Copy-buffer settings do not reach the HTTP/1 header-rewriting path

Abierto
  • ¿Algo no está bien?
#39 0 comentarios 0 reacciones 0 asignados Ver en GitHub

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Evaluación

Dificultad
4/5
Tiempo estimado
3-5 días
Aptitud para principiantes
48/100
Tipo de issue
Nueva funcionalidad
Claridad
Bastante claro
Estado de actividad
Tranquilo
Stack tecnológico
rust
Área
backend, networking

Línea de trabajo

Empieza en src/http_proxy.rs, en read_header_block, copy_exact, las copias de tunnel/read-to-close y las asignaciones del carry-buffer. Sigue cómo la configuración direccional de #36 llega a los rewrite pumps, manteniendo separados los límites del parser del dimensionamiento de las copias; revisa también #37 antes de elegir un enfoque. Se considera terminado cuando las rutas de rewrite respetan los tamaños de copia configurados, los límites del parser permanecen fijos y se actualiza la documentación o justificación de la memoria por conexión.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

Problem

The readBufferSize / clientReadBufferSize / upstreamReadBufferSize settings introduced in #36 govern the plain proxying path only. A route that injects HTTP headers — sourceAddressHeader: 'xForwardedFor', or forwardFingerprint: 'ja3'|'ja4' under any mode other than proxyProtocolV2 — takes http_proxy::proxy_http1_rewriting instead, which sizes its own reads:

  • read_header_block: [0u8; 4096] (src/http_proxy.rs:36)
  • copy_exact body copies: [0u8; 8192] (src/http_proxy.rs:351)
  • tunnel / read-to-close responses: unsized tokio::io::copy
  • carry buffers: Vec::with_capacity(2048)

So clientReadBufferSize: 1024 is honored on a PROXY-protocol route and silently ignored on an xForwardedFor route on the same proxy.

Impact today is bounded: the new default (8192) equals what the body copies already use, so only a raised or lowered value is a no-op, and the primary high-connection-count target (MQTT on 8883) uses PROXY protocol and takes the plain path. #36 narrowed the README and doc comments to say so rather than leaving the proxy-wide claim standing, which is why this is a follow-up rather than a blocker there.

What to do

Thread the directional sizes through the rewrite pumps, keeping two concerns separate — they are currently conflated by using one constant for both:

  • Parser bounds (how much header may be buffered before erroring) are a safety limit and should stay pinned to MAX_HEADER_SIZE / MAX_CHUNK_LINE, not follow a user-tunable copy size. A 512-byte readBufferSize must not shrink the allowed header block.
  • Copy sizing (body copies, tunnels, read-to-close) is the memory-vs-syscall trade the config is actually for, and should follow the configured per-direction size.

Note the per-connection memory shape differs on this path: the rewriting pump holds a carry Vec plus its read buffers per direction, so the (client + upstream) × connections formula from #36 will need restating for these routes once they are tunable.

Alternative

If threading them through proves to muddy the framing logic, the other honest resolution is to leave these routes fixed and keep the documentation scoped as it is now — in which case close this issue with that rationale recorded. Worth deciding rather than leaving the asymmetry undocumented in the code.

Interacts with #37 (pooling the copy buffers), which will rework the plain path's buffer lifecycle and may make a shared abstraction available to both paths.

Lenguaje dominante
Rust
Estrellas
1
Forks
0
Merge medio
19 h 12 min
PR fusionados (30 d)
13

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