patch-2.1.20 linux/net/lapb/lapb_in.c

• Lines: 800
• Date: Thu Jan 2 15:13:29 1997
• Orig file: v2.1.19/linux/net/lapb/lapb_in.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.1.19/linux/net/lapb/lapb_in.c linux/net/lapb/lapb_in.c
@@ -0,0 +1,799 @@
+/*
+ *	LAPB release 001
+ *
+ *	This is ALPHA test software. This code may break your machine, randomly fail to work with new 
+ *	releases, misbehave and/or generally screw up. It might even work. 
+ *
+ *	This code REQUIRES 2.1.15 or higher/ NET3.038
+ *
+ *	This module:
+ *		This module is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ *	History
+ *	LAPB 001	Jonathan Naulor	Started Coding
+ */
+
+#include <linux/config.h>
+#if defined(CONFIG_LAPB) || defined(CONFIG_LAPB_MODULE)
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <net/lapb.h>
+
+/*
+ *	State machine for state 0, Disconnected State.
+ *	The handling of the timer(s) is in file lapb_timer.c.
+ */
+static void lapb_state0_machine(lapb_cb *lapb, struct sk_buff *skb, int frametype, int pf)
+{
+	switch (frametype) {
+		case LAPB_SABM:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S0 RX SABM(%d)\n", lapb->token, pf);
+#endif
+			if (lapb->mode & LAPB_EXTENDED) {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S0 TX DM(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			} else {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n", lapb->token, pf);
+#endif
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S0 -> S3\n", lapb->token);
+#endif
+				lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+				lapb->state     = LAPB_STATE_3;
+				lapb->condition = 0x00;
+				lapb->t1timer   = 0;
+				lapb->t2timer   = 0;
+				lapb->n2count   = 0;
+				lapb->vs        = 0;
+				lapb->vr        = 0;
+				lapb->va        = 0;
+				lapb_connect_indication(lapb, LAPB_OK);
+			}
+			break;
+
+		case LAPB_SABME:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S0 RX SABME(%d)\n", lapb->token, pf);
+#endif
+			if (lapb->mode & LAPB_EXTENDED) {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n", lapb->token, pf);
+#endif
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S0 -> S3\n", lapb->token);
+#endif
+				lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+				lapb->state     = LAPB_STATE_3;
+				lapb->condition = 0x00;
+				lapb->t1timer   = 0;
+				lapb->t2timer   = 0;
+				lapb->n2count   = 0;
+				lapb->vs        = 0;
+				lapb->vr        = 0;
+				lapb->va        = 0;
+				lapb_connect_indication(lapb, LAPB_OK);
+			} else {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S0 TX DM(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			}
+			break;
+
+		case LAPB_DISC:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S0 RX DISC(%d)\n", lapb->token, pf);
+			printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n", lapb->token, pf);
+#endif
+			lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+			break;
+
+		default:
+			break;
+	}
+
+	kfree_skb(skb, FREE_READ);
+}
+
+/*
+ *	State machine for state 1, Awaiting Connection State.
+ *	The handling of the timer(s) is in file lapb_timer.c.
