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 = READ_ONCE(dst->output);
142 WRITE_ONCE(dst->output, lwtunnel_output);
143 }
144 if (lwtunnel_input_redirect(dst->lwtstate)) {
145 dst->lwtstate->orig_input = READ_ONCE(dst->input);
146 WRITE_ONCE(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 }
209
lwtunnel_valid_encap_type_attr(struct nlattr * attr,int len,struct netlink_ext_ack * extack)210 static inline int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
211 struct netlink_ext_ack *extack)
212 {
213 /* return 0 since we are not walking attr looking for
214 * RTA_ENCAP_TYPE attribute on nexthops.
215 */
216 return 0;
217 }
218
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)219 static inline int lwtunnel_build_state(struct net *net, u16 encap_type,
220 struct nlattr *encap,
221 unsigned int family, const void *cfg,
222 struct lwtunnel_state **lws,
223 struct netlink_ext_ack *extack)
224 {
225 return -EOPNOTSUPP;
226 }
227
lwtunnel_fill_encap(struct sk_buff * skb,struct lwtunnel_state * lwtstate,int encap_attr,int encap_type_attr)228 static inline int lwtunnel_fill_encap(struct sk_buff *skb,
229 struct lwtunnel_state *lwtstate,
230 int encap_attr, int encap_type_attr)
231 {
232 return 0;
233 }
234
lwtunnel_get_encap_size(struct lwtunnel_state * lwtstate)235 static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
236 {
237 return 0;
238 }
239
lwtunnel_state_alloc(int hdr_len)240 static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
241 {
242 return NULL;
243 }
244
lwtunnel_cmp_encap(struct lwtunnel_state * a,struct lwtunnel_state * b)245 static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
246 struct lwtunnel_state *b)
247 {
248 return 0;
249 }
250
lwtunnel_output(struct net * net,struct sock * sk,struct sk_buff * skb)251 static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
252 {
253 return -EOPNOTSUPP;
254 }
255
lwtunnel_input(struct sk_buff * skb)256 static inline int lwtunnel_input(struct sk_buff *skb)
257 {
258 return -EOPNOTSUPP;
259 }
260
lwtunnel_xmit(struct sk_buff * skb)261 static inline int lwtunnel_xmit(struct sk_buff *skb)
262 {
263 return -EOPNOTSUPP;
264 }
265
266 #endif /* CONFIG_LWTUNNEL */
267
268 #define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
269
270 #endif /* __NET_LWTUNNEL_H */
271