Introduce helpers to let eBPF programs attached to TC manipulate tunnel metadata: bpf_skb_[gs]et_tunnel_key(skb, key, size, flags) skb: pointer to skb key: pointer to 'struct bpf_tunnel_key' size: size of 'struct bpf_tunnel_key' flags: room for future extensions First eBPF program that uses these helpers will allocate per_cpu metadata_dst structures that will be used on TX. On RX metadata_dst is allocated by tunnel driver. Typical usage for TX: struct bpf_tunnel_key tkey; ... populate tkey ... bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), 0); bpf_clone_redirect(skb, vxlan_dev_ifindex, 0); RX: struct bpf_tunnel_key tkey = {}; bpf_skb_get_tunnel_key(skb, &tkey, sizeof(tkey), 0); ... lookup or redirect based on tkey ... 'struct bpf_tunnel_key' will be extended in the future by adding elements to the end and the 'size' argument will indicate which fields are populated, thereby keeping backwards compatibility. The 'flags' argument may be used as well when the 'size' is not enough or to indicate completely different layout of bpf_tunnel_key.
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| @@ -258,6 +258,18 @@ enum bpf_func_id { · 257 unmodified lines | ||
| 258 | 258 | BPF_FUNC_get_cgroup_classid, |
| 259 | 259 | BPF_FUNC_skb_vlan_push, /* bpf_skb_vlan_push(skb, vlan_proto, vlan_tci) */ |
| 260 | 260 | BPF_FUNC_skb_vlan_pop, /* bpf_skb_vlan_pop(skb) */ |
| 261 | + | |
| 262 | + /** | |
| 263 | + * bpf_skb_[gs]et_tunnel_key(skb, key, size, flags) | |
| 264 | + * retrieve or populate tunnel metadata | |
| 265 | + * @skb: pointer to skb | |
| 266 | + * @key: pointer to 'struct bpf_tunnel_key' | |
| 267 | + * @size: size of 'struct bpf_tunnel_key' | |
| 268 | + * @flags: room for future extensions | |
| 269 | + * Retrun: 0 on success | |
| 270 | + */ | |
| 271 | + BPF_FUNC_skb_get_tunnel_key, | |
| 272 | + BPF_FUNC_skb_set_tunnel_key, | |
| 261 | 273 | __BPF_FUNC_MAX_ID, |
| 262 | 274 | }; |
| 263 | 275 | |
| @@ -280,4 +292,9 @@ struct __sk_buff { · 16 unmodified lines | ||
| 280 | 292 | __u32 cb[5]; |
| 281 | 293 | }; |
| 282 | 294 | |
| 295 | +struct bpf_tunnel_key { | |
| 296 | + __u32 tunnel_id; | |
| 297 | + __u32 remote_ipv4; | |
| 298 | +}; | |
| 299 | + | |
| 283 | 300 | #endif /* _UAPI__LINUX_BPF_H__ */ |