xref: /linux/net/mac802154/rx.c (revision a8d70602b186f3c347e62c59a418be802b71886d)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2007-2012 Siemens AG
4  *
5  * Written by:
6  * Pavel Smolenskiy <pavel.smolenskiy@gmail.com>
7  * Maxim Gorbachyov <maxim.gorbachev@siemens.com>
8  * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
9  * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/netdevice.h>
15 #include <linux/crc-ccitt.h>
16 #include <asm/unaligned.h>
17 
18 #include <net/mac802154.h>
19 #include <net/ieee802154_netdev.h>
20 #include <net/nl802154.h>
21 
22 #include "ieee802154_i.h"
23 
24 static int ieee802154_deliver_skb(struct sk_buff *skb)
25 {
26 	skb->ip_summed = CHECKSUM_UNNECESSARY;
27 	skb->protocol = htons(ETH_P_IEEE802154);
28 
29 	return netif_receive_skb(skb);
30 }
31 
32 void mac802154_rx_beacon_worker(struct work_struct *work)
33 {
34 	struct ieee802154_local *local =
35 		container_of(work, struct ieee802154_local, rx_beacon_work);
36 	struct cfg802154_mac_pkt *mac_pkt;
37 
38 	mac_pkt = list_first_entry_or_null(&local->rx_beacon_list,
39 					   struct cfg802154_mac_pkt, node);
40 	if (!mac_pkt)
41 		return;
42 
43 	mac802154_process_beacon(local, mac_pkt->skb, mac_pkt->page, mac_pkt->channel);
44 
45 	list_del(&mac_pkt->node);
46 	kfree_skb(mac_pkt->skb);
47 	kfree(mac_pkt);
48 }
49 
50 static bool mac802154_should_answer_beacon_req(struct ieee802154_local *local)
51 {
52 	struct cfg802154_beacon_request *beacon_req;
53 	unsigned int interval;
54 
55 	rcu_read_lock();
56 	beacon_req = rcu_dereference(local->beacon_req);
57 	if (!beacon_req) {
58 		rcu_read_unlock();
59 		return false;
60 	}
61 
62 	interval = beacon_req->interval;
63 	rcu_read_unlock();
64 
65 	if (!mac802154_is_beaconing(local))
66 		return false;
67 
68 	return interval == IEEE802154_ACTIVE_SCAN_DURATION;
69 }
70 
71 void mac802154_rx_mac_cmd_worker(struct work_struct *work)
72 {
73 	struct ieee802154_local *local =
74 		container_of(work, struct ieee802154_local, rx_mac_cmd_work);
75 	struct cfg802154_mac_pkt *mac_pkt;
76 	u8 mac_cmd;
77 	int rc;
78 
79 	mac_pkt = list_first_entry_or_null(&local->rx_mac_cmd_list,
80 					   struct cfg802154_mac_pkt, node);
81 	if (!mac_pkt)
82 		return;
83 
84 	rc = ieee802154_get_mac_cmd(mac_pkt->skb, &mac_cmd);
85 	if (rc)
86 		goto out;
87 
88 	switch (mac_cmd) {
89 	case IEEE802154_CMD_BEACON_REQ:
90 		dev_dbg(&mac_pkt->sdata->dev->dev, "processing BEACON REQ\n");
91 		if (!mac802154_should_answer_beacon_req(local))
92 			break;
93 
94 		queue_delayed_work(local->mac_wq, &local->beacon_work, 0);
95 		break;
96 	default:
97 		break;
98 	}
99 
100 out:
101 	list_del(&mac_pkt->node);
102 	kfree_skb(mac_pkt->skb);
103 	kfree(mac_pkt);
104 }
105 
106 static int
107 ieee802154_subif_frame(struct ieee802154_sub_if_data *sdata,
108 		       struct sk_buff *skb, const struct ieee802154_hdr *hdr)
109 {
110 	struct wpan_phy *wpan_phy = sdata->local->hw.phy;
111 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
112 	struct cfg802154_mac_pkt *mac_pkt;
113 	__le16 span, sshort;
114 	int rc;
115 
116 	pr_debug("getting packet via slave interface %s\n", sdata->dev->name);
117 
118 	span = wpan_dev->pan_id;
