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rose_link.c
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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 ([email protected])
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 <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 =
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 =
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 
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 
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) {
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 
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 
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 (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 }