Re: [PATCHv4 bpf-next 1/2] xdp: add a new helper for dev map multicast support

["Toke Høiland-Jørgensen" <toke@redhat.com>]

Hangbin Liu <liuhangbin@gmail.com> writes:

> This patch is for xdp multicast support. In this implementation we
> add a new helper to accept two maps: forward map and exclude map.
> We will redirect the packet to all the interfaces in *forward map*, but
> exclude the interfaces that in *exclude map*.
>
> To achive this I add a new ex_map for struct bpf_redirect_info.
> in the helper I set tgt_value to NULL to make a difference with
> bpf_xdp_redirect_map()
>
> We also add a flag *BPF_F_EXCLUDE_INGRESS* incase you don't want to
> create a exclude map for each interface and just want to exclude the
> ingress interface.
>
> The general data path is kept in net/core/filter.c. The native data
> path is in kernel/bpf/devmap.c so we can use direct calls to
> get better performace.
>
> v4: Fix bpf_xdp_redirect_map_multi_proto arg2_type typo
>
> v3: Based on Toke's suggestion, do the following update
> a) Update bpf_redirect_map_multi() description in bpf.h.
> b) Fix exclude_ifindex checking order in dev_in_exclude_map().
> c) Fix one more xdpf clone in dev_map_enqueue_multi().
> d) Go find next one in dev_map_enqueue_multi() if the interface is not
>    able to forward instead of abort the whole loop.
> e) Remove READ_ONCE/WRITE_ONCE for ex_map.
>
> v2: Add new syscall bpf_xdp_redirect_map_multi() which could accept
> include/exclude maps directly.
>
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> ---
>  include/linux/bpf.h            |  20 ++++++
>  include/linux/filter.h         |   1 +
>  include/net/xdp.h              |   1 +
>  include/uapi/linux/bpf.h       |  22 +++++-
>  kernel/bpf/devmap.c            | 124 +++++++++++++++++++++++++++++++++
>  kernel/bpf/verifier.c          |   6 ++
>  net/core/filter.c              | 101 +++++++++++++++++++++++++--
>  net/core/xdp.c                 |  26 +++++++
>  tools/include/uapi/linux/bpf.h |  22 +++++-
>  9 files changed, 316 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index efe8836b5c48..d1c169bec6b5 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1240,6 +1240,11 @@ int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
>  		    struct net_device *dev_rx);
>  int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
>  		    struct net_device *dev_rx);
> +bool dev_in_exclude_map(struct bpf_dtab_netdev *obj, struct bpf_map *map,
> +			int exclude_ifindex);
> +int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
> +			  struct bpf_map *map, struct bpf_map *ex_map,
> +			  bool exclude_ingress);
>  int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
>  			     struct bpf_prog *xdp_prog);
>  
> @@ -1377,6 +1382,21 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
>  	return 0;
>  }
>  
> +static inline
> +bool dev_in_exclude_map(struct bpf_dtab_netdev *obj, struct bpf_map *map,
> +			int exclude_ifindex)
> +{
> +	return false;
> +}
> +
> +static inline
> +int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
> +			  struct bpf_map *map, struct bpf_map *ex_map,
> +			  bool exclude_ingress)
> +{
> +	return 0;
> +}
> +
>  struct sk_buff;
>  
>  static inline int dev_map_generic_redirect(struct bpf_dtab_netdev *dst,
