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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> | |
1da177e4 LT |
17 | #include <linux/timer.h> |
18 | #include <linux/string.h> | |
19 | #include <linux/sockios.h> | |
20 | #include <linux/net.h> | |
21 | #include <net/ax25.h> | |
22 | #include <linux/inet.h> | |
23 | #include <linux/netdevice.h> | |
24 | #include <linux/skbuff.h> | |
25 | #include <linux/netfilter.h> | |
26 | #include <net/sock.h> | |
c752f073 | 27 | #include <net/tcp_states.h> |
1da177e4 LT |
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 | /* | |
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 | skbn->h.raw = skbn->data; | |
65 | skbn->nh.raw = skbn->data; | |
66 | ||
67 | /* Copy data from the fragments */ | |
68 | while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) { | |
69 | memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len); | |
70 | kfree_skb(skbo); | |
71 | } | |
72 | ||
73 | ax25->fraglen = 0; | |
74 | ||
75 | if (ax25_rx_iframe(ax25, skbn) == 0) | |
76 | kfree_skb(skbn); | |
77 | } | |
78 | ||
79 | return 1; | |
80 | } | |
81 | } | |
82 | } else { | |
83 | /* First fragment received */ | |
84 | if (*skb->data & AX25_SEG_FIRST) { | |
85 | skb_queue_purge(&ax25->frag_queue); | |
86 | ax25->fragno = *skb->data & AX25_SEG_REM; | |
87 | skb_pull(skb, 1); /* skip fragno */ | |
88 | ax25->fraglen = skb->len; | |
89 | skb_queue_tail(&ax25->frag_queue, skb); | |
90 | return 1; | |
91 | } | |
92 | } | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
97 | /* | |
98 | * This is where all valid I frames are sent to, to be dispatched to | |
99 | * whichever protocol requires them. | |
100 | */ | |
101 | int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb) | |
102 | { | |
103 | int (*func)(struct sk_buff *, ax25_cb *); | |
1da177e4 | 104 | unsigned char pid; |
bde3445c | 105 | int queued = 0; |
1da177e4 LT |
106 | |
107 | if (skb == NULL) return 0; | |
108 | ||
109 | ax25_start_idletimer(ax25); | |
110 | ||
111 | pid = *skb->data; | |
112 | ||
1da177e4 LT |
113 | if (pid == AX25_P_IP) { |
114 | /* working around a TCP bug to keep additional listeners | |
115 | * happy. TCP re-uses the buffer and destroys the original | |
116 | * content. | |
117 | */ | |
118 | struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC); | |
119 | if (skbn != NULL) { | |
120 | kfree_skb(skb); | |
121 | skb = skbn; | |
122 | } | |
123 | ||
124 | skb_pull(skb, 1); /* Remove PID */ | |
459a98ed | 125 | skb_reset_mac_header(skb); |
1da177e4 LT |
126 | skb->nh.raw = skb->data; |
127 | skb->dev = ax25->ax25_dev->dev; | |
128 | skb->pkt_type = PACKET_HOST; | |
129 | skb->protocol = htons(ETH_P_IP); | |
98a82feb | 130 | netif_rx(skb); |
1da177e4 LT |
131 | return 1; |
132 | } | |
1da177e4 LT |
133 | if (pid == AX25_P_SEGMENT) { |
134 | skb_pull(skb, 1); /* Remove PID */ | |
135 | return ax25_rx_fragment(ax25, skb); | |
136 | } | |
137 | ||
138 | if ((func = ax25_protocol_function(pid)) != NULL) { | |
139 | skb_pull(skb, 1); /* Remove PID */ | |
140 | return (*func)(skb, ax25); | |
141 | } | |
142 | ||
143 | if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) { | |
144 | if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) || | |
145 | ax25->pidincl) { | |
146 | if (sock_queue_rcv_skb(ax25->sk, skb) == 0) | |
147 | queued = 1; | |
148 | else | |
149 | ax25->condition |= AX25_COND_OWN_RX_BUSY; | |
150 | } | |
151 | } | |
152 | ||
153 | return queued; | |
154 | } | |
155 | ||
156 | /* | |
157 | * Higher level upcall for a LAPB frame | |
158 | */ | |
159 | static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama) | |
160 | { | |
161 | int queued = 0; | |
162 | ||
163 | if (ax25->state == AX25_STATE_0) | |
164 | return 0; | |
165 | ||
166 | switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { | |
167 | case AX25_PROTO_STD_SIMPLEX: | |
168 | case AX25_PROTO_STD_DUPLEX: | |
169 | queued = ax25_std_frame_in(ax25, skb, type); | |
170 | break; | |
171 | ||
172 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
173 | case AX25_PROTO_DAMA_SLAVE: | |
174 | if (dama || ax25->ax25_dev->dama.slave) | |
175 | queued = ax25_ds_frame_in(ax25, skb, type); | |
176 | else | |
177 | queued = ax25_std_frame_in(ax25, skb, type); | |
