Added session keepalive with retries that will ensure the routes are kept up during high traffic when no proactive NDP soliciations are sent by the sender

ndppd.conf-dist

@@ -38,6 +38,19 @@ proxy eth0 {
 
    autowire no
 
+   # keepalive <yes|no|true|false>
+   # Controls whether ndppd will automatically attempt to keep routing
+   # sessions alive by actively sending out NDP Solicitations before the the
+   # session is expired. The the default value is yes.
+   
+   keepalive yes
+
+   # retries <integer>
+   # Number of times a NDP Solicitation will be sent out before the daemon
+   # considers a route unreachable. The default value is 3
+
+   retries 3
+
    # promiscuous <yes|no|true|false>
    # Controls whether ndppd will put the proxy listening interface into promiscuous
    # mode and hence will react to inbound and outbound NDP commands. This is

src/ndppd.cc

@@ -179,6 +179,16 @@ static bool configure(ptr<conf>& cf)
         else
             pr->autowire(*x_cf);
         
+        if (!(x_cf = pr_cf->find("keepalive")))
+            pr->keepalive(true);
+        else
+            pr->keepalive(*x_cf);
+        
+        if (!(x_cf = pr_cf->find("retries")))
+            pr->retries(3);
+        else
+            pr->retries(*x_cf);
+
         if (!(x_cf = pr_cf->find("ttl")))
             pr->ttl(30000);
         else

src/proxy.cc

@@ -32,7 +32,7 @@ static address all_nodes = address("ff02::1");
 std::list<ptr<proxy> > proxy::_list;
 
 proxy::proxy() :
-    _router(true), _ttl(30000), _deadtime(3000), _timeout(500), _autowire(false), _promiscuous(false)
+    _router(true), _ttl(30000), _deadtime(3000), _timeout(500), _autowire(false), _keepalive(true), _promiscuous(false), _retries(3)
 {
 }
 
@@ -86,7 +86,7 @@ ptr<session> proxy::find_or_create_session(const address& saddr, const address&
         {
             if ((*ad)->addr() == taddr && (*ad)->ifname() == receiver->name())
             {
-                se = session::create(_ptr, saddr, daddr, taddr, _autowire);
+                se = session::create(_ptr, saddr, daddr, taddr, _autowire, _keepalive, _retries);
                 if (se) {
                     se->add_iface(receiver);
                     _sessions.push_back(se);
@@ -118,7 +118,7 @@ ptr<session> proxy::find_or_create_session(const address& saddr, const address&
 
         if (ru->addr() == taddr) {
             if (!se) {
-                se = session::create(_ptr, saddr, daddr, taddr, _autowire);
+                se = session::create(_ptr, saddr, daddr, taddr, _autowire, _keepalive, _retries);
             }
             
             if (ru->is_auto()) {
@@ -258,6 +258,26 @@ void proxy::autowire(bool val)
     _autowire = val;
 }
 
+int proxy::retries() const
+{
+    return _retries;
+}
+
+void proxy::retries(int val)
+{
+    _retries = val;
+}
+
+bool proxy::keepalive() const
+{
+    return _keepalive;
+}
+
+void proxy::keepalive(bool val)
+{
+    _keepalive = val;
+}
+
 int proxy::ttl() const
 {
     return _ttl;

src/proxy.h

@@ -58,6 +58,14 @@ public:
 
     void autowire(bool val);
     
+    int retries() const;
+
+    void retries(int val);
+    
+    bool keepalive() const;
+
+    void keepalive(bool val);
+
     int timeout() const;
 
     void timeout(int val);
@@ -87,6 +95,10 @@ private:
     
     bool _autowire;
     
