On Wed, May 20, 2009 at 2:57 PM, Nick Pelly<npelly@xxxxxxxxxx> wrote:
> On Tue, May 19, 2009 at 7:49 PM, Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote:
>> Hi Nick,
>>
>>> I found that neither close() nor shutdown() on a RFCOMM socket that is
>>> currently connecting will cause the kernel to send HCI Create
>>> Connection Cancel Command. This seems like a problem, since this means
>>> there is no way to cancel an outgoing connection - even in the single
>>> threaded case.
>>>
>>> Ideally for our use case both shutdown() and close() would cause the
>>> Create Connection Cancel command to be sent.
>>>
>>> It is easy to check this with a code snippet like:
>>>
>>> fd = _socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
>>> flags = fcntl(fd, F_GETFL);
>>> fcntl(fd, F_SETFL, flags | O_NONBLOCK);
>>> connect(fd, (struct sockaddr *) &addr, sizeof(struct sockaddr));
>>>
>>> sleep(1);
>>> shutdown(fd, SHUT_RDWR);
>>> sleep(1);
>>> close(fd);
>>>
>>> Following this with hcidump you can see the Create Connection command
>>> sent, but it does not get canceled on close or shutdown.
>>>
>>> 2009-05-19 17:55:16.098103 < HCI Command: Create Connection
>>> (0x01|0x0005) plen 13
>>> bdaddr 00:11:22:33:44:55 ptype 0xcc18 rswitch 0x01 clkoffset 0x0000
>>> Packet type: DM1 DM3 DM5 DH1 DH3 DH5
>>> 2009-05-19 17:55:16.118305 > HCI Event: Command Status (0x0f) plen 4
>>> Create Connection (0x01|0x0005) status 0x00 ncmd 1
>>>
>>> <--- shutdown()
>>> <--- close()
>>>
>>> 2009-05-19 17:55:26.361744 > HCI Event: Connect Complete (0x03) plen 11
>>> status 0x04 handle 1 bdaddr 00:11:22:33:44:55 type ACL encrypt 0x00
>>> Error: Page Timeout
>>> 2009-05-19 17:55:33.119251 < HCI Command: Create Connection
>>> (0x01|0x0005) plen 13
>>> bdaddr 00:11:22:33:44:55 ptype 0xcc18 rswitch 0x01 clkoffset 0x0000
>>> Packet type: DM1 DM3 DM5 DH1 DH3 DH5
>>> 2009-05-19 17:55:33.139240 > HCI Event: Command Status (0x0f) plen 4
>>> Create Connection (0x01|0x0005) status 0x00 ncmd 1
>>>
>>>
>>> Tested on 2.6.29.
>>>
>>> Is this behavior intentional or is this a bug?
>>
>> I know that I tested this massively with non-blocking sockets and there
>> is works perfectly fine. No idea why shutdown() or close() is not
>> catching this.
>>
>> Please check with 2.6.30-rc6 kernel since the Simple Pairing changes
>> might have broken something here.
>
> I tested on the following kernels:
>
> Android 2.6.27 (2.6.27 + several bluetooth-next.git patches)
> Android 2.6.29 (2.6.29 + several bluetooth-next.git patches)
> 2.6.28 (Ubuntu 9.10)
>
> All with the same results.
>
> I don't have easy access to a 2.6.30 kernel right now.
>
> Thanks for letting us know this is not intentional behavior.
FYI: I still see this issue on 2.6.31-rc1
Any suggestions of where to begin debugging this? I will look at it today.
$ uname -a
Linux npelly-kernel 2.6.31-020631rc1gc0d1117-generic
#020631rc1gc0d1117 SMP Wed Jul 1 09:04:38 UTC 2009 i686 GNU/Linux
$ hcidump -XVt
2009-07-06 11:46:53.792864 < HCI Command: Create Connection
(0x01|0x0005) plen 13
bdaddr 00:01:02:0A:0B:0C ptype 0xcc18 rswitch 0x01 clkoffset 0x0000
Packet type: DM1 DM3 DM5 DH1 DH3 DH5
2009-07-06 11:46:53.800563 > HCI Event: Command Status (0x0f) plen 4
Create Connection (0x01|0x0005) status 0x00 ncmd 1
2009-07-06 11:46:58.923825 > HCI Event: Connect Complete (0x03) plen 11
status 0x04 handle 0 bdaddr 00:01:02:0A:0B:0C type ACL encrypt 0x00
Error: Page Timeout
$ strace ./a.out
[...]
socket(PF_BLUETOOTH, SOCK_STREAM, 3) = 3
fcntl64(3, F_GETFL) = 0x2 (flags O_RDWR)
fcntl64(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
connect(3, {sa_family=AF_BLUETOOTH,
sa_data="\f\v\n\2\1\0\4\10\2\0\0\0\t\207"...}, 10) = -1 EINPROGRESS
(Operation now in progress)
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({1, 0}, {1, 0}) = 0
shutdown(3, 2 /* send and receive */) = 0
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({1, 0}, {1, 0}) = 0
close(3) = 0
exit_group(0) = ?
$ cat sock_shutdown_bug.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <fcntl.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/rfcomm.h>
int main(int argc, char **argv) {
int fd;
int ret;
long flags;
struct sockaddr_rc addr;
addr.rc_family = AF_BLUETOOTH;
str2ba("00:01:02:0A:0B:0C", &addr.rc_bdaddr);
addr.rc_channel = 4;
fd = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
flags = fcntl(fd, F_GETFL);
fcntl(fd, F_SETFL, flags | O_NONBLOCK);
connect(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_rc));
sleep(1);
shutdown(fd, SHUT_RDWR);
sleep(1);
close(fd);
}
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