nghttp2_hd: Clear reference set with index 0

hdtest/deflatehd.c

@@ -366,7 +366,8 @@ int main(int argc, char **argv)
       break;
     }
   }
-  nghttp2_hd_deflate_init2(&deflater, config.side, config.deflate_table_size);
+  nghttp2_hd_deflate_init2(&deflater, config.side, config.deflate_table_size,
+                           0);
   nghttp2_hd_change_table_size(&deflater, config.table_size);
   if(config.http1text) {
     perform_from_http1text(&deflater);

lib/nghttp2_hd.c

@@ -246,12 +246,14 @@ static void nghttp2_hd_ringbuf_pop_back(nghttp2_hd_ringbuf *ringbuf)
 static int nghttp2_hd_context_init(nghttp2_hd_context *context,
                                    nghttp2_hd_role role,
                                    nghttp2_hd_side side,
-                                   size_t deflate_hd_table_bufsize_max)
+                                   size_t deflate_hd_table_bufsize_max,
+                                   uint8_t no_refset)
 {
   int rv;
   context->role = role;
   context->side = side;
   context->bad = 0;
+  context->no_refset = no_refset;
   context->hd_table_bufsize_max = NGHTTP2_HD_DEFAULT_MAX_BUFFER_SIZE;
   rv = nghttp2_hd_ringbuf_init
     (&context->hd_table,
@@ -302,20 +304,24 @@ static int nghttp2_hd_context_init(nghttp2_hd_context *context,
 int nghttp2_hd_deflate_init(nghttp2_hd_context *deflater, nghttp2_hd_side side)
 {
   return nghttp2_hd_context_init(deflater, NGHTTP2_HD_ROLE_DEFLATE, side,
-                                 NGHTTP2_HD_DEFAULT_MAX_DEFLATE_BUFFER_SIZE);
+                                 NGHTTP2_HD_DEFAULT_MAX_DEFLATE_BUFFER_SIZE,
+                                 0);
 }
 
 int nghttp2_hd_deflate_init2(nghttp2_hd_context *deflater,
                              nghttp2_hd_side side,
-                             size_t deflate_hd_table_bufsize_max)
+                             size_t deflate_hd_table_bufsize_max,
+                             uint8_t no_refset)
 {
   return nghttp2_hd_context_init(deflater, NGHTTP2_HD_ROLE_DEFLATE, side,
-                                 deflate_hd_table_bufsize_max);
+                                 deflate_hd_table_bufsize_max,
+                                 no_refset);
 }
 
 int nghttp2_hd_inflate_init(nghttp2_hd_context *inflater, nghttp2_hd_side side)
 {
-  return nghttp2_hd_context_init(inflater, NGHTTP2_HD_ROLE_INFLATE, side, 0);
+  return nghttp2_hd_context_init(inflater, NGHTTP2_HD_ROLE_INFLATE, side, 0,
+                                 0);
 }
 
 static void nghttp2_hd_context_free(nghttp2_hd_context *context)
@@ -574,6 +580,19 @@ static  uint8_t* decode_length(ssize_t *res, uint8_t *in, uint8_t *last,
   }
 }
 
+static int emit_indexed0(uint8_t **buf_ptr, size_t *buflen_ptr,
+                         size_t *offset_ptr)
+{
+  int rv;
+  rv = ensure_write_buffer(buf_ptr, buflen_ptr, *offset_ptr, 1);
+  if(rv != 0) {
+    return rv;
+  }
+  *(*buf_ptr + *offset_ptr) = 0x80u;
+  ++*offset_ptr;
+  return 0;
+}
+
 static int emit_indexed_block(uint8_t **buf_ptr, size_t *buflen_ptr,
                               size_t *offset_ptr, size_t index)
 {
@@ -894,6 +913,15 @@ int nghttp2_hd_change_table_size(nghttp2_hd_context *context,
   return 0;
 }
 
