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v3.1
 
  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 */
 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>
 16#include <linux/module.h>
 17#include <linux/timer.h>
 18#include <linux/string.h>
 19#include <linux/sockios.h>
 20#include <linux/spinlock.h>
 21#include <linux/net.h>
 22#include <linux/slab.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
 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) {
 73		ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC);
 74		if (ax25->digipeat == NULL) {
 75			ax25_cb_put(ax25);
 76			return NULL;
 77		}
 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	/*
 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
102	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
113EXPORT_SYMBOL(ax25_send_frame);
114
115/*
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
127	if (paclen < 16) {
128		WARN_ON_ONCE(1);
129		kfree_skb(skb);
130		return;
131	}
132
133	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);
164				skb_set_network_header(skbn,
165						      skb_network_offset(skb));
166				skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
167				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);
178				skb_set_network_header(skbn,
179						      skb_network_offset(skb));
180				skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
181				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
223	skb_reset_network_header(skb);
224
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
267	/*
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.
275	 * Check for race with ax25_clear_queues().
276	 */
277	skb  = skb_dequeue(&ax25->write_queue);
278	if (!skb)
279		return;
280
281	ax25->vs = start;
282
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
362	ax25_queue_xmit(skb, ax25->ax25_dev->dev);
363}
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 */
369void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev)
370{
371	unsigned char *ptr;
372
373	skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev));
374
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
v6.9.4
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
 
 
 
 
  3 *
  4 * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
  5 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
  6 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
  7 */
  8#include <linux/errno.h>
  9#include <linux/types.h>
 10#include <linux/socket.h>
 11#include <linux/in.h>
 12#include <linux/kernel.h>
 13#include <linux/module.h>
 14#include <linux/timer.h>
 15#include <linux/string.h>
 16#include <linux/sockios.h>
 17#include <linux/spinlock.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/uaccess.h>
 
