Adjust transmission frame buffer size to support maximum payload size

lib/nghttp2_frame.h

@@ -43,18 +43,16 @@
 /* The number of bytes of frame header. */
 #define NGHTTP2_FRAME_HDLEN 8
 
-/* The maximum frame and payload length. The spec allows maximum
-   payload length up to 16383 bytes. Due to efficient buffer
-   allocation, we choose smaller buffer. Actual payload limit offsets
-   frame header and possible PAD_HIGH and PAD_LOW to ease
-   serialization and save memcopying. */
-#define NGHTTP2_MAX_FRAMELEN 8192
-#define NGHTTP2_MAX_PAYLOADLEN (NGHTTP2_MAX_FRAMELEN - NGHTTP2_FRAME_HDLEN - 2)
-
-/* The maximum length of DATA frame payload. To fit entire DATA frame
-   into 4096K buffer, we use subtract header size (8 bytes) + 2 bytes
-   padding. See nghttp2_session_pack_data(). */
-#define NGHTTP2_DATA_PAYLOAD_LENGTH (4096 - NGHTTP2_FRAME_HDLEN - 2)
+#define NGHTTP2_MAX_PAYLOADLEN 16383
+/* The one frame buffer length for tranmission.  We may use several of
+   them to support CONTINUATION.  To account for padding specifiers
+   (PAD_HIGH and PAD_LOW), we allocate extra 2 bytes, which saves
+   extra large memcopying. */
+#define NGHTTP2_FRAMEBUF_CHUNKLEN \
+  (NGHTTP2_FRAME_HDLEN + 2 + NGHTTP2_MAX_PAYLOADLEN)
+
+/* The maximum length of DATA frame payload. */
+#define NGHTTP2_DATA_PAYLOAD_LENGTH 4096
 
 /* The number of bytes for each SETTINGS entry */
 #define NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH 5

lib/nghttp2_session.c

@@ -321,12 +321,9 @@ static int nghttp2_session_new(nghttp2_session **session_ptr,
     (*session_ptr)->server = 1;
   }
 
-  /* 2 for PAD_HIGH and PAD_LOW. We have maximum 64KB of frame
-     serialization buffer for transmission */
+  /* 2 for PAD_HIGH and PAD_LOW. */
   rv = nghttp2_bufs_init3(&(*session_ptr)->aob.framebufs,
-                          NGHTTP2_MAX_FRAMELEN,
-                          (1 << 17) / NGHTTP2_MAX_FRAMELEN,
-                          (1 << 13) / NGHTTP2_MAX_FRAMELEN,
+                          NGHTTP2_FRAMEBUF_CHUNKLEN, 8, 1,
                           NGHTTP2_FRAME_HDLEN + 2);
   if(rv != 0) {
     goto fail_aob_framebuf;

tests/nghttp2_session_test.c

@@ -4659,7 +4659,7 @@ void test_nghttp2_session_pack_headers_with_padding(void)
   accumulator acc;
   my_user_data ud;
   nghttp2_session_callbacks callbacks;
-  nghttp2_nv nva[4086];
+  nghttp2_nv nva[8172];
   size_t i;
   nghttp2_priority_spec pri_spec;
 
@@ -4725,7 +4725,7 @@ void test_nghttp2_session_pack_headers_with_padding2(void)
   accumulator acc;
   my_user_data ud;
   nghttp2_session_callbacks callbacks;
-  nghttp2_nv nva[8182];
+  nghttp2_nv nva[16364];
   size_t i;
 
   for(i = 0; i < ARRLEN(nva); ++i) {