+static void clear_refset(nghttp2_hd_context *context)
+{
+  size_t i;
+  for(i = 0; i < context->hd_table.len; ++i) {
+    nghttp2_hd_entry *ent = nghttp2_hd_ringbuf_get(&context->hd_table, i);
+    ent->flags &= ~NGHTTP2_HD_FLAG_REFSET;
+  }
+}
+
 static int check_index_range(nghttp2_hd_context *context, size_t index)
 {
   return index < context->hd_table.len + STATIC_TABLE_LENGTH;
@@ -1066,6 +1094,13 @@ ssize_t nghttp2_hd_deflate_hd(nghttp2_hd_context *deflater,
     return NGHTTP2_ERR_HEADER_COMP;
   }
   offset = nv_offset;
+  if(deflater->no_refset) {
+    rv = emit_indexed0(buf_ptr, buflen_ptr, &offset);
+    if(rv != 0) {
+      goto fail;
+    }
+    clear_refset(deflater);
+  }
   for(i = 0; i < nvlen; ++i) {
     rv = deflate_nv(deflater, buf_ptr, buflen_ptr, &offset, &nv[i]);
     if(rv != 0) {
@@ -1136,10 +1171,14 @@ ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_context *inflater,
       ssize_t index;
       nghttp2_hd_entry *ent;
       in = decode_length(&index, in, last, 7);
-      if(index <= 0) {
+      if(index < 0) {
         rv = NGHTTP2_ERR_HEADER_COMP;
         goto fail;
       }
+      if(index == 0) {
+        clear_refset(inflater);
+        continue;
+      }
       --index;
       if(!check_index_range(inflater, index)) {
         rv = NGHTTP2_ERR_HEADER_COMP;

lib/nghttp2_hd.h

@@ -123,6 +123,9 @@ typedef struct {
      further invocation of inflate/deflate will fail with
      NGHTTP2_ERR_HEADER_COMP. */
   uint8_t bad;
+  /* Set to this nonzero to clear reference set on each deflation each
+     time. */
+  uint8_t no_refset;
   /* Role of this context; deflate or infalte */
   nghttp2_hd_role role;
   /* NGHTTP2_HD_SIDE_REQUEST for processing request, otherwise
@@ -179,6 +182,9 @@ int nghttp2_hd_deflate_init(nghttp2_hd_context *deflater,
  * for header table even if the larger value is specified later in
  * nghttp2_hd_change_table_size().
  *
+ * If nonzero is given in the |no_refset|, the encoder first clears
+ * the reference set each time on deflation.
+ *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
@@ -187,7 +193,8 @@ int nghttp2_hd_deflate_init(nghttp2_hd_context *deflater,
  */
 int nghttp2_hd_deflate_init2(nghttp2_hd_context *deflater,
                              nghttp2_hd_side side,
-                             size_t deflate_hd_table_bufsize_max);
+                             size_t deflate_hd_table_bufsize_max,
+                             uint8_t no_refset);
 
 /*
  * Initializes |inflater| for inflating name/values pairs.

tests/main.c

@@ -233,6 +233,8 @@ int main(int argc, char* argv[])
                    test_nghttp2_hd_deflate_common_header_eviction) ||
       !CU_add_test(pSuite, "hd_deflate_deflate_buffer",
                    test_nghttp2_hd_deflate_deflate_buffer) ||
+      !CU_add_test(pSuite, "hd_deflate_clear_refset",
+                   test_nghttp2_hd_deflate_clear_refset) ||
       !CU_add_test(pSuite, "hd_inflate_indname_noinc",
                    test_nghttp2_hd_inflate_indname_noinc) ||
       !CU_add_test(pSuite, "hd_inflate_indname_inc",

tests/nghttp2_hd_test.c

@@ -278,7 +278,7 @@ void test_nghttp2_hd_deflate_deflate_buffer(void)
   /* Check the case where entry from static table is inserted to
      dynamic header table. And it is out of deflate header table
      size. */
-  nghttp2_hd_deflate_init2(&deflater, NGHTTP2_HD_SIDE_REQUEST, 32);
+  nghttp2_hd_deflate_init2(&deflater, NGHTTP2_HD_SIDE_REQUEST, 32, 0);
   nghttp2_hd_inflate_init(&inflater, NGHTTP2_HD_SIDE_REQUEST);
   blocklen = nghttp2_hd_deflate_hd(&deflater, &buf, &buflen, 0,
                                    nva4, ARRLEN(nva4));
@@ -310,8 +310,7 @@ void test_nghttp2_hd_deflate_deflate_buffer(void)
   nghttp2_hd_inflate_free(&inflater);
 
