samples/bpf: Add a "force" flag to XDP samples

Make xdp samples consistent with iproute2 behavior and set the
XDP_FLAGS_UPDATE_IF_NOEXIST by default when setting the xdp program on
interface. Provide an option for user to force the program loading,
which as a result will not include the mentioned flag in
bpf_set_link_xdp_fd call.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

samples/bpf/xdp1_user.c

@@ -22,7 +22,7 @@
 #include "bpf/libbpf.h"
 
 static int ifindex;
-static __u32 xdp_flags;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 
 static void int_exit(int sig)
 {
@@ -63,7 +63,8 @@ static void usage(const char *prog)
 		"usage: %s [OPTS] IFACE\n\n"
 		"OPTS:\n"
 		"    -S    use skb-mode\n"
-		"    -N    enforce native mode\n",
+		"    -N    enforce native mode\n"
+		"    -F    force loading prog\n",
 		prog);
 }
 
@@ -73,7 +74,7 @@ int main(int argc, char **argv)
 	struct bpf_prog_load_attr prog_load_attr = {
 		.prog_type	= BPF_PROG_TYPE_XDP,
 	};
-	const char *optstr = "SN";
+	const char *optstr = "FSN";
 	int prog_fd, map_fd, opt;
 	struct bpf_object *obj;
 	struct bpf_map *map;
@@ -87,6 +88,9 @@ int main(int argc, char **argv)
 		case 'N':
 			xdp_flags |= XDP_FLAGS_DRV_MODE;
 			break;
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		default:
 			usage(basename(argv[0]));
 			return 1;

samples/bpf/xdp_adjust_tail_user.c

@@ -24,7 +24,7 @@
 #define STATS_INTERVAL_S 2U
 
 static int ifindex = -1;
-static __u32 xdp_flags;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 
 static void int_exit(int sig)
 {
@@ -60,6 +60,7 @@ static void usage(const char *cmd)
 	printf("    -T <stop-after-X-seconds> Default: 0 (forever)\n");
 	printf("    -S use skb-mode\n");
 	printf("    -N enforce native mode\n");
+	printf("    -F force loading prog\n");
 	printf("    -h Display this help\n");
 }
 
@@ -70,8 +71,8 @@ int main(int argc, char **argv)
 		.prog_type	= BPF_PROG_TYPE_XDP,
 	};
 	unsigned char opt_flags[256] = {};
+	const char *optstr = "i:T:SNFh";
 	unsigned int kill_after_s = 0;
-	const char *optstr = "i:T:SNh";
 	int i, prog_fd, map_fd, opt;
 	struct bpf_object *obj;
 	struct bpf_map *map;
@@ -96,6 +97,9 @@ int main(int argc, char **argv)
 		case 'N':
 			xdp_flags |= XDP_FLAGS_DRV_MODE;
 			break;
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		default:
 			usage(argv[0]);
 			return 1;

samples/bpf/xdp_redirect_cpu_user.c

@@ -33,7 +33,7 @@ static int ifindex = -1;
 static char ifname_buf[IF_NAMESIZE];
 static char *ifname;
 
-static __u32 xdp_flags;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 static int cpu_map_fd;
 static int rx_cnt_map_fd;
 static int redirect_err_cnt_map_fd;
@@ -62,6 +62,7 @@ static const struct option long_options[] = {
 	{"cpu",		required_argument,	NULL, 'c' },
 	{"stress-mode", no_argument,		NULL, 'x' },
 	{"no-separators", no_argument,		NULL, 'z' },
+	{"force",	no_argument,		NULL, 'F' },
 	{0, 0, NULL,  0 }
 };
 
@@ -651,7 +652,7 @@ int main(int argc, char **argv)
 	mark_cpus_unavailable();
 
