Commit 0165cc81 authored by Lorenzo Bianconi's avatar Lorenzo Bianconi Committed by Alexei Starovoitov
Browse files

bpf: introduce bpf_xdp_get_buff_len helper 



Introduce bpf_xdp_get_buff_len helper in order to return the xdp buffer
total size (linear and paged area)

Acked-by: default avatarToke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: default avatarLorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/aac9ac3504c84026cf66a3c71b7c5ae89bc991be.1642758637.git.lorenzo@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent e121d270

include/net/xdp.h

+14 −0
Original line number Diff line number Diff line
@@ -145,6 +145,20 @@ xdp_get_shared_info_from_buff(struct xdp_buff *xdp) 
	return (struct skb_shared_info *)xdp_data_hard_end(xdp);

}



static __always_inline unsigned int xdp_get_buff_len(struct xdp_buff *xdp)

{

	unsigned int len = xdp->data_end - xdp->data;

	struct skb_shared_info *sinfo;



	if (likely(!xdp_buff_has_frags(xdp)))

		goto out;



	sinfo = xdp_get_shared_info_from_buff(xdp);

	len += sinfo->xdp_frags_size;

out:

	return len;

}



struct xdp_frame {

	void *data;

	u16 len;

include/uapi/linux/bpf.h

+7 −0
Original line number Diff line number Diff line
@@ -5054,6 +5054,12 @@ union bpf_attr { 
 *		This helper is currently supported by cgroup programs only.

 *	Return

 *		0 on success, or a negative error in case of failure.

 *

 * u64 bpf_xdp_get_buff_len(struct xdp_buff *xdp_md)

 *	Description

 *		Get the total size of a given xdp buff (linear and paged area)

 *	Return

 *		The total size of a given xdp buffer.

 */

#define __BPF_FUNC_MAPPER(FN)		\

	FN(unspec),			\
@@ -5244,6 +5250,7 @@ union bpf_attr { 
	FN(get_func_arg_cnt),		\

	FN(get_retval),			\

	FN(set_retval),			\

	FN(xdp_get_buff_len),		\

	/* */



/* integer value in 'imm' field of BPF_CALL instruction selects which helper

net/core/filter.c

+15 −0
Original line number Diff line number Diff line
@@ -3783,6 +3783,19 @@ static const struct bpf_func_proto sk_skb_change_head_proto = { 
	.arg2_type	= ARG_ANYTHING,

	.arg3_type	= ARG_ANYTHING,

};



BPF_CALL_1(bpf_xdp_get_buff_len, struct  xdp_buff*, xdp)

{

	return xdp_get_buff_len(xdp);

}



static const struct bpf_func_proto bpf_xdp_get_buff_len_proto = {

	.func		= bpf_xdp_get_buff_len,

	.gpl_only	= false,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_CTX,

};



static unsigned long xdp_get_metalen(const struct xdp_buff *xdp)

{

	return xdp_data_meta_unsupported(xdp) ? 0 :
@@ -7533,6 +7546,8 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		return &bpf_xdp_redirect_map_proto;

	case BPF_FUNC_xdp_adjust_tail:

		return &bpf_xdp_adjust_tail_proto;

	case BPF_FUNC_xdp_get_buff_len:

		return &bpf_xdp_get_buff_len_proto;

	case BPF_FUNC_fib_lookup:

		return &bpf_xdp_fib_lookup_proto;

	case BPF_FUNC_check_mtu:

tools/include/uapi/linux/bpf.h

+7 −0
Original line number Diff line number Diff line
@@ -5054,6 +5054,12 @@ union bpf_attr { 
 *		This helper is currently supported by cgroup programs only.

 *	Return

 *		0 on success, or a negative error in case of failure.

 *

 * u64 bpf_xdp_get_buff_len(struct xdp_buff *xdp_md)

 *	Description

 *		Get the total size of a given xdp buff (linear and paged area)

 *	Return

 *		The total size of a given xdp buffer.

 */

#define __BPF_FUNC_MAPPER(FN)		\

	FN(unspec),			\
@@ -5244,6 +5250,7 @@ union bpf_attr { 
	FN(get_func_arg_cnt),		\

	FN(get_retval),			\

	FN(set_retval),			\

	FN(xdp_get_buff_len),		\

	/* */



/* integer value in 'imm' field of BPF_CALL instruction selects which helper