178 | break; | |
179 | #endif | |
180 | } | |
181 | ||
182 | return queued; | |
183 | } | |
184 | ||
185 | static int ax25_rcv(struct sk_buff *skb, struct net_device *dev, | |
186 | ax25_address *dev_addr, struct packet_type *ptype) | |
187 | { | |
188 | ax25_address src, dest, *next_digi = NULL; | |
189 | int type = 0, mine = 0, dama; | |
190 | struct sock *make, *sk; | |
191 | ax25_digi dp, reverse_dp; | |
192 | ax25_cb *ax25; | |
193 | ax25_dev *ax25_dev; | |
194 | ||
195 | /* | |
196 | * Process the AX.25/LAPB frame. | |
197 | */ | |
198 | ||
199 | skb->h.raw = skb->data; | |
200 | ||
201 | if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) { | |
202 | kfree_skb(skb); | |
203 | return 0; | |
204 | } | |
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 | kfree_skb(skb); | |
212 | return 0; | |
213 | } | |
214 | ||
215 | /* | |
216 | * Ours perhaps ? | |
217 | */ | |
218 | if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */ | |
219 | next_digi = &dp.calls[dp.lastrepeat + 1]; | |
220 | ||
221 | /* | |
222 | * Pull of the AX.25 headers leaving the CTRL/PID bytes | |
223 | */ | |
224 | skb_pull(skb, ax25_addr_size(&dp)); | |
225 | ||
226 | /* For our port addresses ? */ | |
227 | if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi) | |
228 | mine = 1; | |
229 | ||
230 | /* Also match on any registered callsign from L3/4 */ | |
231 | if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi) | |
232 | mine = 1; | |
233 | ||
234 | /* UI frame - bypass LAPB processing */ | |
235 | if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) { | |
236 | skb->h.raw = skb->data + 2; /* skip control and pid */ | |
237 | ||
238 | ax25_send_to_raw(&dest, skb, skb->data[1]); | |
239 | ||
240 | if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) { | |
241 | kfree_skb(skb); | |
242 | return 0; | |
243 | } | |
244 | ||
245 | /* Now we are pointing at the pid byte */ | |
246 | switch (skb->data[1]) { | |
1da177e4 LT |
247 | case AX25_P_IP: |
248 | skb_pull(skb,2); /* drop PID/CTRL */ | |
249 | skb->h.raw = skb->data; | |
250 | skb->nh.raw = skb->data; | |
251 | skb->dev = dev; | |
252 | skb->pkt_type = PACKET_HOST; | |
253 | skb->protocol = htons(ETH_P_IP); | |
98a82feb | 254 | netif_rx(skb); |
1da177e4 LT |
255 | break; |
256 | ||
257 | case AX25_P_ARP: | |
258 | skb_pull(skb,2); | |
259 | skb->h.raw = skb->data; | |
260 | skb->nh.raw = skb->data; | |
261 | skb->dev = dev; | |
262 | skb->pkt_type = PACKET_HOST; | |
263 | skb->protocol = htons(ETH_P_ARP); | |
98a82feb | 264 | netif_rx(skb); |
1da177e4 | 265 | break; |
1da177e4 LT |
266 | case AX25_P_TEXT: |
267 | /* Now find a suitable dgram socket */ | |
268 | sk = ax25_get_socket(&dest, &src, SOCK_DGRAM); | |
269 | if (sk != NULL) { | |
270 | bh_lock_sock(sk); | |
271 | if (atomic_read(&sk->sk_rmem_alloc) >= | |
272 | sk->sk_rcvbuf) { | |
273 | kfree_skb(skb); | |
274 | } else { | |
275 | /* | |
276 | * Remove the control and PID. | |
277 | */ | |
278 | skb_pull(skb, 2); | |
279 | if (sock_queue_rcv_skb(sk, skb) != 0) | |
280 | kfree_skb(skb); | |
281 | } | |
282 | bh_unlock_sock(sk); | |
283 | sock_put(sk); | |
284 | } else { | |
285 | kfree_skb(skb); | |
286 | } | |
287 | break; | |
288 | ||
289 | default: | |
290 | kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */ | |
291 | break; | |
292 | } | |
293 | ||
294 | return 0; | |
295 | } | |
296 | ||
297 | /* | |
298 | * Is connected mode supported on this device ? | |
299 | * If not, should we DM the incoming frame (except DMs) or | |
300 | * silently ignore them. For now we stay quiet. | |
301 | */ | |
302 | if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) { | |
303 | kfree_skb(skb); | |
304 | return 0; | |
305 | } | |
306 | ||
307 | /* LAPB */ | |
308 | ||
309 | /* AX.25 state 1-4 */ | |
310 | ||
311 | ax25_digi_invert(&dp, &reverse_dp); | |
312 | ||
313 | if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) { | |
314 | /* | |
315 | * Process the frame. If it is queued up internally it | |
316 | * returns one otherwise we free it immediately. This | |
317 | * routine itself wakes the user context layers so we do | |
318 | * no further work | |
319 | */ | |
320 | if (ax25_process_rx_frame(ax25, skb, type, dama) == 0) | |
