Add another regression test for issue 3100 (#3570)

Closes #3100. This is the second example simulation in that issue.

Author: stevenengler

CHANGELOG.md

@@ -59,7 +59,7 @@ to sort out in the case that `stdout` and `stderr` are merged. (#3428)
   as the obfs4proxy pluggable transport (#3538). (#3542)
 * Fixed the behavior of sockets bound to the loopback interface: Shadow no longer panics in some cases where `connect` and `sendmsg` syscalls are used with a non-loopback address. (#3531)
 * Fixed the behaviour of an implicit bind during a `sendmsg` syscall for UDP sockets. (#3545)
-* Fixed a bug in `shutdown()` for TCP sockets, causing the FIN packet to be sent out of order. (#3562)
+* Fixed a TCP socket bug causing the FIN packet to be sent out of order. (#3562, #3570)
 
 Full changelog since v3.2.0:
 

src/test/regression/3100/CMakeLists.txt

@@ -1,2 +1,3 @@
-# regression test for https://github.com/shadow/shadow/issues/3100
-add_shadow_tests(BASENAME regression-3100)
+# regression tests for https://github.com/shadow/shadow/issues/3100
+add_shadow_tests(BASENAME regression-3100-a)
+add_shadow_tests(BASENAME regression-3100-b)

src/test/regression/3100/regression-3100.yaml renamed to src/test/regression/3100/regression-3100-a.yaml

@@ -1,5 +1,8 @@
 general:
   stop_time: 10 seconds
+  # disable this explicitly since the default may change to 'true' in the future,
+  # and if this were enabled it might mask the issue by inserting a delay between the send and the shutdown
+  model_unblocked_syscall_latency: false
 network:
   graph:
     type: 1_gbit_switch

src/test/regression/3100/regression-3100-b.yaml

@@ -0,0 +1,63 @@
+general:
+  stop_time: 60 seconds
+  # disable this explicitly since the default may change to 'true' in the future,
+  # and if this were enabled it might mask the issue by inserting a delay between the send and the close
+  model_unblocked_syscall_latency: false
+network:
+  graph:
+    type: gml
+    inline: |
+      graph [
+        directed 0
+        node [
+          id 0
+          host_bandwidth_up "1 Mbit"
+          host_bandwidth_down "1 Mbit"
+        ]
+        edge [
+          source 0
+          target 0
+          latency "500 ms"
+          packet_loss 0.0
+        ]
+      ]
+hosts:
+  server:
+    network_node_id: 0
+    processes:
+    - path: python3
+      args:
+        - '-u'
+        - '-c'
+        - |
+          import socket, time
+          server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+          server.bind(('0.0.0.0', 8080))
+          server.listen(100)
+          (s, _) = server.accept()
+          server.close()
+          print("Accepted socket")
+
+          # read bytes until EOF
+          while True:
+            n = len(s.recv(1000))
+            if n == 0:
+              break
+  client:
+    network_node_id: 0
+    processes:
+    - path: python3
+      start_time: 100 ms
+      args:
+        - '-u'
+        - '-c'
+        - |
+          import socket, time
+          s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+          s.connect(('server', 8080))
+          print("Connected")
+
+          # send some bytes and then immediately close,
+          # which should send a FIN after the bytes
+          s.send(b'hello')
+          s.close()