1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 */
6#include <linux/errno.h>
7#include <linux/types.h>
8#include <linux/socket.h>
9#include <linux/in.h>
10#include <linux/kernel.h>
11#include <linux/jiffies.h>
12#include <linux/timer.h>
13#include <linux/string.h>
14#include <linux/sockios.h>
15#include <linux/net.h>
16#include <linux/slab.h>
17#include <net/ax25.h>
18#include <linux/inet.h>
19#include <linux/netdevice.h>
20#include <linux/skbuff.h>
21#include <net/sock.h>
22#include <linux/fcntl.h>
23#include <linux/mm.h>
24#include <linux/interrupt.h>
25#include <net/rose.h>
26
27static void rose_ftimer_expiry(struct timer_list *);
28static void rose_t0timer_expiry(struct timer_list *);
29
30static void rose_transmit_restart_confirmation(struct rose_neigh *neigh);
31static void rose_transmit_restart_request(struct rose_neigh *neigh);
32
33void rose_start_ftimer(struct rose_neigh *neigh)
34{
35	del_timer(&neigh->ftimer);
36
37	neigh->ftimer.function = rose_ftimer_expiry;
38	neigh->ftimer.expires  =
39		jiffies + msecs_to_jiffies(sysctl_rose_link_fail_timeout);
40
41	add_timer(&neigh->ftimer);
42}
43
44static void rose_start_t0timer(struct rose_neigh *neigh)
45{
46	del_timer(&neigh->t0timer);
47
48	neigh->t0timer.function = rose_t0timer_expiry;
49	neigh->t0timer.expires  =
50		jiffies + msecs_to_jiffies(sysctl_rose_restart_request_timeout);
51
52	add_timer(&neigh->t0timer);
53}
54
55void rose_stop_ftimer(struct rose_neigh *neigh)
56{
57	del_timer(&neigh->ftimer);
58}
59
60void rose_stop_t0timer(struct rose_neigh *neigh)
61{
62	del_timer(&neigh->t0timer);
63}
64
65int rose_ftimer_running(struct rose_neigh *neigh)
66{
67	return timer_pending(&neigh->ftimer);
68}
69
70static int rose_t0timer_running(struct rose_neigh *neigh)
71{
72	return timer_pending(&neigh->t0timer);
73}
74
75static void rose_ftimer_expiry(struct timer_list *t)
76{
77}
78
79static void rose_t0timer_expiry(struct timer_list *t)
80{
81	struct rose_neigh *neigh = from_timer(neigh, t, t0timer);
82
83	rose_transmit_restart_request(neigh);
84
85	neigh->dce_mode = 0;
86
87	rose_start_t0timer(neigh);
88}
89
90/*
91 *	Interface to ax25_send_frame. Changes my level 2 callsign depending
92 *	on whether we have a global ROSE callsign or use the default port
93 *	callsign.
94 */
95static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
96{
97	const ax25_address *rose_call;
98	ax25_cb *ax25s;
99
100	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
101		rose_call = (const ax25_address *)neigh->dev->dev_addr;
102	else
103		rose_call = &rose_callsign;
104
105	ax25s = neigh->ax25;
106	neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
107	if (ax25s)
108		ax25_cb_put(ax25s);
109
110	return neigh->ax25 != NULL;
111}
112
113/*
114 *	Interface to ax25_link_up. Changes my level 2 callsign depending
115 *	on whether we have a global ROSE callsign or use the default port
116 *	callsign.
117 */
118static int rose_link_up(struct rose_neigh *neigh)
119{
120	const ax25_address *rose_call;
121	ax25_cb *ax25s;
122
123	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
124		rose_call = (const ax25_address *)neigh->dev->dev_addr;
125	else
126		rose_call = &rose_callsign;
127
128	ax25s = neigh->ax25;
129	neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
130	if (ax25s)
131		ax25_cb_put(ax25s);
132
133	return neigh->ax25 != NULL;
134}
135
136/*
137 *	This handles all restart and diagnostic frames.
