From 2aa84019c7044b1cbd5493e516a09df33d1a230a Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Thu, 22 May 2014 21:36:12 +0900
Subject: [PATCH] Define constants for ALTSVC frame parsing

---
 lib/nghttp2_frame.c   |  3 +--
 lib/nghttp2_frame.h   | 10 ++++++++++
 lib/nghttp2_session.c |  6 +++---
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/lib/nghttp2_frame.c b/lib/nghttp2_frame.c
index 59f78115..1595c49a 100644
--- a/lib/nghttp2_frame.c
+++ b/lib/nghttp2_frame.c
@@ -196,8 +196,7 @@ void nghttp2_frame_altsvc_init(nghttp2_altsvc *frame, int32_t stream_id,
 {
   size_t payloadlen;
 
-  /* 8 for Max-Age, Port, Reserved and PID_LEN.  1 for HOST_LEN. */
-  payloadlen = 8 + protocol_id_len + 1 + host_len + origin_len;
+  payloadlen = NGHTTP2_ALTSVC_MINLEN + protocol_id_len + host_len + origin_len;
 
   frame_set_hd(&frame->hd, payloadlen, NGHTTP2_ALTSVC, NGHTTP2_FLAG_NONE,
                stream_id);
diff --git a/lib/nghttp2_frame.h b/lib/nghttp2_frame.h
index ca5ca7b6..a9f9abb2 100644
--- a/lib/nghttp2_frame.h
+++ b/lib/nghttp2_frame.h
@@ -60,6 +60,16 @@
 /* The maximum header table size in SETTINGS_HEADER_TABLE_SIZE */
 #define NGHTTP2_MAX_HEADER_TABLE_SIZE ((1u << 31) - 1)
 
+
+/* Length of fixed part in ALTSVC frame, that is the sum of fields of
+   Max-Age, Port, Reserved and PID_LEN. */
+#define NGHTTP2_ALTSVC_FIXED_PARTLEN 8
+
+/* Minimum length of ALTSVC frame.  NGHTTP2_ALTSVC_FIXED_PARTLEN +
+   HOST_LEN. */
+#define NGHTTP2_ALTSVC_MINLEN 9
+
+
 /* Category of frames. */
 typedef enum {
   /* non-DATA frame */
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 8bf399e0..6c309dbf 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -4490,7 +4490,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session,
           break;
         }
 
-        if(iframe->payloadleft < 9) {
+        if(iframe->payloadleft < NGHTTP2_ALTSVC_MINLEN) {
           busy = 1;
 
           iframe->state = NGHTTP2_IB_FRAME_SIZE_ERROR;
@@ -4499,7 +4499,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session,
         }
 
         iframe->state = NGHTTP2_IB_READ_NBYTE;
-        inbound_frame_set_mark(iframe, 8);
+        inbound_frame_set_mark(iframe, NGHTTP2_ALTSVC_FIXED_PARTLEN);
 
         break;
       case NGHTTP2_BLOCKED:
@@ -4711,7 +4711,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session,
       case NGHTTP2_ALTSVC: {
         size_t varlen;
 
-        varlen = iframe->frame.hd.length - 8;
+        varlen = iframe->frame.hd.length - NGHTTP2_ALTSVC_FIXED_PARTLEN;
 
         if(varlen > 0) {
           iframe->raw_lbuf = malloc(varlen);