 26#include <linux/fcntl.h>
 27#include <linux/mm.h>
 28#include <linux/interrupt.h>
 29
 30static DEFINE_SPINLOCK(ax25_frag_lock);
 31
 32ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, const ax25_address *src, ax25_address *dest, ax25_digi *digi, struct net_device *dev)
 33{
 34	ax25_dev *ax25_dev;
 35	ax25_cb *ax25;
 36
 37	/*
 38	 * Take the default packet length for the device if zero is
 39	 * specified.
 40	 */
 41	if (paclen == 0) {
 42		if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
 43			return NULL;
 44
 45		paclen = ax25_dev->values[AX25_VALUES_PACLEN];
 46	}
 47
 48	/*
 49	 * Look for an existing connection.
 50	 */
 51	if ((ax25 = ax25_find_cb(src, dest, digi, dev)) != NULL) {
 52		ax25_output(ax25, paclen, skb);
 53		return ax25;		/* It already existed */
 54	}
 55
 56	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
 57		return NULL;
 58
 59	if ((ax25 = ax25_create_cb()) == NULL)
 60		return NULL;
 61
 62	ax25_fillin_cb(ax25, ax25_dev);
 63
 64	ax25->source_addr = *src;
 65	ax25->dest_addr   = *dest;
 66
 67	if (digi != NULL) {
 68		ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC);
 69		if (ax25->digipeat == NULL) {
 70			ax25_cb_put(ax25);
 71			return NULL;
 72		}
 73	}
 74
 75	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
 76	case AX25_PROTO_STD_SIMPLEX:
 77	case AX25_PROTO_STD_DUPLEX:
 78		ax25_std_establish_data_link(ax25);
 79		break;
 80
 81#ifdef CONFIG_AX25_DAMA_SLAVE
 82	case AX25_PROTO_DAMA_SLAVE:
 83		if (ax25_dev->dama.slave)
 84			ax25_ds_establish_data_link(ax25);
 85		else
 86			ax25_std_establish_data_link(ax25);
 87		break;
 88#endif
 89	}
 90
 91	/*
 92	 * There is one ref for the state machine; a caller needs
 93	 * one more to put it back, just like with the existing one.
 94	 */
 95	ax25_cb_hold(ax25);
 96
 97	ax25_cb_add(ax25);
 98
 99	ax25->state = AX25_STATE_1;
100
101	ax25_start_heartbeat(ax25);
102
103	ax25_output(ax25, paclen, skb);
104
105	return ax25;			/* We had to create it */
106}
107
108EXPORT_SYMBOL(ax25_send_frame);
109
110/*
111 *	All outgoing AX.25 I frames pass via this routine. Therefore this is
112 *	where the fragmentation of frames takes place. If fragment is set to
113 *	zero then we are not allowed to do fragmentation, even if the frame
114 *	is too large.
115 */
116void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb)
117{
118	struct sk_buff *skbn;
119	unsigned char *p;
120	int frontlen, len, fragno, ka9qfrag, first = 1;
121
122	if (paclen < 16) {
123		WARN_ON_ONCE(1);
124		kfree_skb(skb);
125		return;
126	}
127
128	if ((skb->len - 1) > paclen) {
129		if (*skb->data == AX25_P_TEXT) {
130			skb_pull(skb, 1); /* skip PID */
131			ka9qfrag = 0;
132		} else {
133			paclen -= 2;	/* Allow for fragment control info */
134			ka9qfrag = 1;
135		}
136
137		fragno = skb->len / paclen;
138		if (skb->len % paclen == 0) fragno--;
139
140		frontlen = skb_headroom(skb);	/* Address space + CTRL */
141
142		while (skb->len > 0) {
143			spin_lock_bh(&ax25_frag_lock);
144			if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) {
145				spin_unlock_bh(&ax25_frag_lock);
146				printk(KERN_CRIT "AX.25: ax25_output - out of memory\n");
147				return;
148			}
149
150			if (skb->sk != NULL)
151				skb_set_owner_w(skbn, skb->sk);
152
153			spin_unlock_bh(&ax25_frag_lock);
154
155			len = (paclen > skb->len) ? skb->len : paclen;
156
157			if (ka9qfrag == 1) {
158				skb_reserve(skbn, frontlen + 2);
159				skb_set_network_header(skbn,
160						      skb_network_offset(skb));
161				skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
162				p = skb_push(skbn, 2);
163
164				*p++ = AX25_P_SEGMENT;
165
166				*p = fragno--;
167				if (first) {
168					*p |= AX25_SEG_FIRST;
169					first = 0;
170				}
171			} else {
172				skb_reserve(skbn, frontlen + 1);
173				skb_set_network_header(skbn,
174						      skb_network_offset(skb));
175				skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
176				p = skb_push(skbn, 1);
177				*p = AX25_P_TEXT;
178			}
179
180			skb_pull(skb, len);
181			skb_queue_tail(&ax25->write_queue, skbn); /* Throw it on the queue */
182		}
183
184		kfree_skb(skb);
185	} else {
186		skb_queue_tail(&ax25->write_queue, skb);	  /* Throw it on the queue */
187	}
188
189	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
190	case AX25_PROTO_STD_SIMPLEX:
191	case AX25_PROTO_STD_DUPLEX:
192		ax25_kick(ax25);
193		break;
194
195#ifdef CONFIG_AX25_DAMA_SLAVE
196	/*
197	 * A DAMA slave is _required_ to work as normal AX.25L2V2
198	 * if no DAMA master is available.
199	 */
200	case AX25_PROTO_DAMA_SLAVE:
201		if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25);
202		break;
203#endif
204	}
205}
206
207/*
208 *  This procedure is passed a buffer descriptor for an iframe. It builds
209 *  the rest of the control part of the frame and then writes it out.
210 */
211static void ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit)
212{
213	unsigned char *frame;
214
215	if (skb == NULL)
216		return;
217
218	skb_reset_network_header(skb);
219
220	if (ax25->modulus == AX25_MODULUS) {
221		frame = skb_push(skb, 1);
222
223		*frame = AX25_I;
224		*frame |= (poll_bit) ? AX25_PF : 0;
225		*frame |= (ax25->vr << 5);
226		*frame |= (ax25->vs << 1);
227	} else {
228		frame = skb_push(skb, 2);
229
230		frame[0] = AX25_I;
231		frame[0] |= (ax25->vs << 1);
232		frame[1] = (poll_bit) ? AX25_EPF : 0;
233		frame[1] |= (ax25->vr << 1);
234	}
235
236	ax25_start_idletimer(ax25);
237
238	ax25_transmit_buffer(ax25, skb, AX25_COMMAND);
239}
240
241void ax25_kick(ax25_cb *ax25)
242{
243	struct sk_buff *skb, *skbn;
244	int last = 1;
245	unsigned short start, end, next;
246
247	if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4)
248		return;
249
250	if (ax25->condition & AX25_COND_PEER_RX_BUSY)
251		return;
252
253	if (skb_peek(&ax25->write_queue) == NULL)
254		return;
255
256	start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs;
257	end   = (ax25->va + ax25->window) % ax25->modulus;
258
259	if (start == end)
260		return;
261
262	/*
263	 * Transmit data until either we're out of data to send or
264	 * the window is full. Send a poll on the final I frame if
265	 * the window is filled.
266	 */
267
268	/*
269	 * Dequeue the frame and copy it.
270	 * Check for race with ax25_clear_queues().
271	 */
272	skb  = skb_dequeue(&ax25->write_queue);
273	if (!skb)
274		return;
275
276	ax25->vs = start;
277
278	do {
279		if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
280			skb_queue_head(&ax25->write_queue, skb);
281			break;
282		}
283
284		if (skb->sk != NULL)
285			skb_set_owner_w(skbn, skb->sk);
286
287		next = (ax25->vs + 1) % ax25->modulus;
288		last = (next == end);
289
290		/*
291		 * Transmit the frame copy.
292		 * bke 960114: do not set the Poll bit on the last frame
293		 * in DAMA mode.
294		 */
295		switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
296		case AX25_PROTO_STD_SIMPLEX:
297		case AX25_PROTO_STD_DUPLEX:
298			ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF);
299			break;
300
301#ifdef CONFIG_AX25_DAMA_SLAVE
302		case AX25_PROTO_DAMA_SLAVE:
303			ax25_send_iframe(ax25, skbn, AX25_POLLOFF);
304			break;
305#endif
306		}
307
308		ax25->vs = next;
309
310		/*
311		 * Requeue the original data frame.
312		 */
313		skb_queue_tail(&ax25->ack_queue, skb);
314
315	} while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL);
316
317	ax25->condition &= ~AX25_COND_ACK_PENDING;
318
319	if (!ax25_t1timer_running(ax25)) {
320		ax25_stop_t3timer(ax25);
321		ax25_calculate_t1(ax25);
322		ax25_start_t1timer(ax25);
323	}
324}
325
326void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type)
327{
 
