TUN-6038: Reduce buffer size used for proxying data

The buffer size was big to support a compression feature that we don't
use anymore.
As such, we can now reduce this and be more efficient with memory usage.

proxy/pool.go

@@ -1,29 +0,0 @@
-package proxy
-
-import (
-	"sync"
-)
-
-type bufferPool struct {
-	// A bufferPool must not be copied after first use.
-	// https://golang.org/pkg/sync/#Pool
-	buffers sync.Pool
-}
-
-func newBufferPool(bufferSize int) *bufferPool {
-	return &bufferPool{
-		buffers: sync.Pool{
-			New: func() interface{} {
-				return make([]byte, bufferSize)
-			},
-		},
-	}
-}
-
-func (p *bufferPool) Get() []byte {
-	return p.buffers.Get().([]byte)
-}
-
-func (p *bufferPool) Put(buf []byte) {
-	p.buffers.Put(buf)
-}

proxy/proxy.go

@@ -12,6 +12,7 @@ import (
 	"github.com/rs/zerolog"
 
 	"github.com/cloudflare/cloudflared/carrier"
+	"github.com/cloudflare/cloudflared/cfio"
 	"github.com/cloudflare/cloudflared/connection"
 	"github.com/cloudflare/cloudflared/ingress"
 	tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs"
@@ -32,7 +33,6 @@ type Proxy struct {
 	warpRouting  *ingress.WarpRoutingService
 	tags         []tunnelpogs.Tag
 	log          *zerolog.Logger
-	bufferPool   *bufferPool
 }
 
 // NewOriginProxy returns a new instance of the Proxy struct.
@@ -46,7 +46,6 @@ func NewOriginProxy(
 		ingressRules: ingressRules,
 		tags:         tags,
 		log:          log,
-		bufferPool:   newBufferPool(512 * 1024),
 	}
 	if warpRoutingEnabled {
 		proxy.warpRouting = ingress.NewWarpRoutingService()
@@ -218,11 +217,7 @@ func (p *Proxy) proxyHTTPRequest(
 		p.log.Debug().Msg("Detected Server-Side Events from Origin")
 		p.writeEventStream(w, resp.Body)
 	} else {
-		// Use CopyBuffer, because Copy only allocates a 32KiB buffer, and cross-stream
-		// compression generates dictionary on first write
-		buf := p.bufferPool.Get()
-		defer p.bufferPool.Put(buf)
-		_, _ = io.CopyBuffer(w, resp.Body, buf)
+		_, _ = cfio.Copy(w, resp.Body)
 	}
 
 	p.logOriginResponse(resp, fields)