Merge pull request #10473 from ctiller/truebin

True Binary Encoding

10 files changed, 308 insertions, 142 deletions

diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 097b3794e5..29ed4bf90e 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -365,6 +365,8 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                DEFAULT_WINDOW);
   push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
                DEFAULT_MAX_HEADER_LIST_SIZE);
+  push_setting(exec_ctx, t,
+               GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA, 1);
 
   t->ping_policy = (grpc_chttp2_repeated_ping_policy){
       .max_pings_without_data = DEFAULT_MAX_PINGS_BETWEEN_DATA,
@@ -495,26 +497,31 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
           grpc_chttp2_setting_id setting_id;
           grpc_integer_options integer_options;
           bool availability[2] /* server, client */;
-        } settings_map[] = {{GRPC_ARG_MAX_CONCURRENT_STREAMS,
-                             GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
-                             {-1, 0, INT32_MAX},
-                             {true, false}},
-                            {GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER,
-                             GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
-                             {-1, 0, INT32_MAX},
-                             {true, true}},
-                            {GRPC_ARG_MAX_METADATA_SIZE,
-                             GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
-                             {-1, 0, INT32_MAX},
-                             {true, true}},
-                            {GRPC_ARG_HTTP2_MAX_FRAME_SIZE,
-                             GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
-                             {-1, 16384, 16777215},
-                             {true, true}},
-                            {GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES,
-                             GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
-                             {-1, 5, INT32_MAX},
-                             {true, true}}};
+        } settings_map[] = {
+            {GRPC_ARG_MAX_CONCURRENT_STREAMS,
+             GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
+             {-1, 0, INT32_MAX},
+             {true, false}},
+            {GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER,
+             GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
+             {-1, 0, INT32_MAX},
+             {true, true}},
+            {GRPC_ARG_MAX_METADATA_SIZE,
+             GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
+             {-1, 0, INT32_MAX},
+             {true, true}},
+            {GRPC_ARG_HTTP2_MAX_FRAME_SIZE,
+             GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
+             {-1, 16384, 16777215},
+             {true, true}},
+            {GRPC_ARG_HTTP2_ENABLE_TRUE_BINARY,
+             GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA,
+             {1, 0, 1},
+             {true, true}},
+            {GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES,
+             GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
+             {-1, 5, INT32_MAX},
+             {true, true}}};
         for (j = 0; j < (int)GPR_ARRAY_SIZE(settings_map); j++) {
           if (0 == strcmp(channel_args->args[i].key,
                           settings_map[j].channel_arg_name)) {
diff --git a/src/core/ext/transport/chttp2/transport/frame_settings.c b/src/core/ext/transport/chttp2/transport/frame_settings.c
index 16881c0707..4f2b827832 100644
--- a/src/core/ext/transport/chttp2/transport/frame_settings.c
+++ b/src/core/ext/transport/chttp2/transport/frame_settings.c
@@ -46,29 +46,6 @@
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/transport/http2_errors.h"
 
-#define MAX_MAX_HEADER_LIST_SIZE (1024 * 1024 * 1024)
-
-/* HTTP/2 mandated initial connection settings */
-const grpc_chttp2_setting_parameters
-    grpc_chttp2_settings_parameters[GRPC_CHTTP2_NUM_SETTINGS] = {
-        {NULL, 0, 0, 0, GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE,
-         GRPC_HTTP2_PROTOCOL_ERROR},
-        {"HEADER_TABLE_SIZE", 4096, 0, 0xffffffff,
-         GRPC_CHTTP2_CLAMP_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
-        {"ENABLE_PUSH", 1, 0, 1, GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE,
-         GRPC_HTTP2_PROTOCOL_ERROR},
-        {"MAX_CONCURRENT_STREAMS", 0xffffffffu, 0, 0xffffffffu,
-         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
-        {"INITIAL_WINDOW_SIZE", 65535, 0, 0x7fffffffu,
-         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE,
-         GRPC_HTTP2_FLOW_CONTROL_ERROR},
-        {"MAX_FRAME_SIZE", 16384, 16384, 16777215,
-         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
-        {"MAX_HEADER_LIST_SIZE", MAX_MAX_HEADER_LIST_SIZE, 0,
-         MAX_MAX_HEADER_LIST_SIZE, GRPC_CHTTP2_CLAMP_INVALID_VALUE,
-         GRPC_HTTP2_PROTOCOL_ERROR},
-};
-
 static uint8_t *fill_header(uint8_t *out, uint32_t length, uint8_t flags) {
   *out++ = (uint8_t)(length >> 16);
   *out++ = (uint8_t)(length >> 8);
@@ -98,9 +75,8 @@ grpc_slice grpc_chttp2_settings_create(uint32_t *old, const uint32_t *new,
 
