configure: Add configure script used to detect NaCl

In order to use an installation of NaCl provided by the distro or by
previous manual installation, provide a configure script which checks
for nacl's presence.

Also check of libnl-genl headers. More checks of the other libraries
depended on by netsniff-ng as well as checks for necessary kernel
headers should be added here too.

The configure script is preliminary and has not yet extensively been
tested on multiple systems.

The concept was inspired by the configure script of trinity and
iproute2.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

3 files changed, 103 insertions, 1 deletions

diff --git a/INSTALL b/INSTALL
index a6e2015..3b9b041 100644
--- a/INSTALL
+++ b/INSTALL
@@ -55,8 +55,9 @@ repository root directory:
 
   $ cd netsniff-ng/
 
-The installation (deinstallation) process done by make is fairly simple:
+The installation (deinstallation) process is fairly simple:
 
+  $ ./configure
   $ make
   # make install
 
diff --git a/Makefile b/Makefile
index 8a8b76b..ee03d86 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,8 @@
 # Copyright 2012 - 2013 Daniel Borkmann <borkmann@gnumaniacs.org>
 # Subject to the GNU GPL, version 2.
 
+include Config
+
 VERSION = 0
 PATCHLEVEL = 5
 SUBLEVEL = 8
@@ -203,6 +205,7 @@ install_all: $(foreach tool,$(TOOLS),$(tool)_install)
 install_allbutcurvetun: $(foreach tool,$(filter-out curvetun,$(TOOLS)),$(tool)_install)
 install_allbutmausezahn: $(foreach tool,$(filter-out mausezahn,$(TOOLS)),$(tool)_install)
 clean mostlyclean: $(foreach tool,$(TOOLS),$(tool)_clean)
+	$(Q)$(call RM,Config)
 realclean distclean clobber: $(foreach tool,$(TOOLS),$(tool)_distclean)
 	$(Q)$(call RMDIR,$(ETCDIRE))
 mrproper: clean distclean
diff --git a/configure b/configure
new file mode 100755
index 0000000..fd690ed
--- /dev/null
+++ b/configure
@@ -0,0 +1,98 @@
+#!/bin/bash
+# This isn't a configure generated by autoconf!
+
+MISSING_DEFS=0
+MISSING_NACL=0
+
+[ -z $CC ] && CC=cc
+
+TMPDIR=$(mktemp -d config.XXXXXX)
+trap 'status=$?; rm -rf $TMPDIR; exit $status' EXIT HUP INT QUIT TERM
+
+check_nacl()
+{
+	echo -n "[*] Checking nacl ... "
+
+	cat > $TMPDIR/nacltest.c << EOF
+#include "crypto_hash_sha512.h"
+#include "crypto_verify_32.h"
+#include "crypto_hash_sha512.h"
+#include "crypto_box_curve25519xsalsa20poly1305.h"
+#include "crypto_scalarmult_curve25519.h"
+#include "crypto_auth_hmacsha512256.h"
+
+int main(void) { }
+EOF
+
+	if [ -z $NACL_INC_DIR ] ; then
+		NACL_INC_DIR="/usr/include/nacl"
+	fi
+
+	if [ -z $NACL_LIB_DIR ] ; then
+		NACL_LIB_DIR="/usr/lib"
+	fi
+
+	LDFLAGS="-L $NACL_LIB_DIR"
+	CFLAGS="-I $NACL_INC_DIR"
+
+	$CC $CFLAGS $LDFLAGS -o $TMPDIR/nacltest $TMPDIR/nacltest.c >> $TMPDIR/config.log 2>&1
+	if [ ! -x $TMPDIR/nacltest ] ; then
+		echo "[NO]"
+		MISSING_NACL=1
+	else
+		echo "[YES]"
+		echo "CONFIG_NACL_INC_DIR:=$NACL_INC_DIR" >> Config
+		echo "CONFIG_NACL_LIB_DIR:=$NACL_LIB_DIR" >> Config
+	fi
+
+}
+
+check_libnl()
+{
+	echo -n "[*] Checking libnl ... "
+
+	cat > $TMPDIR/libnltest.c << EOF
+#include <libnl3/netlink/genl/genl.h>
+#include <libnl3/netlink/genl/family.h>
+#include <libnl3/netlink/genl/ctrl.h>
+#include <libnl3/netlink/msg.h>
+#include <libnl3/netlink/attr.h>
+#include <libnl3/netlink/version.h>
+
+#if LIBNL_VER_NUM < LIBNL_VER(3,0)
+# error incompatible libnl version
+#endif
+
+int main(void) { }
+EOF
+
+	$CC $(pkg-config --cflags libnl-3.0) -o $TMPDIR/libnltest $TMPDIR/libnltest.c >> $TMPDIR/config.log 2>&1
+	if [ ! -x $TMPDIR/libnltest ] ; then
+		echo "[NO]"
+		MISSING_DEFS=1
+	else
+		echo "[YES]"
+	fi
+}
+
+echo "# This file is autogenerated by the configure script" > Config
+check_nacl
+check_libnl
+
+if [ "$MISSING_DEFS" == "1" ] ; then
+	echo "[!] Some libraries or header definitions are missing or too old."
+	echo "    Please refer to the INSTALL file for the libraries needed to"
+	echo "    build netsniff-ng."
+	exit 1
+fi
+
+if [ "$MISSING_NACL" == "1" ] ; then
+	echo "[!] The NaCl crypto library is currently not present on your"
+	echo "    system or could not be found. Either install it from your"
+	echo "    distro or build it manually using 'make nacl' and make sure"
+	echo "    that the NACL_INC_DIR and NACL_LIB_DIR variables are set"
+	echo "    appropriately."
+	exit 1
+fi
+
+exit 0