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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> | |
5a0e3ad6 | 21 | #include <linux/slab.h> |
1da177e4 LT |
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; | |
c1d2bbe1 | 65 | skb_reset_network_header(skbn); |
badff6d0 | 66 | skb_reset_transport_header(skbn); |
1da177e4 LT |
67 | |
68 | /* Copy data from the fragments */ | |
69 | while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) { | |
1a4e2d09 ACM |
70 | skb_copy_from_linear_data(skbo, |
71 | skb_put(skbn, skbo->len), | |
72 | skbo->len); | |
1da177e4 LT |
73 | kfree_skb(skbo); |
74 | } | |
75 | ||
76 | ax25->fraglen = 0; | |
77 | ||
78 | if (ax25_rx_iframe(ax25, skbn) == 0) | |
79 | kfree_skb(skbn); | |
80 | } | |
81 | ||
82 | return 1; | |
83 | } | |
84 | } | |
85 | } else { | |
86 | /* First fragment received */ | |
87 | if (*skb->data & AX25_SEG_FIRST) { | |
88 | skb_queue_purge(&ax25->frag_queue); | |
89 | ax25->fragno = *skb->data & AX25_SEG_REM; | |
90 | skb_pull(skb, 1); /* skip fragno */ | |
91 | ax25->fraglen = skb->len; | |
92 | skb_queue_tail(&ax25->frag_queue, skb); | |
93 | return 1; | |
94 | } | |
95 | } | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | /* | |
101 | * This is where all valid I frames are sent to, to be dispatched to | |
102 | * whichever protocol requires them. | |
103 | */ | |
104 | int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb) | |
105 | { | |
106 | int (*func)(struct sk_buff *, ax25_cb *); | |
1da177e4 | 107 | unsigned char pid; |
bde3445c | 108 | int queued = 0; |
1da177e4 LT |
109 | |
110 | if (skb == NULL) return 0; | |
111 | ||
112 | ax25_start_idletimer(ax25); | |
113 | ||
114 | pid = *skb->data; | |
115 | ||
1da177e4 LT |
116 | if (pid == AX25_P_IP) { |
117 | /* working around a TCP bug to keep additional listeners | |
118 | * happy. TCP re-uses the buffer and destroys the original | |
119 | * content. | |
120 | */ | |
121 | struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC); | |
122 | if (skbn != NULL) { | |
123 | kfree_skb(skb); | |
124 | skb = skbn; | |
125 | } | |
126 | ||
127 | skb_pull(skb, 1); /* Remove PID */ | |
c6e6ca71 | 128 | skb->mac_header = skb->network_header; |
c1d2bbe1 | 129 | skb_reset_network_header(skb); |
1da177e4 LT |
130 | skb->dev = ax25->ax25_dev->dev; |
131 | skb->pkt_type = PACKET_HOST; | |
132 | skb->protocol = htons(ETH_P_IP); | |
98a82feb | 133 | netif_rx(skb); |
1da177e4 LT |
134 | return 1; |
135 | } | |
1da177e4 LT |
136 | if (pid == AX25_P_SEGMENT) { |
137 | skb_pull(skb, 1); /* Remove PID */ | |
138 | return ax25_rx_fragment(ax25, skb); | |
139 | } | |
140 | ||
141 | if ((func = ax25_protocol_function(pid)) != NULL) { | |
142 | skb_pull(skb, 1); /* Remove PID */ | |
143 | return (*func)(skb, ax25); | |
144 | } | |
145 | ||
146 | if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) { | |
147 | if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) || | |
148 | ax25->pidincl) { | |
149 | if (sock_queue_rcv_skb(ax25->sk, skb) == 0) | |
150 | queued = 1; | |
151 | else | |
152 | ax25->condition |= AX25_COND_OWN_RX_BUSY; | |
153 | } | |
154 | } | |
155 | ||
156 | return queued; | |
