Add [overlay] configuration section (experimental):

This configuration section uses the new BasicConfig interface that supports
key-value pairs in the section. Some exposition is added to the example cfg
file. The new settings for overlay are related to the Hub and Spoke feature
which is currently in development. Production servers should not set
these configuration options, they are clearly marked experimental in the
example cfg file.

Conflicts:
	src/ripple/overlay/impl/OverlayImpl.cpp
	src/ripple/overlay/impl/OverlayImpl.h
	src/ripple/overlay/impl/PeerImp.cpp
	src/ripple/overlay/impl/PeerImp.h

doc/rippled-example.cfg

@@ -44,6 +44,41 @@
 #   or Mac style end of lines.  Blank lines and lines beginning with '#' are
 #   ignored. Undefined sections are reserved. No escapes are currently defined.
 #
+# Notation
+#
+#   In this document a simple BNF notation is used. Angle brackets denote
+#   required elements, square brackets denote optional elements, and single
+#   quotes indicate string literals. A vertical bar separating 1 or more
+#   elements is a logical "or"; Any one of the elements may be chosen.
+#   Parenthesis are notational only, and used to group elements, they are not
+#   part of the syntax unless they appear in quotes. White space may always
+#   appear between elements, it has no effect on values.
+#
+#       <key>       A required identifier
+#       '='         The equals sign character
+#       |           Logical "or"
+#       ( )         Used for grouping
+#
+#
+#   An identifier is a string of upper or lower case letters, digits, or
+#   underscores subject to the requirement that the first character of an
+#   identifier must be a letter. Identifiers are not case sensitive (but
+#   values may be).
+#
+#   Some configuration sections contain key/value pairs. A line containing
+#   a key/value pair has this syntax:
+#
+#       <identifier> '=' <value>
+#
+#   Depending on the section and key, different value types are possible:
+#
+#       <integer>   A signed integer
+#       <unsigned>  An unsigned integer
+#       <flag>      A boolean. 1 = true/yes/on, 0 = false/no/off.
+#
+#   Consult the documentation on the key in question to determine the possible
+#   value types.
+#
 #
 #
 #-------------------------------------------------------------------------------
@@ -60,6 +95,38 @@
 #
 #
 #
+# [overlay] EXPERIMENTAL
+#
+#   This section is EXPERIMENTAL, and should not be
+#   present for production configuration settings.
+#
+#   A set of key/value pair parameters to configure the overlay.
+#
+#   auto_connect = 0 | 1
+#
+#       When set, activates the autoconnect feature. This maintains outgoing
+#       connections using the PeerFinder algorithm.
+#
+#   use_handshake = 0 | 1
+#
+#       Use the new HTTP handshaking interface when making outgoing
+#       connections. Incoming HTTP connection handshakes are automatically
+#       detected and switched appropriately.
+#
+#   become_superpeer = 'never' | 'always' | 'auto'
+#
+#       Controls the selection of peer roles:
+#
+#       'never'   Always handshake in the leaf role.
+#       'always'  Always handshake in the superpeer role.
+#       'auto'    Start as a leaf, promote to superpeer after
+#                 passing capability check (default).
+#
+#       Note that in the superpeer role, the IP and port will only be
+#       advertised by other peers if incoming connection tests are succesful.
+#
+#
+#
 # [ips]
 #
 #   List of hostnames or ips where the Ripple protocol is served.  For a starter

src/BeastConfig.h

@@ -220,19 +220,6 @@
 #define RIPPLE_SINGLE_IO_SERVICE_THREAD 0
 #endif
 
-/** Config: RIPPLE_STRUCTURED_OVERLAY_CLIENT
-            RIPPLE_STRUCTURED_OVERLAY_SERVER
-    Enables Structured Overlay support for the client or server roles.
-    This feature is currently in development:
-        https://ripplelabs.atlassian.net/browse/RIPD-157
-*/
-#ifndef RIPPLE_STRUCTURED_OVERLAY_CLIENT
-#define RIPPLE_STRUCTURED_OVERLAY_CLIENT 0
-#endif
-#ifndef RIPPLE_STRUCTURED_OVERLAY_SERVER
-#define RIPPLE_STRUCTURED_OVERLAY_SERVER 1
-#endif
-
 /** Config: RIPPLE_ASYNC_RPC_HANDLER
 */
 #ifndef RIPPLE_ASYNC_RPC_HANDLER

src/ripple/overlay/impl/OverlayImpl.cpp

@@ -71,6 +71,17 @@ OverlayImpl::OverlayImpl (Stoppable& parent,
     , m_resolver (resolver)
     , m_nextShortId (0)
 {
+    auto const& section = getConfig()["overlay"];
+    set (setup_.use_handshake, "use_handshake", section);
+    set (setup_.auto_connect, "auto_connect", section);
+    std::string promote;
+    set (promote, "become_superpeer", section);
+    if (promote == "never")
+        setup_.promote = Promote::never;
+    else if (promote == "always")
+        setup_.promote = Promote::always;
+    else
+        setup_.promote = Promote::automatic;
 }
 
 OverlayImpl::~OverlayImpl ()
@@ -83,6 +94,12 @@ OverlayImpl::~OverlayImpl ()
         return this->m_child_count == 0; });
 }
 
+OverlayImpl::Setup const&
+OverlayImpl::setup() const
+{
+    return setup_;
+}
+
 void
 OverlayImpl::accept (socket_type&& socket)
 {
@@ -436,10 +453,10 @@ OverlayImpl::getActivePeers ()
 
     ret.reserve (m_publicKeyMap.size ());
 
-    for (auto const& pair : m_publicKeyMap)
+    for (auto const& e : m_publicKeyMap)
     {
-        assert (pair.second);
-        ret.push_back (pair.second);
+        assert (e.second);
+        ret.push_back (e.second);
     }
 
     return ret;

src/ripple/overlay/impl/OverlayImpl.h

@@ -52,13 +52,29 @@ private:
     using error_code = boost::system::error_code;
     using yield_context = boost::asio::yield_context;
 
+    enum class Promote
+    {
+        automatic,
+        never,
+        always
+    };
+
+    struct Setup
+    {
+        bool use_handshake = false;
+        bool auto_connect = true;
+        Promote promote = Promote::automatic;
+    };
+
     typedef hash_map <PeerFinder::Slot::ptr,
-                      std::weak_ptr <PeerImp>> PeersBySlot;
+        std::weak_ptr <PeerImp>> PeersBySlot;
 
     typedef hash_map <RippleAddress, Peer::ptr> PeerByPublicKey;
 
     typedef hash_map <Peer::ShortId, Peer::ptr> PeerByShortId;
 
+    Setup setup_;
+
     // VFALCO TODO Change to regular mutex and eliminate re-entrancy
     std::recursive_mutex m_mutex;
 
@@ -114,6 +130,9 @@ public:
     OverlayImpl (OverlayImpl const&) = delete;
     OverlayImpl& operator= (OverlayImpl const&) = delete;
 
+    Setup const&
+    setup() const;
+
     void
     connect (beast::IP::Endpoint const& remote_endpoint) override;