EBADFD on RFComm connect

EBADFD on RFComm connect

[Stephen Crane]

[-- Attachment #1: Type: text/plain, Size: 575 bytes --]

Hi Max, Marcel,
Under what circumstances can connect() return EBADFD?

I have a couple of programs (attached) one of which opens a listening
socket and accepts 32 connections. The other loops attempting 32
connections to the same channel. On the second connection connect()
always fails with EBADFD. (If I leave in the 0.5 second delay it all
works fine.)

I've also attached hcidumps from each machine --- each is running kernel
2.4.21-mh2.

Thanks,
Steve
-- 
Stephen Crane, Rococo Software Ltd. http://www.rococosoft.com
steve.crane@rococosoft.com +353-1-6601315 (ext 209)

[-- Attachment #2: connector.c --]
[-- Type: text/x-c, Size: 678 bytes --]

#include <sys/socket.h>
#include <netinet/in.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/rfcomm.h>
#include <unistd.h>
#include <errno.h>

int main(int argc, char *argv[])
{
	struct sockaddr_rc addr;
	int addr_len = sizeof(addr);
	int i;

	addr.rc_channel = 2;
	addr.rc_family = AF_BLUETOOTH;
	baswap(&addr.rc_bdaddr, strtoba(argv[1]));
	for (i = 0; i < 32; i++) {
		int s = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
		char c;
		while (0 > connect(s, (struct sockaddr *)&addr, sizeof(addr)))
			if (errno != EBUSY) {
				perror("connect");
				return -1;
			}
		printf("connected %d\n", i);
		read(s, &c, 1);
		close(s);
//		usleep(500000);
	}
	return 0;
}

[-- Attachment #3: listener.c --]
[-- Type: text/x-c, Size: 914 bytes --]

#include <unistd.h>
#include <malloc.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/rfcomm.h>

int main(int argc, char *argv[])
{
	int l = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
	struct sockaddr_rc addr, myaddr;
	int i, addr_len = sizeof(addr);

	if (0 > l) {
		perror("socket");
		return -1;
	}
	memset(&addr, 0, sizeof(addr));
	addr.rc_family = AF_BLUETOOTH;
	addr.rc_channel = 2;
	bacpy(&addr.rc_bdaddr, BDADDR_ANY); 
	if (0 > bind(l, (struct sockaddr *)&addr, sizeof(addr))) { 
		perror("bind");
		return -1;
	}
	if (0 > listen(l, 10)) {
		perror("listen");
		return -1;
	}
	for (i=0; i < 32; i++) {
		int s = accept(l, (struct sockaddr *)&addr, &addr_len);
		char c;
		if (0 > s) {
			perror("accept");
			return -1;
		}
		printf("accepted %d\n", i);
		write(s, &c, 1);
		close(s);
	}
	return 0;
}

[-- Attachment #4: connect --]
[-- Type: application/octet-stream, Size: 1254 bytes --]

[-- Attachment #5: listen --]
[-- Type: application/octet-stream, Size: 1274 bytes --]

Re: [Bluez-devel] EBADFD on RFComm connect

[Max Krasnyansky]

At 06:29 AM 7/22/2003, Stephen Crane wrote:
>Hi Max, Marcel,
>Under what circumstances can connect() return EBADFD?
>
>I have a couple of programs (attached) one of which opens a listening
>socket and accepts 32 connections. The other loops attempting 32
>connections to the same channel. On the second connection connect()
>always fails with EBADFD. (If I leave in the 0.5 second delay it all
>works fine.)

You can not do this
        while (0 > connect(s, (struct sockaddr *)&addr, sizeof(addr)))
               if (errno != EBUSY) {
                   perror("connect");
                   return -1;
               }

If connect returns EBUSY error you have to close() the socket. And it does
indeed return EBUSY in your case (I ran the progs) because close() is asynchronous
and that channel still exist (two connections on the same channel are not allowed 
in RFCOMM). What you can do to avoid that error is to enable SO_LINGER option on that
socket, in which case close() will be synchronous. 

Max
 

Re: [Bluez-devel] EBADFD on RFComm connect

[Stephen Crane]

On Wed, 2003-07-23 at 01:33, Max Krasnyansky wrote:

> You can not do this
>         while (0 > connect(s, (struct sockaddr *)&addr, sizeof(addr)))
>                if (errno != EBUSY) {
>                    perror("connect");
>                    return -1;
>                }
> 
> If connect returns EBUSY error you have to close() the socket. And it does
> indeed return EBUSY in your case (I ran the progs) because close() is asynchronous
> and that channel still exist (two connections on the same channel are not allowed 
> in RFCOMM). What you can do to avoid that error is to enable SO_LINGER option on that
> socket, in which case close() will be synchronous. 

Thanks Max. That's fixed it. Another one for the programming manual?

Steve
-- 
Stephen Crane, Rococo Software Ltd. http://www.rococosoft.com
steve.crane@rococosoft.com +353-1-6601315 (ext 209)

Re: [Bluez-devel] EBADFD on RFComm connect

[Max Krasnyansky]

At 07:09 AM 7/24/2003, Stephen Crane wrote:
>On Wed, 2003-07-23 at 01:33, Max Krasnyansky wrote:
>
>> You can not do this
>>         while (0 > connect(s, (struct sockaddr *)&addr, sizeof(addr)))
>>                if (errno != EBUSY) {
>>                    perror("connect");
>>                    return -1;
>>                }
>> 
>> If connect returns EBUSY error you have to close() the socket. And it does
>> indeed return EBUSY in your case (I ran the progs) because close() is asynchronous
>> and that channel still exist (two connections on the same channel are not allowed 
>> in RFCOMM). What you can do to avoid that error is to enable SO_LINGER option on that
>> socket, in which case close() will be synchronous. 
>
>Thanks Max. That's fixed it. Another one for the programming manual?
Yep.

Max