1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _NET_IP6_ROUTE_H
3#define _NET_IP6_ROUTE_H
4
5#include <net/addrconf.h>
6#include <net/flow.h>
7#include <net/ip6_fib.h>
8#include <net/sock.h>
9#include <net/lwtunnel.h>
10#include <linux/ip.h>
11#include <linux/ipv6.h>
12#include <linux/route.h>
13#include <net/nexthop.h>
14
15struct route_info {
16	__u8			type;
17	__u8			length;
18	__u8			prefix_len;
19#if defined(__BIG_ENDIAN_BITFIELD)
20	__u8			reserved_h:3,
21				route_pref:2,
22				reserved_l:3;
23#elif defined(__LITTLE_ENDIAN_BITFIELD)
24	__u8			reserved_l:3,
25				route_pref:2,
26				reserved_h:3;
27#endif
28	__be32			lifetime;
29	__u8			prefix[];	/* 0,8 or 16 */
30};
31
32#define RT6_LOOKUP_F_IFACE		0x00000001
33#define RT6_LOOKUP_F_REACHABLE		0x00000002
34#define RT6_LOOKUP_F_HAS_SADDR		0x00000004
35#define RT6_LOOKUP_F_SRCPREF_TMP	0x00000008
36#define RT6_LOOKUP_F_SRCPREF_PUBLIC	0x00000010
37#define RT6_LOOKUP_F_SRCPREF_COA	0x00000020
38#define RT6_LOOKUP_F_IGNORE_LINKSTATE	0x00000040
39#define RT6_LOOKUP_F_DST_NOREF		0x00000080
40
41/* We do not (yet ?) support IPv6 jumbograms (RFC 2675)
42 * Unlike IPv4, hdr->seg_len doesn't include the IPv6 header
43 */
44#define IP6_MAX_MTU (0xFFFF + sizeof(struct ipv6hdr))
45
46/*
47 * rt6_srcprefs2flags() and rt6_flags2srcprefs() translate
48 * between IPV6_ADDR_PREFERENCES socket option values
49 *	IPV6_PREFER_SRC_TMP    = 0x1
50 *	IPV6_PREFER_SRC_PUBLIC = 0x2
51 *	IPV6_PREFER_SRC_COA    = 0x4
52 * and above RT6_LOOKUP_F_SRCPREF_xxx flags.
53 */
54static inline int rt6_srcprefs2flags(unsigned int srcprefs)
55{
56	return (srcprefs & IPV6_PREFER_SRC_MASK) << 3;
57}
58
59static inline unsigned int rt6_flags2srcprefs(int flags)
60{
61	return (flags >> 3) & IPV6_PREFER_SRC_MASK;
62}
63
64static inline bool rt6_need_strict(const struct in6_addr *daddr)
65{
66	return ipv6_addr_type(daddr) &
67		(IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);
68}
69
70/* fib entries using a nexthop object can not be coalesced into
71 * a multipath route
72 */
73static inline bool rt6_qualify_for_ecmp(const struct fib6_info *f6i)
74{
75	/* the RTF_ADDRCONF flag filters out RA's */
76	return !(f6i->fib6_flags & RTF_ADDRCONF) && !f6i->nh &&
77		f6i->fib6_nh->fib_nh_gw_family;
78}
79
80void ip6_route_input(struct sk_buff *skb);
81struct dst_entry *ip6_route_input_lookup(struct net *net,
82					 struct net_device *dev,
83					 struct flowi6 *fl6,
84					 const struct sk_buff *skb, int flags);
85
86struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk,
87					 struct flowi6 *fl6, int flags);
88
89static inline struct dst_entry *ip6_route_output(struct net *net,
90						 const struct sock *sk,
91						 struct flowi6 *fl6)
92{
93	return ip6_route_output_flags(net, sk, fl6, 0);
94}
95
96/* Only conditionally release dst if flags indicates
97 * !RT6_LOOKUP_F_DST_NOREF or dst is in uncached_list.
