tests/shell: skip test in rootless that hit socket buffer size limit

The socket buffer limits like /proc/sys/net/core/{rmem_max,wmem_max}
can cause tests to fail, when running rootless. That's because real-root
can override those limits, rootless cannot.

Add an environment variable NFT_TEST_HAS_SOCKET_LIMITS=*|n which is
automatically set by "run-tests.sh".

Certain tests will check for [ "$NFT_TEST_HAS_SOCKET_LIMITS" = y ] and
skip the test.

The user may manually bump those limits (requires root), and set
NFT_TEST_HAS_SOCKET_LIMITS=n to get the tests to pass even as rootless.

For example, the test passes with root:

  sudo ./tests/shell/run-tests.sh -- tests/shell/testcases/sets/automerge_0

Without root, it would fail. Skip it instead:

  ./tests/shell/run-tests.sh -- tests/shell/testcases/sets/automerge_0
  ...
  I: [SKIPPED]    tests/shell/testcases/sets/automerge_0

Or bump the limit:

  $ echo 3000000 | sudo tee /proc/sys/net/core/wmem_max
  $ NFT_TEST_HAS_SOCKET_LIMITS=n ./tests/shell/run-tests.sh -- tests/shell/testcases/sets/automerge_0
  ...
  I: [OK]         tests/shell/testcases/sets/automerge_0

Signed-off-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/shell/testcases/sets/0013add_delete_many_elements_0 b/tests/shell/testcases/sets/0013add_delete_many_elements_0
index 5774317b..c0925dd5 100755
--- a/tests/shell/testcases/sets/0013add_delete_many_elements_0
+++ b/tests/shell/testcases/sets/0013add_delete_many_elements_0
@@ -3,6 +3,13 @@
 # test adding and deleting many sets elements in two nft -f runs.
 
 HOWMANY=255
+if [ "$NFT_TEST_HAS_SOCKET_LIMITS" = y ] ; then
+	# The socket limit /proc/sys/net/core/wmem_max may be unsuitable for
+	# the test.
+	#
+	# Run only a subset of the test and mark as skipped at the end.
+	HOWMANY=30
+fi
 
 tmpfile=$(mktemp)
 if [ ! -w $tmpfile ] ; then
@@ -32,3 +39,10 @@ add element x y $(generate)" > $tmpfile
 $NFT -f $tmpfile
 echo "delete element x y $(generate)" > $tmpfile
 $NFT -f $tmpfile
+
+if [ "$HOWMANY" != 255 ] ; then
+	echo "NFT_TEST_HAS_SOCKET_LIMITS indicates that the socket limit for"
+	echo "/proc/sys/net/core/wmem_max is too small for this test. Mark as SKIPPED"
+	echo "You may bump the limit and rerun with \`NFT_TEST_HAS_SOCKET_LIMITS=n\`."
+	exit 77
+fi