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 
55 DECLARE_STATIC_KEY_FALSE(nf_hooks_lwtunnel_enabled);
56 
57 void lwtstate_free(struct lwtunnel_state *lws);
58 
59 static inline struct lwtunnel_state *
lwtstate_get(struct lwtunnel_state * lws)60 lwtstate_get(struct lwtunnel_state *lws)
61 {
62 	if (lws)
63 		atomic_inc(&lws->refcnt);
64 
65 	return lws;
66 }
67 
lwtstate_put(struct lwtunnel_state * lws)68 static inline void lwtstate_put(struct lwtunnel_state *lws)
69 {
70 	if (!lws)
71 		return;
72 
73 	if (atomic_dec_and_test(&lws->refcnt))
74 		lwtstate_free(lws);
75 }
76 
lwtunnel_output_redirect(struct lwtunnel_state * lwtstate)77 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
78 {
79 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_OUTPUT_REDIRECT))
80 		return true;
81 
82 	return false;
83 }
84 
lwtunnel_input_redirect(struct lwtunnel_state * lwtstate)85 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
86 {
87 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_INPUT_REDIRECT))
88 		return true;
89 
90 	return false;
91 }
92 
lwtunnel_xmit_redirect(struct lwtunnel_state * lwtstate)93 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
94 {
95 	if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_XMIT_REDIRECT))
96 		return true;
97 
98 	return false;
99 }
100 
lwtunnel_headroom(struct lwtunnel_state * lwtstate,unsigned int mtu)101 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
102 					     unsigned int mtu)
103 {
104 	if ((lwtunnel_xmit_redirect(lwtstate) ||
105 	     lwtunnel_output_redirect(lwtstate)) && lwtstate->headroom < mtu)
106 		return lwtstate->headroom;
107 
108 	return 0;
109 }
110 
111 int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
112 			   unsigned int num);
113 int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
114 			   unsigned int num);
115 int lwtunnel_valid_encap_type(u16 encap_type,
116 			      struct netlink_ext_ack *extack);
117 int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
118 				   struct netlink_ext_ack *extack);
119 int lwtunnel_build_state(struct net *net, u16 encap_type,
120 			 struct nlattr *encap,
121 			 unsigned int family, const void *cfg,
122 			 struct lwtunnel_state **lws,
123 			 struct netlink_ext_ack *extack);
124 int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate,
125 			int encap_attr, int encap_type_attr);
126 int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
127 struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len);
128 int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b);
129 int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb);
130 int lwtunnel_input(struct sk_buff *skb);
131 int lwtunnel_xmit(struct sk_buff *skb);
132 int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len,
133 			  bool ingress);
134 
lwtunnel_set_redirect(struct dst_entry * dst)135 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
136 {
137 	if (lwtunnel_output_redirect(dst->lwtstate)) {
138 		dst->lwtstate->orig_output = dst->output;
139 		dst->output = lwtunnel_output;
140 	}
141 	if (lwtunnel_input_redirect(dst->lwtstate)) {
142 		dst->lwtstate->orig_input = dst->input;
143 		dst->input = lwtunnel_input;
144 	}
145 }
146 #else
147 
lwtstate_free(struct lwtunnel_state * lws)148 static inline void lwtstate_free(struct lwtunnel_state *lws)
149 {
150 }
151 
152 static inline struct lwtunnel_state *
lwtstate_get(struct lwtunnel_state * lws)153 lwtstate_get(struct lwtunnel_state *lws)
154 {
155 	return lws;
156 }
157 
lwtstate_put(struct lwtunnel_state * lws)158 static inline void lwtstate_put(struct lwtunnel_state *lws)
159 {
160 }
161 
lwtunnel_output_redirect(struct lwtunnel_state * lwtstate)162 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
163 {
164 	return false;
165 }
166 
lwtunnel_input_redirect(struct lwtunnel_state * lwtstate)167 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
168 {
169 	return false;
170 }
171 
lwtunnel_xmit_redirect(struct lwtunnel_state * lwtstate)172 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
173 {
174 	return false;
175 }
176 
lwtunnel_set_redirect(struct dst_entry * dst)177 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
178 {
179 }
180 
lwtunnel_headroom(struct lwtunnel_state * lwtstate,unsigned int mtu)181 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
182 					     unsigned int mtu)
183 {
184 	return 0;
185 }
186 
lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops * op,unsigned int num)187 static inline int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
188 					 unsigned int num)
189 {
190 	return -EOPNOTSUPP;
191 
192 }
193 
lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops * op,unsigned int num)194 static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
195 					 unsigned int num)
196 {
197 	return -EOPNOTSUPP;
198 }
199 
lwtunnel_valid_encap_type(u16 encap_type,struct netlink_ext_ack * extack)200 static inline int lwtunnel_valid_encap_type(u16 encap_type,
201 					    struct netlink_ext_ack *extack)
202 {
203 	NL_SET_ERR_MSG(extack, "CONFIG_LWTUNNEL is not enabled in this kernel");
204 	return -EOPNOTSUPP;
205 }
lwtunnel_valid_encap_type_attr(struct nlattr * attr,int len,struct netlink_ext_ack * extack)206 static inline int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
207 						 struct netlink_ext_ack *extack)
208 {
209 	/* return 0 since we are not walking attr looking for
210 	 * RTA_ENCAP_TYPE attribute on nexthops.
211 	 */
212 	return 0;
213 }
214 
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)215 static inline int lwtunnel_build_state(struct net *net, u16 encap_type,
216 				       struct nlattr *encap,
217 				       unsigned int family, const void *cfg,
218 				       struct lwtunnel_state **lws,
219 				       struct netlink_ext_ack *extack)
220 {
221 	return -EOPNOTSUPP;
222 }
223 
lwtunnel_fill_encap(struct sk_buff * skb,struct lwtunnel_state * lwtstate,int encap_attr,int encap_type_attr)224 static inline int lwtunnel_fill_encap(struct sk_buff *skb,
225 				      struct lwtunnel_state *lwtstate,
226 				      int encap_attr, int encap_type_attr)
227 {
228 	return 0;
229 }
230 
lwtunnel_get_encap_size(struct lwtunnel_state * lwtstate)231 static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
232 {
233 	return 0;
234 }
235 
lwtunnel_state_alloc(int hdr_len)236 static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
237 {
238 	return NULL;
239 }
240 
lwtunnel_cmp_encap(struct lwtunnel_state * a,struct lwtunnel_state * b)241 static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
242 				     struct lwtunnel_state *b)
243 {
244 	return 0;
245 }
246 
lwtunnel_output(struct net * net,struct sock * sk,struct sk_buff * skb)247 static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
248 {
249 	return -EOPNOTSUPP;
250 }
251 
lwtunnel_input(struct sk_buff * skb)252 static inline int lwtunnel_input(struct sk_buff *skb)
253 {
254 	return -EOPNOTSUPP;
255 }
256 
lwtunnel_xmit(struct sk_buff * skb)257 static inline int lwtunnel_xmit(struct sk_buff *skb)
258 {
259 	return -EOPNOTSUPP;
260 }
261 
262 #endif /* CONFIG_LWTUNNEL */
263 
264 #define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
265 
266 #endif /* __NET_LWTUNNEL_H */
267