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			It is unclear if net/lapb code is supposed to be ready for 8021q.
We can at least avoid crashes like the following :
skbuff: skb_under_panic: text:ffffffff8aabe1f6 len:24 put:20 head:ffff88802824a400 data:ffff88802824a3fe tail:0x16 end:0x140 dev:nr0.2
------------[ cut here ]------------
 kernel BUG at net/core/skbuff.c:206 !
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 UID: 0 PID: 5508 Comm: dhcpcd Not tainted 6.12.0-rc7-syzkaller-00144-g66418447d27b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
 RIP: 0010:skb_panic net/core/skbuff.c:206 [inline]
 RIP: 0010:skb_under_panic+0x14b/0x150 net/core/skbuff.c:216
Code: 0d 8d 48 c7 c6 2e 9e 29 8e 48 8b 54 24 08 8b 0c 24 44 8b 44 24 04 4d 89 e9 50 41 54 41 57 41 56 e8 1a 6f 37 02 48 83 c4 20 90 <0f> 0b 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3
RSP: 0018:ffffc90002ddf638 EFLAGS: 00010282
RAX: 0000000000000086 RBX: dffffc0000000000 RCX: 7a24750e538ff600
RDX: 0000000000000000 RSI: 0000000000000201 RDI: 0000000000000000
RBP: ffff888034a86650 R08: ffffffff8174b13c R09: 1ffff920005bbe60
R10: dffffc0000000000 R11: fffff520005bbe61 R12: 0000000000000140
R13: ffff88802824a400 R14: ffff88802824a3fe R15: 0000000000000016
FS:  00007f2a5990d740(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2631fd CR3: 0000000029504000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
  skb_push+0xe5/0x100 net/core/skbuff.c:2636
  nr_header+0x36/0x320 net/netrom/nr_dev.c:69
  dev_hard_header include/linux/netdevice.h:3148 [inline]
  vlan_dev_hard_header+0x359/0x480 net/8021q/vlan_dev.c:83
  dev_hard_header include/linux/netdevice.h:3148 [inline]
  lapbeth_data_transmit+0x1f6/0x2a0 drivers/net/wan/lapbether.c:257
  lapb_data_transmit+0x91/0xb0 net/lapb/lapb_iface.c:447
  lapb_transmit_buffer+0x168/0x1f0 net/lapb/lapb_out.c:149
 lapb_establish_data_link+0x84/0xd0
 lapb_device_event+0x4e0/0x670
  notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
 __dev_notify_flags+0x207/0x400
  dev_change_flags+0xf0/0x1a0 net/core/dev.c:8922
  devinet_ioctl+0xa4e/0x1aa0 net/ipv4/devinet.c:1188
  inet_ioctl+0x3d7/0x4f0 net/ipv4/af_inet.c:1003
  sock_do_ioctl+0x158/0x460 net/socket.c:1227
  sock_ioctl+0x626/0x8e0 net/socket.c:1346
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:907 [inline]
  __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+fb99d1b0c0f81d94a5e2@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/67506220.050a0220.17bd51.006c.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241204141031.4030267-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
		
	
			
		
			
				
	
	
		
			162 lines
		
	
	
	
		
			4.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			162 lines
		
	
	
	
		
