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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 | * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de) | |
11 | */ | |
1da177e4 LT |
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/sched.h> | |
18 | #include <linux/timer.h> | |
19 | #include <linux/string.h> | |
20 | #include <linux/sockios.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> | |
c752f073 | 28 | #include <net/tcp_states.h> |
1da177e4 LT |
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 | /* | |
36 | * Given a fragment, queue it on the fragment queue and if the fragment | |
37 | * is complete, send it back to ax25_rx_iframe. | |
38 | */ | |
39 | static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb) | |
40 | { | |
41 | struct sk_buff *skbn, *skbo; | |
42 | ||
43 | if (ax25->fragno != 0) { | |
44 | if (!(*skb->data & AX25_SEG_FIRST)) { | |
45 | if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) { | |
46 | /* Enqueue fragment */ | |
47 | ax25->fragno = *skb->data & AX25_SEG_REM; | |
48 | skb_pull(skb, 1); /* skip fragno */ | |
49 | ax25->fraglen += skb->len; | |
50 | skb_queue_tail(&ax25->frag_queue, skb); | |
51 | ||
52 | /* Last fragment received ? */ | |
53 | if (ax25->fragno == 0) { | |
54 | skbn = alloc_skb(AX25_MAX_HEADER_LEN + | |
55 | ax25->fraglen, | |
56 | GFP_ATOMIC); | |
57 | if (!skbn) { | |
58 | skb_queue_purge(&ax25->frag_queue); | |
59 | return 1; | |
60 | } | |
61 | ||
62 | skb_reserve(skbn, AX25_MAX_HEADER_LEN); | |
63 | ||
64 | skbn->dev = ax25->ax25_dev->dev; | |
65 | skbn->h.raw = skbn->data; | |
66 | skbn->nh.raw = skbn->data; | |
67 | ||
68 | /* Copy data from the fragments */ | |
69 | while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) { | |
70 | memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len); | |
71 | kfree_skb(skbo); | |
72 | } | |
73 | ||
74 | ax25->fraglen = 0; | |
75 | ||
76 | if (ax25_rx_iframe(ax25, skbn) == 0) | |
77 | kfree_skb(skbn); | |
78 | } | |
79 | ||
80 | return 1; | |
81 | } | |
82 | } | |
83 | } else { | |
84 | /* First fragment received */ | |
85 | if (*skb->data & AX25_SEG_FIRST) { | |
86 | skb_queue_purge(&ax25->frag_queue); | |
87 | ax25->fragno = *skb->data & AX25_SEG_REM; | |
88 | skb_pull(skb, 1); /* skip fragno */ | |
89 | ax25->fraglen = skb->len; | |
90 | skb_queue_tail(&ax25->frag_queue, skb); | |
91 | return 1; | |
92 | } | |
93 | } | |
94 | ||
95 | return 0; | |
96 | } | |
97 | ||
98 | /* | |
99 | * This is where all valid I frames are sent to, to be dispatched to | |
100 | * whichever protocol requires them. | |
101 | */ | |
102 | int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb) | |
103 | { | |
104 | int (*func)(struct sk_buff *, ax25_cb *); | |
1da177e4 | 105 | unsigned char pid; |
bde3445c | 106 | int queued = 0; |
1da177e4 LT |
107 | |
108 | if (skb == NULL) return 0; | |
109 | ||
110 | ax25_start_idletimer(ax25); | |
111 | ||
112 | pid = *skb->data; | |
113 | ||
1da177e4 LT |
114 | if (pid == AX25_P_IP) { |
115 | /* working around a TCP bug to keep additional listeners | |
116 | * happy. TCP re-uses the buffer and destroys the original | |
117 | * content. | |
118 | */ | |
119 | struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC); | |
120 | if (skbn != NULL) { | |
121 | kfree_skb(skb); | |
122 | skb = skbn; | |
123 | } | |
124 | ||
125 | skb_pull(skb, 1); /* Remove PID */ | |
3a867b36 | 126 | skb->mac.raw = skb->nh.raw; |
