xref: /linux/include/net/lwtunnel.h (revision a1c613ae4c322ddd58d5a8539dbfba2a0380a8c0)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_LWTUNNEL_H
3 #define __NET_LWTUNNEL_H 1
4 
5 #include <linux/lwtunnel.h>
6 #include <linux/netdevice.h>
7 #include <linux/skbuff.h>
8 #include <linux/types.h>
9 #include <net/route.h>
10 
11 #define LWTUNNEL_HASH_BITS   7
12 #define LWTUNNEL_HASH_SIZE   (1 << LWTUNNEL_HASH_BITS)
13 
14 /* lw tunnel state flags */
15 #define LWTUNNEL_STATE_OUTPUT_REDIRECT	BIT(0)
16 #define LWTUNNEL_STATE_INPUT_REDIRECT	BIT(1)
17 #define LWTUNNEL_STATE_XMIT_REDIRECT	BIT(2)
18 
19 /* LWTUNNEL_XMIT_CONTINUE should be distinguishable from dst_output return
20  * values (NET_XMIT_xxx and NETDEV_TX_xxx in linux/netdevice.h) for safety.
21  */
22 enum {
23 	LWTUNNEL_XMIT_DONE,
24 	LWTUNNEL_XMIT_CONTINUE = 0x100,
25 };
26 
27 
28 struct lwtunnel_state {
29 	__u16		type;
30 	__u16		flags;
31 	__u16		headroom;
32 	atomic_t	refcnt;
33 	int		(*orig_output)(struct net *net, struct sock *sk, struct sk_buff *skb);
34 	int		(*orig_input)(struct sk_buff *);
35 	struct		rcu_head rcu;
36 	__u8            data[];
37 };
38 
39 struct lwtunnel_encap_ops {
40 	int (*build_state)(struct net *net, struct nlattr *encap,
41 			   unsigned int family, const void *cfg,
42 			   struct lwtunnel_state **ts,
43 			   struct netlink_ext_ack *extack);
44 	void (*destroy_state)(struct lwtunnel_state *lws);
45 	int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
46 	int (*input)(struct sk_buff *skb);
47 	int (*fill_encap)(struct sk_buff *skb,
48 			  struct lwtunnel_state *lwtstate);
49 	int (*get_encap_size)(struct lwtunnel_state *lwtstate);
50 	int (*cmp_encap)(struct lwtunnel_state *a, struct lwtunnel_state *b);
51 	int (*xmit)(struct sk_buff *skb);
52 
53 	struct module *owner;
54 };
55 
56 #ifdef CONFIG_LWTUNNEL
57 
58 DECLARE_STATIC_KEY_FALSE(nf_hooks_lwtunnel_enabled);
59 
60 void lwtstate_free(struct lwtunnel_state *lws);
61 
62 static inline struct lwtunnel_state *
lwtstate_get(struct lwtunnel_state * lws)63 lwtstate_get(struct lwtunnel_state *lws)
64 {
65 	if (lws)
66 		atomic_inc(&lws->refcnt);
67 
68 	return lws;
69 }
70 
lwtstate_put(struct lwtunnel_state * lws)71 static inline void lwtstate_put(struct lwtunnel_state *lws)
72 {
73 	if (!lws)
74 		return;
75 
76 	if (atomic_dec_and_test(&lws->refcnt))
77 		lwtstate_free(lws);
78 }
79 
lwtunnel_output_redirect(struct lwtunnel_state * lwtstate)80 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
81 {
82 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_OUTPUT_REDIRECT))
83 		return true;
84 
85 	return false;
86 }
87 
lwtunnel_input_redirect(struct lwtunnel_state * lwtstate)88 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
89 {
90 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_INPUT_REDIRECT))
91 		return true;
92 
93 	return false;
94 }
95 
lwtunnel_xmit_redirect(struct lwtunnel_state * lwtstate)96 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
97 {
98 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_XMIT_REDIRECT))
99 		return true;
100 
101 	return false;
102 }
103 
lwtunnel_headroom(struct lwtunnel_state * lwtstate,unsigned int mtu)104 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
105 					     unsigned int mtu)
106 {
107 	if ((lwtunnel_xmit_redirect(lwtstate) ||
108 	     lwtunnel_output_redirect(lwtstate)) && lwtstate->headroom < mtu)
109 		return lwtstate->headroom;
110 
111 	return 0;
112 }
113 
114 int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
115 			   unsigned int num);
116 int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
117 			   unsigned int num);
118 int lwtunnel_valid_encap_type(u16 encap_type,
119 			      struct netlink_ext_ack *extack);
120 int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
121 				   struct netlink_ext_ack *extack);
122 int lwtunnel_build_state(struct net *net, u16 encap_type,
123 			 struct nlattr *encap,
124 			 unsigned int family, const void *cfg,
125 			 struct lwtunnel_state **lws,
126 			 struct netlink_ext_ack *extack);
127 int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate,
128 			int encap_attr, int encap_type_attr);
129 int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
130 struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len);
131 int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b);
132 int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb);
133 int lwtunnel_input(struct sk_buff *skb);
134 int lwtunnel_xmit(struct sk_buff *skb);
135 int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len,
