Merge github.com:grpc/grpc into no-transport-metadata

8 files changed, 301 insertions, 91 deletions

diff --git a/src/core/transport/chttp2/hpack_encoder.c b/src/core/transport/chttp2/hpack_encoder.c
index fe03b89dc2..28d5433d15 100644
--- a/src/core/transport/chttp2/hpack_encoder.c
+++ b/src/core/transport/chttp2/hpack_encoder.c
@@ -36,8 +36,10 @@
 #include <assert.h>
 #include <string.h>
 
+#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/useful.h>
+
 #include "src/core/transport/chttp2/bin_encoder.h"
 #include "src/core/transport/chttp2/hpack_table.h"
 #include "src/core/transport/chttp2/timeout_encoding.h"
@@ -155,6 +157,18 @@ static gpr_uint8 *add_tiny_header_data(framer_state *st, size_t len) {
   return gpr_slice_buffer_tiny_add(st->output, len);
 }
 
+static void evict_entry(grpc_chttp2_hpack_compressor *c) {
+  c->tail_remote_index++;
+  GPR_ASSERT(c->tail_remote_index > 0);
+  GPR_ASSERT(c->table_size >=
+             c->table_elem_size[c->tail_remote_index % c->cap_table_elems]);
+  GPR_ASSERT(c->table_elems > 0);
+  c->table_size = (gpr_uint16)(
+      c->table_size -
+      c->table_elem_size[c->tail_remote_index % c->cap_table_elems]);
+  c->table_elems--;
+}
+
 /* add an element to the decoder table */
 static void add_elem(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem) {
   gpr_uint32 key_hash = elem->key->hash;
@@ -165,26 +179,21 @@ static void add_elem(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem) {
 
   GPR_ASSERT(elem_size < 65536);
 
+  if (elem_size > c->max_table_size) {
+    while (c->table_size > 0) {
+      evict_entry(c);
+    }
+    return;
+  }
+
   /* Reserve space for this element in the remote table: if this overflows
      the current table, drop elements until it fits, matching the decompressor
      algorithm */
-  /* TODO(ctiller): constant */
-  while (c->table_size + elem_size > 4096) {
-    c->tail_remote_index++;
-    GPR_ASSERT(c->tail_remote_index > 0);
-    GPR_ASSERT(c->table_size >=
-               c->table_elem_size[c->tail_remote_index %
-                                  GRPC_CHTTP2_HPACKC_MAX_TABLE_ELEMS]);
-    GPR_ASSERT(c->table_elems > 0);
-    c->table_size =
-        (gpr_uint16)(c->table_size -
-                     c->table_elem_size[c->tail_remote_index %
-                                        GRPC_CHTTP2_HPACKC_MAX_TABLE_ELEMS]);
-    c->table_elems--;
+  while (c->table_size + elem_size > c->max_table_size) {
+    evict_entry(c);
   }
-  GPR_ASSERT(c->table_elems < GRPC_CHTTP2_HPACKC_MAX_TABLE_ELEMS);
-  c->table_elem_size[new_index % GRPC_CHTTP2_HPACKC_MAX_TABLE_ELEMS] =
-      (gpr_uint16)elem_size;
+  GPR_ASSERT(c->table_elems < c->max_table_size);
+  c->table_elem_size[new_index % c->cap_table_elems] = (gpr_uint16)elem_size;
   c->table_size = (gpr_uint16)(c->table_size + elem_size);
   c->table_elems++;
 
@@ -330,6 +339,14 @@ static void emit_lithdr_noidx_v(grpc_chttp2_hpack_compressor *c,
   add_header_data(st, gpr_slice_ref(value_slice));
 }
 
+static void emit_advertise_table_size_change(grpc_chttp2_hpack_compressor *c,
+                                             framer_state *st) {
+  gpr_uint32 len = GRPC_CHTTP2_VARINT_LENGTH(c->max_table_size, 3);
+  GRPC_CHTTP2_WRITE_VARINT(c->max_table_size, 3, 0x20,
+                           add_tiny_header_data(st, len), len);
+  c->advertise_table_size_change = 0;
+}
+
 static gpr_uint32 dynidx(grpc_chttp2_hpack_compressor *c,
                          gpr_uint32 elem_index) {
   return 1 + GRPC_CHTTP2_LAST_STATIC_ENTRY + c->tail_remote_index +
@@ -447,8 +464,20 @@ gpr_slice grpc_chttp2_data_frame_create_empty_close(gpr_uint32 id) {
   return slice;
 }
 