1da177e4 LT |
127 | skb->nh.raw = skb->data; |
128 | skb->dev = ax25->ax25_dev->dev; | |
129 | skb->pkt_type = PACKET_HOST; | |
130 | skb->protocol = htons(ETH_P_IP); | |
98a82feb | 131 | netif_rx(skb); |
1da177e4 LT |
132 | return 1; |
133 | } | |
1da177e4 LT |
134 | if (pid == AX25_P_SEGMENT) { |
135 | skb_pull(skb, 1); /* Remove PID */ | |
136 | return ax25_rx_fragment(ax25, skb); | |
137 | } | |
138 | ||
139 | if ((func = ax25_protocol_function(pid)) != NULL) { | |
140 | skb_pull(skb, 1); /* Remove PID */ | |
141 | return (*func)(skb, ax25); | |
142 | } | |
143 | ||
144 | if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) { | |
145 | if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) || | |
146 | ax25->pidincl) { | |
147 | if (sock_queue_rcv_skb(ax25->sk, skb) == 0) | |
148 | queued = 1; | |
149 | else | |
150 | ax25->condition |= AX25_COND_OWN_RX_BUSY; | |
151 | } | |
152 | } | |
153 | ||
154 | return queued; | |
155 | } | |
156 | ||
157 | /* | |
158 | * Higher level upcall for a LAPB frame | |
159 | */ | |
160 | static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama) | |
161 | { | |
162 | int queued = 0; | |
163 | ||
164 | if (ax25->state == AX25_STATE_0) | |
165 | return 0; | |
166 | ||
167 | switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { | |
168 | case AX25_PROTO_STD_SIMPLEX: | |
169 | case AX25_PROTO_STD_DUPLEX: | |
170 | queued = ax25_std_frame_in(ax25, skb, type); | |
171 | break; | |
172 | ||
173 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
174 | case AX25_PROTO_DAMA_SLAVE: | |
175 | if (dama || ax25->ax25_dev->dama.slave) | |
176 | queued = ax25_ds_frame_in(ax25, skb, type); | |
177 | else | |
178 | queued = ax25_std_frame_in(ax25, skb, type); | |
179 | break; | |
180 | #endif | |
181 | } | |
182 | ||
183 | return queued; | |
184 | } | |
185 | ||
186 | static int ax25_rcv(struct sk_buff *skb, struct net_device *dev, | |
187 | ax25_address *dev_addr, struct packet_type *ptype) | |
188 | { | |
189 | ax25_address src, dest, *next_digi = NULL; | |
190 | int type = 0, mine = 0, dama; | |
191 | struct sock *make, *sk; | |
192 | ax25_digi dp, reverse_dp; | |
193 | ax25_cb *ax25; | |
194 | ax25_dev *ax25_dev; | |
195 | ||
196 | /* | |
197 | * Process the AX.25/LAPB frame. | |
198 | */ | |
199 | ||
200 | skb->h.raw = skb->data; | |
201 | ||
202 | if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) { | |
203 | kfree_skb(skb); | |
204 | return 0; | |
205 | } | |
206 | ||
207 | /* | |
208 | * Parse the address header. | |
209 | */ | |
210 | ||
211 | if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) { | |
212 | kfree_skb(skb); | |
213 | return 0; | |
214 | } | |
215 | ||
216 | /* | |
217 | * Ours perhaps ? | |
218 | */ | |
219 | if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */ | |
220 | next_digi = &dp.calls[dp.lastrepeat + 1]; | |
221 | ||
222 | /* | |
223 | * Pull of the AX.25 headers leaving the CTRL/PID bytes | |
224 | */ | |
225 | skb_pull(skb, ax25_addr_size(&dp)); | |
226 | ||
227 | /* For our port addresses ? */ | |
228 | if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi) | |
229 | mine = 1; | |
230 | ||
231 | /* Also match on any registered callsign from L3/4 */ | |
232 | if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi) | |
233 | mine = 1; | |
234 | ||
235 | /* UI frame - bypass LAPB processing */ | |
236 | if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) { | |
