xref: /openbmc/linux/net/rose/rose_link.c (revision b6dcefde)
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 
31 static void rose_ftimer_expiry(unsigned long);
32 static void rose_t0timer_expiry(unsigned long);
33 
34 static void rose_transmit_restart_confirmation(struct rose_neigh *neigh);
35 static void rose_transmit_restart_request(struct rose_neigh *neigh);
36 
37 void 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 
49 static 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 
61 void rose_stop_ftimer(struct rose_neigh *neigh)
62 {
63 	del_timer(&neigh->ftimer);
64 }
65 
66 void rose_stop_t0timer(struct rose_neigh *neigh)
67 {
68 	del_timer(&neigh->t0timer);
69 }
70 
71 int rose_ftimer_running(struct rose_neigh *neigh)
72 {
73 	return timer_pending(&neigh->ftimer);
74 }
75 
76 static int rose_t0timer_running(struct rose_neigh *neigh)
77 {
78 	return timer_pending(&neigh->t0timer);
79 }
80 
81 static void rose_ftimer_expiry(unsigned long param)
82 {
83 }
84 
85 static 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  */
101 static 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  */
124 static 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  */
145 void 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 		printk(KERN_WARNING "ROSE: received diagnostic #%d - %02X %02X %02X\n", skb->data[3], skb->data[4], skb->data[5], skb->data[6]);
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  */
181 static 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  */
210 static 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  */
238 void 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 
264 void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
265 {
266 	unsigned char *dptr;
267 
268 #if 0
269 	if (call_fw_firewall(PF_ROSE, skb->dev, skb->data, NULL, &skb) != FW_ACCEPT) {
270 		kfree_skb(skb);
271 		return;
272 	}
273 #endif
274 
275 	if (neigh->loopback) {
276 		rose_loopback_queue(skb, neigh);
277 		return;
278 	}
279 
280 	if (!rose_link_up(neigh))
281 		neigh->restarted = 0;
282 
283 	dptr = skb_push(skb, 1);
284 	*dptr++ = AX25_P_ROSE;
285 
286 	if (neigh->restarted) {
287 		if (!rose_send_frame(skb, neigh))
288 			kfree_skb(skb);
289 	} else {
290 		skb_queue_tail(&neigh->queue, skb);
291 
292 		if (!rose_t0timer_running(neigh)) {
293 			rose_transmit_restart_request(neigh);
294 			neigh->dce_mode = 0;
295 			rose_start_t0timer(neigh);
296 		}
297 	}
298 }
299