summaryrefslogtreecommitdiffstats
path: root/net/ieee802154/6lowpan/tx.c
blob: ca53efa17be15b78db9e00372b33a9ef0911b47f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
/* This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <net/6lowpan.h>
#include <net/ndisc.h>
#include <net/ieee802154_netdev.h>
#include <net/mac802154.h>

#include "6lowpan_i.h"

#define LOWPAN_FRAG1_HEAD_SIZE	0x4
#define LOWPAN_FRAGN_HEAD_SIZE	0x5

struct lowpan_addr_info {
	struct ieee802154_addr daddr;
	struct ieee802154_addr saddr;
};

static inline struct
lowpan_addr_info *lowpan_skb_priv(const struct sk_buff *skb)
{
	WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct lowpan_addr_info));
	return (struct lowpan_addr_info *)(skb->data -
			sizeof(struct lowpan_addr_info));
}

/* This callback will be called from AF_PACKET and IPv6 stack, the AF_PACKET
 * sockets gives an 8 byte array for addresses only!
 *
 * TODO I think AF_PACKET DGRAM (sending/receiving) RAW (sending) makes no
 * sense here. We should disable it, the right use-case would be AF_INET6
 * RAW/DGRAM sockets.
 */
int lowpan_header_create(struct sk_buff *skb, struct net_device *ldev,
			 unsigned short type, const void *daddr,
			 const void *saddr, unsigned int len)
{
	struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
	struct lowpan_addr_info *info = lowpan_skb_priv(skb);
	struct lowpan_802154_neigh *llneigh = NULL;
	const struct ipv6hdr *hdr = ipv6_hdr(skb);
	struct neighbour *n;

	/* TODO:
	 * if this package isn't ipv6 one, where should it be routed?
	 */
	if (type != ETH_P_IPV6)
		return 0;

	/* intra-pan communication */
	info->saddr.pan_id = wpan_dev->pan_id;
	info->daddr.pan_id = info->saddr.pan_id;

	if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) {
		info->daddr.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
		info->daddr.mode = IEEE802154_ADDR_SHORT;
	} else {
		__le16 short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);

		n = neigh_lookup(&nd_tbl, &hdr->daddr, ldev);
		if (n) {
			llneigh = lowpan_802154_neigh(neighbour_priv(n));
			read_lock_bh(&n->lock);
			short_addr = llneigh->short_addr;
			read_unlock_bh(&n->lock);
		}

		if (llneigh &&
		    lowpan_802154_is_valid_src_short_addr(short_addr)) {
			info->daddr.short_addr = short_addr;
			info->daddr.mode = IEEE802154_ADDR_SHORT;
		} else {
			info->daddr.mode = IEEE802154_ADDR_LONG;
			ieee802154_be64_to_le64(&info->daddr.extended_addr,
						daddr);
		}

		if (n)
			neigh_release(n);
	}

	if (!saddr) {
		if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) {
			info->saddr.mode = IEEE802154_ADDR_SHORT;
			info->saddr.short_addr = wpan_dev->short_addr;
		} else {
			info->saddr.mode = IEEE802154_ADDR_LONG;
			info->saddr.extended_addr = wpan_dev->extended_addr;
		}
	} else {
		info->saddr.mode = IEEE802154_ADDR_LONG;
		ieee802154_be64_to_le64(&info->saddr.extended_addr, saddr);
	}

	return 0;
}

static struct sk_buff*
lowpan_alloc_frag(struct sk_buff *skb, int size,
		  const struct ieee802154_hdr *master_hdr, bool frag1)
{
	struct net_device *wdev = lowpan_802154_dev(skb->dev)->wdev;
	struct sk_buff *frag;
	int rc;

	frag = alloc_skb(wdev->needed_headroom + wdev->needed_tailroom + size,
			 GFP_ATOMIC);

	if (likely(frag)) {
		frag->dev = wdev;
		frag->priority = skb->priority;
		skb_reserve(frag, wdev->needed_headroom);
		skb_reset_network_header(frag);
		*mac_cb(frag) = *mac_cb(skb);

		if (frag1) {
			skb_put_data(frag, skb_mac_header(skb), skb->mac_len);
		} else {
			rc = wpan_dev_hard_header(frag, wdev,
						  &master_hdr->dest,
						  &master_hdr->source, size);
			if (rc < 0) {
				kfree_skb(frag);
				return ERR_PTR(rc);
			}
		}
	} else {
		frag = ERR_PTR(-ENOMEM);
	}

	return frag;
}

static int
lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr,
		     u8 *frag_hdr, int frag_hdrlen,
		     int offset, int len, bool frag1)
{
	struct sk_buff *frag;

	raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen);

	frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr, frag1);
	if (IS_ERR(frag))
		return PTR_ERR(frag);

	skb_put_data(frag, frag_hdr, frag_hdrlen);
	skb_put_data(frag, skb_network_header(skb) + offset, len);

	raw_dump_table(__func__, " fragment dump", frag->data, frag->len);