+static gpr_uint32 elems_for_bytes(gpr_uint32 bytes) {
+  return (bytes + 31) / 32;
+}
+
 void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c) {
   memset(c, 0, sizeof(*c));
+  c->max_table_size = GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE;
+  c->cap_table_elems = elems_for_bytes(c->max_table_size);
+  c->max_table_elems = c->cap_table_elems;
+  c->max_usable_size = GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE;
+  c->table_elem_size =
+      gpr_malloc(sizeof(*c->table_elem_size) * c->cap_table_elems);
+  memset(c->table_elem_size, 0,
+         sizeof(*c->table_elem_size) * c->cap_table_elems);
 }
 
 void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c) {
@@ -457,6 +486,55 @@ void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c) {
     if (c->entries_keys[i]) GRPC_MDSTR_UNREF(c->entries_keys[i]);
     if (c->entries_elems[i]) GRPC_MDELEM_UNREF(c->entries_elems[i]);
   }
+  gpr_free(c->table_elem_size);
+}
+
+void grpc_chttp2_hpack_compressor_set_max_usable_size(
+    grpc_chttp2_hpack_compressor *c, gpr_uint32 max_table_size) {
+  c->max_usable_size = max_table_size;
+  grpc_chttp2_hpack_compressor_set_max_table_size(
+      c, GPR_MIN(c->max_table_size, max_table_size));
+}
+
+static void rebuild_elems(grpc_chttp2_hpack_compressor *c, gpr_uint32 new_cap) {
+  gpr_uint16 *table_elem_size = gpr_malloc(sizeof(*table_elem_size) * new_cap);
+  gpr_uint32 i;
+
+  memset(table_elem_size, 0, sizeof(*table_elem_size) * new_cap);
+  GPR_ASSERT(c->table_elems <= new_cap);
+
+  for (i = 0; i < c->table_elems; i++) {
+    gpr_uint32 ofs = c->tail_remote_index + i + 1;
+    table_elem_size[ofs % new_cap] =
+        c->table_elem_size[ofs % c->cap_table_elems];
+  }
+
+  c->cap_table_elems = new_cap;
+  gpr_free(c->table_elem_size);
+  c->table_elem_size = table_elem_size;
+}
+
+void grpc_chttp2_hpack_compressor_set_max_table_size(
+    grpc_chttp2_hpack_compressor *c, gpr_uint32 max_table_size) {
+  max_table_size = GPR_MIN(max_table_size, c->max_usable_size);
+  if (max_table_size == c->max_table_size) {
+    return;
+  }
+  while (c->table_size > 0 && c->table_size > max_table_size) {
+    evict_entry(c);
+  }
+  c->max_table_size = max_table_size;
+  c->max_table_elems = elems_for_bytes(max_table_size);
+  if (c->max_table_elems > c->cap_table_elems) {
+    rebuild_elems(c, GPR_MAX(c->max_table_elems, 2 * c->cap_table_elems));
+  } else if (c->max_table_elems < c->cap_table_elems / 3) {
+    gpr_uint32 new_cap = GPR_MAX(c->max_table_elems, 16);
+    if (new_cap != c->cap_table_elems) {
+      rebuild_elems(c, new_cap);
+    }
+  }
+  c->advertise_table_size_change = 1;
+  gpr_log(GPR_DEBUG, "set max table size from encoder to %d", max_table_size);
 }
 
 void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c,
@@ -479,6 +557,9 @@ void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c,
      slot. THIS MAY NOT BE THE SAME ELEMENT (if a decoder table slot got
      updated). After this loop, we'll do a batch unref of elements. */
   begin_frame(&st);
+  if (c->advertise_table_size_change != 0) {
+    emit_advertise_table_size_change(c, &st);
+  }
   grpc_metadata_batch_assert_ok(metadata);
   for (l = metadata->list.head; l; l = l->next) {
     hpack_enc(c, l->md, &st);
diff --git a/src/core/transport/chttp2/hpack_encoder.h b/src/core/transport/chttp2/hpack_encoder.h
index dab6f66c71..a3600436e9 100644
--- a/src/core/transport/chttp2/hpack_encoder.h
+++ b/src/core/transport/chttp2/hpack_encoder.h
@@ -43,14 +43,26 @@
 
 #define GRPC_CHTTP2_HPACKC_NUM_FILTERS 256
 #define GRPC_CHTTP2_HPACKC_NUM_VALUES 256
-#define GRPC_CHTTP2_HPACKC_MAX_TABLE_ELEMS (4096 / 32)
+/* initial table size, per spec */
+#define GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE 4096
+/* maximum table size we'll actually use */
+#define GRPC_CHTTP2_HPACKC_MAX_TABLE_SIZE (1024 * 1024)
 
 typedef struct {
   gpr_uint32 filter_elems_sum;
+  gpr_uint32 max_table_size;
+  gpr_uint32 max_table_elems;
+  gpr_uint32 cap_table_elems;
+  /** if non-zero, advertise to the decoder that we'll start using a table
+      of this size */
+  gpr_uint8 advertise_table_size_change;
+  /** maximum number of bytes we'll use for the decode table (to guard against
+      peers ooming us by setting decode table size high) */
+  gpr_uint32 max_usable_size;
   /* one before the lowest usable table index */
   gpr_uint32 tail_remote_index;
-  gpr_uint16 table_size;
-  gpr_uint16 table_elems;
+  gpr_uint32 table_size;
+  gpr_uint32 table_elems;
 
