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lapb_in.c
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lapb_in.c
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/*
* LAPB release 002
*
* 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
* LAPB 002 Jonathan Naylor New timer architecture.
* 2000-10-29 Henner Eisen lapb_data_indication() return status.
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.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(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
switch (frame->type) {
case LAPB_SABM:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S0 RX SABM(%d)\n",
lapb->dev, frame->pf);
#endif
if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S0 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
} else {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S0 -> S3\n",
lapb->dev);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_3;
lapb->condition = 0x00;
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->dev, frame->pf);
#endif
if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S0 -> S3\n",
lapb->dev);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_3;
lapb->condition = 0x00;
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->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
}
break;
case LAPB_DISC:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S0 RX DISC(%d)\n",
lapb->dev, frame->pf);
printk(KERN_DEBUG "lapb: (%p) S0 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
break;
default:
break;
}
kfree_skb(skb);
}
/*
* 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(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
switch (frame->type) {
case LAPB_SABM:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 RX SABM(%d)\n",
lapb->dev, frame->pf);
#endif
if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
} else {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
}
break;
case LAPB_SABME:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 RX SABME(%d)\n",
lapb->dev, frame->pf);
#endif
if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
} else {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
}
break;
case LAPB_DISC:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 RX DISC(%d)\n",
lapb->dev, frame->pf);
printk(KERN_DEBUG "lapb: (%p) S1 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
break;
case LAPB_UA:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 RX UA(%d)\n",
lapb->dev, frame->pf);
#endif
if (frame->pf) {
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S1 -> S3\n",
lapb->dev);
#endif
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_3;
lapb->condition = 0x00;
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->dev, frame->pf);
#endif
if (frame->pf) {
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n",
lapb->dev);
#endif
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb_disconnect_indication(lapb, LAPB_REFUSED);
}
break;
}
kfree_skb(skb);
}
/*
* 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(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
switch (frame->type) {
case LAPB_SABM:
case LAPB_SABME:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S2 RX {SABM,SABME}(%d)\n",
lapb->dev, frame->pf);
printk(KERN_DEBUG "lapb: (%p) S2 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
break;
case LAPB_DISC:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S2 RX DISC(%d)\n",
lapb->dev, frame->pf);
printk(KERN_DEBUG "lapb: (%p) S2 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
break;
case LAPB_UA:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S2 RX UA(%d)\n",
lapb->dev, frame->pf);
#endif
if (frame->pf) {
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S2 -> S0\n",
lapb->dev);
#endif
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
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->dev, frame->pf);
#endif
if (frame->pf) {
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S2 -> S0\n",
lapb->dev);
#endif
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
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->dev, frame->pf);
printk(KERN_DEBUG "lapb: (%p) S2 RX DM(%d)\n",
lapb->dev, frame->pf);
#endif
if (frame->pf)
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
break;
}
kfree_skb(skb);
}
/*
* State machine for state 3, Connected State.
* The handling of the timer(s) is in file lapb_timer.c
*/
static void lapb_state3_machine(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
int queued = 0;
int modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS :
LAPB_SMODULUS;
switch (frame->type) {
case LAPB_SABM:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 RX SABM(%d)\n",
lapb->dev, frame->pf);
#endif
if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
} else {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->condition = 0x00;
lapb->n2count = 0;
lapb->vs = 0;
lapb->vr = 0;
lapb->va = 0;
lapb_requeue_frames(lapb);
}
break;
case LAPB_SABME:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 RX SABME(%d)\n",
lapb->dev, frame->pf);
#endif
if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->condition = 0x00;
lapb->n2count = 0;
lapb->vs = 0;
lapb->vr = 0;
lapb->va = 0;
lapb_requeue_frames(lapb);
} else {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
}
break;
case LAPB_DISC:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 RX DISC(%d)\n",
lapb->dev, frame->pf);
#endif
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S0\n",
lapb->dev);
#endif
lapb_clear_queues(lapb);
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_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->dev, frame->pf);
#endif
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S0\n",
lapb->dev);
#endif
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
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->dev, frame->pf, frame->nr);
#endif
lapb->condition |= LAPB_PEER_RX_BUSY_CONDITION;
lapb_check_need_response(lapb, frame->cr, frame->pf);
if (lapb_validate_nr(lapb, frame->nr)) {
lapb_check_iframes_acked(lapb, frame->nr);
} else {
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_Z;
lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n",
lapb->dev);
#endif
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
}
break;
case LAPB_RR:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 RX RR(%d) R%d\n",
lapb->dev, frame->pf, frame->nr);
#endif
lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
lapb_check_need_response(lapb, frame->cr, frame->pf);
if (lapb_validate_nr(lapb, frame->nr)) {
lapb_check_iframes_acked(lapb, frame->nr);
} else {
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_Z;
lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n",
lapb->dev);
#endif
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
}
break;
case LAPB_REJ:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 RX REJ(%d) R%d\n",
lapb->dev, frame->pf, frame->nr);
#endif
lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
lapb_check_need_response(lapb, frame->cr, frame->pf);
if (lapb_validate_nr(lapb, frame->nr)) {
lapb_frames_acked(lapb, frame->nr);
lapb_stop_t1timer(lapb);
lapb->n2count = 0;
lapb_requeue_frames(lapb);
} else {
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_Z;
lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n",
lapb->dev);
#endif
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
}
break;
case LAPB_I:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 RX I(%d) S%d R%d\n",
lapb->dev, frame->pf, frame->ns, frame->nr);
#endif
if (!lapb_validate_nr(lapb, frame->nr)) {
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_Z;
lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n",
lapb->dev);
#endif
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
break;
}
if (lapb->condition & LAPB_PEER_RX_BUSY_CONDITION)
lapb_frames_acked(lapb, frame->nr);
else
lapb_check_iframes_acked(lapb, frame->nr);
if (frame->ns == lapb->vr) {
int cn;
cn = lapb_data_indication(lapb, skb);
queued = 1;
/*
* If upper layer has dropped the frame, we
* basically ignore any further protocol
* processing. This will cause the peer
* to re-transmit the frame later like
* a frame lost on the wire.
