Address of closed listening socket isn't immediately available for reuse #3650
Description
When a listening socket is closed and the plugin attempts to immediately bind a new socket to the same address, the bind will fail.
For example see this workaround in one of our tests.
shadow/src/test/socket/bind/test_bind.rs
Lines 252 to 255 in d9c7c07
I believe that this bug is preventing netcat from working correctly in Shadow: #3564
Here's an example that reproduces the issue.
general:
stop_time: 30s
#model_unblocked_syscall_latency: true
experimental:
strace_logging_mode: standard
#max_unapplied_cpu_latency: 1 ns
network:
graph:
type: 1_gbit_switch
hosts:
server:
network_node_id: 0
processes:
- path: python3
args:
- '-u'
- '-c'
- |
import socket
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind(('0.0.0.0', 8080))
server.listen(100)
print("Listening")
(s, _) = server.accept()
s.close()
print("Accepted socket")
server.close()
print("Closed listening socket")
# all sockets have been closed, so we expect this to work
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind(('0.0.0.0', 8080))
server.listen(100)
server.close()
client:
network_node_id: 0
processes:
- path: python3
start_time: 100 ms
expected_final_state: running
args:
- '-u'
- '-c'
- |
import socket, time
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('server', 8080))
print("Connected")
# don't close the socket, we want to keep the socket open until the
# end of the simulation so that closing the socket doesn't send a FIN
print("Sleeping")
time.sleep(100000)Traceback (most recent call last):
File "<string>", line 19, in <module>
server.bind(('0.0.0.0', 8080))
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
OSError: [Errno 98] Address already in use
Note that if you uncomment the model_unblocked_syscall_latency and max_unapplied_cpu_latency lines, or if you add a short sleep before the second server bind, the simulation will succeed.