			4.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* SPDX-License-Identifier: GPL-2.0 */
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| #ifndef _LAPB_H
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| #define _LAPB_H 
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| #include <linux/lapb.h>
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| #include <linux/refcount.h>
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| 
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| #define	LAPB_HEADER_LEN MAX_HEADER		/* LAPB over Ethernet + a bit more */
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| 
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| #define	LAPB_ACK_PENDING_CONDITION	0x01
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| #define	LAPB_REJECT_CONDITION		0x02
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| #define	LAPB_PEER_RX_BUSY_CONDITION	0x04
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| 
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| /* Control field templates */
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| #define	LAPB_I		0x00	/* Information frames */
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| #define	LAPB_S		0x01	/* Supervisory frames */
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| #define	LAPB_U		0x03	/* Unnumbered frames */
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| 
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| #define	LAPB_RR		0x01	/* Receiver ready */
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| #define	LAPB_RNR	0x05	/* Receiver not ready */
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| #define	LAPB_REJ	0x09	/* Reject */
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| 
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| #define	LAPB_SABM	0x2F	/* Set Asynchronous Balanced Mode */
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| #define	LAPB_SABME	0x6F	/* Set Asynchronous Balanced Mode Extended */
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| #define	LAPB_DISC	0x43	/* Disconnect */
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| #define	LAPB_DM		0x0F	/* Disconnected mode */
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| #define	LAPB_UA		0x63	/* Unnumbered acknowledge */
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| #define	LAPB_FRMR	0x87	/* Frame reject */
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| 
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| #define LAPB_ILLEGAL	0x100	/* Impossible to be a real frame type */
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| 
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| #define	LAPB_SPF	0x10	/* Poll/final bit for standard LAPB */
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| #define	LAPB_EPF	0x01	/* Poll/final bit for extended LAPB */
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| 
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| #define	LAPB_FRMR_W	0x01	/* Control field invalid	*/
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| #define	LAPB_FRMR_X	0x02	/* I field invalid		*/
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| #define	LAPB_FRMR_Y	0x04	/* I field too long		*/
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| #define	LAPB_FRMR_Z	0x08	/* Invalid N(R)			*/
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| 
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| #define	LAPB_POLLOFF	0
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| #define	LAPB_POLLON	1
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| 
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| /* LAPB C-bit */
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| #define LAPB_COMMAND	1
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| #define LAPB_RESPONSE	2
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| 
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| #define	LAPB_ADDR_A	0x03
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| #define	LAPB_ADDR_B	0x01
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| #define	LAPB_ADDR_C	0x0F
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| #define	LAPB_ADDR_D	0x07
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| 
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| /* Define Link State constants. */
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| enum {
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| 	LAPB_STATE_0,	/* Disconnected State		*/
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| 	LAPB_STATE_1,	/* Awaiting Connection State	*/
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| 	LAPB_STATE_2,	/* Awaiting Disconnection State	*/
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| 	LAPB_STATE_3,	/* Data Transfer State		*/
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| 	LAPB_STATE_4	/* Frame Reject State		*/
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| };
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| 
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| #define	LAPB_DEFAULT_MODE		(LAPB_STANDARD | LAPB_SLP | LAPB_DTE)
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| #define	LAPB_DEFAULT_WINDOW		7		/* Window=7 */
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| #define	LAPB_DEFAULT_T1			(5 * HZ)	/* T1=5s    */
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| #define	LAPB_DEFAULT_T2			(1 * HZ)	/* T2=1s    */
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| #define	LAPB_DEFAULT_N2			20		/* N2=20    */
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| 
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| #define	LAPB_SMODULUS	8
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| #define	LAPB_EMODULUS	128
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| 
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| /*
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|  *	Information about the current frame.
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|  */
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| struct lapb_frame {
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| 	unsigned short		type;		/* Parsed type		*/
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| 	unsigned short		nr, ns;		/* N(R), N(S)		*/
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| 	unsigned char		cr;		/* Command/Response	*/
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| 	unsigned char		pf;		/* Poll/Final		*/
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| 	unsigned char		control[2];	/* Original control data*/
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| };
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| 
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| /*
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|  *	The per LAPB connection control structure.
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|  */
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| struct lapb_cb {
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| 	struct list_head	node;
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| 	struct net_device	*dev;
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| 
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| 	/* Link status fields */
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| 	unsigned int		mode;
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| 	unsigned char		state;
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| 	unsigned short		vs, vr, va;
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| 	unsigned char		condition;
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| 	unsigned short		n2, n2count;
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| 	unsigned short		t1, t2;
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| 	struct timer_list	t1timer, t2timer;
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| 	bool			t1timer_running, t2timer_running;
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| 
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| 	/* Internal control information */
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| 	struct sk_buff_head	write_queue;
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| 	struct sk_buff_head	ack_queue;
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| 	unsigned char		window;
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| 	const struct lapb_register_struct *callbacks;
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| 
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| 	/* FRMR control information */
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| 	struct lapb_frame	frmr_data;
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| 	unsigned char		frmr_type;
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| 
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| 	spinlock_t		lock;
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| 	refcount_t		refcnt;
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| };
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| 
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| /* lapb_iface.c */
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| void lapb_connect_confirmation(struct lapb_cb *lapb, int);
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| void lapb_connect_indication(struct lapb_cb *lapb, int);
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| void lapb_disconnect_confirmation(struct lapb_cb *lapb, int);
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| void lapb_disconnect_indication(struct lapb_cb *lapb, int);
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| int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *);
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| int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *);
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| 
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| /* lapb_in.c */
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| void lapb_data_input(struct lapb_cb *lapb, struct sk_buff *);
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| 
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| /* lapb_out.c */
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| void lapb_kick(struct lapb_cb *lapb);
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| void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *, int);
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| void lapb_establish_data_link(struct lapb_cb *lapb);
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| void lapb_enquiry_response(struct lapb_cb *lapb);
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| void lapb_timeout_response(struct lapb_cb *lapb);
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| void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short);
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| void lapb_check_need_response(struct lapb_cb *lapb, int, int);
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| 
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| /* lapb_subr.c */
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| void lapb_clear_queues(struct lapb_cb *lapb);
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| void lapb_frames_acked(struct lapb_cb *lapb, unsigned short);
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| void lapb_requeue_frames(struct lapb_cb *lapb);
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| int lapb_validate_nr(struct lapb_cb *lapb, unsigned short);
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| int lapb_decode(struct lapb_cb *lapb, struct sk_buff *, struct lapb_frame *);
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| void lapb_send_control(struct lapb_cb *lapb, int, int, int);
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| void lapb_transmit_frmr(struct lapb_cb *lapb);
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| 
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| /* lapb_timer.c */
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| void lapb_start_t1timer(struct lapb_cb *lapb);
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| void lapb_start_t2timer(struct lapb_cb *lapb);
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| void lapb_stop_t1timer(struct lapb_cb *lapb);
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| void lapb_stop_t2timer(struct lapb_cb *lapb);
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| int lapb_t1timer_running(struct lapb_cb *lapb);
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| 
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| /*
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|  * Debug levels.
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|  *	0 = Off
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|  *	1 = State Changes
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|  *	2 = Packets I/O and State Changes
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|  *	3 = Hex dumps, Packets I/O and State Changes.
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|  */
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| #define	LAPB_DEBUG	0
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| 
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| #define lapb_dbg(level, fmt, ...)			\
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| do {							\
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| 	if (level < LAPB_DEBUG)				\
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| 		pr_debug(fmt, ##__VA_ARGS__);		\
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| } while (0)
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| 
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| #endif
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