   /* filter tables for elems: this tables provides an approximate
      popularity count for particular hashes, and are used to determine whether
@@ -66,11 +78,15 @@ typedef struct {
   gpr_uint32 indices_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES];
   gpr_uint32 indices_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
 
-  gpr_uint16 table_elem_size[GRPC_CHTTP2_HPACKC_MAX_TABLE_ELEMS];
+  gpr_uint16 *table_elem_size;
 } grpc_chttp2_hpack_compressor;
 
 void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c);
 void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c);
+void grpc_chttp2_hpack_compressor_set_max_table_size(
+    grpc_chttp2_hpack_compressor *c, gpr_uint32 max_table_size);
+void grpc_chttp2_hpack_compressor_set_max_usable_size(
+    grpc_chttp2_hpack_compressor *c, gpr_uint32 max_table_size);
 
 void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c, gpr_uint32 id,
                                grpc_metadata_batch *metadata, int is_eof,
diff --git a/src/core/transport/chttp2/hpack_parser.c b/src/core/transport/chttp2/hpack_parser.c
index 03a7d63b09..d38ff68754 100644
--- a/src/core/transport/chttp2/hpack_parser.c
+++ b/src/core/transport/chttp2/hpack_parser.c
@@ -74,6 +74,8 @@ static int parse_begin(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
                        const gpr_uint8 *end);
 static int parse_error(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
                        const gpr_uint8 *end);
+static int parse_illegal_op(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
+                            const gpr_uint8 *end);
 
 static int parse_string_prefix(grpc_chttp2_hpack_parser *p,
                                const gpr_uint8 *cur, const gpr_uint8 *end);
@@ -156,7 +158,7 @@ static const grpc_chttp2_hpack_parser_state first_byte_action[] = {
     parse_lithdr_incidx_x, parse_lithdr_incidx_v, parse_lithdr_notidx,
     parse_lithdr_notidx_x, parse_lithdr_notidx_v, parse_lithdr_nvridx,
     parse_lithdr_nvridx_x, parse_lithdr_nvridx_v, parse_max_tbl_size,
-    parse_max_tbl_size_x,  parse_error};
+    parse_max_tbl_size_x,  parse_illegal_op};
 
 /* indexes the first byte to a parse state function - generated by
    gen_hpack_tables.c */
@@ -169,7 +171,7 @@ static const gpr_uint8 first_byte_lut[256] = {
     LITHDR_NVRIDX,   LITHDR_NVRIDX, LITHDR_NVRIDX, LITHDR_NVRIDX,
     LITHDR_NVRIDX,   LITHDR_NVRIDX, LITHDR_NVRIDX, LITHDR_NVRIDX,
     LITHDR_NVRIDX,   LITHDR_NVRIDX, LITHDR_NVRIDX, LITHDR_NVRIDX_X,
-    ILLEGAL,         MAX_TBL_SIZE,  MAX_TBL_SIZE,  MAX_TBL_SIZE,
+    MAX_TBL_SIZE,    MAX_TBL_SIZE,  MAX_TBL_SIZE,  MAX_TBL_SIZE,
     MAX_TBL_SIZE,    MAX_TBL_SIZE,  MAX_TBL_SIZE,  MAX_TBL_SIZE,
     MAX_TBL_SIZE,    MAX_TBL_SIZE,  MAX_TBL_SIZE,  MAX_TBL_SIZE,
     MAX_TBL_SIZE,    MAX_TBL_SIZE,  MAX_TBL_SIZE,  MAX_TBL_SIZE,
@@ -622,13 +624,15 @@ static const gpr_uint8 inverse_base64[256] = {
 };
 