321 | kfree_skb(skb); | |
322 | ||
323 | ax25_cb_put(ax25); | |
324 | return 0; | |
325 | } | |
326 | ||
327 | /* AX.25 state 0 (disconnected) */ | |
328 | ||
329 | /* a) received not a SABM(E) */ | |
330 | ||
331 | if ((*skb->data & ~AX25_PF) != AX25_SABM && | |
332 | (*skb->data & ~AX25_PF) != AX25_SABME) { | |
333 | /* | |
334 | * Never reply to a DM. Also ignore any connects for | |
335 | * addresses that are not our interfaces and not a socket. | |
336 | */ | |
337 | if ((*skb->data & ~AX25_PF) != AX25_DM && mine) | |
338 | ax25_return_dm(dev, &src, &dest, &dp); | |
339 | ||
340 | kfree_skb(skb); | |
341 | return 0; | |
342 | } | |
343 | ||
344 | /* b) received SABM(E) */ | |
345 | ||
346 | if (dp.lastrepeat + 1 == dp.ndigi) | |
347 | sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET); | |
348 | else | |
349 | sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET); | |
350 | ||
351 | if (sk != NULL) { | |
352 | bh_lock_sock(sk); | |
353 | if (sk_acceptq_is_full(sk) || | |
354 | (make = ax25_make_new(sk, ax25_dev)) == NULL) { | |
355 | if (mine) | |
356 | ax25_return_dm(dev, &src, &dest, &dp); | |
357 | kfree_skb(skb); | |
358 | bh_unlock_sock(sk); | |
359 | sock_put(sk); | |
360 | ||
361 | return 0; | |
362 | } | |
363 | ||
364 | ax25 = ax25_sk(make); | |
365 | skb_set_owner_r(skb, make); | |
366 | skb_queue_head(&sk->sk_receive_queue, skb); | |
367 | ||
368 | make->sk_state = TCP_ESTABLISHED; | |
369 | ||
370 | sk->sk_ack_backlog++; | |
371 | bh_unlock_sock(sk); | |
372 | } else { | |
373 | if (!mine) { | |
374 | kfree_skb(skb); | |
375 | return 0; | |
376 | } | |
377 | ||
378 | if ((ax25 = ax25_create_cb()) == NULL) { | |
379 | ax25_return_dm(dev, &src, &dest, &dp); | |
380 | kfree_skb(skb); | |
381 | return 0; | |
382 | } | |
383 | ||
384 | ax25_fillin_cb(ax25, ax25_dev); | |
385 | } | |
386 | ||
387 | ax25->source_addr = dest; | |
388 | ax25->dest_addr = src; | |
389 | ||
390 | /* | |
391 | * Sort out any digipeated paths. | |
392 | */ | |
393 | if (dp.ndigi && !ax25->digipeat && | |
394 | (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) { | |
395 | kfree_skb(skb); | |
396 | ax25_destroy_socket(ax25); | |
397 | if (sk) | |
398 | sock_put(sk); | |
399 | return 0; | |
400 | } | |
401 | ||
402 | if (dp.ndigi == 0) { | |
a51482bd JJ |
403 | kfree(ax25->digipeat); |
404 | ax25->digipeat = NULL; | |
1da177e4 LT |
405 | } else { |
406 | /* Reverse the source SABM's path */ | |
407 | memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi)); | |
408 | } | |
409 | ||
410 | if ((*skb->data & ~AX25_PF) == AX25_SABME) { | |
411 | ax25->modulus = AX25_EMODULUS; | |
412 | ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW]; | |
413 | } else { | |
414 | ax25->modulus = AX25_MODULUS; | |
415 | ax25->window = ax25_dev->values[AX25_VALUES_WINDOW]; | |
416 | } | |
417 | ||
418 | ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE); | |
419 | ||
420 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
421 | if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE) | |
422 | ax25_dama_on(ax25); | |
423 | #endif | |
424 | ||
425 | ax25->state = AX25_STATE_3; | |
426 | ||
427 | ax25_cb_add(ax25); | |
428 | ||
429 | ax25_start_heartbeat(ax25); | |
430 | ax25_start_t3timer(ax25); | |
431 | ax25_start_idletimer(ax25); | |
432 | ||
433 | if (sk) { | |
434 | if (!sock_flag(sk, SOCK_DEAD)) | |
435 | sk->sk_data_ready(sk, skb->len); | |
436 | sock_put(sk); | |
437 | } else | |
438 | kfree_skb(skb); | |
439 | ||
440 | return 0; | |
441 | } | |
442 | ||
443 | /* | |
444 | * Receive an AX.25 frame via a SLIP interface. | |
445 | */ | |
446 | int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev, | |
f2ccd8fa | 447 | struct packet_type *ptype, struct net_device *orig_dev) |
1da177e4 LT |
448 | { |
449 | skb->sk = NULL; /* Initially we don't know who it's for */ | |
450 | skb->destructor = NULL; /* Who initializes this, dammit?! */ | |
451 | ||
452 | if ((*skb->data & 0x0F) != 0) { | |
453 | kfree_skb(skb); /* Not a KISS data frame */ | |
454 | return 0; | |
455 | } | |
456 | ||
457 | skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */ | |
458 | ||
459 | return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype); | |
460 | } |