6543 HTTP/2 header continuation

nima/http2/http2/src/main/java/io/helidon/nima/http2/Http2ConnectionWriter.java

@@ -74,19 +74,62 @@ public int writeHeaders(Http2Headers headers, int streamId, Http2Flag.HeaderFlag
         // we must enforce parallelism of exactly 1, to make sure the dynamic table is updated
         // and then immediately written
 
+        int maxFrameSize = flowControl.maxFrameSize();
+
         return withStreamLock(() -> {
             int written = 0;
             headerBuffer.clear();
             headers.write(outboundDynamicTable, responseHuffman, headerBuffer);
-            Http2FrameHeader frameHeader = Http2FrameHeader.create(headerBuffer.available(),
-                                                                   Http2FrameTypes.HEADERS,
-                                                                   flags,
-                                                                   streamId);
+
+            // Fast path when headers fits within the SETTINGS_MAX_FRAME_SIZE
+            if (headerBuffer.available() <= maxFrameSize) {
+                Http2FrameHeader frameHeader = Http2FrameHeader.create(headerBuffer.available(),
+                        Http2FrameTypes.HEADERS,
+                        flags,
+                        streamId);
+                written += frameHeader.length();
+                written += Http2FrameHeader.LENGTH;
+
+                noLockWrite(new Http2FrameData(frameHeader, headerBuffer));
+                return written;
+            }
+
+            // Split header frame to smaller continuation frames RFC 9113 §6.10
+            BufferData[] fragments = Http2Headers.split(headerBuffer, maxFrameSize);
+
+            // First header fragment
+            BufferData fragment = fragments[0];
+            Http2FrameHeader frameHeader;
+            frameHeader = Http2FrameHeader.create(fragment.available(),
+                    Http2FrameTypes.HEADERS,
+                    Http2Flag.HeaderFlags.create(0),
+                    streamId);
             written += frameHeader.length();
             written += Http2FrameHeader.LENGTH;
+            noLockWrite(new Http2FrameData(frameHeader, fragment));
+
+            // Header continuation fragments in the middle
+            for (int i = 1; i < fragments.length; i++) {
+                fragment = fragments[i];
+                frameHeader = Http2FrameHeader.create(fragment.available(),
+                        Http2FrameTypes.CONTINUATION,
+                        Http2Flag.ContinuationFlags.create(0),
+                        streamId);
+                written += frameHeader.length();
+                written += Http2FrameHeader.LENGTH;
+                noLockWrite(new Http2FrameData(frameHeader, fragment));
+            }
 
-            noLockWrite(new Http2FrameData(frameHeader, headerBuffer));
-
+            // Last header continuation fragment
+            fragment = fragments[fragments.length - 1];
+            frameHeader = Http2FrameHeader.create(fragment.available(),
+                    Http2FrameTypes.CONTINUATION,
+                    // Last fragment needs to indicate the end of headers
+                    Http2Flag.ContinuationFlags.create(flags.value() | Http2Flag.END_OF_HEADERS),
+                    streamId);
+            written += frameHeader.length();
+            written += Http2FrameHeader.LENGTH;
+            noLockWrite(new Http2FrameData(frameHeader, fragment));
             return written;
         });
     }
@@ -104,17 +147,8 @@ public int writeHeaders(Http2Headers headers,
         return withStreamLock(() -> {
             int bytesWritten = 0;
 
-            headerBuffer.clear();
-            headers.write(outboundDynamicTable, responseHuffman, headerBuffer);
-            bytesWritten += headerBuffer.available();
-
-            Http2FrameHeader frameHeader = Http2FrameHeader.create(headerBuffer.available(),
-                                                                   Http2FrameTypes.HEADERS,
-                                                                   flags,
-                                                                   streamId);
-            bytesWritten += Http2FrameHeader.LENGTH;
+            bytesWritten += writeHeaders(headers, streamId, flags, flowControl);
 
