Merge github.com:grpc/grpc into 44

14 files changed, 1174 insertions, 68 deletions

diff --git a/src/core/client_config/lb_policies/load_balancer_api.c b/src/core/client_config/lb_policies/load_balancer_api.c
new file mode 100644
index 0000000000..a6b5785fe4
--- /dev/null
+++ b/src/core/client_config/lb_policies/load_balancer_api.c
@@ -0,0 +1,163 @@
+/*
+ *
+ * Copyright 2016, 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.
+ *
+ */
+
+#include "src/core/client_config/lb_policies/load_balancer_api.h"
+#include "third_party/nanopb/pb_decode.h"
+#include "third_party/nanopb/pb_encode.h"
+
+#include <grpc/support/alloc.h>
+
+typedef struct decode_serverlist_arg {
+  int first_pass;
+  int i;
+  size_t num_servers;
+  grpc_grpclb_server **servers;
+} decode_serverlist_arg;
+
+/* invoked once for every Server in ServerList */
+static bool decode_serverlist(pb_istream_t *stream, const pb_field_t *field,
+                              void **arg) {
+  decode_serverlist_arg *dec_arg = *arg;
+  if (dec_arg->first_pass != 0) { /* first pass */
+    grpc_grpclb_server server;
+    if (!pb_decode(stream, grpc_lb_v0_Server_fields, &server)) {
+      return false;
+    }
+    dec_arg->num_servers++;
+  } else { /* second pass */
+    grpc_grpclb_server *server = gpr_malloc(sizeof(grpc_grpclb_server));
+    GPR_ASSERT(dec_arg->num_servers > 0);
+    if (dec_arg->i == 0) { /* first iteration of second pass */
+      dec_arg->servers =
+          gpr_malloc(sizeof(grpc_grpclb_server *) * dec_arg->num_servers);
+    }
+    if (!pb_decode(stream, grpc_lb_v0_Server_fields, server)) {
+      return false;
+    }
+    dec_arg->servers[dec_arg->i++] = server;
+  }
+
+  return true;
+}
+
+grpc_grpclb_request *grpc_grpclb_request_create(const char *lb_service_name) {
+  grpc_grpclb_request *req = gpr_malloc(sizeof(grpc_grpclb_request));
+
+  req->has_client_stats = 0; /* TODO(dgq): add support for stats once defined */
+  req->has_initial_request = 1;
+  req->initial_request.has_name = 1;
+  strncpy(req->initial_request.name, lb_service_name,
+          GRPC_GRPCLB_SERVICE_NAME_MAX_LENGTH);
+  return req;
+}
+
+gpr_slice grpc_grpclb_request_encode(const grpc_grpclb_request *request) {
+  size_t encoded_length;
+  pb_ostream_t sizestream;
+  pb_ostream_t outputstream;
+  gpr_slice slice;
+  memset(&sizestream, 0, sizeof(pb_ostream_t));
+  pb_encode(&sizestream, grpc_lb_v0_LoadBalanceRequest_fields, request);
+  encoded_length = sizestream.bytes_written;
+
+  slice = gpr_slice_malloc(encoded_length);
+  outputstream =
+      pb_ostream_from_buffer(GPR_SLICE_START_PTR(slice), encoded_length);
+  GPR_ASSERT(pb_encode(&outputstream, grpc_lb_v0_LoadBalanceRequest_fields,
+                       request) != 0);
+  return slice;
+}
+
+void grpc_grpclb_request_destroy(grpc_grpclb_request *request) {
+  gpr_free(request);
+}
+
+grpc_grpclb_response *grpc_grpclb_response_parse(gpr_slice encoded_response) {
+  bool status;
+  pb_istream_t stream =
+      pb_istream_from_buffer(GPR_SLICE_START_PTR(encoded_response),
+                             GPR_SLICE_LENGTH(encoded_response));
+  grpc_grpclb_response *res = gpr_malloc(sizeof(grpc_grpclb_response));
+  memset(res, 0, sizeof(*res));
+  status = pb_decode(&stream, grpc_lb_v0_LoadBalanceResponse_fields, res);
+  GPR_ASSERT(status == true);
+  return res;
+}
+
+grpc_grpclb_serverlist *grpc_grpclb_response_parse_serverlist(
+    gpr_slice encoded_response) {
+  grpc_grpclb_serverlist *sl = gpr_malloc(sizeof(grpc_grpclb_serverlist));
+  bool status;
+  decode_serverlist_arg arg;
+  pb_istream_t stream =
+      pb_istream_from_buffer(GPR_SLICE_START_PTR(encoded_response),
+                             GPR_SLICE_LENGTH(encoded_response));
+  pb_istream_t stream_at_start = stream;
+  grpc_grpclb_response *res = gpr_malloc(sizeof(grpc_grpclb_response));
+  memset(res, 0, sizeof(*res));
+  memset(&arg, 0, sizeof(decode_serverlist_arg));
+
+  res->server_list.servers.funcs.decode = decode_serverlist;
+  res->server_list.servers.arg = &arg;
+  arg.first_pass = 1;
+  status = pb_decode(&stream, grpc_lb_v0_LoadBalanceResponse_fields, res);
+  GPR_ASSERT(status == true);
+  GPR_ASSERT(arg.num_servers > 0);
+
+  arg.first_pass = 0;
+  status =
+      pb_decode(&stream_at_start, grpc_lb_v0_LoadBalanceResponse_fields, res);
+  GPR_ASSERT(status == true);
+  GPR_ASSERT(arg.servers != NULL);
+
+  sl->num_servers = arg.num_servers;
+  sl->servers = arg.servers;
+  if (res->server_list.has_expiration_interval) {
+    sl->expiration_interval = res->server_list.expiration_interval;
+  }
+  grpc_grpclb_response_destroy(res);
+  return sl;
+}
+
+void grpc_grpclb_destroy_serverlist(grpc_grpclb_serverlist *serverlist) {
+  size_t i;
+  for (i = 0; i < serverlist->num_servers; i++) {
+    gpr_free(serverlist->servers[i]);
+  }
+  gpr_free(serverlist->servers);
+  gpr_free(serverlist);
+}
+
+void grpc_grpclb_response_destroy(grpc_grpclb_response *response) {
+  gpr_free(response);
+}
diff --git a/src/core/client_config/lb_policies/load_balancer_api.h b/src/core/client_config/lb_policies/load_balancer_api.h
new file mode 100644
index 0000000000..4dbe1d6c22
--- /dev/null
+++ b/src/core/client_config/lb_policies/load_balancer_api.h
@@ -0,0 +1,85 @@
+/*
+ *
+ * Copyright 2016, 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.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_CLIENT_CONFIG_LB_POLICIES_LOAD_BALANCER_API_H
+#define GRPC_INTERNAL_CORE_CLIENT_CONFIG_LB_POLICIES_LOAD_BALANCER_API_H
+
+#include <grpc/support/slice_buffer.h>
+
+#include "src/core/client_config/lb_policy_factory.h"
+#include "src/core/proto/grpc/lb/v0/load_balancer.pb.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define GRPC_GRPCLB_SERVICE_NAME_MAX_LENGTH 128
+
+typedef grpc_lb_v0_LoadBalanceRequest grpc_grpclb_request;
+typedef grpc_lb_v0_LoadBalanceResponse grpc_grpclb_response;
+typedef grpc_lb_v0_Server grpc_grpclb_server;
+typedef grpc_lb_v0_Duration grpc_grpclb_duration;
+typedef struct grpc_grpclb_serverlist {
+  grpc_grpclb_server **servers;
+  size_t num_servers;
+  grpc_grpclb_duration expiration_interval;
+} grpc_grpclb_serverlist;
+
+/** Create a request for a gRPC LB service under \a lb_service_name */
+grpc_grpclb_request *grpc_grpclb_request_create(const char *lb_service_name);
+
+/** Protocol Buffers v3-encode \a request */
+gpr_slice grpc_grpclb_request_encode(const grpc_grpclb_request *request);
+
+/** Destroy \a request */
+void grpc_grpclb_request_destroy(grpc_grpclb_request *request);
+
+/** Parse (ie, decode) the bytes in \a encoded_response as a \a
+ * grpc_grpclb_response */
+grpc_grpclb_response *grpc_grpclb_response_parse(gpr_slice encoded_response);
+
+/** Destroy \a serverlist */
+void grpc_grpclb_destroy_serverlist(grpc_grpclb_serverlist *serverlist);
+
+/** Parse the list of servers from an encoded \a grpc_grpclb_response */
+grpc_grpclb_serverlist *grpc_grpclb_response_parse_serverlist(
+    gpr_slice encoded_response);
+
+/** Destroy \a response */
