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/jiffies.h>
15#include <linux/timer.h>
16#include <linux/string.h>
17#include <linux/sockios.h>
18#include <linux/net.h>
19#include <linux/slab.h>
20#include <net/ax25.h>
21#include <linux/inet.h>
22#include <linux/netdevice.h>
23#include <linux/skbuff.h>
24#include <net/sock.h>
25#include <linux/fcntl.h>
26#include <linux/mm.h>
27#include <linux/interrupt.h>
28#include <linux/netfilter.h>
29#include <net/rose.h>
30
31static void rose_ftimer_expiry(unsigned long);
32static void rose_t0timer_expiry(unsigned long);
33
34static void rose_transmit_restart_confirmation(struct rose_neigh *neigh);
35static void rose_transmit_restart_request(struct rose_neigh *neigh);
36
37void rose_start_ftimer(struct rose_neigh *neigh)
38{
39	del_timer(&neigh->ftimer);
40
41	neigh->ftimer.data     = (unsigned long)neigh;
42	neigh->ftimer.function = &rose_ftimer_expiry;
43	neigh->ftimer.expires  =
44		jiffies + msecs_to_jiffies(sysctl_rose_link_fail_timeout);
45
46	add_timer(&neigh->ftimer);
47}
48
49static void rose_start_t0timer(struct rose_neigh *neigh)
50{
51	del_timer(&neigh->t0timer);
52
53	neigh->t0timer.data     = (unsigned long)neigh;
54	neigh->t0timer.function = &rose_t0timer_expiry;
55	neigh->t0timer.expires  =
56		jiffies + msecs_to_jiffies(sysctl_rose_restart_request_timeout);
57
58	add_timer(&neigh->t0timer);
59}
60
61void rose_stop_ftimer(struct rose_neigh *neigh)
62{
63	del_timer(&neigh->ftimer);
64}
65
66void rose_stop_t0timer(struct rose_neigh *neigh)
67{
68	del_timer(&neigh->t0timer);
69}
70
71int rose_ftimer_running(struct rose_neigh *neigh)
72{
73	return timer_pending(&neigh->ftimer);
74}
75
76static int rose_t0timer_running(struct rose_neigh *neigh)
77{
78	return timer_pending(&neigh->t0timer);
79}
80
81static void rose_ftimer_expiry(unsigned long param)
82{
83}
84
85static void rose_t0timer_expiry(unsigned long param)
86{
87	struct rose_neigh *neigh = (struct rose_neigh *)param;
88
89	rose_transmit_restart_request(neigh);
90
91	neigh->dce_mode = 0;
92
93	rose_start_t0timer(neigh);
94}
95
96/*
97 *	Interface to ax25_send_frame. Changes my level 2 callsign depending
98 *	on whether we have a global ROSE callsign or use the default port
99 *	callsign.
100 */
101static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
102{
103	ax25_address *rose_call;
104	ax25_cb *ax25s;
105
106	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
107		rose_call = (ax25_address *)neigh->dev->dev_addr;
108	else
109		rose_call = &rose_callsign;
110
111	ax25s = neigh->ax25;
112	neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
113	if (ax25s)
114		ax25_cb_put(ax25s);
115
116	return neigh->ax25 != NULL;
117}
118
119/*
120 *	Interface to ax25_link_up. Changes my level 2 callsign depending
121 *	on whether we have a global ROSE callsign or use the default port
122 *	callsign.
123 */
124static int rose_link_up(struct rose_neigh *neigh)
125{
126	ax25_address *rose_call;
127	ax25_cb *ax25s;
128
129	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
130		rose_call = (ax25_address *)neigh->dev->dev_addr;
131	else
132		rose_call = &rose_callsign;
133
134	ax25s = neigh->ax25;
135	neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
136	if (ax25s)
137		ax25_cb_put(ax25s);
138
139	return neigh->ax25 != NULL;
140}
141
142/*
143 *	This handles all restart and diagnostic frames.