157 | } | |
158 | ||
159 | /* | |
160 | * Higher level upcall for a LAPB frame | |
161 | */ | |
162 | static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama) | |
163 | { | |
164 | int queued = 0; | |
165 | ||
166 | if (ax25->state == AX25_STATE_0) | |
167 | return 0; | |
168 | ||
169 | switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { | |
170 | case AX25_PROTO_STD_SIMPLEX: | |
171 | case AX25_PROTO_STD_DUPLEX: | |
172 | queued = ax25_std_frame_in(ax25, skb, type); | |
173 | break; | |
174 | ||
175 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
176 | case AX25_PROTO_DAMA_SLAVE: | |
177 | if (dama || ax25->ax25_dev->dama.slave) | |
178 | queued = ax25_ds_frame_in(ax25, skb, type); | |
179 | else | |
180 | queued = ax25_std_frame_in(ax25, skb, type); | |
181 | break; | |
182 | #endif | |
183 | } | |
184 | ||
185 | return queued; | |
186 | } | |
187 | ||
188 | static int ax25_rcv(struct sk_buff *skb, struct net_device *dev, | |
189 | ax25_address *dev_addr, struct packet_type *ptype) | |
190 | { | |
191 | ax25_address src, dest, *next_digi = NULL; | |
192 | int type = 0, mine = 0, dama; | |
193 | struct sock *make, *sk; | |
194 | ax25_digi dp, reverse_dp; | |
195 | ax25_cb *ax25; | |
196 | ax25_dev *ax25_dev; | |
197 | ||
198 | /* | |
199 | * Process the AX.25/LAPB frame. | |
200 | */ | |
201 | ||
badff6d0 | 202 | skb_reset_transport_header(skb); |
1da177e4 | 203 | |
0eae1b98 IJ |
204 | if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) |
205 | goto free; | |
1da177e4 LT |
206 | |
207 | /* | |
208 | * Parse the address header. | |
209 | */ | |
210 | ||
0eae1b98 IJ |
211 | if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) |
212 | goto free; | |
1da177e4 LT |
213 | |
214 | /* | |
215 | * Ours perhaps ? | |
216 | */ | |
217 | if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */ | |
218 | next_digi = &dp.calls[dp.lastrepeat + 1]; | |
219 | ||
220 | /* | |
221 | * Pull of the AX.25 headers leaving the CTRL/PID bytes | |
222 | */ | |
223 | skb_pull(skb, ax25_addr_size(&dp)); | |
224 | ||
225 | /* For our port addresses ? */ | |
226 | if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi) | |
227 | mine = 1; | |
228 | ||
229 | /* Also match on any registered callsign from L3/4 */ | |
230 | if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi) | |
231 | mine = 1; | |
232 | ||
233 | /* UI frame - bypass LAPB processing */ | |
234 | if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) { | |
967b05f6 | 235 | skb_set_transport_header(skb, 2); /* skip control and pid */ |
1da177e4 LT |
236 | |
237 | ax25_send_to_raw(&dest, skb, skb->data[1]); | |
238 | ||
0eae1b98 IJ |
239 | if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) |
240 | goto free; | |
1da177e4 LT |
241 | |
242 | /* Now we are pointing at the pid byte */ | |
243 | switch (skb->data[1]) { | |
1da177e4 LT |
244 | case AX25_P_IP: |
245 | skb_pull(skb,2); /* drop PID/CTRL */ | |
badff6d0 | 246 | skb_reset_transport_header(skb); |
c1d2bbe1 | 247 | skb_reset_network_header(skb); |
1da177e4 LT |
248 | skb->dev = dev; |
249 | skb->pkt_type = PACKET_HOST; | |
250 | skb->protocol = htons(ETH_P_IP); | |
98a82feb | 251 | netif_rx(skb); |
