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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) 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 | * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de) |
11 | */ |
12 | #include <linux/errno.h> |
13 | #include <linux/types.h> |
14 | #include <linux/socket.h> |
15 | #include <linux/in.h> |
16 | #include <linux/kernel.h> |
17 | #include <linux/timer.h> |
18 | #include <linux/string.h> |
19 | #include <linux/sockios.h> |
20 | #include <linux/net.h> |
21 | #include <linux/slab.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 <net/tcp_states.h> |
29 | #include <asm/uaccess.h> |
30 | #include <linux/fcntl.h> |
31 | #include <linux/mm.h> |
32 | #include <linux/interrupt.h> |
33 | |
34 | /* |
35 | * Given a fragment, queue it on the fragment queue and if the fragment |
36 | * is complete, send it back to ax25_rx_iframe. |
37 | */ |
38 | static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb) |
39 | { |
40 | struct sk_buff *skbn, *skbo; |
41 | |
42 | if (ax25->fragno != 0) { |
43 | if (!(*skb->data & AX25_SEG_FIRST)) { |
44 | if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) { |
45 | /* Enqueue fragment */ |
46 | ax25->fragno = *skb->data & AX25_SEG_REM; |
47 | skb_pull(skb, 1); /* skip fragno */ |
48 | ax25->fraglen += skb->len; |
49 | skb_queue_tail(&ax25->frag_queue, skb); |
50 | |
51 | /* Last fragment received ? */ |
52 | if (ax25->fragno == 0) { |
53 | skbn = alloc_skb(AX25_MAX_HEADER_LEN + |
54 | ax25->fraglen, |
55 | GFP_ATOMIC); |
56 | if (!skbn) { |
57 | skb_queue_purge(&ax25->frag_queue); |
58 | return 1; |
59 | } |
60 | |
61 | skb_reserve(skbn, AX25_MAX_HEADER_LEN); |
62 | |
63 | skbn->dev = ax25->ax25_dev->dev; |
64 | skb_reset_network_header(skbn); |
65 | skb_reset_transport_header(skbn); |
66 | |
67 | /* Copy data from the fragments */ |
68 | while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) { |
69 | skb_copy_from_linear_data(skbo, |
70 | skb_put(skbn, skbo->len), |
71 | skbo->len); |
72 | kfree_skb(skbo); |
73 | } |
74 | |
75 | ax25->fraglen = 0; |
76 | |
77 | if (ax25_rx_iframe(ax25, skbn) == 0) |
78 | kfree_skb(skbn); |
79 | } |
80 | |
81 | return 1; |
82 | } |
83 | } |
84 | } else { |
85 | /* First fragment received */ |
86 | if (*skb->data & AX25_SEG_FIRST) { |
87 | skb_queue_purge(&ax25->frag_queue); |
88 | ax25->fragno = *skb->data & AX25_SEG_REM; |
89 | skb_pull(skb, 1); /* skip fragno */ |
90 | ax25->fraglen = skb->len; |
91 | skb_queue_tail(&ax25->frag_queue, skb); |
92 | return 1; |
93 | } |
94 | } |
95 | |
96 | return 0; |
97 | } |
98 | |
99 | /* |
100 | * This is where all valid I frames are sent to, to be dispatched to |
101 | * whichever protocol requires them. |
102 | */ |
103 | int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb) |
104 | { |
105 | int (*func)(struct sk_buff *, ax25_cb *); |
106 | unsigned char pid; |
107 | int queued = 0; |
108 | |
109 | if (skb == NULL) return 0; |
110 | |
111 | ax25_start_idletimer(ax25); |
112 | |
113 | pid = *skb->data; |
114 | |
115 | if (pid == AX25_P_IP) { |
116 | /* working around a TCP bug to keep additional listeners |
117 | * happy. TCP re-uses the buffer and destroys the original |
118 | * content. |
