[PATCH bpf-next v2 3/3] selftests/bpf: add rto max for bpf_setsockopt test

[Jason Xing <kerneljasonxing@gmail.com>]

Add TCP_RTO_MAX_MS selftests for active and passive flows
in various bpf callbacks. Even though the TCP_RTO_MAX_MS
can be used in established phase, we highly discourage
to do so because it may trigger unexpected behaviour.
On the contrary, it's highly recommended that the maximum
value of RTO is set before first time of transmission, such
as BPF_SOCK_OPS_{PASSIVE|ACTIVE}_ESTABLISHED_CB,

Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
---
 tools/include/uapi/linux/tcp.h                      | 1 +
 tools/testing/selftests/bpf/progs/bpf_tracing_net.h | 1 +
 tools/testing/selftests/bpf/progs/setget_sockopt.c  | 1 +
 3 files changed, 3 insertions(+)

diff --git a/tools/include/uapi/linux/tcp.h b/tools/include/uapi/linux/tcp.h
index 13ceeb395eb8..7989e3f34a58 100644
--- a/tools/include/uapi/linux/tcp.h
+++ b/tools/include/uapi/linux/tcp.h
@@ -128,6 +128,7 @@ enum {
 #define TCP_CM_INQ		TCP_INQ
 
 #define TCP_TX_DELAY		37	/* delay outgoing packets by XX usec */
+#define TCP_RTO_MAX_MS		44	/* max rto time in ms */
 
 
 #define TCP_REPAIR_ON		1
diff --git a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
index 59843b430f76..eb6ed1b7b2ef 100644
--- a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
+++ b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
@@ -49,6 +49,7 @@
 #define TCP_SAVED_SYN		28
 #define TCP_CA_NAME_MAX		16
 #define TCP_NAGLE_OFF		1
+#define TCP_RTO_MAX_MS		44
 
 #define TCP_ECN_OK              1
 #define TCP_ECN_QUEUE_CWR       2
diff --git a/tools/testing/selftests/bpf/progs/setget_sockopt.c b/tools/testing/selftests/bpf/progs/setget_sockopt.c
index 6dd4318debbf..106fe430f41b 100644
--- a/tools/testing/selftests/bpf/progs/setget_sockopt.c
+++ b/tools/testing/selftests/bpf/progs/setget_sockopt.c
@@ -61,6 +61,7 @@ static const struct sockopt_test sol_tcp_tests[] = {
 	{ .opt = TCP_NOTSENT_LOWAT, .new = 1314, .expected = 1314, },
 	{ .opt = TCP_BPF_SOCK_OPS_CB_FLAGS, .new = BPF_SOCK_OPS_ALL_CB_FLAGS,
 	  .expected = BPF_SOCK_OPS_ALL_CB_FLAGS, },
+	{ .opt = TCP_RTO_MAX_MS, .new = 2000, .expected = 2000, },
 	{ .opt = 0, },
 };
 
-- 
2.43.5