10 files changed, 927 insertions, 0 deletions
diff --git a/src/net/Resolver.cxx b/src/net/Resolver.cxx
new file mode 100644
index 000000000..19df84096
--- /dev/null
+++ b/src/net/Resolver.cxx
@@ -0,0 +1,190 @@
+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "Resolver.hxx"
+#include "SocketAddress.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+
+#include <algorithm>
+
+#ifndef WIN32
+#include <sys/socket.h>
+#include <netdb.h>
+#ifdef HAVE_TCP
+#include <netinet/in.h>
+#endif
+#else
+#include <ws2tcpip.h>
+#include <winsock.h>
+#endif
+
+#ifdef HAVE_UN
+#include <sys/un.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+
+const Domain resolver_domain("resolver");
+
+#ifdef HAVE_UN
+
+static std::string
+LocalAddressToString(const struct sockaddr_un &s_un, size_t size)
+{
+	const size_t prefix_size = (size_t)
+		((struct sockaddr_un *)nullptr)->sun_path;
+	assert(size >= prefix_size);
+
+	size_t result_length = size - prefix_size;
+
+	/* remove the trailing null terminator */
+	if (result_length > 0 && s_un.sun_path[result_length - 1] == 0)
+		--result_length;
+
+	if (result_length == 0)
+		return "local";
+
+	std::string result(s_un.sun_path, result_length);
+
+	/* replace all null bytes with '@'; this also handles abstract
+	   addresses (Linux specific) */
+	std::replace(result.begin(), result.end(), '\0', '@');
+
+	return result;
+}
+
+#endif
+
+std::string
+sockaddr_to_string(SocketAddress address)
+{
+#ifdef HAVE_UN
+	if (address.GetFamily() == AF_UNIX)
+		/* return path of UNIX domain sockets */
+		return LocalAddressToString(*(const sockaddr_un *)address.GetAddress(),
+					    address.GetSize());
+#endif
+
+#if defined(HAVE_IPV6) && defined(IN6_IS_ADDR_V4MAPPED)
+	const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *)
+		address.GetAddress();
+	struct sockaddr_in a4;
+#endif
+	int ret;
+	char host[NI_MAXHOST], serv[NI_MAXSERV];
+
+#if defined(HAVE_IPV6) && defined(IN6_IS_ADDR_V4MAPPED)
+	if (address.GetFamily() == AF_INET6 &&
+	    IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr)) {
+		/* convert "::ffff:127.0.0.1" to "127.0.0.1" */
+
+		memset(&a4, 0, sizeof(a4));
+		a4.sin_family = AF_INET;
+		memcpy(&a4.sin_addr, ((const char *)&a6->sin6_addr) + 12,
+		       sizeof(a4.sin_addr));
+		a4.sin_port = a6->sin6_port;
+
+		address = { (const struct sockaddr *)&a4, sizeof(a4) };
+	}
+#endif
+
+	ret = getnameinfo(address.GetAddress(), address.GetSize(),
+			  host, sizeof(host), serv, sizeof(serv),
+			  NI_NUMERICHOST|NI_NUMERICSERV);
+	if (ret != 0)
+		return "unknown";
+
+#ifdef HAVE_IPV6
+	if (strchr(host, ':') != nullptr) {
+		std::string result("[");
+		result.append(host);
+		result.append("]:");
+		result.append(serv);
+		return result;
+	}
+#endif
+
+	std::string result(host);
+	result.push_back(':');
+	result.append(serv);
+	return result;
+}
+
+struct addrinfo *
+resolve_host_port(const char *host_port, unsigned default_port,
+		  int flags, int socktype,
+		  Error &error)
+{
+	std::string p(host_port);
+	const char *host = p.c_str(), *port = nullptr;
+
+	if (host_port[0] == '[') {
+		/* IPv6 needs enclosing square braces, to
+		   differentiate between IP colons and the port
+		   separator */
+
+		size_t q = p.find(']', 1);
+		if (q != p.npos && p[q + 1] == ':' && p[q + 2] != 0) {
+			p[q] = 0;
+			port = host + q + 2;
+			++host;
+		}
+	}
+
+	if (port == nullptr) {
+		/* port is after the colon, but only if it's the only
+		   colon (don't split IPv6 addresses) */
+
+		auto q = p.find(':');
+		if (q != p.npos && p[q + 1] != 0 &&
+		    p.find(':', q + 1) == p.npos) {
+			p[q] = 0;
+			port = host + q + 1;
+		}
+	}
+
+	char buffer[32];
+	if (port == nullptr && default_port != 0) {
+		snprintf(buffer, sizeof(buffer), "%u", default_port);
+		port = buffer;
+	}