   for (i = 0; i < count; i++) {
     if (new[i] != old[i] || (force_mask & (1u << i)) != 0) {
-      GPR_ASSERT(i);
-      *p++ = (uint8_t)(i >> 8);
-      *p++ = (uint8_t)(i);
+      *p++ = (uint8_t)(grpc_setting_id_to_wire_id[i] >> 8);
+      *p++ = (uint8_t)(grpc_setting_id_to_wire_id[i]);
       *p++ = (uint8_t)(new[i] >> 24);
       *p++ = (uint8_t)(new[i] >> 16);
       *p++ = (uint8_t)(new[i] >> 8);
@@ -154,6 +130,7 @@ grpc_error *grpc_chttp2_settings_parser_parse(grpc_exec_ctx *exec_ctx, void *p,
   const uint8_t *cur = GRPC_SLICE_START_PTR(slice);
   const uint8_t *end = GRPC_SLICE_END_PTR(slice);
   char *msg;
+  grpc_chttp2_setting_id id;
 
   if (parser->is_ack) {
     return GRPC_ERROR_NONE;
@@ -216,9 +193,9 @@ grpc_error *grpc_chttp2_settings_parser_parse(grpc_exec_ctx *exec_ctx, void *p,
         parser->value |= *cur;
         cur++;
 
-        if (parser->id > 0 && parser->id < GRPC_CHTTP2_NUM_SETTINGS) {
+        if (grpc_wire_id_to_setting_id(parser->id, &id)) {
           const grpc_chttp2_setting_parameters *sp =
-              &grpc_chttp2_settings_parameters[parser->id];
+              &grpc_chttp2_settings_parameters[id];
           if (parser->value < sp->min_value || parser->value > sp->max_value) {
             switch (sp->invalid_value_behavior) {
               case GRPC_CHTTP2_CLAMP_INVALID_VALUE:
@@ -237,19 +214,19 @@ grpc_error *grpc_chttp2_settings_parser_parse(grpc_exec_ctx *exec_ctx, void *p,
                 return err;
             }
           }
-          if (parser->id == GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE &&
-              parser->incoming_settings[parser->id] != parser->value) {
+          if (id == GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE &&
+              parser->incoming_settings[id] != parser->value) {
             t->initial_window_update +=
-                (int64_t)parser->value - parser->incoming_settings[parser->id];
+                (int64_t)parser->value - parser->incoming_settings[id];
             if (grpc_http_trace) {
               gpr_log(GPR_DEBUG, "adding %d for initial_window change",
                       (int)t->initial_window_update);
             }
           }
-          parser->incoming_settings[parser->id] = parser->value;
+          parser->incoming_settings[id] = parser->value;
           if (grpc_http_trace) {
-            gpr_log(GPR_DEBUG, "CHTTP2:%s:%s: got setting %d = %d",
-                    t->is_client ? "CLI" : "SVR", t->peer_string, parser->id,
+            gpr_log(GPR_DEBUG, "CHTTP2:%s:%s: got setting %s = %d",
+                    t->is_client ? "CLI" : "SVR", t->peer_string, sp->name,
                     parser->value);
           }
         } else if (grpc_http_trace) {
diff --git a/src/core/ext/transport/chttp2/transport/frame_settings.h b/src/core/ext/transport/chttp2/transport/frame_settings.h
index 44137798c0..2a85d0dba7 100644
--- a/src/core/ext/transport/chttp2/transport/frame_settings.h
+++ b/src/core/ext/transport/chttp2/transport/frame_settings.h
@@ -37,6 +37,7 @@
 #include <grpc/slice.h>
 #include <grpc/support/port_platform.h>
 #include "src/core/ext/transport/chttp2/transport/frame.h"
+#include "src/core/ext/transport/chttp2/transport/http2_settings.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 
 typedef enum {
@@ -48,17 +49,6 @@ typedef enum {
   GRPC_CHTTP2_SPS_VAL3
 } grpc_chttp2_settings_parse_state;
 
