1/*
2 * Copyright (C) 2007-2012 Siemens AG
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2
6 * as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * GNU General Public License for more details.
12 *
13 * Written by:
14 * Pavel Smolenskiy <pavel.smolenskiy@gmail.com>
15 * Maxim Gorbachyov <maxim.gorbachev@siemens.com>
16 * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
17 * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
18 */
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/netdevice.h>
23#include <linux/crc-ccitt.h>
24#include <asm/unaligned.h>
25
26#include <net/mac802154.h>
27#include <net/ieee802154_netdev.h>
28#include <net/nl802154.h>
29
30#include "ieee802154_i.h"
31
32static int ieee802154_deliver_skb(struct sk_buff *skb)
33{
34	skb->ip_summed = CHECKSUM_UNNECESSARY;
35	skb->protocol = htons(ETH_P_IEEE802154);
36
37	return netif_receive_skb(skb);
38}
39
40static int
41ieee802154_subif_frame(struct ieee802154_sub_if_data *sdata,
42		       struct sk_buff *skb, const struct ieee802154_hdr *hdr)
43{
44	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
45	__le16 span, sshort;
46	int rc;
47
48	pr_debug("getting packet via slave interface %s\n", sdata->dev->name);
49
50	span = wpan_dev->pan_id;
51	sshort = wpan_dev->short_addr;
52
53	switch (mac_cb(skb)->dest.mode) {
54	case IEEE802154_ADDR_NONE:
55		if (mac_cb(skb)->dest.mode != IEEE802154_ADDR_NONE)
56			/* FIXME: check if we are PAN coordinator */
57			skb->pkt_type = PACKET_OTHERHOST;
58		else
59			/* ACK comes with both addresses empty */
60			skb->pkt_type = PACKET_HOST;
61		break;
62	case IEEE802154_ADDR_LONG:
63		if (mac_cb(skb)->dest.pan_id != span &&
64		    mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST))
65			skb->pkt_type = PACKET_OTHERHOST;
66		else if (mac_cb(skb)->dest.extended_addr == wpan_dev->extended_addr)
67			skb->pkt_type = PACKET_HOST;
68		else
69			skb->pkt_type = PACKET_OTHERHOST;
70		break;
71	case IEEE802154_ADDR_SHORT:
72		if (mac_cb(skb)->dest.pan_id != span &&
73		    mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST))
74			skb->pkt_type = PACKET_OTHERHOST;
75		else if (mac_cb(skb)->dest.short_addr == sshort)
76			skb->pkt_type = PACKET_HOST;
77		else if (mac_cb(skb)->dest.short_addr ==
78			  cpu_to_le16(IEEE802154_ADDR_BROADCAST))
79			skb->pkt_type = PACKET_BROADCAST;
80		else
81			skb->pkt_type = PACKET_OTHERHOST;
82		break;
83	default:
84		pr_debug("invalid dest mode\n");
85		goto fail;
86	}
87
88	skb->dev = sdata->dev;
89
90	/* TODO this should be moved after netif_receive_skb call, otherwise
91	 * wireshark will show a mac header with security fields and the
92	 * payload is already decrypted.
93	 */
94	rc = mac802154_llsec_decrypt(&sdata->sec, skb);
95	if (rc) {
96		pr_debug("decryption failed: %i\n", rc);
97		goto fail;
98	}
99
100	sdata->dev->stats.rx_packets++;
101	sdata->dev->stats.rx_bytes += skb->len;
102
103	switch (mac_cb(skb)->type) {
104	case IEEE802154_FC_TYPE_DATA:
105		return ieee802154_deliver_skb(skb);
106	default:
107		pr_warn("ieee802154: bad frame received (type = %d)\n",
108			mac_cb(skb)->type);
109		goto fail;
110	}
111
112fail:
113	kfree_skb(skb);
114	return NET_RX_DROP;
115}
116
117static void
118ieee802154_print_addr(const char *name, const struct ieee802154_addr *addr)
119{
120	if (addr->mode == IEEE802154_ADDR_NONE)
121		pr_debug("%s not present\n", name);
122
123	pr_debug("%s PAN ID: %04x\n", name, le16_to_cpu(addr->pan_id));
124	if (addr->mode == IEEE802154_ADDR_SHORT) {
125		pr_debug("%s is short: %04x\n", name,
126			 le16_to_cpu(addr->short_addr));
127	} else {
128		u64 hw = swab64((__force u64)addr->extended_addr);
129
130		pr_debug("%s is hardware: %8phC\n", name, &hw);
131	}
132}
133
134static int
135ieee802154_parse_frame_start(struct sk_buff *skb, struct ieee802154_hdr *hdr)
136{
137	int hlen;
138	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
139
140	skb_reset_mac_header(skb);
141
142	hlen = ieee802154_hdr_pull(skb, hdr);
143	if (hlen < 0)
144		return -EINVAL;
