lwtunnel.h

  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 */