Network status tracking

Recreated the old PR (https://github.com/grpc/grpc/pull/6283) in a new
repo since the old repo was destroyed. Removed changes to tcp_posix.c
and tpc_windows.c, instead depending on the idempotent endpoint shutdown code
from https://github.com/grpc/grpc/pull/6911.

2 files changed, 122 insertions, 0 deletions

diff --git a/src/core/lib/iomgr/network_status_tracker.c b/src/core/lib/iomgr/network_status_tracker.c
new file mode 100644
index 0000000000..6e432368cf
--- /dev/null
+++ b/src/core/lib/iomgr/network_status_tracker.c
@@ -0,0 +1,82 @@
+/*
+ *
+ * Copyright 2015, 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/lib/iomgr/endpoint.h"
+#include <grpc/support/alloc.h>
+
+typedef struct endpoint_ll_node {
+  grpc_endpoint *ep;
+  struct endpoint_ll_node *next;
+} endpoint_ll_node;
+
+static endpoint_ll_node *head = NULL;
+
+// TODO(makarandd): Install callback with OS to monitor network status.
+void grpc_initialize_network_status_monitor() {
+}
+
+void grpc_destroy_network_status_monitor() {
+  for (endpoint_ll_node *curr = head; curr != NULL; ) {
+    endpoint_ll_node *next = curr->next;
+    gpr_free(curr);
+    curr = next;
+  }
+}
+
+void grpc_network_status_register_endpoint(grpc_endpoint *ep) {
+  if (head == NULL) {
+    head = (endpoint_ll_node *)gpr_malloc(sizeof(endpoint_ll_node));
+    head->ep = ep;
+    head->next = NULL;
+  } else {
+    endpoint_ll_node *prev_head = head;
+    head = (endpoint_ll_node *)gpr_malloc(sizeof(endpoint_ll_node));
+    head->ep = ep;
+    head->next = prev_head;
+  }
+}
+
+// Walk the linked-list from head and execute shutdown. It is possible that
+// other threads might be in the process of shutdown as well, but that has
+// no side effect.
+void grpc_network_status_shutdown_all_endpoints() {
+  if (head == NULL) {
+    return;
+  }
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+
+  for (endpoint_ll_node *curr = head; curr != NULL; curr = curr->next) {
+    curr->ep->vtable->shutdown(&exec_ctx, curr->ep);
+  }
+  grpc_exec_ctx_finish(&exec_ctx);
+}
diff --git a/src/core/lib/iomgr/network_status_tracker.h b/src/core/lib/iomgr/network_status_tracker.h
new file mode 100644
index 0000000000..4154151927
--- /dev/null
+++ b/src/core/lib/iomgr/network_status_tracker.h
@@ -0,0 +1,40 @@
+/*
+ *
+ * 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_CORE_LIB_IOMGR_NETWORK_STATUS_TRACKER_H
+#define GRPC_CORE_LIB_IOMGR_NETWORK_STATUS_TRACKER_H
+#include "src/core/lib/iomgr/endpoint.h"
+
+void grpc_network_status_register_endpoint(grpc_endpoint *ep);
+void grpc_network_status_shutdown_all_endpoints();
+#endif /* GRPC_CORE_LIB_IOMGR_NETWORK_STATUS_TRACKER_H */