119 | */ |
120 | struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC); |
121 | if (skbn != NULL) { |
122 | kfree_skb(skb); |
123 | skb = skbn; |
124 | } |
125 | |
126 | skb_pull(skb, 1); /* Remove PID */ |
127 | skb->mac_header = skb->network_header; |
128 | skb_reset_network_header(skb); |
129 | skb->dev = ax25->ax25_dev->dev; |
130 | skb->pkt_type = PACKET_HOST; |
131 | skb->protocol = htons(ETH_P_IP); |
132 | netif_rx(skb); |
133 | return 1; |
134 | } |
135 | if (pid == AX25_P_SEGMENT) { |
136 | skb_pull(skb, 1); /* Remove PID */ |
137 | return ax25_rx_fragment(ax25, skb); |
138 | } |
139 | |
140 | if ((func = ax25_protocol_function(pid)) != NULL) { |
141 | skb_pull(skb, 1); /* Remove PID */ |
142 | return (*func)(skb, ax25); |
143 | } |
144 | |
145 | if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) { |
146 | if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) || |
147 | ax25->pidincl) { |
148 | if (sock_queue_rcv_skb(ax25->sk, skb) == 0) |
149 | queued = 1; |
150 | else |
151 | ax25->condition |= AX25_COND_OWN_RX_BUSY; |
152 | } |
153 | } |
154 | |
155 | return queued; |
156 | } |
157 | |
158 | /* |
159 | * Higher level upcall for a LAPB frame |
160 | */ |
161 | static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama) |
162 | { |
163 | int queued = 0; |
164 | |
165 | if (ax25->state == AX25_STATE_0) |
166 | return 0; |
167 | |
168 | switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { |
169 | case AX25_PROTO_STD_SIMPLEX: |
170 | case AX25_PROTO_STD_DUPLEX: |
171 | queued = ax25_std_frame_in(ax25, skb, type); |
172 | break; |
173 | |
174 | #ifdef CONFIG_AX25_DAMA_SLAVE |
175 | case AX25_PROTO_DAMA_SLAVE: |
176 | if (dama || ax25->ax25_dev->dama.slave) |
177 | queued = ax25_ds_frame_in(ax25, skb, type); |
178 | else |
179 | queued = ax25_std_frame_in(ax25, skb, type); |
180 | break; |
181 | #endif |
182 | } |
183 | |
184 | return queued; |
185 | } |
186 | |
187 | static int ax25_rcv(struct sk_buff *skb, struct net_device *dev, |
188 | ax25_address *dev_addr, struct packet_type *ptype) |
189 | { |
190 | ax25_address src, dest, *next_digi = NULL; |
191 | int type = 0, mine = 0, dama; |
192 | struct sock *make, *sk; |
193 | ax25_digi dp, reverse_dp; |
194 | ax25_cb *ax25; |
195 | ax25_dev *ax25_dev; |
196 | |
197 | /* |
198 | * Process the AX.25/LAPB frame. |
199 | */ |
200 | |
201 | skb_reset_transport_header(skb); |
202 | |
203 | if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) |
204 | goto free; |
205 | |
206 | /* |
207 | * Parse the address header. |
208 | */ |
209 | |
210 | if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) |
211 | goto free; |
212 | |
213 | /* |
214 | * Ours perhaps ? |
215 | */ |
216 | if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */ |
217 | next_digi = &dp.calls[dp.lastrepeat + 1]; |
218 | |
219 | /* |
220 | * Pull of the AX.25 headers leaving the CTRL/PID bytes |
221 | */ |
222 | skb_pull(skb, ax25_addr_size(&dp)); |
223 | |
224 | /* For our port addresses ? */ |
225 | if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi) |
226 | mine = 1; |
227 | |
228 | /* Also match on any registered callsign from L3/4 */ |
229 | if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi) |
230 | mine = 1; |
