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	spin_lock_bh(&sdata->mib_lock);
51
52	span = wpan_dev->pan_id;
53	sshort = wpan_dev->short_addr;
54
55	switch (mac_cb(skb)->dest.mode) {
56	case IEEE802154_ADDR_NONE:
57		if (mac_cb(skb)->dest.mode != IEEE802154_ADDR_NONE)
58			/* FIXME: check if we are PAN coordinator */
59			skb->pkt_type = PACKET_OTHERHOST;
60		else
61			/* ACK comes with both addresses empty */
62			skb->pkt_type = PACKET_HOST;
63		break;
64	case IEEE802154_ADDR_LONG:
65		if (mac_cb(skb)->dest.pan_id != span &&
66		    mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST))
67			skb->pkt_type = PACKET_OTHERHOST;
68		else if (mac_cb(skb)->dest.extended_addr == wpan_dev->extended_addr)
69			skb->pkt_type = PACKET_HOST;
70		else
71			skb->pkt_type = PACKET_OTHERHOST;
72		break;
73	case IEEE802154_ADDR_SHORT:
74		if (mac_cb(skb)->dest.pan_id != span &&
75		    mac_cb(skb)->dest.pan_id != cpu_to_le16(IEEE802154_PANID_BROADCAST))
76			skb->pkt_type = PACKET_OTHERHOST;
77		else if (mac_cb(skb)->dest.short_addr == sshort)
78			skb->pkt_type = PACKET_HOST;
79		else if (mac_cb(skb)->dest.short_addr ==
80			  cpu_to_le16(IEEE802154_ADDR_BROADCAST))
81			skb->pkt_type = PACKET_BROADCAST;
82		else
83			skb->pkt_type = PACKET_OTHERHOST;
84		break;
85	default:
86		spin_unlock_bh(&sdata->mib_lock);
87		pr_debug("invalid dest mode\n");
88		goto fail;
89	}
90
91	spin_unlock_bh(&sdata->mib_lock);
92
93	skb->dev = sdata->dev;
94
95	rc = mac802154_llsec_decrypt(&sdata->sec, skb);
96	if (rc) {
97		pr_debug("decryption failed: %i\n", rc);
98		goto fail;
99	}
100
101	sdata->dev->stats.rx_packets++;
102	sdata->dev->stats.rx_bytes += skb->len;
103
104	switch (mac_cb(skb)->type) {
105	case IEEE802154_FC_TYPE_DATA:
106		return ieee802154_deliver_skb(skb);
107	default:
108		pr_warn("ieee802154: bad frame received (type = %d)\n",
109			mac_cb(skb)->type);
110		goto fail;
111	}
112
113fail:
114	kfree_skb(skb);
115	return NET_RX_DROP;
116}
117
118static void
119ieee802154_print_addr(const char *name, const struct ieee802154_addr *addr)
120{
121	if (addr->mode == IEEE802154_ADDR_NONE)
122		pr_debug("%s not present\n", name);
123
124	pr_debug("%s PAN ID: %04x\n", name, le16_to_cpu(addr->pan_id));
125	if (addr->mode == IEEE802154_ADDR_SHORT) {
126		pr_debug("%s is short: %04x\n", name,
127			 le16_to_cpu(addr->short_addr));
128	} else {
129		u64 hw = swab64((__force u64)addr->extended_addr);
130
131		pr_debug("%s is hardware: %8phC\n", name, &hw);
132	}
133}
134
135static int
136ieee802154_parse_frame_start(struct sk_buff *skb, struct ieee802154_hdr *hdr)
137{
138	int hlen;
139	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
140
141	skb_reset_mac_header(skb);
142
143	hlen = ieee802154_hdr_pull(skb, hdr);
144	if (hlen < 0)
145		return -EINVAL;
146
147	skb->mac_len = hlen;
148
149	pr_debug("fc: %04x dsn: %02x\n", le16_to_cpup((__le16 *)&hdr->fc),
150		 hdr->seq);
151
152	cb->type = hdr->fc.type;
153	cb->ackreq = hdr->fc.ack_request;
154	cb->secen = hdr->fc.security_enabled;
155
156	ieee802154_print_addr("destination", &hdr->dest);
157	ieee802154_print_addr("source", &hdr->source);
158
159	cb->source = hdr->source;
160	cb->dest = hdr->dest;
161
162	if (hdr->fc.security_enabled) {
163		u64 key;
164
165		pr_debug("seclevel %i\n", hdr->sec.level);
166
167		switch (hdr->sec.key_id_mode) {
168		case IEEE802154_SCF_KEY_IMPLICIT:
169			pr_debug("implicit key\n");
170			break;
171
172		case IEEE802154_SCF_KEY_INDEX:
173			pr_debug("key %02x\n", hdr->sec.key_id);
174			break;
175
176		case IEEE802154_SCF_KEY_SHORT_INDEX:
177			pr_debug("key %04x:%04x %02x\n",
178				 le32_to_cpu(hdr->sec.short_src) >> 16,
179				 le32_to_cpu(hdr->sec.short_src) & 0xffff,
180				 hdr->sec.key_id);
181			break;
182
183		case IEEE802154_SCF_KEY_HW_INDEX:
184			key = swab64((__force u64)hdr->sec.extended_src);
185			pr_debug("key source %8phC %02x\n", &key,
186				 hdr->sec.key_id);
187			break;
188		}
189	}
190
191	return 0;
192}
193
194static void
195__ieee802154_rx_handle_packet(struct ieee802154_local *local,
196			      struct sk_buff *skb)
197{
198	int ret;
199	struct ieee802154_sub_if_data *sdata;
200	struct ieee802154_hdr hdr;
201
202	ret = ieee802154_parse_frame_start(skb, &hdr);
203	if (ret) {
204		pr_debug("got invalid frame\n");
205		kfree_skb(skb);
206		return;
207	}
208
209	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
210		if (sdata->vif.type != NL802154_IFTYPE_NODE ||
211		    !netif_running(sdata->dev))
212			continue;
213
214		ieee802154_subif_frame(sdata, skb, &hdr);
215		skb = NULL;
216		break;
217	}
218
219	if (skb)
220		kfree_skb(skb);
221}
222
223static void
224ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb)
225{
226	struct sk_buff *skb2;
227	struct ieee802154_sub_if_data *sdata;
228
229	skb_reset_mac_header(skb);
230	skb->ip_summed = CHECKSUM_UNNECESSARY;
231	skb->pkt_type = PACKET_OTHERHOST;
232	skb->protocol = htons(ETH_P_IEEE802154);
233
234	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
235		if (sdata->vif.type != NL802154_IFTYPE_MONITOR)
236			continue;
237
238		if (!ieee802154_sdata_running(sdata))
239			continue;
240
241		skb2 = skb_clone(skb, GFP_ATOMIC);
242		if (skb2) {
243			skb2->dev = sdata->dev;
244			ieee802154_deliver_skb(skb2);
245
246			sdata->dev->stats.rx_packets++;
247			sdata->dev->stats.rx_bytes += skb->len;
248		}
249	}
250}
251
252void ieee802154_rx(struct ieee802154_hw *hw, struct sk_buff *skb)
253{
254	struct ieee802154_local *local = hw_to_local(hw);
255	u16 crc;
256
257	WARN_ON_ONCE(softirq_count() == 0);
258
259	/* TODO: When a transceiver omits the checksum here, we
260	 * add an own calculated one. This is currently an ugly
261	 * solution because the monitor needs a crc here.
262	 */
263	if (local->hw.flags & IEEE802154_HW_RX_OMIT_CKSUM) {
264		crc = crc_ccitt(0, skb->data, skb->len);
265		put_unaligned_le16(crc, skb_put(skb, 2));
266	}
267
268	rcu_read_lock();
269
270	ieee802154_monitors_rx(local, skb);
271
272	/* Check if transceiver doesn't validate the checksum.
273	 * If not we validate the checksum here.
274	 */
275	if (local->hw.flags & IEEE802154_HW_RX_DROP_BAD_CKSUM) {
276		crc = crc_ccitt(0, skb->data, skb->len);
277		if (crc) {
278			rcu_read_unlock();
279			kfree_skb(skb);
280			return;
281		}
282	}
283	/* remove crc */
284	skb_trim(skb, skb->len - 2);
285
286	__ieee802154_rx_handle_packet(local, skb);
287
288	rcu_read_unlock();
289}
290EXPORT_SYMBOL(ieee802154_rx);
291
292void
293ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi)
294{
295	struct ieee802154_local *local = hw_to_local(hw);
296
297	mac_cb(skb)->lqi = lqi;
298	skb->pkt_type = IEEE802154_RX_MSG;
299	skb_queue_tail(&local->skb_queue, skb);
300	tasklet_schedule(&local->tasklet);
301}
302EXPORT_SYMBOL(ieee802154_rx_irqsafe);
303