+void grpc_grpclb_response_destroy(grpc_grpclb_response *response);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_LB_POLICIES_LOAD_BALANCER_API_H */
diff --git a/src/core/proto/grpc/lb/v0/load_balancer.pb.c b/src/core/proto/grpc/lb/v0/load_balancer.pb.c
new file mode 100644
index 0000000000..59aae30cff
--- /dev/null
+++ b/src/core/proto/grpc/lb/v0/load_balancer.pb.c
@@ -0,0 +1,119 @@
+/*
+ *
+ * Copyright 2016, 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 nanopb constant definitions */
+/* Generated by nanopb-0.3.5-dev */
+
+#include "src/core/proto/grpc/lb/v0/load_balancer.pb.h"
+
+#if PB_PROTO_HEADER_VERSION != 30
+#error Regenerate this file with the current version of nanopb generator.
+#endif
+
+
+
+const pb_field_t grpc_lb_v0_Duration_fields[3] = {
+    PB_FIELD(  1, INT64   , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_Duration, seconds, seconds, 0),
+    PB_FIELD(  2, INT32   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_Duration, nanos, seconds, 0),
+    PB_LAST_FIELD
+};
+
+const pb_field_t grpc_lb_v0_LoadBalanceRequest_fields[3] = {
+    PB_FIELD(  1, MESSAGE , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_LoadBalanceRequest, initial_request, initial_request, &grpc_lb_v0_InitialLoadBalanceRequest_fields),
+    PB_FIELD(  2, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_LoadBalanceRequest, client_stats, initial_request, &grpc_lb_v0_ClientStats_fields),
+    PB_LAST_FIELD
+};
+
+const pb_field_t grpc_lb_v0_InitialLoadBalanceRequest_fields[2] = {
+    PB_FIELD(  1, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_InitialLoadBalanceRequest, name, name, 0),
+    PB_LAST_FIELD
+};
+
+const pb_field_t grpc_lb_v0_ClientStats_fields[4] = {
+    PB_FIELD(  1, INT64   , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_ClientStats, total_requests, total_requests, 0),
+    PB_FIELD(  2, INT64   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_ClientStats, client_rpc_errors, total_requests, 0),
+    PB_FIELD(  3, INT64   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_ClientStats, dropped_requests, client_rpc_errors, 0),
+    PB_LAST_FIELD
+};
+
+const pb_field_t grpc_lb_v0_LoadBalanceResponse_fields[3] = {
+    PB_FIELD(  1, MESSAGE , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_LoadBalanceResponse, initial_response, initial_response, &grpc_lb_v0_InitialLoadBalanceResponse_fields),
+    PB_FIELD(  2, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_LoadBalanceResponse, server_list, initial_response, &grpc_lb_v0_ServerList_fields),
+    PB_LAST_FIELD
+};
+
+const pb_field_t grpc_lb_v0_InitialLoadBalanceResponse_fields[4] = {
+    PB_FIELD(  1, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_InitialLoadBalanceResponse, client_config, client_config, 0),
+    PB_FIELD(  2, STRING  , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_InitialLoadBalanceResponse, load_balancer_delegate, client_config, 0),
+    PB_FIELD(  3, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_InitialLoadBalanceResponse, client_stats_report_interval, load_balancer_delegate, &grpc_lb_v0_Duration_fields),
+    PB_LAST_FIELD
+};
+
+const pb_field_t grpc_lb_v0_ServerList_fields[3] = {
+    PB_FIELD(  1, MESSAGE , REPEATED, CALLBACK, FIRST, grpc_lb_v0_ServerList, servers, servers, &grpc_lb_v0_Server_fields),
+    PB_FIELD(  3, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_ServerList, expiration_interval, servers, &grpc_lb_v0_Duration_fields),
+    PB_LAST_FIELD
+};
+
+const pb_field_t grpc_lb_v0_Server_fields[5] = {
+    PB_FIELD(  1, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_Server, ip_address, ip_address, 0),
+    PB_FIELD(  2, INT32   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_Server, port, ip_address, 0),
+    PB_FIELD(  3, BYTES   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_Server, load_balance_token, port, 0),
+    PB_FIELD(  4, BOOL    , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_Server, drop_request, load_balance_token, 0),
+    PB_LAST_FIELD
+};
+
+
+/* Check that field information fits in pb_field_t */
+#if !defined(PB_FIELD_32BIT)
+/* If you get an error here, it means that you need to define PB_FIELD_32BIT
+ * compile-time option. You can do that in pb.h or on compiler command line.
+ * 
+ * The reason you need to do this is that some of your messages contain tag
+ * numbers or field sizes that are larger than what can fit in 8 or 16 bit
+ * field descriptors.
+ */
+PB_STATIC_ASSERT((pb_membersize(grpc_lb_v0_LoadBalanceRequest, initial_request) < 65536 && pb_membersize(grpc_lb_v0_LoadBalanceRequest, client_stats) < 65536 && pb_membersize(grpc_lb_v0_LoadBalanceResponse, initial_response) < 65536 && pb_membersize(grpc_lb_v0_LoadBalanceResponse, server_list) < 65536 && pb_membersize(grpc_lb_v0_InitialLoadBalanceResponse, client_stats_report_interval) < 65536 && pb_membersize(grpc_lb_v0_ServerList, servers) < 65536 && pb_membersize(grpc_lb_v0_ServerList, expiration_interval) < 65536), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_grpc_lb_v0_Duration_grpc_lb_v0_LoadBalanceRequest_grpc_lb_v0_InitialLoadBalanceRequest_grpc_lb_v0_ClientStats_grpc_lb_v0_LoadBalanceResponse_grpc_lb_v0_InitialLoadBalanceResponse_grpc_lb_v0_ServerList_grpc_lb_v0_Server)
+#endif
+
+#if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
+/* If you get an error here, it means that you need to define PB_FIELD_16BIT
+ * compile-time option. You can do that in pb.h or on compiler command line.
+ * 
+ * The reason you need to do this is that some of your messages contain tag
+ * numbers or field sizes that are larger than what can fit in the default
+ * 8 bit descriptors.
+ */
+PB_STATIC_ASSERT((pb_membersize(grpc_lb_v0_LoadBalanceRequest, initial_request) < 256 && pb_membersize(grpc_lb_v0_LoadBalanceRequest, client_stats) < 256 && pb_membersize(grpc_lb_v0_LoadBalanceResponse, initial_response) < 256 && pb_membersize(grpc_lb_v0_LoadBalanceResponse, server_list) < 256 && pb_membersize(grpc_lb_v0_InitialLoadBalanceResponse, client_stats_report_interval) < 256 && pb_membersize(grpc_lb_v0_ServerList, servers) < 256 && pb_membersize(grpc_lb_v0_ServerList, expiration_interval) < 256), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_grpc_lb_v0_Duration_grpc_lb_v0_LoadBalanceRequest_grpc_lb_v0_InitialLoadBalanceRequest_grpc_lb_v0_ClientStats_grpc_lb_v0_LoadBalanceResponse_grpc_lb_v0_InitialLoadBalanceResponse_grpc_lb_v0_ServerList_grpc_lb_v0_Server)
+#endif
+
+
diff --git a/src/core/proto/grpc/lb/v0/load_balancer.pb.h b/src/core/proto/grpc/lb/v0/load_balancer.pb.h
new file mode 100644
index 0000000000..3599f881bb
--- /dev/null
+++ b/src/core/proto/grpc/lb/v0/load_balancer.pb.h
@@ -0,0 +1,182 @@
+/*
+ *
+ * Copyright 2016, 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 nanopb header */
+/* Generated by nanopb-0.3.5-dev */
+
+#ifndef PB_LOAD_BALANCER_PB_H_INCLUDED
+#define PB_LOAD_BALANCER_PB_H_INCLUDED
+#include "third_party/nanopb/pb.h"
+#if PB_PROTO_HEADER_VERSION != 30
+#error Regenerate this file with the current version of nanopb generator.
