[PATCH v9 bpf-next 09/14] bpf: introduce bpf_xdp_get_buff_len helper
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From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: 2021-06-14 12:51:29
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Revision v9 of 20 in this series.
Revisions (20)
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Introduce bpf_xdp_get_buff_len helper in order to return the xdp buffer total size (linear and paged area) Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> --- include/uapi/linux/bpf.h | 7 +++++++ net/core/filter.c | 23 +++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 7 +++++++ 3 files changed, 37 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 2c1ba70abbf1..0116c0c569fe 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -4778,6 +4778,12 @@ union bpf_attr { * Execute close syscall for given FD. * Return * A syscall result. + * + * int 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), \
@@ -4949,6 +4955,7 @@ union bpf_attr { FN(sys_bpf), \ FN(btf_find_by_name_kind), \ FN(sys_close), \ + FN(xdp_get_buff_len), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/net/core/filter.c b/net/core/filter.c
index 05f574a3d690..b0855f2d4726 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -3918,6 +3918,27 @@ static int bpf_xdp_mb_adjust_tail(struct xdp_buff *xdp, int offset) return 0; } +BPF_CALL_1(bpf_xdp_get_buff_len, struct xdp_buff*, xdp) +{ + int data_len = 0; + + if (unlikely(xdp_buff_is_mb(xdp))) { + struct skb_shared_info *sinfo; + + sinfo = xdp_get_shared_info_from_buff(xdp); + data_len = sinfo->data_len; + } + + return (xdp->data_end - xdp->data) + data_len; +} + +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, +}; + BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset) { void *data_hard_end = xdp_data_hard_end(xdp); /* use xdp->frame_sz */
@@ -7454,6 +7475,8 @@ 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:
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 2c1ba70abbf1..0116c0c569fe 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h@@ -4778,6 +4778,12 @@ union bpf_attr { * Execute close syscall for given FD. * Return * A syscall result. + * + * int 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), \
@@ -4949,6 +4955,7 @@ union bpf_attr { FN(sys_bpf), \ FN(btf_find_by_name_kind), \ FN(sys_close), \ + FN(xdp_get_buff_len), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper
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2.31.1