UDP networking: The TTL (time to live) was not being set in the IPv4 or IPv6...

UDP networking:  The TTL (time to live) was not being set in the IPv4 or IPv6 header unless the UDP socket was bound.

net/devif/ipv6_forward.c

@@ -106,18 +106,20 @@ static int ipv6_packet_conversion(FAR struct net_driver_s *dev,
         {
           /* Otherwise, we will have to drop the packet */
 
-          nwarn("WARNING: Dropping.  Unsupported 6LoWPAN protocol: %d\n",
+          nwarn("WARNING: Dropping. Unsupported 6LoWPAN protocol: %d\n",
                 ipv6->proto);
 
 #ifdef CONFIG_NET_STATISTICS
           g_netstats.ipv6.drop++;
 #endif
+          return -EPROTONOSUPPORT;
         }
 
       dev->d_len = 0;
       return OK;
     }
 
+  nwarn("WARNING:  Dropping. Unsupported link layer\n");
   return -EPFNOSUPPORT;
 }
 #else
@@ -515,6 +517,7 @@ int ipv6_forward(FAR struct net_driver_s *dev, FAR struct ipv6_hdr_s *ipv6)
   ret = ipv6_decr_ttl(ipv6);
   if (ret < 1)
     {
+      nwarn("WARNING: Hop limit exceeded... Dropping!\n");
       ret = -EMULTIHOP;
       goto drop;
     }
@@ -548,6 +551,7 @@ int ipv6_forward(FAR struct net_driver_s *dev, FAR struct ipv6_hdr_s *ipv6)
       ret = ipv6_dev_forward(dev, fwddev, ipv6);
       if (ret < 0)
         {
+          nwarn("WARNING: ipv6_dev_forward faield: %d\n", ret);
           goto drop;
         }
     }

net/devif/ipv6_input.c

@@ -370,6 +370,7 @@ int ipv6_input(FAR struct net_driver_s *dev)
             {
               /* Not destined for us and not forwardable... drop the packet. */
 
+              nwarn("WARNING: Not destined for us; not forwardable... Dropping!\n");
 #ifdef CONFIG_NET_STATISTICS
               g_netstats.ipv6.drop++;
 #endif

net/udp/udp_conn.c

@@ -457,6 +457,7 @@ FAR struct udp_conn_s *udp_alloc(uint8_t domain)
       conn->domain = domain;
 #endif
       conn->lport  = 0;
+      conn->ttl    = IP_TTL;
 
       /* Enqueue the connection into the active list */
 
@@ -760,7 +761,6 @@ int udp_connect(FAR struct udp_conn_s *conn, FAR const struct sockaddr *addr)
 #endif /* CONFIG_NET_IPv6 */
     }
 
-  conn->ttl = IP_TTL;
   return OK;
 }