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Struct definitions */
+typedef struct _grpc_lb_v0_ClientStats {
+    bool has_total_requests;
+    int64_t total_requests;
+    bool has_client_rpc_errors;
+    int64_t client_rpc_errors;
+    bool has_dropped_requests;
+    int64_t dropped_requests;
+} grpc_lb_v0_ClientStats;
+
+typedef struct _grpc_lb_v0_Duration {
+    bool has_seconds;
+    int64_t seconds;
+    bool has_nanos;
+    int32_t nanos;
+} grpc_lb_v0_Duration;
+
+typedef struct _grpc_lb_v0_InitialLoadBalanceRequest {
+    bool has_name;
+    char name[128];
+} grpc_lb_v0_InitialLoadBalanceRequest;
+
+typedef PB_BYTES_ARRAY_T(64) grpc_lb_v0_Server_load_balance_token_t;
+typedef struct _grpc_lb_v0_Server {
+    bool has_ip_address;
+    char ip_address[46];
+    bool has_port;
+    int32_t port;
+    bool has_load_balance_token;
+    grpc_lb_v0_Server_load_balance_token_t load_balance_token;
+    bool has_drop_request;
+    bool drop_request;
+} grpc_lb_v0_Server;
+
+typedef struct _grpc_lb_v0_InitialLoadBalanceResponse {
+    bool has_client_config;
+    char client_config[64];
+    bool has_load_balancer_delegate;
+    char load_balancer_delegate[64];
+    bool has_client_stats_report_interval;
+    grpc_lb_v0_Duration client_stats_report_interval;
+} grpc_lb_v0_InitialLoadBalanceResponse;
+
+typedef struct _grpc_lb_v0_LoadBalanceRequest {
+    bool has_initial_request;
+    grpc_lb_v0_InitialLoadBalanceRequest initial_request;
+    bool has_client_stats;
+    grpc_lb_v0_ClientStats client_stats;
+} grpc_lb_v0_LoadBalanceRequest;
+
+typedef struct _grpc_lb_v0_ServerList {
+    pb_callback_t servers;
+    bool has_expiration_interval;
+    grpc_lb_v0_Duration expiration_interval;
+} grpc_lb_v0_ServerList;
+
+typedef struct _grpc_lb_v0_LoadBalanceResponse {
+    bool has_initial_response;
+    grpc_lb_v0_InitialLoadBalanceResponse initial_response;
+    bool has_server_list;
+    grpc_lb_v0_ServerList server_list;
+} grpc_lb_v0_LoadBalanceResponse;
+
+/* Default values for struct fields */
+
+/* Initializer values for message structs */
+#define grpc_lb_v0_Duration_init_default         {false, 0, false, 0}
+#define grpc_lb_v0_LoadBalanceRequest_init_default {false, grpc_lb_v0_InitialLoadBalanceRequest_init_default, false, grpc_lb_v0_ClientStats_init_default}
+#define grpc_lb_v0_InitialLoadBalanceRequest_init_default {false, ""}
+#define grpc_lb_v0_ClientStats_init_default      {false, 0, false, 0, false, 0}
+#define grpc_lb_v0_LoadBalanceResponse_init_default {false, grpc_lb_v0_InitialLoadBalanceResponse_init_default, false, grpc_lb_v0_ServerList_init_default}
+#define grpc_lb_v0_InitialLoadBalanceResponse_init_default {false, "", false, "", false, grpc_lb_v0_Duration_init_default}
+#define grpc_lb_v0_ServerList_init_default       {{{NULL}, NULL}, false, grpc_lb_v0_Duration_init_default}
+#define grpc_lb_v0_Server_init_default           {false, "", false, 0, false, {0, {0}}, false, 0}
+#define grpc_lb_v0_Duration_init_zero            {false, 0, false, 0}
+#define grpc_lb_v0_LoadBalanceRequest_init_zero  {false, grpc_lb_v0_InitialLoadBalanceRequest_init_zero, false, grpc_lb_v0_ClientStats_init_zero}
+#define grpc_lb_v0_InitialLoadBalanceRequest_init_zero {false, ""}
+#define grpc_lb_v0_ClientStats_init_zero         {false, 0, false, 0, false, 0}
+#define grpc_lb_v0_LoadBalanceResponse_init_zero {false, grpc_lb_v0_InitialLoadBalanceResponse_init_zero, false, grpc_lb_v0_ServerList_init_zero}
+#define grpc_lb_v0_InitialLoadBalanceResponse_init_zero {false, "", false, "", false, grpc_lb_v0_Duration_init_zero}
+#define grpc_lb_v0_ServerList_init_zero          {{{NULL}, NULL}, false, grpc_lb_v0_Duration_init_zero}
+#define grpc_lb_v0_Server_init_zero              {false, "", false, 0, false, {0, {0}}, false, 0}
+
+/* Field tags (for use in manual encoding/decoding) */
+#define grpc_lb_v0_ClientStats_total_requests_tag 1
+#define grpc_lb_v0_ClientStats_client_rpc_errors_tag 2
+#define grpc_lb_v0_ClientStats_dropped_requests_tag 3
+#define grpc_lb_v0_Duration_seconds_tag          1
+#define grpc_lb_v0_Duration_nanos_tag            2
+#define grpc_lb_v0_InitialLoadBalanceRequest_name_tag 1
+#define grpc_lb_v0_Server_ip_address_tag         1
+#define grpc_lb_v0_Server_port_tag               2
+#define grpc_lb_v0_Server_load_balance_token_tag 3
+#define grpc_lb_v0_Server_drop_request_tag       4
+#define grpc_lb_v0_InitialLoadBalanceResponse_client_config_tag 1
+#define grpc_lb_v0_InitialLoadBalanceResponse_load_balancer_delegate_tag 2
+#define grpc_lb_v0_InitialLoadBalanceResponse_client_stats_report_interval_tag 3
+#define grpc_lb_v0_LoadBalanceRequest_initial_request_tag 1
+#define grpc_lb_v0_LoadBalanceRequest_client_stats_tag 2
+#define grpc_lb_v0_ServerList_servers_tag        1
+#define grpc_lb_v0_ServerList_expiration_interval_tag 3
+#define grpc_lb_v0_LoadBalanceResponse_initial_response_tag 1
+#define grpc_lb_v0_LoadBalanceResponse_server_list_tag 2
+
+/* Struct field encoding specification for nanopb */
+extern const pb_field_t grpc_lb_v0_Duration_fields[3];
+extern const pb_field_t grpc_lb_v0_LoadBalanceRequest_fields[3];
+extern const pb_field_t grpc_lb_v0_InitialLoadBalanceRequest_fields[2];
+extern const pb_field_t grpc_lb_v0_ClientStats_fields[4];
+extern const pb_field_t grpc_lb_v0_LoadBalanceResponse_fields[3];
+extern const pb_field_t grpc_lb_v0_InitialLoadBalanceResponse_fields[4];
+extern const pb_field_t grpc_lb_v0_ServerList_fields[3];
+extern const pb_field_t grpc_lb_v0_Server_fields[5];
+
+/* Maximum encoded size of messages (where known) */
+#define grpc_lb_v0_Duration_size                 22
+#define grpc_lb_v0_LoadBalanceRequest_size       169
+#define grpc_lb_v0_InitialLoadBalanceRequest_size 131
+#define grpc_lb_v0_ClientStats_size              33
+#define grpc_lb_v0_LoadBalanceResponse_size      (165 + grpc_lb_v0_ServerList_size)
+#define grpc_lb_v0_InitialLoadBalanceResponse_size 156
+#define grpc_lb_v0_Server_size                   127
+
+/* Message IDs (where set with "msgid" option) */
+#ifdef PB_MSGID
+
+#define LOAD_BALANCER_MESSAGES \
+
+
+#endif
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif
diff --git a/src/csharp/Grpc.IntegrationTesting/Control.cs b/src/csharp/Grpc.IntegrationTesting/Control.cs
index b90243c2bd..291bc75397 100644
--- a/src/csharp/Grpc.IntegrationTesting/Control.cs
+++ b/src/csharp/Grpc.IntegrationTesting/Control.cs
@@ -38,7 +38,7 @@ namespace Grpc.Testing {
             "LmdycGMudGVzdGluZy5EZXRlcm1pbmlzdGljUGFyYW1zSAASLAoGcGFyZXRv",
             "GAUgASgLMhouZ3JwYy50ZXN0aW5nLlBhcmV0b1BhcmFtc0gAQgYKBGxvYWQi",
             "QwoOU2VjdXJpdHlQYXJhbXMSEwoLdXNlX3Rlc3RfY2EYASABKAgSHAoUc2Vy",
-            "dmVyX2hvc3Rfb3ZlcnJpZGUYAiABKAkirwMKDENsaWVudENvbmZpZxIWCg5z",
+            "dmVyX2hvc3Rfb3ZlcnJpZGUYAiABKAki1gMKDENsaWVudENvbmZpZxIWCg5z",
             "ZXJ2ZXJfdGFyZ2V0cxgBIAMoCRItCgtjbGllbnRfdHlwZRgCIAEoDjIYLmdy",
             "cGMudGVzdGluZy5DbGllbnRUeXBlEjUKD3NlY3VyaXR5X3BhcmFtcxgDIAEo",
             "CzIcLmdycGMudGVzdGluZy5TZWN1cml0eVBhcmFtcxIkChxvdXRzdGFuZGlu",