+ */
+static void lapb_state1_machine(lapb_cb *lapb, struct sk_buff *skb, int frametype, int pf)
+{
+	switch (frametype) {
+		case LAPB_SABM:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S1 RX SABM(%d)\n", lapb->token, pf);
+#endif
+			if (lapb->mode & LAPB_EXTENDED) {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			} else {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S1 TX UA(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+			}
+			break;
+
+		case LAPB_SABME:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S1 RX SABME(%d)\n", lapb->token, pf);
+#endif
+			if (lapb->mode & LAPB_EXTENDED) {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S1 TX UA(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+			} else {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			}
+			break;
+
+		case LAPB_DISC:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S1 RX DISC(%d)\n", lapb->token, pf);
+			printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n", lapb->token, pf);
+#endif
+			lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			break;
+
+		case LAPB_UA:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S1 RX UA(%d)\n", lapb->token, pf);
+#endif
+			if (pf) {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S1 -> S3\n", lapb->token);
+#endif
+				lapb->state     = LAPB_STATE_3;
+				lapb->condition = 0x00;
+				lapb->t1timer   = 0;
+				lapb->t2timer   = 0;
+				lapb->n2count   = 0;
+				lapb->vs        = 0;
+				lapb->vr        = 0;
+				lapb->va        = 0;
+				lapb_connect_confirmation(lapb, LAPB_OK);
+			}
+			break;
+
+		case LAPB_DM:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S1 RX DM(%d)\n", lapb->token, pf);
+#endif
+			if (pf) {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->token);
+#endif
+				lapb_clear_queues(lapb);
+				lapb->state   = LAPB_STATE_0;
+				lapb->t1timer = (lapb->mode & LAPB_DCE) ? lapb->t1 : 0;
+				lapb->t2timer = 0;
+				lapb_disconnect_indication(lapb, LAPB_REFUSED);
+			}
+			break;
+
+		default:
+			break;
+	}
+
+	kfree_skb(skb, FREE_READ);
+}
+
+/*
+ *	State machine for state 2, Awaiting Release State.
+ *	The handling of the timer(s) is in file lapb_timer.c
+ */
+static void lapb_state2_machine(lapb_cb *lapb, struct sk_buff *skb, int frametype, int pf)
+{
+	switch (frametype) {
+		case LAPB_SABM:
+		case LAPB_SABME:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S2 RX {SABM,SABME}(%d)\n", lapb->token, pf);
+			printk(KERN_DEBUG "lapb: (%p) S2 TX DM(%d)\n", lapb->token, pf);
+#endif
+			lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			break;
+
+		case LAPB_DISC:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S2 RX DISC(%d)\n", lapb->token, pf);
+			printk(KERN_DEBUG "lapb: (%p) S2 TX UA(%d)\n", lapb->token, pf);
+#endif
+			lapb_send_control(lapb, LAPB_UA, pf, C_RESPONSE);
+			break;
+
+		case LAPB_UA:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S2 RX UA(%d)\n", lapb->token, pf);
+#endif
+			if (pf) {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S2 -> S0\n", lapb->token);
+#endif
+				lapb->state   = LAPB_STATE_0;
+				lapb->t1timer = (lapb->mode & LAPB_DCE) ? lapb->t1 : 0;
+				lapb->t2timer = 0;
+				lapb_disconnect_confirmation(lapb, LAPB_OK);
+			}
+			break;
+
+		case LAPB_DM:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S2 RX DM(%d)\n", lapb->token, pf);
+#endif
+			if (pf) {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S2 -> S0\n", lapb->token);
+#endif
+				lapb->state   = LAPB_STATE_0;
+				lapb->t1timer = (lapb->mode & LAPB_DCE) ? lapb->t1 : 0;
+				lapb->t2timer = 0;
+				lapb_disconnect_confirmation(lapb, LAPB_NOTCONNECTED);
+			}
+			break;
+
+		case LAPB_I:
+		case LAPB_REJ:
+		case LAPB_RNR:
+		case LAPB_RR:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S2 RX {I,REJ,RNR,RR}(%d)\n", lapb->token, pf);
+			printk(KERN_DEBUG "lapb: (%p) S2 RX DM(%d)\n", lapb->token, pf);
+#endif
+			if (pf) lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			break;
+				
+		default:
+			break;
+	}
+
+	kfree_skb(skb, FREE_READ);
+}
+
+/*
+ *	State machine for state 3, Connected State.