*/
if (cn == NET_RX_DROP) {
printk(KERN_DEBUG
"LAPB: rx congestion\n");
break;
}
lapb->vr = (lapb->vr + 1) % modulus;
lapb->condition &= ~LAPB_REJECT_CONDITION;
if (frame->pf)
lapb_enquiry_response(lapb);
else {
if (!(lapb->condition &
LAPB_ACK_PENDING_CONDITION)) {
lapb->condition |= LAPB_ACK_PENDING_CONDITION;
lapb_start_t2timer(lapb);
}
}
} else {
if (lapb->condition & LAPB_REJECT_CONDITION) {
if (frame->pf)
lapb_enquiry_response(lapb);
} else {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG
"lapb: (%p) S3 TX REJ(%d) R%d\n",
lapb->dev, frame->pf, lapb->vr);
#endif
lapb->condition |= LAPB_REJECT_CONDITION;
lapb_send_control(lapb, LAPB_REJ,
frame->pf,
LAPB_RESPONSE);
lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
}
}
break;
case LAPB_FRMR:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 RX FRMR(%d) %02X "
"%02X %02X %02X %02X\n", lapb->dev, frame->pf,
skb->data[0], skb->data[1], skb->data[2],
skb->data[3], skb->data[4]);
#endif
lapb_establish_data_link(lapb);
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S1\n",
lapb->dev);
#endif
lapb_requeue_frames(lapb);
lapb->state = LAPB_STATE_1;
break;
case LAPB_ILLEGAL:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 RX ILLEGAL(%d)\n",
lapb->dev, frame->pf);
#endif
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_W;
lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n", lapb->dev);
#endif
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
break;
}
if (!queued)
kfree_skb(skb);
}
/*
* State machine for state 4, Frame Reject State.
* The handling of the timer(s) is in file lapb_timer.c.
*/
static void lapb_state4_machine(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
switch (frame->type) {
case LAPB_SABM:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S4 RX SABM(%d)\n",
lapb->dev, frame->pf);
#endif
if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S4 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
} else {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S4 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n",
lapb->dev);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_3;
lapb->condition = 0x00;
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) S4 RX SABME(%d)\n",
lapb->dev, frame->pf);
#endif
if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S4 TX UA(%d)\n",
lapb->dev, frame->pf);
#endif
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n",
lapb->dev);
#endif
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_3;
lapb->condition = 0x00;
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) S4 TX DM(%d)\n",
lapb->dev, frame->pf);
#endif
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
}
break;
}
kfree_skb(skb);
}
/*
* Process an incoming LAPB frame
*/
void lapb_data_input(struct lapb_cb *lapb, struct sk_buff *skb)
{
struct lapb_frame frame;
if (lapb_decode(lapb, skb, &frame) < 0) {
kfree_skb(skb);
return;
}
switch (lapb->state) {
case LAPB_STATE_0:
lapb_state0_machine(lapb, skb, &frame); break;
case LAPB_STATE_1:
lapb_state1_machine(lapb, skb, &frame); break;
case LAPB_STATE_2:
lapb_state2_machine(lapb, skb, &frame); break;
case LAPB_STATE_3:
lapb_state3_machine(lapb, skb, &frame); break;
case LAPB_STATE_4:
lapb_state4_machine(lapb, skb, &frame); break;
}
lapb_kick(lapb);
}