blob: 37507d806f65f64d6b1740dc055fea80845ff644 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/errno.h>
12#include <linux/types.h>
13#include <linux/socket.h>
14#include <linux/in.h>
15#include <linux/kernel.h>
Ralf Baechle70868ea2006-05-03 23:25:17 -070016#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/timer.h>
18#include <linux/string.h>
19#include <linux/sockios.h>
20#include <linux/spinlock.h>
21#include <linux/net.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090022#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#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
35static DEFINE_SPINLOCK(ax25_frag_lock);
36
37ax25_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) {
Arnaldo Carvalho de Melo0459d702006-11-17 12:43:07 -020073 ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC);
74 if (ax25->digipeat == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 ax25_cb_put(ax25);
76 return NULL;
77 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 }
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
Jarek Poplawskid00c3622010-01-16 01:04:04 -080096 /*
97 * There is one ref for the state machine; a caller needs
98 * one more to put it back, just like with the existing one.
99 */
100 ax25_cb_hold(ax25);
101
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 ax25_cb_add(ax25);
103
104 ax25->state = AX25_STATE_1;
105
106 ax25_start_heartbeat(ax25);
107
108 ax25_output(ax25, paclen, skb);
109
110 return ax25; /* We had to create it */
111}
112
Ralf Baechle70868ea2006-05-03 23:25:17 -0700113EXPORT_SYMBOL(ax25_send_frame);
114
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115/*
116 * All outgoing AX.25 I frames pass via this routine. Therefore this is
117 * where the fragmentation of frames takes place. If fragment is set to
118 * zero then we are not allowed to do fragmentation, even if the frame
119 * is too large.
120 */
121void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb)
122{
123 struct sk_buff *skbn;
124 unsigned char *p;
125 int frontlen, len, fragno, ka9qfrag, first = 1;
126
Jarek Poplawskif47b7252008-02-17 22:31:19 -0800127 if (paclen < 16) {
128 WARN_ON_ONCE(1);
129 kfree_skb(skb);
130 return;
131 }
132
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 if ((skb->len - 1) > paclen) {
134 if (*skb->data == AX25_P_TEXT) {
135 skb_pull(skb, 1); /* skip PID */
136 ka9qfrag = 0;
137 } else {
138 paclen -= 2; /* Allow for fragment control info */
139 ka9qfrag = 1;
140 }
141
142 fragno = skb->len / paclen;
143 if (skb->len % paclen == 0) fragno--;
144
145 frontlen = skb_headroom(skb); /* Address space + CTRL */
146
147 while (skb->len > 0) {
148 spin_lock_bh(&ax25_frag_lock);
149 if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) {
150 spin_unlock_bh(&ax25_frag_lock);
151 printk(KERN_CRIT "AX.25: ax25_output - out of memory\n");
152 return;
153 }
154
155 if (skb->sk != NULL)
156 skb_set_owner_w(skbn, skb->sk);
157
158 spin_unlock_bh(&ax25_frag_lock);
159
160 len = (paclen > skb->len) ? skb->len : paclen;
161
162 if (ka9qfrag == 1) {
163 skb_reserve(skbn, frontlen + 2);
Arnaldo Carvalho de Meloc14d2452007-03-11 22:39:41 -0300164 skb_set_network_header(skbn,
165 skb_network_offset(skb));
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -0300166 skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 p = skb_push(skbn, 2);
168
169 *p++ = AX25_P_SEGMENT;
170
171 *p = fragno--;
172 if (first) {
173 *p |= AX25_SEG_FIRST;
174 first = 0;
175 }
176 } else {
177 skb_reserve(skbn, frontlen + 1);
Arnaldo Carvalho de Meloc14d2452007-03-11 22:39:41 -0300178 skb_set_network_header(skbn,
179 skb_network_offset(skb));
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -0300180 skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 p = skb_push(skbn, 1);
182 *p = AX25_P_TEXT;
183 }
184
185 skb_pull(skb, len);
186 skb_queue_tail(&ax25->write_queue, skbn); /* Throw it on the queue */
187 }
188
189 kfree_skb(skb);
190 } else {
191 skb_queue_tail(&ax25->write_queue, skb); /* Throw it on the queue */
192 }
193
194 switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
195 case AX25_PROTO_STD_SIMPLEX:
196 case AX25_PROTO_STD_DUPLEX:
197 ax25_kick(ax25);
198 break;
199
200#ifdef CONFIG_AX25_DAMA_SLAVE
201 /*
202 * A DAMA slave is _required_ to work as normal AX.25L2V2
203 * if no DAMA master is available.
204 */
205 case AX25_PROTO_DAMA_SLAVE:
206 if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25);
207 break;
208#endif
209 }
210}
211
212/*
213 * This procedure is passed a buffer descriptor for an iframe. It builds
214 * the rest of the control part of the frame and then writes it out.
