tools/bpf: fix test_sock and test_sock_addr.sh failure

The bpf selftests test_sock and test_sock_addr.sh failed
in my test machine. The failure looks like:
$ ./test_sock
Test case: bind4 load with invalid access: src_ip6 .. [PASS]
Test case: bind4 load with invalid access: mark .. [PASS]
Test case: bind6 load with invalid access: src_ip4 .. [PASS]
Test case: sock_create load with invalid access: src_port .. [PASS]
Test case: sock_create load w/o expected_attach_type (compat mode) .. [FAIL]
Test case: sock_create load w/ expected_attach_type .. [FAIL]
Test case: attach type mismatch bind4 vs bind6 .. [FAIL]
...
Summary: 4 PASSED, 12 FAILED
$ ./test_sock_addr.sh
Wait for testing IPv4/IPv6 to become available .....
ERROR: Timeout waiting for test IP to become available.

In test_sock, bpf program loads failed due to hitting memlock limits.
In test_sock_addr.sh, my test machine is a ipv6 only test box and using
"ping" without specifying address family for an ipv6 address does not work.

This patch fixed the issue by including header bpf_rlimit.h in test_sock.c
and test_sock_addr.c, and specifying address family for ping command.

Cc: Andrey Ignatov <[e-mail]>
Signed-off-by: Yonghong Song <[e-mail]>
Acked-by: Andrey Ignatov <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>

tools/testing/selftests/bpf/test_sock.c

···
 #include <bpf/bpf.h>
 
 #include "cgroup_helpers.h"
+#include "bpf_rlimit.h"
 
 #ifndef ARRAY_SIZE
 # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

tools/testing/selftests/bpf/test_sock_addr.c

···
 #include <bpf/libbpf.h>
 
 #include "cgroup_helpers.h"
+#include "bpf_rlimit.h"
 
 #define CG_PATH	"/foo"
 #define CONNECT4_PROG_PATH	"./connect4_prog.o"

tools/testing/selftests/bpf/test_sock_addr.sh

···
 
 ping_once()
 {
-	ping -q -c 1 -W 1 ${1%%/*} >/dev/null 2>&1
+	ping -${1} -q -c 1 -W 1 ${2%%/*} >/dev/null 2>&1
 }
 
 wait_for_ip()
···
 	echo -n "Wait for testing IPv4/IPv6 to become available "
 	for _i in $(seq ${MAX_PING_TRIES}); do
 		echo -n "."
-		if ping_once ${TEST_IPv4} && ping_once ${TEST_IPv6}; then
+		if ping_once 4 ${TEST_IPv4} && ping_once 6 ${TEST_IPv6}; then
 			echo " OK"
 			return
 		fi