xref: /linux/net/ipv6/addrconf_core.c (revision b8d312aa075f33282565467662c4628dae0a2aff)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * IPv6 library code, needed by static components when full IPv6 support is
4  * not configured or static.
5  */
6 
7 #include <linux/export.h>
8 #include <net/ipv6.h>
9 #include <net/ipv6_stubs.h>
10 #include <net/ip.h>
11 
12 /* if ipv6 module registers this function is used by xfrm to force all
13  * sockets to relookup their nodes - this is fairly expensive, be
14  * careful
15  */
16 void (*__fib6_flush_trees)(struct net *);
17 EXPORT_SYMBOL(__fib6_flush_trees);
18 
19 #define IPV6_ADDR_SCOPE_TYPE(scope)	((scope) << 16)
20 
21 static inline unsigned int ipv6_addr_scope2type(unsigned int scope)
22 {
23 	switch (scope) {
24 	case IPV6_ADDR_SCOPE_NODELOCAL:
25 		return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_NODELOCAL) |
26 			IPV6_ADDR_LOOPBACK);
27 	case IPV6_ADDR_SCOPE_LINKLOCAL:
28 		return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL) |
29 			IPV6_ADDR_LINKLOCAL);
30 	case IPV6_ADDR_SCOPE_SITELOCAL:
31 		return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_SITELOCAL) |
32 			IPV6_ADDR_SITELOCAL);
33 	}
34 	return IPV6_ADDR_SCOPE_TYPE(scope);
35 }
36 
37 int __ipv6_addr_type(const struct in6_addr *addr)
38 {
39 	__be32 st;
40 
41 	st = addr->s6_addr32[0];
42 
43 	/* Consider all addresses with the first three bits different of
44 	   000 and 111 as unicasts.
45 	 */
46 	if ((st & htonl(0xE0000000)) != htonl(0x00000000) &&
47 	    (st & htonl(0xE0000000)) != htonl(0xE0000000))
48 		return (IPV6_ADDR_UNICAST |
49 			IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));
50 
51 	if ((st & htonl(0xFF000000)) == htonl(0xFF000000)) {
52 		/* multicast */
53 		/* addr-select 3.1 */
54 		return (IPV6_ADDR_MULTICAST |
55 			ipv6_addr_scope2type(IPV6_ADDR_MC_SCOPE(addr)));
56 	}
57 
58 	if ((st & htonl(0xFFC00000)) == htonl(0xFE800000))
59 		return (IPV6_ADDR_LINKLOCAL | IPV6_ADDR_UNICAST |
60 			IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL));		/* addr-select 3.1 */
61 	if ((st & htonl(0xFFC00000)) == htonl(0xFEC00000))
62 		return (IPV6_ADDR_SITELOCAL | IPV6_ADDR_UNICAST |
63 			IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_SITELOCAL));		/* addr-select 3.1 */
64 	if ((st & htonl(0xFE000000)) == htonl(0xFC000000))
65 		return (IPV6_ADDR_UNICAST |
66 			IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));			/* RFC 4193 */
67 
68 	if ((addr->s6_addr32[0] | addr->s6_addr32[1]) == 0) {
69 		if (addr->s6_addr32[2] == 0) {
70 			if (addr->s6_addr32[3] == 0)
71 				return IPV6_ADDR_ANY;
72 
73 			if (addr->s6_addr32[3] == htonl(0x00000001))
74 				return (IPV6_ADDR_LOOPBACK | IPV6_ADDR_UNICAST |
75 					IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL));	/* addr-select 3.4 */
76 
77 			return (IPV6_ADDR_COMPATv4 | IPV6_ADDR_UNICAST |
78 				IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));	/* addr-select 3.3 */
79 		}
80 
81 		if (addr->s6_addr32[2] == htonl(0x0000ffff))
82 			return (IPV6_ADDR_MAPPED |
83 				IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));	/* addr-select 3.3 */
84 	}
85 
86 	return (IPV6_ADDR_UNICAST |
87 		IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));	/* addr-select 3.4 */
88 }
89 EXPORT_SYMBOL(__ipv6_addr_type);
90 
91 static ATOMIC_NOTIFIER_HEAD(inet6addr_chain);
92 static BLOCKING_NOTIFIER_HEAD(inet6addr_validator_chain);
93 
94 int register_inet6addr_notifier(struct notifier_block *nb)
95 {
96 	return atomic_notifier_chain_register(&inet6addr_chain, nb);
97 }
98 EXPORT_SYMBOL(register_inet6addr_notifier);
99 
100 int unregister_inet6addr_notifier(struct notifier_block *nb)
101 {
102 	return atomic_notifier_chain_unregister(&inet6addr_chain, nb);
103 }
104 EXPORT_SYMBOL(unregister_inet6addr_notifier);
105 
106 int inet6addr_notifier_call_chain(unsigned long val, void *v)
107 {
108 	return atomic_notifier_call_chain(&inet6addr_chain, val, v);
109 }
110 EXPORT_SYMBOL(inet6addr_notifier_call_chain);
111 
112 int register_inet6addr_validator_notifier(struct notifier_block *nb)
113 {
114 	return blocking_notifier_chain_register(&inet6addr_validator_chain, nb);
115 }
116 EXPORT_SYMBOL(register_inet6addr_validator_notifier);
117 
118 int unregister_inet6addr_validator_notifier(struct notifier_block *nb)
119 {
120 	return blocking_notifier_chain_unregister(&inet6addr_validator_chain,
121 						  nb);
122 }
123 EXPORT_SYMBOL(unregister_inet6addr_validator_notifier);
124 