 /* emission helpers */
-static void on_hdr(grpc_chttp2_hpack_parser *p, grpc_mdelem *md,
-                   int add_to_table) {
+static int on_hdr(grpc_chttp2_hpack_parser *p, grpc_mdelem *md,
+                  int add_to_table) {
   if (add_to_table) {
-    GRPC_MDELEM_REF(md);
-    grpc_chttp2_hptbl_add(&p->table, md);
+    if (!grpc_chttp2_hptbl_add(&p->table, md)) {
+      return 0;
+    }
   }
   p->on_header(p->on_header_user_data, md);
+  return 1;
 }
 
 static grpc_mdstr *take_string(grpc_chttp2_hpack_parser *p,
@@ -713,9 +717,12 @@ static int parse_stream_dep0(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
 static int finish_indexed_field(grpc_chttp2_hpack_parser *p,
                                 const gpr_uint8 *cur, const gpr_uint8 *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
+  if (md == NULL) {
+    gpr_log(GPR_ERROR, "Invalid HPACK index received: %d", p->index);
+    return 0;
+  }
   GRPC_MDELEM_REF(md);
-  on_hdr(p, md, 0);
-  return parse_begin(p, cur, end);
+  return on_hdr(p, md, 0) && parse_begin(p, cur, end);
 }
 
 /* parse an indexed field with index < 127 */
@@ -741,19 +748,19 @@ static int parse_indexed_field_x(grpc_chttp2_hpack_parser *p,
 static int finish_lithdr_incidx(grpc_chttp2_hpack_parser *p,
                                 const gpr_uint8 *cur, const gpr_uint8 *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  on_hdr(p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
-                                              take_string(p, &p->value)),
-         1);
-  return parse_begin(p, cur, end);
+  return on_hdr(p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
+                                                     take_string(p, &p->value)),
+                1) &&
+         parse_begin(p, cur, end);
 }
 
 /* finish a literal header with incremental indexing with no index */
 static int finish_lithdr_incidx_v(grpc_chttp2_hpack_parser *p,
                                   const gpr_uint8 *cur, const gpr_uint8 *end) {
-  on_hdr(p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
-                                              take_string(p, &p->value)),
-         1);
-  return parse_begin(p, cur, end);
+  return on_hdr(p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
+                                                     take_string(p, &p->value)),
+                1) &&
+         parse_begin(p, cur, end);
 }
 
 /* parse a literal header with incremental indexing; index < 63 */
@@ -792,19 +799,19 @@ static int parse_lithdr_incidx_v(grpc_chttp2_hpack_parser *p,
 static int finish_lithdr_notidx(grpc_chttp2_hpack_parser *p,
                                 const gpr_uint8 *cur, const gpr_uint8 *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  on_hdr(p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
-                                              take_string(p, &p->value)),
-         0);
-  return parse_begin(p, cur, end);
+  return on_hdr(p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
+                                                     take_string(p, &p->value)),
+                0) &&
+         parse_begin(p, cur, end);
 }
 
 /* finish a literal header without incremental indexing with index = 0 */
 static int finish_lithdr_notidx_v(grpc_chttp2_hpack_parser *p,
                                   const gpr_uint8 *cur, const gpr_uint8 *end) {
-  on_hdr(p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
-                                              take_string(p, &p->value)),
-         0);
-  return parse_begin(p, cur, end);
+  return on_hdr(p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
+                                                     take_string(p, &p->value)),
+                0) &&
+         parse_begin(p, cur, end);
 }
 
 /* parse a literal header without incremental indexing; index < 15 */
@@ -843,19 +850,19 @@ static int parse_lithdr_notidx_v(grpc_chttp2_hpack_parser *p,
 static int finish_lithdr_nvridx(grpc_chttp2_hpack_parser *p,
                                 const gpr_uint8 *cur, const gpr_uint8 *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  on_hdr(p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
-                                              take_string(p, &p->value)),
-         0);
-  return parse_begin(p, cur, end);
+  return on_hdr(p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
+                                                     take_string(p, &p->value)),
+                0) &&
+         parse_begin(p, cur, end);
 }
 
 /* finish a literal header that is never indexed with an extra value */
 static int finish_lithdr_nvridx_v(grpc_chttp2_hpack_parser *p,
                                   const gpr_uint8 *cur, const gpr_uint8 *end) {
-  on_hdr(p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
-                                              take_string(p, &p->value)),
-         0);
-  return parse_begin(p, cur, end);
+  return on_hdr(p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
+                                                     take_string(p, &p->value)),
+                0) &&
+         parse_begin(p, cur, end);
 }
 
 /* parse a literal header that is never indexed; index < 15 */
@@ -894,14 +901,14 @@ static int parse_lithdr_nvridx_v(grpc_chttp2_hpack_parser *p,
 static int finish_max_tbl_size(grpc_chttp2_hpack_parser *p,
                                const gpr_uint8 *cur, const gpr_uint8 *end) {
   gpr_log(GPR_INFO, "MAX TABLE SIZE: %d", p->index);
-  abort(); /* not implemented */
-  return parse_begin(p, cur, end);
+  return grpc_chttp2_hptbl_set_current_table_size(&p->table, p->index) &&
+         parse_begin(p, cur, end);
 }
 
