZE] = {0};
+
 	setup->stream = bt_bap_stream_new(setup->dg->bap, setup->lpac, NULL,
 					&setup->qos, setup->config);
 	if (!setup->stream)
 		return;
 
+	/* Before configuring the stream, check whether it is encrypted.
+	 * If so, request the broadcast code from the client.
+	 */
+	if ((setup->qos.bcast.encryption) &&
+	    (!memcmp(setup->qos.bcast.bcode->iov_base,
+		     empty_bcode,
+		     sizeof(empty_bcode)))) {
+		bass_req_bcode(setup->stream, bass_req_bcode_cb, setup, NULL);
+		return;
+	}
+
 	if (asprintf(&setup->path, "%s/bis%d",
 			device_get_path(setup->dg->device),
 			setup->bis) < 0)

-- 
2.42.0