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
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
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
55 void rose_stop_ftimer(struct rose_neigh *neigh)
56 {
57 del_timer(&neigh->ftimer);
58 }
59
60 void rose_stop_t0timer(struct rose_neigh *neigh)
61 {
62 del_timer(&neigh->t0timer);
63 }
64
65 int rose_ftimer_running(struct rose_neigh *neigh)
66 {
67 return timer_pending(&neigh->ftimer);
68 }
69
70 static int rose_t0timer_running(struct rose_neigh *neigh)
71 {
72 return timer_pending(&neigh->t0timer);
73 }
74
75 static void rose_ftimer_expiry(struct timer_list *t)
76 {
77 }
78
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 */
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 */
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 */
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 */
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 */
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 */
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
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
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