1 files changed, 24 insertions, 15 deletions

diff --git a/src/core/surface/channel_create.c b/src/core/surface/channel_create.c
index 51d9130b63..aceb932742 100644
--- a/src/core/surface/channel_create.c
+++ b/src/core/surface/channel_create.c
@@ -37,6 +37,8 @@
 #include <string.h>
 
 #include <grpc/support/alloc.h>
+#include <grpc/support/slice.h>
+#include <grpc/support/slice_buffer.h>
 
 #include "src/core/census/grpc_filter.h"
 #include "src/core/channel/channel_args.h"
@@ -56,11 +58,11 @@ typedef struct {
   grpc_closure *notify;
   grpc_connect_in_args args;
   grpc_connect_out_args *result;
+  grpc_closure initial_string_sent;
+  gpr_slice_buffer initial_string_buffer;
 
   grpc_endpoint *tcp;
 
-  grpc_mdctx *mdctx;
-
   grpc_closure connected;
 } connector;
 
@@ -72,18 +74,33 @@ static void connector_ref(grpc_connector *con) {
 static void connector_unref(grpc_exec_ctx *exec_ctx, grpc_connector *con) {
   connector *c = (connector *)con;
   if (gpr_unref(&c->refs)) {
-    grpc_mdctx_unref(c->mdctx);
+    /* c->initial_string_buffer does not need to be destroyed */
     gpr_free(c);
   }
 }
 
+static void on_initial_connect_string_sent(grpc_exec_ctx *exec_ctx, void *arg,
+                                           int success) {
+  connector_unref(exec_ctx, arg);
+}
+
 static void connected(grpc_exec_ctx *exec_ctx, void *arg, int success) {
   connector *c = arg;
   grpc_closure *notify;
   grpc_endpoint *tcp = c->tcp;
   if (tcp != NULL) {
-    c->result->transport = grpc_create_chttp2_transport(
-        exec_ctx, c->args.channel_args, tcp, c->mdctx, 1);
+    if (!GPR_SLICE_IS_EMPTY(c->args.initial_connect_string)) {
+      grpc_closure_init(&c->initial_string_sent, on_initial_connect_string_sent,
+                        c);
+      gpr_slice_buffer_init(&c->initial_string_buffer);
+      gpr_slice_buffer_add(&c->initial_string_buffer,
+                           c->args.initial_connect_string);
+      connector_ref(arg);
+      grpc_endpoint_write(exec_ctx, tcp, &c->initial_string_buffer,
+                          &c->initial_string_sent);
+    }
+    c->result->transport =
+        grpc_create_chttp2_transport(exec_ctx, c->args.channel_args, tcp, 1);
     grpc_chttp2_transport_start_reading(exec_ctx, c->result->transport, NULL,
                                         0);
     GPR_ASSERT(c->result->transport);
@@ -123,7 +140,6 @@ static const grpc_connector_vtable connector_vtable = {
 typedef struct {
   grpc_subchannel_factory base;
   gpr_refcount refs;
-  grpc_mdctx *mdctx;
   grpc_channel_args *merge_args;
   grpc_channel *master;
 } subchannel_factory;
@@ -139,7 +155,6 @@ static void subchannel_factory_unref(grpc_exec_ctx *exec_ctx,
   if (gpr_unref(&f->refs)) {
     GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, f->master, "subchannel_factory");
     grpc_channel_args_destroy(f->merge_args);
-    grpc_mdctx_unref(f->mdctx);
     gpr_free(f);
   }
 }
@@ -154,10 +169,7 @@ static grpc_subchannel *subchannel_factory_create_subchannel(
   grpc_subchannel *s;
   memset(c, 0, sizeof(*c));
   c->base.vtable = &connector_vtable;
-  c->mdctx = f->mdctx;
-  grpc_mdctx_ref(c->mdctx);
   gpr_ref_init(&c->refs, 1);
-  args->mdctx = f->mdctx;
   args->args = final_args;
   args->master = f->master;
   s = grpc_subchannel_create(&c->base, args);
@@ -182,7 +194,6 @@ grpc_channel *grpc_insecure_channel_create(const char *target,
   const grpc_channel_filter *filters[MAX_FILTERS];
   grpc_resolver *resolver;
   subchannel_factory *f;
-  grpc_mdctx *mdctx = grpc_mdctx_create();
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   size_t n = 0;
   GRPC_API_TRACE(
@@ -196,14 +207,12 @@ grpc_channel *grpc_insecure_channel_create(const char *target,
   filters[n++] = &grpc_client_channel_filter;
   GPR_ASSERT(n <= MAX_FILTERS);
 
-  channel = grpc_channel_create_from_filters(&exec_ctx, target, filters, n,
-                                             args, mdctx, 1);
+  channel =
+      grpc_channel_create_from_filters(&exec_ctx, target, filters, n, args, 1);
 
   f = gpr_malloc(sizeof(*f));
   f->base.vtable = &subchannel_factory_vtable;
   gpr_ref_init(&f->refs, 1);
-  grpc_mdctx_ref(mdctx);
-  f->mdctx = mdctx;
   f->merge_args = grpc_channel_args_copy(args);
   f->master = channel;
   GRPC_CHANNEL_INTERNAL_REF(f->master, "subchannel_factory");