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