HTTP/3: Write static header names (#38565)

Author: JamesNK

src/Servers/Kestrel/Core/src/Internal/Http3/Http3FrameWriter.cs

@@ -311,7 +311,7 @@ public ValueTask<FlushResult> WriteResponseTrailersAsync(long streamId, HttpResp
 
                 _outgoingFrame.PrepareHeaders();
                 var buffer = _headerEncodingBuffer.GetSpan(HeaderBufferSize);
-                var done = QPackHeaderWriter.BeginEncode(_headersEnumerator, buffer, ref _headersTotalSize, out var payloadLength);
+                var done = QPackHeaderWriter.BeginEncodeHeaders(_headersEnumerator, buffer, ref _headersTotalSize, out var payloadLength);
                 FinishWritingHeaders(payloadLength, done);
             }
             // Any exception from the QPack encoder can leave the dynamic table in a corrupt state.
@@ -366,7 +366,7 @@ internal void WriteResponseHeaders(int statusCode, HttpResponseHeaders headers)
 
                 _outgoingFrame.PrepareHeaders();
                 var buffer = _headerEncodingBuffer.GetSpan(HeaderBufferSize);
-                var done = QPackHeaderWriter.BeginEncode(statusCode, _headersEnumerator, buffer, ref _headersTotalSize, out var payloadLength);
+                var done = QPackHeaderWriter.BeginEncodeHeaders(statusCode, _headersEnumerator, buffer, ref _headersTotalSize, out var payloadLength);
                 FinishWritingHeaders(payloadLength, done);
             }
             // Any exception from the QPack encoder can leave the dynamic table in a corrupt state.

src/Servers/Kestrel/Core/src/Internal/Http3/Http3HeadersEnumerator.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Net.Http.QPack;
 using System.Text;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.Extensions.Primitives;
@@ -147,7 +148,89 @@ public void Dispose()
 
     internal static int GetResponseHeaderStaticTableId(KnownHeaderType responseHeaderType)
     {
-        // Not Implemented
-        return -1;
+        // Not every header in the QPACK static table is known.
+        // These are missing from this test and the full header name is written.
+        // Missing:
+        // - link
+        // - location
+        // - strict-transport-security
+        // - x-content-type-options
+        // - x-xss-protection
+        // - content-security-policy
+        // - early-data
+        // - expect-ct
+        // - purpose
+        // - timing-allow-origin
+        // - x-forwarded-for
+        // - x-frame-options
+        switch (responseHeaderType)
+        {
+            case KnownHeaderType.Age:
+                return H3StaticTable.Age0;
+            case KnownHeaderType.ContentLength:
+                return H3StaticTable.ContentLength0;
+            case KnownHeaderType.Date:
+                return H3StaticTable.Date;
+            case KnownHeaderType.Cookie:
+                return H3StaticTable.Cookie;
+            case KnownHeaderType.ETag:
+                return H3StaticTable.ETag;
+            case KnownHeaderType.IfModifiedSince:
+                return H3StaticTable.IfModifiedSince;
+            case KnownHeaderType.IfNoneMatch:
+                return H3StaticTable.IfNoneMatch;
+            case KnownHeaderType.LastModified:
+                return H3StaticTable.LastModified;
+            case KnownHeaderType.Location:
+                return H3StaticTable.Location;
+            case KnownHeaderType.Referer:
+                return H3StaticTable.Referer;
+            case KnownHeaderType.SetCookie:
+                return H3StaticTable.SetCookie;
+            case KnownHeaderType.Method:
+                return H3StaticTable.MethodConnect;
+            case KnownHeaderType.Accept:
+                return H3StaticTable.AcceptAny;
+            case KnownHeaderType.AcceptEncoding:
+                return H3StaticTable.AcceptEncodingGzipDeflateBr;
+            case KnownHeaderType.AcceptRanges:
+                return H3StaticTable.AcceptRangesBytes;
+            case KnownHeaderType.AccessControlAllowHeaders:
+                return H3StaticTable.AccessControlAllowHeadersCacheControl;
+            case KnownHeaderType.AccessControlAllowOrigin:
+                return H3StaticTable.AccessControlAllowOriginAny;
+            case KnownHeaderType.CacheControl:
+                return H3StaticTable.CacheControlMaxAge0;
+            case KnownHeaderType.ContentEncoding:
+                return H3StaticTable.ContentEncodingBr;
+            case KnownHeaderType.ContentType:
+                return H3StaticTable.ContentTypeApplicationDnsMessage;
+            case KnownHeaderType.Range:
+                return H3StaticTable.RangeBytes0ToAll;
+            case KnownHeaderType.Vary:
+                return H3StaticTable.VaryAcceptEncoding;
+            case KnownHeaderType.AcceptLanguage:
+                return H3StaticTable.AcceptLanguage;
+            case KnownHeaderType.AccessControlAllowCredentials:
+                return H3StaticTable.AccessControlAllowCredentials;
+            case KnownHeaderType.AccessControlAllowMethods:
+                return H3StaticTable.AccessControlAllowMethodsGet;
+            case KnownHeaderType.AltSvc:
+                return H3StaticTable.AltSvcClear;
+            case KnownHeaderType.Authorization:
+                return H3StaticTable.Authorization;
+            case KnownHeaderType.IfRange:
+                return H3StaticTable.IfRange;
+            case KnownHeaderType.Origin:
+                return H3StaticTable.Origin;
+            case KnownHeaderType.Server:
+                return H3StaticTable.Server;
+            case KnownHeaderType.UpgradeInsecureRequests:
+                return H3StaticTable.UpgradeInsecureRequests1;
+            case KnownHeaderType.UserAgent:
+                return H3StaticTable.UserAgent;
+            default:
+                return -1;
+        }
     }
 }

