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[0];
  34 };
  35
  36 struct lwtunnel_encap_ops {
  37         int (*build_state)(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 void lwtstate_free(struct lwtunnel_state *lws);
  55
  56 static inline struct lwtunnel_state *
  57 lwtstate_get(struct lwtunnel_state *lws)
  58 {
  59         if (lws)
  60                 atomic_inc(&lws->refcnt);
  61
  62         return lws;
  63 }
  64
  65 static inline void lwtstate_put(struct lwtunnel_state *lws)
  66 {
  67         if (!lws)
  68                 return;
  69
  70         if (atomic_dec_and_test(&lws->refcnt))
  71                 lwtstate_free(lws);
  72 }
  73
  74 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
  75 {
  76         if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_OUTPUT_REDIRECT))
  77                 return true;
  78
  79         return false;
  80 }
  81
  82 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
  83 {
  84         if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_INPUT_REDIRECT))
  85                 return true;
  86
  87         return false;
  88 }
  89
  90 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
  91 {
  92         if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_XMIT_REDIRECT))
  93                 return true;
  94
  95         return false;
  96 }
  97
  98 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
  99                                              unsigned int mtu)
 100 {
 101         if ((lwtunnel_xmit_redirect(lwtstate) ||
 102              lwtunnel_output_redirect(lwtstate)) && lwtstate->headroom < mtu)
 103                 return lwtstate->headroom;
 104
 105         return 0;
 106 }
 107
 108 int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
 109                            unsigned int num);
 110 int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
 111                            unsigned int num);
 112 int lwtunnel_valid_encap_type(u16 encap_type,
 113                               struct netlink_ext_ack *extack);
 114 int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
 115                                    struct netlink_ext_ack *extack);
 116 int lwtunnel_build_state(u16 encap_type,
 117                          struct nlattr *encap,
 118                          unsigned int family, const void *cfg,
 119                          struct lwtunnel_state **lws,
 120                          struct netlink_ext_ack *extack);
 121 int lwtunnel_fill_encap(struct sk_buff *skb,
 122                         struct lwtunnel_state *lwtstate);
 123 int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
 124 struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len);
 125 int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b);
 126 int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 127 int lwtunnel_input(struct sk_buff *skb);
 128 int lwtunnel_xmit(struct sk_buff *skb);
 129
 130 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
 131 {
 132         if (lwtunnel_output_redirect(dst->lwtstate)) {
 133                 dst->lwtstate->orig_output = dst->output;
 134                 dst->output = lwtunnel_output;
 135         }
 136         if (lwtunnel_input_redirect(dst->lwtstate)) {
 137                 dst->lwtstate->orig_input = dst->input;
 138                 dst->input = lwtunnel_input;
 139         }
 140 }
 141 #else
 142
 143 static inline void lwtstate_free(struct lwtunnel_state *lws)
 144 {
 145 }
 146
 147 static inline struct lwtunnel_state *
 148 lwtstate_get(struct lwtunnel_state *lws)
 149 {
 150         return lws;
 151 }
 152
 153 static inline void lwtstate_put(struct lwtunnel_state *lws)
 154 {
 155 }
 156
 157 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
 158 {
 159         return false;
 160 }
 161
 162 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
 163 {
 164         return false;
 165 }
 166
 167 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
 168 {
 169         return false;
 170 }
 171
 172 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
 173 {
 174 }
 175
 176 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
 177                                              unsigned int mtu)
 178 {
 179         return 0;
 180 }
 181
 182 static inline int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
 183                                          unsigned int num)
 184 {
 185         return -EOPNOTSUPP;
 186
 187 }
 188
 189 static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
 190                                          unsigned int num)
 191 {
 192         return -EOPNOTSUPP;
 193 }
 194
 195 static inline int lwtunnel_valid_encap_type(u16 encap_type,
 196                                             struct netlink_ext_ack *extack)
 197 {
 198         NL_SET_ERR_MSG(extack, "CONFIG_LWTUNNEL is not enabled in this kernel");
 199         return -EOPNOTSUPP;
 200 }
 201 static inline int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
 202                                                  struct netlink_ext_ack *extack)
 203 {
 204         /* return 0 since we are not walking attr looking for
 205          * RTA_ENCAP_TYPE attribute on nexthops.
 206          */
 207         return 0;
 208 }
 209
 210 static inline int lwtunnel_build_state(u16 encap_type,
 211                                        struct nlattr *encap,
 212                                        unsigned int family, const void *cfg,
 213                                        struct lwtunnel_state **lws,
 214                                        struct netlink_ext_ack *extack)
 215 {
 216         return -EOPNOTSUPP;
 217 }
 218
 219 static inline int lwtunnel_fill_encap(struct sk_buff *skb,
 220                                       struct lwtunnel_state *lwtstate)
 221 {
 222         return 0;
 223 }
 224
 225 static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
 226 {
 227         return 0;
 228 }
 229
 230 static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
 231 {
 232         return NULL;
 233 }
 234
 235 static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
 236                                      struct lwtunnel_state *b)
 237 {
 238         return 0;
 239 }
 240
 241 static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 242 {
 243         return -EOPNOTSUPP;
 244 }
 245
 246 static inline int lwtunnel_input(struct sk_buff *skb)
 247 {
 248         return -EOPNOTSUPP;
 249 }
 250
 251 static inline int lwtunnel_xmit(struct sk_buff *skb)
 252 {
 253         return -EOPNOTSUPP;
 254 }
 255
 256 #endif /* CONFIG_LWTUNNEL */
 257
 258 #define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
 259
 260 #endif /* __NET_LWTUNNEL_H */