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 <net/ax25.h>
20#include <linux/inet.h>
21#include <linux/netdevice.h>
22#include <linux/skbuff.h>
23#include <net/sock.h>
24#include <asm/system.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
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	neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
111
112	return (neigh->ax25 != NULL);
113}
114
115/*
116 *	Interface to ax25_link_up. Changes my level 2 callsign depending
117 *	on whether we have a global ROSE callsign or use the default port
118 *	callsign.
119 */
120static int rose_link_up(struct rose_neigh *neigh)
121{
122	ax25_address *rose_call;
123
124	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
125		rose_call = (ax25_address *)neigh->dev->dev_addr;
126	else
127		rose_call = &rose_callsign;
128
129	neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
130
131	return (neigh->ax25 != NULL);
132}
133
134/*
135 *	This handles all restart and diagnostic frames.
136 */
137void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
138{
139	struct sk_buff *skbn;
140
141	switch (frametype) {
142	case ROSE_RESTART_REQUEST:
143		rose_stop_t0timer(neigh);
144		neigh->restarted = 1;
145		neigh->dce_mode  = (skb->data[3] == ROSE_DTE_ORIGINATED);
146		rose_transmit_restart_confirmation(neigh);
147		break;
148
149	case ROSE_RESTART_CONFIRMATION:
150		rose_stop_t0timer(neigh);
151		neigh->restarted = 1;
152		break;
153
154	case ROSE_DIAGNOSTIC:
155		printk(KERN_WARNING "ROSE: received diagnostic #%d - %02X %02X %02X\n", skb->data[3], skb->data[4], skb->data[5], skb->data[6]);
156		break;
157
158	default:
159		printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
160		break;
161	}
162
163	if (neigh->restarted) {
164		while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
165			if (!rose_send_frame(skbn, neigh))
166				kfree_skb(skbn);
167	}
168}
169
170/*
171 *	This routine is called when a Restart Request is needed
172 */
173static void rose_transmit_restart_request(struct rose_neigh *neigh)
174{
175	struct sk_buff *skb;
176	unsigned char *dptr;
177	int len;
178
179	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
180
181	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
182		return;
183
184	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
185
186	dptr = skb_put(skb, ROSE_MIN_LEN + 3);
187
188	*dptr++ = AX25_P_ROSE;
189	*dptr++ = ROSE_GFI;
190	*dptr++ = 0x00;
191	*dptr++ = ROSE_RESTART_REQUEST;
192	*dptr++ = ROSE_DTE_ORIGINATED;
193	*dptr++ = 0;
194
195	if (!rose_send_frame(skb, neigh))
196		kfree_skb(skb);
197}
198
199/*
200 * This routine is called when a Restart Confirmation is needed
201 */
202static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
203{
204	struct sk_buff *skb;
205	unsigned char *dptr;
206	int len;
207
208	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
209
210	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
211		return;
212
213	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
214
215	dptr = skb_put(skb, ROSE_MIN_LEN + 1);
216
217	*dptr++ = AX25_P_ROSE;
218	*dptr++ = ROSE_GFI;
219	*dptr++ = 0x00;
220	*dptr++ = ROSE_RESTART_CONFIRMATION;
221
222	if (!rose_send_frame(skb, neigh))
223		kfree_skb(skb);
224}
225
226/*
227 * This routine is called when a Clear Request is needed outside of the context
228 * of a connected socket.
229 */
230void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
231{
232	struct sk_buff *skb;
233	unsigned char *dptr;
234	int len;
235
236	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
237
238	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
239		return;
240
241	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
242
243	dptr = skb_put(skb, ROSE_MIN_LEN + 3);
244
245	*dptr++ = AX25_P_ROSE;
246	*dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
247	*dptr++ = ((lci >> 0) & 0xFF);
248	*dptr++ = ROSE_CLEAR_REQUEST;
249	*dptr++ = cause;
250	*dptr++ = diagnostic;
251
252	if (!rose_send_frame(skb, neigh))
253		kfree_skb(skb);
254}
255
256void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
257{
258	unsigned char *dptr;
259
260
261	if (neigh->loopback) {
262		rose_loopback_queue(skb, neigh);
263		return;
264	}
265
266	if (!rose_link_up(neigh))
267		neigh->restarted = 0;
268
269	dptr = skb_push(skb, 1);
270	*dptr++ = AX25_P_ROSE;
271
272	if (neigh->restarted) {
273		if (!rose_send_frame(skb, neigh))
274			kfree_skb(skb);
275	} else {
276		skb_queue_tail(&neigh->queue, skb);
277
278		if (!rose_t0timer_running(neigh)) {
279			rose_transmit_restart_request(neigh);
280			neigh->dce_mode = 0;
281			rose_start_t0timer(neigh);
282		}
283	}
284}
285