@@ -48,24 +48,27 @@ namespace Grpc.Testing {
             "GAogASgLMhguZ3JwYy50ZXN0aW5nLkxvYWRQYXJhbXMSMwoOcGF5bG9hZF9j",
             "b25maWcYCyABKAsyGy5ncnBjLnRlc3RpbmcuUGF5bG9hZENvbmZpZxI3ChBo",
             "aXN0b2dyYW1fcGFyYW1zGAwgASgLMh0uZ3JwYy50ZXN0aW5nLkhpc3RvZ3Jh",
-            "bVBhcmFtcyI4CgxDbGllbnRTdGF0dXMSKAoFc3RhdHMYASABKAsyGS5ncnBj",
-            "LnRlc3RpbmcuQ2xpZW50U3RhdHMiFQoETWFyaxINCgVyZXNldBgBIAEoCCJo",
-            "CgpDbGllbnRBcmdzEisKBXNldHVwGAEgASgLMhouZ3JwYy50ZXN0aW5nLkNs",
-            "aWVudENvbmZpZ0gAEiIKBG1hcmsYAiABKAsyEi5ncnBjLnRlc3RpbmcuTWFy",
-            "a0gAQgkKB2FyZ3R5cGUi9wEKDFNlcnZlckNvbmZpZxItCgtzZXJ2ZXJfdHlw",
-            "ZRgBIAEoDjIYLmdycGMudGVzdGluZy5TZXJ2ZXJUeXBlEjUKD3NlY3VyaXR5",
-            "X3BhcmFtcxgCIAEoCzIcLmdycGMudGVzdGluZy5TZWN1cml0eVBhcmFtcxIM",
-            "CgRob3N0GAMgASgJEgwKBHBvcnQYBCABKAUSHAoUYXN5bmNfc2VydmVyX3Ro",
-            "cmVhZHMYByABKAUSEgoKY29yZV9saW1pdBgIIAEoBRIzCg5wYXlsb2FkX2Nv",
-            "bmZpZxgJIAEoCzIbLmdycGMudGVzdGluZy5QYXlsb2FkQ29uZmlnImgKClNl",
-            "cnZlckFyZ3MSKwoFc2V0dXAYASABKAsyGi5ncnBjLnRlc3RpbmcuU2VydmVy",
-            "Q29uZmlnSAASIgoEbWFyaxgCIAEoCzISLmdycGMudGVzdGluZy5NYXJrSABC",
-            "CQoHYXJndHlwZSJVCgxTZXJ2ZXJTdGF0dXMSKAoFc3RhdHMYASABKAsyGS5n",
-            "cnBjLnRlc3RpbmcuU2VydmVyU3RhdHMSDAoEcG9ydBgCIAEoBRINCgVjb3Jl",
-            "cxgDIAEoBSovCgpDbGllbnRUeXBlEg8KC1NZTkNfQ0xJRU5UEAASEAoMQVNZ",
-            "TkNfQ0xJRU5UEAEqLwoKU2VydmVyVHlwZRIPCgtTWU5DX1NFUlZFUhAAEhAK",
-            "DEFTWU5DX1NFUlZFUhABKiMKB1JwY1R5cGUSCQoFVU5BUlkQABINCglTVFJF",
-            "QU1JTkcQAWIGcHJvdG8z"));
+            "bVBhcmFtcxIRCgljb3JlX2xpc3QYDSADKAUSEgoKY29yZV9saW1pdBgOIAEo",
+            "BSI4CgxDbGllbnRTdGF0dXMSKAoFc3RhdHMYASABKAsyGS5ncnBjLnRlc3Rp",
+            "bmcuQ2xpZW50U3RhdHMiFQoETWFyaxINCgVyZXNldBgBIAEoCCJoCgpDbGll",
+            "bnRBcmdzEisKBXNldHVwGAEgASgLMhouZ3JwYy50ZXN0aW5nLkNsaWVudENv",
+            "bmZpZ0gAEiIKBG1hcmsYAiABKAsyEi5ncnBjLnRlc3RpbmcuTWFya0gAQgkK",
+            "B2FyZ3R5cGUi/AEKDFNlcnZlckNvbmZpZxItCgtzZXJ2ZXJfdHlwZRgBIAEo",
+            "DjIYLmdycGMudGVzdGluZy5TZXJ2ZXJUeXBlEjUKD3NlY3VyaXR5X3BhcmFt",
+            "cxgCIAEoCzIcLmdycGMudGVzdGluZy5TZWN1cml0eVBhcmFtcxIMCgRwb3J0",
+            "GAQgASgFEhwKFGFzeW5jX3NlcnZlcl90aHJlYWRzGAcgASgFEhIKCmNvcmVf",
+            "bGltaXQYCCABKAUSMwoOcGF5bG9hZF9jb25maWcYCSABKAsyGy5ncnBjLnRl",
+            "c3RpbmcuUGF5bG9hZENvbmZpZxIRCgljb3JlX2xpc3QYCiADKAUiaAoKU2Vy",
+            "dmVyQXJncxIrCgVzZXR1cBgBIAEoCzIaLmdycGMudGVzdGluZy5TZXJ2ZXJD",
+            "b25maWdIABIiCgRtYXJrGAIgASgLMhIuZ3JwYy50ZXN0aW5nLk1hcmtIAEIJ",
+            "Cgdhcmd0eXBlIlUKDFNlcnZlclN0YXR1cxIoCgVzdGF0cxgBIAEoCzIZLmdy",
+            "cGMudGVzdGluZy5TZXJ2ZXJTdGF0cxIMCgRwb3J0GAIgASgFEg0KBWNvcmVz",
+            "GAMgASgFIg0KC0NvcmVSZXF1ZXN0Ih0KDENvcmVSZXNwb25zZRINCgVjb3Jl",
+            "cxgBIAEoBSIGCgRWb2lkKi8KCkNsaWVudFR5cGUSDwoLU1lOQ19DTElFTlQQ",
+            "ABIQCgxBU1lOQ19DTElFTlQQASpJCgpTZXJ2ZXJUeXBlEg8KC1NZTkNfU0VS",
+            "VkVSEAASEAoMQVNZTkNfU0VSVkVSEAESGAoUQVNZTkNfR0VORVJJQ19TRVJW",
+            "RVIQAiojCgdScGNUeXBlEgkKBVVOQVJZEAASDQoJU1RSRUFNSU5HEAFiBnBy",
+            "b3RvMw=="));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { global::Grpc.Testing.PayloadsReflection.Descriptor, global::Grpc.Testing.StatsReflection.Descriptor, },
           new pbr::GeneratedCodeInfo(new[] {typeof(global::Grpc.Testing.ClientType), typeof(global::Grpc.Testing.ServerType), typeof(global::Grpc.Testing.RpcType), }, new pbr::GeneratedCodeInfo[] {
@@ -76,13 +79,16 @@ namespace Grpc.Testing {
             new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ClosedLoopParams), global::Grpc.Testing.ClosedLoopParams.Parser, null, null, null, null),
             new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.LoadParams), global::Grpc.Testing.LoadParams.Parser, new[]{ "ClosedLoop", "Poisson", "Uniform", "Determ", "Pareto" }, new[]{ "Load" }, null, null),
             new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.SecurityParams), global::Grpc.Testing.SecurityParams.Parser, new[]{ "UseTestCa", "ServerHostOverride" }, null, null, null),
-            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ClientConfig), global::Grpc.Testing.ClientConfig.Parser, new[]{ "ServerTargets", "ClientType", "SecurityParams", "OutstandingRpcsPerChannel", "ClientChannels", "AsyncClientThreads", "RpcType", "LoadParams", "PayloadConfig", "HistogramParams" }, null, null, null),
+            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ClientConfig), global::Grpc.Testing.ClientConfig.Parser, new[]{ "ServerTargets", "ClientType", "SecurityParams", "OutstandingRpcsPerChannel", "ClientChannels", "AsyncClientThreads", "RpcType", "LoadParams", "PayloadConfig", "HistogramParams", "CoreList", "CoreLimit" }, null, null, null),
             new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ClientStatus), global::Grpc.Testing.ClientStatus.Parser, new[]{ "Stats" }, null, null, null),
             new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.Mark), global::Grpc.Testing.Mark.Parser, new[]{ "Reset" }, null, null, null),
             new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ClientArgs), global::Grpc.Testing.ClientArgs.Parser, new[]{ "Setup", "Mark" }, new[]{ "Argtype" }, null, null),
-            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ServerConfig), global::Grpc.Testing.ServerConfig.Parser, new[]{ "ServerType", "SecurityParams", "Host", "Port", "AsyncServerThreads", "CoreLimit", "PayloadConfig" }, null, null, null),
+            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ServerConfig), global::Grpc.Testing.ServerConfig.Parser, new[]{ "ServerType", "SecurityParams", "Port", "AsyncServerThreads", "CoreLimit", "PayloadConfig", "CoreList" }, null, null, null),
             new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ServerArgs), global::Grpc.Testing.ServerArgs.Parser, new[]{ "Setup", "Mark" }, new[]{ "Argtype" }, null, null),
-            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ServerStatus), global::Grpc.Testing.ServerStatus.Parser, new[]{ "Stats", "Port", "Cores" }, null, null, null)
+            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.ServerStatus), global::Grpc.Testing.ServerStatus.Parser, new[]{ "Stats", "Port", "Cores" }, null, null, null),
+            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.CoreRequest), global::Grpc.Testing.CoreRequest.Parser, null, null, null, null),
+            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.CoreResponse), global::Grpc.Testing.CoreResponse.Parser, new[]{ "Cores" }, null, null, null),
+            new pbr::GeneratedCodeInfo(typeof(global::Grpc.Testing.Void), global::Grpc.Testing.Void.Parser, null, null, null, null)
           }));
     }
     #endregion
@@ -97,6 +103,7 @@ namespace Grpc.Testing {
   public enum ServerType {
     SYNC_SERVER = 0,
     ASYNC_SERVER = 1,
+    ASYNC_GENERIC_SERVER = 2,
   }
 