231 | |
232 | /* UI frame - bypass LAPB processing */ |
233 | if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) { |
234 | skb_set_transport_header(skb, 2); /* skip control and pid */ |
235 | |
236 | ax25_send_to_raw(&dest, skb, skb->data[1]); |
237 | |
238 | if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) |
239 | goto free; |
240 | |
241 | /* Now we are pointing at the pid byte */ |
242 | switch (skb->data[1]) { |
243 | case AX25_P_IP: |
244 | skb_pull(skb,2); /* drop PID/CTRL */ |
245 | skb_reset_transport_header(skb); |
246 | skb_reset_network_header(skb); |
247 | skb->dev = dev; |
248 | skb->pkt_type = PACKET_HOST; |
249 | skb->protocol = htons(ETH_P_IP); |
250 | netif_rx(skb); |
251 | break; |
252 | |
253 | case AX25_P_ARP: |
254 | skb_pull(skb,2); |
255 | skb_reset_transport_header(skb); |
256 | skb_reset_network_header(skb); |
257 | skb->dev = dev; |
258 | skb->pkt_type = PACKET_HOST; |
259 | skb->protocol = htons(ETH_P_ARP); |
260 | netif_rx(skb); |
261 | break; |
262 | case AX25_P_TEXT: |
263 | /* Now find a suitable dgram socket */ |
264 | sk = ax25_get_socket(&dest, &src, SOCK_DGRAM); |
265 | if (sk != NULL) { |
266 | bh_lock_sock(sk); |
267 | if (atomic_read(&sk->sk_rmem_alloc) >= |
268 | sk->sk_rcvbuf) { |
269 | kfree_skb(skb); |
270 | } else { |
271 | /* |
272 | * Remove the control and PID. |
273 | */ |
274 | skb_pull(skb, 2); |
275 | if (sock_queue_rcv_skb(sk, skb) != 0) |
276 | kfree_skb(skb); |
277 | } |
278 | bh_unlock_sock(sk); |
279 | sock_put(sk); |
280 | } else { |
281 | kfree_skb(skb); |
282 | } |
283 | break; |
284 | |
285 | default: |
286 | kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */ |
287 | break; |
288 | } |
289 | |
290 | return 0; |
291 | } |
292 | |
293 | /* |
294 | * Is connected mode supported on this device ? |
295 | * If not, should we DM the incoming frame (except DMs) or |
296 | * silently ignore them. For now we stay quiet. |
297 | */ |
298 | if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) |
299 | goto free; |
300 | |
301 | /* LAPB */ |
302 | |
303 | /* AX.25 state 1-4 */ |
304 | |
305 | ax25_digi_invert(&dp, &reverse_dp); |
306 | |
307 | if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) { |
308 | /* |
309 | * Process the frame. If it is queued up internally it |
310 | * returns one otherwise we free it immediately. This |
311 | * routine itself wakes the user context layers so we do |
312 | * no further work |
313 | */ |
314 | if (ax25_process_rx_frame(ax25, skb, type, dama) == 0) |
315 | kfree_skb(skb); |
316 | |
317 | ax25_cb_put(ax25); |
318 | return 0; |
319 | } |
320 | |
321 | /* AX.25 state 0 (disconnected) */ |
322 | |
323 | /* a) received not a SABM(E) */ |
324 | |
325 | if ((*skb->data & ~AX25_PF) != AX25_SABM && |
326 | (*skb->data & ~AX25_PF) != AX25_SABME) { |
327 | /* |
328 | * Never reply to a DM. Also ignore any connects for |
329 | * addresses that are not our interfaces and not a socket. |
330 | */ |
331 | if ((*skb->data & ~AX25_PF) != AX25_DM && mine) |
332 | ax25_return_dm(dev, &src, &dest, &dp); |
333 | |
334 | goto free; |
335 | } |
336 | |
337 | /* b) received SABM(E) */ |
338 | |
339 | if (dp.lastrepeat + 1 == dp.ndigi) |
340 | sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET); |