+ *	The handling of the timer(s) is in file lapb_timer.c
+ */
+static void lapb_state3_machine(lapb_cb *lapb, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type)
+{
+	int queued = 0;
+	int modulus;
+	
+	modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
+
+	switch (frametype) {
+		case LAPB_SABM:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX SABM(%d)\n", lapb->token, pf);
+#endif
+			if (lapb->mode & LAPB_EXTENDED) {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S3 TX DM(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			} else {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S3 TX UA(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+				lapb->condition = 0x00;
+				lapb->t1timer   = 0;
+				lapb->t2timer   = 0;
+				lapb->vs        = 0;
+				lapb->vr        = 0;
+				lapb->va        = 0;
+			}
+			break;
+
+		case LAPB_SABME:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX SABME(%d)\n", lapb->token, pf);
+#endif
+			if (lapb->mode & LAPB_EXTENDED) {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S3 TX UA(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+				lapb->condition = 0x00;
+				lapb->t1timer   = 0;
+				lapb->t2timer   = 0;
+				lapb->vs        = 0;
+				lapb->vr        = 0;
+				lapb->va        = 0;
+			} else {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S3 TX DM(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			}
+			break;
+
+		case LAPB_DISC:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX DISC(%d)\n", lapb->token, pf);
+#endif
+#if LAPB_DEBUG > 0
+			printk(KERN_DEBUG "lapb: (%p) S3 -> S0\n", lapb->token);
+#endif
+			lapb_clear_queues(lapb);
+			lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+			lapb->state   = LAPB_STATE_0;
+			lapb->t1timer = (lapb->mode & LAPB_DCE) ? lapb->t1 : 0;
+			lapb->t2timer = 0;
+			lapb_disconnect_indication(lapb, LAPB_OK);
+			break;
+
+		case LAPB_DM:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX DM(%d)\n", lapb->token, pf);
+#endif
+#if LAPB_DEBUG > 0
+			printk(KERN_DEBUG "lapb: (%p) S3 -> S0\n", lapb->token);
+#endif
+			lapb_clear_queues(lapb);
+			lapb->state   = LAPB_STATE_0;
+			lapb->t1timer = (lapb->mode & LAPB_DCE) ? lapb->t1 : 0;
+			lapb->t2timer = 0;
+			lapb_disconnect_indication(lapb, LAPB_NOTCONNECTED);
+			break;
+
+		case LAPB_RNR:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX RNR(%d) R%d\n", lapb->token, pf, nr);
+#endif
+			lapb->condition |= LAPB_PEER_RX_BUSY_CONDITION;
+			lapb_check_need_response(lapb, type, pf);
+			if (lapb_validate_nr(lapb, nr)) {
+				lapb_check_iframes_acked(lapb, nr);
+			} else {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S3 -> S1\n", lapb->token);
+#endif
+				lapb_nr_error_recovery(lapb);
+				lapb->state = LAPB_STATE_1;
+			}
+			break;
+			
+		case LAPB_RR:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX RR(%d) R%d\n", lapb->token, pf, nr);
+#endif
+			lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
+			lapb_check_need_response(lapb, type, pf);
+			if (lapb_validate_nr(lapb, nr)) {
+				lapb_check_iframes_acked(lapb, nr);
+			} else {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S3 -> S1\n", lapb->token);
+#endif
+				lapb_nr_error_recovery(lapb);
+				lapb->state = LAPB_STATE_1;
+			}
+			break;
+				
+		case LAPB_REJ:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX REJ(%d) R%d\n", lapb->token, pf, nr);
+#endif
+			lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
