netdev - [PATCH RFC-v5 bpf-next 12/12] samples/bpf: add XDP egress support to xdp1

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Date:   Mon, 13 Apr 2020 11:18:01 -0600
From:   David Ahern <dsahern@...nel.org>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org,
        prashantbhole.linux@...il.com, jasowang@...hat.com,
        brouer@...hat.com, toke@...hat.com, toshiaki.makita1@...il.com,
        daniel@...earbox.net, john.fastabend@...il.com, ast@...nel.org,
        kafai@...com, songliubraving@...com, yhs@...com, andriin@...com,
        dsahern@...il.com, David Ahern <dahern@...italocean.com>
Subject: [PATCH RFC-v5 bpf-next 12/12] samples/bpf: add XDP egress support to xdp1

From: David Ahern <dahern@...italocean.com>

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

Signed-off-by: Prashant Bhole <prashantbhole.linux@...il.com>
Signed-off-by: David Ahern <dahern@...italocean.com>
---
 samples/bpf/xdp1_user.c | 38 +++++++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c
index c447ad9e3a1d..1e74020203ca 100644
--- a/samples/bpf/xdp1_user.c
+++ b/samples/bpf/xdp1_user.c
@@ -21,18 +21,32 @@
 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)
 {
+	struct bpf_xdp_set_link_opts opts = { .sz = sizeof(opts) };
 	__u32 curr_prog_id = 0;
+	int err, old_fd;
 
-	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);
-	else if (!curr_prog_id)
+	if (prog_id == curr_prog_id) {
+		if (egress)
+			opts.egress = 1;
+
+		old_fd = bpf_prog_get_fd_by_id(prog_id);
+		opts.old_fd = old_fd;
+		bpf_set_link_xdp_fd_opts(ifindex, -1, xdp_flags, &opts);
+		close(old_fd);
+	} 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");
@@ -73,19 +87,21 @@ 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);
 }
 
 int main(int argc, char **argv)
 {
+	struct bpf_xdp_set_link_opts opts = { .sz = sizeof(opts) };
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	struct bpf_prog_load_attr prog_load_attr = {
 		.prog_type	= BPF_PROG_TYPE_XDP,
 	};
 	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 +119,9 @@ 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 +149,10 @@ int main(int argc, char **argv)
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 	prog_load_attr.file = filename;
+	if (egress) {
+		opts.egress = 1;
+		prog_load_attr.expected_attach_type = BPF_XDP_EGRESS;
+	}
 
 	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 		return 1;
@@ -149,7 +172,8 @@ 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) {
+	err = bpf_set_link_xdp_fd_opts(ifindex, prog_fd, xdp_flags, &opts);
+	if (err < 0) {
 		printf("link set xdp fd failed\n");
 		return 1;
 	}
-- 
2.21.1 (Apple Git-122.3)