98 */
99static inline void ip6_rt_put_flags(struct rt6_info *rt, int flags)
100{
101	if (!(flags & RT6_LOOKUP_F_DST_NOREF) ||
102	    !list_empty(&rt->dst.rt_uncached))
103		ip6_rt_put(rt);
104}
105
106struct dst_entry *ip6_route_lookup(struct net *net, struct flowi6 *fl6,
107				   const struct sk_buff *skb, int flags);
108struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
109			       int ifindex, struct flowi6 *fl6,
110			       const struct sk_buff *skb, int flags);
111
112void ip6_route_init_special_entries(void);
113int ip6_route_init(void);
114void ip6_route_cleanup(void);
115
116int ipv6_route_ioctl(struct net *net, unsigned int cmd,
117		struct in6_rtmsg *rtmsg);
118
119int ip6_route_add(struct fib6_config *cfg, gfp_t gfp_flags,
120		  struct netlink_ext_ack *extack);
121int ip6_ins_rt(struct net *net, struct fib6_info *f6i);
122int ip6_del_rt(struct net *net, struct fib6_info *f6i, bool skip_notify);
123
124void rt6_flush_exceptions(struct fib6_info *f6i);
125void rt6_age_exceptions(struct fib6_info *f6i, struct fib6_gc_args *gc_args,
126			unsigned long now);
127
128static inline int ip6_route_get_saddr(struct net *net, struct fib6_info *f6i,
129				      const struct in6_addr *daddr,
130				      unsigned int prefs,
131				      struct in6_addr *saddr)
132{
133	int err = 0;
134
135	if (f6i && f6i->fib6_prefsrc.plen) {
136		*saddr = f6i->fib6_prefsrc.addr;
137	} else {
138		struct net_device *dev = f6i ? fib6_info_nh_dev(f6i) : NULL;
139
140		err = ipv6_dev_get_saddr(net, dev, daddr, prefs, saddr);
141	}
142
143	return err;
144}
145
146struct rt6_info *rt6_lookup(struct net *net, const struct in6_addr *daddr,
147			    const struct in6_addr *saddr, int oif,
148			    const struct sk_buff *skb, int flags);
149u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
150		       const struct sk_buff *skb, struct flow_keys *hkeys);
151
152struct dst_entry *icmp6_dst_alloc(struct net_device *dev, struct flowi6 *fl6);
153
154void fib6_force_start_gc(struct net *net);
155
156struct fib6_info *addrconf_f6i_alloc(struct net *net, struct inet6_dev *idev,
157				     const struct in6_addr *addr, bool anycast,
158				     gfp_t gfp_flags, struct netlink_ext_ack *extack);
159
160struct rt6_info *ip6_dst_alloc(struct net *net, struct net_device *dev,
161			       int flags);
162
163/*
164 *	support functions for ND
165 *
166 */
167struct fib6_info *rt6_get_dflt_router(struct net *net,
168				     const struct in6_addr *addr,
169				     struct net_device *dev);
170struct fib6_info *rt6_add_dflt_router(struct net *net,
171				     const struct in6_addr *gwaddr,
172				     struct net_device *dev, unsigned int pref,
173				     u32 defrtr_usr_metric,
174				     int lifetime);
175
176void rt6_purge_dflt_routers(struct net *net);
177
178int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
179		  const struct in6_addr *gwaddr);
180
181void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu, int oif,
182		     u32 mark, kuid_t uid);
183void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, __be32 mtu);
184void ip6_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
185		  kuid_t uid);
186void ip6_redirect_no_header(struct sk_buff *skb, struct net *net, int oif);
187void ip6_sk_redirect(struct sk_buff *skb, struct sock *sk);
188
189struct netlink_callback;
190
191struct rt6_rtnl_dump_arg {
192	struct sk_buff *skb;
193	struct netlink_callback *cb;
194	struct net *net;
195	struct fib_dump_filter filter;
196};
197
198int rt6_dump_route(struct fib6_info *f6i, void *p_arg, unsigned int skip);
199void rt6_mtu_change(struct net_device *dev, unsigned int mtu);
200void rt6_remove_prefsrc(struct inet6_ifaddr *ifp);
201void rt6_clean_tohost(struct net *net, struct in6_addr *gateway);
202void rt6_sync_up(struct net_device *dev, unsigned char nh_flags);
203void rt6_disable_ip(struct net_device *dev, unsigned long event);
204void rt6_sync_down_dev(struct net_device *dev, unsigned long event);
205void rt6_multipath_rebalance(struct fib6_info *f6i);
206
207void rt6_uncached_list_add(struct rt6_info *rt);
