[PATCH mptcp-next v2 7/7] selftests: mptcp: sockopt: check app_limited

From: Geliang Tang <[email protected]>

connect_one_server() in mptcp_sockopt exchanges only a few packets between
the client and server, then closes the socket. After such a small transfer
the application has nothing further to send, so the connection is, by
definition, application-limited.

Extend the TCP_INFO readback at the end of the function to assert
s.tcp_info.tcpi_delivery_rate_app_limited == 1.

Without the preceding commit, mptcp_sendmsg() never updates the per-subflow
app-limited state, and this field stays at 0 - the assertion would fail.
With it in place, the value is forced to 1, turning this into a regression
guard for the subflow-side application-limited accounting.

Signed-off-by: Geliang Tang <[email protected]>
---
 tools/testing/selftests/net/mptcp/mptcp_sockopt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
index d68515b7903b..8d712bdb4325 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
@@ -640,6 +640,7 @@ static void connect_one_server(int fd, int pipefd)
 		total += 1; /* sequence advances due to FIN */
 
 	assert(s.mptcpi_rcv_delta == (uint64_t)total);
+	assert(s.tcp_info.tcpi_delivery_rate_app_limited == 1);
 	close(fd);
 }
 
-- 
2.53.0