src/Servers/Kestrel/Core/src/Internal/Http3/Http3Stream.cs

@@ -640,7 +640,7 @@ private async Task ProcessHeadersFrameAsync<TContext>(IHttpApplication<TContext>
 
         try
         {
-            QPackDecoder.Decode(payload, handler: this);
+            QPackDecoder.Decode(payload, endHeaders: true, handler: this);
             QPackDecoder.Reset();
         }
         catch (QPackDecodingException ex)

src/Servers/Kestrel/Core/src/Internal/Http3/QPackHeaderWriter.cs

@@ -4,12 +4,13 @@
 using System;
 using System.Diagnostics;
 using System.Net.Http.QPack;
+using System.Text;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http3;
 
 internal static class QPackHeaderWriter
 {
-    public static bool BeginEncode(Http3HeadersEnumerator enumerator, Span<byte> buffer, ref int totalHeaderSize, out int length)
+    public static bool BeginEncodeHeaders(Http3HeadersEnumerator enumerator, Span<byte> buffer, ref int totalHeaderSize, out int length)
     {
         bool hasValue = enumerator.MoveNext();
         Debug.Assert(hasValue == true);
@@ -24,40 +25,47 @@ public static bool BeginEncode(Http3HeadersEnumerator enumerator, Span<byte> buf
         return doneEncode;
     }
 
-    public static bool BeginEncode(int statusCode, Http3HeadersEnumerator enumerator, Span<byte> buffer, ref int totalHeaderSize, out int length)
+    public static bool BeginEncodeHeaders(int statusCode, Http3HeadersEnumerator headersEnumerator, Span<byte> buffer, ref int totalHeaderSize, out int length)
     {
-        bool hasValue = enumerator.MoveNext();
-        Debug.Assert(hasValue == true);
+        length = 0;
 