-            noLockWrite(new Http2FrameData(frameHeader, headerBuffer));
             writeData(dataFrame, flowControl);
             bytesWritten += Http2FrameHeader.LENGTH;
             bytesWritten += dataFrame.header().length();

nima/http2/http2/src/main/java/io/helidon/nima/http2/Http2ErrorCode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2023 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -96,7 +96,12 @@ public enum Http2ErrorCode {
      * The endpoint requires that HTTP/1.1 be used
      * instead of HTTP/2.
      */
-    HTTP_1_1_REQUIRED(0xd);
+    HTTP_1_1_REQUIRED(0xd),
+    /**
+     * Request header fields are too large.
+     * RFC6585
+     */
+    REQUEST_HEADER_FIELDS_TOO_LARGE(431);
 
     private static final Map<Integer, Http2ErrorCode> BY_CODE;
 

nima/http2/http2/src/main/java/io/helidon/nima/http2/Http2Headers.java

@@ -440,6 +440,27 @@ public void write(DynamicTable table, Http2HuffmanEncoder huffman, BufferData gr
         }
     }
 
+    static BufferData[] split(BufferData bufferData, int size) {
+        int length = bufferData.available();
+        if (length <= size) {
+            return new BufferData[]{bufferData};
+        }
+
+        int lastFragmentSize = length % size;
+        // Avoid creating 0 length last fragment
+        int allFrames = (length / size) + (lastFragmentSize != 0 ? 1 : 0);
+        BufferData[] result = new BufferData[allFrames];
+
+        for (int i = 0; i < allFrames; i++) {
+            boolean lastFrame = (allFrames == i + 1);
+            byte[] frag = new byte[lastFrame ? (lastFragmentSize != 0 ? lastFragmentSize : size) : size];
+            bufferData.read(frag);
+            result[i] = BufferData.create(frag);
+        }
+
+        return result;
+    }
+
     private static Http2Headers create(ServerRequestHeaders httpHeaders, PseudoHeaders pseudoHeaders) {
         return new Http2Headers(httpHeaders, pseudoHeaders);
     }

nima/http2/http2/src/test/java/io/helidon/nima/http2/MaxFrameSizeSplitTest.java

@@ -24,6 +24,7 @@
 import io.helidon.logging.common.LogConfig;
 
 import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
@@ -65,6 +66,15 @@ private static Stream<SplitTest> splitMultiple() {
         );
     }
 
+    @Test
+    void splitHeaders() {
+        BufferData bf = BufferData.create("This is so long text!");
+        BufferData[] split = Http2Headers.split(bf, 12);
+        assertThat(split.length, is(2));
+        assertThat(split[0].available(), is(12));
+        assertThat(split[1].available(), is(9));
+    }
+
     @ParameterizedTest
     @MethodSource
     void splitMultiple(SplitTest args) {

nima/http2/webserver/src/main/java/io/helidon/nima/http2/webserver/Http2Config.java

@@ -42,11 +42,11 @@ public interface Http2Config {
     /**
      * The maximum field section size that the sender is prepared to accept in bytes.
      * See RFC 9113 section 6.5.2 for details.
-     * Default is maximal unsigned int.
+     * Default is 8192.
      *
      * @return maximal header list size in bytes
      */
-    @ConfiguredOption("0xFFFFFFFFL")
+    @ConfiguredOption("8192")
     long maxHeaderListSize();
 
     /**

nima/http2/webserver/src/main/java/io/helidon/nima/http2/webserver/Http2Connection.java

