1 files changed, 85 insertions, 0 deletions
diff --git a/tests/pytests/conn_flood.py b/tests/pytests/conn_flood.py
new file mode 100644
index 0000000..88bbfa5
--- /dev/null
+++ b/tests/pytests/conn_flood.py
@@ -0,0 +1,85 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+"""Test opening as many connections as possible.
+
+Due to resource-intensity of this test, it's filename doesn't contain
+"test" on purpose, so it doesn't automatically get picked up by pytest
+(to allow easy parallel testing).
+
+To execute this test, pass the filename of this file to pytest directly.
+Also, make sure not to use parallel execution (-n).
+"""
+
+import resource
+import time
+
+import pytest
+
+from kresd import Kresd
+import utils
+
+
+MAX_SOCKETS = 10000  # upper bound of how many connections to open
+MAX_ITERATIONS = 10  # number of iterations to run the test
+
+# we can't use softlimit itself since kresd already has open sockets,
+# so use lesser value
+RESERVED_NOFILE = 40  # 40 is empirical value
+
+
+@pytest.mark.parametrize('sock_func_name', [
+    'ip_tcp_socket',
+    'ip6_tcp_socket',
+    'ip_tls_socket',
+    'ip6_tls_socket',
+])
+def test_conn_flood(tmpdir, sock_func_name):
+    def create_sockets(make_sock, nsockets):
+        sockets = []
+        next_ping = time.time() + 4  # less than tcp idle timeout / 2
+        while True:
+            additional_sockets = 0
+            while time.time() < next_ping:
+                nsock_to_init = min(100, nsockets - len(sockets))
+                if not nsock_to_init:
+                    return sockets
+                sockets.extend([make_sock() for _ in range(nsock_to_init)])
+                additional_sockets += nsock_to_init
+
+            # large number of connections can take a lot of time to open
+            # send some valid data to avoid TCP idle timeout for already open sockets
+            next_ping = time.time() + 4
+            for s in sockets:
+                utils.ping_alive(s)
+
+            # break when no more than 20% additional sockets are created
+            if additional_sockets / len(sockets) < 0.2:
+                return sockets
+
+    max_num_of_open_files = resource.getrlimit(resource.RLIMIT_NOFILE)[0] - RESERVED_NOFILE
+    nsockets = min(max_num_of_open_files, MAX_SOCKETS)
+
+    # create kresd instance with verbose=False
+    ip = '127.0.0.1'
+    ip6 = '::1'
+    with Kresd(tmpdir, ip=ip, ip6=ip6, verbose=False) as kresd:
+        make_sock = getattr(kresd, sock_func_name)  # function for creating sockets
+        sockets = create_sockets(make_sock, nsockets)
+        print("\nEstablished {} connections".format(len(sockets)))
+
+        print("Start sending data")
+        for i in range(MAX_ITERATIONS):
+            for s in sockets:
+                utils.ping_alive(s)
+            print("Iteration {} done...".format(i))
+
+        print("Close connections")
+        for s in sockets:
+            s.close()
+
+        # check in kresd is alive
+        print("Check upstream is still alive")
+        sock = make_sock()
+        utils.ping_alive(sock)
+
+        print("OK!")