net/rose/rose_in.c - linux - Git at Google

 // 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/filter.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);
 		fallthrough;
 	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;
 }
	// 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/filter.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);
	fallthrough;
	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;
	}