 /* parse a max table size change, max size < 15 */
 static int parse_max_tbl_size(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
                               const gpr_uint8 *end) {
-  p->index = (*cur) & 0xf;
+  p->index = (*cur) & 0x1f;
   return finish_max_tbl_size(p, cur + 1, end);
 }
 
@@ -911,7 +918,7 @@ static int parse_max_tbl_size_x(grpc_chttp2_hpack_parser *p,
   static const grpc_chttp2_hpack_parser_state and_then[] = {
       finish_max_tbl_size};
   p->next_state = and_then;
-  p->index = 0xf;
+  p->index = 0x1f;
   p->parsing.value = &p->index;
   return parse_value0(p, cur + 1, end);
 }
@@ -923,6 +930,13 @@ static int parse_error(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
   return 0;
 }
 
+static int parse_illegal_op(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
+                            const gpr_uint8 *end) {
+  GPR_ASSERT(cur != end);
+  gpr_log(GPR_DEBUG, "Illegal hpack op code %d", *cur);
+  return parse_error(p, cur, end);
+}
+
 /* parse the 1st byte of a varint into p->parsing.value
    no overflow is possible */
 static int parse_value0(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
diff --git a/src/core/transport/chttp2/hpack_table.c b/src/core/transport/chttp2/hpack_table.c
index f66745f069..59060daad3 100644
--- a/src/core/transport/chttp2/hpack_table.c
+++ b/src/core/transport/chttp2/hpack_table.c
@@ -36,7 +36,9 @@
 #include <assert.h>
 #include <string.h>
 
+#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+
 #include "src/core/support/murmur_hash.h"
 
 static struct {
@@ -169,11 +171,21 @@ static struct {
     {"www-authenticate", ""},
 };
 
+static gpr_uint32 entries_for_bytes(gpr_uint32 bytes) {
+  return (bytes + GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD - 1) /
+         GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
+}
+
 void grpc_chttp2_hptbl_init(grpc_chttp2_hptbl *tbl) {
   size_t i;
 
   memset(tbl, 0, sizeof(*tbl));
-  tbl->max_bytes = GRPC_CHTTP2_INITIAL_HPACK_TABLE_SIZE;
+  tbl->current_table_bytes = tbl->max_bytes =
+      GRPC_CHTTP2_INITIAL_HPACK_TABLE_SIZE;
+  tbl->max_entries = tbl->cap_entries =
+      entries_for_bytes(tbl->current_table_bytes);
+  tbl->ents = gpr_malloc(sizeof(*tbl->ents) * tbl->cap_entries);
+  memset(tbl->ents, 0, sizeof(*tbl->ents) * tbl->cap_entries);
   for (i = 1; i <= GRPC_CHTTP2_LAST_STATIC_ENTRY; i++) {
     tbl->static_ents[i - 1] =
         grpc_mdelem_from_strings(static_table[i].key, static_table[i].value);
@@ -186,9 +198,9 @@ void grpc_chttp2_hptbl_destroy(grpc_chttp2_hptbl *tbl) {
     GRPC_MDELEM_UNREF(tbl->static_ents[i]);
   }
   for (i = 0; i < tbl->num_ents; i++) {
-    GRPC_MDELEM_UNREF(
-        tbl->ents[(tbl->first_ent + i) % GRPC_CHTTP2_MAX_TABLE_COUNT]);
+    GRPC_MDELEM_UNREF(tbl->ents[(tbl->first_ent + i) % tbl->cap_entries]);
   }
+  gpr_free(tbl->ents);
 }
 
 grpc_mdelem *grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
@@ -200,8 +212,8 @@ grpc_mdelem *grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
   /* Otherwise, find the value in the list of valid entries */
   tbl_index -= (GRPC_CHTTP2_LAST_STATIC_ENTRY + 1);
   if (tbl_index < tbl->num_ents) {
-    gpr_uint32 offset = (tbl->num_ents - 1u - tbl_index + tbl->first_ent) %
-                        GRPC_CHTTP2_MAX_TABLE_COUNT;
+    gpr_uint32 offset =
+        (tbl->num_ents - 1u - tbl_index + tbl->first_ent) % tbl->cap_entries;
     return tbl->ents[offset];
   }
   /* Invalid entry: return error */
@@ -215,21 +227,81 @@ static void evict1(grpc_chttp2_hptbl *tbl) {
                       GPR_SLICE_LENGTH(first_ent->value->slice) +
                       GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
   GPR_ASSERT(elem_bytes <= tbl->mem_used);
-  tbl->mem_used = (gpr_uint16)(tbl->mem_used - elem_bytes);
-  tbl->first_ent =
-      (gpr_uint16)((tbl->first_ent + 1) % GRPC_CHTTP2_MAX_TABLE_COUNT);
+  tbl->mem_used -= (gpr_uint32)elem_bytes;
+  tbl->first_ent = ((tbl->first_ent + 1) % tbl->cap_entries);
   tbl->num_ents--;
   GRPC_MDELEM_UNREF(first_ent);
 }
 
