[PATCH bpf-next v4 7/7] selftests/bpf: verify first of struct mptcp_sock

[Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>]

From: Geliang Tang <geliang.tang@xxxxxxxx>

This patch verifies the 'first' struct member of struct mptcp_sock, which
points to the first subflow of msk. Save 'sk' in mptcp_storage, and verify
it with 'first' in verify_msk().

Acked-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
Signed-off-by: Geliang Tang <geliang.tang@xxxxxxxx>
Signed-off-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>
---
 tools/testing/selftests/bpf/bpf_tcp_helpers.h  | 1 +
 tools/testing/selftests/bpf/prog_tests/mptcp.c | 8 ++++++++
 tools/testing/selftests/bpf/progs/mptcp_sock.c | 5 +++++
 3 files changed, 14 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_tcp_helpers.h b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
index c38c66d5c1e6..82a7c9de95f9 100644
--- a/tools/testing/selftests/bpf/bpf_tcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
@@ -234,6 +234,7 @@ struct mptcp_sock {
 	struct inet_connection_sock	sk;
 
 	__u32		token;
+	struct sock	*first;
 	char		ca_name[TCP_CA_NAME_MAX];
 } __attribute__((preserve_access_index));
 
diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index 2ff7f18ea0ce..51a3e17acb9e 100644
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -13,7 +13,9 @@
 struct mptcp_storage {
 	__u32 invoked;
 	__u32 is_mptcp;
+	struct sock *sk;
 	__u32 token;
+	struct sock *first;
 	char ca_name[TCP_CA_NAME_MAX];
 };
 
@@ -136,6 +138,12 @@ static int verify_msk(int map_fd, int client_fd)
 		err++;
 	}
 
+	if (val.first != val.sk) {
+		log_err("Unexpected mptcp_sock.first %p != %p",
+			val.first, val.sk);
+		err++;
+	}
+
 	if (strncmp(val.ca_name, ca_name, TCP_CA_NAME_MAX)) {
 		log_err("Unexpected mptcp_sock.ca_name %s != %s",
 			val.ca_name, ca_name);
diff --git a/tools/testing/selftests/bpf/progs/mptcp_sock.c b/tools/testing/selftests/bpf/progs/mptcp_sock.c
index c36f2f6bd2f1..ab135edf3ae3 100644
--- a/tools/testing/selftests/bpf/progs/mptcp_sock.c
+++ b/tools/testing/selftests/bpf/progs/mptcp_sock.c
@@ -13,7 +13,9 @@ extern bool CONFIG_MPTCP __kconfig;
 struct mptcp_storage {
 	__u32 invoked;
 	__u32 is_mptcp;
+	struct sock *sk;
 	__u32 token;
+	struct sock *first;
 	char ca_name[TCP_CA_NAME_MAX];
 };
 
@@ -54,6 +56,7 @@ int _sockops(struct bpf_sock_ops *ctx)
 
 		storage->token = 0;
 		bzero(storage->ca_name, TCP_CA_NAME_MAX);
+		storage->first = NULL;
 	} else {
 		if (!CONFIG_MPTCP)
 			return 1;
@@ -69,9 +72,11 @@ int _sockops(struct bpf_sock_ops *ctx)
 
 		storage->token = msk->token;
 		memcpy(storage->ca_name, msk->ca_name, TCP_CA_NAME_MAX);
+		storage->first = msk->first;
 	}
 	storage->invoked++;
 	storage->is_mptcp = is_mptcp;
+	storage->sk = (struct sock *)sk;
 
 	return 1;
 }
-- 
2.36.1