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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [net/] [ax25/] [ax25_out.c] - Blame information for rev 17

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Line No. Rev Author Line
1 3 xianfeng 
/*
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 <net/ax25.h>
23 
#include <linux/inet.h>
24 
#include <linux/netdevice.h>
25 
#include <linux/skbuff.h>
26 
#include <linux/netfilter.h>
27 
#include <net/sock.h>
28 
#include <asm/uaccess.h>
29 
#include <asm/system.h>
30 
#include <linux/fcntl.h>
31 
#include <linux/mm.h>
32 
#include <linux/interrupt.h>
33 
 
34 
static DEFINE_SPINLOCK(ax25_frag_lock);
35 
 
36 
ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, ax25_address *src, ax25_address *dest, ax25_digi *digi, struct net_device *dev)
37 
{
38 
        ax25_dev *ax25_dev;
39 
        ax25_cb *ax25;
40 
 
41 
        /*
42 
         * Take the default packet length for the device if zero is
43 
         * specified.
44 
         */
45 
        if (paclen == 0) {
46 
                if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
47 
                        return NULL;
48 
 
49 
                paclen = ax25_dev->values[AX25_VALUES_PACLEN];
50 
        }
51 
 
52 
        /*
53 
         * Look for an existing connection.
54 
         */
55 
        if ((ax25 = ax25_find_cb(src, dest, digi, dev)) != NULL) {
56 
                ax25_output(ax25, paclen, skb);
57 
                return ax25;            /* It already existed */
58 
        }
59 
 
60 
        if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
61 
                return NULL;
62 
 
63 
        if ((ax25 = ax25_create_cb()) == NULL)
64 
                return NULL;
65 
 
66 
        ax25_fillin_cb(ax25, ax25_dev);
67 
 
68 
        ax25->source_addr = *src;
69 
        ax25->dest_addr   = *dest;
70 
 
71 
        if (digi != NULL) {
72 
                ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC);
73 
                if (ax25->digipeat == NULL) {
74 
                        ax25_cb_put(ax25);
75 
                        return NULL;
76 
                }
77 
        }
78 
 
79 
        switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
80 
        case AX25_PROTO_STD_SIMPLEX:
81 
        case AX25_PROTO_STD_DUPLEX:
82 
                ax25_std_establish_data_link(ax25);
83 
                break;
84 
 
85 
#ifdef CONFIG_AX25_DAMA_SLAVE
86 
        case AX25_PROTO_DAMA_SLAVE:
87 
                if (ax25_dev->dama.slave)
88 
                        ax25_ds_establish_data_link(ax25);
89 
                else
90 
                        ax25_std_establish_data_link(ax25);
91 
                break;
92 
#endif
93 
        }
94 
 
95 
        ax25_cb_add(ax25);
96 
 
97 
        ax25->state = AX25_STATE_1;
98 
 
99 
        ax25_start_heartbeat(ax25);
100 
 
101 
        ax25_output(ax25, paclen, skb);
102 
 
103 
        return ax25;                    /* We had to create it */
104 
}
105 
 
106 
EXPORT_SYMBOL(ax25_send_frame);
107 
 
108 
/*
109 
 *      All outgoing AX.25 I frames pass via this routine. Therefore this is
110 
 *      where the fragmentation of frames takes place. If fragment is set to
111 
 *      zero then we are not allowed to do fragmentation, even if the frame
112 
 *      is too large.
113 
 */
114 
void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb)
115 
{
116 
        struct sk_buff *skbn;
117 
        unsigned char *p;
118 
        int frontlen, len, fragno, ka9qfrag, first = 1;
119 
 
120 
        if ((skb->len - 1) > paclen) {
121 
                if (*skb->data == AX25_P_TEXT) {
122 
                        skb_pull(skb, 1); /* skip PID */
123 
                        ka9qfrag = 0;
124 
                } else {
125 
                        paclen -= 2;    /* Allow for fragment control info */
126 
                        ka9qfrag = 1;
127 
                }
128 
 
129 
                fragno = skb->len / paclen;
130 
                if (skb->len % paclen == 0) fragno--;
131 
 
132 
                frontlen = skb_headroom(skb);   /* Address space + CTRL */
133 
 
