Set closed global file descriptors to -1

[WatcherOfTheSkies]

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• Version of iperf3 (or development branch, such as master or
  3.1-STABLE) to which this pull request applies:
  master

• Issues fixed (if any):
  It's just good management to set a file descriptor to -1 when it's been closed.

• Brief description of code changes (suitable for use as a commit message):
  All the FDs which are global have been set to -1 after closing.

[WatcherOfTheSkies]

My test seems to be OK...

./src/iperf3 -c localhost -V -t 5 -T test1
test1: iperf 3.20+
test1: test1: Linux raspberrypi 6.1.21-v8+ #1642 SMP PREEMPT Mon Apr 3 17:24:16 BST 2023 aarch64
Control connection MSS 32732
test1: Time: Thu, 01 Jan 1970 00:30:14 GMT
test1: Connecting to host localhost, port 5201
test1: Cookie: dap67v5if7oefignr7g3pqbznzvnxwo2pnjk
test1: TCP MSS: 32732 (default)
test1: [ 5] local ::1 port 39548 connected to ::1 port 5201
test1: Starting Test: protocol: TCP, 1 streams, 131072 byte blocks, omitting 0 seconds, 5 second test, tos 0
test1: [ ID] Interval Transfer Bitrate Retr Cwnd
test1: [ 5] 0.00-1.00 sec 1.15 GBytes 9.87 Gbits/sec 0 1.31 MBytes
test1: [ 5] 1.00-2.00 sec 1.17 GBytes 10.1 Gbits/sec 0 1.31 MBytes
test1: [ 5] 2.00-3.00 sec 1.20 GBytes 10.3 Gbits/sec 0 1.31 MBytes
test1: [ 5] 3.00-4.00 sec 1.13 GBytes 9.70 Gbits/sec 0 1.31 MBytes
test1: [ -1] 4.00-5.00 sec 1.18 GBytes 10.1 Gbits/sec 0 1.31 MBytes
test1: - - - - - - - - - - - - - - - - - - - - - - - - -
test1: Test Complete. Summary Results:
test1: [ ID] Interval Transfer Bitrate Retr
test1: [ -1] 0.00-5.00 sec 5.88 GBytes 10.1 Gbits/sec 0 sender
test1: [ -1] 0.00-5.01 sec 5.88 GBytes 10.1 Gbits/sec receiver
test1: CPU Utilization: local/sender 98.9% (2.1%u/96.8%s), remote/receiver 90.2% (3.3%u/86.9%s)
test1: snd_tcp_congestion cubic
test1: rcv_tcp_congestion cubic
test1:
test1: iperf Done.

[WatcherOfTheSkies]

Hi. Does your install include sudo ldconfig after sudo make install?. Thanks!

[WatcherOfTheSkies]

Further testing shows that...

./test_commands.sh localhost

works on a Raspberry Pi but not on Ubuntu as per your tests.

[davidBar-On]

Note also that even in the successful tests, the Socket ID in the last lines of the statistics reports is "-1". E.g. from the build-test-macos-ish:

Starting Test: protocol: UDP, 1 streams, 16312 byte blocks, omitting 0 seconds, 5 second test, tos 0
[ ID] Interval           Transfer     Bitrate         Total Datagrams
[  7]   0.00-1.05   sec   127 KBytes   992 Kbits/sec  8  
[  7]   1.05-2.00   sec   143 KBytes  1.24 Mbits/sec  9  
[  7]   2.00-3.07   sec   127 KBytes   976 Kbits/sec  8  
[  7]   3.07-4.07   sec   127 KBytes  1.04 Mbits/sec  8  
[ -1]   4.07-5.02   sec   127 KBytes  1.11 Mbits/sec  8  
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval           Transfer     Bitrate         Jitter    Lost/Total Datagrams
[ -1]   0.00-5.02   sec   653 KBytes  1.07 Mbits/sec  0.000 ms  0/41 (0%)  sender
[ -1]   0.00-5.02   sec   653 KBytes  1.07 Mbits/sec  0.878 ms  0/41 (0%)  receiver

[WatcherOfTheSkies]

Note also that even in the successful tests, the Socket ID in the last lines of the statistics reports is "-1". E.g. from the build-test-macos-ish:

Starting Test: protocol: UDP, 1 streams, 16312 byte blocks, omitting 0 seconds, 5 second test, tos 0
[ ID] Interval           Transfer     Bitrate         Total Datagrams
[  7]   0.00-1.05   sec   127 KBytes   992 Kbits/sec  8  
[  7]   1.05-2.00   sec   143 KBytes  1.24 Mbits/sec  9  
[  7]   2.00-3.07   sec   127 KBytes   976 Kbits/sec  8  
[  7]   3.07-4.07   sec   127 KBytes  1.04 Mbits/sec  8  
[ -1]   4.07-5.02   sec   127 KBytes  1.11 Mbits/sec  8  
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval           Transfer     Bitrate         Jitter    Lost/Total Datagrams
[ -1]   0.00-5.02   sec   653 KBytes  1.07 Mbits/sec  0.000 ms  0/41 (0%)  sender
[ -1]   0.00-5.02   sec   653 KBytes  1.07 Mbits/sec  0.878 ms  0/41 (0%)  receiver

Good spot! I'm working on a fix.

The management of test->ctrl_sck isn't quite right. It appears to be closing too early and setting it to -1 has exposed it.