Merge branch 'bpf-fix-wrong-copied_seq-calculation-and-add-tests'

Jiayuan Chen says:

====================
A previous commit described in this topic
http://lore.kernel.org/bpf/20230523025618.113937-9-john.fastabend@gmail.com
directly updated 'sk->copied_seq' in the tcp_eat_skb() function when the
action of a BPF program was SK_REDIRECT. For other actions, like SK_PASS,
the update logic for 'sk->copied_seq' was moved to
tcp_bpf_recvmsg_parser() to ensure the accuracy of the 'fionread' feature.

That commit works for a single stream_verdict scenario, as it also
modified 'sk_data_ready->sk_psock_verdict_data_ready->tcp_read_skb'
to remove updating 'sk->copied_seq'.

However, for programs where both stream_parser and stream_verdict are
active (strparser purpose), tcp_read_sock() was used instead of
tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock).
tcp_read_sock() now still updates 'sk->copied_seq', leading to duplicated
updates.

In summary, for strparser + SK_PASS, copied_seq is redundantly calculated
in both tcp_read_sock() and tcp_bpf_recvmsg_parser().

The issue causes incorrect copied_seq calculations, which prevent
correct data reads from the recv() interface in user-land.

Also we added test cases for bpf + strparser and separated them from
sockmap_basic, as strparser has more encapsulation and parsing
capabilities compared to sockmap.
====================

Link: https://patch.msgid.link/20250122100917.49845-1-mrpre@163.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

1 files changed, 3 insertions, 56 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
index 884ad87783d5..f8953455db29 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
@@ -522,8 +522,8 @@ static void test_sockmap_skb_verdict_shutdown(void)
 	if (!ASSERT_EQ(err, 1, "epoll_wait(fd)"))
 		goto out_close;
 
-	n = recv(c1, &b, 1, SOCK_NONBLOCK);
-	ASSERT_EQ(n, 0, "recv_timeout(fin)");
+	n = recv(c1, &b, 1, MSG_DONTWAIT);
+	ASSERT_EQ(n, 0, "recv(fin)");
 out_close:
 	close(c1);
 	close(p1);
@@ -531,57 +531,6 @@ out:
 	test_sockmap_pass_prog__destroy(skel);
 }
 
-static void test_sockmap_stream_pass(void)
-{
-	int zero = 0, sent, recvd;
-	int verdict, parser;
-	int err, map;
-	int c = -1, p = -1;
-	struct test_sockmap_pass_prog *pass = NULL;
-	char snd[256] = "0123456789";
-	char rcv[256] = "0";
-
-	pass = test_sockmap_pass_prog__open_and_load();
-	verdict = bpf_program__fd(pass->progs.prog_skb_verdict);
-	parser = bpf_program__fd(pass->progs.prog_skb_parser);
-	map = bpf_map__fd(pass->maps.sock_map_rx);
-
-	err = bpf_prog_attach(parser, map, BPF_SK_SKB_STREAM_PARSER, 0);
-	if (!ASSERT_OK(err, "bpf_prog_attach stream parser"))
-		goto out;
-
-	err = bpf_prog_attach(verdict, map, BPF_SK_SKB_STREAM_VERDICT, 0);
-	if (!ASSERT_OK(err, "bpf_prog_attach stream verdict"))
-		goto out;
-
-	err = create_pair(AF_INET, SOCK_STREAM, &c, &p);
-	if (err)
-		goto out;
-
-	/* sk_data_ready of 'p' will be replaced by strparser handler */
-	err = bpf_map_update_elem(map, &zero, &p, BPF_NOEXIST);
-	if (!ASSERT_OK(err, "bpf_map_update_elem(p)"))
-		goto out_close;
-
-	/*
-	 * as 'prog_skb_parser' return the original skb len and
-	 * 'prog_skb_verdict' return SK_PASS, the kernel will just
-	 * pass it through to original socket 'p'
-	 */
-	sent = xsend(c, snd, sizeof(snd), 0);
-	ASSERT_EQ(sent, sizeof(snd), "xsend(c)");
-
-	recvd = recv_timeout(p, rcv, sizeof(rcv), SOCK_NONBLOCK,
-			     IO_TIMEOUT_SEC);
-	ASSERT_EQ(recvd, sizeof(rcv), "recv_timeout(p)");
-
-out_close:
-	close(c);
-	close(p);
-
-out:
-	test_sockmap_pass_prog__destroy(pass);
-}
 
 static void test_sockmap_skb_verdict_fionread(bool pass_prog)
 {
@@ -628,7 +577,7 @@ static void test_sockmap_skb_verdict_fionread(bool pass_prog)
 	ASSERT_EQ(avail, expected, "ioctl(FIONREAD)");
 	/* On DROP test there will be no data to read */
 	if (pass_prog) {
-		recvd = recv_timeout(c1, &buf, sizeof(buf), SOCK_NONBLOCK, IO_TIMEOUT_SEC);
+		recvd = recv_timeout(c1, &buf, sizeof(buf), MSG_DONTWAIT, IO_TIMEOUT_SEC);
 		ASSERT_EQ(recvd, sizeof(buf), "recv_timeout(c0)");
 	}
 
@@ -1101,8 +1050,6 @@ void test_sockmap_basic(void)
 		test_sockmap_progs_query(BPF_SK_SKB_VERDICT);
 	if (test__start_subtest("sockmap skb_verdict shutdown"))
 		test_sockmap_skb_verdict_shutdown();
-	if (test__start_subtest("sockmap stream parser and verdict pass"))
-		test_sockmap_stream_pass();
 	if (test__start_subtest("sockmap skb_verdict fionread"))
 		test_sockmap_skb_verdict_fionread(true);
 	if (test__start_subtest("sockmap skb_verdict fionread on drop"))