1da177e4 LT |
252 | break; |
253 | ||
254 | case AX25_P_ARP: | |
255 | skb_pull(skb,2); | |
badff6d0 | 256 | skb_reset_transport_header(skb); |
c1d2bbe1 | 257 | skb_reset_network_header(skb); |
1da177e4 LT |
258 | skb->dev = dev; |
259 | skb->pkt_type = PACKET_HOST; | |
260 | skb->protocol = htons(ETH_P_ARP); | |
98a82feb | 261 | netif_rx(skb); |
1da177e4 | 262 | break; |
1da177e4 LT |
263 | case AX25_P_TEXT: |
264 | /* Now find a suitable dgram socket */ | |
265 | sk = ax25_get_socket(&dest, &src, SOCK_DGRAM); | |
266 | if (sk != NULL) { | |
267 | bh_lock_sock(sk); | |
268 | if (atomic_read(&sk->sk_rmem_alloc) >= | |
269 | sk->sk_rcvbuf) { | |
270 | kfree_skb(skb); | |
271 | } else { | |
272 | /* | |
273 | * Remove the control and PID. | |
274 | */ | |
275 | skb_pull(skb, 2); | |
276 | if (sock_queue_rcv_skb(sk, skb) != 0) | |
277 | kfree_skb(skb); | |
278 | } | |
279 | bh_unlock_sock(sk); | |
280 | sock_put(sk); | |
281 | } else { | |
282 | kfree_skb(skb); | |
283 | } | |
284 | break; | |
285 | ||
286 | default: | |
287 | kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */ | |
288 | break; | |
289 | } | |
290 | ||
291 | return 0; | |
292 | } | |
293 | ||
294 | /* | |
295 | * Is connected mode supported on this device ? | |
296 | * If not, should we DM the incoming frame (except DMs) or | |
297 | * silently ignore them. For now we stay quiet. | |
298 | */ | |
0eae1b98 IJ |
299 | if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) |
300 | goto free; | |
1da177e4 LT |
301 | |
302 | /* LAPB */ | |
303 | ||
304 | /* AX.25 state 1-4 */ | |
305 | ||
306 | ax25_digi_invert(&dp, &reverse_dp); | |
307 | ||
308 | if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) { | |
309 | /* | |
310 | * Process the frame. If it is queued up internally it | |
311 | * returns one otherwise we free it immediately. This | |
312 | * routine itself wakes the user context layers so we do | |
313 | * no further work | |
314 | */ | |
315 | if (ax25_process_rx_frame(ax25, skb, type, dama) == 0) | |
316 | kfree_skb(skb); | |
317 | ||
318 | ax25_cb_put(ax25); | |
319 | return 0; | |
320 | } | |
321 | ||
322 | /* AX.25 state 0 (disconnected) */ | |
323 | ||
324 | /* a) received not a SABM(E) */ | |
325 | ||
326 | if ((*skb->data & ~AX25_PF) != AX25_SABM && | |
327 | (*skb->data & ~AX25_PF) != AX25_SABME) { | |
328 | /* | |
329 | * Never reply to a DM. Also ignore any connects for | |
330 | * addresses that are not our interfaces and not a socket. | |
331 | */ | |
332 | if ((*skb->data & ~AX25_PF) != AX25_DM && mine) | |
333 | ax25_return_dm(dev, &src, &dest, &dp); | |
334 | ||
0eae1b98 | 335 | goto free; |
1da177e4 LT |
336 | } |
337 | ||
338 | /* b) received SABM(E) */ | |
339 | ||
340 | if (dp.lastrepeat + 1 == dp.ndigi) | |
341 | sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET); | |
342 | else | |
343 | sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET); | |
344 | ||
345 | if (sk != NULL) { | |
346 | bh_lock_sock(sk); | |
347 | if (sk_acceptq_is_full(sk) || | |
348 | (make = ax25_make_new(sk, ax25_dev)) == NULL) { | |
349 | if (mine) | |
350 | ax25_return_dm(dev, &src, &dest, &dp); | |
351 | kfree_skb(skb); | |
