dump: capture in promisc mode by default, with an option to disable it

Change-Id: I75d9580616f0af588291897b27fe376921fef11f
diff --git a/tools/dump/main.cpp b/tools/dump/main.cpp
index 25a0226..ebec765 100644
--- a/tools/dump/main.cpp
+++ b/tools/dump/main.cpp
@@ -73,7 +73,8 @@
                     "read packets from the specified file; use \"-\" to read from standard input")
     ("filter,f",    po::value<std::string>(&nameFilter),
                     "print packet only if name matches this regular expression")
-    ("verbose,v",   po::bool_switch(&instance.isVerbose),
+    ("no-promiscuous-mode,p", po::bool_switch(), "do not put the interface into promiscuous mode")
+    ("verbose,v",   po::bool_switch(&instance.wantVerbose),
                     "print more detailed information about each packet")
     ("version,V",   "print program version and exit")
     ;
@@ -138,6 +139,8 @@
     instance.pcapFilter = os.str();
   }
 
+  instance.wantPromisc = !vm["no-promiscuous-mode"].as<bool>();
+
   try {
     instance.run();
   }