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index 73d06a39e2d6..5d9c6ac6ade3 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -612,6 +612,7 @@ struct bpf_redirect_info {
>  	u32 tgt_index;
>  	void *tgt_value;
>  	struct bpf_map *map;
> +	struct bpf_map *ex_map;
>  	u32 kern_flags;
>  };
>  
> diff --git a/include/net/xdp.h b/include/net/xdp.h
> index 90f11760bd12..967684aa096a 100644
> --- a/include/net/xdp.h
> +++ b/include/net/xdp.h
> @@ -105,6 +105,7 @@ void xdp_warn(const char *msg, const char *func, const int line);
>  #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)
>  
>  struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
> +struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf);
>  
>  /* Convert xdp_buff to xdp_frame */
>  static inline
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 97e1fd19ff58..000b0cf961ea 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -3157,6 +3157,20 @@ union bpf_attr {
>   *		**bpf_sk_cgroup_id**\ ().
>   *	Return
>   *		The id is returned or 0 in case the id could not be retrieved.
> + *
> + * int bpf_redirect_map_multi(struct bpf_map *map, struct bpf_map *ex_map, u64 flags)
> + * 	Description
> + * 		Redirect the packet to ALL the interfaces in *map*, but
> + * 		exclude the interfaces in *ex_map* (which may be NULL).
> + *
> + * 		Currently the *flags* only supports *BPF_F_EXCLUDE_INGRESS*,
> + * 		which additionally excludes the current ingress device.
> + *
> + * 		See also bpf_redirect_map(), which supports redirecting
> + * 		packet to a specific ifindex in the map.
> + * 	Return
> + * 		**XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
> + *
>   */
>  #define __BPF_FUNC_MAPPER(FN)		\
>  	FN(unspec),			\
> @@ -3288,7 +3302,8 @@ union bpf_attr {
>  	FN(seq_printf),			\
>  	FN(seq_write),			\
>  	FN(sk_cgroup_id),		\
> -	FN(sk_ancestor_cgroup_id),
> +	FN(sk_ancestor_cgroup_id),	\
> +	FN(redirect_map_multi),
>  
>  /* integer value in 'imm' field of BPF_CALL instruction selects which helper
>   * function eBPF program intends to call
> @@ -3417,6 +3432,11 @@ enum bpf_lwt_encap_mode {
>  	BPF_LWT_ENCAP_IP,
>  };
>  
> +/* BPF_FUNC_redirect_map_multi flags. */
> +enum {
> +	BPF_F_EXCLUDE_INGRESS		= (1ULL << 0),
> +};
> +
>  #define __bpf_md_ptr(type, name)	\
>  union {					\
>  	type name;			\
> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
> index a51d9fb7a359..ecc5c44a5bab 100644
> --- a/kernel/bpf/devmap.c
> +++ b/kernel/bpf/devmap.c
> @@ -455,6 +455,130 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
>  	return __xdp_enqueue(dev, xdp, dev_rx);
>  }
>  
> +/* Use direct call in fast path instead of  map->ops->map_get_next_key() */
> +static int devmap_get_next_key(struct bpf_map *map, void *key, void *next_key)
> +{
> +
> +	switch (map->map_type) {
> +	case BPF_MAP_TYPE_DEVMAP:
> +		return dev_map_get_next_key(map, key, next_key);
> +	case BPF_MAP_TYPE_DEVMAP_HASH:
> +		return dev_map_hash_get_next_key(map, key, next_key);
> +	default:
> +		break;
> +	}
> +
> +	return -ENOENT;
> +}
> +
> +bool dev_in_exclude_map(struct bpf_dtab_netdev *obj, struct bpf_map *map,
> +			int exclude_ifindex)
> +{
> +	struct bpf_dtab_netdev *in_obj = NULL;
> +	u32 key, next_key;
> +	int err;
> +
> +	if (obj->dev->ifindex == exclude_ifindex)
> +		return true;
> +
> +	if (!map)
> +		return false;
> +
> +	devmap_get_next_key(map, NULL, &key);

