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1da177e4 LT |
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) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk) | |
8 | * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) | |
9 | * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de) | |
10 | */ | |
1da177e4 LT |
11 | #include <linux/errno.h> |
12 | #include <linux/types.h> | |
13 | #include <linux/socket.h> | |
14 | #include <linux/in.h> | |
15 | #include <linux/kernel.h> | |
70868eac | 16 | #include <linux/module.h> |
1da177e4 LT |
17 | #include <linux/sched.h> |
18 | #include <linux/timer.h> | |
19 | #include <linux/string.h> | |
20 | #include <linux/sockios.h> | |
21 | #include <linux/spinlock.h> | |
22 | #include <linux/net.h> | |
23 | #include <net/ax25.h> | |
24 | #include <linux/inet.h> | |
25 | #include <linux/netdevice.h> | |
26 | #include <linux/skbuff.h> | |
27 | #include <linux/netfilter.h> | |
28 | #include <net/sock.h> | |
29 | #include <asm/uaccess.h> | |
30 | #include <asm/system.h> | |
31 | #include <linux/fcntl.h> | |
32 | #include <linux/mm.h> | |
33 | #include <linux/interrupt.h> | |
34 | ||
35 | static DEFINE_SPINLOCK(ax25_frag_lock); | |
36 | ||
37 | ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, ax25_address *src, ax25_address *dest, ax25_digi *digi, struct net_device *dev) | |
38 | { | |
39 | ax25_dev *ax25_dev; | |
40 | ax25_cb *ax25; | |
41 | ||
42 | /* | |
43 | * Take the default packet length for the device if zero is | |
44 | * specified. | |
45 | */ | |
46 | if (paclen == 0) { | |
47 | if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) | |
48 | return NULL; | |
49 | ||
50 | paclen = ax25_dev->values[AX25_VALUES_PACLEN]; | |
51 | } | |
52 | ||
53 | /* | |
54 | * Look for an existing connection. | |
55 | */ | |
56 | if ((ax25 = ax25_find_cb(src, dest, digi, dev)) != NULL) { | |
57 | ax25_output(ax25, paclen, skb); | |
58 | return ax25; /* It already existed */ | |
59 | } | |
60 | ||
61 | if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) | |
62 | return NULL; | |
63 | ||
64 | if ((ax25 = ax25_create_cb()) == NULL) | |
65 | return NULL; | |
66 | ||
67 | ax25_fillin_cb(ax25, ax25_dev); | |
68 | ||
69 | ax25->source_addr = *src; | |
70 | ax25->dest_addr = *dest; | |
71 | ||
72 | if (digi != NULL) { | |
73 | if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) { | |
74 | ax25_cb_put(ax25); | |
75 | return NULL; | |
76 | } | |
77 | memcpy(ax25->digipeat, digi, sizeof(ax25_digi)); | |
78 | } | |
79 | ||
80 | switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { | |
81 | case AX25_PROTO_STD_SIMPLEX: | |
82 | case AX25_PROTO_STD_DUPLEX: | |
83 | ax25_std_establish_data_link(ax25); | |
84 | break; | |
85 | ||
86 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
87 | case AX25_PROTO_DAMA_SLAVE: | |
88 | if (ax25_dev->dama.slave) | |
89 | ax25_ds_establish_data_link(ax25); | |
90 | else | |
91 | ax25_std_establish_data_link(ax25); | |
92 | break; | |
93 | #endif | |
94 | } | |
95 | ||
96 | ax25_cb_add(ax25); | |
97 | ||
98 | ax25->state = AX25_STATE_1; | |
99 | ||
100 | ax25_start_heartbeat(ax25); | |
101 | ||
102 | ax25_output(ax25, paclen, skb); | |
103 | ||
104 | return ax25; /* We had to create it */ | |
105 | } | |
106 | ||
70868eac RB |
107 | EXPORT_SYMBOL(ax25_send_frame); |
108 | ||
1da177e4 LT |
109 | /* |
110 | * All outgoing AX.25 I frames pass via this routine. Therefore this is | |
111 | * where the fragmentation of frames takes place. If fragment is set to | |
112 | * zero then we are not allowed to do fragmentation, even if the frame | |
113 | * is too large. | |
114 | */ | |
115 | void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb) | |
116 | { | |
117 | struct sk_buff *skbn; | |
118 | unsigned char *p; | |
119 | int frontlen, len, fragno, ka9qfrag, first = 1; | |
120 | ||
121 | if ((skb->len - 1) > paclen) { | |
122 | if (*skb->data == AX25_P_TEXT) { | |
