kselftests/bpf: use ping6 as the default ipv6 ping binary if it exists

ping binary on some distros doesn't support "ping -6" anymore.

Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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 <rdna@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

selftests/bpf: Selftest for sys_connect hooks

Add selftest for BPF_CGROUP_INET4_CONNECT and BPF_CGROUP_INET6_CONNECT
attach types.

Try to connect(2) to specified IP:port and test that:
* remote IP:port pair is overridden;
* local end of connection is bound to specified IP.

All combinations of IPv4/IPv6 and TCP/UDP are tested.

Example:
# tcpdump -pn -i lo -w connect.pcap 2>/dev/null &
[1] 478
# strace -qqf -e connect -o connect.trace ./test_sock_addr.sh
Wait for testing IPv4/IPv6 to become available ... OK
Load bind4 with invalid type (can pollute stderr) ... REJECTED
Load bind4 with valid type ... OK
Attach bind4 with invalid type ... REJECTED
Attach bind4 with valid type ... OK
Load connect4 with invalid type (can pollute stderr) libbpf: load bpf \
program failed: Permission denied
libbpf: -- BEGIN DUMP LOG ---
libbpf:
0: (b7) r2 = 23569
1: (63) *(u32 *)(r1 +24) = r2
2: (b7) r2 = 16777343
3: (63) *(u32 *)(r1 +4) = r2
invalid bpf_context access off=4 size=4
[ 1518.404609] random: crng init done

libbpf: -- END LOG --
libbpf: failed to load program 'cgroup/connect4'
libbpf: failed to load object './connect4_prog.o'
... REJECTED
Load connect4 with valid type ... OK
Attach connect4 with invalid type ... REJECTED
Attach connect4 with valid type ... OK
Test case #1 (IPv4/TCP):
Requested: bind(192.168.1.254, 4040) ..
Actual: bind(127.0.0.1, 4444)
Requested: connect(192.168.1.254, 4040) from (*, *) ..
Actual: connect(127.0.0.1, 4444) from (127.0.0.4, 56068)
Test case #2 (IPv4/UDP):
Requested: bind(192.168.1.254, 4040) ..
Actual: bind(127.0.0.1, 4444)
Requested: connect(192.168.1.254, 4040) from (*, *) ..
Actual: connect(127.0.0.1, 4444) from (127.0.0.4, 56447)
Load bind6 with invalid type (can pollute stderr) ... REJECTED
Load bind6 with valid type ... OK
Attach bind6 with invalid type ... REJECTED
Attach bind6 with valid type ... OK
Load connect6 with invalid type (can pollute stderr) libbpf: load bpf \
program failed: Permission denied
libbpf: -- BEGIN DUMP LOG ---
libbpf:
0: (b7) r6 = 0
1: (63) *(u32 *)(r1 +12) = r6
invalid bpf_context access off=12 size=4

libbpf: -- END LOG --
libbpf: failed to load program 'cgroup/connect6'
libbpf: failed to load object './connect6_prog.o'
... REJECTED
Load connect6 with valid type ... OK
Attach connect6 with invalid type ... REJECTED
Attach connect6 with valid type ... OK
Test case #3 (IPv6/TCP):
Requested: bind(face:b00c:1234:5678::abcd, 6060) ..
Actual: bind(::1, 6666)
Requested: connect(face:b00c:1234:5678::abcd, 6060) from (*, *)
Actual: connect(::1, 6666) from (::6, 37458)
Test case #4 (IPv6/UDP):
Requested: bind(face:b00c:1234:5678::abcd, 6060) ..
Actual: bind(::1, 6666)
Requested: connect(face:b00c:1234:5678::abcd, 6060) from (*, *)
Actual: connect(::1, 6666) from (::6, 39315)
### SUCCESS
# egrep 'connect\(.*AF_INET' connect.trace | \
> egrep -vw 'htons\(1025\)' | fold -b -s -w 72
502 connect(7, {sa_family=AF_INET, sin_port=htons(4040),
sin_addr=inet_addr("192.168.1.254")}, 128) = 0
502 connect(8, {sa_family=AF_INET, sin_port=htons(4040),
sin_addr=inet_addr("192.168.1.254")}, 128) = 0
502 connect(9, {sa_family=AF_INET6, sin6_port=htons(6060),
inet_pton(AF_INET6, "face:b00c:1234:5678::abcd", &sin6_addr),
sin6_flowinfo=0, sin6_scope_id=0}, 128) = 0
502 connect(10, {sa_family=AF_INET6, sin6_port=htons(6060),
inet_pton(AF_INET6, "face:b00c:1234:5678::abcd", &sin6_addr),
sin6_flowinfo=0, sin6_scope_id=0}, 128) = 0
# fg
tcpdump -pn -i lo -w connect.pcap 2> /dev/null
# tcpdump -r connect.pcap -n tcp | cut -c 1-72
reading from file connect.pcap, link-type EN10MB (Ethernet)
17:57:40.383533 IP 127.0.0.4.56068 > 127.0.0.1.4444: Flags [S], seq 1333
17:57:40.383566 IP 127.0.0.1.4444 > 127.0.0.4.56068: Flags [S.], seq 112
17:57:40.383589 IP 127.0.0.4.56068 > 127.0.0.1.4444: Flags [.], ack 1, w
17:57:40.384578 IP 127.0.0.1.4444 > 127.0.0.4.56068: Flags [R.], seq 1,
17:57:40.403327 IP6 ::6.37458 > ::1.6666: Flags [S], seq 406513443, win
17:57:40.403357 IP6 ::1.6666 > ::6.37458: Flags [S.], seq 2448389240, ac
17:57:40.403376 IP6 ::6.37458 > ::1.6666: Flags [.], ack 1, win 342, opt
17:57:40.404263 IP6 ::1.6666 > ::6.37458: Flags [R.], seq 1, ack 1, win

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>