+
+	if ((flags & AI_PASSIVE) != 0 && strcmp(host, "*") == 0)
+		host = nullptr;
+
+	addrinfo hints;
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_flags = flags;
+	hints.ai_family = AF_UNSPEC;
+	hints.ai_socktype = socktype;
+
+	struct addrinfo *ai;
+	int ret = getaddrinfo(host, port, &hints, &ai);
+	if (ret != 0) {
+		error.Format(resolver_domain, ret,
+			     "Failed to look up '%s': %s",
+			     host_port, gai_strerror(ret));
+		return nullptr;
+	}
+
+	return ai;
+}
diff --git a/src/net/Resolver.hxx b/src/net/Resolver.hxx
new file mode 100644
index 000000000..28d2c784b
--- /dev/null
+++ b/src/net/Resolver.hxx
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_RESOLVER_HXX
+#define MPD_RESOLVER_HXX
+
+#include "Compiler.h"
+
+#include <string>
+
+#include <stddef.h>
+
+struct addrinfo;
+class Error;
+class Domain;
+class SocketAddress;
+
+extern const Domain resolver_domain;
+
+/**
+ * Converts the specified socket address into a string in the form
+ * "IP:PORT".
+ */
+gcc_pure
+std::string
+sockaddr_to_string(SocketAddress address);
+
+/**
+ * Resolve a specification in the form "host", "host:port",
+ * "[host]:port".  This is a convenience wrapper for getaddrinfo().
+ *
+ * @param default_port a default port number that will be used if none
+ * is given in the string (if applicable); pass 0 to go without a
+ * default
+ * @return an #addrinfo linked list that must be freed with
+ * freeaddrinfo(), or NULL on error
+ */
+addrinfo *
+resolve_host_port(const char *host_port, unsigned default_port,
+		  int flags, int socktype,
+		  Error &error);
+
+#endif
diff --git a/src/net/SocketAddress.cxx b/src/net/SocketAddress.cxx
new file mode 100644
index 000000000..38aeb8d6d
--- /dev/null
+++ b/src/net/SocketAddress.cxx
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2012-2015 Max Kellermann <max@duempel.org>
+ *
+ * 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.
+ *
+ * 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
+ * FOUNDATION 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 "SocketAddress.hxx"
+
+#include <string.h>
+
+bool
+SocketAddress::operator==(SocketAddress other) const
+{
+	return size == other.size && memcmp(address, other.address, size) == 0;
+}
diff --git a/src/net/SocketAddress.hxx b/src/net/SocketAddress.hxx
new file mode 100644
index 000000000..0577edd72
--- /dev/null
+++ b/src/net/SocketAddress.hxx
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2012-2015 Max Kellermann <max@duempel.org>
+ *
+ * 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.
+ *
+ * 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
+ * FOUNDATION 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 SOCKET_ADDRESS_HXX
+#define SOCKET_ADDRESS_HXX
+
+#include "Compiler.h"
+
+#include <cstddef>
+
+#ifdef WIN32
+#include <winsock2.h>
+#else
+#include <sys/socket.h>
+#endif
+
+/**
+ * An OO wrapper for struct sockaddr.
+ */
+class SocketAddress {
+public:
+#ifdef WIN32
+	typedef int size_type;
+#else
+	typedef socklen_t size_type;
+#endif
+
+private:
+	const struct sockaddr *address;
+	size_type size;
+
+public:
+	SocketAddress() = default;
+
+	constexpr SocketAddress(std::nullptr_t):address(nullptr), size(0) {}
+
+	constexpr SocketAddress(const struct sockaddr *_address,
+				size_type _size)
+		:address(_address), size(_size) {}
+
+	static constexpr SocketAddress Null() {
+		return nullptr;
+	}
+
+	constexpr bool IsNull() const {
+		return address == nullptr;
+	}
+
+	const struct sockaddr *GetAddress() const {
+		return address;
+	}
+
+	constexpr size_type GetSize() const {
+		return size;
+	}
+
+	constexpr int GetFamily() const {
+		return address->sa_family;
+	}
+
+	/**
+	 * Does the object have a well-defined address?  Check !IsNull()
+	 * before calling this method.