   /* 156 buffer size can hold all headers in deflate region */
-  nghttp2_hd_deflate_init2(&deflater, NGHTTP2_HD_SIDE_REQUEST,
-                           156);
+  nghttp2_hd_deflate_init2(&deflater, NGHTTP2_HD_SIDE_REQUEST, 156, 0);
   blocklen = nghttp2_hd_deflate_hd(&deflater, &buf, &buflen, 0,
                                    nva1, ARRLEN(nva1));
   CU_ASSERT(blocklen > 0);
@@ -345,8 +344,7 @@ void test_nghttp2_hd_deflate_deflate_buffer(void)
   nghttp2_hd_deflate_free(&deflater);
 
   /* Check more complex use case */
-  nghttp2_hd_deflate_init2(&deflater, NGHTTP2_HD_SIDE_REQUEST,
-                           155);
+  nghttp2_hd_deflate_init2(&deflater, NGHTTP2_HD_SIDE_REQUEST, 155, 0);
   nghttp2_hd_inflate_init(&inflater, NGHTTP2_HD_SIDE_REQUEST);
   blocklen = nghttp2_hd_deflate_hd(&deflater, &buf, &buflen, 0,
                                    nva1, ARRLEN(nva1));
@@ -439,6 +437,43 @@ void test_nghttp2_hd_deflate_deflate_buffer(void)
 
 }
 
+void test_nghttp2_hd_deflate_clear_refset(void)
+{
+  nghttp2_hd_context deflater, inflater;
+  uint8_t *buf = NULL;
+  size_t buflen = 0;
+  ssize_t blocklen;
+  nghttp2_nv nv[] = {
+    MAKE_NV(":path", "/"),
+    MAKE_NV(":scheme", "http")
+  };
+  nghttp2_nv *resnva;
+  ssize_t nvlen;
+  size_t i;
+
+  nghttp2_hd_deflate_init2(&deflater, NGHTTP2_HD_SIDE_REQUEST,
+                           NGHTTP2_HD_DEFAULT_MAX_DEFLATE_BUFFER_SIZE, 1);
+  nghttp2_hd_inflate_init(&inflater, NGHTTP2_HD_SIDE_REQUEST);
+
+  for(i = 0; i < 2; ++i) {
+    blocklen = nghttp2_hd_deflate_hd(&deflater, &buf, &buflen, 0,
+                                     nv, ARRLEN(nv));
+    CU_ASSERT(blocklen > 1);
+
+    nvlen = nghttp2_hd_inflate_hd(&inflater, &resnva, buf, blocklen);
+    CU_ASSERT(ARRLEN(nv) == nvlen);
+    nghttp2_nv_array_sort(resnva, ARRLEN(nv));
+    assert_nv_equal(nv, resnva, ARRLEN(nv));
+
+    nghttp2_hd_end_headers(&inflater);
+    nghttp2_nv_array_del(resnva);
+  }
+
+  free(buf);
+  nghttp2_hd_inflate_free(&inflater);
+  nghttp2_hd_deflate_free(&deflater);
+}
+
 void test_nghttp2_hd_inflate_indname_noinc(void)
 {
   nghttp2_hd_context inflater;

tests/nghttp2_hd_test.h

@@ -29,6 +29,7 @@ void test_nghttp2_hd_deflate(void);
 void test_nghttp2_hd_deflate_same_indexed_repr(void);
 void test_nghttp2_hd_deflate_common_header_eviction(void);
 void test_nghttp2_hd_deflate_deflate_buffer(void);
+void test_nghttp2_hd_deflate_clear_refset(void);
 void test_nghttp2_hd_inflate_indname_noinc(void);
 void test_nghttp2_hd_inflate_indname_inc(void);
 void test_nghttp2_hd_inflate_indname_inc_eviction(void);