328	unsigned char *ptr;
329	int headroom;
330
331	if (ax25->ax25_dev == NULL) {
332		ax25_disconnect(ax25, ENETUNREACH);
333		return;
334	}
335
336	headroom = ax25_addr_size(ax25->digipeat);
337
338	if (unlikely(skb_headroom(skb) < headroom)) {
339		skb = skb_expand_head(skb, headroom);
340		if (!skb) {
341			printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n");
 
342			return;
343		}
 
 
 
 
 
 
344	}
345
346	ptr = skb_push(skb, headroom);
347
348	ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus);
349
350	ax25_queue_xmit(skb, ax25->ax25_dev->dev);
351}
352
353/*
354 *	A small shim to dev_queue_xmit to add the KISS control byte, and do
355 *	any packet forwarding in operation.
356 */
357void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev)
358{
359	unsigned char *ptr;
360
361	skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev));
362
363	ptr  = skb_push(skb, 1);
364	*ptr = 0x00;			/* KISS */
365
366	dev_queue_xmit(skb);
367}
368
369int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr)
370{
371	if (ax25->vs == nr) {
372		ax25_frames_acked(ax25, nr);
373		ax25_calculate_rtt(ax25);
374		ax25_stop_t1timer(ax25);
375		ax25_start_t3timer(ax25);
376		return 1;
377	} else {
378		if (ax25->va != nr) {
379			ax25_frames_acked(ax25, nr);
380			ax25_calculate_t1(ax25);
381			ax25_start_t1timer(ax25);
382			return 1;
383		}
384	}
385	return 0;
386}