	return dev_queue_xmit(frag);
}

static int
lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *ldev,
		       const struct ieee802154_hdr *wpan_hdr, u16 dgram_size,
		       u16 dgram_offset)
{
	__be16 frag_tag;
	u8 frag_hdr[5];
	int frag_cap, frag_len, payload_cap, rc;
	int skb_unprocessed, skb_offset;

	frag_tag = htons(lowpan_802154_dev(ldev)->fragment_tag);
	lowpan_802154_dev(ldev)->fragment_tag++;

	frag_hdr[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x07);
	frag_hdr[1] = dgram_size & 0xff;
	memcpy(frag_hdr + 2, &frag_tag, sizeof(frag_tag));

	payload_cap = ieee802154_max_payload(wpan_hdr);

	frag_len = round_down(payload_cap - LOWPAN_FRAG1_HEAD_SIZE -
			      skb_network_header_len(skb), 8);

	skb_offset = skb_network_header_len(skb);
	skb_unprocessed = skb->len - skb->mac_len - skb_offset;

	rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
				  LOWPAN_FRAG1_HEAD_SIZE, 0,
				  frag_len + skb_network_header_len(skb),
				  true);
	if (rc) {
		pr_debug("%s unable to send FRAG1 packet (tag: %d)",
			 __func__, ntohs(frag_tag));
		goto err;
	}

	frag_hdr[0] &= ~LOWPAN_DISPATCH_FRAG1;
	frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN;
	frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8);

	do {
		dgram_offset += frag_len;
		skb_offset += frag_len;
		skb_unprocessed -= frag_len;
		frag_len = min(frag_cap, skb_unprocessed);

		frag_hdr[4] = dgram_offset >> 3;

		rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
					  LOWPAN_FRAGN_HEAD_SIZE, skb_offset,
					  frag_len, false);
		if (rc) {
			pr_debug("%s unable to send a FRAGN packet. (tag: %d, offset: %d)\n",
				 __func__, ntohs(frag_tag), skb_offset);
			goto err;
		}
	} while (skb_unprocessed > frag_cap);

	ldev->stats.tx_packets++;
	ldev->stats.tx_bytes += dgram_size;
	consume_skb(skb);
	return NET_XMIT_SUCCESS;

err:
	kfree_skb(skb);
	return rc;
}

static int lowpan_header(struct sk_buff *skb, struct net_device *ldev,
			 u16 *dgram_size, u16 *dgram_offset)
{
	struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
	struct lowpan_addr_info info;

	memcpy(&info, lowpan_skb_priv(skb), sizeof(info));

	*dgram_size = skb->len;
	lowpan_header_compress(skb, ldev, &info.daddr, &info.saddr);
	/* dgram_offset = (saved bytes after compression) + lowpan header len */
	*dgram_offset = (*dgram_size - skb->len) + skb_network_header_len(skb);

	cb->type = IEEE802154_FC_TYPE_DATA;

	if (info.daddr.mode == IEEE802154_ADDR_SHORT &&
	    ieee802154_is_broadcast_short_addr(info.daddr.short_addr))
		cb->ackreq = false;
	else
		cb->ackreq = wpan_dev->ackreq;

	return wpan_dev_hard_header(skb, lowpan_802154_dev(ldev)->wdev,
				    &info.daddr, &info.saddr, 0);
}

netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev)
{
	struct ieee802154_hdr wpan_hdr;
	int max_single, ret;
	u16 dgram_size, dgram_offset;

	pr_debug("package xmit\n");

	WARN_ON_ONCE(skb->len > IPV6_MIN_MTU);

	/* We must take a copy of the skb before we modify/replace the ipv6
	 * header as the header could be used elsewhere
	 */
	if (unlikely(skb_headroom(skb) < ldev->needed_headroom ||
		     skb_tailroom(skb) < ldev->needed_tailroom)) {
		struct sk_buff *nskb;

		nskb = skb_copy_expand(skb, ldev->needed_headroom,
				       ldev->needed_tailroom, GFP_ATOMIC);
		if (likely(nskb)) {
			consume_skb(skb);
			skb = nskb;
		} else {
			kfree_skb(skb);
			return NET_XMIT_DROP;
		}
	} else {
		skb = skb_unshare(skb, GFP_ATOMIC);
		if (!skb)
			return NET_XMIT_DROP;
	}

	ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset);
	if (ret < 0) {
		kfree_skb(skb);
		return NET_XMIT_DROP;
	}

	if (ieee802154_hdr_peek(skb, &wpan_hdr) < 0) {
		kfree_skb(skb);
		return NET_XMIT_DROP;
	}

	max_single = ieee802154_max_payload(&wpan_hdr);

	if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) {
		skb->dev = lowpan_802154_dev(ldev)->wdev;
		ldev->stats.tx_packets++;
		ldev->stats.tx_bytes += dgram_size;
		return dev_queue_xmit(skb);
	} else {
		netdev_tx_t rc;

		pr_debug("frame is too big, fragmentation is needed\n");
		rc = lowpan_xmit_fragmented(skb, ldev, &wpan_hdr, dgram_size,
					    dgram_offset);

		return rc < 0 ? NET_XMIT_DROP : rc;
	}
}