commit f1231b26342240949f4186bedc5b452fb0e55e5c
author Chenbo Feng <fengc@google.com> Fri May 11 17:24:51 2018 -0700
committer Chenbo Feng <fengc@google.com> Fri May 11 17:32:01 2018 -0700
tree 8ccd372c37cc60b81e555d9691caa677dd27690d
parent 493cfb50cb18677628f0ae62dd8a14036a8eec0c

Fix the flaky cgroup uid bpf test

The cgroup uid traffic test is recording all the packets through the
default uid (usually root uid). If there are other networking traffic
happens when the test is running on a device, the total packets count
will be incorrect. This can be fixed by generating traffic in a socket
belong to a special test uid.

Test: bpf_test pass on device
Bug: 79488922
Change-Id: I34089336e48a0b1ffb6d5a5344dea444494c39dd

net/test/bpf_test.py

diff --git a/net/test/bpf_test.py b/net/test/bpf_test.py
index e7a4edb..270243e 100755
--- a/net/test/bpf_test.py
+++ b/net/test/bpf_test.py
@@ -33,6 +33,7 @@
 KEY_SIZE = 8
 VALUE_SIZE = 4
 TOTAL_ENTRIES = 20
+TEST_UID = 54321
 # Offset to store the map key in stack register REG10
 key_offset = -8
 # Offset to store the map value in stack register REG10
@@ -300,7 +301,7 @@
                      + INS_SK_FILTER_ACCEPT)
     self.prog_fd = BpfProgLoad(BPF_PROG_TYPE_SOCKET_FILTER, instructions)
     packet_count = 10
-    uid = 12345
+    uid = TEST_UID
     with net_test.RunAsUid(uid):
       self.assertRaisesErrno(errno.ENOENT, LookupMap, self.map_fd, uid)
       SocketUDPLoopBack(packet_count, 4, self.prog_fd)
@@ -385,13 +386,15 @@
                      + INS_CGROUP_ACCEPT + INS_PACK_COUNT_UPDATE + INS_CGROUP_ACCEPT)
     self.prog_fd = BpfProgLoad(BPF_PROG_TYPE_CGROUP_SKB, instructions)
     BpfProgAttach(self.prog_fd, self._cg_fd, BPF_CGROUP_INET_INGRESS)
-    uid = os.getuid()
     packet_count = 20
-    SocketUDPLoopBack(packet_count, 4, None)
-    self.assertEquals(packet_count, LookupMap(self.map_fd, uid).value)
-    DeleteMap(self.map_fd, uid);
-    SocketUDPLoopBack(packet_count, 6, None)
-    self.assertEquals(packet_count, LookupMap(self.map_fd, uid).value)
+    uid = TEST_UID
+    with net_test.RunAsUid(uid):
+      self.assertRaisesErrno(errno.ENOENT, LookupMap, self.map_fd, uid)
+      SocketUDPLoopBack(packet_count, 4, None)
+      self.assertEquals(packet_count, LookupMap(self.map_fd, uid).value)
+      DeleteMap(self.map_fd, uid);
+      SocketUDPLoopBack(packet_count, 6, None)
+      self.assertEquals(packet_count, LookupMap(self.map_fd, uid).value)
     BpfProgDetach(self._cg_fd, BPF_CGROUP_INET_INGRESS)
 
 if __name__ == "__main__":