On 08/09, Kui-Feng Lee wrote: > Capture packets in the background for flaky test cases related to > network features. > > We have some flaky test cases that are difficult to debug without > knowing what the traffic looks like. Capturing packets, the CI log and > packet files may help developers to fix these flaky test cases. > > This patch set monitors a few test cases. Recently, they have been > showing flaky behavior. > > lo In IPv4 127.0.0.1:40265 > 127.0.0.1:55907: TCP, length 68, SYN > lo In IPv4 127.0.0.1:55907 > 127.0.0.1:40265: TCP, length 60, SYN, ACK > lo In IPv4 127.0.0.1:40265 > 127.0.0.1:55907: TCP, length 60, ACK > lo In IPv4 127.0.0.1:55907 > 127.0.0.1:40265: TCP, length 52, ACK > lo In IPv4 127.0.0.1:40265 > 127.0.0.1:55907: TCP, length 52, FIN, ACK > lo In IPv4 127.0.0.1:55907 > 127.0.0.1:40265: TCP, length 52, RST, ACK > Packet file: packets-2173-86-select_reuseport:sockhash_IPv4_TCP_LOOPBACK_test_detach_bpf-test.log > #280/87 select_reuseport/sockhash IPv4/TCP LOOPBACK test_detach_bpf:OK > > The above block is the log of a test case. It shows every packet of a > connection. The captured packets are stored in the file called > packets-2173-86-select_reuseport:sockhash_IPv4_TCP_LOOPBACK_test_detach_bpf-test.log. > > We have a set of high-level helpers and a test_progs option to > simplify the process of enabling the traffic monitor. netns_new() and > netns_free() are helpers used to create and delete namespaces while > also enabling the traffic monitor for the namespace based on the > patterns provided by the "-m" option of test_progs. The value of the > "-m" option is a list of patterns used to enable the traffic monitor > for a group of tests or a file containing patterns. CI can utilize > this option to enable monitoring. > > traffic_monitor_start() and traffic_monitor_stop() are low-level > functions to start monitoring explicitly. You can have more controls, > however high-level helpers are preferred. > > The following block is an example that monitors the network traffic of > a test case in a network namespace. > > struct netns_obj *netns; > > ... > netns = netns_new("test", true); > if (!ASSERT_TRUE(netns, "netns_new")) > goto err; > > ... test ... > > netns_free(netns); > > netns_new() will create a network namespace named "test" and bring up > "lo" in the namespace. By passing "true" as the 2nd argument, it will > set the network namespace of the current process to > "test".netns_free() will destroy the namespace, and the process will > leave the "test" namespace if the struct netns_obj returned by > netns_new() is created with "true" as the 2nd argument. If the name of > the test matches the patterns given by the "-m" option, the traffic > monitor will be enabled for the "test" namespace as well. > > The packet files are located in the directory "/tmp/tmon_pcap/". The > directory is intended to be compressed as a file so that developers > can download it from the CI. > > This feature is enabled only if libpcap is available when building > selftests. Acked-by: Stanislav Fomichev <sdf@xxxxxxxxxxx>