Merge remote-tracking branch 'origin/topic/jsiwek/openbsd-support'

* origin/topic/jsiwek/openbsd-support:
  Tweaks for OpenBSD support.

Closes #743.

[I've moved the OpenBSD note about the Makefile into the FAQ. There
might be more stuff to add there over time.]

INSTALL

@@ -66,6 +66,9 @@ except for ``aux/bro-aux`` will also be built and installed by doing
 ``--disable-*`` options that can be given to the configure script to
 turn off unwanted auxiliary projects.
 
+OpenBSD users, please see our `FAQ
+<http://www.bro-ids.org/documentation/faq.html>` if you are having
+problems installing Bro.
 
 Running Bro
 ===========

config.h.in

@@ -32,8 +32,8 @@
 /* Define if you have the <net/ethernet.h> header file. */
 #cmakedefine HAVE_NET_ETHERNET_H
 
-/* We are on a OpenBSD system */
+/* Define if you have the <net/ethertypes.h> header file. */
-#cmakedefine HAVE_OPENBSD
+#cmakedefine HAVE_NET_ETHERTYPES_H
 
 /* have os-proto.h */
 #cmakedefine HAVE_OS_PROTO_H
@@ -145,3 +145,10 @@
 
 /* Define u_int8_t */
 #cmakedefine u_int8_t @u_int8_t@
+
+/* OpenBSD's bpf.h may not declare this data link type, but it's supposed to be
+   used consistently for the same purpose on all platforms. */
+#cmakedefine HAVE_DLT_PPP_SERIAL
+#ifndef HAVE_DLT_PPP_SERIAL
+#define DLT_PPP_SERIAL @DLT_PPP_SERIAL@
+#endif

doc/faq.rst

@@ -52,6 +52,19 @@ That often means that DNS is not set up correctly on the system
 running Bro. Try verifying from the command line that DNS lookups
 work, e.g., ``host www.google.com``.
 
+I am using OpenBSD and having problems installing Bro?
+------------------------------------------------------
+
+One potential issue is that the top-level Makefile may not work with
+OpenBSD's default make program, in which case you can either install
+the ``gmake`` package and use it instead or first change into the
+``build/`` directory before doing either ``make`` or ``make install``
+such that the CMake-generated Makefile's are used directly.
+
+Generally, please note that we do not regularly test OpenBSD builds.
+We appreciate any patches that improve Bro's support for this
+platform.
+
 
 Usage
 =====

src/ARP.h

@@ -15,6 +15,8 @@
 #include <sys/ethernet.h>
 #elif defined(HAVE_NETINET_IF_ETHER_H)
 #include <netinet/if_ether.h>
+#elif defined(HAVE_NET_ETHERTYPES_H)
+#include <net/ethertypes.h>
 #endif
 
 #ifndef arp_pkthdr