+			lapb_check_need_response(lapb, type, pf);
+			if (lapb_validate_nr(lapb, nr)) {
+				lapb_frames_acked(lapb, nr);
+				lapb->t1timer = 0;
+				lapb_requeue_frames(lapb);
+			} else {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S3 -> S1\n", lapb->token);
+#endif
+				lapb_nr_error_recovery(lapb);
+				lapb->state = LAPB_STATE_1;
+			}
+			break;
+			
+		case LAPB_I:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX I(%d) S%d R%d\n", lapb->token, pf, ns, nr);
+#endif
+			if (type != LAPB_COMMAND)
+				break;
+			if (!lapb_validate_nr(lapb, nr)) {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S3 -> S1\n", lapb->token);
+#endif
+				lapb_nr_error_recovery(lapb);
+				lapb->state = LAPB_STATE_1;
+				break;
+			}
+			if (lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) {
+				lapb_frames_acked(lapb, nr);
+			} else {
+				lapb_check_iframes_acked(lapb, nr);
+			}
+			if (ns == lapb->vr) {
+				lapb->vr = (lapb->vr + 1) % modulus;
+				queued = lapb_data_indication(lapb, skb);
+				lapb->condition &= ~LAPB_REJECT_CONDITION;
+				if (pf) {
+					lapb_enquiry_response(lapb);
+				} else {
+					if (!(lapb->condition & LAPB_ACK_PENDING_CONDITION)) {
+						lapb->t2timer = lapb->t2;
+						lapb->condition |= LAPB_ACK_PENDING_CONDITION;
+					}
+				}
+			} else {
+				if (lapb->condition & LAPB_REJECT_CONDITION) {
+					if (pf)
+						lapb_enquiry_response(lapb);
+				} else {
+#if LAPB_DEBUG > 1
+					printk(KERN_DEBUG "lapb: (%p) S3 TX REJ(%d) R%d\n", lapb->token, pf, lapb->vr);
+#endif
+					lapb->condition |= LAPB_REJECT_CONDITION;
+					lapb_send_control(lapb, LAPB_REJ, pf, LAPB_RESPONSE);
+					lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
+				}
+			}
+			break;
+
+		case LAPB_FRMR:
+		case LAPB_ILLEGAL:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S3 RX {FRMR,ILLEGAL}(%d)\n", lapb->token, pf);
+#endif
+#if LAPB_DEBUG > 0
+			printk(KERN_DEBUG "lapb: (%p) S3 -> S1\n", lapb->token);
+#endif
+			lapb_establish_data_link(lapb);
+			lapb->state = LAPB_STATE_1;
+			break;
+
+		default:
+			break;
+	}
+
+	if (!queued)
+		kfree_skb(skb, FREE_READ);
+}
+
+/*
+ *	State machine for state 4, Timer Recovery State.
+ *	The handling of the timer(s) is in file lapb_timer.c
+ */
+static void lapb_state4_machine(lapb_cb *lapb, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type)
+{
+	int queued = 0;
+	int modulus;
+
+	modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
+
+	switch (frametype) {
+		case LAPB_SABM:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 RX SABM(%d)\n", lapb->token, pf);
+#endif
+			if (lapb->mode & LAPB_EXTENDED) {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S4 TX DM(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			} else {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S4 TX UA(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+				lapb->condition = 0x00;
+				lapb->t1timer   = 0;
+				lapb->t2timer   = 0;
+				lapb->vs        = 0;
+				lapb->vr        = 0;
+				lapb->va        = 0;
+			}
+			break;
+
+		case LAPB_SABME:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 RX SABME(%d)\n", lapb->token, pf);
+#endif
+			if (lapb->mode & LAPB_EXTENDED) {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S4 TX UA(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+				lapb->condition = 0x00;
+				lapb->t1timer   = 0;
+				lapb->t2timer   = 0;
+				lapb->vs        = 0;
+				lapb->vr        = 0;