134 
                while (skb->len > 0) {
135 
                        spin_lock_bh(&ax25_frag_lock);
136 
                        if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) {
137 
                                spin_unlock_bh(&ax25_frag_lock);
138 
                                printk(KERN_CRIT "AX.25: ax25_output - out of memory\n");
139 
                                return;
140 
                        }
141 
 
142 
                        if (skb->sk != NULL)
143 
                                skb_set_owner_w(skbn, skb->sk);
144 
 
145 
                        spin_unlock_bh(&ax25_frag_lock);
146 
 
147 
                        len = (paclen > skb->len) ? skb->len : paclen;
148 
 
149 
                        if (ka9qfrag == 1) {
150 
                                skb_reserve(skbn, frontlen + 2);
151 
                                skb_set_network_header(skbn,
152 
                                                      skb_network_offset(skb));
153 
                                skb_copy_from_linear_data(skb, skb_put(skbn, len), 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 
                                skb_set_network_header(skbn,
166 
                                                      skb_network_offset(skb));
167 
                                skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
168 
                                p = skb_push(skbn, 1);
169 
                                *p = AX25_P_TEXT;
170 
                        }
171 
 
172 
                        skb_pull(skb, len);
173 
                        skb_queue_tail(&ax25->write_queue, skbn); /* Throw it on the queue */
174 
                }
175 
 
176 
                kfree_skb(skb);
177 
        } else {
178 
                skb_queue_tail(&ax25->write_queue, skb);          /* Throw it on the queue */
179 
        }
180 
 
181 
        switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
182 
        case AX25_PROTO_STD_SIMPLEX:
183 
        case AX25_PROTO_STD_DUPLEX:
184 
                ax25_kick(ax25);
185 
                break;
186 
 
187 
#ifdef CONFIG_AX25_DAMA_SLAVE
188 
        /*
189 
         * A DAMA slave is _required_ to work as normal AX.25L2V2
190 
         * if no DAMA master is available.
191 
         */
192 
        case AX25_PROTO_DAMA_SLAVE:
193 
                if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25);
194 
                break;
195 
#endif
196 
        }
197 
}
198 
 
199 
/*
200 
 *  This procedure is passed a buffer descriptor for an iframe. It builds
201 
 *  the rest of the control part of the frame and then writes it out.
202 
 */
203 
static void ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit)
204 
{
205 
        unsigned char *frame;
206 
 
207 
        if (skb == NULL)
208 
                return;
209 
 
210 
        skb_reset_network_header(skb);
211 
 
212 
        if (ax25->modulus == AX25_MODULUS) {
213 
                frame = skb_push(skb, 1);
214 
 
215 
                *frame = AX25_I;
216 
                *frame |= (poll_bit) ? AX25_PF : 0;
217 
                *frame |= (ax25->vr << 5);
218 
                *frame |= (ax25->vs << 1);
219 
        } else {
220 
                frame = skb_push(skb, 2);
221 
 
222 
                frame[0] = AX25_I;
223 
                frame[0] |= (ax25->vs << 1);
224 
                frame[1] = (poll_bit) ? AX25_EPF : 0;
225 
                frame[1] |= (ax25->vr << 1);
226 
        }
227 
 
228 
        ax25_start_idletimer(ax25);
229 
 
230 
        ax25_transmit_buffer(ax25, skb, AX25_COMMAND);
231 
}
232 
 
233 
void ax25_kick(ax25_cb *ax25)
234 
{
235 
        struct sk_buff *skb, *skbn;
236 
        int last = 1;
237 
        unsigned short start, end, next;
238 
 
239 
        if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4)
240 
                return;
241 
 
242 
        if (ax25->condition & AX25_COND_PEER_RX_BUSY)
243 
                return;
244 
 
245 
        if (skb_peek(&ax25->write_queue) == NULL)
246 
                return;
247 
 
248 
        start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs;
249 
        end   = (ax25->va + ax25->window) % ax25->modulus;
250 
 
251 
        if (start == end)
252 
                return;
253 
 
254 
        ax25->vs = start;
255 
 
256 
        /*
257 
         * Transmit data until either we're out of data to send or
258 
         * the window is full. Send a poll on the final I frame if
259 
         * the window is filled.
260 
         */
261 
 