119 	sshort = wpan_dev->short_addr;
120 
121 	/* Level 3 filtering: Only beacons are accepted during scans */
122 	if (sdata->required_filtering == IEEE802154_FILTERING_3_SCAN &&
123 	    sdata->required_filtering > wpan_phy->filtering) {
124 		if (mac_cb(skb)->type != IEEE802154_FC_TYPE_BEACON) {
125 			dev_dbg(&sdata->dev->dev,
126 				"drop non-beacon frame (0x%x) during scan\n",
127 				mac_cb(skb)->type);
128 			goto fail;
129 		}
130 	}
131 
132 	switch (mac_cb(skb)->dest.mode) {
133 	case IEEE802154_ADDR_NONE:
134 		if (hdr->source.mode != IEEE802154_ADDR_NONE)
135 			/* FIXME: check if we are PAN coordinator */
136 			skb->pkt_type = PACKET_OTHERHOST;
137 		else
138 			/* ACK comes with both addresses empty */
139 			skb->pkt_type = PACKET_HOST;
140 		break;
141 	case IEEE802154_ADDR_LONG:
142 		if (mac_cb(skb)->dest.pan_id != span &&
143 		    mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST))
144 			skb->pkt_type = PACKET_OTHERHOST;
145 		else if (mac_cb(skb)->dest.extended_addr == wpan_dev->extended_addr)
146 			skb->pkt_type = PACKET_HOST;
147 		else
148 			skb->pkt_type = PACKET_OTHERHOST;
149 		break;
150 	case IEEE802154_ADDR_SHORT:
151 		if (mac_cb(skb)->dest.pan_id != span &&
152 		    mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST))
153 			skb->pkt_type = PACKET_OTHERHOST;
154 		else if (mac_cb(skb)->dest.short_addr == sshort)
155 			skb->pkt_type = PACKET_HOST;
156 		else if (mac_cb(skb)->dest.short_addr ==
157 			  cpu_to_le16(IEEE802154_ADDR_BROADCAST))
158 			skb->pkt_type = PACKET_BROADCAST;
159 		else
160 			skb->pkt_type = PACKET_OTHERHOST;
161 		break;
162 	default:
163 		pr_debug("invalid dest mode\n");
164 		goto fail;
165 	}
166 
167 	skb->dev = sdata->dev;
168 
169 	/* TODO this should be moved after netif_receive_skb call, otherwise
170 	 * wireshark will show a mac header with security fields and the
171 	 * payload is already decrypted.
172 	 */
173 	rc = mac802154_llsec_decrypt(&sdata->sec, skb);
174 	if (rc) {
175 		pr_debug("decryption failed: %i\n", rc);
176 		goto fail;
177 	}
178 
179 	sdata->dev->stats.rx_packets++;
180 	sdata->dev->stats.rx_bytes += skb->len;
181 
182 	switch (mac_cb(skb)->type) {
183 	case IEEE802154_FC_TYPE_BEACON:
184 		dev_dbg(&sdata->dev->dev, "BEACON received\n");
185 		if (!mac802154_is_scanning(sdata->local))
186 			goto fail;
187 
188 		mac_pkt = kzalloc(sizeof(*mac_pkt), GFP_ATOMIC);
189 		if (!mac_pkt)
190 			goto fail;
191 
192 		mac_pkt->skb = skb_get(skb);
193 		mac_pkt->sdata = sdata;
194 		mac_pkt->page = sdata->local->scan_page;
195 		mac_pkt->channel = sdata->local->scan_channel;
196 		list_add_tail(&mac_pkt->node, &sdata->local->rx_beacon_list);
197 		queue_work(sdata->local->mac_wq, &sdata->local->rx_beacon_work);
198 		return NET_RX_SUCCESS;
199 
200 	case IEEE802154_FC_TYPE_MAC_CMD:
201 		dev_dbg(&sdata->dev->dev, "MAC COMMAND received\n");
202 		mac_pkt = kzalloc(sizeof(*mac_pkt), GFP_ATOMIC);
203 		if (!mac_pkt)
204 			goto fail;
205 
206 		mac_pkt->skb = skb_get(skb);
207 		mac_pkt->sdata = sdata;
208 		list_add_tail(&mac_pkt->node, &sdata->local->rx_mac_cmd_list);
209 		queue_work(sdata->local->mac_wq, &sdata->local->rx_mac_cmd_work);