-/* The things HTTP/2 defines as connection level settings */
-typedef enum {
-  GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE = 1,
-  GRPC_CHTTP2_SETTINGS_ENABLE_PUSH = 2,
-  GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS = 3,
-  GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE = 4,
-  GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE = 5,
-  GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE = 6,
-  GRPC_CHTTP2_NUM_SETTINGS
-} grpc_chttp2_setting_id;
-
 typedef struct {
   grpc_chttp2_settings_parse_state state;
   uint32_t *target_settings;
@@ -68,24 +58,6 @@ typedef struct {
   uint32_t incoming_settings[GRPC_CHTTP2_NUM_SETTINGS];
 } grpc_chttp2_settings_parser;
 
-typedef enum {
-  GRPC_CHTTP2_CLAMP_INVALID_VALUE,
-  GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE
-} grpc_chttp2_invalid_value_behavior;
-
-typedef struct {
-  const char *name;
-  uint32_t default_value;
-  uint32_t min_value;
-  uint32_t max_value;
-  grpc_chttp2_invalid_value_behavior invalid_value_behavior;
-  uint32_t error_value;
-} grpc_chttp2_setting_parameters;
-
-/* HTTP/2 mandated connection setting parameters */
-extern const grpc_chttp2_setting_parameters
-    grpc_chttp2_settings_parameters[GRPC_CHTTP2_NUM_SETTINGS];
-
 /* Create a settings frame by diffing old & new, and updating old to be new */
 grpc_slice grpc_chttp2_settings_create(uint32_t *old, const uint32_t *newval,
                                        uint32_t force_mask, size_t count);
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.c b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
index 84586cd998..b1bc677a7a 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
@@ -86,6 +86,7 @@ typedef struct {
   grpc_transport_one_way_stats *stats;
   /* maximum size of a frame */
   size_t max_frame_size;
+  bool use_true_binary_metadata;
 } framer_state;
 
 /* fills p (which is expected to be 9 bytes long) with a data frame header */
@@ -290,86 +291,113 @@ static void emit_indexed(grpc_chttp2_hpack_compressor *c, uint32_t elem_index,
                            len);
 }
 
-static grpc_slice get_wire_value(grpc_mdelem elem, uint8_t *huffman_prefix) {
+typedef struct {
+  grpc_slice data;
+  uint8_t huffman_prefix;
+  bool insert_null_before_wire_value;
+} wire_value;
+
+static wire_value get_wire_value(grpc_mdelem elem, bool true_binary_enabled) {
   if (grpc_is_binary_header(GRPC_MDKEY(elem))) {
-    *huffman_prefix = 0x80;
-    return grpc_chttp2_base64_encode_and_huffman_compress(GRPC_MDVALUE(elem));
+    if (true_binary_enabled) {
+      return (wire_value){
+          .huffman_prefix = 0x00,
+          .insert_null_before_wire_value = true,
+          .data = grpc_slice_ref_internal(GRPC_MDVALUE(elem)),
+      };
+    } else {
+      return (wire_value){
+          .huffman_prefix = 0x80,
+          .insert_null_before_wire_value = false,
+          .data = grpc_chttp2_base64_encode_and_huffman_compress(
+              GRPC_MDVALUE(elem)),
+      };
+    }
+  } else {
+    /* TODO(ctiller): opportunistically compress non-binary headers */
+    return (wire_value){
+        .huffman_prefix = 0x00,
+        .insert_null_before_wire_value = false,
+        .data = grpc_slice_ref_internal(GRPC_MDVALUE(elem)),
+    };
   }
-  /* TODO(ctiller): opportunistically compress non-binary headers */
-  *huffman_prefix = 0x00;
-  return grpc_slice_ref_internal(GRPC_MDVALUE(elem));
+}
+
+static size_t wire_value_length(wire_value v) {
+  return GPR_SLICE_LENGTH(v.data) + v.insert_null_before_wire_value;
+}
+
+static void add_wire_value(framer_state *st, wire_value v) {
+  if (v.insert_null_before_wire_value) *add_tiny_header_data(st, 1) = 0;
+  add_header_data(st, v.data);
 }
 