-void grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
+static void rebuild_ents(grpc_chttp2_hptbl *tbl, gpr_uint32 new_cap) {
+  grpc_mdelem **ents = gpr_malloc(sizeof(*ents) * new_cap);
+  gpr_uint32 i;
+
+  for (i = 0; i < tbl->num_ents; i++) {
+    ents[i] = tbl->ents[(tbl->first_ent + i) % tbl->cap_entries];
+  }
+  gpr_free(tbl->ents);
+  tbl->ents = ents;
+  tbl->cap_entries = new_cap;
+  tbl->first_ent = 0;
+}
+
+void grpc_chttp2_hptbl_set_max_bytes(grpc_chttp2_hptbl *tbl,
+                                     gpr_uint32 max_bytes) {
+  if (tbl->max_bytes == max_bytes) {
+    return;
+  }
+  gpr_log(GPR_DEBUG, "Update hpack parser max size to %d", max_bytes);
+  while (tbl->mem_used > max_bytes) {
+    evict1(tbl);
+  }
+  tbl->max_bytes = max_bytes;
+}
+
+int grpc_chttp2_hptbl_set_current_table_size(grpc_chttp2_hptbl *tbl,
+                                             gpr_uint32 bytes) {
+  if (tbl->current_table_bytes == bytes) {
+    return 1;
+  }
+  if (bytes > tbl->max_bytes) {
+    gpr_log(GPR_ERROR,
+            "Attempt to make hpack table %d bytes when max is %d bytes", bytes,
+            tbl->max_bytes);
+    return 0;
+  }
+  gpr_log(GPR_DEBUG, "Update hpack parser table size to %d", bytes);
+  while (tbl->mem_used > bytes) {
+    evict1(tbl);
+  }
+  tbl->current_table_bytes = bytes;
+  tbl->max_entries = entries_for_bytes(bytes);
+  if (tbl->max_entries > tbl->cap_entries) {
+    rebuild_ents(tbl, GPR_MAX(tbl->max_entries, 2 * tbl->cap_entries));
+  } else if (tbl->max_entries < tbl->cap_entries / 3) {
+    gpr_uint32 new_cap = GPR_MAX(tbl->max_entries, 16u);
+    if (new_cap != tbl->cap_entries) {
+      rebuild_ents(tbl, new_cap);
+    }
+  }
+  return 1;
+}
+
+int grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
   /* determine how many bytes of buffer this entry represents */
   size_t elem_bytes = GPR_SLICE_LENGTH(md->key->slice) +
                       GPR_SLICE_LENGTH(md->value->slice) +
                       GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
 
+  if (tbl->current_table_bytes > tbl->max_bytes) {
+    gpr_log(GPR_ERROR,
+            "HPACK max table size reduced to %d but not reflected by hpack "
+            "stream (still at %d)",
+            tbl->max_bytes, tbl->current_table_bytes);
+    return 0;
+  }
+
   /* we can't add elements bigger than the max table size */
-  if (elem_bytes > tbl->max_bytes) {
+  if (elem_bytes > tbl->current_table_bytes) {
     /* HPACK draft 10 section 4.4 states:
      * If the size of the new entry is less than or equal to the maximum
      * size, that entry is added to the table.  It is not an error to
@@ -242,44 +314,43 @@ void grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
     while (tbl->num_ents) {
       evict1(tbl);
     }
-    return;
+    return 1;
   }
 
   /* evict entries to ensure no overflow */
-  while (elem_bytes > (size_t)tbl->max_bytes - tbl->mem_used) {
+  while (elem_bytes > (size_t)tbl->current_table_bytes - tbl->mem_used) {
     evict1(tbl);
   }
 
   /* copy the finalized entry in */
-  tbl->ents[tbl->last_ent] = md;
+  tbl->ents[(tbl->first_ent + tbl->num_ents) % tbl->cap_entries] =
+      GRPC_MDELEM_REF(md);
 
   /* update accounting values */
-  tbl->last_ent =
-      (gpr_uint16)((tbl->last_ent + 1) % GRPC_CHTTP2_MAX_TABLE_COUNT);
   tbl->num_ents++;
-  tbl->mem_used = (gpr_uint16)(tbl->mem_used + elem_bytes);
+  tbl->mem_used += (gpr_uint32)elem_bytes;
+  return 1;
 }
 
 grpc_chttp2_hptbl_find_result grpc_chttp2_hptbl_find(
     const grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
   grpc_chttp2_hptbl_find_result r = {0, 0};
-  gpr_uint16 i;
+  gpr_uint32 i;
 