210 		return NET_RX_SUCCESS;
211 
212 	case IEEE802154_FC_TYPE_ACK:
213 		goto fail;
214 
215 	case IEEE802154_FC_TYPE_DATA:
216 		return ieee802154_deliver_skb(skb);
217 	default:
218 		pr_warn_ratelimited("ieee802154: bad frame received "
219 				    "(type = %d)\n", mac_cb(skb)->type);
220 		goto fail;
221 	}
222 
223 fail:
224 	kfree_skb(skb);
225 	return NET_RX_DROP;
226 }
227 
228 static void
229 ieee802154_print_addr(const char *name, const struct ieee802154_addr *addr)
230 {
231 	if (addr->mode == IEEE802154_ADDR_NONE) {
232 		pr_debug("%s not present\n", name);
233 		return;
234 	}
235 
236 	pr_debug("%s PAN ID: %04x\n", name, le16_to_cpu(addr->pan_id));
237 	if (addr->mode == IEEE802154_ADDR_SHORT) {
238 		pr_debug("%s is short: %04x\n", name,
239 			 le16_to_cpu(addr->short_addr));
240 	} else {
241 		u64 hw = swab64((__force u64)addr->extended_addr);
242 
243 		pr_debug("%s is hardware: %8phC\n", name, &hw);
244 	}
245 }
246 
247 static int
248 ieee802154_parse_frame_start(struct sk_buff *skb, struct ieee802154_hdr *hdr)
249 {
250 	int hlen;
251 	struct ieee802154_mac_cb *cb = mac_cb(skb);
252 
253 	skb_reset_mac_header(skb);
254 
255 	hlen = ieee802154_hdr_pull(skb, hdr);
256 	if (hlen < 0)
257 		return -EINVAL;
258 
259 	skb->mac_len = hlen;
260 
261 	pr_debug("fc: %04x dsn: %02x\n", le16_to_cpup((__le16 *)&hdr->fc),
262 		 hdr->seq);
263 
264 	cb->type = hdr->fc.type;
265 	cb->ackreq = hdr->fc.ack_request;
266 	cb->secen = hdr->fc.security_enabled;
267 
268 	ieee802154_print_addr("destination", &hdr->dest);
269 	ieee802154_print_addr("source", &hdr->source);
270 
271 	cb->source = hdr->source;
272 	cb->dest = hdr->dest;
273 
274 	if (hdr->fc.security_enabled) {
275 		u64 key;
276 
277 		pr_debug("seclevel %i\n", hdr->sec.level);
278 
279 		switch (hdr->sec.key_id_mode) {
280 		case IEEE802154_SCF_KEY_IMPLICIT:
281 			pr_debug("implicit key\n");
282 			break;
283 
284 		case IEEE802154_SCF_KEY_INDEX:
285 			pr_debug("key %02x\n", hdr->sec.key_id);
286 			break;
287 
288 		case IEEE802154_SCF_KEY_SHORT_INDEX:
289 			pr_debug("key %04x:%04x %02x\n",
290 				 le32_to_cpu(hdr->sec.short_src) >> 16,
291 				 le32_to_cpu(hdr->sec.short_src) & 0xffff,
292 				 hdr->sec.key_id);
293 			break;
294 
295 		case IEEE802154_SCF_KEY_HW_INDEX:
296 			key = swab64((__force u64)hdr->sec.extended_src);
297 			pr_debug("key source %8phC %02x\n", &key,
298 				 hdr->sec.key_id);
299 			break;
300 		}
301 	}
302 
303 	return 0;
304 }
305 
306 static void
307 __ieee802154_rx_handle_packet(struct ieee802154_local *local,
308 			      struct sk_buff *skb)
309 {
310 	int ret;
311 	struct ieee802154_sub_if_data *sdata;
312 	struct ieee802154_hdr hdr;
313 	struct sk_buff *skb2;
314 
315 	ret = ieee802154_parse_frame_start(skb, &hdr);
316 	if (ret) {
317 		pr_debug("got invalid frame\n");
318 		return;
319 	}
320 
321 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
322 		if (sdata->wpan_dev.iftype == NL802154_IFTYPE_MONITOR)
323 			continue;
324 
325 		if (!ieee802154_sdata_running(sdata))
326 			continue;
327 
328 		/* Do not deliver packets received on interfaces expecting
329 		 * AACK=1 if the address filters where disabled.
