1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun #include <linux/errno.h>
7*4882a593Smuzhiyun #include <linux/types.h>
8*4882a593Smuzhiyun #include <linux/socket.h>
9*4882a593Smuzhiyun #include <linux/in.h>
10*4882a593Smuzhiyun #include <linux/kernel.h>
11*4882a593Smuzhiyun #include <linux/timer.h>
12*4882a593Smuzhiyun #include <linux/string.h>
13*4882a593Smuzhiyun #include <linux/sockios.h>
14*4882a593Smuzhiyun #include <linux/net.h>
15*4882a593Smuzhiyun #include <linux/gfp.h>
16*4882a593Smuzhiyun #include <net/ax25.h>
17*4882a593Smuzhiyun #include <linux/inet.h>
18*4882a593Smuzhiyun #include <linux/netdevice.h>
19*4882a593Smuzhiyun #include <linux/skbuff.h>
20*4882a593Smuzhiyun #include <net/sock.h>
21*4882a593Smuzhiyun #include <linux/fcntl.h>
22*4882a593Smuzhiyun #include <linux/mm.h>
23*4882a593Smuzhiyun #include <linux/interrupt.h>
24*4882a593Smuzhiyun #include <net/rose.h>
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun /*
27*4882a593Smuzhiyun * This procedure is passed a buffer descriptor for an iframe. It builds
28*4882a593Smuzhiyun * the rest of the control part of the frame and then writes it out.
29*4882a593Smuzhiyun */
rose_send_iframe(struct sock * sk,struct sk_buff * skb)30*4882a593Smuzhiyun static void rose_send_iframe(struct sock *sk, struct sk_buff *skb)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun struct rose_sock *rose = rose_sk(sk);
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun if (skb == NULL)
35*4882a593Smuzhiyun return;
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun skb->data[2] |= (rose->vr << 5) & 0xE0;
38*4882a593Smuzhiyun skb->data[2] |= (rose->vs << 1) & 0x0E;
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun rose_start_idletimer(sk);
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun rose_transmit_link(skb, rose->neighbour);
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun
rose_kick(struct sock * sk)45*4882a593Smuzhiyun void rose_kick(struct sock *sk)
46*4882a593Smuzhiyun {
47*4882a593Smuzhiyun struct rose_sock *rose = rose_sk(sk);
48*4882a593Smuzhiyun struct sk_buff *skb, *skbn;
49*4882a593Smuzhiyun unsigned short start, end;
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun if (rose->state != ROSE_STATE_3)
52*4882a593Smuzhiyun return;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun if (rose->condition & ROSE_COND_PEER_RX_BUSY)
55*4882a593Smuzhiyun return;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun if (!skb_peek(&sk->sk_write_queue))
58*4882a593Smuzhiyun return;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun start = (skb_peek(&rose->ack_queue) == NULL) ? rose->va : rose->vs;
61*4882a593Smuzhiyun end = (rose->va + sysctl_rose_window_size) % ROSE_MODULUS;
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun if (start == end)
64*4882a593Smuzhiyun return;
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun rose->vs = start;
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun /*
69*4882a593Smuzhiyun * Transmit data until either we're out of data to send or
70*4882a593Smuzhiyun * the window is full.
71*4882a593Smuzhiyun */
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun skb = skb_dequeue(&sk->sk_write_queue);
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun do {
76*4882a593Smuzhiyun if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
77*4882a593Smuzhiyun skb_queue_head(&sk->sk_write_queue, skb);
78*4882a593Smuzhiyun break;
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun skb_set_owner_w(skbn, sk);
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun /*
84*4882a593Smuzhiyun * Transmit the frame copy.
85*4882a593Smuzhiyun */
86*4882a593Smuzhiyun rose_send_iframe(sk, skbn);
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun rose->vs = (rose->vs + 1) % ROSE_MODULUS;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun /*
91*4882a593Smuzhiyun * Requeue the original data frame.
92*4882a593Smuzhiyun */
93*4882a593Smuzhiyun skb_queue_tail(&rose->ack_queue, skb);
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun } while (rose->vs != end &&
96*4882a593Smuzhiyun (skb = skb_dequeue(&sk->sk_write_queue)) != NULL);
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun rose->vl = rose->vr;
99*4882a593Smuzhiyun rose->condition &= ~ROSE_COND_ACK_PENDING;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun rose_stop_timer(sk);
102*4882a593Smuzhiyun }
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun /*
105*4882a593Smuzhiyun * The following routines are taken from page 170 of the 7th ARRL Computer
106*4882a593Smuzhiyun * Networking Conference paper, as is the whole state machine.
107*4882a593Smuzhiyun */
108*4882a593Smuzhiyun
rose_enquiry_response(struct sock * sk)109*4882a593Smuzhiyun void rose_enquiry_response(struct sock *sk)
110*4882a593Smuzhiyun {
111*4882a593Smuzhiyun struct rose_sock *rose = rose_sk(sk);
112*4882a593Smuzhiyun
113*4882a593Smuzhiyun if (rose->condition & ROSE_COND_OWN_RX_BUSY)
114*4882a593Smuzhiyun rose_write_internal(sk, ROSE_RNR);
115*4882a593Smuzhiyun else
116*4882a593Smuzhiyun rose_write_internal(sk, ROSE_RR);
117*4882a593Smuzhiyun
118*4882a593Smuzhiyun rose->vl = rose->vr;
119*4882a593Smuzhiyun rose->condition &= ~ROSE_COND_ACK_PENDING;
120*4882a593Smuzhiyun
121*4882a593Smuzhiyun rose_stop_timer(sk);
122*4882a593Smuzhiyun }
123