+				lapb->va        = 0;
+			} else {
+#if LAPB_DEBUG > 1
+				printk(KERN_DEBUG "lapb: (%p) S4 TX DM(%d)\n", lapb->token, pf);
+#endif
+				lapb_send_control(lapb, LAPB_DM, pf, LAPB_RESPONSE);
+			}
+			break;
+
+		case LAPB_DISC:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 RX DISC(%d)\n", lapb->token, pf);
+#endif
+#if LAPB_DEBUG > 0
+			printk(KERN_DEBUG "lapb: (%p) S4 -> S0\n", lapb->token);
+#endif
+			lapb_clear_queues(lapb);
+			lapb_send_control(lapb, LAPB_UA, pf, LAPB_RESPONSE);
+			lapb->state   = LAPB_STATE_0;
+			lapb->t1timer = (lapb->mode & LAPB_DCE) ? lapb->t1 : 0;
+			lapb->t2timer = 0;
+			lapb_disconnect_indication(lapb, LAPB_OK);
+			break;
+
+		case LAPB_DM:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 RX DM(%d)\n", lapb->token, pf);
+#endif
+#if LAPB_DEBUG > 0
+			printk(KERN_DEBUG "lapb: (%p) S4 -> S0\n", lapb->token);
+#endif
+			lapb_clear_queues(lapb);
+			lapb->state   = LAPB_STATE_0;
+			lapb->t1timer = (lapb->mode & LAPB_DCE) ? lapb->t1 : 0;
+			lapb->t2timer = 0;
+			lapb_disconnect_indication(lapb, LAPB_NOTCONNECTED);
+			break;
+
+		case LAPB_RNR:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 RX RNR(%d) R%d\n", lapb->token, pf, nr);
+#endif
+			lapb->condition |= LAPB_PEER_RX_BUSY_CONDITION;
+			if (type == LAPB_RESPONSE && pf) {
+				lapb->t1timer = 0;
+				if (lapb_validate_nr(lapb, nr)) {
+					lapb_frames_acked(lapb, nr);
+					if (lapb->vs == lapb->va) {
+#if LAPB_DEBUG > 0
+						printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n", lapb->token);
+#endif
+						lapb->n2count = 0;
+						lapb->state   = LAPB_STATE_3;
+					}
+				} else {
+#if LAPB_DEBUG > 0
+					printk(KERN_DEBUG "lapb: (%p) S4 -> S1\n", lapb->token);
+#endif
+					lapb_nr_error_recovery(lapb);
+					lapb->state = LAPB_STATE_1;
+				}
+				break;
+			}
+			 
+			lapb_check_need_response(lapb, type, pf);
+			if (lapb_validate_nr(lapb, nr)) {
+				lapb_frames_acked(lapb, nr);
+			} else {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S4 -> S1\n", lapb->token);
+#endif
+				lapb_nr_error_recovery(lapb);
+				lapb->state = LAPB_STATE_1;
+			}
+			break;
+			
+		case LAPB_RR:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 RX RR(%d) R%d\n", lapb->token, pf, nr);
+#endif
+			lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
+			if (pf && type == LAPB_RESPONSE) {
+				lapb->t1timer = 0;
+				if (lapb_validate_nr(lapb, nr)) {
+					lapb_frames_acked(lapb, nr);
+					if (lapb->vs == lapb->va) {
+#if LAPB_DEBUG > 0
+						printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n", lapb->token);
+#endif
+						lapb->n2count = 0;
+						lapb->state   = LAPB_STATE_3;
+					} else {
+						lapb_requeue_frames(lapb);
+					}
+				} else {
+#if LAPB_DEBUG > 0
+					printk(KERN_DEBUG "lapb: (%p) S4 -> S1\n", lapb->token);
+#endif
+					lapb_nr_error_recovery(lapb);
+					lapb->state = LAPB_STATE_1;
+				}
+				break;
+			}
+
+			lapb_check_need_response(lapb, type, pf);
+			if (lapb_validate_nr(lapb, nr)) {
+				lapb_frames_acked(lapb, nr);
+			} else {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S4 -> S1\n", lapb->token);
+#endif
+				lapb_nr_error_recovery(lapb);
+				lapb->state = LAPB_STATE_1;
+			}
+			break;
+
+		case LAPB_REJ:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 RX REJ(%d) R%d\n", lapb->token, pf, nr);
+#endif
+			lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
+			if (pf && type == LAPB_RESPONSE) {
