| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This program is free software; you can redistribute it and/or modify |
| 3 | * it under the terms of the GNU General Public License as published by |
| 4 | * the Free Software Foundation; either version 2 of the License, or |
| 5 | * (at your option) any later version. |
| 6 | * |
| 7 | * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) |
| 8 | */ |
| 9 | #include <linux/errno.h> |
| 10 | #include <linux/types.h> |
| 11 | #include <linux/socket.h> |
| 12 | #include <linux/in.h> |
| 13 | #include <linux/kernel.h> |
| 14 | #include <linux/sched.h> |
| 15 | #include <linux/timer.h> |
| 16 | #include <linux/string.h> |
| 17 | #include <linux/sockios.h> |
| 18 | #include <linux/net.h> |
| 19 | #include <net/ax25.h> |
| 20 | #include <linux/inet.h> |
| 21 | #include <linux/netdevice.h> |
| 22 | #include <linux/skbuff.h> |
| 23 | #include <net/sock.h> |
| 24 | #include <asm/system.h> |
| 25 | #include <linux/fcntl.h> |
| 26 | #include <linux/mm.h> |
| 27 | #include <linux/interrupt.h> |
| 28 | #include <net/rose.h> |
| 29 | |
| 30 | /* |
| 31 | * This procedure is passed a buffer descriptor for an iframe. It builds |
| 32 | * the rest of the control part of the frame and then writes it out. |
| 33 | */ |
| 34 | static void rose_send_iframe(struct sock *sk, struct sk_buff *skb) |
| 35 | { |
| 36 | struct rose_sock *rose = rose_sk(sk); |
| 37 | |
| 38 | if (skb == NULL) |
| 39 | return; |
| 40 | |
| 41 | skb->data[2] |= (rose->vr << 5) & 0xE0; |
| 42 | skb->data[2] |= (rose->vs << 1) & 0x0E; |
| 43 | |
| 44 | rose_start_idletimer(sk); |
| 45 | |
| 46 | rose_transmit_link(skb, rose->neighbour); |
| 47 | } |
| 48 | |
| 49 | void rose_kick(struct sock *sk) |
| 50 | { |
| 51 | struct rose_sock *rose = rose_sk(sk); |
| 52 | struct sk_buff *skb, *skbn; |
| 53 | unsigned short start, end; |
| 54 | |
| 55 | if (rose->state != ROSE_STATE_3) |
| 56 | return; |
| 57 | |
| 58 | if (rose->condition & ROSE_COND_PEER_RX_BUSY) |
| 59 | return; |
| 60 | |
| 61 | if (!skb_peek(&sk->sk_write_queue)) |
| 62 | return; |
| 63 | |
| 64 | start = (skb_peek(&rose->ack_queue) == NULL) ? rose->va : rose->vs; |
| 65 | end = (rose->va + sysctl_rose_window_size) % ROSE_MODULUS; |
| 66 | |
| 67 | if (start == end) |
| 68 | return; |
| 69 | |
| 70 | rose->vs = start; |
| 71 | |
| 72 | /* |
| 73 | * Transmit data until either we're out of data to send or |
| 74 | * the window is full. |
| 75 | */ |
| 76 | |
| 77 | skb = skb_dequeue(&sk->sk_write_queue); |
| 78 | |
| 79 | do { |
| 80 | if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { |
| 81 | skb_queue_head(&sk->sk_write_queue, skb); |
| 82 | break; |
| 83 | } |
| 84 | |
| 85 | skb_set_owner_w(skbn, sk); |
| 86 | |
| 87 | /* |
| 88 | * Transmit the frame copy. |
| 89 | */ |
| 90 | rose_send_iframe(sk, skbn); |
| 91 | |
| 92 | rose->vs = (rose->vs + 1) % ROSE_MODULUS; |
| 93 | |
| 94 | /* |
| 95 | * Requeue the original data frame. |
| 96 | */ |
| 97 | skb_queue_tail(&rose->ack_queue, skb); |
| 98 | |
| 99 | } while (rose->vs != end && |
| 100 | (skb = skb_dequeue(&sk->sk_write_queue)) != NULL); |
| 101 | |
| 102 | rose->vl = rose->vr; |
| 103 | rose->condition &= ~ROSE_COND_ACK_PENDING; |
| 104 | |
| 105 | rose_stop_timer(sk); |
| 106 | } |
| 107 | |
| 108 | /* |
| 109 | * The following routines are taken from page 170 of the 7th ARRL Computer |
| 110 | * Networking Conference paper, as is the whole state machine. |
| 111 | */ |
| 112 | |
| 113 | void rose_enquiry_response(struct sock *sk) |
| 114 | { |
| 115 | struct rose_sock *rose = rose_sk(sk); |
| 116 | |
| 117 | if (rose->condition & ROSE_COND_OWN_RX_BUSY) |
| 118 | rose_write_internal(sk, ROSE_RNR); |
| 119 | else |
| 120 | rose_write_internal(sk, ROSE_RR); |
| 121 | |
| 122 | rose->vl = rose->vr; |
| 123 | rose->condition &= ~ROSE_COND_ACK_PENDING; |
| 124 | |
| 125 | rose_stop_timer(sk); |
| 126 | } |