1 files changed, 61 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/tcp_rtt.c b/tools/testing/selftests/bpf/progs/tcp_rtt.c
new file mode 100644
index 000000000000..233bdcb1659e
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tcp_rtt.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+__u32 _version SEC("version") = 1;
+
+struct tcp_rtt_storage {
+	__u32 invoked;
+	__u32 dsack_dups;
+	__u32 delivered;
+	__u32 delivered_ce;
+	__u32 icsk_retransmits;
+};
+
+struct bpf_map_def SEC("maps") socket_storage_map = {
+	.type = BPF_MAP_TYPE_SK_STORAGE,
+	.key_size = sizeof(int),
+	.value_size = sizeof(struct tcp_rtt_storage),
+	.map_flags = BPF_F_NO_PREALLOC,
+};
+BPF_ANNOTATE_KV_PAIR(socket_storage_map, int, struct tcp_rtt_storage);
+
+SEC("sockops")
+int _sockops(struct bpf_sock_ops *ctx)
+{
+	struct tcp_rtt_storage *storage;
+	struct bpf_tcp_sock *tcp_sk;
+	int op = (int) ctx->op;
+	struct bpf_sock *sk;
+
+	sk = ctx->sk;
+	if (!sk)
+		return 1;
+
+	storage = bpf_sk_storage_get(&socket_storage_map, sk, 0,
+				     BPF_SK_STORAGE_GET_F_CREATE);
+	if (!storage)
+		return 1;
+
+	if (op == BPF_SOCK_OPS_TCP_CONNECT_CB) {
+		bpf_sock_ops_cb_flags_set(ctx, BPF_SOCK_OPS_RTT_CB_FLAG);
+		return 1;
+	}
+
+	if (op != BPF_SOCK_OPS_RTT_CB)
+		return 1;
+
+	tcp_sk = bpf_tcp_sock(sk);
+	if (!tcp_sk)
+		return 1;
+
+	storage->invoked++;
+
+	storage->dsack_dups = tcp_sk->dsack_dups;
+	storage->delivered = tcp_sk->delivered;
+	storage->delivered_ce = tcp_sk->delivered_ce;
+	storage->icsk_retransmits = tcp_sk->icsk_retransmits;
+
+	return 1;
+}