1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * Authors:
5 * (C) 2016 Pengutronix, Alexander Aring <aar@pengutronix.de>
6 */
7
8#include <net/6lowpan.h>
9#include <net/addrconf.h>
10#include <net/ndisc.h>
11
12#include "6lowpan_i.h"
13
14static int lowpan_ndisc_is_useropt(u8 nd_opt_type)
15{
16	return nd_opt_type == ND_OPT_6CO;
17}
18
19#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
20#define NDISC_802154_SHORT_ADDR_LENGTH	1
21static int lowpan_ndisc_parse_802154_options(const struct net_device *dev,
22					     struct nd_opt_hdr *nd_opt,
23					     struct ndisc_options *ndopts)
24{
25	switch (nd_opt->nd_opt_len) {
26	case NDISC_802154_SHORT_ADDR_LENGTH:
27		if (ndopts->nd_802154_opt_array[nd_opt->nd_opt_type])
28			ND_PRINTK(2, warn,
29				  "%s: duplicated short addr ND6 option found: type=%d\n",
30				  __func__, nd_opt->nd_opt_type);
31		else
32			ndopts->nd_802154_opt_array[nd_opt->nd_opt_type] = nd_opt;
33		return 1;
34	default:
35		/* all others will be handled by ndisc IPv6 option parsing */
36		return 0;
37	}
38}
39
40static int lowpan_ndisc_parse_options(const struct net_device *dev,
41				      struct nd_opt_hdr *nd_opt,
42				      struct ndisc_options *ndopts)
43{
44	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
45		return 0;
46
47	switch (nd_opt->nd_opt_type) {
48	case ND_OPT_SOURCE_LL_ADDR:
49	case ND_OPT_TARGET_LL_ADDR:
50		return lowpan_ndisc_parse_802154_options(dev, nd_opt, ndopts);
51	default:
52		return 0;
53	}
54}
55
56static void lowpan_ndisc_802154_update(struct neighbour *n, u32 flags,
57				       u8 icmp6_type,
58				       const struct ndisc_options *ndopts)
59{
60	struct lowpan_802154_neigh *neigh = lowpan_802154_neigh(neighbour_priv(n));
61	u8 *lladdr_short = NULL;
62
63	switch (icmp6_type) {
64	case NDISC_ROUTER_SOLICITATION:
65	case NDISC_ROUTER_ADVERTISEMENT:
66	case NDISC_NEIGHBOUR_SOLICITATION:
67		if (ndopts->nd_802154_opts_src_lladdr) {
68			lladdr_short = __ndisc_opt_addr_data(ndopts->nd_802154_opts_src_lladdr,
69							     IEEE802154_SHORT_ADDR_LEN, 0);
70			if (!lladdr_short) {
71				ND_PRINTK(2, warn,
72					  "NA: invalid short link-layer address length\n");
73				return;
74			}
75		}
76		break;
77	case NDISC_REDIRECT:
78	case NDISC_NEIGHBOUR_ADVERTISEMENT:
79		if (ndopts->nd_802154_opts_tgt_lladdr) {
80			lladdr_short = __ndisc_opt_addr_data(ndopts->nd_802154_opts_tgt_lladdr,
81							     IEEE802154_SHORT_ADDR_LEN, 0);
82			if (!lladdr_short) {
83				ND_PRINTK(2, warn,
84					  "NA: invalid short link-layer address length\n");
85				return;
86			}
87		}
88		break;
89	default:
90		break;
91	}
92
93	write_lock_bh(&n->lock);
94	if (lladdr_short) {
95		ieee802154_be16_to_le16(&neigh->short_addr, lladdr_short);
96		if (!lowpan_802154_is_valid_src_short_addr(neigh->short_addr))
97			neigh->short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
98	}
99	write_unlock_bh(&n->lock);
100}
101
102static void lowpan_ndisc_update(const struct net_device *dev,
103				struct neighbour *n, u32 flags, u8 icmp6_type,
104				const struct ndisc_options *ndopts)
105{
106	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
107		return;
108
109	/* react on overrides only. TODO check if this is really right. */
110	if (flags & NEIGH_UPDATE_F_OVERRIDE)
111		lowpan_ndisc_802154_update(n, flags, icmp6_type, ndopts);
112}
113
114static int lowpan_ndisc_opt_addr_space(const struct net_device *dev,
115				       u8 icmp6_type, struct neighbour *neigh,
116				       u8 *ha_buf, u8 **ha)
117{
118	struct lowpan_802154_neigh *n;