+    int _retries;
+    
+    bool _keepalive;
+
     int _ttl, _deadtime, _timeout;
 
     proxy();

src/session.cc

@@ -46,20 +46,41 @@ void session::update_all(int elapsed_time)
             
         case session::WAITING:
             logger::debug() << "session is now invalid [taddr=" << se->_taddr << "]";
-            se->_status = session::INVALID;
-            se->_ttl    = se->_pr->deadtime();
+            
+            if (se->_fails < se->_retries) {
+                se->_ttl     = se->_pr->timeout();
+                se->_fails++;
+                
+                // Send another solicit
+                se->send_solicit();
+            } else {
+                se->_status = session::INVALID;
+                se->_ttl    = se->_pr->deadtime();
+            }
             break;
             
         case session::RENEWING:
             logger::debug() << "session is became invalid [taddr=" << se->_taddr << "]";
-            se->_pr->remove_session(se);
+            
+            if (se->_fails < se->_retries) {
+                se->_ttl     = se->_pr->timeout();
+                se->_fails++;
+                
+                // Send another solicit
+                se->send_solicit();
+            } else {            
+                se->_pr->remove_session(se);
+            }
             break;
             
         case session::VALID:            
-            if (se->_touched == true) {
+            if (se->touched() == true ||
+                se->keepalive() == true)
+            {
                 logger::debug() << "session is renewing [taddr=" << se->_taddr << "]";
                 se->_status  = session::RENEWING;
                 se->_ttl     = se->_pr->timeout();
+                se->_fails   = 0;
                 se->_touched = false;
 
                 // Send another solicit to make sure the route is still valid
@@ -94,7 +115,7 @@ session::~session()
 }
 
 ptr<session> session::create(const ptr<proxy>& pr, const address& saddr,
-    const address& daddr, const address& taddr, bool auto_wire)
+    const address& daddr, const address& taddr, bool auto_wire, bool keepalive, int retries)
 {
     ptr<session> se(new session());
 
@@ -104,6 +125,8 @@ ptr<session> session::create(const ptr<proxy>& pr, const address& saddr,
     se->_taddr     = taddr;
     se->_daddr     = daddr;
     se->_autowire  = auto_wire;
+    se->_keepalive = keepalive;
+    se->_retries   = retries;
     se->_wired     = false;
     se->_ttl       = pr->timeout();
     se->_touched   = false;
@@ -112,7 +135,7 @@ ptr<session> session::create(const ptr<proxy>& pr, const address& saddr,
 
     logger::debug()
         << "session::create() pr=" << logger::format("%x", (proxy* )pr) << ", proxy=" << ((pr->ifa()) ? pr->ifa()->name() : "null") << ", saddr=" << saddr
-        << ", daddr=" << daddr << ", taddr=" << taddr << ", autowire=" << (auto_wire == true ? "yes" : "no") << " =" << logger::format("%x", (session* )se);
+        << ", daddr=" << daddr << ", taddr=" << taddr << " =" << logger::format("%x", (session* )se);
 
     return se;
 }
@@ -214,6 +237,7 @@ void session::handle_advert()
     
     _status = VALID;
     _ttl    = _pr->ttl();
+    _fails  = 0;
 
     send_advert();
 }
@@ -238,6 +262,21 @@ bool session::autowire() const
     return _autowire;
 }
 
+bool session::keepalive() const
+{
+    return _keepalive;
+}
+
+int session::retries() const
+{
+    return _retries;
+}
+
+int session::fails() const
+{
+    return _fails;
+}
+
 bool session::wired() const
 {
     return _wired;

src/session.h

@@ -34,6 +34,8 @@ private:
     
     bool _autowire;
     
+    bool _keepalive;
+    
     bool _wired;
     
     bool _touched;
@@ -46,6 +48,10 @@ private:
     // interface's session array or cache.
     int _ttl;
     
+    int _fails;
+    
+    int _retries;
+
     int _status;
 
     static std::list<weak_ptr<session> > _sessions;
@@ -65,7 +71,7 @@ public:
     ~session();
 
     static ptr<session> create(const ptr<proxy>& pr, const address& saddr,
-        const address& daddr, const address& taddr, bool autowire);
+        const address& daddr, const address& taddr, bool autowire, bool keepalive, int retries);
 
     void add_iface(const ptr<iface>& ifa);
 
@@ -77,6 +83,12 @@ public:
     
     bool autowire() const;
     
+    int retries() const;
+    
+    int fails() const;
+
+    bool keepalive() const;
+    
     bool wired() const;
     
     bool touched() const;