Date: Thu, 16 Jul 2020 18:50:36 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 248024] Bluetooth L2CAP socket should not use automatically flushable PDUs (on LE at least) Message-ID: <bug-248024-227@https.bugs.freebsd.org/bugzilla/>
next in thread | raw e-mail | index | archive | help
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D248024 Bug ID: 248024 Summary: Bluetooth L2CAP socket should not use automatically flushable PDUs (on LE at least) Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: greg@unrelenting.technology So I've been debugging why a certain BLE device (https://github.com/open-homeautomation/miflora) did not respond to my comm= ands on FreeBSD. (bug 248015 for the ability to talk ACL via raw HCI socket was needed for t= hat debugging.) Replaying the ACL packet Linux was sending via the raw HCI socket I do get replies. Sending its L2CAP payload via an L2CAP socket.. no reply. Differen= ce? One bit: (good) 02 00 00 0b 00 07 00 04 00 10 01 00 ff ff 00 28 (bad) 02 00 20 0b 00 07 00 04 00 10 01 00 ff ff 00 28 ^ that's the PB flag set to 2! So turns out ng_l2cap_lp_send does `flag =3D NG_HCI_PACKET_START`. But our NG_HCI_PACKET_START (2) doesn't just mean "packet start"! According to the Bluetooth Core Spec v5.2 (Vol 4, Part E, 5.4.2, page 1893)= it means "First automatically flushable packet of a higher layer message (star= t of an automatically flushable L2CAP PDU)" and it's *not allowed for LE*! The laziest solution would be `flag =3D 0`, where 0 means "First non-automatically-flushable packet of a higher layer message (start of a non-automatically-flushable L2CAP PDU) from Host to Controller". But then there's the question: is there any benefit from the automatic flus= hing thing on Bluetooth Classic?? Maybe we should only use 0 on LE? --=20 You are receiving this mail because: You are the assignee for the bug.=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-248024-227>