samples/bpf: Extend RLIMIT_MEMLOCK for xdp_{sample_pkts, router_ipv4}

There is a common problem with xdp samples that happens when user wants
to run a particular sample and some bpf program is already loaded. The
default 64kb RLIMIT_MEMLOCK resource limit will cause a following error
(assuming that xdp sample that is failing was converted to libbpf
usage):

libbpf: Error in bpf_object__probe_name():Operation not permitted(1).
Couldn't load basic 'r0 = 0' BPF program.
libbpf: failed to load object './xdp_sample_pkts_kern.o'

Fix it in xdp_sample_pkts and xdp_router_ipv4 by setting RLIMIT_MEMLOCK
to RLIM_INFINITY.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

samples/bpf/xdp_router_ipv4_user.c

@@ -25,6 +25,7 @@
 #include <sys/syscall.h>
 #include "bpf_util.h"
 #include "bpf/libbpf.h"
+#include <sys/resource.h>
 
 int sock, sock_arp, flags = 0;
 static int total_ifindex;
@@ -609,6 +610,7 @@ static int monitor_route(void)
 
 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,
 	};
@@ -635,6 +637,11 @@ int main(int ac, char **argv)
 		ifname_list = (argv + 1);
 	}
 
+	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+		perror("setrlimit(RLIMIT_MEMLOCK)");
+		return 1;
+	}
+
 	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
 		return 1;
 

samples/bpf/xdp_sample_pkts_user.c

@@ -12,6 +12,7 @@
 #include <signal.h>
 #include <libbpf.h>
 #include <bpf/bpf.h>
+#include <sys/resource.h>
 
 #include "perf-sys.h"
 #include "trace_helpers.h"
@@ -99,6 +100,7 @@ static void sig_handler(int signo)
 
 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,
 	};
@@ -114,6 +116,11 @@ int main(int argc, char **argv)
 		return 1;
 	}
 
+	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+		perror("setrlimit(RLIMIT_MEMLOCK)");
+		return 1;
+	}
+
 	numcpus = get_nprocs();
 	if (numcpus > MAX_CPUS)
 		numcpus = MAX_CPUS;