diff --git a/tools/dump/wscript b/tools/dump/wscript
index cd9971b..df23de9 100644
--- a/tools/dump/wscript
+++ b/tools/dump/wscript
@@ -4,6 +4,14 @@
 def configure(conf):
     conf.check_cfg(package='libpcap', uselib_store='PCAP',
                    path='pcap-config', args='--libs --cflags')
+    conf.check_cxx(msg='Checking if struct tcphdr has member th_off ',
+                   define_name='HAVE_BSD_TCPHDR', mandatory=False,
+                   fragment='''#include <netinet/tcp.h>
+                               int main() { tcphdr th; th.th_off; }''')
+    conf.check_cxx(msg='Checking if struct udphdr has member uh_ulen',
+                   define_name='HAVE_BSD_UDPHDR', mandatory=False,
+                   fragment='''#include <netinet/udp.h>
+                               int main() { udphdr uh; uh.uh_ulen; }''')
 
 def build(bld):
     bld.objects(