/* * 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) */ #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 <asm/system.h> #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <net/rose.h> /* * This procedure is passed a buffer descriptor for an iframe. It builds * the rest of the control part of the frame and then writes it out. */ static void rose_send_iframe(struct sock *sk, struct sk_buff *skb) { struct rose_sock *rose = rose_sk(sk); if (skb == NULL) return; skb->data[2] |= (rose->vr << 5) & 0xE0; skb->data[2] |= (rose->vs << 1) & 0x0E; rose_start_idletimer(sk); rose_transmit_link(skb, rose->neighbour); } void rose_kick(struct sock *sk) { struct rose_sock *rose = rose_sk(sk); struct sk_buff *skb, *skbn; unsigned short start, end; if (rose->state != ROSE_STATE_3) return; if (rose->condition & ROSE_COND_PEER_RX_BUSY) return; if (!skb_peek(&sk->sk_write_queue)) return; start = (skb_peek(&rose->ack_queue) == NULL) ? rose->va : rose->vs; end = (rose->va + sysctl_rose_window_size) % ROSE_MODULUS; if (start == end) return; rose->vs = start; /* * Transmit data until either we're out of data to send or * the window is full. */ skb = skb_dequeue(&sk->sk_write_queue); do { if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { skb_queue_head(&sk->sk_write_queue, skb); break; } skb_set_owner_w(skbn, sk); /* * Transmit the frame copy. */ rose_send_iframe(sk, skbn); rose->vs = (rose->vs + 1) % ROSE_MODULUS; /* * Requeue the original data frame. */ skb_queue_tail(&rose->ack_queue, skb); } while (rose->vs != end && (skb = skb_dequeue(&sk->sk_write_queue)) != NULL); rose->vl = rose->vr; rose->condition &= ~ROSE_COND_ACK_PENDING; rose_stop_timer(sk); } /* * The following routines are taken from page 170 of the 7th ARRL Computer * Networking Conference paper, as is the whole state machine. */ void rose_enquiry_response(struct sock *sk) { struct rose_sock *rose = rose_sk(sk); if (rose->condition & ROSE_COND_OWN_RX_BUSY) rose_write_internal(sk, ROSE_RNR); else rose_write_internal(sk, ROSE_RR); rose->vl = rose->vr; rose->condition &= ~ROSE_COND_ACK_PENDING; rose_stop_timer(sk); }