xref: /linux/include/net/lwtunnel.h (revision 3839a7460721b87501134697b7b90c45dcc7825d)
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 enum {
20 	LWTUNNEL_XMIT_DONE,
21 	LWTUNNEL_XMIT_CONTINUE,
22 };
23 
24 
25 struct lwtunnel_state {
26 	__u16		type;
27 	__u16		flags;
28 	__u16		headroom;
29 	atomic_t	refcnt;
30 	int		(*orig_output)(struct net *net, struct sock *sk, struct sk_buff *skb);
31 	int		(*orig_input)(struct sk_buff *);
32 	struct		rcu_head rcu;
33 	__u8            data[];
34 };
35 
36 struct lwtunnel_encap_ops {
37 	int (*build_state)(struct net *net, struct nlattr *encap,
38 			   unsigned int family, const void *cfg,
39 			   struct lwtunnel_state **ts,
40 			   struct netlink_ext_ack *extack);
41 	void (*destroy_state)(struct lwtunnel_state *lws);
42 	int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
43 	int (*input)(struct sk_buff *skb);
44 	int (*fill_encap)(struct sk_buff *skb,
45 			  struct lwtunnel_state *lwtstate);
46 	int (*get_encap_size)(struct lwtunnel_state *lwtstate);
47 	int (*cmp_encap)(struct lwtunnel_state *a, struct lwtunnel_state *b);
48 	int (*xmit)(struct sk_buff *skb);
49 
50 	struct module *owner;
51 };
52 
53 #ifdef CONFIG_LWTUNNEL
54 void lwtstate_free(struct lwtunnel_state *lws);
55 
56 static inline struct lwtunnel_state *
57 lwtstate_get(struct lwtunnel_state *lws)
58 {
59 	if (lws)
60 		atomic_inc(&lws->refcnt);
61 
62 	return lws;
63 }
64 
65 static inline void lwtstate_put(struct lwtunnel_state *lws)
66 {
67 	if (!lws)
68 		return;
69 
70 	if (atomic_dec_and_test(&lws->refcnt))
71 		lwtstate_free(lws);
72 }
73 
74 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
75 {
76 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_OUTPUT_REDIRECT))
77 		return true;
78 
79 	return false;
80 }
81 
82 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
83 {
84 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_INPUT_REDIRECT))
85 		return true;
86 
87 	return false;
88 }
89 
90 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
91 {
92 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_XMIT_REDIRECT))
93 		return true;
94 
95 	return false;
96 }
97 
98 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
99 					     unsigned int mtu)
100 {
101 	if ((lwtunnel_xmit_redirect(lwtstate) ||
102 	     lwtunnel_output_redirect(lwtstate)) && lwtstate->headroom < mtu)
103 		return lwtstate->headroom;
104 
105 	return 0;
106 }
107 
108 int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
109 			   unsigned int num);
110 int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
111 			   unsigned int num);
112 int lwtunnel_valid_encap_type(u16 encap_type,
113 			      struct netlink_ext_ack *extack);
114 int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
115 				   struct netlink_ext_ack *extack);
116 int lwtunnel_build_state(struct net *net, u16 encap_type,
117 			 struct nlattr *encap,
118 			 unsigned int family, const void *cfg,
119 			 struct lwtunnel_state **lws,
120 			 struct netlink_ext_ack *extack);
121 int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate,
122 			int encap_attr, int encap_type_attr);
123 int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
124 struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len);
125 int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b);
126 int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb);
127 int lwtunnel_input(struct sk_buff *skb);
128 int lwtunnel_xmit(struct sk_buff *skb);
129 int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len,
130 			  bool ingress);
131 
132 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
133 {
134 	if (lwtunnel_output_redirect(dst->lwtstate)) {
135 		dst->lwtstate->orig_output = dst->output;
136 		dst->output = lwtunnel_output;
137 	}
138 	if (lwtunnel_input_redirect(dst->lwtstate)) {
139 		dst->lwtstate->orig_input = dst->input;
140 		dst->input = lwtunnel_input;
141 	}
142 }
143 #else
144 
145 static inline void lwtstate_free(struct lwtunnel_state *lws)
146 {
147 }
148 
149 static inline struct lwtunnel_state *
150 lwtstate_get(struct lwtunnel_state *lws)
151 {
152 	return lws;
153 }
154 
155 static inline void lwtstate_put(struct lwtunnel_state *lws)
156 {
157 }
158 
159 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
160 {
161 	return false;
162 }
163 
164 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
165 {
166 	return false;
167 }
168 
169 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
170 {
171 	return false;
172 }
173 
174 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
175 {
176 }
177 
178 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
179 					     unsigned int mtu)
180 {
181 	return 0;
182 }
183 
184 static inline int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
185 					 unsigned int num)
186 {
187 	return -EOPNOTSUPP;
188 
189 }
190 
191 static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
192 					 unsigned int num)
193 {
194 	return -EOPNOTSUPP;
195 }
196 
197 static inline int lwtunnel_valid_encap_type(u16 encap_type,
198 					    struct netlink_ext_ack *extack)
199 {
200 	NL_SET_ERR_MSG(extack, "CONFIG_LWTUNNEL is not enabled in this kernel");
201 	return -EOPNOTSUPP;
202 }
203 static inline int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
204 						 struct netlink_ext_ack *extack)
205 {
206 	/* return 0 since we are not walking attr looking for
207 	 * RTA_ENCAP_TYPE attribute on nexthops.
208 	 */
209 	return 0;
210 }
211 
212 static inline int lwtunnel_build_state(struct net *net, u16 encap_type,
213 				       struct nlattr *encap,
214 				       unsigned int family, const void *cfg,
215 				       struct lwtunnel_state **lws,
216 				       struct netlink_ext_ack *extack)
217 {
218 	return -EOPNOTSUPP;
219 }
220 
221 static inline int lwtunnel_fill_encap(struct sk_buff *skb,
222 				      struct lwtunnel_state *lwtstate,
223 				      int encap_attr, int encap_type_attr)
224 {
225 	return 0;
226 }
227 
228 static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
229 {
230 	return 0;
231 }
232 
233 static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
234 {
235 	return NULL;
236 }
237 
238 static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
239 				     struct lwtunnel_state *b)
240 {
241 	return 0;
242 }
243 
244 static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
245 {
246 	return -EOPNOTSUPP;
247 }
248 
249 static inline int lwtunnel_input(struct sk_buff *skb)
250 {
251 	return -EOPNOTSUPP;
252 }
253 
254 static inline int lwtunnel_xmit(struct sk_buff *skb)
255 {
256 	return -EOPNOTSUPP;
257 }
258 
259 #endif /* CONFIG_LWTUNNEL */
260 
261 #define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
262 
263 #endif /* __NET_LWTUNNEL_H */
264