Subject: [PATCH RFC v4 bpf-next 11/11] samples/bpf: xdp1, add egress XDP support

From: David Ahern <[email-masked]>
Date: Wed, 26 Feb 2020 20:20:13 -0700

From: Prashant Bhole <[email-masked]>

xdp1 and xdp2 now accept -E flag to set XDP program in the egress
path.

Signed-off-by: Prashant Bhole <[email-masked]>
---
 samples/bpf/xdp1_user.c | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c
index c447ad9e3a1d..72c5bedbd030 100644
--- a/samples/bpf/xdp1_user.c
+++ b/samples/bpf/xdp1_user.c
@@ -21,17 +21,27 @@
 static int ifindex;
 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 static __u32 prog_id;
+static bool egress;
 
 static void int_exit(int sig)
 {
 	__u32 curr_prog_id = 0;
+	int err;
 
-	if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
+	if (egress)
+		err = bpf_get_link_xdp_egress_id(ifindex, &curr_prog_id,
+						 xdp_flags);
+	else
+		err = bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags);
+	if (err) {
 		printf("bpf_get_link_xdp_id failed\n");
 		exit(1);
 	}
 	if (prog_id == curr_prog_id)
-		bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+		if (egress)
+			bpf_set_link_xdp_egress_fd(ifindex, -1, xdp_flags);
+		else
+			bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
 	else if (!curr_prog_id)
 		printf("couldn't find a prog id on a given interface\n");
 	else
@@ -73,7 +83,8 @@ static void usage(const char *prog)
 		"OPTS:\n"
 		"    -S    use skb-mode\n"
 		"    -N    enforce native mode\n"
-		"    -F    force loading prog\n",
+		"    -F    force loading prog\n"
+		"    -E	   egress path program\n",
 		prog);
 }
 
@@ -85,7 +96,7 @@ int main(int argc, char **argv)
 	};
 	struct bpf_prog_info info = {};
 	__u32 info_len = sizeof(info);
-	const char *optstr = "FSN";
+	const char *optstr = "FSNE";
 	int prog_fd, map_fd, opt;
 	struct bpf_object *obj;
 	struct bpf_map *map;
@@ -103,6 +114,9 @@ int main(int argc, char **argv)
 		case 'F':
 			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
 			break;
+		case 'E':
+			egress = true;
+			break;
 		default:
 			usage(basename(argv[0]));
 			return 1;
@@ -130,6 +144,8 @@ int main(int argc, char **argv)
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 	prog_load_attr.file = filename;
+	if (egress)
+		prog_load_attr.expected_attach_type = BPF_XDP_EGRESS;
 
 	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 		return 1;
@@ -149,7 +165,11 @@ int main(int argc, char **argv)
 	signal(SIGINT, int_exit);
 	signal(SIGTERM, int_exit);
 
-	if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
+	if (egress)
+		err = bpf_set_link_xdp_egress_fd(ifindex, prog_fd, xdp_flags);
+	else
+		err = bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags);
+	if (err < 0) {
 		printf("link set xdp fd failed\n");
 		return 1;
 	}
-- 
2.21.1 (Apple Git-122.3)