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linux/net/rose/rose_in.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 
Based on 1 normalized pattern(s):

  this program 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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
*
* Most of this code is based on the SDL diagrams published in the 7th ARRL
* Computer Networking Conference papers. The diagrams have mistakes in them,
* but are mostly correct. Before you modify the code could you read the SDL
* diagrams as the code is not obvious and probably very easy to break.
*/
#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 <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/rose.h>
/*
* State machine for state 1, Awaiting Call Accepted State.
* The handling of the timer(s) is in file rose_timer.c.
* Handling of state 0 and connection release is in af_rose.c.
*/
static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
struct rose_sock *rose = rose_sk(sk);
switch (frametype) {
case ROSE_CALL_ACCEPTED:
rose_stop_timer(sk);
rose_start_idletimer(sk);
rose->condition = 0x00;
rose->vs = 0;
rose->va = 0;
rose->vr = 0;
rose->vl = 0;
rose->state = ROSE_STATE_3;
sk->sk_state = TCP_ESTABLISHED;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
break;
case ROSE_CLEAR_REQUEST:
rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
rose->neighbour->use--;
break;
default:
break;
}
return 0;
}
/*
* State machine for state 2, Awaiting Clear Confirmation State.
* The handling of the timer(s) is in file rose_timer.c
* Handling of state 0 and connection release is in af_rose.c.
*/
static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
struct rose_sock *rose = rose_sk(sk);
switch (frametype) {
case ROSE_CLEAR_REQUEST:
rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
rose->neighbour->use--;
break;
case ROSE_CLEAR_CONFIRMATION:
rose_disconnect(sk, 0, -1, -1);
rose->neighbour->use--;
break;
default:
break;
}
return 0;
}
/*
* State machine for state 3, Connected State.
* The handling of the timer(s) is in file rose_timer.c
* Handling of state 0 and connection release is in af_rose.c.
*/
static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
{
struct rose_sock *rose = rose_sk(sk);
int queued = 0;
switch (frametype) {
case ROSE_RESET_REQUEST:
rose_stop_timer(sk);
rose_start_idletimer(sk);
rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
rose->condition = 0x00;
rose->vs = 0;
rose->vr = 0;
rose->va = 0;
rose->vl = 0;
rose_requeue_frames(sk);
break;
case ROSE_CLEAR_REQUEST:
rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
rose->neighbour->use--;
break;
case ROSE_RR:
case ROSE_RNR:
if (!rose_validate_nr(sk, nr)) {
rose_write_internal(sk, ROSE_RESET_REQUEST);
rose->condition = 0x00;
rose->vs = 0;
rose->vr = 0;
rose->va = 0;
rose->vl = 0;
rose->state = ROSE_STATE_4;
rose_start_t2timer(sk);
rose_stop_idletimer(sk);
} else {
rose_frames_acked(sk, nr);
if (frametype == ROSE_RNR) {
rose->condition |= ROSE_COND_PEER_RX_BUSY;
} else {
rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
}
}
break;
case ROSE_DATA: /* XXX */
rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
if (!rose_validate_nr(sk, nr)) {
rose_write_internal(sk, ROSE_RESET_REQUEST);
rose->condition = 0x00;
rose->vs = 0;
rose->vr = 0;
rose->va = 0;
rose->vl = 0;
rose->state = ROSE_STATE_4;
rose_start_t2timer(sk);
rose_stop_idletimer(sk);
break;
}
rose_frames_acked(sk, nr);
if (ns == rose->vr) {
rose_start_idletimer(sk);
if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 &&
__sock_queue_rcv_skb(sk, skb) == 0) {
rose->vr = (rose->vr + 1) % ROSE_MODULUS;
queued = 1;
} else {
/* Should never happen ! */
rose_write_internal(sk, ROSE_RESET_REQUEST);
rose->condition = 0x00;
rose->vs = 0;
rose->vr = 0;
rose->va = 0;
rose->vl = 0;
rose->state = ROSE_STATE_4;
rose_start_t2timer(sk);
rose_stop_idletimer(sk);
break;
}
if (atomic_read(&sk->sk_rmem_alloc) >
(sk->sk_rcvbuf >> 1))
rose->condition |= ROSE_COND_OWN_RX_BUSY;
}
/*
* If the window is full, ack the frame, else start the
* acknowledge hold back timer.
*/
if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
rose->condition &= ~ROSE_COND_ACK_PENDING;
rose_stop_timer(sk);
rose_enquiry_response(sk);
} else {
rose->condition |= ROSE_COND_ACK_PENDING;
rose_start_hbtimer(sk);
}
break;
default:
printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
break;
}
return queued;
}
/*
* State machine for state 4, Awaiting Reset Confirmation State.
* The handling of the timer(s) is in file rose_timer.c
* Handling of state 0 and connection release is in af_rose.c.
*/
static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
struct rose_sock *rose = rose_sk(sk);
switch (frametype) {
case ROSE_RESET_REQUEST:
rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
/* fall through */
case ROSE_RESET_CONFIRMATION:
rose_stop_timer(sk);
rose_start_idletimer(sk);
rose->condition = 0x00;
rose->va = 0;
rose->vr = 0;
rose->vs = 0;
rose->vl = 0;
rose->state = ROSE_STATE_3;
rose_requeue_frames(sk);
break;
case ROSE_CLEAR_REQUEST:
rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
rose->neighbour->use--;
break;
default:
break;
}
return 0;
}
/*
* State machine for state 5, Awaiting Call Acceptance State.
* The handling of the timer(s) is in file rose_timer.c
* Handling of state 0 and connection release is in af_rose.c.
*/
static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
if (frametype == ROSE_CLEAR_REQUEST) {
rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
rose_sk(sk)->neighbour->use--;
}
return 0;
}
/* Higher level upcall for a LAPB frame */
int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
{
struct rose_sock *rose = rose_sk(sk);
int queued = 0, frametype, ns, nr, q, d, m;
if (rose->state == ROSE_STATE_0)
return 0;
frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
switch (rose->state) {
case ROSE_STATE_1:
queued = rose_state1_machine(sk, skb, frametype);
break;
case ROSE_STATE_2:
queued = rose_state2_machine(sk, skb, frametype);
break;
case ROSE_STATE_3:
queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
break;
case ROSE_STATE_4:
queued = rose_state4_machine(sk, skb, frametype);
break;
case ROSE_STATE_5:
queued = rose_state5_machine(sk, skb, frametype);
break;
}
rose_kick(sk);
return queued;
}
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