   public enum RpcType {
@@ -1097,6 +1104,8 @@ namespace Grpc.Testing {
       LoadParams = other.loadParams_ != null ? other.LoadParams.Clone() : null;
       PayloadConfig = other.payloadConfig_ != null ? other.PayloadConfig.Clone() : null;
       HistogramParams = other.histogramParams_ != null ? other.HistogramParams.Clone() : null;
+      coreList_ = other.coreList_.Clone();
+      coreLimit_ = other.coreLimit_;
     }
 
     public ClientConfig Clone() {
@@ -1219,6 +1228,28 @@ namespace Grpc.Testing {
       }
     }
 
+    /// <summary>Field number for the "core_list" field.</summary>
+    public const int CoreListFieldNumber = 13;
+    private static readonly pb::FieldCodec<int> _repeated_coreList_codec
+        = pb::FieldCodec.ForInt32(106);
+    private readonly pbc::RepeatedField<int> coreList_ = new pbc::RepeatedField<int>();
+    /// <summary>
+    ///  Specify the cores we should run the client on, if desired
+    /// </summary>
+    public pbc::RepeatedField<int> CoreList {
+      get { return coreList_; }
+    }
+
+    /// <summary>Field number for the "core_limit" field.</summary>
+    public const int CoreLimitFieldNumber = 14;
+    private int coreLimit_;
+    public int CoreLimit {
+      get { return coreLimit_; }
+      set {
+        coreLimit_ = value;
+      }
+    }
+
     public override bool Equals(object other) {
       return Equals(other as ClientConfig);
     }
@@ -1240,6 +1271,8 @@ namespace Grpc.Testing {
       if (!object.Equals(LoadParams, other.LoadParams)) return false;
       if (!object.Equals(PayloadConfig, other.PayloadConfig)) return false;
       if (!object.Equals(HistogramParams, other.HistogramParams)) return false;
+      if(!coreList_.Equals(other.coreList_)) return false;
+      if (CoreLimit != other.CoreLimit) return false;
       return true;
     }
 
@@ -1255,6 +1288,8 @@ namespace Grpc.Testing {
       if (loadParams_ != null) hash ^= LoadParams.GetHashCode();
       if (payloadConfig_ != null) hash ^= PayloadConfig.GetHashCode();
       if (histogramParams_ != null) hash ^= HistogramParams.GetHashCode();
+      hash ^= coreList_.GetHashCode();
+      if (CoreLimit != 0) hash ^= CoreLimit.GetHashCode();
       return hash;
     }
 
@@ -1300,6 +1335,11 @@ namespace Grpc.Testing {
         output.WriteRawTag(98);
         output.WriteMessage(HistogramParams);
       }
+      coreList_.WriteTo(output, _repeated_coreList_codec);
+      if (CoreLimit != 0) {
+        output.WriteRawTag(112);
+        output.WriteInt32(CoreLimit);
+      }
     }
 
     public int CalculateSize() {
@@ -1332,6 +1372,10 @@ namespace Grpc.Testing {
       if (histogramParams_ != null) {
         size += 1 + pb::CodedOutputStream.ComputeMessageSize(HistogramParams);
       }
+      size += coreList_.CalculateSize(_repeated_coreList_codec);
+      if (CoreLimit != 0) {
+        size += 1 + pb::CodedOutputStream.ComputeInt32Size(CoreLimit);
+      }
       return size;
     }
 
@@ -1379,6 +1423,10 @@ namespace Grpc.Testing {
         }
         HistogramParams.MergeFrom(other.HistogramParams);
       }
+      coreList_.Add(other.coreList_);
+      if (other.CoreLimit != 0) {
+        CoreLimit = other.CoreLimit;
+      }
     }
 
     public void MergeFrom(pb::CodedInputStream input) {
@@ -1440,6 +1488,15 @@ namespace Grpc.Testing {
             input.ReadMessage(histogramParams_);
             break;
           }
+          case 106:
+          case 104: {
+            coreList_.AddEntriesFrom(input, _repeated_coreList_codec);
+            break;
+          }
+          case 112: {
+            CoreLimit = input.ReadInt32();
+            break;
+          }
         }
       }
     }
@@ -1855,11 +1912,11 @@ namespace Grpc.Testing {
     public ServerConfig(ServerConfig other) : this() {
       serverType_ = other.serverType_;
       SecurityParams = other.securityParams_ != null ? other.SecurityParams.Clone() : null;
-      host_ = other.host_;
       port_ = other.port_;
       asyncServerThreads_ = other.asyncServerThreads_;
       coreLimit_ = other.coreLimit_;
       PayloadConfig = other.payloadConfig_ != null ? other.PayloadConfig.Clone() : null;
+      coreList_ = other.coreList_.Clone();
     }
 
     public ServerConfig Clone() {
@@ -1886,19 +1943,6 @@ namespace Grpc.Testing {
       }
     }
 
-    /// <summary>Field number for the "host" field.</summary>
-    public const int HostFieldNumber = 3;
-    private string host_ = "";
-    /// <summary>
-    ///  Host on which to listen.
-    /// </summary>
-    public string Host {
-      get { return host_; }
-      set {
-        host_ = pb::Preconditions.CheckNotNull(value, "value");
-      }
-    }
-
     /// <summary>Field number for the "port" field.</summary>
     public const int PortFieldNumber = 4;
     private int port_;
@@ -1929,7 +1973,7 @@ namespace Grpc.Testing {
     public const int CoreLimitFieldNumber = 8;
     private int coreLimit_;
     /// <summary>
-    ///  restrict core usage, currently unused
+    ///  Specify the number of cores to limit server to, if desired
     /// </summary>
     public int CoreLimit {
       get { return coreLimit_; }
@@ -1941,6 +1985,9 @@ namespace Grpc.Testing {
     /// <summary>Field number for the "payload_config" field.</summary>
     public const int PayloadConfigFieldNumber = 9;
     private global::Grpc.Testing.PayloadConfig payloadConfig_;
+    /// <summary>
+    ///  payload config, used in generic server
+    /// </summary>
     public global::Grpc.Testing.PayloadConfig PayloadConfig {
       get { return payloadConfig_; }
       set {
@@ -1948,6 +1995,18 @@ namespace Grpc.Testing {
       }
     }
 
+    /// <summary>Field number for the "core_list" field.</summary>
+    public const int CoreListFieldNumber = 10;
+    private static readonly pb::FieldCodec<int> _repeated_coreList_codec
+        = pb::FieldCodec.ForInt32(82);
+    private readonly pbc::RepeatedField<int> coreList_ = new pbc::RepeatedField<int>();
+    /// <summary>
+    ///  Specify the cores we should run the server on, if desired
+    /// </summary>
+    public pbc::RepeatedField<int> CoreList {
+      get { return coreList_; }
+    }
+
     public override bool Equals(object other) {
       return Equals(other as ServerConfig);
     }
@@ -1961,11 +2020,11 @@ namespace Grpc.Testing {
       }
       if (ServerType != other.ServerType) return false;
       if (!object.Equals(SecurityParams, other.SecurityParams)) return false;
-      if (Host != other.Host) return false;
       if (Port != other.Port) return false;
       if (AsyncServerThreads != other.AsyncServerThreads) return false;
       if (CoreLimit != other.CoreLimit) return false;
       if (!object.Equals(PayloadConfig, other.PayloadConfig)) return false;
+      if(!coreList_.Equals(other.coreList_)) return false;
       return true;
     }
 
@@ -1973,11 +2032,11 @@ namespace Grpc.Testing {
       int hash = 1;
       if (ServerType != global::Grpc.Testing.ServerType.SYNC_SERVER) hash ^= ServerType.GetHashCode();
       if (securityParams_ != null) hash ^= SecurityParams.GetHashCode();
-      if (Host.Length != 0) hash ^= Host.GetHashCode();
       if (Port != 0) hash ^= Port.GetHashCode();
       if (AsyncServerThreads != 0) hash ^= AsyncServerThreads.GetHashCode();
       if (CoreLimit != 0) hash ^= CoreLimit.GetHashCode();
       if (payloadConfig_ != null) hash ^= PayloadConfig.GetHashCode();
+      hash ^= coreList_.GetHashCode();
       return hash;
     }
 
@@ -1994,10 +2053,6 @@ namespace Grpc.Testing {
         output.WriteRawTag(18);
         output.WriteMessage(SecurityParams);
       }
-      if (Host.Length != 0) {
-        output.WriteRawTag(26);
-        output.WriteString(Host);
-      }
       if (Port != 0) {
         output.WriteRawTag(32);
         output.WriteInt32(Port);
@@ -2014,6 +2069,7 @@ namespace Grpc.Testing {
         output.WriteRawTag(74);
         output.WriteMessage(PayloadConfig);
       }
+      coreList_.WriteTo(output, _repeated_coreList_codec);
     }
 
     public int CalculateSize() {
@@ -2024,9 +2080,6 @@ namespace Grpc.Testing {
       if (securityParams_ != null) {
         size += 1 + pb::CodedOutputStream.ComputeMessageSize(SecurityParams);
       }
-      if (Host.Length != 0) {
-        size += 1 + pb::CodedOutputStream.ComputeStringSize(Host);
-      }
       if (Port != 0) {
         size += 1 + pb::CodedOutputStream.ComputeInt32Size(Port);
       }
@@ -2039,6 +2092,7 @@ namespace Grpc.Testing {
       if (payloadConfig_ != null) {
         size += 1 + pb::CodedOutputStream.ComputeMessageSize(PayloadConfig);
       }
+      size += coreList_.CalculateSize(_repeated_coreList_codec);
       return size;
     }
 
