chunkloris: aioquic http/3 example-style server
on this page
part of the chunkloris per-chunk amplification survey. this page is the per-server record for aioquic HTTP/3 example-style server under http/3 data frames over quic.
at a glance
- server: aioquic HTTP/3 example-style server
aioquic 1.3.0 - runtime: python-3.12
- ecosystem: python
- concurrency model: event-loop
- parser: aioquic HTTP/3 H3Connection
- delivery granularity:
per-frame - chunk-limit helper: none exposed by the framework
- verdict: per-frame — the parser/dispatcher boundary delivers one event per protocol frame (h2 / h3 DATA frame, or ws data frame). cpu cost under paced mode b is measurable per frame.
- scaling exponent (mode a): 0.99 (wall time vs N, log-log slope across common cells)
- scaling exponent (mode b): 1.00
measurements
all cells run on a 1-vcpu docker container. cpu cost is derived from the target container’s cgroup v2 cpu.stat usage_usec delta around each cell.
| mode | N | wall (s) | server cpu % | µs / frame | basis | ok |
|---|---|---|---|---|---|---|
A-h3-bridge | 50,000 | 0.111 | 79.2 | 1.753 | server-cpu-cgroup | ✓ |
A-h3-bridge | 100,000 | 0.222 | 71.8 | 1.591 | server-cpu-cgroup | ✓ |
A-h3-bridge | 250,000 | 0.543 | 62.5 | 1.357 | server-cpu-cgroup | ✓ |
B-h3-paced-100us | 50,000 | 7.033 | 30.3 | 42.672 | server-cpu-cgroup | ✓ |
B-h3-paced-100us | 100,000 | 14.122 | 25.6 | 36.147 | server-cpu-cgroup | ✓ |
B-h3-paced-100us | 250,000 | 35.102 | 25.8 | 36.282 | server-cpu-cgroup | ✓ |
parser path — source citations
- HTTP/3 API —
?→ source
what this means
the parser/dispatcher path on this server delivers one event per protocol frame (a http/3 data frames over quic DATA frame or ws frame), so an attacker who sends a request body as N one-byte frames consumes roughly N × (mode-b µs/frame) of server cpu on a single core.
what to do today
- HTTP/3 quic stream / connection flow control is byte-level; it does not bound DATA frame count.
- consider a per-stream DATA-frame credit at the h3 dispatcher before delivering payload to the application.
reproducer
the full reproducer for this server is in the paper repo. the docker container pins aioquic HTTP/3 example-style server aioquic 1.3.0 and constrains the test container to a single cpu (--cpus=1). the prober script implements mode a (bridge-coalesced) and mode b (paced 100 µs) per the methodology section.
see the draft pdf for the full per-framework discussion.