 static void emit_lithdr_incidx(grpc_chttp2_hpack_compressor *c,
                                uint32_t key_index, grpc_mdelem elem,
                                framer_state *st) {
   uint32_t len_pfx = GRPC_CHTTP2_VARINT_LENGTH(key_index, 2);
-  uint8_t huffman_prefix;
-  grpc_slice value_slice = get_wire_value(elem, &huffman_prefix);
-  size_t len_val = GRPC_SLICE_LENGTH(value_slice);
+  wire_value value = get_wire_value(elem, st->use_true_binary_metadata);
+  size_t len_val = wire_value_length(value);
   uint32_t len_val_len;
   GPR_ASSERT(len_val <= UINT32_MAX);
   len_val_len = GRPC_CHTTP2_VARINT_LENGTH((uint32_t)len_val, 1);
   GRPC_CHTTP2_WRITE_VARINT(key_index, 2, 0x40,
                            add_tiny_header_data(st, len_pfx), len_pfx);
-  GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, huffman_prefix,
+  GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, value.huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, value_slice);
+  add_wire_value(st, value);
 }
 
 static void emit_lithdr_noidx(grpc_chttp2_hpack_compressor *c,
                               uint32_t key_index, grpc_mdelem elem,
                               framer_state *st) {
   uint32_t len_pfx = GRPC_CHTTP2_VARINT_LENGTH(key_index, 4);
-  uint8_t huffman_prefix;
-  grpc_slice value_slice = get_wire_value(elem, &huffman_prefix);
-  size_t len_val = GRPC_SLICE_LENGTH(value_slice);
+  wire_value value = get_wire_value(elem, st->use_true_binary_metadata);
+  size_t len_val = wire_value_length(value);
   uint32_t len_val_len;
   GPR_ASSERT(len_val <= UINT32_MAX);
   len_val_len = GRPC_CHTTP2_VARINT_LENGTH((uint32_t)len_val, 1);
   GRPC_CHTTP2_WRITE_VARINT(key_index, 4, 0x00,
                            add_tiny_header_data(st, len_pfx), len_pfx);
-  GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, huffman_prefix,
+  GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, value.huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, value_slice);
+  add_wire_value(st, value);
 }
 
 static void emit_lithdr_incidx_v(grpc_chttp2_hpack_compressor *c,
                                  grpc_mdelem elem, framer_state *st) {
   uint32_t len_key = (uint32_t)GRPC_SLICE_LENGTH(GRPC_MDKEY(elem));
-  uint8_t huffman_prefix;
-  grpc_slice value_slice = get_wire_value(elem, &huffman_prefix);
-  uint32_t len_val = (uint32_t)GRPC_SLICE_LENGTH(value_slice);
+  wire_value value = get_wire_value(elem, st->use_true_binary_metadata);
+  uint32_t len_val = (uint32_t)wire_value_length(value);
   uint32_t len_key_len = GRPC_CHTTP2_VARINT_LENGTH(len_key, 1);
   uint32_t len_val_len = GRPC_CHTTP2_VARINT_LENGTH(len_val, 1);
   GPR_ASSERT(len_key <= UINT32_MAX);
-  GPR_ASSERT(GRPC_SLICE_LENGTH(value_slice) <= UINT32_MAX);
+  GPR_ASSERT(wire_value_length(value) <= UINT32_MAX);
   *add_tiny_header_data(st, 1) = 0x40;
   GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00,
                            add_tiny_header_data(st, len_key_len), len_key_len);
   add_header_data(st, grpc_slice_ref_internal(GRPC_MDKEY(elem)));
-  GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix,
+  GRPC_CHTTP2_WRITE_VARINT(len_val, 1, value.huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, value_slice);
+  add_wire_value(st, value);
 }
 
 static void emit_lithdr_noidx_v(grpc_chttp2_hpack_compressor *c,
                                 grpc_mdelem elem, framer_state *st) {
   uint32_t len_key = (uint32_t)GRPC_SLICE_LENGTH(GRPC_MDKEY(elem));
-  uint8_t huffman_prefix;
-  grpc_slice value_slice = get_wire_value(elem, &huffman_prefix);
-  uint32_t len_val = (uint32_t)GRPC_SLICE_LENGTH(value_slice);
+  wire_value value = get_wire_value(elem, st->use_true_binary_metadata);
+  uint32_t len_val = (uint32_t)wire_value_length(value);
   uint32_t len_key_len = GRPC_CHTTP2_VARINT_LENGTH(len_key, 1);
   uint32_t len_val_len = GRPC_CHTTP2_VARINT_LENGTH(len_val, 1);
   GPR_ASSERT(len_key <= UINT32_MAX);
-  GPR_ASSERT(GRPC_SLICE_LENGTH(value_slice) <= UINT32_MAX);
+  GPR_ASSERT(wire_value_length(value) <= UINT32_MAX);
   *add_tiny_header_data(st, 1) = 0x00;
   GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00,
                            add_tiny_header_data(st, len_key_len), len_key_len);
   add_header_data(st, grpc_slice_ref_internal(GRPC_MDKEY(elem)));
-  GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix,
+  GRPC_CHTTP2_WRITE_VARINT(len_val, 1, value.huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, value_slice);
+  add_wire_value(st, value);
 }
 