215 */
216static void ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit)
217{
218 unsigned char *frame;
219
220 if (skb == NULL)
221 return;
222
Arnaldo Carvalho de Meloc1d2bbe2007-04-10 20:45:18 -0700223 skb_reset_network_header(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
225 if (ax25->modulus == AX25_MODULUS) {
226 frame = skb_push(skb, 1);
227
228 *frame = AX25_I;
229 *frame |= (poll_bit) ? AX25_PF : 0;
230 *frame |= (ax25->vr << 5);
231 *frame |= (ax25->vs << 1);
232 } else {
233 frame = skb_push(skb, 2);
234
235 frame[0] = AX25_I;
236 frame[0] |= (ax25->vs << 1);
237 frame[1] = (poll_bit) ? AX25_EPF : 0;
238 frame[1] |= (ax25->vr << 1);
239 }
240
241 ax25_start_idletimer(ax25);
242
243 ax25_transmit_buffer(ax25, skb, AX25_COMMAND);
244}
245
246void ax25_kick(ax25_cb *ax25)
247{
248 struct sk_buff *skb, *skbn;
249 int last = 1;
250 unsigned short start, end, next;
251
252 if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4)
253 return;
254
255 if (ax25->condition & AX25_COND_PEER_RX_BUSY)
256 return;
257
258 if (skb_peek(&ax25->write_queue) == NULL)
259 return;
260
261 start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs;
262 end = (ax25->va + ax25->window) % ax25->modulus;
263
264 if (start == end)
265 return;
266
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 /*
268 * Transmit data until either we're out of data to send or
269 * the window is full. Send a poll on the final I frame if
270 * the window is filled.
271 */
272
273 /*
274 * Dequeue the frame and copy it.
Jarek Poplawskif47b7252008-02-17 22:31:19 -0800275 * Check for race with ax25_clear_queues().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 */
277 skb = skb_dequeue(&ax25->write_queue);
Jarek Poplawskif47b7252008-02-17 22:31:19 -0800278 if (!skb)
279 return;
280
281 ax25->vs = start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
283 do {
284 if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
285 skb_queue_head(&ax25->write_queue, skb);
286 break;
287 }
288
289 if (skb->sk != NULL)
290 skb_set_owner_w(skbn, skb->sk);
291
292 next = (ax25->vs + 1) % ax25->modulus;
293 last = (next == end);
294
295 /*
296 * Transmit the frame copy.
297 * bke 960114: do not set the Poll bit on the last frame
298 * in DAMA mode.
299 */
300 switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
301 case AX25_PROTO_STD_SIMPLEX:
302 case AX25_PROTO_STD_DUPLEX:
303 ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF);
304 break;
305
306#ifdef CONFIG_AX25_DAMA_SLAVE
307 case AX25_PROTO_DAMA_SLAVE:
308 ax25_send_iframe(ax25, skbn, AX25_POLLOFF);
309 break;
310#endif
311 }
312
313 ax25->vs = next;
314
315 /*
316 * Requeue the original data frame.
317 */
318 skb_queue_tail(&ax25->ack_queue, skb);
319
320 } while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL);
321
322 ax25->condition &= ~AX25_COND_ACK_PENDING;
323
324 if (!ax25_t1timer_running(ax25)) {
325 ax25_stop_t3timer(ax25);
326 ax25_calculate_t1(ax25);
327 ax25_start_t1timer(ax25);
328 }
329}
330
331void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type)
332{
333 struct sk_buff *skbn;
334 unsigned char *ptr;
335 int headroom;
336
337 if (ax25->ax25_dev == NULL) {
338 ax25_disconnect(ax25, ENETUNREACH);
339 return;
340 }
341
342 headroom = ax25_addr_size(ax25->digipeat);
343
344 if (skb_headroom(skb) < headroom) {
345 if ((skbn = skb_realloc_headroom(skb, headroom)) == NULL) {
346 printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n");
347 kfree_skb(skb);
348 return;
349 }
350
351 if (skb->sk != NULL)
352 skb_set_owner_w(skbn, skb->sk);
353
354 kfree_skb(skb);
355 skb = skbn;
356 }
357
358 ptr = skb_push(skb, headroom);
359
360 ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus);
361
Arnaldo Carvalho de Melo29c4be52005-04-21 16:46:56 -0700362 ax25_queue_xmit(skb, ax25->ax25_dev->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363}
364
365/*
366 * A small shim to dev_queue_xmit to add the KISS control byte, and do
367 * any packet forwarding in operation.
368 */
Arnaldo Carvalho de Melo29c4be52005-04-21 16:46:56 -0700369void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370{
371 unsigned char *ptr;
372
Arnaldo Carvalho de Melo56cb5152005-04-24 18:53:06 -0700373 skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374
375 ptr = skb_push(skb, 1);
376 *ptr = 0x00; /* KISS */
377
378 dev_queue_xmit(skb);
379}
380
381int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr)
382{
383 if (ax25->vs == nr) {
384 ax25_frames_acked(ax25, nr);
385 ax25_calculate_rtt(ax25);
386 ax25_stop_t1timer(ax25);
387 ax25_start_t3timer(ax25);
388 return 1;
389 } else {
390 if (ax25->va != nr) {
391 ax25_frames_acked(ax25, nr);
392 ax25_calculate_t1(ax25);
393 ax25_start_t1timer(ax25);
394 return 1;
395 }
396 }
397 return 0;
398}
399