Initial checkin of gRPC to third_party/

third_party/grpc/src/core/iomgr/socket_utils_posix.h

Index: third_party/grpc/src/core/iomgr/socket_utils_posix.h
diff --git a/third_party/grpc/src/core/iomgr/socket_utils_posix.h b/third_party/grpc/src/core/iomgr/socket_utils_posix.h
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+/*
+ *
+ * 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.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_IOMGR_SOCKET_UTILS_POSIX_H
+#define GRPC_INTERNAL_CORE_IOMGR_SOCKET_UTILS_POSIX_H
+
+#include <unistd.h>
+#include <sys/socket.h>
+
+/* a wrapper for accept or accept4 */
+int grpc_accept4(int sockfd, struct sockaddr *addr, socklen_t *addrlen,
+                 int nonblock, int cloexec);
+
+/* set a socket to non blocking mode */
+int grpc_set_socket_nonblocking(int fd, int non_blocking);
+
+/* set a socket to close on exec */
+int grpc_set_socket_cloexec(int fd, int close_on_exec);
+
+/* set a socket to reuse old addresses */
+int grpc_set_socket_reuse_addr(int fd, int reuse);
+
+/* disable nagle */
+int grpc_set_socket_low_latency(int fd, int low_latency);
+
+/* Returns true if this system can create AF_INET6 sockets bound to ::1.
+   The value is probed once, and cached for the life of the process.
+
+   This is more restrictive than checking for socket(AF_INET6) to succeed,
+   because Linux with "net.ipv6.conf.all.disable_ipv6 = 1" is able to create
+   and bind IPv6 sockets, but cannot connect to a getsockname() of [::]:port
+   without a valid loopback interface.  Rather than expose this half-broken
+   state to library users, we turn off IPv6 sockets. */
+int grpc_ipv6_loopback_available(void);
+
+/* Tries to set SO_NOSIGPIPE if available on this platform.
+   Returns 1 on success, 0 on failure.
+   If SO_NO_SIGPIPE is not available, returns 1. */
+int grpc_set_socket_no_sigpipe_if_possible(int fd);
+
+/* An enum to keep track of IPv4/IPv6 socket modes.
+
+   Currently, this information is only used when a socket is first created, but
+   in the future we may wish to store it alongside the fd.  This would let calls
+   like sendto() know which family to use without asking the kernel first. */
+typedef enum grpc_dualstack_mode {
+  /* Uninitialized, or a non-IP socket. */
+  GRPC_DSMODE_NONE,
+  /* AF_INET only. */
+  GRPC_DSMODE_IPV4,
+  /* AF_INET6 only, because IPV6_V6ONLY could not be cleared. */
+  GRPC_DSMODE_IPV6,
+  /* AF_INET6, which also supports ::ffff-mapped IPv4 addresses. */
+  GRPC_DSMODE_DUALSTACK
+} grpc_dualstack_mode;
+
+/* Only tests should use this flag. */
+extern int grpc_forbid_dualstack_sockets_for_testing;
+
+/* Creates a new socket for connecting to (or listening on) an address.
+
+   If addr is AF_INET6, this creates an IPv6 socket first.  If that fails,
+   and addr is within ::ffff:0.0.0.0/96, then it automatically falls back to
+   an IPv4 socket.
+
+   If addr is AF_INET, AF_UNIX, or anything else, then this is similar to
+   calling socket() directly.
+
+   Returns an fd on success, otherwise returns -1 with errno set to the result
+   of a failed socket() call.
+
+   The *dsmode output indicates which address family was actually created.
+   The recommended way to use this is:
+   - First convert to IPv6 using grpc_sockaddr_to_v4mapped().
+   - Create the socket.
+   - If *dsmode is IPV4, use grpc_sockaddr_is_v4mapped() to convert back to
+     IPv4, so that bind() or connect() see the correct family.
+   Also, it's important to distinguish between DUALSTACK and IPV6 when
+   listening on the [::] wildcard address. */
+int grpc_create_dualstack_socket(const struct sockaddr *addr, int type,
+                                 int protocol, grpc_dualstack_mode *dsmode);
+
+#endif /* GRPC_INTERNAL_CORE_IOMGR_SOCKET_UTILS_POSIX_H */