xref: /linux/net/rose/rose_link.c (revision 7ae9fb1b7ecbb5d85d07857943f677fd1a559b18)
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 
27 static void rose_ftimer_expiry(struct timer_list *);
28 static void rose_t0timer_expiry(struct timer_list *);
29 
30 static void rose_transmit_restart_confirmation(struct rose_neigh *neigh);
31 static void rose_transmit_restart_request(struct rose_neigh *neigh);
32 
rose_start_ftimer(struct rose_neigh * neigh)33 void 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 
rose_start_t0timer(struct rose_neigh * neigh)44 static 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 
rose_stop_ftimer(struct rose_neigh * neigh)55 void rose_stop_ftimer(struct rose_neigh *neigh)
56 {
57 	del_timer(&neigh->ftimer);
58 }
59 
rose_stop_t0timer(struct rose_neigh * neigh)60 void rose_stop_t0timer(struct rose_neigh *neigh)
61 {
62 	del_timer(&neigh->t0timer);
63 }
64 
rose_ftimer_running(struct rose_neigh * neigh)65 int rose_ftimer_running(struct rose_neigh *neigh)
66 {
67 	return timer_pending(&neigh->ftimer);
68 }
69 
rose_t0timer_running(struct rose_neigh * neigh)70 static int rose_t0timer_running(struct rose_neigh *neigh)
71 {
72 	return timer_pending(&neigh->t0timer);
73 }
74 
rose_ftimer_expiry(struct timer_list * t)75 static void rose_ftimer_expiry(struct timer_list *t)
76 {
77 }
78 
rose_t0timer_expiry(struct timer_list * t)79 static 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  */
rose_send_frame(struct sk_buff * skb,struct rose_neigh * neigh)95 static 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  */
rose_link_up(struct rose_neigh * neigh)118 static 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  */
rose_link_rx_restart(struct sk_buff * skb,struct rose_neigh * neigh,unsigned short frametype)139 void 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  */
rose_transmit_restart_request(struct rose_neigh * neigh)176 static 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  */
rose_transmit_restart_confirmation(struct rose_neigh * neigh)205 static 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  */
rose_transmit_clear_request(struct rose_neigh * neigh,unsigned int lci,unsigned char cause,unsigned char diagnostic)233 void 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 
rose_transmit_link(struct sk_buff * skb,struct rose_neigh * neigh)262 void 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