arptables-compat: add mangle target extension

This patch adds support to use the mangle target extensions, along with
the required changes in the surrounding code.

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 242 insertions, 8 deletions

diff --git a/extensions/GNUmakefile.in b/extensions/GNUmakefile.in
index 9eb4bf98..4e94bd01 100644
--- a/extensions/GNUmakefile.in
+++ b/extensions/GNUmakefile.in
@@ -40,19 +40,23 @@ endif
 #
 pfx_build_mod := $(patsubst ${srcdir}/libxt_%.c,%,$(sort $(wildcard ${srcdir}/libxt_*.c)))
 pfb_build_mod := $(patsubst ${srcdir}/libebt_%.c,%,$(sort $(wildcard ${srcdir}/libebt_*.c)))
+pfa_build_mod := $(patsubst ${srcdir}/libarpt_%.c,%,$(sort $(wildcard ${srcdir}/libarpt_*.c)))
 pfx_symlinks  := NOTRACK state
 @ENABLE_IPV4_TRUE@ pf4_build_mod := $(patsubst ${srcdir}/libipt_%.c,%,$(sort $(wildcard ${srcdir}/libipt_*.c)))
 @ENABLE_IPV6_TRUE@ pf6_build_mod := $(patsubst ${srcdir}/libip6t_%.c,%,$(sort $(wildcard ${srcdir}/libip6t_*.c)))
 pfx_build_mod := $(filter-out @blacklist_modules@,${pfx_build_mod})
 pfb_build_mod := $(filter-out @blacklist_modules@,${pfb_build_mod})
+pfa_build_mod := $(filter-out @blacklist_modules@,${pfa_build_mod})
 pf4_build_mod := $(filter-out @blacklist_modules@,${pf4_build_mod})
 pf6_build_mod := $(filter-out @blacklist_modules@,${pf6_build_mod})
 pfx_objs      := $(patsubst %,libxt_%.o,${pfx_build_mod})
 pfb_objs      := $(patsubst %,libebt_%.o,${pfb_build_mod})
+pfa_objs      := $(patsubst %,libarpt_%.o,${pfa_build_mod})
 pf4_objs      := $(patsubst %,libipt_%.o,${pf4_build_mod})
 pf6_objs      := $(patsubst %,libip6t_%.o,${pf6_build_mod})
 pfx_solibs    := $(patsubst %,libxt_%.so,${pfx_build_mod} ${pfx_symlinks})
 pfb_solibs    := $(patsubst %,libebt_%.so,${pfb_build_mod})
+pfa_solibs    := $(patsubst %,libarpt_%.so,${pfa_build_mod})
 pf4_solibs    := $(patsubst %,libipt_%.so,${pf4_build_mod})
 pf6_solibs    := $(patsubst %,libip6t_%.so,${pf6_build_mod})
 
@@ -60,14 +64,15 @@ pf6_solibs    := $(patsubst %,libip6t_%.so,${pf6_build_mod})
 #
 # Building blocks
 #
-targets := libext.a libext4.a libext6.a libext_ebt.a matches.man targets.man
+targets := libext.a libext4.a libext6.a libext_ebt.a libext_arpt.a matches.man targets.man
 targets_install :=
 @ENABLE_STATIC_TRUE@ libext_objs := ${pfx_objs}
 @ENABLE_STATIC_TRUE@ libext_ebt_objs := ${pfb_objs}
+@ENABLE_STATIC_TRUE@ libext_arpt_objs := ${pfa_objs}
 @ENABLE_STATIC_TRUE@ libext4_objs := ${pf4_objs}
 @ENABLE_STATIC_TRUE@ libext6_objs := ${pf6_objs}
-@ENABLE_STATIC_FALSE@ targets += ${pfx_solibs} ${pfb_solibs} ${pf4_solibs} ${pf6_solibs}
-@ENABLE_STATIC_FALSE@ targets_install += ${pfx_solibs} ${pfb_solibs} ${pf4_solibs} ${pf6_solibs}
+@ENABLE_STATIC_FALSE@ targets += ${pfx_solibs} ${pfb_solibs} ${pf4_solibs} ${pf6_solibs} ${pfa_solibs}
+@ENABLE_STATIC_FALSE@ targets_install += ${pfx_solibs} ${pfb_solibs} ${pf4_solibs} ${pf6_solibs} ${pfa_solibs}
 
