xtables: add xtables-compat-multi for the nftables compatibility layer

This patch should allow distributors to switch to the iptables over
nftables compatibility layer in a transparent way by updating
symbolic links from:

lrwxrwxrwx  1 root    root         13 feb  4 15:35 iptables -> xtables-multi

to:

lrwxrwxrwx  1 root    root         13 feb  4 15:35 iptables -> xtables-compat-multi

Same thing with iptables-save, iptables-restore, ip6tables, ip6tables-save,
ip6tables-restore and arptables.

Note that, after this patch, the following new symlinks are installed:

* iptables-compat
* iptables-compat-save
* iptables-compat-restore
* ip6tables-compat
* ip6tables-compat-save
* ip6tables-compat-restore
* arptables-compat

which point to the new binary xtables-compat-multi.

The idea is to keep both native and compatibility tools installed in the
system, which should also make it easier for testing purposes.

The iptables over nftables compatibility layer is enabled by default
and it requires the libmnl and libnftnl libraries. If you don't want to
compile the compatibility layer, you can still disable it through
--disable-nftables.

This patch also includes changes to adapt the existing code to this
approach.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 25 insertions, 16 deletions

diff --git a/iptables/Makefile.am b/iptables/Makefile.am
index 2c6a163f..41bca7c7 100644
--- a/iptables/Makefile.am
+++ b/iptables/Makefile.am
@@ -25,24 +25,32 @@ endif
 xtables_multi_SOURCES += xshared.c
 xtables_multi_LDADD   += ../libxtables/libxtables.la -lm
 
+# nftables compatibility layer
 if ENABLE_NFTABLES
-if HAVE_LIBMNL
-if HAVE_LIBNFTNL
-xtables_multi_SOURCES += xtables-config-parser.y xtables-config-syntax.l
-xtables_multi_SOURCES += xtables-save.c xtables-restore.c \
-			 xtables-standalone.c xtables.c nft.c \
-			 nft-shared.c nft-ipv4.c nft-ipv6.c nft-arp.c \
-			 xtables-config.c xtables-events.c \
-			 xtables-arp-standalone.c xtables-arp.c
-xtables_multi_LDADD   += ${libmnl_LIBS} ${libnftnl_LIBS}
-xtables_multi_CFLAGS  += -DENABLE_NFTABLES
-# yacc and lex generate dirty code
-xtables_multi-xtables-config-parser.o xtables_multi-xtables-config-syntax.o: AM_CFLAGS += -Wno-missing-prototypes -Wno-missing-declarations -Wno-implicit-function-declaration -Wno-nested-externs -Wno-undef -Wno-redundant-decls
-endif
+xtables_compat_multi_SOURCES  = xtables-compat-multi.c iptables-xml.c
+xtables_compat_multi_CFLAGS   = ${AM_CFLAGS}
+xtables_compat_multi_LDADD    = ../extensions/libext.a
+if ENABLE_STATIC
+xtables_compat_multi_CFLAGS  += -DALL_INCLUSIVE
 endif
+xtables_compat_multi_CFLAGS  += -DENABLE_NFTABLES -DENABLE_IPV4 -DENABLE_IPV6
+xtables_compat_multi_SOURCES += xtables-config-parser.y xtables-config-syntax.l
+xtables_compat_multi_SOURCES += xtables-save.c xtables-restore.c \
+				xtables-standalone.c xtables.c nft.c \
+				nft-shared.c nft-ipv4.c nft-ipv6.c nft-arp.c \
+				xtables-config.c xtables-events.c \
+				xtables-arp-standalone.c xtables-arp.c
+xtables_compat_multi_LDADD   += ${libmnl_LIBS} ${libnftnl_LIBS}
+# yacc and lex generate dirty code
+xtables_compat_multi-xtables-config-parser.o xtables_compat_multi-xtables-config-syntax.o: AM_CFLAGS += -Wno-missing-prototypes -Wno-missing-declarations -Wno-implicit-function-declaration -Wno-nested-externs -Wno-undef -Wno-redundant-decls
+xtables_compat_multi_SOURCES += xshared.c
+xtables_compat_multi_LDADD   += ../libxtables/libxtables.la -lm
 endif
 
 sbin_PROGRAMS    = xtables-multi
+if ENABLE_NFTABLES
+sbin_PROGRAMS	+= xtables-compat-multi
+endif
 man_MANS         = iptables.8 iptables-restore.8 iptables-save.8 \
                    iptables-xml.1 ip6tables.8 ip6tables-restore.8 \
                    ip6tables-save.8 iptables-extensions.8
@@ -57,8 +65,9 @@ if ENABLE_IPV6
 v6_sbin_links  = ip6tables ip6tables-restore ip6tables-save
 endif
 if ENABLE_NFTABLES
-x_sbin_links  = xtables xtables-restore xtables-save xtables-config \
-		xtables-events xtables-arp
+x_sbin_links  = iptables-compat iptables-compat-restore iptables-compat-save \
+		ip6tables-compat ip6tables-compat-restore ip6tables-compat-save \
+		arptables-compat xtables-config xtables-events
 endif
 
 iptables-extensions.8: iptables-extensions.8.tmpl ../extensions/matches.man ../extensions/targets.man
@@ -75,4 +84,4 @@ install-exec-hook:
 	for i in ${vx_bin_links}; do ${LN_S} -f "${sbindir}/xtables-multi" "${DESTDIR}${bindir}/$$i"; done;
 	for i in ${v4_sbin_links}; do ${LN_S} -f xtables-multi "${DESTDIR}${sbindir}/$$i"; done;
 	for i in ${v6_sbin_links}; do ${LN_S} -f xtables-multi "${DESTDIR}${sbindir}/$$i"; done;
-	for i in ${x_sbin_links}; do ${LN_S} -f xtables-multi "${DESTDIR}${sbindir}/$$i"; done;
+	for i in ${x_sbin_links}; do ${LN_S} -f xtables-compat-multi "${DESTDIR}${sbindir}/$$i"; done;