@@ -2055,9 +2109,6 @@ namespace Grpc.Testing {
         }
         SecurityParams.MergeFrom(other.SecurityParams);
       }
-      if (other.Host.Length != 0) {
-        Host = other.Host;
-      }
       if (other.Port != 0) {
         Port = other.Port;
       }
@@ -2073,6 +2124,7 @@ namespace Grpc.Testing {
         }
         PayloadConfig.MergeFrom(other.PayloadConfig);
       }
+      coreList_.Add(other.coreList_);
     }
 
     public void MergeFrom(pb::CodedInputStream input) {
@@ -2093,10 +2145,6 @@ namespace Grpc.Testing {
             input.ReadMessage(securityParams_);
             break;
           }
-          case 26: {
-            Host = input.ReadString();
-            break;
-          }
           case 32: {
             Port = input.ReadInt32();
             break;
@@ -2116,6 +2164,11 @@ namespace Grpc.Testing {
             input.ReadMessage(payloadConfig_);
             break;
           }
+          case 82:
+          case 80: {
+            coreList_.AddEntriesFrom(input, _repeated_coreList_codec);
+            break;
+          }
         }
       }
     }
@@ -2347,7 +2400,7 @@ namespace Grpc.Testing {
     public const int CoresFieldNumber = 3;
     private int cores_;
     /// <summary>
-    ///  Number of cores on the server. See gpr_cpu_num_cores.
+    ///  Number of cores available to the server
     /// </summary>
     public int Cores {
       get { return cores_; }
@@ -2460,6 +2513,264 @@ namespace Grpc.Testing {
 
   }
 
+  [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+  public sealed partial class CoreRequest : pb::IMessage<CoreRequest> {
+    private static readonly pb::MessageParser<CoreRequest> _parser = new pb::MessageParser<CoreRequest>(() => new CoreRequest());
+    public static pb::MessageParser<CoreRequest> Parser { get { return _parser; } }
+
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Grpc.Testing.ControlReflection.Descriptor.MessageTypes[14]; }
+    }
+
+    pbr::MessageDescriptor pb::IMessage.Descriptor {
+      get { return Descriptor; }
+    }
+
+    public CoreRequest() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    public CoreRequest(CoreRequest other) : this() {
+    }
+
+    public CoreRequest Clone() {
+      return new CoreRequest(this);
+    }
+
+    public override bool Equals(object other) {
+      return Equals(other as CoreRequest);
+    }
+
+    public bool Equals(CoreRequest other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      return true;
+    }
+
+    public override int GetHashCode() {
+      int hash = 1;
+      return hash;
+    }
+
+    public override string ToString() {
+      return pb::JsonFormatter.ToDiagnosticString(this);
+    }
+
+    public void WriteTo(pb::CodedOutputStream output) {
+    }
+
+    public int CalculateSize() {
+      int size = 0;
+      return size;
+    }
+
+    public void MergeFrom(CoreRequest other) {
+      if (other == null) {
+        return;
+      }
+    }
+
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            input.SkipLastField();
+            break;
+        }
+      }
+    }
+
+  }
+
+  [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+  public sealed partial class CoreResponse : pb::IMessage<CoreResponse> {
+    private static readonly pb::MessageParser<CoreResponse> _parser = new pb::MessageParser<CoreResponse>(() => new CoreResponse());
+    public static pb::MessageParser<CoreResponse> Parser { get { return _parser; } }
+
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Grpc.Testing.ControlReflection.Descriptor.MessageTypes[15]; }
+    }
+
+    pbr::MessageDescriptor pb::IMessage.Descriptor {
+      get { return Descriptor; }
+    }
+
+    public CoreResponse() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    public CoreResponse(CoreResponse other) : this() {
+      cores_ = other.cores_;
+    }
+
+    public CoreResponse Clone() {
+      return new CoreResponse(this);
+    }
+
+    /// <summary>Field number for the "cores" field.</summary>
+    public const int CoresFieldNumber = 1;
+    private int cores_;
+    /// <summary>
+    ///  Number of cores available on the server
+    /// </summary>
+    public int Cores {
+      get { return cores_; }
+      set {
+        cores_ = value;
+      }
+    }
+
+    public override bool Equals(object other) {
+      return Equals(other as CoreResponse);
+    }
+
+    public bool Equals(CoreResponse other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      if (Cores != other.Cores) return false;
+      return true;
+    }
+
+    public override int GetHashCode() {
+      int hash = 1;
+      if (Cores != 0) hash ^= Cores.GetHashCode();
+      return hash;
+    }
+
+    public override string ToString() {
+      return pb::JsonFormatter.ToDiagnosticString(this);
+    }
+
+    public void WriteTo(pb::CodedOutputStream output) {
+      if (Cores != 0) {
+        output.WriteRawTag(8);
+        output.WriteInt32(Cores);
+      }
+    }
+
+    public int CalculateSize() {
+      int size = 0;
+      if (Cores != 0) {
+        size += 1 + pb::CodedOutputStream.ComputeInt32Size(Cores);
+      }
+      return size;
+    }
+
+    public void MergeFrom(CoreResponse other) {
+      if (other == null) {
+        return;
+      }
+      if (other.Cores != 0) {
+        Cores = other.Cores;
+      }
+    }
+
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            input.SkipLastField();
+            break;
+          case 8: {
+            Cores = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    }
+
+  }
+
+  [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+  public sealed partial class Void : pb::IMessage<Void> {
+    private static readonly pb::MessageParser<Void> _parser = new pb::MessageParser<Void>(() => new Void());
+    public static pb::MessageParser<Void> Parser { get { return _parser; } }
+
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Grpc.Testing.ControlReflection.Descriptor.MessageTypes[16]; }
+    }
+
+    pbr::MessageDescriptor pb::IMessage.Descriptor {
+      get { return Descriptor; }
+    }
+
+    public Void() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    public Void(Void other) : this() {
+    }
+
+    public Void Clone() {
+      return new Void(this);
+    }
+
+    public override bool Equals(object other) {
+      return Equals(other as Void);
+    }
+
+    public bool Equals(Void other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      return true;
+    }
+
+    public override int GetHashCode() {
+      int hash = 1;
+      return hash;
+    }
+
+    public override string ToString() {
+      return pb::JsonFormatter.ToDiagnosticString(this);
+    }
+
+    public void WriteTo(pb::CodedOutputStream output) {
+    }
+
+    public int CalculateSize() {
+      int size = 0;
+      return size;
+    }
+
+    public void MergeFrom(Void other) {
+      if (other == null) {
+        return;
+      }
+    }
+
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            input.SkipLastField();
+            break;
+        }
+      }
+    }
+
+  }
+
   #endregion
 
 }
diff --git a/src/csharp/Grpc.IntegrationTesting/QpsWorker.cs b/src/csharp/Grpc.IntegrationTesting/QpsWorker.cs
index 686b484345..e407792c4b 100644
--- a/src/csharp/Grpc.IntegrationTesting/QpsWorker.cs
+++ b/src/csharp/Grpc.IntegrationTesting/QpsWorker.cs
@@ -1,6 +1,6 @@
 #region Copyright notice and license
 
-// Copyright 2015, Google Inc.
+// Copyright 2015-2016, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -85,24 +85,27 @@ namespace Grpc.IntegrationTesting
             }
 
             var workerServer = new QpsWorker(options);
-            workerServer.Run();
+            workerServer.RunAsync().Wait();
         }
 
-        private void Run()
+        private async Task RunAsync()
         {
             string host = "0.0.0.0";
             int port = options.DriverPort;
 
+            var tcs = new TaskCompletionSource<object>();
+            var workerServiceImpl = new WorkerServiceImpl(() => { Task.Run(() => tcs.SetResult(null)); });
+                
             var server = new Server
             {
-                Services = { WorkerService.BindService(new WorkerServiceImpl()) },
+                Services = { WorkerService.BindService(workerServiceImpl) },
                 Ports = { new ServerPort(host, options.DriverPort, ServerCredentials.Insecure )}
             };
             int boundPort = server.Ports.Single().BoundPort;
             Console.WriteLine("Running qps worker server on " + string.Format("{0}:{1}", host, boundPort));
             server.Start();
-
-            server.ShutdownTask.Wait();
+            await tcs.Task;
+            await server.ShutdownAsync();
         }
     }
 }
diff --git a/src/csharp/Grpc.IntegrationTesting/RunnerClientServerTest.cs b/src/csharp/Grpc.IntegrationTesting/RunnerClientServerTest.cs
index 3dd91b7948..06d5ee93d8 100644
--- a/src/csharp/Grpc.IntegrationTesting/RunnerClientServerTest.cs
+++ b/src/csharp/Grpc.IntegrationTesting/RunnerClientServerTest.cs
@@ -1,6 +1,6 @@
 #region Copyright notice and license
 
-// Copyright 2015, Google Inc.
+// Copyright 2015-2016, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -48,7 +48,6 @@ namespace Grpc.IntegrationTesting
     /// </summary>
     public class RunnerClientServerTest
     {
-        const string Host = "localhost";
         IServerRunner serverRunner;
 