   /* See if the string is in the static table */
   for (i = 0; i < GRPC_CHTTP2_LAST_STATIC_ENTRY; i++) {
     grpc_mdelem *ent = tbl->static_ents[i];
     if (md->key != ent->key) continue;
-    r.index = (gpr_uint16)(i + 1);
+    r.index = i + 1u;
     r.has_value = md->value == ent->value;
     if (r.has_value) return r;
   }
 
   /* Scan the dynamic table */
   for (i = 0; i < tbl->num_ents; i++) {
-    gpr_uint16 idx =
-        (gpr_uint16)(tbl->num_ents - i + GRPC_CHTTP2_LAST_STATIC_ENTRY);
-    grpc_mdelem *ent =
-        tbl->ents[(tbl->first_ent + i) % GRPC_CHTTP2_MAX_TABLE_COUNT];
+    gpr_uint32 idx =
+        (gpr_uint32)(tbl->num_ents - i + GRPC_CHTTP2_LAST_STATIC_ENTRY);
+    grpc_mdelem *ent = tbl->ents[(tbl->first_ent + i) % tbl->cap_entries];
     if (md->key != ent->key) continue;
     r.index = idx;
     r.has_value = md->value == ent->value;
diff --git a/src/core/transport/chttp2/hpack_table.h b/src/core/transport/chttp2/hpack_table.h
index d2587e0758..a173eec30c 100644
--- a/src/core/transport/chttp2/hpack_table.h
+++ b/src/core/transport/chttp2/hpack_table.h
@@ -49,46 +49,58 @@
 #define GRPC_CHTTP2_MAX_HPACK_TABLE_SIZE GRPC_CHTTP2_INITIAL_HPACK_TABLE_SIZE
 /* Per entry overhead bytes as per the spec */
 #define GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD 32
+#if 0
 /* Maximum number of entries we could possibly fit in the table, given defined
    overheads */
 #define GRPC_CHTTP2_MAX_TABLE_COUNT                                            \
   ((GRPC_CHTTP2_MAX_HPACK_TABLE_SIZE + GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD - 1) / \
    GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD)
+#endif
 
 /* hpack decoder table */
 typedef struct {
   /* the first used entry in ents */
-  gpr_uint16 first_ent;
-  /* the last used entry in ents */
-  gpr_uint16 last_ent;
+  gpr_uint32 first_ent;
   /* how many entries are in the table */
-  gpr_uint16 num_ents;
+  gpr_uint32 num_ents;
   /* the amount of memory used by the table, according to the hpack algorithm */
-  gpr_uint16 mem_used;
+  gpr_uint32 mem_used;
   /* the max memory allowed to be used by the table, according to the hpack
      algorithm */
-  gpr_uint16 max_bytes;
+  gpr_uint32 max_bytes;
+  /* the currently agreed size of the table, according to the hpack algorithm */
+  gpr_uint32 current_table_bytes;
+  /* Maximum number of entries we could possibly fit in the table, given defined
+     overheads */
+  gpr_uint32 max_entries;
+  /* Number of entries allocated in ents */
+  gpr_uint32 cap_entries;
   /* a circular buffer of headers - this is stored in the opposite order to
      what hpack specifies, in order to simplify table management a little...
      meaning lookups need to SUBTRACT from the end position */
-  grpc_mdelem *ents[GRPC_CHTTP2_MAX_TABLE_COUNT];
+  grpc_mdelem **ents;
   grpc_mdelem *static_ents[GRPC_CHTTP2_LAST_STATIC_ENTRY];
 } grpc_chttp2_hptbl;
 
 /* initialize a hpack table */
 void grpc_chttp2_hptbl_init(grpc_chttp2_hptbl *tbl);
 void grpc_chttp2_hptbl_destroy(grpc_chttp2_hptbl *tbl);
+void grpc_chttp2_hptbl_set_max_bytes(grpc_chttp2_hptbl *tbl,
+                                     gpr_uint32 max_bytes);
+int grpc_chttp2_hptbl_set_current_table_size(grpc_chttp2_hptbl *tbl,
+                                             gpr_uint32 bytes);
 
