feat(s2n-quic-core): add null TLS provider for testing

[camshaft]

Description of changes:

When doing performance testing, it can be helpful to disable crypto entirely in order to isolate and identify bottlenecks.

This change adds a private TLS provider that simply exchanges transport parameters over cleartext and doesn't encrypt anything. This has somewhat similar goals as the quic-disable-encryption draft, but is quite a bit simpler since it doesn't do any negotiation or handshaking.

Testing:

I added an integration test to make sure the null TLS provider negotiated with itself. I also added support for using it in the qns application to make it easier to benchmark.

$ ./target/release/s2n-quic-qns perf server --ip 192.167.1.10 --port 4433 --stats --max-throughput 1000 --tls null

$ ./target/release/s2n-quic-qns perf client --ip 192.167.1.10 --port 4433 --receive 10000000000000000000 --stats --max-throughput 1500 --tls null

Send

Send (XDP)

Receive

Receive (XDP)

Tx Rate	Rx Rate	Max Cwnd	Max Inflight	Lost Packets	Wakeups	Duration	Max RTT	Max SRTT	PTO Count	Max Pacing Rate	Max Delivery Rate
37.78Gbps       0bps    6.61MB  6.61MB  105     2586    26.874ms        2.205ms 1.198237ms      0       0bps    0bps
37.46Gbps       0bps    6.71MB  6.71MB  167     2591    26.574ms        4.069ms 2.226255ms      0       27.31Gbps       0bps
37.80Gbps       0bps    6.65MB  6.65MB  93      2613    26.81ms 2.205ms 1.206517ms      0       0bps    0bps
37.57Gbps       0bps    6.65MB  6.65MB  203     2564    26.709ms        2.331ms 1.939357ms      0       0bps    0bps
37.45Gbps       0bps    6.62MB  6.61MB  167     2533    26.588ms        3.99ms  2.262232ms      0       28.05Gbps       0bps
37.79Gbps       0bps    6.66MB  6.66MB  97      2606    26.549ms        2.213ms 1.224121ms      9       0bps    0bps
37.86Gbps       0bps    6.60MB  6.59MB  123     2520    26.723ms        2.113ms 1.186678ms      0       0bps    0bps
37.43Gbps       0bps    6.66MB  6.66MB  223     2532    26.622ms        2.374ms 1.974841ms      0       0bps    0bps
37.48Gbps       0bps    6.80MB  6.87MB  131     2611    631µs   4.03ms  2.436432ms      10      30.01Gbps       0bps
37.88Gbps       0bps    6.57MB  6.56MB  167     2649    26.725ms        2.006ms 2.214737ms      0       31.27Gbps       0bps
37.46Gbps       0bps    6.80MB  6.87MB  230     2520    26.632ms        3.282ms 2.029627ms      10      22.57Gbps       0bps
37.44Gbps       0bps    6.62MB  6.61MB  90      2484    26.694ms        3.338ms 2.040467ms      0       23.81Gbps       0bps
37.95Gbps       0bps    6.62MB  6.62MB  158     2613    26.605ms        2.325ms 1.198464ms      0       0bps    0bps
37.33Gbps       0bps    6.64MB  6.64MB  175     2544    26.707ms        3.157ms 2.409539ms      0       30.01Gbps       0bps
37.40Gbps       0bps    6.64MB  6.64MB  225     2520    26.897ms        3.257ms 2.469882ms      0       31.75Gbps       0bps
37.94Gbps       0bps    6.68MB  6.68MB  120     2581    26.613ms        2.138ms 1.203878ms      0       0bps    0bps
37.41Gbps       0bps    6.66MB  6.66MB  72      2523    26.6ms  4.13ms  1.739614ms      0       0bps    0bps
37.82Gbps       0bps    6.64MB  6.63MB  188     2539    31.497ms        4.749ms 1.683957ms      0       0bps    0bps
37.47Gbps       0bps    6.65MB  6.64MB  303     2553    26.638ms        2.613ms 1.815557ms      0       0bps    0bps
37.39Gbps       0bps    6.64MB  6.64MB  113     2516    26.51ms 4.144ms 2.179126ms      10      26.60Gbps       0bps
37.87Gbps       0bps    6.68MB  6.68MB  182     2605    26.668ms        2.175ms 1.17278ms       0       0bps    0bps

$ iperf3 -s -p 4433
-----------------------------------------------------------
Server listening on 4433 (test #1)
-----------------------------------------------------------
Accepted connection from 192.167.1.20, port 39380
[  5] local 192.167.1.10 port 4433 connected to 192.167.1.20 port 39390
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  4.82 GBytes  41.4 Gbits/sec
[  5]   1.00-2.00   sec  4.87 GBytes  41.9 Gbits/sec
[  5]   2.00-3.00   sec  4.85 GBytes  41.7 Gbits/sec
[  5]   3.00-4.00   sec  4.81 GBytes  41.3 Gbits/sec
[  5]   4.00-5.00   sec  4.85 GBytes  41.6 Gbits/sec
[  5]   5.00-6.00   sec  4.86 GBytes  41.7 Gbits/sec
[  5]   6.00-7.00   sec  4.84 GBytes  41.5 Gbits/sec
[  5]   7.00-8.00   sec  4.79 GBytes  41.2 Gbits/sec
[  5]   8.00-9.00   sec  4.73 GBytes  40.6 Gbits/sec
[  5]   9.00-10.00  sec  4.86 GBytes  41.8 Gbits/sec

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[WesleyRosenblum]

Opened #1857 to add to the CI, as discussed offline

[WesleyRosenblum]

do you think its worth a println here and in new_client_session just warning that a null TLS session has been initiated that will not perform any encryption?

[camshaft]

my worry is if we're testing the connection creation latency outside of crypto it would also affect the measurement since we're printing to the console

[camshaft]

Actually thinking about it a bit, I'll put it in the Endpoint::default() method, since that's only created at start up.

[WesleyRosenblum]

Suggested change

	eprintln!(" An s2n-quic endpoint has configured without cryptographic protections.");
	eprintln!(" This should ONLY be used for testing purposed only.");
	eprintln!(" An s2n-quic endpoint has been configured without cryptographic protections.");
	eprintln!(" This should ONLY be used for testing purposes.");