[PATCH v4 bpf-next 11/15] libbpf: Add egress XDP support

[David Ahern <dsahern@kernel.org>]

From: David Ahern <dahern@digitalocean.com>

New section name hint, xdp_egress, is added to set expected attach
type at program load. Programs can use xdp_egress as the prefix in
the SEC statement to load the program with the BPF_XDP_EGRESS
attach type set.

egress_prog_id is added to xdp_link_info to report the program
id.

Signed-off-by: David Ahern <dahern@digitalocean.com>
---
 tools/lib/bpf/libbpf.c  | 2 ++
 tools/lib/bpf/libbpf.h  | 1 +
 tools/lib/bpf/netlink.c | 6 ++++++
 3 files changed, 9 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8e1dc6980fac..60c9c503e1c6 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -6366,6 +6366,8 @@ static const struct bpf_sec_def section_defs[] = {
 		.is_attach_btf = true,
 		.expected_attach_type = BPF_LSM_MAC,
 		.attach_fn = attach_lsm),
+	BPF_EAPROG_SEC("xdp_egress",		BPF_PROG_TYPE_XDP,
+						BPF_XDP_EGRESS),
 	BPF_PROG_SEC("xdp",			BPF_PROG_TYPE_XDP),
 	BPF_PROG_SEC("perf_event",		BPF_PROG_TYPE_PERF_EVENT),
 	BPF_PROG_SEC("lwt_in",			BPF_PROG_TYPE_LWT_IN),
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index f1dacecb1619..445c3789faa4 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -454,6 +454,7 @@ struct xdp_link_info {
 	__u32 hw_prog_id;
 	__u32 skb_prog_id;
 	__u8 attach_mode;
+	__u32 egress_prog_id;
 };
 
 struct bpf_xdp_set_link_opts {
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 312f887570b2..da0b383dbd5d 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -280,6 +280,10 @@ static int get_xdp_info(void *cookie, void *msg, struct nlattr **tb)
 		xdp_id->info.hw_prog_id = libbpf_nla_getattr_u32(
 			xdp_tb[IFLA_XDP_HW_PROG_ID]);
 
+	if (xdp_tb[IFLA_XDP_EGRESS_PROG_ID])
+		xdp_id->info.egress_prog_id = libbpf_nla_getattr_u32(
+			xdp_tb[IFLA_XDP_EGRESS_PROG_ID]);
+
 	return 0;
 }
 
@@ -331,6 +335,8 @@ static __u32 get_xdp_id(struct xdp_link_info *info, __u32 flags)
 		return info->hw_prog_id;
 	if (flags & XDP_FLAGS_SKB_MODE)
 		return info->skb_prog_id;
+	if (flags & XDP_FLAGS_EGRESS_MODE)
+		return info->egress_prog_id;
 
 	return 0;
 }
-- 
2.21.1 (Apple Git-122.3)