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net/rose/rose_in.c 7.52 KB
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  /*
   * 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.
   *
   * 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>
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  #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>
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  #include <net/tcp_states.h>
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  #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);
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  			if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 &&
  			    __sock_queue_rcv_skb(sk, skb) == 0) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  				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) >
95b7d924a   Eric Dumazet   [ROSE]: Supress s...
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  			    (sk->sk_rcvbuf >> 1))
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  				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
  ", 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);
  	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;
  }