Commit | Line | Data |
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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> | |
1da177e4 | 26 | #include <net/sock.h> |
c752f073 | 27 | #include <net/tcp_states.h> |
1da177e4 | 28 | #include <asm/uaccess.h> |
1da177e4 LT |
29 | #include <linux/fcntl.h> |
30 | #include <linux/mm.h> | |
31 | #include <linux/interrupt.h> | |
32 | ||
33 | /* | |
34 | * Given a fragment, queue it on the fragment queue and if the fragment | |
35 | * is complete, send it back to ax25_rx_iframe. | |
36 | */ | |
37 | static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb) | |
38 | { | |
39 | struct sk_buff *skbn, *skbo; | |
40 | ||
41 | if (ax25->fragno != 0) { | |
42 | if (!(*skb->data & AX25_SEG_FIRST)) { | |
43 | if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) { | |
44 | /* Enqueue fragment */ | |
45 | ax25->fragno = *skb->data & AX25_SEG_REM; | |
46 | skb_pull(skb, 1); /* skip fragno */ | |
47 | ax25->fraglen += skb->len; | |
48 | skb_queue_tail(&ax25->frag_queue, skb); | |
49 | ||
50 | /* Last fragment received ? */ | |
51 | if (ax25->fragno == 0) { | |
52 | skbn = alloc_skb(AX25_MAX_HEADER_LEN + | |
53 | ax25->fraglen, | |
54 | GFP_ATOMIC); | |
55 | if (!skbn) { | |
56 | skb_queue_purge(&ax25->frag_queue); | |
57 | return 1; | |
58 | } | |
59 | ||
60 | skb_reserve(skbn, AX25_MAX_HEADER_LEN); | |
61 | ||
62 | skbn->dev = ax25->ax25_dev->dev; | |
c1d2bbe1 | 63 | skb_reset_network_header(skbn); |
badff6d0 | 64 | skb_reset_transport_header(skbn); |
1da177e4 LT |
65 | |
66 | /* Copy data from the fragments */ | |
67 | while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) { | |
1a4e2d09 ACM |
68 | skb_copy_from_linear_data(skbo, |
69 | skb_put(skbn, skbo->len), | |
70 | skbo->len); | |
1da177e4 LT |
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 */ | |
c6e6ca71 | 126 | skb->mac_header = skb->network_header; |
c1d2bbe1 | 127 | skb_reset_network_header(skb); |
1da177e4 LT |
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 | ||
badff6d0 | 200 | skb_reset_transport_header(skb); |
1da177e4 | 201 | |
0eae1b98 IJ |
202 | if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) |
203 | goto free; | |
1da177e4 LT |
204 | |
205 | /* | |
206 | * Parse the address header. | |
207 | */ | |
208 | ||
0eae1b98 IJ |
209 | if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) |
210 | goto free; | |
1da177e4 LT |
211 | |
212 | /* | |
213 | * Ours perhaps ? | |
214 | */ | |
215 | if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */ | |
216 | next_digi = &dp.calls[dp.lastrepeat + 1]; | |
217 | ||
218 | /* | |
219 | * Pull of the AX.25 headers leaving the CTRL/PID bytes | |
220 | */ | |
221 | skb_pull(skb, ax25_addr_size(&dp)); | |
222 | ||
223 | /* For our port addresses ? */ | |
224 | if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi) | |
225 | mine = 1; | |
226 | ||
227 | /* Also match on any registered callsign from L3/4 */ | |
228 | if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi) | |
229 | mine = 1; | |
230 | ||
231 | /* UI frame - bypass LAPB processing */ | |
232 | if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) { | |
967b05f6 | 233 | skb_set_transport_header(skb, 2); /* skip control and pid */ |
1da177e4 LT |
234 | |
235 | ax25_send_to_raw(&dest, skb, skb->data[1]); | |
236 | ||
0eae1b98 IJ |
237 | if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) |