330 		 */
331 		if (local->hw.phy->filtering < IEEE802154_FILTERING_4_FRAME_FIELDS &&
332 		    sdata->required_filtering == IEEE802154_FILTERING_4_FRAME_FIELDS)
333 			continue;
334 
335 		skb2 = skb_clone(skb, GFP_ATOMIC);
336 		if (skb2) {
337 			skb2->dev = sdata->dev;
338 			ieee802154_subif_frame(sdata, skb2, &hdr);
339 		}
340 	}
341 }
342 
343 static void
344 ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb)
345 {
346 	struct sk_buff *skb2;
347 	struct ieee802154_sub_if_data *sdata;
348 
349 	skb_reset_mac_header(skb);
350 	skb->ip_summed = CHECKSUM_UNNECESSARY;
351 	skb->pkt_type = PACKET_OTHERHOST;
352 	skb->protocol = htons(ETH_P_IEEE802154);
353 
354 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
355 		if (sdata->wpan_dev.iftype != NL802154_IFTYPE_MONITOR)
356 			continue;
357 
358 		if (!ieee802154_sdata_running(sdata))
359 			continue;
360 
361 		skb2 = skb_clone(skb, GFP_ATOMIC);
362 		if (skb2) {
363 			skb2->dev = sdata->dev;
364 			ieee802154_deliver_skb(skb2);
365 
366 			sdata->dev->stats.rx_packets++;
367 			sdata->dev->stats.rx_bytes += skb->len;
368 		}
369 	}
370 }
371 
372 void ieee802154_rx(struct ieee802154_local *local, struct sk_buff *skb)
373 {
374 	u16 crc;
375 
376 	WARN_ON_ONCE(softirq_count() == 0);
377 
378 	if (local->suspended)
379 		goto free_skb;
380 
381 	/* TODO: When a transceiver omits the checksum here, we
382 	 * add an own calculated one. This is currently an ugly
383 	 * solution because the monitor needs a crc here.
384 	 */
385 	if (local->hw.flags & IEEE802154_HW_RX_OMIT_CKSUM) {
386 		crc = crc_ccitt(0, skb->data, skb->len);
387 		put_unaligned_le16(crc, skb_put(skb, 2));
388 	}
389 
390 	rcu_read_lock();
391 
392 	ieee802154_monitors_rx(local, skb);
393 
394 	/* Level 1 filtering: Check the FCS by software when relevant */
395 	if (local->hw.phy->filtering == IEEE802154_FILTERING_NONE) {
396 		crc = crc_ccitt(0, skb->data, skb->len);
397 		if (crc)
398 			goto drop;
399 	}
400 	/* remove crc */
401 	skb_trim(skb, skb->len - 2);
402 
403 	__ieee802154_rx_handle_packet(local, skb);
404 
405 drop:
406 	rcu_read_unlock();
407 free_skb:
408 	kfree_skb(skb);
409 }
410 
411 void
412 ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi)
413 {
414 	struct ieee802154_local *local = hw_to_local(hw);
415 	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
416 
417 	cb->lqi = lqi;
418 	skb->pkt_type = IEEE802154_RX_MSG;
419 	skb_queue_tail(&local->skb_queue, skb);
420 	tasklet_schedule(&local->tasklet);
421 }
422 EXPORT_SYMBOL(ieee802154_rx_irqsafe);
423