 	/* Parse commands line args */
-	while ((opt = getopt_long(argc, argv, "hSd:",
+	while ((opt = getopt_long(argc, argv, "hSd:s:p:q:c:xzF",
 				  long_options, &longindex)) != -1) {
 		switch (opt) {
 		case 'd':
@@ -700,6 +701,9 @@ int main(int argc, char **argv)
 		case 'q':
 			qsize = atoi(optarg);
 			break;
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		case 'h':
 		error:
 		default:

samples/bpf/xdp_redirect_map_user.c

@@ -30,7 +30,7 @@ static int ifindex_in;
 static int ifindex_out;
 static bool ifindex_out_xdp_dummy_attached = true;
 
-static __u32 xdp_flags;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 static int rxcnt_map_fd;
 
 static void int_exit(int sig)
@@ -70,7 +70,8 @@ static void usage(const char *prog)
 		"usage: %s [OPTS] IFINDEX_IN IFINDEX_OUT\n\n"
 		"OPTS:\n"
 		"    -S    use skb-mode\n"
-		"    -N    enforce native mode\n",
+		"    -N    enforce native mode\n"
+		"    -F    force loading prog\n",
 		prog);
 }
 
@@ -82,7 +83,7 @@ int main(int argc, char **argv)
 	};
 	struct bpf_program *prog, *dummy_prog;
 	int prog_fd, dummy_prog_fd;
-	const char *optstr = "SN";
+	const char *optstr = "FSN";
 	struct bpf_object *obj;
 	int ret, opt, key = 0;
 	char filename[256];
@@ -96,6 +97,9 @@ int main(int argc, char **argv)
 		case 'N':
 			xdp_flags |= XDP_FLAGS_DRV_MODE;
 			break;
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		default:
 			usage(basename(argv[0]));
 			return 1;

samples/bpf/xdp_redirect_user.c

@@ -30,7 +30,7 @@ static int ifindex_in;
 static int ifindex_out;
 static bool ifindex_out_xdp_dummy_attached = true;
 
-static __u32 xdp_flags;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 static int rxcnt_map_fd;
 
 static void int_exit(int sig)
@@ -70,7 +70,8 @@ static void usage(const char *prog)
 		"usage: %s [OPTS] IFINDEX_IN IFINDEX_OUT\n\n"
 		"OPTS:\n"
 		"    -S    use skb-mode\n"
-		"    -N    enforce native mode\n",
+		"    -N    enforce native mode\n"
+		"    -F    force loading prog\n",
 		prog);
 }
 
@@ -83,7 +84,7 @@ int main(int argc, char **argv)
 	};
 	struct bpf_program *prog, *dummy_prog;
 	int prog_fd, tx_port_map_fd, opt;
-	const char *optstr = "SN";
+	const char *optstr = "FSN";
 	struct bpf_object *obj;
 	char filename[256];
 	int dummy_prog_fd;
@@ -97,6 +98,9 @@ int main(int argc, char **argv)
 		case 'N':
 			xdp_flags |= XDP_FLAGS_DRV_MODE;
 			break;
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		default:
 			usage(basename(argv[0]));
 			return 1;

samples/bpf/xdp_router_ipv4_user.c

@@ -26,8 +26,9 @@
 #include "bpf_util.h"
 #include "bpf/libbpf.h"
 #include <sys/resource.h>
+#include <libgen.h>
 
-int sock, sock_arp, flags = 0;
+int sock, sock_arp, flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 static int total_ifindex;
 int *ifindex_list;
 char buf[8192];
@@ -608,33 +609,56 @@ cleanup:
 	return ret;
 }
 
+static void usage(const char *prog)
+{
+	fprintf(stderr,
+		"%s: %s [OPTS] interface name list\n\n"
+		"OPTS:\n"
+		"    -S    use skb-mode\n"
+		"    -F    force loading prog\n",
+		__func__, prog);
+}
+
 int main(int ac, char **argv)
 {
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	struct bpf_prog_load_attr prog_load_attr = {
 		.prog_type	= BPF_PROG_TYPE_XDP,
 	};
+	const char *optstr = "SF";
 	struct bpf_object *obj;
 	char filename[256];
 	char **ifname_list;
-	int prog_fd;
+	int prog_fd, opt;
 	int i = 1;
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 	prog_load_attr.file = filename;
 
