include/net/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 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 *
  60 lwtstate_get(struct lwtunnel_state *lws)
  61 {
  62         if (lws)
  63                 atomic_inc(&lws->refcnt);
  64
  65         return lws;
  66 }
  67
  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
  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
  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
  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
 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
 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
 148 static inline void lwtstate_free(struct lwtunnel_state *lws)
 149 {
 150 }
 151
 152 static inline struct lwtunnel_state *
 153 lwtstate_get(struct lwtunnel_state *lws)
 154 {
 155         return lws;
 156 }
 157
 158 static inline void lwtstate_put(struct lwtunnel_state *lws)
 159 {
 160 }
 161
 162 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
 163 {
 164         return false;
 165 }
 166
 167 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
 168 {
 169         return false;
 170 }
 171
 172 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
 173 {
 174         return false;
 175 }
 176
 177 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
 178 {
 179 }
 180
 181 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
 182                                              unsigned int mtu)
 183 {
 184         return 0;
 185 }
 186
 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
 194 static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
 195                                          unsigned int num)
 196 {
 197         return -EOPNOTSUPP;
 198 }
 199
 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 }
 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
 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
 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
 231 static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
 232 {
 233         return 0;
 234 }
 235
 236 static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
 237 {
 238         return NULL;
 239 }
 240
 241 static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
 242                                      struct lwtunnel_state *b)
 243 {
 244         return 0;
 245 }
 246
 247 static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 248 {
 249         return -EOPNOTSUPP;
 250 }
 251
 252 static inline int lwtunnel_input(struct sk_buff *skb)
 253 {
 254         return -EOPNOTSUPP;
 255 }
 256
 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 */