1/* This program is free software; you can redistribute it and/or modify
2 * it under the terms of the GNU General Public License version 2
3 * as published by the Free Software Foundation.
4 *
5 * This program is distributed in the hope that it will be useful,
6 * but WITHOUT ANY WARRANTY; without even the implied warranty of
7 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
8 * GNU General Public License for more details.
9 */
10
11#include <linux/if_arp.h>
12
13#include <net/6lowpan.h>
14#include <net/ieee802154_netdev.h>
15
16#include "6lowpan_i.h"
17
18static int lowpan_give_skb_to_devices(struct sk_buff *skb,
19				      struct net_device *dev)
20{
21	struct lowpan_dev_record *entry;
22	struct sk_buff *skb_cp;
23	int stat = NET_RX_SUCCESS;
24
25	skb->protocol = htons(ETH_P_IPV6);
26	skb->pkt_type = PACKET_HOST;
27
28	rcu_read_lock();
29	list_for_each_entry_rcu(entry, &lowpan_devices, list)
30		if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
31			skb_cp = skb_copy(skb, GFP_ATOMIC);
32			if (!skb_cp) {
33				kfree_skb(skb);
34				rcu_read_unlock();
35				return NET_RX_DROP;
36			}
37
38			skb_cp->dev = entry->ldev;
39			stat = netif_rx(skb_cp);
40			if (stat == NET_RX_DROP)
41				break;
42		}
43	rcu_read_unlock();
44
45	consume_skb(skb);
46
47	return stat;
48}
49
50static int
51iphc_decompress(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
52{
53	u8 iphc0, iphc1;
54	struct ieee802154_addr_sa sa, da;
55	void *sap, *dap;
56
57	raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
58	/* at least two bytes will be used for the encoding */
59	if (skb->len < 2)
60		return -EINVAL;
61
62	if (lowpan_fetch_skb_u8(skb, &iphc0))
63		return -EINVAL;
64
65	if (lowpan_fetch_skb_u8(skb, &iphc1))
66		return -EINVAL;
67
68	ieee802154_addr_to_sa(&sa, &hdr->source);
69	ieee802154_addr_to_sa(&da, &hdr->dest);
70
71	if (sa.addr_type == IEEE802154_ADDR_SHORT)
72		sap = &sa.short_addr;
73	else
74		sap = &sa.hwaddr;
75
76	if (da.addr_type == IEEE802154_ADDR_SHORT)
77		dap = &da.short_addr;
78	else
79		dap = &da.hwaddr;
80
81	return lowpan_header_decompress(skb, skb->dev, sap, sa.addr_type,
82					IEEE802154_ADDR_LEN, dap, da.addr_type,
83					IEEE802154_ADDR_LEN, iphc0, iphc1);
84}
85
86static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
87		      struct packet_type *pt, struct net_device *orig_dev)
88{
89	struct ieee802154_hdr hdr;
90	int ret;
91
92	skb = skb_share_check(skb, GFP_ATOMIC);
93	if (!skb)
94		goto drop;
95
96	if (!netif_running(dev))
97		goto drop_skb;
98
99	if (skb->pkt_type == PACKET_OTHERHOST)
100		goto drop_skb;
101
102	if (dev->type != ARPHRD_IEEE802154)
103		goto drop_skb;
104
105	if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
106		goto drop_skb;
107
108	/* check that it's our buffer */
109	if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
110		/* Pull off the 1-byte of 6lowpan header. */
111		skb_pull(skb, 1);
112		return lowpan_give_skb_to_devices(skb, NULL);
113	} else {
114		switch (skb->data[0] & 0xe0) {
115		case LOWPAN_DISPATCH_IPHC:	/* ipv6 datagram */
116			ret = iphc_decompress(skb, &hdr);
117			if (ret < 0)
118				goto drop_skb;
119
120			return lowpan_give_skb_to_devices(skb, NULL);
121		case LOWPAN_DISPATCH_FRAG1:	/* first fragment header */
122			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
123			if (ret == 1) {
124				ret = iphc_decompress(skb, &hdr);
125				if (ret < 0)
126					goto drop_skb;
127
128				return lowpan_give_skb_to_devices(skb, NULL);
129			} else if (ret == -1) {
130				return NET_RX_DROP;
131			} else {
132				return NET_RX_SUCCESS;
133			}
134		case LOWPAN_DISPATCH_FRAGN:	/* next fragments headers */
135			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
136			if (ret == 1) {
137				ret = iphc_decompress(skb, &hdr);
138				if (ret < 0)
139					goto drop_skb;
140
141				return lowpan_give_skb_to_devices(skb, NULL);
142			} else if (ret == -1) {
143				return NET_RX_DROP;
144			} else {
145				return NET_RX_SUCCESS;
146			}
147		default:
148			break;
149		}
150	}
151
152drop_skb:
153	kfree_skb(skb);
154drop:
155	return NET_RX_DROP;
156}
157
158static struct packet_type lowpan_packet_type = {
159	.type = htons(ETH_P_IEEE802154),
160	.func = lowpan_rcv,
161};
162
163void lowpan_rx_init(void)
164{
165	dev_add_pack(&lowpan_packet_type);
166}
167
168void lowpan_rx_exit(void)
169{
170	dev_remove_pack(&lowpan_packet_type);
171}
172