 .SECONDARY:
 
@@ -80,7 +85,7 @@ install: ${targets_install}
 	if test -n "${targets_install}"; then install -pm0755 $^ "${DESTDIR}${xtlibdir}/"; fi;
 
 clean:
-	rm -f *.o *.oo *.so *.a {matches,targets}.man initext.c initext4.c initext6.c initextb.c;
+	rm -f *.o *.oo *.so *.a {matches,targets}.man initext.c initext4.c initext6.c initextb.c initexta.c;
 	rm -f .*.d .*.dd;
 
 distclean: clean
@@ -126,6 +131,9 @@ libext.a: initext.o ${libext_objs}
 libext_ebt.a: initextb.o ${libext_ebt_objs}
 	${AM_VERBOSE_AR} ${AR} crs $@ $^;
 
+libext_arpt.a: initexta.o ${libext_arpt_objs}
+	${AM_VERBOSE_AR} ${AR} crs $@ $^;
+
 libext4.a: initext4.o ${libext4_objs}
 	${AM_VERBOSE_AR} ${AR} crs $@ $^;
 
@@ -134,6 +142,7 @@ libext6.a: initext6.o ${libext6_objs}
 
 initext_func  := $(addprefix xt_,${pfx_build_mod})
 initextb_func := $(addprefix ebt_,${pfb_build_mod})
+initexta_func := $(addprefix arpt_,${pfa_build_mod})
 initext4_func := $(addprefix ipt_,${pf4_build_mod})
 initext6_func := $(addprefix ip6t_,${pf6_build_mod})
 
@@ -147,6 +156,11 @@ initext6_func := $(addprefix ip6t_,${pf6_build_mod})
 	cmp -s $@ $@.tmp || mv $@.tmp $@; \
 	rm -f $@.tmp;
 
+.initexta.dd: FORCE
+	@echo "${initexta_func}" >$@.tmp; \
+	cmp -s $@ $@.tmp || mv $@.tmp $@; \
+	rm -f $@.tmp;
+
 .initext4.dd: FORCE
 	@echo "${initext4_func}" >$@.tmp; \
 	cmp -s $@ $@.tmp || mv $@.tmp $@; \
@@ -189,6 +203,22 @@ initextb.c: .initextb.dd
 	echo "}" >>$@; \
 	);
 
+initexta.c: .initexta.dd
+	${AM_VERBOSE_GEN}
+	@( \
+	echo "" >$@; \
+	for i in ${initexta_func}; do \
+		echo "extern void lib$${i}_init(void);" >>$@; \
+	done; \
+	echo "void init_extensionsa(void);" >>$@; \
+	echo "void init_extensionsa(void)" >>$@; \
+	echo "{" >>$@; \
+	for i in ${initexta_func}; do \
+		echo  " ""lib$${i}_init();" >>$@; \
+	done; \
+	echo "}" >>$@; \
+	);
+
 initext4.c: .initext4.dd
 	${AM_VERBOSE_GEN}
 	@( \
@@ -249,8 +279,8 @@ man_run    = \
 		fi; \
 	done >$@;
 
-matches.man: .initext.dd .initextb.dd .initext4.dd .initext6.dd $(wildcard ${srcdir}/lib*.man)
-	$(call man_run,$(call ex_matches,${pfx_build_mod} ${pfb_build_mod} ${pf4_build_mod} ${pf6_build_mod} ${pfx_symlinks}))
+matches.man: .initext.dd .initextb.dd .initexta.dd .initext4.dd .initext6.dd $(wildcard ${srcdir}/lib*.man)
+	$(call man_run,$(call ex_matches,${pfx_build_mod} ${pfb_build_mod} ${pfa_build_mod} ${pf4_build_mod} ${pf6_build_mod} ${pfx_symlinks}))
 