You also need to check if this fails; the map could be empty... This
goes for all the places you loop through maps below, but not going to
repeat the comment :)

> +	for (;;) {
> +		switch (map->map_type) {
> +		case BPF_MAP_TYPE_DEVMAP:
> +			in_obj = __dev_map_lookup_elem(map, key);
> +			break;
> +		case BPF_MAP_TYPE_DEVMAP_HASH:
> +			in_obj = __dev_map_hash_lookup_elem(map, key);
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		if (in_obj && in_obj->dev->ifindex == obj->dev->ifindex)
> +			return true;
> +
> +		err = devmap_get_next_key(map, &key, &next_key);
> +
> +		if (err)
> +			break;
> +
> +		key = next_key;
> +	}
> +
> +	return false;
> +}
> +
> +int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
> +			  struct bpf_map *map, struct bpf_map *ex_map,
> +			  bool exclude_ingress)
> +{
> +	struct bpf_dtab_netdev *obj = NULL;
> +	struct xdp_frame *xdpf, *nxdpf;
> +	struct net_device *dev;
> +	bool first = true;
> +	u32 key, next_key;
> +	int err;
> +
> +	devmap_get_next_key(map, NULL, &key);
> +
> +	xdpf = convert_to_xdp_frame(xdp);
> +	if (unlikely(!xdpf))
> +		return -EOVERFLOW;
> +
> +	for (;;) {
> +		switch (map->map_type) {
> +		case BPF_MAP_TYPE_DEVMAP:
> +			obj = __dev_map_lookup_elem(map, key);
> +			break;
> +		case BPF_MAP_TYPE_DEVMAP_HASH:
> +			obj = __dev_map_hash_lookup_elem(map, key);
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		if (!obj || dev_in_exclude_map(obj, ex_map,
> +					       exclude_ingress ? dev_rx->ifindex : 0))
> +			goto find_next;
> +
> +		dev = obj->dev;
> +
> +		if (!dev->netdev_ops->ndo_xdp_xmit)
> +			goto find_next;
> +
> +		err = xdp_ok_fwd_dev(dev, xdp->data_end - xdp->data);
> +		if (unlikely(err))
> +			goto find_next;
> +
> +		if (!first) {
> +			nxdpf = xdpf_clone(xdpf);
> +			if (unlikely(!nxdpf))
> +				return -ENOMEM;
> +
> +			bq_enqueue(dev, nxdpf, dev_rx);
> +		} else {
> +			bq_enqueue(dev, xdpf, dev_rx);
> +			first = false;
> +		}
> +
> +find_next:
> +		err = devmap_get_next_key(map, &key, &next_key);
> +		if (err)
> +			break;
> +		key = next_key;
> +	}
> +
> +	/* didn't find anywhere to forward to, free buf */
> +	if (first)
> +		xdp_return_frame_rx_napi(xdpf);
> +
> +	return 0;
> +}
> +
>  int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
>  			     struct bpf_prog *xdp_prog)
>  {
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index d2e27dba4ac6..a5857953248d 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -3946,6 +3946,7 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
>  	case BPF_MAP_TYPE_DEVMAP:
>  	case BPF_MAP_TYPE_DEVMAP_HASH:
>  		if (func_id != BPF_FUNC_redirect_map &&
> +		    func_id != BPF_FUNC_redirect_map_multi &&
>  		    func_id != BPF_FUNC_map_lookup_elem)
>  			goto error;
>  		break;
> @@ -4038,6 +4039,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
>  		    map->map_type != BPF_MAP_TYPE_XSKMAP)
>  			goto error;
>  		break;
> +	case BPF_FUNC_redirect_map_multi:
> +		if (map->map_type != BPF_MAP_TYPE_DEVMAP &&
> +		    map->map_type != BPF_MAP_TYPE_DEVMAP_HASH)
> +			goto error;
> +		break;
>  	case BPF_FUNC_sk_redirect_map:
>  	case BPF_FUNC_msg_redirect_map:
>  	case BPF_FUNC_sock_map_update:
> diff --git a/net/core/filter.c b/net/core/filter.c
> index bd2853d23b50..f07eb1408f70 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -3473,12 +3473,17 @@ static const struct bpf_func_proto bpf_xdp_adjust_meta_proto = {
>  };
>  
>  static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd,
> -			    struct bpf_map *map, struct xdp_buff *xdp)
> +			    struct bpf_map *map, struct xdp_buff *xdp,
> +			    struct bpf_map *ex_map, bool exclude_ingress)

Maybe just pass through the flags argument here?

>  {
>  	switch (map->map_type) {
>  	case BPF_MAP_TYPE_DEVMAP:
>  	case BPF_MAP_TYPE_DEVMAP_HASH:
> -		return dev_map_enqueue(fwd, xdp, dev_rx);

Using a NULL target_value to distinguish between multicast and unicast
forwarding is clever, but bordering on 'too clever' :) - took me a
little while to figure out this was what you were doing, at least. So
please add a comment explaining this, here and in the helper.

