xref: /openbmc/linux/net/mac802154/rx.c (revision e2f1cf25)
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 
32 static 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 
40 static int
41 ieee802154_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 	rc = mac802154_llsec_decrypt(&sdata->sec, skb);
91 	if (rc) {
92 		pr_debug("decryption failed: %i\n", rc);
93 		goto fail;
94 	}
95 
96 	sdata->dev->stats.rx_packets++;
97 	sdata->dev->stats.rx_bytes += skb->len;
98 
99 	switch (mac_cb(skb)->type) {
100 	case IEEE802154_FC_TYPE_DATA:
101 		return ieee802154_deliver_skb(skb);
102 	default:
103 		pr_warn("ieee802154: bad frame received (type = %d)\n",
104 			mac_cb(skb)->type);
105 		goto fail;
106 	}
107 
108 fail:
109 	kfree_skb(skb);
110 	return NET_RX_DROP;
111 }
112 
113 static void
114 ieee802154_print_addr(const char *name, const struct ieee802154_addr *addr)
115 {
116 	if (addr->mode == IEEE802154_ADDR_NONE)
117 		pr_debug("%s not present\n", name);
118 
119 	pr_debug("%s PAN ID: %04x\n", name, le16_to_cpu(addr->pan_id));
120 	if (addr->mode == IEEE802154_ADDR_SHORT) {
121 		pr_debug("%s is short: %04x\n", name,
122 			 le16_to_cpu(addr->short_addr));
123 	} else {
124 		u64 hw = swab64((__force u64)addr->extended_addr);
125 
126 		pr_debug("%s is hardware: %8phC\n", name, &hw);
127 	}
128 }
129 
130 static int
131 ieee802154_parse_frame_start(struct sk_buff *skb, struct ieee802154_hdr *hdr)
132 {
133 	int hlen;
134 	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
135 
136 	skb_reset_mac_header(skb);
137 
138 	hlen = ieee802154_hdr_pull(skb, hdr);
139 	if (hlen < 0)
140 		return -EINVAL;
141 
142 	skb->mac_len = hlen;
143 
144 	pr_debug("fc: %04x dsn: %02x\n", le16_to_cpup((__le16 *)&hdr->fc),
145 		 hdr->seq);
146 
147 	cb->type = hdr->fc.type;
148 	cb->ackreq = hdr->fc.ack_request;
149 	cb->secen = hdr->fc.security_enabled;
150 
151 	ieee802154_print_addr("destination", &hdr->dest);
152 	ieee802154_print_addr("source", &hdr->source);
153 
154 	cb->source = hdr->source;
155 	cb->dest = hdr->dest;
156 
157 	if (hdr->fc.security_enabled) {
158 		u64 key;
159 
160 		pr_debug("seclevel %i\n", hdr->sec.level);
161 
162 		switch (hdr->sec.key_id_mode) {
163 		case IEEE802154_SCF_KEY_IMPLICIT:
164 			pr_debug("implicit key\n");
165 			break;
166 
167 		case IEEE802154_SCF_KEY_INDEX:
168 			pr_debug("key %02x\n", hdr->sec.key_id);
169 			break;
170 
171 		case IEEE802154_SCF_KEY_SHORT_INDEX:
172 			pr_debug("key %04x:%04x %02x\n",
173 				 le32_to_cpu(hdr->sec.short_src) >> 16,
174 				 le32_to_cpu(hdr->sec.short_src) & 0xffff,
175 				 hdr->sec.key_id);
176 			break;
177 
178 		case IEEE802154_SCF_KEY_HW_INDEX:
179 			key = swab64((__force u64)hdr->sec.extended_src);
180 			pr_debug("key source %8phC %02x\n", &key,
181 				 hdr->sec.key_id);
182 			break;
183 		}
184 	}
185 
186 	return 0;
187 }
188 
189 static void
190 __ieee802154_rx_handle_packet(struct ieee802154_local *local,
191 			      struct sk_buff *skb)
192 {
193 	int ret;
194 	struct ieee802154_sub_if_data *sdata;
195 	struct ieee802154_hdr hdr;
196 
197 	ret = ieee802154_parse_frame_start(skb, &hdr);
198 	if (ret) {
199 		pr_debug("got invalid frame\n");
200 		kfree_skb(skb);
201 		return;
202 	}
203 
204 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
205 		if (sdata->wpan_dev.iftype != NL802154_IFTYPE_NODE)
206 			continue;
207 
208 		if (!ieee802154_sdata_running(sdata))
209 			continue;
210 
211 		ieee802154_subif_frame(sdata, skb, &hdr);
212 		skb = NULL;
213 		break;
214 	}
215 
216 	if (skb)
217 		kfree_skb(skb);
218 }
219 
220 static void
221 ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb)
222 {
223 	struct sk_buff *skb2;
224 	struct ieee802154_sub_if_data *sdata;
225 
226 	skb_reset_mac_header(skb);
227 	skb->ip_summed = CHECKSUM_UNNECESSARY;
228 	skb->pkt_type = PACKET_OTHERHOST;
229 	skb->protocol = htons(ETH_P_IEEE802154);
230 
231 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
232 		if (sdata->wpan_dev.iftype != NL802154_IFTYPE_MONITOR)
233 			continue;
234 
235 		if (!ieee802154_sdata_running(sdata))
236 			continue;
237 
238 		skb2 = skb_clone(skb, GFP_ATOMIC);
239 		if (skb2) {
240 			skb2->dev = sdata->dev;
241 			ieee802154_deliver_skb(skb2);
242 
243 			sdata->dev->stats.rx_packets++;
244 			sdata->dev->stats.rx_bytes += skb->len;
245 		}
246 	}
247 }
248 
249 void ieee802154_rx(struct ieee802154_hw *hw, struct sk_buff *skb)
250 {
251 	struct ieee802154_local *local = hw_to_local(hw);
252 	u16 crc;
253 
254 	WARN_ON_ONCE(softirq_count() == 0);
255 
256 	/* TODO: When a transceiver omits the checksum here, we
257 	 * add an own calculated one. This is currently an ugly
258 	 * solution because the monitor needs a crc here.
259 	 */
260 	if (local->hw.flags & IEEE802154_HW_RX_OMIT_CKSUM) {
261 		crc = crc_ccitt(0, skb->data, skb->len);
262 		put_unaligned_le16(crc, skb_put(skb, 2));
263 	}
264 
265 	rcu_read_lock();
266 
267 	ieee802154_monitors_rx(local, skb);
268 
269 	/* Check if transceiver doesn't validate the checksum.
270 	 * If not we validate the checksum here.
271 	 */
272 	if (local->hw.flags & IEEE802154_HW_RX_DROP_BAD_CKSUM) {
273 		crc = crc_ccitt(0, skb->data, skb->len);
274 		if (crc) {
275 			rcu_read_unlock();
276 			kfree_skb(skb);
277 			return;
278 		}
279 	}
280 	/* remove crc */
281 	skb_trim(skb, skb->len - 2);
282 
283 	__ieee802154_rx_handle_packet(local, skb);
284 
285 	rcu_read_unlock();
286 }
287 EXPORT_SYMBOL(ieee802154_rx);
288 
289 void
290 ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi)
291 {
292 	struct ieee802154_local *local = hw_to_local(hw);
293 
294 	mac_cb(skb)->lqi = lqi;
295 	skb->pkt_type = IEEE802154_RX_MSG;
296 	skb_queue_tail(&local->skb_queue, skb);
297 	tasklet_schedule(&local->tasklet);
298 }
299 EXPORT_SYMBOL(ieee802154_rx_irqsafe);
300