From d47ba75b254179f07061dd7782b5d73c9991fdc5 Mon Sep 17 00:00:00 2001 From: Jan Engelhardt Date: Fri, 28 Feb 2025 19:45:01 +0100 Subject: [PATCH] tools: add a systemd unit for static rulesets MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit References: https://lore.kernel.org/netfilter-devel/20250417145055.2700920-1-jengelh@inai.de/ There is a customer request (bugreport) for wanting to trivially load a ruleset from a well-known location on boot, forwarded to me by M. Gerstner. A systemd service unit is hereby added to provide that functionality. This is based on various distributions attempting to do same, for example, https://src.fedoraproject.org/rpms/nftables/tree/rawhide https://gitlab.alpinelinux.org/alpine/aports/-/blob/master/main/nftables/nftables.initd https://gitlab.archlinux.org/archlinux/packaging/packages/nftables Cc: Matthias Gerstner Cc: Kevin Fenzi Cc: Francesco Colista Cc: Sébastien Luttringer --- INSTALL | 6 ++++++ Makefile.am | 16 ++++++++++++---- configure.ac | 10 ++++++++++ files/nftables/main.nft | 22 ++++++++++++++++++++++ tools/nftables.service.8 | 17 +++++++++++++++++ tools/nftables.service.in | 21 +++++++++++++++++++++ 6 files changed, 88 insertions(+), 4 deletions(-) create mode 100644 files/nftables/main.nft create mode 100644 tools/nftables.service.8 create mode 100644 tools/nftables.service.in diff --git a/INSTALL b/INSTALL index 5d45ec98..0c48c989 100644 --- a/INSTALL +++ b/INSTALL @@ -42,6 +42,12 @@ Installation instructions for nftables The base directory for arch-independent files. Defaults to $prefix/share. + --with-unitdir= + + Directory for systemd unit files. Defaults to the value obtained from + pkg-config for systemd.pc, and ${prefix}/lib/systemd/system as a + fallback. + --disable-debug Disable debugging diff --git a/Makefile.am b/Makefile.am index fb64105d..050991f4 100644 --- a/Makefile.am +++ b/Makefile.am @@ -375,18 +375,19 @@ dist_pkgdata_DATA = \ files/nftables/netdev-ingress.nft \ $(NULL) -pkgdocdir = ${docdir}/examples +exampledir = ${docdir}/examples -dist_pkgdoc_SCRIPTS = \ +dist_example_SCRIPTS = \ files/examples/ct_helpers.nft \ files/examples/load_balancing.nft \ files/examples/secmark.nft \ files/examples/sets_and_maps.nft \ $(NULL) -pkgsysconfdir = ${sysconfdir}/nftables/osf +pkgsysconfdir = ${sysconfdir}/${PACKAGE} +osfdir = ${pkgsysconfdir}/osf -dist_pkgsysconf_DATA = \ +dist_osf_DATA = \ files/osf/pf.os \ $(NULL) @@ -410,3 +411,10 @@ EXTRA_DIST += \ pkgconfigdir = $(libdir)/pkgconfig pkgconfig_DATA = libnftables.pc +unit_DATA = tools/nftables.service +man_MANS = tools/nftables.service.8 +doc_DATA = files/nftables/main.nft + +tools/nftables.service: tools/nftables.service.in ${top_builddir}/config.status + ${AM_V_GEN}${MKDIR_P} tools + ${AM_V_at}sed -e 's|@''sbindir''@|${sbindir}|g;s|@''pkgsysconfdir''@|${pkgsysconfdir}|g' <${srcdir}/tools/nftables.service.in >$@ diff --git a/configure.ac b/configure.ac index a4552df7..805af74a 100644 --- a/configure.ac +++ b/configure.ac @@ -114,6 +114,16 @@ AC_CHECK_DECLS([getprotobyname_r, getprotobynumber_r, getservbyport_r], [], [], #include ]]) +AC_ARG_WITH([unitdir], + [AS_HELP_STRING([--with-unitdir=PATH], [Path to systemd service unit directory])], + [unitdir="$withval"], + [ + unitdir=$("$PKG_CONFIG" systemd --variable systemdsystemunitdir 2>/dev/null) + AS_IF([test -z "$unitdir"], [unitdir='${prefix}/lib/systemd/system']) + ]) +AC_SUBST([unitdir]) + + AC_CONFIG_FILES([ \ Makefile \ libnftables.pc \ diff --git a/files/nftables/main.nft b/files/nftables/main.nft new file mode 100644 index 00000000..d3171fd3 --- /dev/null +++ b/files/nftables/main.nft @@ -0,0 +1,22 @@ +#!/usr/sbin/nft -f + +# template static firewall configuration file +# +# copy this over to /etc/nftables/rules/main.nft as a starting point for +# configuring a rule set which will be loaded by nftables.service. + +table inet filter { + chain input { + type filter hook input priority filter; + } + chain forward { + type filter hook forward priority filter; + } + chain output { + type filter hook output priority filter; + } +} + +# this can be used to split the rule set into multiple smaller files concerned +# with specific topics, like forwarding rules +#include "/etc/nftables/rules/forwarding.nft" diff --git a/tools/nftables.service.8 b/tools/nftables.service.8 new file mode 100644 index 00000000..bb88dc46 --- /dev/null +++ b/tools/nftables.service.8 @@ -0,0 +1,17 @@ +.TH nftables.service 8 "" "nftables" "nftables admin reference" +.SH Name +nftables.service \(em Static Firewall Configuration with nftables.service +.SH Description +An nftables systemd service is provided which allows to setup static firewall +rulesets based on a configuration file. +.PP +To use this service, you need to create the main configuration file in +/etc/nftables/rules/main.nft. A template for this can be copied from +/usr/share/doc/nftables/main.nft. Alternatively, `nft list ruleset >main.nft` +could be used to save the active configuration (if any) to the file. +.PP +Once the desired static firewall configuration is in place, it can be tested by +running `systemctl start nftables.service`. To enable the service at boot time, +run `systemctl enable nftables.service`. +.SH See also +\fBnft\fP(8) diff --git a/tools/nftables.service.in b/tools/nftables.service.in new file mode 100644 index 00000000..2ac7e6fd --- /dev/null +++ b/tools/nftables.service.in @@ -0,0 +1,21 @@ +[Unit] +Description=nftables static rule set +Documentation=man:nftables.service(8) +Wants=network-pre.target +Before=network-pre.target shutdown.target +Conflicts=shutdown.target +DefaultDependencies=no +ConditionPathExists=@pkgsysconfdir@/rules/main.nft + +[Service] +Type=oneshot +RemainAfterExit=yes +StandardInput=null +ProtectSystem=full +ProtectHome=true +ExecStart=@sbindir@/nft 'flush ruleset; include "@pkgsysconfdir@/rules/main.nft"' +ExecReload=@sbindir@/nft 'flush ruleset; include "@pkgsysconfdir@/rules/main.nft"' +ExecStop=@sbindir@/nft flush ruleset + +[Install] +WantedBy=sysinit.target -- 2.49.0