+				lapb->t1timer = 0;
+				if (lapb_validate_nr(lapb, nr)) {
+					lapb_frames_acked(lapb, nr);
+					if (lapb->vs == lapb->va) {
+#if LAPB_DEBUG > 0
+						printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n", lapb->token);
+#endif
+						lapb->n2count = 0;
+						lapb->state   = LAPB_STATE_3;
+					} else {
+						lapb_requeue_frames(lapb);
+					}
+				} else {
+#if LAPB_DEBUG > 0
+					printk(KERN_DEBUG "lapb: (%p) S4 -> S1\n", lapb->token);
+#endif
+					lapb_nr_error_recovery(lapb);
+					lapb->state = LAPB_STATE_1;
+				}
+				break;
+			}
+			
+			lapb_check_need_response(lapb, type, pf);	
+			if (lapb_validate_nr(lapb, nr)) {
+				lapb_frames_acked(lapb, nr);
+				if (lapb->vs != lapb->va)
+					lapb_requeue_frames(lapb);
+			} else {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S4 -> S1\n", lapb->token);
+#endif
+				lapb_nr_error_recovery(lapb);
+				lapb->state = LAPB_STATE_1;
+			}
+			break;
+
+		case LAPB_I:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 RX I(%d) S%d R%d\n", lapb->token, pf, ns, nr);
+#endif
+			if (type != LAPB_COMMAND)
+				break;
+			if (!lapb_validate_nr(lapb, nr)) {
+#if LAPB_DEBUG > 0
+				printk(KERN_DEBUG "lapb: (%p) S4 -> S1\n", lapb->token);
+#endif
+				lapb_nr_error_recovery(lapb);
+				lapb->state = LAPB_STATE_1;
+				break;
+			}
+			lapb_frames_acked(lapb, nr);
+			if (ns == lapb->vr) {
+				lapb->vr = (lapb->vr + 1) % modulus;
+				queued = lapb_data_indication(lapb, skb);
+				lapb->condition &= ~LAPB_REJECT_CONDITION;
+				if (pf) {
+					lapb_enquiry_response(lapb);
+				} else {
+					if (!(lapb->condition & LAPB_ACK_PENDING_CONDITION)) {
+						lapb->t2timer = lapb->t2;
+						lapb->condition |= LAPB_ACK_PENDING_CONDITION;
+					}
+				}
+			} else {
+				if (lapb->condition & LAPB_REJECT_CONDITION) {
+					if (pf)
+						lapb_enquiry_response(lapb);
+				} else {
+#if LAPB_DEBUG > 1
+					printk(KERN_DEBUG "lapb: (%p) S4 TX REJ(%d) R%d\n", lapb->token, pf, lapb->vr);
+#endif
+					lapb->condition |= LAPB_REJECT_CONDITION;
+					lapb_send_control(lapb, LAPB_REJ, pf, LAPB_RESPONSE);
+					lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
+				}
+			}
+			break;
+		
+		case LAPB_FRMR:
+		case LAPB_ILLEGAL:
+#if LAPB_DEBUG > 1
+			printk(KERN_DEBUG "lapb: (%p) S4 TX {FRMR,ILLEGAL}(%d)\n", lapb->token, pf);
+#endif
+#if LAPB_DEBUG > 0
+			printk(KERN_DEBUG "lapb: (%p) S4 -> S1\n", lapb->token);
+#endif
+			lapb_establish_data_link(lapb);
+			lapb->state = LAPB_STATE_1;
+			break;
+
+		default:
+			break;
+	}
+
+	if (!queued)
+		kfree_skb(skb, FREE_READ);
+}
+
+/*
+ *	Process an incoming LAPB frame
+ */
+int lapb_data_received(void *token, struct sk_buff *skb)
+{
+	int frametype, ns, nr, pf, type;
+	lapb_cb *lapb;
+	
+	if ((lapb = lapb_tokentostruct(token)) == NULL)
+		return LAPB_BADTOKEN;
+
+	del_timer(&lapb->timer);
+
+	frametype = lapb_decode(lapb, skb, &ns, &nr, &pf, &type);
+
+	switch (lapb->state) {
+		case LAPB_STATE_0:
+			lapb_state0_machine(lapb, skb, frametype, pf);
+			break;
+		case LAPB_STATE_1:
+			lapb_state1_machine(lapb, skb, frametype, pf);
+			break;
+		case LAPB_STATE_2:
+			lapb_state2_machine(lapb, skb, frametype, pf);
+			break;
+		case LAPB_STATE_3:
+			lapb_state3_machine(lapb, skb, frametype, ns, nr, pf, type);
+			break;
+		case LAPB_STATE_4:
+			lapb_state4_machine(lapb, skb, frametype, ns, nr, pf, type);
+			break;
+	}
+
+	lapb_set_timer(lapb);
+
+	return LAPB_OK;
+}
+
+#endif