+	 */
+	bool IsDefined() const {
+		return GetFamily() != AF_UNSPEC;
+	}
+
+	gcc_pure
+	bool operator==(const SocketAddress other) const;
+
+	bool operator!=(const SocketAddress other) const {
+		return !(*this == other);
+	}
+};
+
+#endif
diff --git a/src/net/SocketError.cxx b/src/net/SocketError.cxx
new file mode 100644
index 000000000..efa969b1f
--- /dev/null
+++ b/src/net/SocketError.cxx
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "SocketError.hxx"
+#include "util/Domain.hxx"
+#include "util/Macros.hxx"
+
+#include <string.h>
+
+const Domain socket_domain("socket");
+
+#ifdef WIN32
+
+SocketErrorMessage::SocketErrorMessage(socket_error_t code)
+{
+#ifdef _UNICODE
+	wchar_t buffer[ARRAY_SIZE(msg)];
+#else
+	auto *buffer = msg;
+#endif
+
+	DWORD nbytes = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
+				     FORMAT_MESSAGE_IGNORE_INSERTS |
+				     FORMAT_MESSAGE_MAX_WIDTH_MASK,
+				     nullptr, code, 0,
+				     buffer, ARRAY_SIZE(msg), nullptr);
+	if (nbytes == 0) {
+		strcpy(msg, "Unknown error");
+		return;
+	}
+
+#ifdef _UNICODE
+	auto length = WideCharToMultiByte(CP_UTF8, 0, buffer, -1,
+					  msg, ARRAY_SIZE(msg),
+					  nullptr, nullptr);
+	if (length <= 0) {
+		strcpy(msg, "WideCharToMultiByte() error");
+		return;
+	}
+#endif
+}
+
+#else
+
+SocketErrorMessage::SocketErrorMessage(socket_error_t code)
+	:msg(strerror(code)) {}
+
+#endif
diff --git a/src/net/SocketError.hxx b/src/net/SocketError.hxx
new file mode 100644
index 000000000..c9435d6fb
--- /dev/null
+++ b/src/net/SocketError.hxx
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_SOCKET_ERROR_HXX
+#define MPD_SOCKET_ERROR_HXX
+
+#include "Compiler.h"
+#include "util/Error.hxx" // IWYU pragma: export
+
+#ifdef WIN32
+#include <winsock2.h>
+typedef DWORD socket_error_t;
+#else
+#include <errno.h>
+typedef int socket_error_t;
+#endif
+
+class Domain;
+
+/**
+ * A #Domain for #Error for socket I/O errors.  The code is an errno
+ * value (or WSAGetLastError() on Windows).
+ */
+extern const Domain socket_domain;
+
+gcc_pure
+static inline socket_error_t
+GetSocketError()
+{
+#ifdef WIN32
+	return WSAGetLastError();
+#else
+	return errno;
+#endif
+}
+
+gcc_const
+static inline bool
+IsSocketErrorAgain(socket_error_t code)
+{
+#ifdef WIN32
+	return code == WSAEINPROGRESS;
+#else
+	return code == EAGAIN;
+#endif
+}
+
+gcc_const
+static inline bool
+IsSocketErrorInterruped(socket_error_t code)
+{
+#ifdef WIN32
+	return code == WSAEINTR;
+#else
+	return code == EINTR;
+#endif
+}
+
+gcc_const
+static inline bool
+IsSocketErrorClosed(socket_error_t code)
+{
+#ifdef WIN32
+	return code == WSAECONNRESET;
+#else
+	return code == EPIPE || code == ECONNRESET;
+#endif
+}
+
+/**
+ * Helper class that formats a socket error message into a
+ * human-readable string.  On Windows, a buffer is necessary for this,
+ * and this class hosts the buffer.