> +		if (fwd)
> +			return dev_map_enqueue(fwd, xdp, dev_rx);
> +		else
> +			return dev_map_enqueue_multi(xdp, dev_rx, map, ex_map,
> +						     exclude_ingress);
>  	case BPF_MAP_TYPE_CPUMAP:
>  		return cpu_map_enqueue(fwd, xdp, dev_rx);
>  	case BPF_MAP_TYPE_XSKMAP:
> @@ -3534,6 +3539,8 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
>  		    struct bpf_prog *xdp_prog)
>  {
>  	struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
> +	bool exclude_ingress = !!(ri->flags & BPF_F_EXCLUDE_INGRESS);
> +	struct bpf_map *ex_map = ri->ex_map;
>  	struct bpf_map *map = READ_ONCE(ri->map);
>  	u32 index = ri->tgt_index;
>  	void *fwd = ri->tgt_value;
> @@ -3541,6 +3548,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
>  
>  	ri->tgt_index = 0;
>  	ri->tgt_value = NULL;
> +	ri->ex_map = NULL;
>  	WRITE_ONCE(ri->map, NULL);
>  
>  	if (unlikely(!map)) {
> @@ -3552,7 +3560,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
>  
>  		err = dev_xdp_enqueue(fwd, xdp, dev);
>  	} else {
> -		err = __bpf_tx_xdp_map(dev, fwd, map, xdp);
> +		err = __bpf_tx_xdp_map(dev, fwd, map, xdp, ex_map, exclude_ingress);
>  	}
>  
>  	if (unlikely(err))
> @@ -3566,6 +3574,50 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
>  }
>  EXPORT_SYMBOL_GPL(xdp_do_redirect);
>  
> +static int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
> +				  struct bpf_prog *xdp_prog,
> +				  struct bpf_map *map, struct bpf_map *ex_map,
> +				  bool exclude_ingress)
> +
> +{
> +	struct bpf_dtab_netdev *dst;
> +	struct sk_buff *nskb;
> +	u32 key, next_key;
> +	int err;
> +	void *fwd;
> +
> +	/* Get first key from forward map */
> +	map->ops->map_get_next_key(map, NULL, &key);
> +
> +	for (;;) {
> +		fwd = __xdp_map_lookup_elem(map, key);
> +		if (fwd) {
> +			dst = (struct bpf_dtab_netdev *)fwd;
> +			if (dev_in_exclude_map(dst, ex_map,
> +					       exclude_ingress ? dev->ifindex : 0))
> +				goto find_next;
> +
> +			nskb = skb_clone(skb, GFP_ATOMIC);
> +			if (!nskb)
> +				return -ENOMEM;
> +
> +			err = dev_map_generic_redirect(dst, nskb, xdp_prog);
> +			if (unlikely(err))
> +				return err;
> +		}
> +
> +find_next:
> +		err = map->ops->map_get_next_key(map, &key, &next_key);
> +		if (err)
> +			break;
> +
> +		key = next_key;
> +	}
> +
> +	consume_skb(skb);
> +	return 0;
> +}
> +
>  static int xdp_do_generic_redirect_map(struct net_device *dev,
>  				       struct sk_buff *skb,
>  				       struct xdp_buff *xdp,
> @@ -3573,19 +3625,29 @@ static int xdp_do_generic_redirect_map(struct net_device *dev,
>  				       struct bpf_map *map)
>  {
>  	struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
> +	bool exclude_ingress = !!(ri->flags & BPF_F_EXCLUDE_INGRESS);
> +	struct bpf_map *ex_map = ri->ex_map;
>  	u32 index = ri->tgt_index;
>  	void *fwd = ri->tgt_value;
>  	int err = 0;
>  
>  	ri->tgt_index = 0;
>  	ri->tgt_value = NULL;
> +	ri->ex_map = NULL;
>  	WRITE_ONCE(ri->map, NULL);
>  
>  	if (map->map_type == BPF_MAP_TYPE_DEVMAP ||
>  	    map->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
> -		struct bpf_dtab_netdev *dst = fwd;

Same as above - please add a comment explaining this test...