-	if (ac < 2) {
-		printf("usage: %s [-S] Interface name list\n", argv[0]);
-		return 1;
+	total_ifindex = ac - 1;
+	ifname_list = (argv + 1);
+
+	while ((opt = getopt(ac, argv, optstr)) != -1) {
+		switch (opt) {
+		case 'S':
+			flags |= XDP_FLAGS_SKB_MODE;
+			total_ifindex--;
+			ifname_list++;
+			break;
+		case 'F':
+			flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			total_ifindex--;
+			ifname_list++;
+			break;
+		default:
+			usage(basename(argv[0]));
+			return 1;
+		}
 	}
-	if (!strcmp(argv[1], "-S")) {
-		flags = XDP_FLAGS_SKB_MODE;
-		total_ifindex = ac - 2;
-		ifname_list = (argv + 2);
-	} else {
-		flags = 0;
-		total_ifindex = ac - 1;
-		ifname_list = (argv + 1);
+
+	if (optind == ac) {
+		usage(basename(argv[0]));
+		return 1;
 	}
 
 	if (setrlimit(RLIMIT_MEMLOCK, &r)) {

samples/bpf/xdp_rxq_info_user.c

@@ -30,7 +30,7 @@ static int ifindex = -1;
 static char ifname_buf[IF_NAMESIZE];
 static char *ifname;
 
-static __u32 xdp_flags;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 
 static struct bpf_map *stats_global_map;
 static struct bpf_map *rx_queue_index_map;
@@ -52,6 +52,7 @@ static const struct option long_options[] = {
 	{"action",	required_argument,	NULL, 'a' },
 	{"readmem", 	no_argument,		NULL, 'r' },
 	{"swapmac", 	no_argument,		NULL, 'm' },
+	{"force",	no_argument,		NULL, 'F' },
 	{0, 0, NULL,  0 }
 };
 
@@ -487,7 +488,7 @@ int main(int argc, char **argv)
 	}
 
 	/* Parse commands line args */
-	while ((opt = getopt_long(argc, argv, "hSd:",
+	while ((opt = getopt_long(argc, argv, "FhSrmzd:s:a:",
 				  long_options, &longindex)) != -1) {
 		switch (opt) {
 		case 'd':
@@ -524,6 +525,9 @@ int main(int argc, char **argv)
 		case 'm':
 			cfg_options |= SWAP_MAC;
 			break;
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		case 'h':
 		error:
 		default:

samples/bpf/xdp_sample_pkts_user.c

@@ -13,6 +13,8 @@
 #include <libbpf.h>
 #include <bpf/bpf.h>
 #include <sys/resource.h>
+#include <libgen.h>
+#include <linux/if_link.h>
 
 #include "perf-sys.h"
 #include "trace_helpers.h"
@@ -21,12 +23,13 @@
 static int pmu_fds[MAX_CPUS], if_idx;
 static struct perf_event_mmap_page *headers[MAX_CPUS];
 static char *if_name;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 
 static int do_attach(int idx, int fd, const char *name)
 {
 	int err;
 
-	err = bpf_set_link_xdp_fd(idx, fd, 0);
+	err = bpf_set_link_xdp_fd(idx, fd, xdp_flags);
 	if (err < 0)
 		printf("ERROR: failed to attach program to %s\n", name);
 
@@ -98,21 +101,42 @@ static void sig_handler(int signo)
 	exit(0);
 }
 
+static void usage(const char *prog)
+{
+	fprintf(stderr,
+		"%s: %s [OPTS] <ifname|ifindex>\n\n"
+		"OPTS:\n"
+		"    -F    force loading prog\n",
+		__func__, prog);
+}
+
 int main(int argc, char **argv)
 {
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	struct bpf_prog_load_attr prog_load_attr = {
 		.prog_type	= BPF_PROG_TYPE_XDP,
 	};
+	const char *optstr = "F";
+	int prog_fd, map_fd, opt;
 	struct bpf_object *obj;
 	struct bpf_map *map;
-	int prog_fd, map_fd;
 	char filename[256];
 	int ret, err, i;
 	int numcpus;
 
