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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 */
22enum {
23 LWTUNNEL_XMIT_DONE,
24 LWTUNNEL_XMIT_CONTINUE = 0x100,
25};
26
27
28struct 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
39struct 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
58DECLARE_STATIC_KEY_FALSE(nf_hooks_lwtunnel_enabled);
59
60void lwtstate_free(struct lwtunnel_state *lws);
61
62static inline struct lwtunnel_state *
63lwtstate_get(struct lwtunnel_state *lws)
64{
65 if (lws)
66 atomic_inc(&lws->refcnt);
67
68 return lws;
69}
70
71static 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
80static 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
88static 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
96static 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
104static 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
114int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
115 unsigned int num);
116int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
117 unsigned int num);
118int lwtunnel_valid_encap_type(u16 encap_type,
119 struct netlink_ext_ack *extack);
120int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
121 struct netlink_ext_ack *extack);
122int 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);
127int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate,
128 int encap_attr, int encap_type_attr);
129int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
130struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len);
131int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b);
132int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb);
133int lwtunnel_input(struct sk_buff *skb);
134int lwtunnel_xmit(struct sk_buff *skb);
135int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len,
136 bool ingress);
137
138static 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
151static inline void lwtstate_free(struct lwtunnel_state *lws)
152{
153}
154
155static inline struct lwtunnel_state *
156lwtstate_get(struct lwtunnel_state *lws)
157{
158 return lws;
159}
160
161static inline void lwtstate_put(struct lwtunnel_state *lws)
162{
163}
164
165static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
166{
167 return false;
168}
169
170static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
171{
172 return false;
173}
174
175static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
176{
177 return false;
178}
179
180static inline void lwtunnel_set_redirect(struct dst_entry *dst)
181{
182}
183
184static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
185 unsigned int mtu)
186{
187 return 0;
188}
189
190static inline int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
191 unsigned int num)
192{
193 return -EOPNOTSUPP;
194
195}
196
197static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
198 unsigned int num)
199{
200 return -EOPNOTSUPP;
201}
202
203static 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
210static 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
219static 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
228static 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
235static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
236{
237 return 0;
238}
239
240static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
241{
242 return NULL;
243}
244
245static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
246 struct lwtunnel_state *b)
247{
248 return 0;
249}
250
251static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
252{
253 return -EOPNOTSUPP;
254}
255
256static inline int lwtunnel_input(struct sk_buff *skb)
257{
258 return -EOPNOTSUPP;
259}
260
261static 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 */