123 | skb_pull(skb, 1); /* skip PID */ | |
124 | ka9qfrag = 0; | |
125 | } else { | |
126 | paclen -= 2; /* Allow for fragment control info */ | |
127 | ka9qfrag = 1; | |
128 | } | |
129 | ||
130 | fragno = skb->len / paclen; | |
131 | if (skb->len % paclen == 0) fragno--; | |
132 | ||
133 | frontlen = skb_headroom(skb); /* Address space + CTRL */ | |
134 | ||
135 | while (skb->len > 0) { | |
136 | spin_lock_bh(&ax25_frag_lock); | |
137 | if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) { | |
138 | spin_unlock_bh(&ax25_frag_lock); | |
139 | printk(KERN_CRIT "AX.25: ax25_output - out of memory\n"); | |
140 | return; | |
141 | } | |
142 | ||
143 | if (skb->sk != NULL) | |
144 | skb_set_owner_w(skbn, skb->sk); | |
145 | ||
146 | spin_unlock_bh(&ax25_frag_lock); | |
147 | ||
148 | len = (paclen > skb->len) ? skb->len : paclen; | |
149 | ||
150 | if (ka9qfrag == 1) { | |
151 | skb_reserve(skbn, frontlen + 2); | |
152 | skbn->nh.raw = skbn->data + (skb->nh.raw - skb->data); | |
153 | memcpy(skb_put(skbn, len), skb->data, len); | |
154 | p = skb_push(skbn, 2); | |
155 | ||
156 | *p++ = AX25_P_SEGMENT; | |
157 | ||
158 | *p = fragno--; | |
159 | if (first) { | |
160 | *p |= AX25_SEG_FIRST; | |
161 | first = 0; | |
162 | } | |
163 | } else { | |
164 | skb_reserve(skbn, frontlen + 1); | |
165 | skbn->nh.raw = skbn->data + (skb->nh.raw - skb->data); | |
166 | memcpy(skb_put(skbn, len), skb->data, len); | |
167 | p = skb_push(skbn, 1); | |
168 | *p = AX25_P_TEXT; | |
169 | } | |
170 | ||
171 | skb_pull(skb, len); | |
172 | skb_queue_tail(&ax25->write_queue, skbn); /* Throw it on the queue */ | |
173 | } | |
174 | ||
175 | kfree_skb(skb); | |
176 | } else { | |
177 | skb_queue_tail(&ax25->write_queue, skb); /* Throw it on the queue */ | |
178 | } | |
179 | ||
180 | switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { | |
181 | case AX25_PROTO_STD_SIMPLEX: | |
182 | case AX25_PROTO_STD_DUPLEX: | |
183 | ax25_kick(ax25); | |
184 | break; | |
185 | ||
186 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
187 | /* | |
188 | * A DAMA slave is _required_ to work as normal AX.25L2V2 | |
189 | * if no DAMA master is available. | |
190 | */ | |
191 | case AX25_PROTO_DAMA_SLAVE: | |
192 | if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25); | |
193 | break; | |
194 | #endif | |
195 | } | |
196 | } | |
197 | ||
198 | /* | |
199 | * This procedure is passed a buffer descriptor for an iframe. It builds | |
200 | * the rest of the control part of the frame and then writes it out. | |
201 | */ | |
202 | static void ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit) | |
203 | { | |
204 | unsigned char *frame; | |
205 | ||
206 | if (skb == NULL) | |
207 | return; | |
208 | ||
209 | skb->nh.raw = skb->data; | |
210 | ||
211 | if (ax25->modulus == AX25_MODULUS) { | |
212 | frame = skb_push(skb, 1); | |
213 | ||
214 | *frame = AX25_I; | |
215 | *frame |= (poll_bit) ? AX25_PF : 0; | |
216 | *frame |= (ax25->vr << 5); | |
217 | *frame |= (ax25->vs << 1); | |
218 | } else { | |
219 | frame = skb_push(skb, 2); | |
220 | ||
221 | frame[0] = AX25_I; | |
222 | frame[0] |= (ax25->vs << 1); | |
223 | frame[1] = (poll_bit) ? AX25_EPF : 0; | |
224 | frame[1] |= (ax25->vr << 1); | |
225 | } | |
226 | ||
227 | ax25_start_idletimer(ax25); | |
228 | ||
229 | ax25_transmit_buffer(ax25, skb, AX25_COMMAND); | |
230 | } | |
231 | ||
232 | void ax25_kick(ax25_cb *ax25) | |
233 | { | |
234 | struct sk_buff *skb, *skbn; | |
235 | int last = 1; | |
236 | unsigned short start, end, next; | |
237 | ||
238 | if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4) | |
239 | return; | |
240 | ||
241 | if (ax25->condition & AX25_COND_PEER_RX_BUSY) | |
242 | return; | |
243 | ||
244 | if (skb_peek(&ax25->write_queue) == NULL) | |
245 | return; | |
246 | ||
247 | start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs; | |
248 | end = (ax25->va + ax25->window) % ax25->modulus; | |