 static void emit_advertise_table_size_change(grpc_chttp2_hpack_compressor *c,
@@ -595,23 +623,22 @@ void grpc_chttp2_hpack_compressor_set_max_table_size(
 
 void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
                                grpc_chttp2_hpack_compressor *c,
-                               uint32_t stream_id,
-                               grpc_metadata_batch *metadata, int is_eof,
-                               size_t max_frame_size,
-                               grpc_transport_one_way_stats *stats,
+                               grpc_metadata_batch *metadata,
+                               const grpc_encode_header_options *options,
                                grpc_slice_buffer *outbuf) {
   framer_state st;
   grpc_linked_mdelem *l;
   gpr_timespec deadline;
 
-  GPR_ASSERT(stream_id != 0);
+  GPR_ASSERT(options->stream_id != 0);
 
   st.seen_regular_header = 0;
-  st.stream_id = stream_id;
+  st.stream_id = options->stream_id;
   st.output = outbuf;
   st.is_first_frame = 1;
-  st.stats = stats;
-  st.max_frame_size = max_frame_size;
+  st.stats = options->stats;
+  st.max_frame_size = options->max_frame_size;
+  st.use_true_binary_metadata = options->use_true_binary_metadata;
 
   /* Encode a metadata batch; store the returned values, representing
      a metadata element that needs to be unreffed back into the metadata
@@ -630,5 +657,5 @@ void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
     deadline_enc(exec_ctx, c, deadline, &st);
   }
 
-  finish_frame(&st, 1, is_eof);
+  finish_frame(&st, 1, options->is_eof);
 }
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.h b/src/core/ext/transport/chttp2/transport/hpack_encoder.h
index 83ba5b1b3e..6ce3209604 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.h
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.h
@@ -90,11 +90,18 @@ void grpc_chttp2_hpack_compressor_set_max_table_size(
 void grpc_chttp2_hpack_compressor_set_max_usable_size(
     grpc_chttp2_hpack_compressor *c, uint32_t max_table_size);
 
+typedef struct {
+  uint32_t stream_id;
+  bool is_eof;
+  bool use_true_binary_metadata;
+  size_t max_frame_size;
+  grpc_transport_one_way_stats *stats;
+} grpc_encode_header_options;
+
 void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
-                               grpc_chttp2_hpack_compressor *c, uint32_t id,
-                               grpc_metadata_batch *metadata, int is_eof,
-                               size_t max_frame_size,
-                               grpc_transport_one_way_stats *stats,
+                               grpc_chttp2_hpack_compressor *c,
+                               grpc_metadata_batch *metadata,
+                               const grpc_encode_header_options *options,
                                grpc_slice_buffer *outbuf);
 
 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_ENCODER_H */
diff --git a/src/core/ext/transport/chttp2/transport/hpack_parser.c b/src/core/ext/transport/chttp2/transport/hpack_parser.c
index 5099d736bf..1846a85fc6 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_parser.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_parser.c
@@ -38,11 +38,6 @@
 #include <stddef.h>
 #include <string.h>
 
-/* This is here for grpc_is_binary_header
- * TODO(murgatroid99): Remove this
- */
-#include <grpc/grpc.h>
-
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/port_platform.h>
@@ -55,13 +50,11 @@
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/http2_errors.h"
 
