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 /* 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 *
  63 lwtstate_get(struct lwtunnel_state *lws)
  64 {
  65         if (lws)
  66                 atomic_inc(&lws->refcnt);
  67
  68         return lws;
  69 }
  70
  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
  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
  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
  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
 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
 138 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
 139 {
 140         if (lwtunnel_output_redirect(dst->lwtstate)) {
 141                 dst->lwtstate->orig_output = dst->output;
 142                 dst->output = lwtunnel_output;
 143         }
 144         if (lwtunnel_input_redirect(dst->lwtstate)) {
 145                 dst->lwtstate->orig_input = dst->input;
 146                 dst->input = lwtunnel_input;
 147         }
 148 }
 149 #else
 150
 151 static inline void lwtstate_free(struct lwtunnel_state *lws)
 152 {
 153 }
 154
 155 static inline struct lwtunnel_state *
 156 lwtstate_get(struct lwtunnel_state *lws)
 157 {
 158         return lws;
 159 }
 160
 161 static inline void lwtstate_put(struct lwtunnel_state *lws)
 162 {
 163 }
 164
 165 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
 166 {
 167         return false;
 168 }
 169
 170 static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
 171 {
 172         return false;
 173 }
 174
 175 static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
 176 {
 177         return false;
 178 }
 179
 180 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
 181 {
 182 }
 183
 184 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
 185                                              unsigned int mtu)
 186 {
 187         return 0;
 188 }
 189
 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
 197 static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
 198                                          unsigned int num)
 199 {
 200         return -EOPNOTSUPP;
 201 }
 202
 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 static inline int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
 210                                                  struct netlink_ext_ack *extack)
 211 {
 212         /* return 0 since we are not walking attr looking for
 213          * RTA_ENCAP_TYPE attribute on nexthops.
 214          */
 215         return 0;
 216 }
 217
 218 static inline int lwtunnel_build_state(struct net *net, u16 encap_type,
 219                                        struct nlattr *encap,
 220                                        unsigned int family, const void *cfg,
 221                                        struct lwtunnel_state **lws,
 222                                        struct netlink_ext_ack *extack)
 223 {
 224         return -EOPNOTSUPP;
 225 }
 226
 227 static inline int lwtunnel_fill_encap(struct sk_buff *skb,
 228                                       struct lwtunnel_state *lwtstate,
 229                                       int encap_attr, int encap_type_attr)
 230 {
 231         return 0;
 232 }
 233
 234 static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
 235 {
 236         return 0;
 237 }
 238
 239 static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
 240 {
 241         return NULL;
 242 }
 243
 244 static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
 245                                      struct lwtunnel_state *b)
 246 {
 247         return 0;
 248 }
 249
 250 static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 251 {
 252         return -EOPNOTSUPP;
 253 }
 254
 255 static inline int lwtunnel_input(struct sk_buff *skb)
 256 {
 257         return -EOPNOTSUPP;
 258 }
 259
 260 static inline int lwtunnel_xmit(struct sk_buff *skb)
 261 {
 262         return -EOPNOTSUPP;
 263 }
 264
 265 #endif /* CONFIG_LWTUNNEL */
 266
 267 #define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
 268
 269 #endif /* __NET_LWTUNNEL_H */