138 */
139void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
140{
141	struct sk_buff *skbn;
142
143	switch (frametype) {
144	case ROSE_RESTART_REQUEST:
145		rose_stop_t0timer(neigh);
146		neigh->restarted = 1;
147		neigh->dce_mode  = (skb->data[3] == ROSE_DTE_ORIGINATED);
148		rose_transmit_restart_confirmation(neigh);
149		break;
150
151	case ROSE_RESTART_CONFIRMATION:
152		rose_stop_t0timer(neigh);
153		neigh->restarted = 1;
154		break;
155
156	case ROSE_DIAGNOSTIC:
157		pr_warn("ROSE: received diagnostic #%d - %3ph\n", skb->data[3],
158			skb->data + 4);
159		break;
160
161	default:
162		printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
163		break;
164	}
165
166	if (neigh->restarted) {
167		while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
168			if (!rose_send_frame(skbn, neigh))
169				kfree_skb(skbn);
170	}
171}
172
173/*
174 *	This routine is called when a Restart Request is needed
175 */
176static void rose_transmit_restart_request(struct rose_neigh *neigh)
177{
178	struct sk_buff *skb;
179	unsigned char *dptr;
180	int len;
181
182	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
183
184	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
185		return;
186
187	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
188
189	dptr = skb_put(skb, ROSE_MIN_LEN + 3);
190
191	*dptr++ = AX25_P_ROSE;
192	*dptr++ = ROSE_GFI;
193	*dptr++ = 0x00;
194	*dptr++ = ROSE_RESTART_REQUEST;
195	*dptr++ = ROSE_DTE_ORIGINATED;
196	*dptr++ = 0;
197
198	if (!rose_send_frame(skb, neigh))
199		kfree_skb(skb);
200}
201
202/*
203 * This routine is called when a Restart Confirmation is needed
204 */
205static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
206{
207	struct sk_buff *skb;
208	unsigned char *dptr;
209	int len;
210
211	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
212
213	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
214		return;
215
216	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
217
218	dptr = skb_put(skb, ROSE_MIN_LEN + 1);
219
220	*dptr++ = AX25_P_ROSE;
221	*dptr++ = ROSE_GFI;
222	*dptr++ = 0x00;
223	*dptr++ = ROSE_RESTART_CONFIRMATION;
224
225	if (!rose_send_frame(skb, neigh))
226		kfree_skb(skb);
227}
228
229/*
230 * This routine is called when a Clear Request is needed outside of the context
231 * of a connected socket.
232 */
233void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
234{
235	struct sk_buff *skb;
236	unsigned char *dptr;
237	int len;
238
239	if (!neigh->dev)
240		return;
241
242	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
243
244	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
245		return;
246
247	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
248
249	dptr = skb_put(skb, ROSE_MIN_LEN + 3);
250
251	*dptr++ = AX25_P_ROSE;
252	*dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
253	*dptr++ = ((lci >> 0) & 0xFF);
254	*dptr++ = ROSE_CLEAR_REQUEST;
255	*dptr++ = cause;
256	*dptr++ = diagnostic;
257
258	if (!rose_send_frame(skb, neigh))
259		kfree_skb(skb);
260}
261
262void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
263{
264	unsigned char *dptr;
265
266	if (neigh->loopback) {
267		rose_loopback_queue(skb, neigh);
268		return;
269	}
270
271	if (!rose_link_up(neigh))
272		neigh->restarted = 0;
273
274	dptr = skb_push(skb, 1);
275	*dptr++ = AX25_P_ROSE;
276
277	if (neigh->restarted) {
278		if (!rose_send_frame(skb, neigh))
279			kfree_skb(skb);
280	} else {
281		skb_queue_tail(&neigh->queue, skb);
282
283		if (!rose_t0timer_running(neigh)) {
284			rose_transmit_restart_request(neigh);
285			neigh->dce_mode = 0;
286			rose_start_t0timer(neigh);
287		}
288	}
289}
290