@@ -400,11 +400,10 @@ private void readFrame() {
 
     private void doContinuation() {
         Http2Flag.ContinuationFlags flags = frameHeader.flags(Http2FrameTypes.CONTINUATION);
-        List<Http2FrameData> continuationData = stream(frameHeader.streamId()).contData();
-        if (continuationData.isEmpty()) {
-            throw new Http2Exception(Http2ErrorCode.PROTOCOL, "Received continuation without headers.");
-        }
-        continuationData.add(new Http2FrameData(frameHeader, inProgressFrame()));
+
+        stream(frameHeader.streamId())
+                .addContinuation(new Http2FrameData(frameHeader, inProgressFrame()));
+
         if (flags.endOfHeaders()) {
             state = State.HEADERS;
         } else {
@@ -544,9 +543,7 @@ private void doHeaders() {
         // first frame, expecting continuation
         if (frameHeader.type() == Http2FrameType.HEADERS && !frameHeader.flags(Http2FrameTypes.HEADERS).endOfHeaders()) {
             // this needs to retain the data until we receive last continuation, cannot use the same data
-            streamContext.contData().clear();
-            streamContext.contData().add(new Http2FrameData(frameHeader, inProgressFrame().copy()));
-            streamContext.continuationHeader = frameHeader;
+            streamContext.addHeadersToBeContinued(frameHeader, inProgressFrame().copy());
             this.continuationExpectedStreamId = streamId;
             this.state = State.READ_FRAME;
             return;
@@ -559,14 +556,12 @@ private void doHeaders() {
 
         if (frameHeader.type() == Http2FrameType.CONTINUATION) {
             // end of continuations with header frames
-            List<Http2FrameData> frames = streamContext.contData();
             headers = Http2Headers.create(stream,
                                           requestDynamicTable,
                                           requestHuffman,
-                                          frames.toArray(new Http2FrameData[0]));
-            endOfStream = streamContext.continuationHeader.flags(Http2FrameTypes.HEADERS).endOfStream();
-            frames.clear();
-            streamContext.continuationHeader = null;
+                                          streamContext.contData());
+            endOfStream = streamContext.contHeader().flags(Http2FrameTypes.HEADERS).endOfStream();
+            streamContext.clearContinuations();
             continuationExpectedStreamId = 0;
         } else {
             endOfStream = frameHeader.flags(Http2FrameTypes.HEADERS).endOfStream();
@@ -716,6 +711,7 @@ private StreamContext stream(int streamId) {
             }
 
             streamContext = new StreamContext(streamId,
+                                              http2Config.maxHeaderListSize(),
                                               new Http2Stream(ctx,
                                                               routing,
                                                               http2Config,
@@ -788,26 +784,58 @@ public void run() {
 
     private static class StreamContext {
         private final List<Http2FrameData> continuationData = new ArrayList<>();
+        private final long maxHeaderListSize;
         private final int streamId;
         private final Http2Stream stream;
+        private long headerListSize = 0;
 
         private Http2FrameHeader continuationHeader;
 
-        StreamContext(int streamId, Http2Stream stream) {
+        StreamContext(int streamId, long maxHeaderListSize, Http2Stream stream) {
             this.streamId = streamId;
+            this.maxHeaderListSize = maxHeaderListSize;
             this.stream = stream;
         }
 
         public Http2Stream stream() {
             return stream;
         }
 
-        public Http2FrameHeader contHeader() {
+        Http2FrameData[] contData() {
+            return continuationData.toArray(new Http2FrameData[0]);
+        }
+
+        Http2FrameHeader contHeader() {
             return continuationHeader;
         }
 
-        public List<Http2FrameData> contData() {
-            return continuationData;
+        void addContinuation(Http2FrameData frameData) {
+            if (continuationData.isEmpty()) {
+                throw new Http2Exception(Http2ErrorCode.PROTOCOL, "Received continuation without headers.");
+            }
+            this.continuationData.add(frameData);
+            addAndValidateHeaderListSize(frameData.header().length());
+        }
+
+        void addHeadersToBeContinued(Http2FrameHeader frameHeader,  BufferData bufferData) {
+            clearContinuations();
+            continuationHeader = frameHeader;
+            this.continuationData.add(new Http2FrameData(frameHeader, bufferData));
+            addAndValidateHeaderListSize(frameHeader.length());
+        }
+
+        private void addAndValidateHeaderListSize(int headerSizeIncrement){
+            // Check MAX_HEADER_LIST_SIZE
+            headerListSize += headerSizeIncrement;
+            if (headerListSize > maxHeaderListSize){
+                throw new Http2Exception(Http2ErrorCode.REQUEST_HEADER_FIELDS_TOO_LARGE,
+                        "Request Header Fields Too Large");
+            }
+        }
+
+        private void clearContinuations() {
+            continuationData.clear();
+            headerListSize = 0;
         }
     }
 }