--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/servlib/discovery/IPDiscovery.h	Thu Apr 21 14:57:45 2011 +0100
@@ -0,0 +1,159 @@
+/*
+ *    Copyright 2006 Baylor University
+ * 
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ * 
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#ifndef _IP_DISCOVERY_H_
+#define _IP_DISCOVERY_H_
+
+#include <oasys/thread/Thread.h>
+#include <oasys/thread/Notifier.h>
+#include <oasys/io/NetUtils.h>
+#include <oasys/io/UDPClient.h>
+
+#include "discovery/Discovery.h"
+
+namespace dtn {
+
+/**
+ * IPDiscovery is the main thread in IP-based neighbor discovery,
+ * configured via config file or command console to listen to a specified
+ * UDP port for unicast, broadcast, or multicast beacons from advertising
+ * neighbors.
+ */
+class IPDiscovery : public Discovery,
+                    public oasys::Thread
+{
+public:
+
+    /**
+     * If no other options are set for destination, default to sending 
+     * to the IPv4 broadcast address.
+     */
+    static const u_int32_t DEFAULT_DST_ADDR;
+
+    /**
+     * If no other options are set for source, use this as default
+     * local address
+     */
+    static const u_int32_t DEFAULT_SRC_ADDR;
+
+    /**
+     * If no other options are set for multicast TTL, set to 1
+     */
+    static const u_int DEFAULT_MCAST_TTL;
+
+    /**
+     * On-the-wire (radio, whatever) representation of
+     * IP address family's advertisement beacon
+     */
+    struct DiscoveryHeader
+    {
+        u_int8_t cl_type;         // Type of CL offered
+        u_int8_t interval;        // 100ms units
+        u_int16_t length;         // total length of packet
+        u_int32_t inet_addr;      // IPv4 address of CL
+        u_int16_t inet_port;      // IPv4 port of CL
+        u_int16_t name_len;       // length of EID
+        char sender_name[0];      // DTN URI of beacon sender
+    }
+    __attribute__((packed));
+
+    /**
+     * Enumerate which type of CL is advertised
+     */
+    typedef enum
+    {
+        UNDEFINED = 0,
+        TCPCL     = 1, // TCP Convergence Layer
+        UDPCL     = 2, // UDP Convergence Layer
+    }
+    cl_type_t;
+
+    static const char* type_to_str(cl_type_t t)
+    {
+        switch(t) {
+            case TCPCL: return "tcp";
+            case UDPCL: return "udp";
+            case UNDEFINED:
+            default: PANIC("Undefined cl_type_t %d",t);
+        }
+        NOTREACHED;
+    }
+
+    static cl_type_t str_to_type(const char* cltype)
+    {
+        if (strncmp(cltype,"tcp",3) == 0)
+            return TCPCL;
+        else
+        if (strncmp(cltype,"udp",3) == 0)
+            return UDPCL;
+        else
+            PANIC("Unsupported CL type %s",cltype);
+        NOTREACHED;
+    }
+
+    /**
+     * Close main socket, causing thread to exit
+     */
+    void shutdown() { shutdown_ = true; socket_.get_notifier()->notify(); }
+
+    virtual ~IPDiscovery() {}
+
+protected:
+    friend class Discovery;
+
+    IPDiscovery(const std::string& name);
+
+    /**
+     * Set internal state using parameter list; return true
+     * on success, else false
+     */
+    bool configure(int argc, const char* argv[]);
+
+    /**
+     * virtual from oasys::Thread
+     */
+    void run();
+
+    /**
+     * Convenience method to pull the relevant items out of 
+     * the inbound packet
+     */
+    bool parse_advertisement(u_char* buf, size_t len,
+                             in_addr_t remote_addr,
+                             u_int8_t& cl_type,
+                             std::string& nexthop,
+                             EndpointID& remote_eid);
+
+    /**
+     * Virtual from Discovery
+     */
+    void handle_announce()
+    {
+        socket_.get_notifier()->notify();
+    }
+
+    volatile bool shutdown_; ///< signal to close down thread
+    in_addr_t local_addr_;   ///< address for bind() to receive beacons
+    u_int16_t port_;         ///< local and remote 
+    in_addr_t remote_addr_;  ///< whether unicast, multicast, or broadcast 
+    u_int mcast_ttl_;        ///< TTL hop count for multicast option
+    oasys::UDPClient socket_; ///< the socket for beacons in- and out-bound
+    bool persist_;           ///< whether to exit thread on send/recv failures
+};
+
+} // namespace dtn
+
+#endif /* _IP_DISCOVERY_H_ */