         // https://quicwg.org/base-drafts/draft-ietf-quic-qpack.html#header-prefix
         buffer[0] = 0;
         buffer[1] = 0;
 
         int statusCodeLength = EncodeStatusCode(statusCode, buffer.Slice(2));
         totalHeaderSize += 42; // name (:status) + value (xxx) + overhead (32)
+        length += statusCodeLength + 2;
 
-        bool done = Encode(enumerator, buffer.Slice(statusCodeLength + 2), throwIfNoneEncoded: false, ref totalHeaderSize, out int headersLength);
-        length = statusCodeLength + headersLength + 2;
+        if (!headersEnumerator.MoveNext())
+        {
+            return true;
+        }
+
+        bool done = Encode(headersEnumerator, buffer.Slice(statusCodeLength + 2), throwIfNoneEncoded: false, ref totalHeaderSize, out int headersLength);
+        length += headersLength;
 
         return done;
     }
 
-    public static bool Encode(Http3HeadersEnumerator enumerator, Span<byte> buffer, ref int totalHeaderSize, out int length)
+    public static bool Encode(Http3HeadersEnumerator headersEnumerator, Span<byte> buffer, ref int totalHeaderSize, out int length)
     {
-        return Encode(enumerator, buffer, throwIfNoneEncoded: true, ref totalHeaderSize, out length);
+        return Encode(headersEnumerator, buffer, throwIfNoneEncoded: true, ref totalHeaderSize, out length);
     }
 
-    private static bool Encode(Http3HeadersEnumerator enumerator, Span<byte> buffer, bool throwIfNoneEncoded, ref int totalHeaderSize, out int length)
+    private static bool Encode(Http3HeadersEnumerator headersEnumerator, Span<byte> buffer, bool throwIfNoneEncoded, ref int totalHeaderSize, out int length)
     {
         length = 0;
 
         do
         {
-            var current = enumerator.Current;
-            var valueEncoding = ReferenceEquals(enumerator.EncodingSelector, KestrelServerOptions.DefaultHeaderEncodingSelector)
-                ? null : enumerator.EncodingSelector(current.Key);
+            var staticTableId = headersEnumerator.QPackStaticTableId;
+            var name = headersEnumerator.Current.Key;
+            var value = headersEnumerator.Current.Value;
+            var valueEncoding = ReferenceEquals(headersEnumerator.EncodingSelector, KestrelServerOptions.DefaultHeaderEncodingSelector)
+                ? null : headersEnumerator.EncodingSelector(name);
 
-            if (!QPackEncoder.EncodeLiteralHeaderFieldWithoutNameReference(current.Key, current.Value, valueEncoding, buffer.Slice(length), out int headerLength))
+            if (!EncodeHeader(buffer.Slice(length), staticTableId, name, value, valueEncoding, out var headerLength))
             {
                 if (length == 0 && throwIfNoneEncoded)
                 {
@@ -67,13 +75,20 @@ private static bool Encode(Http3HeadersEnumerator enumerator, Span<byte> buffer,
             }
 
             // https://quicwg.org/base-drafts/draft-ietf-quic-http.html#section-4.1.1.3
-            totalHeaderSize += HeaderField.GetLength(current.Key.Length, current.Value.Length);
+            totalHeaderSize += HeaderField.GetLength(name.Length, value.Length);
             length += headerLength;
-        } while (enumerator.MoveNext());
+        } while (headersEnumerator.MoveNext());
 
         return true;
     }
 
+    private static bool EncodeHeader(Span<byte> buffer, int staticTableId, string name, string value, Encoding? valueEncoding, out int headerLength)
+    {
+        return staticTableId == -1
+            ? QPackEncoder.EncodeLiteralHeaderFieldWithoutNameReference(name, value, valueEncoding, buffer, out headerLength)
+            : QPackEncoder.EncodeLiteralHeaderFieldWithStaticNameReference(staticTableId, value, valueEncoding, buffer, out headerLength);
+    }
+
     private static int EncodeStatusCode(int statusCode, Span<byte> buffer)
     {
         switch (statusCode)