         [TestFixtureSetUp]
@@ -57,7 +56,6 @@ namespace Grpc.IntegrationTesting
             var serverConfig = new ServerConfig
             {
                 ServerType = ServerType.ASYNC_SERVER,
-                Host = Host,
                 PayloadConfig = new PayloadConfig
                 {
                     SimpleParams = new SimpleProtoParams
@@ -83,7 +81,7 @@ namespace Grpc.IntegrationTesting
         {
             var config = new ClientConfig
             {
-                ServerTargets = { string.Format("{0}:{1}", Host, serverRunner.BoundPort) },
+                ServerTargets = { string.Format("{0}:{1}", "localhost", serverRunner.BoundPort) },
                 RpcType = RpcType.UNARY,
                 LoadParams = new LoadParams { ClosedLoop = new ClosedLoopParams() },
                 PayloadConfig = new PayloadConfig
diff --git a/src/csharp/Grpc.IntegrationTesting/ServerRunners.cs b/src/csharp/Grpc.IntegrationTesting/ServerRunners.cs
index 9b09b9bdd3..4a73645e6c 100644
--- a/src/csharp/Grpc.IntegrationTesting/ServerRunners.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ServerRunners.cs
@@ -65,7 +65,7 @@ namespace Grpc.IntegrationTesting
             var server = new Server
             {
                 Services = { BenchmarkService.BindService(new BenchmarkServiceImpl(responseSize)) },
-                Ports = { new ServerPort(config.Host, config.Port, credentials) }
+                Ports = { new ServerPort("[::]", config.Port, credentials) }
             };
 
             server.Start();
diff --git a/src/csharp/Grpc.IntegrationTesting/Services.cs b/src/csharp/Grpc.IntegrationTesting/Services.cs
index 04a092ccd7..a8475c1817 100644
--- a/src/csharp/Grpc.IntegrationTesting/Services.cs
+++ b/src/csharp/Grpc.IntegrationTesting/Services.cs
@@ -29,11 +29,14 @@ namespace Grpc.Testing {
             "QmVuY2htYXJrU2VydmljZRJGCglVbmFyeUNhbGwSGy5ncnBjLnRlc3Rpbmcu",
             "U2ltcGxlUmVxdWVzdBocLmdycGMudGVzdGluZy5TaW1wbGVSZXNwb25zZRJO",
             "Cg1TdHJlYW1pbmdDYWxsEhsuZ3JwYy50ZXN0aW5nLlNpbXBsZVJlcXVlc3Qa",
-            "HC5ncnBjLnRlc3RpbmcuU2ltcGxlUmVzcG9uc2UoATABMp0BCg1Xb3JrZXJT",
+            "HC5ncnBjLnRlc3RpbmcuU2ltcGxlUmVzcG9uc2UoATABMpcCCg1Xb3JrZXJT",
             "ZXJ2aWNlEkUKCVJ1blNlcnZlchIYLmdycGMudGVzdGluZy5TZXJ2ZXJBcmdz",
             "GhouZ3JwYy50ZXN0aW5nLlNlcnZlclN0YXR1cygBMAESRQoJUnVuQ2xpZW50",
             "EhguZ3JwYy50ZXN0aW5nLkNsaWVudEFyZ3MaGi5ncnBjLnRlc3RpbmcuQ2xp",
-            "ZW50U3RhdHVzKAEwAWIGcHJvdG8z"));
+            "ZW50U3RhdHVzKAEwARJCCglDb3JlQ291bnQSGS5ncnBjLnRlc3RpbmcuQ29y",
+            "ZVJlcXVlc3QaGi5ncnBjLnRlc3RpbmcuQ29yZVJlc3BvbnNlEjQKClF1aXRX",
+            "b3JrZXISEi5ncnBjLnRlc3RpbmcuVm9pZBoSLmdycGMudGVzdGluZy5Wb2lk",
+            "YgZwcm90bzM="));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { global::Grpc.Testing.MessagesReflection.Descriptor, global::Grpc.Testing.ControlReflection.Descriptor, },
           new pbr::GeneratedCodeInfo(null, null));
diff --git a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
index dd30afb427..996439afbf 100644
--- a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
@@ -114,6 +114,9 @@ namespace Grpc.Testing {
     static readonly Marshaller<global::Grpc.Testing.ServerStatus> __Marshaller_ServerStatus = Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Grpc.Testing.ServerStatus.Parser.ParseFrom);
     static readonly Marshaller<global::Grpc.Testing.ClientArgs> __Marshaller_ClientArgs = Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Grpc.Testing.ClientArgs.Parser.ParseFrom);
     static readonly Marshaller<global::Grpc.Testing.ClientStatus> __Marshaller_ClientStatus = Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Grpc.Testing.ClientStatus.Parser.ParseFrom);
+    static readonly Marshaller<global::Grpc.Testing.CoreRequest> __Marshaller_CoreRequest = Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Grpc.Testing.CoreRequest.Parser.ParseFrom);
+    static readonly Marshaller<global::Grpc.Testing.CoreResponse> __Marshaller_CoreResponse = Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Grpc.Testing.CoreResponse.Parser.ParseFrom);
+    static readonly Marshaller<global::Grpc.Testing.Void> __Marshaller_Void = Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Grpc.Testing.Void.Parser.ParseFrom);
 
     static readonly Method<global::Grpc.Testing.ServerArgs, global::Grpc.Testing.ServerStatus> __Method_RunServer = new Method<global::Grpc.Testing.ServerArgs, global::Grpc.Testing.ServerStatus>(
         MethodType.DuplexStreaming,
@@ -129,6 +132,20 @@ namespace Grpc.Testing {
         __Marshaller_ClientArgs,
         __Marshaller_ClientStatus);
 
+    static readonly Method<global::Grpc.Testing.CoreRequest, global::Grpc.Testing.CoreResponse> __Method_CoreCount = new Method<global::Grpc.Testing.CoreRequest, global::Grpc.Testing.CoreResponse>(
+        MethodType.Unary,
+        __ServiceName,
+        "CoreCount",
+        __Marshaller_CoreRequest,
+        __Marshaller_CoreResponse);
+
+    static readonly Method<global::Grpc.Testing.Void, global::Grpc.Testing.Void> __Method_QuitWorker = new Method<global::Grpc.Testing.Void, global::Grpc.Testing.Void>(
+        MethodType.Unary,
+        __ServiceName,
+        "QuitWorker",
+        __Marshaller_Void,
+        __Marshaller_Void);
+
     // service descriptor
     public static global::Google.Protobuf.Reflection.ServiceDescriptor Descriptor
     {
@@ -142,6 +159,14 @@ namespace Grpc.Testing {
       AsyncDuplexStreamingCall<global::Grpc.Testing.ServerArgs, global::Grpc.Testing.ServerStatus> RunServer(CallOptions options);
       AsyncDuplexStreamingCall<global::Grpc.Testing.ClientArgs, global::Grpc.Testing.ClientStatus> RunClient(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken));
       AsyncDuplexStreamingCall<global::Grpc.Testing.ClientArgs, global::Grpc.Testing.ClientStatus> RunClient(CallOptions options);
+      global::Grpc.Testing.CoreResponse CoreCount(global::Grpc.Testing.CoreRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken));
+      global::Grpc.Testing.CoreResponse CoreCount(global::Grpc.Testing.CoreRequest request, CallOptions options);
+      AsyncUnaryCall<global::Grpc.Testing.CoreResponse> CoreCountAsync(global::Grpc.Testing.CoreRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken));
+      AsyncUnaryCall<global::Grpc.Testing.CoreResponse> CoreCountAsync(global::Grpc.Testing.CoreRequest request, CallOptions options);
+      global::Grpc.Testing.Void QuitWorker(global::Grpc.Testing.Void request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken));
+      global::Grpc.Testing.Void QuitWorker(global::Grpc.Testing.Void request, CallOptions options);
+      AsyncUnaryCall<global::Grpc.Testing.Void> QuitWorkerAsync(global::Grpc.Testing.Void request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken));
+      AsyncUnaryCall<global::Grpc.Testing.Void> QuitWorkerAsync(global::Grpc.Testing.Void request, CallOptions options);
     }
 
     // server-side interface
@@ -149,6 +174,8 @@ namespace Grpc.Testing {
     {
       Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context);
       Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context);
+      Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context);
+      Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context);
     }
 
     // client stub
@@ -177,6 +204,46 @@ namespace Grpc.Testing {
         var call = CreateCall(__Method_RunClient, options);
         return Calls.AsyncDuplexStreamingCall(call);
       }
+      public global::Grpc.Testing.CoreResponse CoreCount(global::Grpc.Testing.CoreRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
+      {
+        var call = CreateCall(__Method_CoreCount, new CallOptions(headers, deadline, cancellationToken));
+        return Calls.BlockingUnaryCall(call, request);
+      }
+      public global::Grpc.Testing.CoreResponse CoreCount(global::Grpc.Testing.CoreRequest request, CallOptions options)
+      {
+        var call = CreateCall(__Method_CoreCount, options);
+        return Calls.BlockingUnaryCall(call, request);
+      }
+      public AsyncUnaryCall<global::Grpc.Testing.CoreResponse> CoreCountAsync(global::Grpc.Testing.CoreRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
+      {
+        var call = CreateCall(__Method_CoreCount, new CallOptions(headers, deadline, cancellationToken));
+        return Calls.AsyncUnaryCall(call, request);
+      }
+      public AsyncUnaryCall<global::Grpc.Testing.CoreResponse> CoreCountAsync(global::Grpc.Testing.CoreRequest request, CallOptions options)
+      {
+        var call = CreateCall(__Method_CoreCount, options);
+        return Calls.AsyncUnaryCall(call, request);
+      }
+      public global::Grpc.Testing.Void QuitWorker(global::Grpc.Testing.Void request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
+      {
+        var call = CreateCall(__Method_QuitWorker, new CallOptions(headers, deadline, cancellationToken));
+        return Calls.BlockingUnaryCall(call, request);
+      }
+      public global::Grpc.Testing.Void QuitWorker(global::Grpc.Testing.Void request, CallOptions options)
+      {
+        var call = CreateCall(__Method_QuitWorker, options);
+        return Calls.BlockingUnaryCall(call, request);
+      }
+      public AsyncUnaryCall<global::Grpc.Testing.Void> QuitWorkerAsync(global::Grpc.Testing.Void request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
+      {
+        var call = CreateCall(__Method_QuitWorker, new CallOptions(headers, deadline, cancellationToken));
+        return Calls.AsyncUnaryCall(call, request);
+      }
+      public AsyncUnaryCall<global::Grpc.Testing.Void> QuitWorkerAsync(global::Grpc.Testing.Void request, CallOptions options)
+      {
+        var call = CreateCall(__Method_QuitWorker, options);
+        return Calls.AsyncUnaryCall(call, request);
+      }
     }
 