352 | bh_unlock_sock(sk); | |
353 | sock_put(sk); | |
354 | ||
355 | return 0; | |
356 | } | |
357 | ||
358 | ax25 = ax25_sk(make); | |
359 | skb_set_owner_r(skb, make); | |
360 | skb_queue_head(&sk->sk_receive_queue, skb); | |
361 | ||
362 | make->sk_state = TCP_ESTABLISHED; | |
363 | ||
364 | sk->sk_ack_backlog++; | |
365 | bh_unlock_sock(sk); | |
366 | } else { | |
0eae1b98 IJ |
367 | if (!mine) |
368 | goto free; | |
1da177e4 LT |
369 | |
370 | if ((ax25 = ax25_create_cb()) == NULL) { | |
371 | ax25_return_dm(dev, &src, &dest, &dp); | |
0eae1b98 | 372 | goto free; |
1da177e4 LT |
373 | } |
374 | ||
375 | ax25_fillin_cb(ax25, ax25_dev); | |
376 | } | |
377 | ||
378 | ax25->source_addr = dest; | |
379 | ax25->dest_addr = src; | |
380 | ||
381 | /* | |
382 | * Sort out any digipeated paths. | |
383 | */ | |
384 | if (dp.ndigi && !ax25->digipeat && | |
385 | (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) { | |
386 | kfree_skb(skb); | |
387 | ax25_destroy_socket(ax25); | |
388 | if (sk) | |
389 | sock_put(sk); | |
390 | return 0; | |
391 | } | |
392 | ||
393 | if (dp.ndigi == 0) { | |
a51482bd JJ |
394 | kfree(ax25->digipeat); |
395 | ax25->digipeat = NULL; | |
1da177e4 LT |
396 | } else { |
397 | /* Reverse the source SABM's path */ | |
398 | memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi)); | |
399 | } | |
400 | ||
401 | if ((*skb->data & ~AX25_PF) == AX25_SABME) { | |
402 | ax25->modulus = AX25_EMODULUS; | |
403 | ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW]; | |
404 | } else { | |
405 | ax25->modulus = AX25_MODULUS; | |
406 | ax25->window = ax25_dev->values[AX25_VALUES_WINDOW]; | |
407 | } | |
408 | ||
409 | ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE); | |
410 | ||
411 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
412 | if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE) | |
413 | ax25_dama_on(ax25); | |
414 | #endif | |
415 | ||
416 | ax25->state = AX25_STATE_3; | |
417 | ||
418 | ax25_cb_add(ax25); | |
419 | ||
420 | ax25_start_heartbeat(ax25); | |
421 | ax25_start_t3timer(ax25); | |
422 | ax25_start_idletimer(ax25); | |
423 | ||
424 | if (sk) { | |
425 | if (!sock_flag(sk, SOCK_DEAD)) | |
426 | sk->sk_data_ready(sk, skb->len); | |
427 | sock_put(sk); | |
0eae1b98 IJ |
428 | } else { |
429 | free: | |
1da177e4 | 430 | kfree_skb(skb); |
0eae1b98 | 431 | } |
1da177e4 LT |
432 | return 0; |
433 | } | |
434 | ||
435 | /* | |
436 | * Receive an AX.25 frame via a SLIP interface. | |
437 | */ | |
438 | int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev, | |
f2ccd8fa | 439 | struct packet_type *ptype, struct net_device *orig_dev) |
1da177e4 | 440 | { |
d55d87fd | 441 | skb_orphan(skb); |
1da177e4 | 442 | |
721499e8 | 443 | if (!net_eq(dev_net(dev), &init_net)) { |
e730c155 EB |
444 | kfree_skb(skb); |
445 | return 0; | |
446 | } | |
447 | ||
1da177e4 LT |
448 | if ((*skb->data & 0x0F) != 0) { |
449 | kfree_skb(skb); /* Not a KISS data frame */ | |
450 | return 0; | |
451 | } | |
452 | ||
453 | skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */ | |
454 | ||
455 | return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype); | |
456 | } |