-targets.man: .initext.dd .initext4.dd .initext6.dd $(wildcard ${srcdir}/lib*.man)
-	$(call man_run,$(call ex_targets,${pfx_build_mod} ${pfb_build_mod} ${pf4_build_mod} ${pf6_build_mod} ${pfx_symlinks}))
+targets.man: .initext.dd .initextb.dd .initexta.dd .initext4.dd .initext6.dd $(wildcard ${srcdir}/lib*.man)
+	$(call man_run,$(call ex_targets,${pfx_build_mod} ${pfb_build_mod} ${pfa_build_mod} ${pf4_build_mod} ${pf6_build_mod} ${pfx_symlinks}))
diff --git a/extensions/libarpt_mangle.c b/extensions/libarpt_mangle.c
new file mode 100644
index 00000000..03c31a94
--- /dev/null
+++ b/extensions/libarpt_mangle.c
@@ -0,0 +1,204 @@
+/*
+ * Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com> adapted
+ * this code to libxtables for arptables-compat in 2015
+ */
+
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <getopt.h>
+#include <netinet/ether.h>
+#include <xtables.h>
+#include <linux/netfilter_arp/arpt_mangle.h>
+#include "iptables/nft.h"
+#include "iptables/nft-arp.h"
+
+static void arpmangle_print_help(void)
+{
+	printf(
+	"mangle target options:\n"
+	"--mangle-ip-s IP address\n"
+	"--mangle-ip-d IP address\n"
+	"--mangle-mac-s MAC address\n"
+	"--mangle-mac-d MAC address\n"
+	"--mangle-target target (DROP, CONTINUE or ACCEPT -- default is ACCEPT)\n");
+}
+
+#define MANGLE_IPS    '1'
+#define MANGLE_IPT    '2'
+#define MANGLE_DEVS   '3'
+#define MANGLE_DEVT   '4'
+#define MANGLE_TARGET '5'
+
+static struct option arpmangle_opts[] = {
+	{ .name = "mangle-ip-s",	.has_arg = true, .val = MANGLE_IPS },
+	{ .name = "mangle-ip-d",	.has_arg = true, .val = MANGLE_IPT },
+	{ .name = "mangle-mac-s",	.has_arg = true, .val = MANGLE_DEVS },
+	{ .name = "mangle-mac-d",	.has_arg = true, .val = MANGLE_DEVT },
+	{ .name = "mangle-target",	.has_arg = true, .val = MANGLE_TARGET },
+	XT_GETOPT_TABLEEND,
+};
+
+static void arpmangle_init(struct xt_entry_target *target)
+{
+	struct arpt_mangle *mangle = (struct arpt_mangle *)target->data;
+
+	mangle->target = NF_ACCEPT;
+}
+
+static int
+arpmangle_parse(int c, char **argv, int invert, unsigned int *flags,
+		const void *entry, struct xt_entry_target **target)
+{
+	struct arpt_mangle *mangle = (struct arpt_mangle *)(*target)->data;
+	struct in_addr *ipaddr, mask;
+	struct ether_addr *macaddr;
+	const struct arpt_entry *e = (const struct arpt_entry *)entry;
+	unsigned int nr;
+	int ret = 1;
+
+	memset(&mask, 0, sizeof(mask));
+
+	switch (c) {
+	case MANGLE_IPS:
+		xtables_ipparse_any(optarg, &ipaddr, &mask, &nr);
+		mangle->u_s.src_ip.s_addr = ipaddr->s_addr;
+		free(ipaddr);
+		mangle->flags |= ARPT_MANGLE_SIP;
+		break;
+	case MANGLE_IPT:
+		xtables_ipparse_any(optarg, &ipaddr, &mask, &nr);
+		mangle->u_t.tgt_ip.s_addr = ipaddr->s_addr;
+		free(ipaddr);
+		mangle->flags |= ARPT_MANGLE_TIP;
+		break;
+	case MANGLE_DEVS:
+		if (e->arp.arhln_mask == 0)
+			xtables_error(PARAMETER_PROBLEM,
+				      "no --h-length defined");
+		if (e->arp.invflags & ARPT_INV_ARPHLN)
+			xtables_error(PARAMETER_PROBLEM,
+				      "! --h-length not allowed for "
+				      "--mangle-mac-s");
+		if (e->arp.arhln != 6)