238 | goto free; | |
1da177e4 LT |
239 | |
240 | /* Now we are pointing at the pid byte */ | |
241 | switch (skb->data[1]) { | |
1da177e4 LT |
242 | case AX25_P_IP: |
243 | skb_pull(skb,2); /* drop PID/CTRL */ | |
badff6d0 | 244 | skb_reset_transport_header(skb); |
c1d2bbe1 | 245 | skb_reset_network_header(skb); |
1da177e4 LT |
246 | skb->dev = dev; |
247 | skb->pkt_type = PACKET_HOST; | |
248 | skb->protocol = htons(ETH_P_IP); | |
98a82feb | 249 | netif_rx(skb); |
1da177e4 LT |
250 | break; |
251 | ||
252 | case AX25_P_ARP: | |
253 | skb_pull(skb,2); | |
badff6d0 | 254 | skb_reset_transport_header(skb); |
c1d2bbe1 | 255 | skb_reset_network_header(skb); |
1da177e4 LT |
256 | skb->dev = dev; |
257 | skb->pkt_type = PACKET_HOST; | |
258 | skb->protocol = htons(ETH_P_ARP); | |
98a82feb | 259 | netif_rx(skb); |
1da177e4 | 260 | break; |
1da177e4 LT |
261 | case AX25_P_TEXT: |
262 | /* Now find a suitable dgram socket */ | |
263 | sk = ax25_get_socket(&dest, &src, SOCK_DGRAM); | |
264 | if (sk != NULL) { | |
265 | bh_lock_sock(sk); | |
266 | if (atomic_read(&sk->sk_rmem_alloc) >= | |
267 | sk->sk_rcvbuf) { | |
268 | kfree_skb(skb); | |
269 | } else { | |
270 | /* | |
271 | * Remove the control and PID. | |
272 | */ | |
273 | skb_pull(skb, 2); | |
274 | if (sock_queue_rcv_skb(sk, skb) != 0) | |
275 | kfree_skb(skb); | |
276 | } | |
277 | bh_unlock_sock(sk); | |
278 | sock_put(sk); | |
279 | } else { | |
280 | kfree_skb(skb); | |
281 | } | |
282 | break; | |
283 | ||
284 | default: | |
285 | kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */ | |
286 | break; | |
287 | } | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
292 | /* | |
293 | * Is connected mode supported on this device ? | |
294 | * If not, should we DM the incoming frame (except DMs) or | |
295 | * silently ignore them. For now we stay quiet. | |
296 | */ | |
0eae1b98 IJ |
297 | if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) |
298 | goto free; | |
1da177e4 LT |
299 | |
300 | /* LAPB */ | |
301 | ||
302 | /* AX.25 state 1-4 */ | |
303 | ||
304 | ax25_digi_invert(&dp, &reverse_dp); | |
305 | ||
306 | if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) { | |
307 | /* | |
308 | * Process the frame. If it is queued up internally it | |
309 | * returns one otherwise we free it immediately. This | |
310 | * routine itself wakes the user context layers so we do | |
311 | * no further work | |
312 | */ | |
313 | if (ax25_process_rx_frame(ax25, skb, type, dama) == 0) | |
314 | kfree_skb(skb); | |
315 | ||
316 | ax25_cb_put(ax25); | |
317 | return 0; | |
318 | } | |
319 | ||
320 | /* AX.25 state 0 (disconnected) */ | |
321 | ||
322 | /* a) received not a SABM(E) */ | |
323 | ||
324 | if ((*skb->data & ~AX25_PF) != AX25_SABM && | |
325 | (*skb->data & ~AX25_PF) != AX25_SABME) { | |
326 | /* | |
327 | * Never reply to a DM. Also ignore any connects for | |
328 | * addresses that are not our interfaces and not a socket. | |
329 | */ | |
330 | if ((*skb->data & ~AX25_PF) != AX25_DM && mine) | |
331 | ax25_return_dm(dev, &src, &dest, &dp); | |
332 | ||
0eae1b98 | 333 | goto free; |
1da177e4 LT |
334 | } |
335 | ||
336 | /* b) received SABM(E) */ | |
337 | ||
338 | if (dp.lastrepeat + 1 == dp.ndigi) | |
339 | sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET); | |
340 | else | |
341 | sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET); | |
342 | ||
343 | if (sk != NULL) { | |