208void rt6_uncached_list_del(struct rt6_info *rt);
209
210static inline const struct rt6_info *skb_rt6_info(const struct sk_buff *skb)
211{
212	const struct dst_entry *dst = skb_dst(skb);
213	const struct rt6_info *rt6 = NULL;
214
215	if (dst)
216		rt6 = container_of(dst, struct rt6_info, dst);
217
218	return rt6;
219}
220
221/*
222 *	Store a destination cache entry in a socket
223 */
224static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
225				 const struct in6_addr *daddr,
226				 const struct in6_addr *saddr)
227{
228	struct ipv6_pinfo *np = inet6_sk(sk);
229
230	np->dst_cookie = rt6_get_cookie((struct rt6_info *)dst);
231	sk_setup_caps(sk, dst);
232	np->daddr_cache = daddr;
233#ifdef CONFIG_IPV6_SUBTREES
234	np->saddr_cache = saddr;
235#endif
236}
237
238void ip6_sk_dst_store_flow(struct sock *sk, struct dst_entry *dst,
239			   const struct flowi6 *fl6);
240
241static inline bool ipv6_unicast_destination(const struct sk_buff *skb)
242{
243	struct rt6_info *rt = (struct rt6_info *) skb_dst(skb);
244
245	return rt->rt6i_flags & RTF_LOCAL;
246}
247
248static inline bool ipv6_anycast_destination(const struct dst_entry *dst,
249					    const struct in6_addr *daddr)
250{
251	struct rt6_info *rt = (struct rt6_info *)dst;
252
253	return rt->rt6i_flags & RTF_ANYCAST ||
254		(rt->rt6i_dst.plen < 127 &&
255		 !(rt->rt6i_flags & (RTF_GATEWAY | RTF_NONEXTHOP)) &&
256		 ipv6_addr_equal(&rt->rt6i_dst.addr, daddr));
257}
258
259int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
260		 int (*output)(struct net *, struct sock *, struct sk_buff *));
261
262static inline unsigned int ip6_skb_dst_mtu(const struct sk_buff *skb)
263{
264	const struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
265				inet6_sk(skb->sk) : NULL;
266	const struct dst_entry *dst = skb_dst(skb);
267	unsigned int mtu;
268
269	if (np && READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE) {
270		mtu = READ_ONCE(dst->dev->mtu);
271		mtu -= lwtunnel_headroom(dst->lwtstate, mtu);
272	} else {
273		mtu = dst_mtu(dst);
274	}
275	return mtu;
276}
277
278static inline bool ip6_sk_accept_pmtu(const struct sock *sk)
279{
280	u8 pmtudisc = READ_ONCE(inet6_sk(sk)->pmtudisc);
281
282	return pmtudisc != IPV6_PMTUDISC_INTERFACE &&
283	       pmtudisc != IPV6_PMTUDISC_OMIT;
284}
285
286static inline bool ip6_sk_ignore_df(const struct sock *sk)
287{
288	u8 pmtudisc = READ_ONCE(inet6_sk(sk)->pmtudisc);
289
290	return pmtudisc < IPV6_PMTUDISC_DO ||
291	       pmtudisc == IPV6_PMTUDISC_OMIT;
292}
293
294static inline const struct in6_addr *rt6_nexthop(const struct rt6_info *rt,
295						 const struct in6_addr *daddr)
296{
297	if (rt->rt6i_flags & RTF_GATEWAY)
298		return &rt->rt6i_gateway;
299	else if (unlikely(rt->rt6i_flags & RTF_CACHE))
300		return &rt->rt6i_dst.addr;
301	else
302		return daddr;
303}
304
305static inline bool rt6_duplicate_nexthop(struct fib6_info *a, struct fib6_info *b)
306{
307	struct fib6_nh *nha, *nhb;
308
309	if (a->nh || b->nh)
310		return nexthop_cmp(a->nh, b->nh);
311
312	nha = a->fib6_nh;
313	nhb = b->fib6_nh;
314	return nha->fib_nh_dev == nhb->fib_nh_dev &&
315	       ipv6_addr_equal(&nha->fib_nh_gw6, &nhb->fib_nh_gw6) &&
316	       !lwtunnel_cmp_encap(nha->fib_nh_lws, nhb->fib_nh_lws);
317}
318
319static inline unsigned int ip6_dst_mtu_maybe_forward(const struct dst_entry *dst,
320						     bool forwarding)
321{
322	struct inet6_dev *idev;
323	unsigned int mtu;
324
325	if (!forwarding || dst_metric_locked(dst, RTAX_MTU)) {
326		mtu = dst_metric_raw(dst, RTAX_MTU);
327		if (mtu)
328			goto out;
329	}
330
331	mtu = IPV6_MIN_MTU;
332	rcu_read_lock();
333	idev = __in6_dev_get(dst->dev);
334	if (idev)
335		mtu = READ_ONCE(idev->cnf.mtu6);
336	rcu_read_unlock();
337
338out:
339	return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
340}
341
342u32 ip6_mtu_from_fib6(const struct fib6_result *res,
343		      const struct in6_addr *daddr,
344		      const struct in6_addr *saddr);
345
346struct neighbour *ip6_neigh_lookup(const struct in6_addr *gw,
347				   struct net_device *dev, struct sk_buff *skb,
348				   const void *daddr);
349#endif
350