> +		if (fwd) {
> +			struct bpf_dtab_netdev *dst = fwd;
> +
> +			err = dev_map_generic_redirect(dst, skb, xdp_prog);
> +		} else {
> +			/* Deal with multicast maps */
> +			err = dev_map_redirect_multi(dev, skb, xdp_prog, map,
> +						     ex_map, exclude_ingress);
> +		}
>  
> -		err = dev_map_generic_redirect(dst, skb, xdp_prog);
>  		if (unlikely(err))
>  			goto err;
>  	} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
> @@ -3699,6 +3761,33 @@ static const struct bpf_func_proto bpf_xdp_redirect_map_proto = {
>  	.arg3_type      = ARG_ANYTHING,
>  };
>  
> +BPF_CALL_3(bpf_xdp_redirect_map_multi, struct bpf_map *, map,
> +	   struct bpf_map *, ex_map, u64, flags)
> +{
> +	struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
> +
> +	if (unlikely(!map || flags > BPF_F_EXCLUDE_INGRESS))
> +		return XDP_ABORTED;
> +
> +	ri->tgt_index = 0;
> +	ri->tgt_value = NULL;
> +	ri->flags = flags;
> +	ri->ex_map = ex_map;
> +
> +	WRITE_ONCE(ri->map, map);
> +
> +	return XDP_REDIRECT;
> +}
> +
> +static const struct bpf_func_proto bpf_xdp_redirect_map_multi_proto = {
> +	.func           = bpf_xdp_redirect_map_multi,
> +	.gpl_only       = false,
> +	.ret_type       = RET_INTEGER,
> +	.arg1_type      = ARG_CONST_MAP_PTR,
> +	.arg2_type      = ARG_CONST_MAP_PTR,
> +	.arg3_type      = ARG_ANYTHING,
> +};
> +
>  static unsigned long bpf_skb_copy(void *dst_buff, const void *skb,
>  				  unsigned long off, unsigned long len)
>  {
> @@ -6363,6 +6452,8 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
>  		return &bpf_xdp_redirect_proto;
>  	case BPF_FUNC_redirect_map:
>  		return &bpf_xdp_redirect_map_proto;
> +	case BPF_FUNC_redirect_map_multi:
> +		return &bpf_xdp_redirect_map_multi_proto;
>  	case BPF_FUNC_xdp_adjust_tail:
>  		return &bpf_xdp_adjust_tail_proto;
>  	case BPF_FUNC_fib_lookup:
> diff --git a/net/core/xdp.c b/net/core/xdp.c
> index 90f44f382115..acdc63833b1f 100644
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c
> @@ -475,3 +475,29 @@ void xdp_warn(const char *msg, const char *func, const int line)
>  	WARN(1, "XDP_WARN: %s(line:%d): %s\n", func, line, msg);
>  };
>  EXPORT_SYMBOL_GPL(xdp_warn);
> +
> +struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf)
> +{
> +	unsigned int headroom, totalsize;
> +	struct xdp_frame *nxdpf;
> +	struct page *page;
> +	void *addr;
> +
> +	headroom = xdpf->headroom + sizeof(*xdpf);
> +	totalsize = headroom + xdpf->len;
> +
> +	if (unlikely(totalsize > PAGE_SIZE))
> +		return NULL;
> +	page = dev_alloc_page();
> +	if (!page)
> +		return NULL;
> +	addr = page_to_virt(page);
> +
> +	memcpy(addr, xdpf, totalsize);
> +
> +	nxdpf = addr;
> +	nxdpf->data = addr + headroom;
> +
> +	return nxdpf;
> +}
> +EXPORT_SYMBOL_GPL(xdpf_clone);
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 97e1fd19ff58..000b0cf961ea 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -3157,6 +3157,20 @@ union bpf_attr {
>   *		**bpf_sk_cgroup_id**\ ().
>   *	Return
>   *		The id is returned or 0 in case the id could not be retrieved.
> + *
> + * int bpf_redirect_map_multi(struct bpf_map *map, struct bpf_map *ex_map, u64 flags)
> + * 	Description
> + * 		Redirect the packet to ALL the interfaces in *map*, but
> + * 		exclude the interfaces in *ex_map* (which may be NULL).
> + *
> + * 		Currently the *flags* only supports *BPF_F_EXCLUDE_INGRESS*,
> + * 		which additionally excludes the current ingress device.
> + *
> + * 		See also bpf_redirect_map(), which supports redirecting
> + * 		packet to a specific ifindex in the map.
> + * 	Return
> + * 		**XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
> + *
>   */
>  #define __BPF_FUNC_MAPPER(FN)		\
>  	FN(unspec),			\
> @@ -3288,7 +3302,8 @@ union bpf_attr {
>  	FN(seq_printf),			\
>  	FN(seq_write),			\
>  	FN(sk_cgroup_id),		\
> -	FN(sk_ancestor_cgroup_id),
> +	FN(sk_ancestor_cgroup_id),	\
> +	FN(redirect_map_multi),
>  
>  /* integer value in 'imm' field of BPF_CALL instruction selects which helper
>   * function eBPF program intends to call
> @@ -3417,6 +3432,11 @@ enum bpf_lwt_encap_mode {
>  	BPF_LWT_ENCAP_IP,
>  };
>  
> +/* BPF_FUNC_redirect_map_multi flags. */
> +enum {
> +	BPF_F_EXCLUDE_INGRESS		= (1ULL << 0),
> +};
> +
>  #define __bpf_md_ptr(type, name)	\
>  union {					\
>  	type name;			\
> -- 
> 2.25.4