119	struct wpan_dev *wpan_dev;
120	int addr_space = 0;
121
122	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
123		return 0;
124
125	switch (icmp6_type) {
126	case NDISC_REDIRECT:
127		n = lowpan_802154_neigh(neighbour_priv(neigh));
128
129		read_lock_bh(&neigh->lock);
130		if (lowpan_802154_is_valid_src_short_addr(n->short_addr)) {
131			memcpy(ha_buf, &n->short_addr,
132			       IEEE802154_SHORT_ADDR_LEN);
133			read_unlock_bh(&neigh->lock);
134			addr_space += __ndisc_opt_addr_space(IEEE802154_SHORT_ADDR_LEN, 0);
135			*ha = ha_buf;
136		} else {
137			read_unlock_bh(&neigh->lock);
138		}
139		break;
140	case NDISC_NEIGHBOUR_ADVERTISEMENT:
141	case NDISC_NEIGHBOUR_SOLICITATION:
142	case NDISC_ROUTER_SOLICITATION:
143		wpan_dev = lowpan_802154_dev(dev)->wdev->ieee802154_ptr;
144
145		if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr))
146			addr_space = __ndisc_opt_addr_space(IEEE802154_SHORT_ADDR_LEN, 0);
147		break;
148	default:
149		break;
150	}
151
152	return addr_space;
153}
154
155static void lowpan_ndisc_fill_addr_option(const struct net_device *dev,
156					  struct sk_buff *skb, u8 icmp6_type,
157					  const u8 *ha)
158{
159	struct wpan_dev *wpan_dev;
160	__be16 short_addr;
161	u8 opt_type;
162
163	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
164		return;
165
166	switch (icmp6_type) {
167	case NDISC_REDIRECT:
168		if (ha) {
169			ieee802154_le16_to_be16(&short_addr, ha);
170			__ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR,
171						 &short_addr,
172						 IEEE802154_SHORT_ADDR_LEN, 0);
173		}
174		return;
175	case NDISC_NEIGHBOUR_ADVERTISEMENT:
176		opt_type = ND_OPT_TARGET_LL_ADDR;
177		break;
178	case NDISC_ROUTER_SOLICITATION:
179	case NDISC_NEIGHBOUR_SOLICITATION:
180		opt_type = ND_OPT_SOURCE_LL_ADDR;
181		break;
182	default:
183		return;
184	}
185
186	wpan_dev = lowpan_802154_dev(dev)->wdev->ieee802154_ptr;
187
188	if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) {
189		ieee802154_le16_to_be16(&short_addr,
190					&wpan_dev->short_addr);
191		__ndisc_fill_addr_option(skb, opt_type, &short_addr,
192					 IEEE802154_SHORT_ADDR_LEN, 0);
193	}
194}
195
196static void lowpan_ndisc_prefix_rcv_add_addr(struct net *net,
197					     struct net_device *dev,
198					     const struct prefix_info *pinfo,
199					     struct inet6_dev *in6_dev,
200					     struct in6_addr *addr,
201					     int addr_type, u32 addr_flags,
202					     bool sllao, bool tokenized,
203					     __u32 valid_lft,
204					     u32 prefered_lft,
205					     bool dev_addr_generated)
206{
207	int err;
208
209	/* generates short based address for RA PIO's */
210	if (lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154) && dev_addr_generated &&
211	    !addrconf_ifid_802154_6lowpan(addr->s6_addr + 8, dev)) {
212		err = addrconf_prefix_rcv_add_addr(net, dev, pinfo, in6_dev,
213						   addr, addr_type, addr_flags,
214						   sllao, tokenized, valid_lft,
215						   prefered_lft);
216		if (err)
217			ND_PRINTK(2, warn,
218				  "RA: could not add a short address based address for prefix: %pI6c\n",
219				  &pinfo->prefix);
220	}
221}
222#endif
223
224const struct ndisc_ops lowpan_ndisc_ops = {
225	.is_useropt		= lowpan_ndisc_is_useropt,
226#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
227	.parse_options		= lowpan_ndisc_parse_options,
228	.update			= lowpan_ndisc_update,
229	.opt_addr_space		= lowpan_ndisc_opt_addr_space,
230	.fill_addr_option	= lowpan_ndisc_fill_addr_option,
231	.prefix_rcv_add_addr	= lowpan_ndisc_prefix_rcv_add_addr,
232#endif
233};
234