237 | skb->h.raw = skb->data + 2; /* skip control and pid */ | |
238 | ||
239 | ax25_send_to_raw(&dest, skb, skb->data[1]); | |
240 | ||
241 | if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) { | |
242 | kfree_skb(skb); | |
243 | return 0; | |
244 | } | |
245 | ||
246 | /* Now we are pointing at the pid byte */ | |
247 | switch (skb->data[1]) { | |
1da177e4 LT |
248 | case AX25_P_IP: |
249 | skb_pull(skb,2); /* drop PID/CTRL */ | |
250 | skb->h.raw = skb->data; | |
251 | skb->nh.raw = skb->data; | |
252 | skb->dev = dev; | |
253 | skb->pkt_type = PACKET_HOST; | |
254 | skb->protocol = htons(ETH_P_IP); | |
98a82feb | 255 | netif_rx(skb); |
1da177e4 LT |
256 | break; |
257 | ||
258 | case AX25_P_ARP: | |
259 | skb_pull(skb,2); | |
260 | skb->h.raw = skb->data; | |
261 | skb->nh.raw = skb->data; | |
262 | skb->dev = dev; | |
263 | skb->pkt_type = PACKET_HOST; | |
264 | skb->protocol = htons(ETH_P_ARP); | |
98a82feb | 265 | netif_rx(skb); |
1da177e4 | 266 | break; |
1da177e4 LT |
267 | case AX25_P_TEXT: |
268 | /* Now find a suitable dgram socket */ | |
269 | sk = ax25_get_socket(&dest, &src, SOCK_DGRAM); | |
270 | if (sk != NULL) { | |
271 | bh_lock_sock(sk); | |
272 | if (atomic_read(&sk->sk_rmem_alloc) >= | |
273 | sk->sk_rcvbuf) { | |
274 | kfree_skb(skb); | |
275 | } else { | |
276 | /* | |
277 | * Remove the control and PID. | |
278 | */ | |
279 | skb_pull(skb, 2); | |
280 | if (sock_queue_rcv_skb(sk, skb) != 0) | |
281 | kfree_skb(skb); | |
282 | } | |
283 | bh_unlock_sock(sk); | |
284 | sock_put(sk); | |
285 | } else { | |
286 | kfree_skb(skb); | |
287 | } | |
288 | break; | |
289 | ||
290 | default: | |
291 | kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */ | |
292 | break; | |
293 | } | |
294 | ||
295 | return 0; | |
296 | } | |
297 | ||
298 | /* | |
299 | * Is connected mode supported on this device ? | |
300 | * If not, should we DM the incoming frame (except DMs) or | |
301 | * silently ignore them. For now we stay quiet. | |
302 | */ | |
303 | if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) { | |
304 | kfree_skb(skb); | |
305 | return 0; | |
306 | } | |
307 | ||
308 | /* LAPB */ | |
309 | ||
310 | /* AX.25 state 1-4 */ | |
311 | ||
312 | ax25_digi_invert(&dp, &reverse_dp); | |
313 | ||
314 | if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) { | |
315 | /* | |
316 | * Process the frame. If it is queued up internally it | |
317 | * returns one otherwise we free it immediately. This | |
318 | * routine itself wakes the user context layers so we do | |
319 | * no further work | |
320 | */ | |
321 | if (ax25_process_rx_frame(ax25, skb, type, dama) == 0) | |
322 | kfree_skb(skb); | |
323 | ||
324 | ax25_cb_put(ax25); | |
325 | return 0; | |
326 | } | |
327 | ||
328 | /* AX.25 state 0 (disconnected) */ | |
329 | ||
330 | /* a) received not a SABM(E) */ | |
331 | ||
332 | if ((*skb->data & ~AX25_PF) != AX25_SABM && | |
333 | (*skb->data & ~AX25_PF) != AX25_SABME) { | |
334 | /* | |
335 | * Never reply to a DM. Also ignore any connects for | |
336 | * addresses that are not our interfaces and not a socket. | |
337 | */ | |
338 | if ((*skb->data & ~AX25_PF) != AX25_DM && mine) | |
339 | ax25_return_dm(dev, &src, &dest, &dp); | |
340 | ||
341 | kfree_skb(skb); | |
342 | return 0; | |
343 | } | |
344 | ||
345 | /* b) received SABM(E) */ | |
346 | ||
347 | if (dp.lastrepeat + 1 == dp.ndigi) | |
348 | sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET); | |