-/* TODO(ctiller): remove before submission */
-#include "src/core/lib/slice/slice_string_helpers.h"
-
 extern int grpc_http_trace;
 
 typedef enum {
   NOT_BINARY,
+  BINARY_BEGIN,
   B64_BYTE0,
   B64_BYTE1,
   B64_BYTE2,
@@ -1325,6 +1318,19 @@ static grpc_error *append_string(grpc_exec_ctx *exec_ctx,
     case NOT_BINARY:
       append_bytes(str, cur, (size_t)(end - cur));
       return GRPC_ERROR_NONE;
+    case BINARY_BEGIN:
+      if (cur == end) {
+        p->binary = BINARY_BEGIN;
+        return GRPC_ERROR_NONE;
+      }
+      if (*cur == 0) {
+        /* 'true-binary' case */
+        ++cur;
+        p->binary = NOT_BINARY;
+        append_bytes(str, cur, (size_t)(end - cur));
+        return GRPC_ERROR_NONE;
+      }
+    /* fallthrough */
     b64_byte0:
     case B64_BYTE0:
       if (cur == end) {
@@ -1409,6 +1415,8 @@ static grpc_error *finish_str(grpc_exec_ctx *exec_ctx,
   switch ((binary_state)p->binary) {
     case NOT_BINARY:
       break;
+    case BINARY_BEGIN:
+      break;
     case B64_BYTE0:
       break;
     case B64_BYTE1:
@@ -1571,7 +1579,7 @@ static grpc_error *parse_value_string(grpc_exec_ctx *exec_ctx,
                                       const uint8_t *cur, const uint8_t *end,
                                       bool is_binary) {
   return begin_parse_string(exec_ctx, p, cur, end,
-                            is_binary ? B64_BYTE0 : NOT_BINARY, &p->value);
+                            is_binary ? BINARY_BEGIN : NOT_BINARY, &p->value);
 }
 
 static grpc_error *parse_value_string_with_indexed_key(
diff --git a/src/core/ext/transport/chttp2/transport/http2_settings.c b/src/core/ext/transport/chttp2/transport/http2_settings.c
new file mode 100644
index 0000000000..d4905107ef
--- /dev/null
+++ b/src/core/ext/transport/chttp2/transport/http2_settings.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Automatically generated by tools/codegen/core/gen_settings_ids.py
+ */
+
+#include "src/core/ext/transport/chttp2/transport/http2_settings.h"
+
+#include <grpc/support/useful.h>
+#include "src/core/lib/transport/http2_errors.h"
+
+const uint16_t grpc_setting_id_to_wire_id[] = {1, 2, 3, 4, 5, 6, 65027};
+
+bool grpc_wire_id_to_setting_id(uint32_t wire_id, grpc_chttp2_setting_id *out) {
+  uint32_t i = wire_id - 1;
+  uint32_t x = i % 256;
+  uint32_t y = i / 256;
+  uint32_t h = x;
+  switch (y) {
+    case 254:
+      h += 4;
+      break;
+  }
+  *out = (grpc_chttp2_setting_id)h;
+  return h < GPR_ARRAY_SIZE(grpc_setting_id_to_wire_id) &&
+         grpc_setting_id_to_wire_id[h] == wire_id;
+}
+
+const grpc_chttp2_setting_parameters
+    grpc_chttp2_settings_parameters[GRPC_CHTTP2_NUM_SETTINGS] = {
+        {"HEADER_TABLE_SIZE", 4096u, 0u, 4294967295u,
+         GRPC_CHTTP2_CLAMP_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
+        {"ENABLE_PUSH", 1u, 0u, 1u, GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE,
+         GRPC_HTTP2_PROTOCOL_ERROR},
+        {"MAX_CONCURRENT_STREAMS", 4294967295u, 0u, 4294967295u,
+         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
+        {"INITIAL_WINDOW_SIZE", 65535u, 0u, 2147483647u,
+         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE,
+         GRPC_HTTP2_FLOW_CONTROL_ERROR},
+        {"MAX_FRAME_SIZE", 16384u, 16384u, 16777215u,
+         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
+        {"MAX_HEADER_LIST_SIZE", 16777216u, 0u, 16777216u,
+         GRPC_CHTTP2_CLAMP_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
+        {"GRPC_ALLOW_TRUE_BINARY_METADATA", 0u, 0u, 1u,
+         GRPC_CHTTP2_CLAMP_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
+};
diff --git a/src/core/ext/transport/chttp2/transport/http2_settings.h b/src/core/ext/transport/chttp2/transport/http2_settings.h
new file mode 100644
index 0000000000..9781cdc989
--- /dev/null
+++ b/src/core/ext/transport/chttp2/transport/http2_settings.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Automatically generated by tools/codegen/core/gen_settings_ids.py
+ */
+
+#ifndef GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HTTP2_SETTINGS_H
+#define GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HTTP2_SETTINGS_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef enum {
+  GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE = 0,               /* wire id 1 */
+  GRPC_CHTTP2_SETTINGS_ENABLE_PUSH = 1,                     /* wire id 2 */
+  GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS = 2,          /* wire id 3 */
+  GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE = 3,             /* wire id 4 */
+  GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE = 4,                  /* wire id 5 */
+  GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE = 5,            /* wire id 6 */
+  GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA = 6, /* wire id 65027 */
+} grpc_chttp2_setting_id;
+
+#define GRPC_CHTTP2_NUM_SETTINGS 7
+extern const uint16_t grpc_setting_id_to_wire_id[];
+
+bool grpc_wire_id_to_setting_id(uint32_t wire_id, grpc_chttp2_setting_id *out);
+
+typedef enum {
+  GRPC_CHTTP2_CLAMP_INVALID_VALUE,
+  GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE
+} grpc_chttp2_invalid_value_behavior;
+
+typedef struct {
+  const char *name;
+  uint32_t default_value;
+  uint32_t min_value;
+  uint32_t max_value;
+  grpc_chttp2_invalid_value_behavior invalid_value_behavior;
+  uint32_t error_value;
+} grpc_chttp2_setting_parameters;
+
+extern const grpc_chttp2_setting_parameters
+    grpc_chttp2_settings_parameters[GRPC_CHTTP2_NUM_SETTINGS];
+
+#endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HTTP2_SETTINGS_H */
diff --git a/src/core/ext/transport/chttp2/transport/writing.c b/src/core/ext/transport/chttp2/transport/writing.c
index be41b3d186..ae9df175ff 100644
--- a/src/core/ext/transport/chttp2/transport/writing.c
+++ b/src/core/ext/transport/chttp2/transport/writing.c
@@ -219,10 +219,18 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
 