+			xtables_error(PARAMETER_PROBLEM,
+				      "only --h-length 6 supported");
+		macaddr = ether_aton(optarg);
+		if (macaddr == NULL)
+			xtables_error(PARAMETER_PROBLEM,
+				      "invalid source MAC");
+		memcpy(mangle->src_devaddr, macaddr, e->arp.arhln);
+		mangle->flags |= ARPT_MANGLE_SDEV;
+		break;
+	case MANGLE_DEVT:
+		if (e->arp.arhln_mask == 0)
+			xtables_error(PARAMETER_PROBLEM,
+				      "no --h-length defined");
+		if (e->arp.invflags & ARPT_INV_ARPHLN)
+			xtables_error(PARAMETER_PROBLEM,
+				      "! hln not allowed for --mangle-mac-d");
+		if (e->arp.arhln != 6)
+			xtables_error(PARAMETER_PROBLEM,
+				      "only --h-length 6 supported");
+		macaddr = ether_aton(optarg);
+		if (macaddr == NULL)
+			xtables_error(PARAMETER_PROBLEM, "invalid target MAC");
+		memcpy(mangle->tgt_devaddr, macaddr, e->arp.arhln);
+		mangle->flags |= ARPT_MANGLE_TDEV;
+		break;
+	case MANGLE_TARGET:
+		if (!strcmp(optarg, "DROP"))
+			mangle->target = NF_DROP;
+		else if (!strcmp(optarg, "ACCEPT"))
+			mangle->target = NF_ACCEPT;
+		else if (!strcmp(optarg, "CONTINUE"))
+			mangle->target = XT_CONTINUE;
+		else
+			xtables_error(PARAMETER_PROBLEM,
+				      "bad target for --mangle-target");
+		break;
+	default:
+		ret = 0;
+	}
+
+	return ret;
+}
+
+static void arpmangle_final_check(unsigned int flags)
+{
+}
+
+static void print_mac(const unsigned char *mac, int l)
+{
+	int j;
+
+	for (j = 0; j < l; j++)
+		printf("%02x%s", mac[j],
+			(j==l-1) ? "" : ":");
+}
+
+static void
+arpmangle_print(const void *ip, const struct xt_entry_target *target,
+		int numeric)
+{
+	struct arpt_mangle *m = (struct arpt_mangle *)(target->data);
+	char buf[100];
+
+	if (m->flags & ARPT_MANGLE_SIP) {
+		if (numeric)
+			sprintf(buf, "%s",
+				xtables_ipaddr_to_numeric(&(m->u_s.src_ip)));
+		else
+			sprintf(buf, "%s",
+				xtables_ipaddr_to_anyname(&(m->u_s.src_ip)));
+		printf("--mangle-ip-s %s ", buf);
+	}
+	if (m->flags & ARPT_MANGLE_SDEV) {
+		printf("--mangle-mac-s ");
+		print_mac((unsigned char *)m->src_devaddr, 6);
+		printf(" ");
+	}
+	if (m->flags & ARPT_MANGLE_TIP) {
+		if (numeric)
+			sprintf(buf, "%s",
+				xtables_ipaddr_to_numeric(&(m->u_t.tgt_ip)));
+		else
+			sprintf(buf, "%s",
+				xtables_ipaddr_to_anyname(&(m->u_t.tgt_ip)));
+		printf("--mangle-ip-d %s ", buf);
+	}
+	if (m->flags & ARPT_MANGLE_TDEV) {
+		printf("--mangle-mac-d ");
+		print_mac((unsigned char *)m->tgt_devaddr, 6);
+		printf(" ");
+	}
+	if (m->target != NF_ACCEPT) {
+		printf("--mangle-target ");
+		if (m->target == NF_DROP)
+			printf("DROP ");
+		else
+			printf("CONTINUE ");
+	}
+}
+
+static struct xtables_target arpmangle_target = {
+	.name		= "mangle",
+	.revision	= 0,
+	.version	= XTABLES_VERSION,
+	.family		= NFPROTO_ARP,
+	.size		= XT_ALIGN(sizeof(struct arpt_mangle)),
+	.userspacesize	= XT_ALIGN(sizeof(struct arpt_mangle)),
+	.help		= arpmangle_print_help,
+	.init		= arpmangle_init,
+	.parse		= arpmangle_parse,
+	.final_check	= arpmangle_final_check,
+	.print		= arpmangle_print,
+	.extra_opts	= arpmangle_opts,
+};
+
+void _init(void)
+{
+	xtables_register_target(&arpmangle_target);
+}