Re: bluetooth from guest?

On Tue, Aug 30, 2016 at 11:01:39AM +0200, Tor Rune Skoglund wrote:
> Hi List,

Hey Tor Rune!

> any suggestion on the best way to let a guest address and 
> fully acontrol specified bluetooth device?

You probably need to modify the kernel to allow this in
a safe way.

> It seems like hcitool creates a socket, and when it tries
> to write to it, it fails - as expected. (The relevant part
> of strace is below.)

A raw socket with a bluetooth protocol filter.

> In other cases where we need hardware access to a device 
> from a guest, we have just created the corresponding device
> node inside the guest, but I cannot see that the "raw"
> bluetooth device is present as a device node in /dev ... (?)

Bluetooth, like IRDA or CAN is very similar to 'normal'
networking, so it comes with all the problems associated
with 'assigning' a 'networking' device to a guest ...

> (I'm no expert on this, so I am sure that I miss some-
> thing.... ;)

> Any pointers before I start RTFM ? ;)

To be honest, I haven't even tried to do something like
this before, and I haven't heard of anybody who did it
either, so mostly undiscovered country I guess ...

Let us know what you find out,
and all the best,
Herbert

> - Tor Rune Skoglund, [email protected]


> socket(PF_BLUETOOTH, SOCK_RAW|SOCK_CLOEXEC, 1) = 3
> ioctl(3, 0x800448d3, 0xbff1f650)        = 0
> close(3)                                = 0
> socket(PF_BLUETOOTH, SOCK_RAW|SOCK_CLOEXEC, 1) = 3
> ioctl(3, 0x800448d3, 0xbff1f690)        = 0
> close(3)                                = 0
> socket(PF_BLUETOOTH, SOCK_RAW|SOCK_CLOEXEC, 1) = 3
> bind(3, {sa_family=AF_BLUETOOTH,
> sa_data="\0\0\0\0\0U\206\323\0\fm\267&\247"}, 6) = 0
> setsockopt(3, SOL_IP, IP_TTL,
> "\20\0\0\0\377\377\377\377\377\377\377\377\0\0\0\0", 16) = 0
> fstat64(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
> mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0xb771f000
> write(1, "< HCI Command: ogf 0x08, ocf 0x0"..., 44< HCI Command: ogf
> 0x08, ocf 0x000a, plen 1
> ) = 44
> write(1, "  01 \n", 6  01
> )                  = 6
> writev(3, [{"\1", 1}, {"\n \1", 3}, {"\1", 1}], 3) = -1 EPERM (Operation
> not permitted)
> dup(2)                                  = 4
> fcntl64(4, F_GETFL)                     = 0x2 (flags O_RDWR)
> brk(0)                                  = 0x80039000
> brk(0x8005a000)                         = 0x8005a000
> fstat64(4, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
> mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0xb771e000
> write(4, "Send failed: Operation not permi"..., 37Send failed: Operation
> not permitted
> ) = 37