249 | ||
250 | if (start == end) | |
251 | return; | |
252 | ||
253 | ax25->vs = start; | |
254 | ||
255 | /* | |
256 | * Transmit data until either we're out of data to send or | |
257 | * the window is full. Send a poll on the final I frame if | |
258 | * the window is filled. | |
259 | */ | |
260 | ||
261 | /* | |
262 | * Dequeue the frame and copy it. | |
263 | */ | |
264 | skb = skb_dequeue(&ax25->write_queue); | |
265 | ||
266 | do { | |
267 | if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { | |
268 | skb_queue_head(&ax25->write_queue, skb); | |
269 | break; | |
270 | } | |
271 | ||
272 | if (skb->sk != NULL) | |
273 | skb_set_owner_w(skbn, skb->sk); | |
274 | ||
275 | next = (ax25->vs + 1) % ax25->modulus; | |
276 | last = (next == end); | |
277 | ||
278 | /* | |
279 | * Transmit the frame copy. | |
280 | * bke 960114: do not set the Poll bit on the last frame | |
281 | * in DAMA mode. | |
282 | */ | |
283 | switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { | |
284 | case AX25_PROTO_STD_SIMPLEX: | |
285 | case AX25_PROTO_STD_DUPLEX: | |
286 | ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF); | |
287 | break; | |
288 | ||
289 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
290 | case AX25_PROTO_DAMA_SLAVE: | |
291 | ax25_send_iframe(ax25, skbn, AX25_POLLOFF); | |
292 | break; | |
293 | #endif | |
294 | } | |
295 | ||
296 | ax25->vs = next; | |
297 | ||
298 | /* | |
299 | * Requeue the original data frame. | |
300 | */ | |
301 | skb_queue_tail(&ax25->ack_queue, skb); | |
302 | ||
303 | } while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL); | |
304 | ||
305 | ax25->condition &= ~AX25_COND_ACK_PENDING; | |
306 | ||
307 | if (!ax25_t1timer_running(ax25)) { | |
308 | ax25_stop_t3timer(ax25); | |
309 | ax25_calculate_t1(ax25); | |
310 | ax25_start_t1timer(ax25); | |
311 | } | |
312 | } | |
313 | ||
314 | void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type) | |
315 | { | |
316 | struct sk_buff *skbn; | |
317 | unsigned char *ptr; | |
318 | int headroom; | |
319 | ||
320 | if (ax25->ax25_dev == NULL) { | |
321 | ax25_disconnect(ax25, ENETUNREACH); | |
322 | return; | |
323 | } | |
324 | ||
325 | headroom = ax25_addr_size(ax25->digipeat); | |
326 | ||
327 | if (skb_headroom(skb) < headroom) { | |
328 | if ((skbn = skb_realloc_headroom(skb, headroom)) == NULL) { | |
329 | printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n"); | |
330 | kfree_skb(skb); | |
331 | return; | |
332 | } | |
333 | ||
334 | if (skb->sk != NULL) | |
335 | skb_set_owner_w(skbn, skb->sk); | |
336 | ||
337 | kfree_skb(skb); | |
338 | skb = skbn; | |
339 | } | |
340 | ||
341 | ptr = skb_push(skb, headroom); | |
342 | ||
343 | ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus); | |
344 | ||
29c4be51 | 345 | ax25_queue_xmit(skb, ax25->ax25_dev->dev); |
1da177e4 LT |
346 | } |
347 | ||
348 | /* | |
349 | * A small shim to dev_queue_xmit to add the KISS control byte, and do | |
350 | * any packet forwarding in operation. | |
351 | */ | |
29c4be51 | 352 | void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev) |
1da177e4 LT |
353 | { |
354 | unsigned char *ptr; | |
355 | ||
56cb5156 | 356 | skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev)); |
1da177e4 LT |
357 | |
358 | ptr = skb_push(skb, 1); | |
359 | *ptr = 0x00; /* KISS */ | |
360 | ||
361 | dev_queue_xmit(skb); | |
362 | } | |
363 | ||
364 | int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr) | |
365 | { | |
366 | if (ax25->vs == nr) { | |
367 | ax25_frames_acked(ax25, nr); | |
368 | ax25_calculate_rtt(ax25); | |
369 | ax25_stop_t1timer(ax25); | |
370 | ax25_start_t3timer(ax25); | |
371 | return 1; | |
372 | } else { | |
373 | if (ax25->va != nr) { | |
374 | ax25_frames_acked(ax25, nr); | |
375 | ax25_calculate_t1(ax25); | |
376 | ax25_start_t1timer(ax25); | |
377 | return 1; | |
378 | } | |
379 | } | |
380 | return 0; | |
381 | } | |
382 |