125 int inet6addr_validator_notifier_call_chain(unsigned long val, void *v)
126 {
127 	return blocking_notifier_call_chain(&inet6addr_validator_chain, val, v);
128 }
129 EXPORT_SYMBOL(inet6addr_validator_notifier_call_chain);
130 
131 static int eafnosupport_ipv6_dst_lookup(struct net *net, struct sock *u1,
132 					struct dst_entry **u2,
133 					struct flowi6 *u3)
134 {
135 	return -EAFNOSUPPORT;
136 }
137 
138 static int eafnosupport_ipv6_route_input(struct sk_buff *skb)
139 {
140 	return -EAFNOSUPPORT;
141 }
142 
143 static struct fib6_table *eafnosupport_fib6_get_table(struct net *net, u32 id)
144 {
145 	return NULL;
146 }
147 
148 static int
149 eafnosupport_fib6_table_lookup(struct net *net, struct fib6_table *table,
150 			       int oif, struct flowi6 *fl6,
151 			       struct fib6_result *res, int flags)
152 {
153 	return -EAFNOSUPPORT;
154 }
155 
156 static int
157 eafnosupport_fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
158 			 struct fib6_result *res, int flags)
159 {
160 	return -EAFNOSUPPORT;
161 }
162 
163 static void
164 eafnosupport_fib6_select_path(const struct net *net, struct fib6_result *res,
165 			      struct flowi6 *fl6, int oif, bool have_oif_match,
166 			      const struct sk_buff *skb, int strict)
167 {
168 }
169 
170 static u32
171 eafnosupport_ip6_mtu_from_fib6(const struct fib6_result *res,
172 			       const struct in6_addr *daddr,
173 			       const struct in6_addr *saddr)
174 {
175 	return 0;
176 }
177 
178 static int eafnosupport_fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
179 				     struct fib6_config *cfg, gfp_t gfp_flags,
180 				     struct netlink_ext_ack *extack)
181 {
182 	NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
183 	return -EAFNOSUPPORT;
184 }
185 
186 static int eafnosupport_ip6_del_rt(struct net *net, struct fib6_info *rt)
187 {
188 	return -EAFNOSUPPORT;
189 }
190 
191 const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
192 	.ipv6_dst_lookup   = eafnosupport_ipv6_dst_lookup,
193 	.ipv6_route_input  = eafnosupport_ipv6_route_input,
194 	.fib6_get_table    = eafnosupport_fib6_get_table,
195 	.fib6_table_lookup = eafnosupport_fib6_table_lookup,
196 	.fib6_lookup       = eafnosupport_fib6_lookup,
197 	.fib6_select_path  = eafnosupport_fib6_select_path,
198 	.ip6_mtu_from_fib6 = eafnosupport_ip6_mtu_from_fib6,
199 	.fib6_nh_init	   = eafnosupport_fib6_nh_init,
200 	.ip6_del_rt	   = eafnosupport_ip6_del_rt,
201 };
202 EXPORT_SYMBOL_GPL(ipv6_stub);
203 
204 /* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
205 const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;
206 EXPORT_SYMBOL(in6addr_loopback);
207 const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
208 EXPORT_SYMBOL(in6addr_any);
209 const struct in6_addr in6addr_linklocal_allnodes = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
210 EXPORT_SYMBOL(in6addr_linklocal_allnodes);
211 const struct in6_addr in6addr_linklocal_allrouters = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
212 EXPORT_SYMBOL(in6addr_linklocal_allrouters);
213 const struct in6_addr in6addr_interfacelocal_allnodes = IN6ADDR_INTERFACELOCAL_ALLNODES_INIT;
214 EXPORT_SYMBOL(in6addr_interfacelocal_allnodes);
215 const struct in6_addr in6addr_interfacelocal_allrouters = IN6ADDR_INTERFACELOCAL_ALLROUTERS_INIT;
216 EXPORT_SYMBOL(in6addr_interfacelocal_allrouters);
217 const struct in6_addr in6addr_sitelocal_allrouters = IN6ADDR_SITELOCAL_ALLROUTERS_INIT;
218 EXPORT_SYMBOL(in6addr_sitelocal_allrouters);
219 
220 static void snmp6_free_dev(struct inet6_dev *idev)
221 {
222 	kfree(idev->stats.icmpv6msgdev);
223 	kfree(idev->stats.icmpv6dev);
224 	free_percpu(idev->stats.ipv6);
225 }
226 
227 static void in6_dev_finish_destroy_rcu(struct rcu_head *head)
228 {
229 	struct inet6_dev *idev = container_of(head, struct inet6_dev, rcu);
230 
231 	snmp6_free_dev(idev);
232 	kfree(idev);
233 }
234 
235 /* Nobody refers to this device, we may destroy it. */
236 
237 void in6_dev_finish_destroy(struct inet6_dev *idev)
238 {
239 	struct net_device *dev = idev->dev;
240 
241 	WARN_ON(!list_empty(&idev->addr_list));
242 	WARN_ON(idev->mc_list);
243 	WARN_ON(timer_pending(&idev->rs_timer));
244 
245 #ifdef NET_REFCNT_DEBUG
246 	pr_debug("%s: %s\n", __func__, dev ? dev->name : "NIL");
247 #endif
248 	dev_put(dev);
249 	if (!idev->dead) {
250 		pr_warn("Freeing alive inet6 device %p\n", idev);
251 		return;
252 	}
253 	call_rcu(&idev->rcu, in6_dev_finish_destroy_rcu);
254 }
255 EXPORT_SYMBOL(in6_dev_finish_destroy);
256