145
146	skb->mac_len = hlen;
147
148	pr_debug("fc: %04x dsn: %02x\n", le16_to_cpup((__le16 *)&hdr->fc),
149		 hdr->seq);
150
151	cb->type = hdr->fc.type;
152	cb->ackreq = hdr->fc.ack_request;
153	cb->secen = hdr->fc.security_enabled;
154
155	ieee802154_print_addr("destination", &hdr->dest);
156	ieee802154_print_addr("source", &hdr->source);
157
158	cb->source = hdr->source;
159	cb->dest = hdr->dest;
160
161	if (hdr->fc.security_enabled) {
162		u64 key;
163
164		pr_debug("seclevel %i\n", hdr->sec.level);
165
166		switch (hdr->sec.key_id_mode) {
167		case IEEE802154_SCF_KEY_IMPLICIT:
168			pr_debug("implicit key\n");
169			break;
170
171		case IEEE802154_SCF_KEY_INDEX:
172			pr_debug("key %02x\n", hdr->sec.key_id);
173			break;
174
175		case IEEE802154_SCF_KEY_SHORT_INDEX:
176			pr_debug("key %04x:%04x %02x\n",
177				 le32_to_cpu(hdr->sec.short_src) >> 16,
178				 le32_to_cpu(hdr->sec.short_src) & 0xffff,
179				 hdr->sec.key_id);
180			break;
181
182		case IEEE802154_SCF_KEY_HW_INDEX:
183			key = swab64((__force u64)hdr->sec.extended_src);
184			pr_debug("key source %8phC %02x\n", &key,
185				 hdr->sec.key_id);
186			break;
187		}
188	}
189
190	return 0;
191}
192
193static void
194__ieee802154_rx_handle_packet(struct ieee802154_local *local,
195			      struct sk_buff *skb)
196{
197	int ret;
198	struct ieee802154_sub_if_data *sdata;
199	struct ieee802154_hdr hdr;
200
201	ret = ieee802154_parse_frame_start(skb, &hdr);
202	if (ret) {
203		pr_debug("got invalid frame\n");
204		kfree_skb(skb);
205		return;
206	}
207
208	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
209		if (sdata->wpan_dev.iftype != NL802154_IFTYPE_NODE)
210			continue;
211
212		if (!ieee802154_sdata_running(sdata))
213			continue;
214
215		ieee802154_subif_frame(sdata, skb, &hdr);
216		skb = NULL;
217		break;
218	}
219
220	if (skb)
221		kfree_skb(skb);
222}
223
224static void
225ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb)
226{
227	struct sk_buff *skb2;
228	struct ieee802154_sub_if_data *sdata;
229
230	skb_reset_mac_header(skb);
231	skb->ip_summed = CHECKSUM_UNNECESSARY;
232	skb->pkt_type = PACKET_OTHERHOST;
233	skb->protocol = htons(ETH_P_IEEE802154);
234
235	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
236		if (sdata->wpan_dev.iftype != NL802154_IFTYPE_MONITOR)
237			continue;
238
239		if (!ieee802154_sdata_running(sdata))
240			continue;
241
242		skb2 = skb_clone(skb, GFP_ATOMIC);
243		if (skb2) {
244			skb2->dev = sdata->dev;
245			ieee802154_deliver_skb(skb2);
246
247			sdata->dev->stats.rx_packets++;
248			sdata->dev->stats.rx_bytes += skb->len;
249		}
250	}
251}
252
253void ieee802154_rx(struct ieee802154_local *local, struct sk_buff *skb)
254{
255	u16 crc;
256
257	WARN_ON_ONCE(softirq_count() == 0);
258
259	if (local->suspended)
260		goto drop;
261
262	/* TODO: When a transceiver omits the checksum here, we
263	 * add an own calculated one. This is currently an ugly
264	 * solution because the monitor needs a crc here.
265	 */
266	if (local->hw.flags & IEEE802154_HW_RX_OMIT_CKSUM) {
267		crc = crc_ccitt(0, skb->data, skb->len);
268		put_unaligned_le16(crc, skb_put(skb, 2));
269	}
270
271	rcu_read_lock();
272
273	ieee802154_monitors_rx(local, skb);
274
275	/* Check if transceiver doesn't validate the checksum.
276	 * If not we validate the checksum here.
277	 */
278	if (local->hw.flags & IEEE802154_HW_RX_DROP_BAD_CKSUM) {
279		crc = crc_ccitt(0, skb->data, skb->len);
280		if (crc) {
281			rcu_read_unlock();
282			goto drop;
283		}
284	}
285	/* remove crc */
286	skb_trim(skb, skb->len - 2);
287
288	__ieee802154_rx_handle_packet(local, skb);
289
290	rcu_read_unlock();
291
292	return;
293drop:
294	kfree_skb(skb);
295}
296
297void
298ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi)
299{
300	struct ieee802154_local *local = hw_to_local(hw);
301
302	mac_cb(skb)->lqi = lqi;
303	skb->pkt_type = IEEE802154_RX_MSG;
304	skb_queue_tail(&local->skb_queue, skb);
305	tasklet_schedule(&local->tasklet);
306}
307EXPORT_SYMBOL(ieee802154_rx_irqsafe);
308