349 | else | |
350 | sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET); | |
351 | ||
352 | if (sk != NULL) { | |
353 | bh_lock_sock(sk); | |
354 | if (sk_acceptq_is_full(sk) || | |
355 | (make = ax25_make_new(sk, ax25_dev)) == NULL) { | |
356 | if (mine) | |
357 | ax25_return_dm(dev, &src, &dest, &dp); | |
358 | kfree_skb(skb); | |
359 | bh_unlock_sock(sk); | |
360 | sock_put(sk); | |
361 | ||
362 | return 0; | |
363 | } | |
364 | ||
365 | ax25 = ax25_sk(make); | |
366 | skb_set_owner_r(skb, make); | |
367 | skb_queue_head(&sk->sk_receive_queue, skb); | |
368 | ||
369 | make->sk_state = TCP_ESTABLISHED; | |
370 | ||
371 | sk->sk_ack_backlog++; | |
372 | bh_unlock_sock(sk); | |
373 | } else { | |
374 | if (!mine) { | |
375 | kfree_skb(skb); | |
376 | return 0; | |
377 | } | |
378 | ||
379 | if ((ax25 = ax25_create_cb()) == NULL) { | |
380 | ax25_return_dm(dev, &src, &dest, &dp); | |
381 | kfree_skb(skb); | |
382 | return 0; | |
383 | } | |
384 | ||
385 | ax25_fillin_cb(ax25, ax25_dev); | |
386 | } | |
387 | ||
388 | ax25->source_addr = dest; | |
389 | ax25->dest_addr = src; | |
390 | ||
391 | /* | |
392 | * Sort out any digipeated paths. | |
393 | */ | |
394 | if (dp.ndigi && !ax25->digipeat && | |
395 | (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) { | |
396 | kfree_skb(skb); | |
397 | ax25_destroy_socket(ax25); | |
398 | if (sk) | |
399 | sock_put(sk); | |
400 | return 0; | |
401 | } | |
402 | ||
403 | if (dp.ndigi == 0) { | |
a51482bd JJ |
404 | kfree(ax25->digipeat); |
405 | ax25->digipeat = NULL; | |
1da177e4 LT |
406 | } else { |
407 | /* Reverse the source SABM's path */ | |
408 | memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi)); | |
409 | } | |
410 | ||
411 | if ((*skb->data & ~AX25_PF) == AX25_SABME) { | |
412 | ax25->modulus = AX25_EMODULUS; | |
413 | ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW]; | |
414 | } else { | |
415 | ax25->modulus = AX25_MODULUS; | |
416 | ax25->window = ax25_dev->values[AX25_VALUES_WINDOW]; | |
417 | } | |
418 | ||
419 | ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE); | |
420 | ||
421 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
422 | if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE) | |
423 | ax25_dama_on(ax25); | |
424 | #endif | |
425 | ||
426 | ax25->state = AX25_STATE_3; | |
427 | ||
428 | ax25_cb_add(ax25); | |
429 | ||
430 | ax25_start_heartbeat(ax25); | |
431 | ax25_start_t3timer(ax25); | |
432 | ax25_start_idletimer(ax25); | |
433 | ||
434 | if (sk) { | |
435 | if (!sock_flag(sk, SOCK_DEAD)) | |
436 | sk->sk_data_ready(sk, skb->len); | |
437 | sock_put(sk); | |
438 | } else | |
439 | kfree_skb(skb); | |
440 | ||
441 | return 0; | |
442 | } | |
443 | ||
444 | /* | |
445 | * Receive an AX.25 frame via a SLIP interface. | |
446 | */ | |
447 | int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev, | |
f2ccd8fa | 448 | struct packet_type *ptype, struct net_device *orig_dev) |
1da177e4 LT |
449 | { |
450 | skb->sk = NULL; /* Initially we don't know who it's for */ | |
451 | skb->destructor = NULL; /* Who initializes this, dammit?! */ | |
452 | ||
453 | if ((*skb->data & 0x0F) != 0) { | |
454 | kfree_skb(skb); /* Not a KISS data frame */ | |
455 | return 0; | |
456 | } | |
457 | ||
458 | skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */ | |
459 | ||
460 | return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype); | |
461 | } |