     /* send initial metadata if it's available */
     if (!sent_initial_metadata && s->send_initial_metadata) {
-      grpc_chttp2_encode_header(
-          exec_ctx, &t->hpack_compressor, s->id, s->send_initial_metadata, 0,
-          t->settings[GRPC_ACKED_SETTINGS][GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
-          &s->stats.outgoing, &t->outbuf);
+      grpc_encode_header_options hopt = {
+          .stream_id = s->id,
+          .is_eof = false,
+          .use_true_binary_metadata =
+              t->settings
+                  [GRPC_ACKED_SETTINGS]
+                  [GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA] != 0,
+          .max_frame_size = t->settings[GRPC_ACKED_SETTINGS]
+                                       [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
+          .stats = &s->stats.outgoing};
+      grpc_chttp2_encode_header(exec_ctx, &t->hpack_compressor,
+                                s->send_initial_metadata, &hopt, &t->outbuf);
       s->send_initial_metadata = NULL;
       s->sent_initial_metadata = true;
       sent_initial_metadata = true;
@@ -315,11 +323,21 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
           grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer, 0, true,
                                   &s->stats.outgoing, &t->outbuf);
         } else {
-          grpc_chttp2_encode_header(
-              exec_ctx, &t->hpack_compressor, s->id, s->send_trailing_metadata,
-              true, t->settings[GRPC_ACKED_SETTINGS]
-                               [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
-              &s->stats.outgoing, &t->outbuf);
+          grpc_encode_header_options hopt = {
+              .stream_id = s->id,
+              .is_eof = true,
+              .use_true_binary_metadata =
+                  t->settings
+                      [GRPC_ACKED_SETTINGS]
+                      [GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA] !=
+                  0,
+              .max_frame_size =
+                  t->settings[GRPC_ACKED_SETTINGS]
+                             [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
+              .stats = &s->stats.outgoing};
+          grpc_chttp2_encode_header(exec_ctx, &t->hpack_compressor,
+                                    s->send_trailing_metadata, &hopt,
+                                    &t->outbuf);
         }
         s->send_trailing_metadata = NULL;
         s->sent_trailing_metadata = true;
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 0d0a5fb088..7f810bd0b4 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -216,6 +216,7 @@ CORE_SOURCE_FILES = [
   'src/core/ext/transport/chttp2/transport/hpack_encoder.c',
   'src/core/ext/transport/chttp2/transport/hpack_parser.c',
   'src/core/ext/transport/chttp2/transport/hpack_table.c',
+  'src/core/ext/transport/chttp2/transport/http2_settings.c',
   'src/core/ext/transport/chttp2/transport/huffsyms.c',
   'src/core/ext/transport/chttp2/transport/incoming_metadata.c',
   'src/core/ext/transport/chttp2/transport/parsing.c',