     // creates service definition that can be registered with a server
@@ -184,7 +251,9 @@ namespace Grpc.Testing {
     {
       return ServerServiceDefinition.CreateBuilder(__ServiceName)
           .AddMethod(__Method_RunServer, serviceImpl.RunServer)
-          .AddMethod(__Method_RunClient, serviceImpl.RunClient).Build();
+          .AddMethod(__Method_RunClient, serviceImpl.RunClient)
+          .AddMethod(__Method_CoreCount, serviceImpl.CoreCount)
+          .AddMethod(__Method_QuitWorker, serviceImpl.QuitWorker).Build();
     }
 
     // creates a new client
diff --git a/src/csharp/Grpc.IntegrationTesting/WorkerServiceImpl.cs b/src/csharp/Grpc.IntegrationTesting/WorkerServiceImpl.cs
index 59ecebf5a2..cab299a137 100644
--- a/src/csharp/Grpc.IntegrationTesting/WorkerServiceImpl.cs
+++ b/src/csharp/Grpc.IntegrationTesting/WorkerServiceImpl.cs
@@ -47,6 +47,13 @@ namespace Grpc.Testing
     /// </summary>
     public class WorkerServiceImpl : WorkerService.IWorkerService
     {
+        readonly Action stopRequestHandler;
+
+        public WorkerServiceImpl(Action stopRequestHandler)
+        {
+            this.stopRequestHandler = GrpcPreconditions.CheckNotNull(stopRequestHandler);
+        }
+        
         public async Task RunServer(IAsyncStreamReader<ServerArgs> requestStream, IServerStreamWriter<ServerStatus> responseStream, ServerCallContext context)
         {
             GrpcPreconditions.CheckState(await requestStream.MoveNext());
@@ -92,5 +99,16 @@ namespace Grpc.Testing
             }
             await runner.StopAsync();
         }
+
+        public Task<CoreResponse> CoreCount(CoreRequest request, ServerCallContext context)
+        {
+            return Task.FromResult(new CoreResponse { Cores = Environment.ProcessorCount });
+        }
+
+        public Task<Void> QuitWorker(Void request, ServerCallContext context)
+        {
+            stopRequestHandler();
+            return Task.FromResult(new Void());
+        }
     }
 }
diff --git a/src/proto/grpc/lb/v0/load_balancer.options b/src/proto/grpc/lb/v0/load_balancer.options
new file mode 100644
index 0000000000..6d4528f838
--- /dev/null
+++ b/src/proto/grpc/lb/v0/load_balancer.options
@@ -0,0 +1,6 @@
+grpc.lb.v0.InitialLoadBalanceRequest.name max_size:128
+grpc.lb.v0.InitialLoadBalanceResponse.client_config max_size:64
+grpc.lb.v0.InitialLoadBalanceResponse.load_balancer_delegate max_size:64
+grpc.lb.v0.Server.ip_address max_size:46
+grpc.lb.v0.Server.load_balance_token max_size:64
+load_balancer.proto no_unions:true
diff --git a/src/proto/grpc/lb/v0/load_balancer.proto b/src/proto/grpc/lb/v0/load_balancer.proto
new file mode 100644
index 0000000000..e88a4f8c4a
--- /dev/null
+++ b/src/proto/grpc/lb/v0/load_balancer.proto
@@ -0,0 +1,144 @@
+// Copyright 2016, 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.
+
+syntax = "proto3";
+
+package grpc.lb.v0;
+
+message Duration {
+
+  // Signed seconds of the span of time. Must be from -315,576,000,000
+  // to +315,576,000,000 inclusive.
+  int64 seconds = 1;
+
+  // Signed fractions of a second at nanosecond resolution of the span
+  // of time. Durations less than one second are represented with a 0
+  // `seconds` field and a positive or negative `nanos` field. For durations
+  // of one second or more, a non-zero value for the `nanos` field must be
+  // of the same sign as the `seconds` field. Must be from -999,999,999
+  // to +999,999,999 inclusive.
+  int32 nanos = 2;
+}
+
+service LoadBalancer {
+  // Bidirectional rpc to get a list of servers.
+  rpc BalanceLoad(stream LoadBalanceRequest)
+      returns (stream LoadBalanceResponse);
+}
+
+message LoadBalanceRequest {
+  oneof load_balance_request_type {
+    // This message should be sent on the first request to the load balancer.
+    InitialLoadBalanceRequest initial_request = 1;
+
+    // The client stats should be periodically reported to the load balancer
+    // based on the duration defined in the InitialLoadBalanceResponse.
+    ClientStats client_stats = 2;
+  }
+}
+
+message InitialLoadBalanceRequest {
+  // Name of load balanced service (IE, service.grpc.gslb.google.com)
+  string name = 1;
+}
+
+// Contains client level statistics that are useful to load balancing. Each
+// count should be reset to zero after reporting the stats.
+message ClientStats {
+  // The total number of requests sent by the client since the last report.
+  int64 total_requests = 1;
+
+  // The number of client rpc errors since the last report.
+  int64 client_rpc_errors = 2;
+
+  // The number of dropped requests since the last report.
+  int64 dropped_requests = 3;
+}
+
+message LoadBalanceResponse {
+  oneof load_balance_response_type {
+    // This message should be sent on the first response to the client.
+    InitialLoadBalanceResponse initial_response = 1;
+
+    // Contains the list of servers selected by the load balancer. The client
+    // should send requests to these servers in the specified order.
+    ServerList server_list = 2;
+  }
+}
+
+message InitialLoadBalanceResponse {
+  oneof initial_response_type {
+    // Contains gRPC config options like RPC deadline or flow control.
+    // TODO(yetianx): Change to ClientConfig after it is defined.
+    string client_config = 1;
+
+    // This is an application layer redirect that indicates the client should
+    // use the specified server for load balancing. When this field is set in
+    // the response, the client should open a separate connection to the
+    // load_balancer_delegate and call the BalanceLoad method.
+    string load_balancer_delegate = 2;
+  }
+
+  // This interval defines how often the client should send the client stats
+  // to the load balancer. Stats should only be reported when the duration is
+  // positive.
+  Duration client_stats_report_interval = 3;
+}
+
+message ServerList {
+  // Contains a list of servers selected by the load balancer. The list will
+  // be updated when server resolutions change or as needed to balance load
+  // across more servers. The client should consume the server list in order
+  // unless instructed otherwise via the client_config.
+  repeated Server servers = 1;
+
+  // Indicates the amount of time that the client should consider this server
+  // list as valid. It may be considered stale after waiting this interval of
+  // time after receiving the list. If the interval is not positive, the
+  // client can assume the list is valid until the next list is received.
+  Duration expiration_interval = 3;
+}
+
+message Server {
+  // A resolved address and port for the server. The IP address string may
+  // either be an IPv4 or IPv6 address.
+  string ip_address = 1;
+  int32 port = 2;
+
+  // An opaque token that is passed from the client to the server in metadata.
+  // The server may expect this token to indicate that the request from the
+  // client was load balanced.
+  // TODO(yetianx): Not used right now, and will be used after implementing
+  // load report.
+  bytes load_balance_token = 3;
+
+  // Indicates whether this particular request should be dropped by the client
+  // when this server is chosen from the list.
+  bool drop_request = 4;
+}
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index a002a5a0a8..c020fda284 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -88,6 +88,7 @@ CORE_SOURCE_FILES = [
   'src/core/client_config/connector.c',
   'src/core/client_config/default_initial_connect_string.c',
   'src/core/client_config/initial_connect_string.c',
+  'src/core/client_config/lb_policies/load_balancer_api.c',
   'src/core/client_config/lb_policies/pick_first.c',
   'src/core/client_config/lb_policies/round_robin.c',
   'src/core/client_config/lb_policy.c',
@@ -152,6 +153,7 @@ CORE_SOURCE_FILES = [
   'src/core/json/json_reader.c',
   'src/core/json/json_string.c',
   'src/core/json/json_writer.c',
+  'src/core/proto/grpc/lb/v0/load_balancer.pb.c',
   'src/core/surface/alarm.c',
   'src/core/surface/api_trace.c',
   'src/core/surface/byte_buffer.c',
@@ -228,6 +230,9 @@ CORE_SOURCE_FILES = [
   'src/core/census/operation.c',
   'src/core/census/placeholders.c',
   'src/core/census/tracing.c',
+  'third_party/nanopb/pb_common.c',
+  'third_party/nanopb/pb_decode.c',
+  'third_party/nanopb/pb_encode.c',
   'src/boringssl/err_data.c',
   'third_party/boringssl/crypto/aes/aes.c',
   'third_party/boringssl/crypto/aes/mode_wrappers.c',