144 */
145void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
146{
147	struct sk_buff *skbn;
148
149	switch (frametype) {
150	case ROSE_RESTART_REQUEST:
151		rose_stop_t0timer(neigh);
152		neigh->restarted = 1;
153		neigh->dce_mode  = (skb->data[3] == ROSE_DTE_ORIGINATED);
154		rose_transmit_restart_confirmation(neigh);
155		break;
156
157	case ROSE_RESTART_CONFIRMATION:
158		rose_stop_t0timer(neigh);
159		neigh->restarted = 1;
160		break;
161
162	case ROSE_DIAGNOSTIC:
163		pr_warn("ROSE: received diagnostic #%d - %3ph\n", skb->data[3],
164			skb->data + 4);
165		break;
166
167	default:
168		printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
169		break;
170	}
171
172	if (neigh->restarted) {
173		while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
174			if (!rose_send_frame(skbn, neigh))
175				kfree_skb(skbn);
176	}
177}
178
179/*
180 *	This routine is called when a Restart Request is needed
181 */
182static void rose_transmit_restart_request(struct rose_neigh *neigh)
183{
184	struct sk_buff *skb;
185	unsigned char *dptr;
186	int len;
187
188	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
189
190	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
191		return;
192
193	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
194
195	dptr = skb_put(skb, ROSE_MIN_LEN + 3);
196
197	*dptr++ = AX25_P_ROSE;
198	*dptr++ = ROSE_GFI;
199	*dptr++ = 0x00;
200	*dptr++ = ROSE_RESTART_REQUEST;
201	*dptr++ = ROSE_DTE_ORIGINATED;
202	*dptr++ = 0;
203
204	if (!rose_send_frame(skb, neigh))
205		kfree_skb(skb);
206}
207
208/*
209 * This routine is called when a Restart Confirmation is needed
210 */
211static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
212{
213	struct sk_buff *skb;
214	unsigned char *dptr;
215	int len;
216
217	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
218
219	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
220		return;
221
222	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
223
224	dptr = skb_put(skb, ROSE_MIN_LEN + 1);
225
226	*dptr++ = AX25_P_ROSE;
227	*dptr++ = ROSE_GFI;
228	*dptr++ = 0x00;
229	*dptr++ = ROSE_RESTART_CONFIRMATION;
230
231	if (!rose_send_frame(skb, neigh))
232		kfree_skb(skb);
233}
234
235/*
236 * This routine is called when a Clear Request is needed outside of the context
237 * of a connected socket.
238 */
239void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
240{
241	struct sk_buff *skb;
242	unsigned char *dptr;
243	int len;
244
245	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
246
247	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
248		return;
249
250	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
251
252	dptr = skb_put(skb, ROSE_MIN_LEN + 3);
253
254	*dptr++ = AX25_P_ROSE;
255	*dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
256	*dptr++ = ((lci >> 0) & 0xFF);
257	*dptr++ = ROSE_CLEAR_REQUEST;
258	*dptr++ = cause;
259	*dptr++ = diagnostic;
260
261	if (!rose_send_frame(skb, neigh))
262		kfree_skb(skb);
263}
264
265void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
266{
267	unsigned char *dptr;
268
269	if (neigh->loopback) {
270		rose_loopback_queue(skb, neigh);
271		return;
272	}
273
274	if (!rose_link_up(neigh))
275		neigh->restarted = 0;
276
277	dptr = skb_push(skb, 1);
278	*dptr++ = AX25_P_ROSE;
279
280	if (neigh->restarted) {
281		if (!rose_send_frame(skb, neigh))
282			kfree_skb(skb);
283	} else {
284		skb_queue_tail(&neigh->queue, skb);
285
286		if (!rose_t0timer_running(neigh)) {
287			rose_transmit_restart_request(neigh);
288			neigh->dce_mode = 0;
289			rose_start_t0timer(neigh);
290		}
291	}
292}
293