xref: /openbmc/linux/net/6lowpan/ndisc.c (revision a44e4f3a)
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 
14 static 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
21 static 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 
40 static 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 
56 static 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 
102 static 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 
114 static 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 
155 static 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 
196 static 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 
224 const 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