+ */
+class SocketErrorMessage {
+#ifdef WIN32
+	char msg[256];
+#else
+	const char *const msg;
+#endif
+
+public:
+#ifdef WIN32
+	explicit SocketErrorMessage(socket_error_t code=GetSocketError());
+#else
+	explicit SocketErrorMessage(socket_error_t code=GetSocketError());
+#endif
+
+	operator const char *() const {
+		return msg;
+	}
+};
+
+static inline void
+SetSocketError(Error &error, socket_error_t code)
+{
+	const SocketErrorMessage msg(code);
+	error.Set(socket_domain, code, msg);
+}
+
+static inline void
+SetSocketError(Error &error)
+{
+	SetSocketError(error, GetSocketError());
+}
+
+gcc_const
+static inline Error
+NewSocketError(socket_error_t code)
+{
+	Error error;
+	SetSocketError(error, code);
+	return error;
+}
+
+gcc_pure
+static inline Error
+NewSocketError()
+{
+	return NewSocketError(GetSocketError());
+}
+
+#endif
diff --git a/src/net/SocketUtil.cxx b/src/net/SocketUtil.cxx
new file mode 100644
index 000000000..b2ea63985
--- /dev/null
+++ b/src/net/SocketUtil.cxx
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "SocketUtil.hxx"
+#include "SocketAddress.hxx"
+#include "SocketError.hxx"
+#include "system/fd_util.h"
+
+#include <unistd.h>
+
+#ifdef HAVE_IPV6
+#include <string.h>
+#endif
+
+int
+socket_bind_listen(int domain, int type, int protocol,
+		   SocketAddress address,
+		   int backlog,
+		   Error &error)
+{
+	int fd, ret;
+	const int reuse = 1;
+
+	fd = socket_cloexec_nonblock(domain, type, protocol);
+	if (fd < 0) {
+		SetSocketError(error);
+		error.AddPrefix("Failed to create socket: ");
+		return -1;
+	}
+
+	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
+			 (const char *) &reuse, sizeof(reuse));
+	if (ret < 0) {
+		SetSocketError(error);
+		error.AddPrefix("setsockopt() failed: ");
+		close_socket(fd);
+		return -1;
+	}
+
+	ret = bind(fd, address.GetAddress(), address.GetSize());
+	if (ret < 0) {
+		SetSocketError(error);
+		close_socket(fd);
+		return -1;
+	}
+
+	ret = listen(fd, backlog);
+	if (ret < 0) {
+		SetSocketError(error);
+		error.AddPrefix("listen() failed: ");
+		close_socket(fd);
+		return -1;
+	}
+
+#ifdef HAVE_STRUCT_UCRED
+	setsockopt(fd, SOL_SOCKET, SO_PASSCRED,
+		   (const char *) &reuse, sizeof(reuse));
+#endif
+
+	return fd;
+}
+
+int
+socket_keepalive(int fd)
+{
+	const int reuse = 1;
+
+	return setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE,
+			  (const char *)&reuse, sizeof(reuse));
+}
diff --git a/src/net/SocketUtil.hxx b/src/net/SocketUtil.hxx
new file mode 100644
index 000000000..e7f6b8eaa
--- /dev/null
+++ b/src/net/SocketUtil.hxx
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/*
+ * This library provides easy helper functions for working with
+ * sockets.
+ *
+ */
+
+#ifndef MPD_SOCKET_UTIL_HXX
+#define MPD_SOCKET_UTIL_HXX
+
+class SocketAddress;
+class Error;
+
+/**
+ * Creates a socket listening on the specified address.  This is a
+ * shortcut for socket(), bind() and listen().
+ *
+ * @param domain the socket domain, e.g. PF_INET6
+ * @param type the socket type, e.g. SOCK_STREAM
+ * @param protocol the protocol, usually 0 to let the kernel choose
+ * @param address the address to listen on
+ * @param backlog the backlog parameter for the listen() system call
+ * @param error location to store the error occurring, or NULL to
+ * ignore errors
+ * @return the socket file descriptor or -1 on error
+ */
+int
+socket_bind_listen(int domain, int type, int protocol,
+		   SocketAddress address,
+		   int backlog,
+		   Error &error);
+
+int
+socket_keepalive(int fd);
+
+#endif
diff --git a/src/net/StaticSocketAddress.cxx b/src/net/StaticSocketAddress.cxx
new file mode 100644
index 000000000..15e8a9e44
--- /dev/null
+++ b/src/net/StaticSocketAddress.cxx
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2012-2015 Max Kellermann <max@duempel.org>
+ *
+ * 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.
