selftest: bpf: Test bpf_sk_assign_tcp_reqsk().

This commit adds a sample selftest to demonstrate how we can use
bpf_sk_assign_tcp_reqsk() as the backend of SYN Proxy.

The test creates IPv4/IPv6 x TCP connections and transfer messages
over them on lo with BPF tc prog attached.

The tc prog will process SYN and returns SYN+ACK with the following
ISN and TS. In a real use case, this part will be done by other
hosts.

MSB LSB
ISN: | 31 ... 8 | 7 6 | 5 | 4 | 3 2 1 0 |
| Hash_1 | MSS | ECN | SACK | WScale |

TS: | 31 ... 8 | 7 ... 0 |
| Random | Hash_2 |

WScale in SYN is reused in SYN+ACK.

The client returns ACK, and tc prog will recalculate ISN and TS
from ACK and validate SYN Cookie.

If it's valid, the prog calls kfunc to allocate a reqsk for skb and
configure the reqsk based on the argument created from SYN Cookie.

Later, the reqsk will be processed in cookie_v[46]_check() to create
a connection.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240115205514.68364-7-kuniyu@amazon.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Test udp and tcp iter batching

The patch adds a test to exercise the bpf_iter_udp batching
logic. It specifically tests the case that there are multiple
so_reuseport udp_sk in a bucket of the udp_table.

The test creates two sets of so_reuseport sockets and
each set on a different port. Meaning there will be
two buckets in the udp_table.

The test does the following:
1. read() 3 out of 4 sockets in the first bucket.
2. close() all sockets in the first bucket. This
will ensure the current bucket's offset in
the kernel does not affect the read() of the
following bucket.
3. read() all 4 sockets in the second bucket.

The test also reads one udp_sk at a time from
the bpf_iter_udp prog. The true case in
"do_test(..., bool onebyone)". This is the buggy case
that the previous patch fixed.

It also tests the "false" case in "do_test(..., bool onebyone)",
meaning the userspace reads the whole bucket. There is
no bug in this case but adding this test also while
at it.

Considering the way to have multiple tcp_sk in the same
bucket is similar (by using so_reuseport),
this patch also tests the bpf_iter_tcp even though the
bpf_iter_tcp batching logic works correctly.

Both IP v4 and v6 are exercising the same bpf_iter batching
code path, so only v6 is tested.

Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240112190530.3751661-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

bpf: selftests: test_tunnel: Use vmlinux.h declarations

vmlinux.h declarations are more ergnomic, especially when working with
kfuncs. The uapi headers are often incomplete for kfunc definitions.

This commit also switches bitfield accesses to use CO-RE helpers.
Switching to vmlinux.h definitions makes the verifier very
unhappy with raw bitfield accesses. The error is:

; md.u.md2.dir = direction;
33: (69) r1 = *(u16 *)(r2 +11)
misaligned stack access off (0x0; 0x0)+-64+11 size 2

Fix by using CO-RE-aware bitfield reads and writes.

Co-developed-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/r/884bde1d9a351d126a3923886b945ea6b1b0776b.1702593901.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Check bpf_sk_storage has uncharged sk_omem_alloc

This patch checks the sk_omem_alloc has been uncharged by bpf_sk_storage
during the __sk_destruct.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230901231129.578493-4-martin.lau@linux.dev

selftests/bpf: Test bpf_skb_adjust_room on CHECKSUM_PARTIAL

When the bpf_skb_adjust_room() shrinks the skb such that its csum_start
is invalid, the skb->ip_summed should be reset from CHECKSUM_PARTIAL to
CHECKSUM_NONE.

The commit 54c3f1a81421 ("bpf: pull before calling skb_postpull_rcsum()")
fixed it.

This patch adds a test to ensure the skb->ip_summed changed from
CHECKSUM_PARTIAL to CHECKSUM_NONE after bpf_skb_adjust_room().

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221221185653.1589961-1-martin.lau@linux.dev

selftests/bpf: add xfrm_info tests

Test the xfrm_info kfunc helpers.

The test setup creates three name spaces - NS0, NS1, NS2.

XFRM tunnels are setup between NS0 and the two other NSs.

The kfunc helpers are used to steer traffic from NS0 to the other
NSs based on a userspace populated bpf global variable and validate
that the return traffic had arrived from the desired NS.

Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Link: https://lore.kernel.org/r/20221203084659.1837829-5-eyal.birger@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

selftest/bpf: Add test for bpf_getsockopt()

This patch removes the __bpf_getsockopt() which directly
reads the sk by using PTR_TO_BTF_ID. Instead, the test now directly
uses the kernel bpf helper bpf_getsockopt() which supports all
the required optname now.

TCP_SAVE[D]_SYN and TCP_MAXSEG are not tested in a loop for all
the hooks and sock_ops's cb. TCP_SAVE[D]_SYN only works
in passive connection. TCP_MAXSEG only works when
it is setsockopt before the connection is established and
the getsockopt return value can only be tested after
the connection is established.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002937.2896904-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: bpf_setsockopt tests

This patch adds tests to exercise optnames that are allowed
in bpf_setsockopt().

Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220817061847.4182339-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: lsm_cgroup functional test

Functional test that exercises the following:

1. apply default sk_priority policy
2. permit TX-only AF_PACKET socket
3. cgroup attach/detach/replace
4. reusing trampoline shim

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220628174314.1216643-12-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftest/bpf: Test batching and bpf_(get|set)sockopt in bpf unix iter.

This patch adds a test for the batching and bpf_(get|set)sockopt in bpf
unix iter.

It does the following.

1. Creates an abstract UNIX domain socket
2. Call bpf_setsockopt()
3. Call bpf_getsockopt() and save the value
4. Call setsockopt()
5. Call getsockopt() and save the value
6. Compare the saved values

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Link: https://lore.kernel.org/r/20220113002849.4384-5-kuniyu@amazon.co.jp
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

af_unix: Remove UNIX_ABSTRACT() macro and test sun_path[0] instead.

In BSD and abstract address cases, we store sockets in the hash table with
keys between 0 and UNIX_HASH_SIZE - 1. However, the hash saved in a socket
varies depending on its address type; sockets with BSD addresses always
have UNIX_HASH_SIZE in their unix_sk(sk)->addr->hash.

This is just for the UNIX_ABSTRACT() macro used to check the address type.
The difference of the saved hashes comes from the first byte of the address
in the first place. So, we can test it directly.

Then we can keep a real hash in each socket and replace unix_table_lock
with per-hash locks in the later patch.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftest/bpf: Implement sample UNIX domain socket iterator program.

The iterator can output almost the same result compared to /proc/net/unix.
The header line is aligned, and the Inode column uses "%8lu" because "%5lu"
can be easily overflown.

# cat /sys/fs/bpf/unix
Num RefCount Protocol Flags Type St Inode Path
ffff963c06689800: 00000002 00000000 00010000 0001 01 18697 private/defer
ffff963c7c979c00: 00000002 00000000 00000000 0001 01 598245 @Hello@World@

# cat /proc/net/unix
Num RefCount Protocol Flags Type St Inode Path
ffff963c06689800: 00000002 00000000 00010000 0001 01 18697 private/defer
ffff963c7c979c00: 00000002 00000000 00000000 0001 01 598245 @Hello@World@

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210814015718.42704-4-kuniyu@amazon.co.jp

bpf: selftest: Test batching and bpf_(get|set)sockopt in bpf tcp iter

This patch adds tests for the batching and bpf_(get|set)sockopt in
bpf tcp iter.

It first creates:
a) 1 non SO_REUSEPORT listener in lhash2.
b) 256 passive and active fds connected to the listener in (a).
c) 256 SO_REUSEPORT listeners in one of the lhash2 bucket.

The test sets all listeners and connections to bpf_cubic before
running the bpf iter.

The bpf iter then calls setsockopt(TCP_CONGESTION) to switch
each listener and connection from bpf_cubic to bpf_dctcp.

The bpf iter has a random_retry mode such that it can return EAGAIN
to the usespace in the middle of a batch.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200625.1036874-1-kafai@fb.com

selftests/bpf: Add more common macros to bpf_tracing_net.h

These newly added macros will be used in subsequent bpf iterator
tcp{4,6} and udp{4,6} programs.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230819.3989050-1-yhs@fb.com

selftests/bpf: Refactor some net macros to bpf_tracing_net.h

Refactor bpf_iter_ipv6_route.c and bpf_iter_netlink.c
so net macros, originally from various include/linux header
files, are moved to a new header file
bpf_tracing_net.h. The goal is to improve reuse so
networking tracing programs do not need to
copy these macros every time they use them.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230817.3988962-1-yhs@fb.com