Introducing iomgr.

Move eventmanager and platform dependent endpoint functionality into a single
library called 'iomgr'.

This is primarily to prepare for a Windows port - where posix socket semantics
lead to poor quality code.

Mostly this is a code movement CL, with some small changes to help prepare the
way for porting:

- em style fd objects can only be held internally in iomgr, and own their memory
- added grpc_iomgr_create_endpoint_pair() to accomodate the common pattern of
creating a tcp endpoint from the output of socketpair - this will help keep
our tests portable
- separated em alarm interface into a separate file, as this part of event
manager is needed higher up the stack
- made the eventmanager bits a true singleton, simplifying API's across the
stack as there's no longer a reason to carry a pointer there.

Initial design document is here:
https://docs.google.com/document/d/1VmafcHvvrP5kwtQkz84R5yXF7u7fW-9Pn0bkSUQHDt8/edit?disco=AAAAARNByxg
	Change on 2014/12/09 by ctiller <ctiller@google.com>
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=81716456
diff --git a/src/core/iomgr/sockaddr_utils.c b/src/core/iomgr/sockaddr_utils.c
new file mode 100644
index 0000000..f709d35
--- /dev/null
+++ b/src/core/iomgr/sockaddr_utils.c
@@ -0,0 +1,155 @@
+/*
+ *
+ * Copyright 2014, 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/iomgr/sockaddr_utils.h"
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <string.h>
+
+#include <grpc/support/host_port.h>
+#include <grpc/support/string.h>
+#include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
+
+static const gpr_uint8 kV4MappedPrefix[] = {0, 0, 0, 0, 0,    0,
+                                            0, 0, 0, 0, 0xff, 0xff};
+
+int grpc_sockaddr_is_v4mapped(const struct sockaddr *addr,
+                              struct sockaddr_in *addr4_out) {
+  GPR_ASSERT(addr != (struct sockaddr *)addr4_out);
+  if (addr->sa_family == AF_INET6) {
+    const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
+    if (memcmp(addr6->sin6_addr.s6_addr, kV4MappedPrefix,
+               sizeof(kV4MappedPrefix)) == 0) {
+      if (addr4_out != NULL) {
+        /* Normalize ::ffff:0.0.0.0/96 to IPv4. */
+        memset(addr4_out, 0, sizeof(*addr4_out));
+        addr4_out->sin_family = AF_INET;
+        /* s6_addr32 would be nice, but it's non-standard. */
+        memcpy(&addr4_out->sin_addr, &addr6->sin6_addr.s6_addr[12], 4);
+        addr4_out->sin_port = addr6->sin6_port;
+      }
+      return 1;
+    }
+  }
+  return 0;
+}
+
+int grpc_sockaddr_to_v4mapped(const struct sockaddr *addr,
+                              struct sockaddr_in6 *addr6_out) {
+  GPR_ASSERT(addr != (struct sockaddr *)addr6_out);
+  if (addr->sa_family == AF_INET) {
+    const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
+    memset(addr6_out, 0, sizeof(*addr6_out));
+    addr6_out->sin6_family = AF_INET6;
+    memcpy(&addr6_out->sin6_addr.s6_addr[0], kV4MappedPrefix, 12);
+    memcpy(&addr6_out->sin6_addr.s6_addr[12], &addr4->sin_addr, 4);
+    addr6_out->sin6_port = addr4->sin_port;
+    return 1;
+  }
+  return 0;
+}
+
+int grpc_sockaddr_is_wildcard(const struct sockaddr *addr, int *port_out) {
+  struct sockaddr_in addr4_normalized;
+  if (grpc_sockaddr_is_v4mapped(addr, &addr4_normalized)) {
+    addr = (struct sockaddr *)&addr4_normalized;
+  }
+  if (addr->sa_family == AF_INET) {
+    /* Check for 0.0.0.0 */
+    const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
+    if (addr4->sin_addr.s_addr != 0) {
+      return 0;
+    }
+    *port_out = ntohs(addr4->sin_port);
+    return 1;
+  } else if (addr->sa_family == AF_INET6) {
+    /* Check for :: */
+    const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
+    int i;
+    for (i = 0; i < 16; i++) {
+      if (addr6->sin6_addr.s6_addr[i] != 0) {
+        return 0;
+      }
+    }
+    *port_out = ntohs(addr6->sin6_port);
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+void grpc_sockaddr_make_wildcards(int port, struct sockaddr_in *wild4_out,
+                                  struct sockaddr_in6 *wild6_out) {
+  memset(wild4_out, 0, sizeof(*wild4_out));
+  wild4_out->sin_family = AF_INET;
+  wild4_out->sin_port = htons(port);
+
+  memset(wild6_out, 0, sizeof(*wild6_out));
+  wild6_out->sin6_family = AF_INET6;
+  wild6_out->sin6_port = htons(port);
+}
+
+int grpc_sockaddr_to_string(char **out, const struct sockaddr *addr,
+                            int normalize) {
+  const int save_errno = errno;
+  struct sockaddr_in addr_normalized;
+  char ntop_buf[INET6_ADDRSTRLEN];
+  const void *ip = NULL;
+  int port;
+  int ret;
+
+  *out = NULL;
+  if (normalize && grpc_sockaddr_is_v4mapped(addr, &addr_normalized)) {
+    addr = (const struct sockaddr *)&addr_normalized;
+  }
+  if (addr->sa_family == AF_INET) {
+    const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
+    ip = &addr4->sin_addr;
+    port = ntohs(addr4->sin_port);
+  } else if (addr->sa_family == AF_INET6) {
+    const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
+    ip = &addr6->sin6_addr;
+    port = ntohs(addr6->sin6_port);
+  }
+  if (ip != NULL &&
+      inet_ntop(addr->sa_family, ip, ntop_buf, sizeof(ntop_buf)) != NULL) {
+    ret = gpr_join_host_port(out, ntop_buf, port);
+  } else {
+    ret = gpr_asprintf(out, "(sockaddr family=%d)", addr->sa_family);
+  }
+  /* This is probably redundant, but we wouldn't want to log the wrong error. */
+  errno = save_errno;
+  return ret;
+}