+ *
+ * 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
+ * FOUNDATION 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 "StaticSocketAddress.hxx"
+
+#include <algorithm>
+
+#include <assert.h>
+#include <string.h>
+
+#ifdef WIN32
+#include <ws2tcpip.h>
+#else
+#include <sys/un.h>
+#include <sys/socket.h>
+#endif
+
+StaticSocketAddress &
+StaticSocketAddress::operator=(SocketAddress other)
+{
+	size = std::min(size_t(other.GetSize()), GetCapacity());
+	memcpy(&address, other.GetAddress(), size);
+	return *this;
+}
+
+bool
+StaticSocketAddress::operator==(const StaticSocketAddress &other) const
+{
+	return size == other.size &&
+		memcmp(&address, &other.address, size) == 0;
+}
+
+#ifdef HAVE_UN
+
+void
+StaticSocketAddress::SetLocal(const char *path)
+{
+	auto &sun = reinterpret_cast<struct sockaddr_un &>(address);
+
+	const size_t path_length = strlen(path);
+
+	// TODO: make this a runtime check
+	assert(path_length < sizeof(sun.sun_path));
+
+	sun.sun_family = AF_LOCAL;
+	memcpy(sun.sun_path, path, path_length + 1);
+
+	/* note: Bionic doesn't provide SUN_LEN() */
+	size = SUN_LEN(&sun);
+}
+
+#endif
diff --git a/src/net/StaticSocketAddress.hxx b/src/net/StaticSocketAddress.hxx
new file mode 100644
index 000000000..4e1873a81
--- /dev/null
+++ b/src/net/StaticSocketAddress.hxx
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2012-2015 Max Kellermann <max@duempel.org>
+ *
+ * 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.
+ *
+ * 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
+ * FOUNDATION 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 STATIC_SOCKET_ADDRESS_HXX
+#define STATIC_SOCKET_ADDRESS_HXX
+
+#include "SocketAddress.hxx"
+#include "Compiler.h"
+
+#include <assert.h>
+#include <stdint.h>
+
+#ifdef WIN32
+#include <winsock2.h>
+#else
+#include <sys/socket.h>
+#endif
+
+struct ifaddrs;
+
+/**
+ * An OO wrapper for struct sockaddr_storage.
+ */
+class StaticSocketAddress {
+	size_t size;
+	struct sockaddr_storage address;
+
+public:
+	StaticSocketAddress() = default;
+
+	StaticSocketAddress &operator=(SocketAddress other);
+
+	operator SocketAddress() const {
+		return SocketAddress(reinterpret_cast<const struct sockaddr *>(&address),
+				     size);
+	}
+
+#ifdef HAVE_UN
+	/**
+	 * Make this a "local" address (UNIX domain socket).
+	 */
+	void SetLocal(const char *path);
+#endif
+
+	operator struct sockaddr *() {
+		return reinterpret_cast<struct sockaddr *>(&address);
+	}
+
+	operator const struct sockaddr *() const {
+		return reinterpret_cast<const struct sockaddr *>(&address);
+	}
+
+	constexpr size_t GetCapacity() const {
+		return sizeof(address);
+	}
+
+	size_t GetSize() const {
+		return size;
+	}
+
+	void SetSize(size_t _size) {
+		assert(_size > 0);
+		assert(_size <= sizeof(address));
+
+		size = _size;
+	}
+
+	int GetFamily() const {
+		return address.ss_family;
+	}
+
+	bool IsDefined() const {
+		return GetFamily() != AF_UNSPEC;
+	}
+
+	void Clear() {
+		address.ss_family = AF_UNSPEC;
+	}
+
+	gcc_pure
+	bool operator==(const StaticSocketAddress &other) const;
+
+	bool operator!=(const StaticSocketAddress &other) const {
+		return !(*this == other);
+	}
+};
+
+#endif