344 | bh_lock_sock(sk); | |
345 | if (sk_acceptq_is_full(sk) || | |
346 | (make = ax25_make_new(sk, ax25_dev)) == NULL) { | |
347 | if (mine) | |
348 | ax25_return_dm(dev, &src, &dest, &dp); | |
349 | kfree_skb(skb); | |
350 | bh_unlock_sock(sk); | |
351 | sock_put(sk); | |
352 | ||
353 | return 0; | |
354 | } | |
355 | ||
3200392b | 356 | ax25 = sk_to_ax25(make); |
1da177e4 LT |
357 | skb_set_owner_r(skb, make); |
358 | skb_queue_head(&sk->sk_receive_queue, skb); | |
359 | ||
360 | make->sk_state = TCP_ESTABLISHED; | |
361 | ||
362 | sk->sk_ack_backlog++; | |
363 | bh_unlock_sock(sk); | |
364 | } else { | |
0eae1b98 IJ |
365 | if (!mine) |
366 | goto free; | |
1da177e4 LT |
367 | |
368 | if ((ax25 = ax25_create_cb()) == NULL) { | |
369 | ax25_return_dm(dev, &src, &dest, &dp); | |
0eae1b98 | 370 | goto free; |
1da177e4 LT |
371 | } |
372 | ||
373 | ax25_fillin_cb(ax25, ax25_dev); | |
374 | } | |
375 | ||
376 | ax25->source_addr = dest; | |
377 | ax25->dest_addr = src; | |
378 | ||
379 | /* | |
380 | * Sort out any digipeated paths. | |
381 | */ | |
382 | if (dp.ndigi && !ax25->digipeat && | |
383 | (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) { | |
384 | kfree_skb(skb); | |
385 | ax25_destroy_socket(ax25); | |
386 | if (sk) | |
387 | sock_put(sk); | |
388 | return 0; | |
389 | } | |
390 | ||
391 | if (dp.ndigi == 0) { | |
a51482bd JJ |
392 | kfree(ax25->digipeat); |
393 | ax25->digipeat = NULL; | |
1da177e4 LT |
394 | } else { |
395 | /* Reverse the source SABM's path */ | |
396 | memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi)); | |
397 | } | |
398 | ||
399 | if ((*skb->data & ~AX25_PF) == AX25_SABME) { | |
400 | ax25->modulus = AX25_EMODULUS; | |
401 | ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW]; | |
402 | } else { | |
403 | ax25->modulus = AX25_MODULUS; | |
404 | ax25->window = ax25_dev->values[AX25_VALUES_WINDOW]; | |
405 | } | |
406 | ||
407 | ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE); | |
408 | ||
409 | #ifdef CONFIG_AX25_DAMA_SLAVE | |
410 | if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE) | |
411 | ax25_dama_on(ax25); | |
412 | #endif | |
413 | ||
414 | ax25->state = AX25_STATE_3; | |
415 | ||
416 | ax25_cb_add(ax25); | |
417 | ||
418 | ax25_start_heartbeat(ax25); | |
419 | ax25_start_t3timer(ax25); | |
420 | ax25_start_idletimer(ax25); | |
421 | ||
422 | if (sk) { | |
423 | if (!sock_flag(sk, SOCK_DEAD)) | |
676d2369 | 424 | sk->sk_data_ready(sk); |
1da177e4 | 425 | sock_put(sk); |
0eae1b98 IJ |
426 | } else { |
427 | free: | |
1da177e4 | 428 | kfree_skb(skb); |
0eae1b98 | 429 | } |
1da177e4 LT |
430 | return 0; |
431 | } | |
432 | ||
433 | /* | |
434 | * Receive an AX.25 frame via a SLIP interface. | |
435 | */ | |
436 | int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev, | |
f2ccd8fa | 437 | struct packet_type *ptype, struct net_device *orig_dev) |
1da177e4 | 438 | { |
d55d87fd | 439 | skb_orphan(skb); |
1da177e4 | 440 | |
721499e8 | 441 | if (!net_eq(dev_net(dev), &init_net)) { |
e730c155 EB |
442 | kfree_skb(skb); |
443 | return 0; | |
444 | } | |
445 | ||
1da177e4 LT |
446 | if ((*skb->data & 0x0F) != 0) { |
447 | kfree_skb(skb); /* Not a KISS data frame */ | |
448 | return 0; | |
449 | } | |
450 | ||
451 | skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */ | |
452 | ||
453 | return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype); | |
454 | } |