136 			  bool ingress);
137 
lwtunnel_set_redirect(struct dst_entry * dst)138 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
139 {
140 	if (lwtunnel_output_redirect(dst->lwtstate)) {
141 		dst->lwtstate->orig_output = dst->output;
142 		dst->output = lwtunnel_output;
143 	}
144 	if (lwtunnel_input_redirect(dst->lwtstate)) {
145 		dst->lwtstate->orig_input = dst->input;
146 		dst->input = lwtunnel_input;
147 	}
148 }
149 #else
150 
lwtstate_free(struct lwtunnel_state * lws)151 static inline void lwtstate_free(struct lwtunnel_state *lws)
152 {
153 }
154 
155 static inline struct lwtunnel_state *
lwtstate_get(struct lwtunnel_state * lws)156 lwtstate_get(struct lwtunnel_state *lws)
157 {
158 	return lws;
159 }
160 
lwtstate_put(struct lwtunnel_state * lws)161 static inline void lwtstate_put(struct lwtunnel_state *lws)
162 {
163 }
164 
lwtunnel_output_redirect(struct lwtunnel_state * lwtstate)165 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
166 {
167 	return false;
168 }
169 
lwtunnel_input_redirect(struct lwtunnel_state * lwtstate)170 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
171 {
172 	return false;
173 }
174 
lwtunnel_xmit_redirect(struct lwtunnel_state * lwtstate)175 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
176 {
177 	return false;
178 }
179 
lwtunnel_set_redirect(struct dst_entry * dst)180 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
181 {
182 }
183 
lwtunnel_headroom(struct lwtunnel_state * lwtstate,unsigned int mtu)184 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
185 					     unsigned int mtu)
186 {
187 	return 0;
188 }
189 
lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops * op,unsigned int num)190 static inline int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
191 					 unsigned int num)
192 {
193 	return -EOPNOTSUPP;
194 
195 }
196 
lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops * op,unsigned int num)197 static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
198 					 unsigned int num)
199 {
200 	return -EOPNOTSUPP;
201 }
202 
lwtunnel_valid_encap_type(u16 encap_type,struct netlink_ext_ack * extack)203 static inline int lwtunnel_valid_encap_type(u16 encap_type,
204 					    struct netlink_ext_ack *extack)
205 {
206 	NL_SET_ERR_MSG(extack, "CONFIG_LWTUNNEL is not enabled in this kernel");
207 	return -EOPNOTSUPP;
208 }
lwtunnel_valid_encap_type_attr(struct nlattr * attr,int len,struct netlink_ext_ack * extack)209 static inline int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
210 						 struct netlink_ext_ack *extack)
211 {
212 	/* return 0 since we are not walking attr looking for
213 	 * RTA_ENCAP_TYPE attribute on nexthops.
214 	 */
215 	return 0;
216 }
217 
lwtunnel_build_state(struct net * net,u16 encap_type,struct nlattr * encap,unsigned int family,const void * cfg,struct lwtunnel_state ** lws,struct netlink_ext_ack * extack)218 static inline int lwtunnel_build_state(struct net *net, u16 encap_type,
219 				       struct nlattr *encap,
220 				       unsigned int family, const void *cfg,
221 				       struct lwtunnel_state **lws,
222 				       struct netlink_ext_ack *extack)
223 {
224 	return -EOPNOTSUPP;
225 }
226 
lwtunnel_fill_encap(struct sk_buff * skb,struct lwtunnel_state * lwtstate,int encap_attr,int encap_type_attr)227 static inline int lwtunnel_fill_encap(struct sk_buff *skb,
228 				      struct lwtunnel_state *lwtstate,
229 				      int encap_attr, int encap_type_attr)
230 {
231 	return 0;
232 }
233 
lwtunnel_get_encap_size(struct lwtunnel_state * lwtstate)234 static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
235 {
236 	return 0;
237 }
238 
lwtunnel_state_alloc(int hdr_len)239 static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
240 {
241 	return NULL;
242 }
243 
lwtunnel_cmp_encap(struct lwtunnel_state * a,struct lwtunnel_state * b)244 static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
245 				     struct lwtunnel_state *b)
246 {
247 	return 0;
248 }
249 
lwtunnel_output(struct net * net,struct sock * sk,struct sk_buff * skb)250 static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
251 {
252 	return -EOPNOTSUPP;
253 }
254 
lwtunnel_input(struct sk_buff * skb)255 static inline int lwtunnel_input(struct sk_buff *skb)
256 {
257 	return -EOPNOTSUPP;
258 }
259 
lwtunnel_xmit(struct sk_buff * skb)260 static inline int lwtunnel_xmit(struct sk_buff *skb)
261 {
262 	return -EOPNOTSUPP;
263 }
264 
265 #endif /* CONFIG_LWTUNNEL */
266 
267 #define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
268 
269 #endif /* __NET_LWTUNNEL_H */
270