262 
        /*
263 
         * Dequeue the frame and copy it.
264 
         */
265 
        skb  = skb_dequeue(&ax25->write_queue);
266 
 
267 
        do {
268 
                if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
269 
                        skb_queue_head(&ax25->write_queue, skb);
270 
                        break;
271 
                }
272 
 
273 
                if (skb->sk != NULL)
274 
                        skb_set_owner_w(skbn, skb->sk);
275 
 
276 
                next = (ax25->vs + 1) % ax25->modulus;
277 
                last = (next == end);
278 
 
279 
                /*
280 
                 * Transmit the frame copy.
281 
                 * bke 960114: do not set the Poll bit on the last frame
282 
                 * in DAMA mode.
283 
                 */
284 
                switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
285 
                case AX25_PROTO_STD_SIMPLEX:
286 
                case AX25_PROTO_STD_DUPLEX:
287 
                        ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF);
288 
                        break;
289 
 
290 
#ifdef CONFIG_AX25_DAMA_SLAVE
291 
                case AX25_PROTO_DAMA_SLAVE:
292 
                        ax25_send_iframe(ax25, skbn, AX25_POLLOFF);
293 
                        break;
294 
#endif
295 
                }
296 
 
297 
                ax25->vs = next;
298 
 
299 
                /*
300 
                 * Requeue the original data frame.
301 
                 */
302 
                skb_queue_tail(&ax25->ack_queue, skb);
303 
 
304 
        } while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL);
305 
 
306 
        ax25->condition &= ~AX25_COND_ACK_PENDING;
307 
 
308 
        if (!ax25_t1timer_running(ax25)) {
309 
                ax25_stop_t3timer(ax25);
310 
                ax25_calculate_t1(ax25);
311 
                ax25_start_t1timer(ax25);
312 
        }
313 
}
314 
 
315 
void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type)
316 
{
317 
        struct sk_buff *skbn;
318 
        unsigned char *ptr;
319 
        int headroom;
320 
 
321 
        if (ax25->ax25_dev == NULL) {
322 
                ax25_disconnect(ax25, ENETUNREACH);
323 
                return;
324 
        }
325 
 
326 
        headroom = ax25_addr_size(ax25->digipeat);
327 
 
328 
        if (skb_headroom(skb) < headroom) {
329 
                if ((skbn = skb_realloc_headroom(skb, headroom)) == NULL) {
330 
                        printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n");
331 
                        kfree_skb(skb);
332 
                        return;
333 
                }
334 
 
335 
                if (skb->sk != NULL)
336 
                        skb_set_owner_w(skbn, skb->sk);
337 
 
338 
                kfree_skb(skb);
339 
                skb = skbn;
340 
        }
341 
 
342 
        ptr = skb_push(skb, headroom);
343 
 
344 
        ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus);
345 
 
346 
        ax25_queue_xmit(skb, ax25->ax25_dev->dev);
347 
}
348 
 
349 
/*
350 
 *      A small shim to dev_queue_xmit to add the KISS control byte, and do
351 
 *      any packet forwarding in operation.
352 
 */
353 
void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev)
354 
{
355 
        unsigned char *ptr;
356 
 
357 
        skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev));
358 
 
359 
        ptr  = skb_push(skb, 1);
360 
        *ptr = 0x00;                    /* KISS */
361 
 
362 
        dev_queue_xmit(skb);
363 
}
364 
 
365 
int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr)
366 
{
367 
        if (ax25->vs == nr) {
368 
                ax25_frames_acked(ax25, nr);
369 
                ax25_calculate_rtt(ax25);
370 
                ax25_stop_t1timer(ax25);
371 
                ax25_start_t3timer(ax25);
372 
                return 1;
373 
        } else {
374 
                if (ax25->va != nr) {
375 
                        ax25_frames_acked(ax25, nr);
376 
                        ax25_calculate_t1(ax25);
377 
                        ax25_start_t1timer(ax25);
378 
                        return 1;
379 
                }
380 
        }
381 
        return 0;
382 
}
383 
 

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