341 | else |
342 | sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET); |
343 | |
344 | if (sk != NULL) { |
345 | bh_lock_sock(sk); |
346 | if (sk_acceptq_is_full(sk) || |
347 | (make = ax25_make_new(sk, ax25_dev)) == NULL) { |
348 | if (mine) |
349 | ax25_return_dm(dev, &src, &dest, &dp); |
350 | kfree_skb(skb); |
351 | bh_unlock_sock(sk); |
352 | sock_put(sk); |
353 | |
354 | return 0; |
355 | } |
356 | |
357 | ax25 = ax25_sk(make); |
358 | skb_set_owner_r(skb, make); |
359 | skb_queue_head(&sk->sk_receive_queue, skb); |
360 | |
361 | make->sk_state = TCP_ESTABLISHED; |
362 | |
363 | sk->sk_ack_backlog++; |
364 | bh_unlock_sock(sk); |
365 | } else { |
366 | if (!mine) |
367 | goto free; |
368 | |
369 | if ((ax25 = ax25_create_cb()) == NULL) { |
370 | ax25_return_dm(dev, &src, &dest, &dp); |
371 | goto free; |
372 | } |
373 | |
374 | ax25_fillin_cb(ax25, ax25_dev); |
375 | } |
376 | |
377 | ax25->source_addr = dest; |
378 | ax25->dest_addr = src; |
379 | |
380 | /* |
381 | * Sort out any digipeated paths. |
382 | */ |
383 | if (dp.ndigi && !ax25->digipeat && |
384 | (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) { |
385 | kfree_skb(skb); |
386 | ax25_destroy_socket(ax25); |
387 | if (sk) |
388 | sock_put(sk); |
389 | return 0; |
390 | } |
391 | |
392 | if (dp.ndigi == 0) { |
393 | kfree(ax25->digipeat); |
394 | ax25->digipeat = NULL; |
395 | } else { |
396 | /* Reverse the source SABM's path */ |
397 | memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi)); |
398 | } |
399 | |
400 | if ((*skb->data & ~AX25_PF) == AX25_SABME) { |
401 | ax25->modulus = AX25_EMODULUS; |
402 | ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW]; |
403 | } else { |
404 | ax25->modulus = AX25_MODULUS; |
405 | ax25->window = ax25_dev->values[AX25_VALUES_WINDOW]; |
406 | } |
407 | |
408 | ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE); |
409 | |
410 | #ifdef CONFIG_AX25_DAMA_SLAVE |
411 | if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE) |
412 | ax25_dama_on(ax25); |
413 | #endif |
414 | |
415 | ax25->state = AX25_STATE_3; |
416 | |
417 | ax25_cb_add(ax25); |
418 | |
419 | ax25_start_heartbeat(ax25); |
420 | ax25_start_t3timer(ax25); |
421 | ax25_start_idletimer(ax25); |
422 | |
423 | if (sk) { |
424 | if (!sock_flag(sk, SOCK_DEAD)) |
425 | sk->sk_data_ready(sk, skb->len); |
426 | sock_put(sk); |
427 | } else { |
428 | free: |
429 | kfree_skb(skb); |
430 | } |
431 | return 0; |
432 | } |
433 | |
434 | /* |
435 | * Receive an AX.25 frame via a SLIP interface. |
436 | */ |
437 | int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev, |
438 | struct packet_type *ptype, struct net_device *orig_dev) |
439 | { |
440 | skb_orphan(skb); |
441 | |
442 | if (!net_eq(dev_net(dev), &init_net)) { |
443 | kfree_skb(skb); |
444 | return 0; |
445 | } |
446 | |
447 | if ((*skb->data & 0x0F) != 0) { |
448 | kfree_skb(skb); /* Not a KISS data frame */ |
449 | return 0; |
450 | } |
451 | |
452 | skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */ |
453 | |
454 | return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype); |
455 | } |
456 |
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Tags:
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