Subject: [PATCH v2 bpf-next 17/17] samples/bpf: add XDP egress support to xdp1

From: David Ahern <[email-masked]>
Date: Thu, 23 Apr 2020 20:11:48 -0600

From: David Ahern <[email-masked]>

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

Signed-off-by: Prashant Bhole <[email-masked]>
Signed-off-by: David Ahern <[email-masked]>
---
 samples/bpf/xdp1_user.c | 39 ++++++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c
index c447ad9e3a1d..9f79bd537763 100644
--- a/samples/bpf/xdp1_user.c
+++ b/samples/bpf/xdp1_user.c
@@ -20,22 +20,37 @@
 
 static int ifindex;
 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
+static struct bpf_xdp_set_link_opts opts;
 static __u32 prog_id;
 
 static void int_exit(int sig)
 {
 	__u32 curr_prog_id = 0;
+	int rc;
 
-	if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
-		printf("bpf_get_link_xdp_id failed\n");
+	if (opts.egress)
+		rc = bpf_get_link_xdp_egress_id(ifindex, &curr_prog_id, xdp_flags);
+	else
+		rc = bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags);
+
+	if (rc) {
+		printf("Failed to get existing prog id for device");
 		exit(1);
 	}
+
+	if (curr_prog_id)
+		opts.old_fd = bpf_prog_get_fd_by_id(curr_prog_id);
+
 	if (prog_id == curr_prog_id)
-		bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+		bpf_set_link_xdp_fd_opts(ifindex, -1, xdp_flags, &opts);
 	else if (!curr_prog_id)
 		printf("couldn't find a prog id on a given interface\n");
 	else
 		printf("program on interface changed, not removing\n");
+
+	if (opts.old_fd >= 0)
+		close(opts.old_fd);
+
 	exit(0);
 }
 
@@ -73,7 +88,8 @@ 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);
 }
 
@@ -83,15 +99,20 @@ int main(int argc, char **argv)
 	struct bpf_prog_load_attr prog_load_attr = {
 		.prog_type	= BPF_PROG_TYPE_XDP,
 	};
+	struct bpf_xdp_set_link_opts opts;
 	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;
 	char filename[256];
 	int err;
 
+	memset(&opts, 0, sizeof(opts));
+	opts.sz = sizeof(opts);
+	opts.old_fd = -1;
+
 	while ((opt = getopt(argc, argv, optstr)) != -1) {
 		switch (opt) {
 		case 'S':
@@ -103,13 +124,17 @@ int main(int argc, char **argv)
 		case 'F':
 			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
 			break;
+		case 'E':
+			opts.egress = true;
+			prog_load_attr.expected_attach_type = BPF_XDP_EGRESS;
+			break;
 		default:
 			usage(basename(argv[0]));
 			return 1;
 		}
 	}
 
-	if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
+	if (!(xdp_flags & XDP_FLAGS_SKB_MODE) && !opts.egress)
 		xdp_flags |= XDP_FLAGS_DRV_MODE;
 
 	if (optind == argc) {
@@ -149,7 +174,7 @@ 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 (bpf_set_link_xdp_fd_opts(ifindex, prog_fd, xdp_flags, &opts) < 0) {
 		printf("link set xdp fd failed\n");
 		return 1;
 	}
-- 
2.21.1 (Apple Git-122.3)