Hi Syam, > >> > If we register a uuid other than uuid16, especially custom 128 bit uuid > >> > then nothing is updated in the EIR and it was broken. > >> > > >> > After registering a 16 bit uuid. ex: "sdptool add SP", we can see the > >> > uuid in the EIR as below. > >> > < 0000: 01 52 0c f1 00 08 09 52 65 64 77 6f 6f 64 15 03 .R.....Redwood.. > >> > 0010: 01 11 32 11 2f 11 06 11 05 11 0a 11 0e 11 0c 11 ..2./........... > >> > 0020: 1f 11 12 11 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00f0: 00 00 00 00 00 ..... > >> > > 0000: 04 0e 04 01 52 0c 00 ....R.. > >> > > >> > But after register a user defined 128 bit uuid, nothing is > >> > updated in the EIR. > >> > > >> > < 0000: 01 52 0c f1 00 08 09 52 65 64 77 6f 6f 64 00 00 .R.....Redwood.. > >> > 0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> > 00f0: 00 00 00 00 00 ..... > >> > > 0000: 04 0e 04 01 52 0c 00 ....R.. > >> > > >> > With this fix, we can see the EIR is updated properly. > >> > > >> > Signed-off-by: Syam Sidhardhan <s.syam@xxxxxxxxxxx> > >> > --- > >> > net/bluetooth/mgmt.c | 2 -- > >> > 1 file changed, 2 deletions(-) > >> > > >> > diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c > >> > index f559b96..512a3f5 100644 > >> > --- a/net/bluetooth/mgmt.c > >> > +++ b/net/bluetooth/mgmt.c > >> > @@ -514,8 +514,6 @@ static void create_eir(struct hci_dev *hdev, u8 *data) > >> > u16 uuid16; > >> > > >> > uuid16 = get_uuid16(uuid->uuid); > >> > - if (uuid16 == 0) > >> > - return; > >> > > >> > if (uuid16 < 0x1100) > >> > continue; > >> > >> Nak. The bug is real and should be fixed but your fix is wrong. The > >> right fix it to convert this return statement into a continue statement > >> since we do still want to check for a 0 return value from get_uuid16. > >> > > Since the next statements (uuid16 < 0x1100) indirectly do this logic, > I intentionally removed it in order to avoid duplication. > Probably for more clarity and readability, I can do it as per your > suggestion. > > >> Along with this patch please prepare another one to increment the mgmt > >> revision. These two should go together to upstream trees so that we can > >> introduce a check in user space to know whether it's safe to pass > >> non-16bit UUIDs to the kernel or not. > > > Ok. > > I want a fix that introduces also support for 32-bit and 128-bit UUIDs > > now. No paper over the hole fixing here. > > > > As per the specification, "To reduce interference, the host should try > to minimize the amount of EIR data such that the baseband can use > a 1-slot or 3-slot EIR packet. This is advantageous because it reduces > interference and maximizes the probability that the EIR packet will be > received." > > Does the addition of 128-bit and 32-bit uuid decreases the probability of the > reception of EIR packet, if any application register more of these types? that is not the point here. If you want to put a 128-bit UUID into the EIR data, then you should be able to. Let bluetoothd make the decision on what to give the kernel and what not. Regards Marcel -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