 /* lookup a table entry based on its hpack index */
 grpc_mdelem *grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
                                       gpr_uint32 index);
 /* add a table entry to the index */
-void grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl, grpc_mdelem *md);
+int grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl,
+                          grpc_mdelem *md) GRPC_MUST_USE_RESULT;
 /* Find a key/value pair in the table... returns the index in the table of the
    most similar entry, or 0 if the value was not found */
 typedef struct {
-  gpr_uint16 index;
-  gpr_uint8 has_value;
+  gpr_uint32 index;
+  int has_value;
 } grpc_chttp2_hptbl_find_result;
 grpc_chttp2_hptbl_find_result grpc_chttp2_hptbl_find(
     const grpc_chttp2_hptbl *tbl, grpc_mdelem *md);
diff --git a/src/core/transport/chttp2/internal.h b/src/core/transport/chttp2/internal.h
index 99b5187d46..ebfa347398 100644
--- a/src/core/transport/chttp2/internal.h
+++ b/src/core/transport/chttp2/internal.h
@@ -227,6 +227,9 @@ struct grpc_chttp2_transport_parsing {
   /** was a goaway frame received? */
   gpr_uint8 goaway_received;
 
+  /** the last sent max_table_size setting */
+  gpr_uint32 last_sent_max_table_size;
+
   /** initial window change */
   gpr_int64 initial_window_update;
 
@@ -479,7 +482,8 @@ struct grpc_chttp2_stream {
 /** Someone is unlocking the transport mutex: check to see if writes
     are required, and schedule them if so */
 int grpc_chttp2_unlocking_check_writes(grpc_chttp2_transport_global *global,
-                                       grpc_chttp2_transport_writing *writing);
+                                       grpc_chttp2_transport_writing *writing,
+                                       int is_parsing);
 void grpc_chttp2_perform_writes(
     grpc_exec_ctx *exec_ctx, grpc_chttp2_transport_writing *transport_writing,
     grpc_endpoint *endpoint);
diff --git a/src/core/transport/chttp2/parsing.c b/src/core/transport/chttp2/parsing.c
index 2872a3a5c1..467e734cc3 100644
--- a/src/core/transport/chttp2/parsing.c
+++ b/src/core/transport/chttp2/parsing.c
@@ -79,6 +79,9 @@ void grpc_chttp2_prepare_to_read(
   GPR_TIMER_BEGIN("grpc_chttp2_prepare_to_read", 0);
 
   transport_parsing->next_stream_id = transport_global->next_stream_id;
+  transport_parsing->last_sent_max_table_size =
+      transport_global->settings[GRPC_SENT_SETTINGS]
+                                [GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE];
 
   /* update the parsing view of incoming window */
   while (grpc_chttp2_list_pop_unannounced_incoming_window_available(
@@ -128,6 +131,7 @@ void grpc_chttp2_publish_reads(
            transport_global->settings[GRPC_SENT_SETTINGS],
            GRPC_CHTTP2_NUM_SETTINGS * sizeof(gpr_uint32));
     transport_parsing->settings_ack_received = 0;
+    transport_global->sent_local_settings = 0;
   }
 
   /* move goaway to the global state if we received one (it will be
@@ -818,6 +822,9 @@ static int init_settings_frame_parser(
   }
   if (transport_parsing->incoming_frame_flags & GRPC_CHTTP2_FLAG_ACK) {
     transport_parsing->settings_ack_received = 1;
+    grpc_chttp2_hptbl_set_max_bytes(
+        &transport_parsing->hpack_parser.table,
+        transport_parsing->last_sent_max_table_size);
   }
   transport_parsing->parser = grpc_chttp2_settings_parser_parse;
   transport_parsing->parser_data = &transport_parsing->simple.settings;
diff --git a/src/core/transport/chttp2/writing.c b/src/core/transport/chttp2/writing.c
index 353e476e40..3cb28f8f0c 100644
--- a/src/core/transport/chttp2/writing.c
+++ b/src/core/transport/chttp2/writing.c
@@ -45,7 +45,7 @@ static void finalize_outbuf(grpc_exec_ctx *exec_ctx,
 
 int grpc_chttp2_unlocking_check_writes(
     grpc_chttp2_transport_global *transport_global,
-    grpc_chttp2_transport_writing *transport_writing) {
+    grpc_chttp2_transport_writing *transport_writing, int is_parsing) {
   grpc_chttp2_stream_global *stream_global;
   grpc_chttp2_stream_writing *stream_writing;
 
@@ -55,8 +55,13 @@ int grpc_chttp2_unlocking_check_writes(
   gpr_slice_buffer_swap(&transport_global->qbuf, &transport_writing->outbuf);
   GPR_ASSERT(transport_global->qbuf.count == 0);
 
+  grpc_chttp2_hpack_compressor_set_max_table_size(
+      &transport_writing->hpack_compressor,
+      transport_global->settings[GRPC_PEER_SETTINGS]
+                                [GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE]);
+
   if (transport_global->dirtied_local_settings &&
-      !transport_global->sent_local_settings) {
+      !transport_global->sent_local_settings && !is_parsing) {
     gpr_slice_buffer_add(
         &transport_writing->outbuf,
         grpc_chttp2_settings_create(