-	if (argc < 2) {
-		printf("Usage: %s <ifname>\n", argv[0]);
+	while ((opt = getopt(argc, argv, optstr)) != -1) {
+		switch (opt) {
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
+		default:
+			usage(basename(argv[0]));
+			return 1;
+		}
+	}
+
+	if (optind == argc) {
+		usage(basename(argv[0]));
 		return 1;
 	}
 
@@ -143,16 +167,16 @@ int main(int argc, char **argv)
 	}
 	map_fd = bpf_map__fd(map);
 
-	if_idx = if_nametoindex(argv[1]);
+	if_idx = if_nametoindex(argv[optind]);
 	if (!if_idx)
-		if_idx = strtoul(argv[1], NULL, 0);
+		if_idx = strtoul(argv[optind], NULL, 0);
 
 	if (!if_idx) {
 		fprintf(stderr, "Invalid ifname\n");
 		return 1;
 	}
-	if_name = argv[1];
-	err = do_attach(if_idx, prog_fd, argv[1]);
+	if_name = argv[optind];
+	err = do_attach(if_idx, prog_fd, if_name);
 	if (err)
 		return err;
 

samples/bpf/xdp_tx_iptunnel_user.c

@@ -25,7 +25,7 @@
 #define STATS_INTERVAL_S 2U
 
 static int ifindex = -1;
-static __u32 xdp_flags = 0;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 static int rxcnt_map_fd;
 
 static void int_exit(int sig)
@@ -83,6 +83,7 @@ static void usage(const char *cmd)
 	printf("    -P <IP-Protocol> Default is TCP\n");
 	printf("    -S use skb-mode\n");
 	printf("    -N enforce native mode\n");
+	printf("    -F Force loading the XDP prog\n");
 	printf("    -h Display this help\n");
 }
 
@@ -145,7 +146,7 @@ int main(int argc, char **argv)
 	};
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	int min_port = 0, max_port = 0, vip2tnl_map_fd;
-	const char *optstr = "i:a:p:s:d:m:T:P:SNh";
+	const char *optstr = "i:a:p:s:d:m:T:P:FSNh";
 	unsigned char opt_flags[256] = {};
 	unsigned int kill_after_s = 0;
 	struct iptnl_info tnl = {};
@@ -217,6 +218,9 @@ int main(int argc, char **argv)
 		case 'N':
 			xdp_flags |= XDP_FLAGS_DRV_MODE;
 			break;
+		case 'F':
+			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		default:
 			usage(argv[0]);
 			return 1;

samples/bpf/xdpsock_user.c

@@ -68,7 +68,7 @@ enum benchmark_type {
 };
 
 static enum benchmark_type opt_bench = BENCH_RXDROP;
-static u32 opt_xdp_flags;
+static u32 opt_xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 static const char *opt_if = "";
 static int opt_ifindex;
 static int opt_queue;
@@ -682,7 +682,7 @@ static void parse_command_line(int argc, char **argv)
 	opterr = 0;
 
 	for (;;) {
-		c = getopt_long(argc, argv, "rtli:q:psSNn:cz", long_options,
+		c = getopt_long(argc, argv, "Frtli:q:psSNn:cz", long_options,
 				&option_index);
 		if (c == -1)
 			break;
@@ -725,6 +725,9 @@ static void parse_command_line(int argc, char **argv)
 		case 'c':
 			opt_xdp_bind_flags |= XDP_COPY;
 			break;
+		case 'F':
+			opt_xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			break;
 		default:
 			usage(basename(argv[0]));
 		}