[PATCH 15/19] netfilter: ip6tables: add NETMAP target

kaber
2012-08-09T20:23:37Z

From: Patrick McHardy <kaber@trash.net>

Signed-off-by: Patrick McHardy <kaber@trash.net>
---
net/ipv6/netfilter/Kconfig | 10 ++++
net/ipv6/netfilter/Makefile | 1 +
net/ipv6/netfilter/ip6t_NETMAP.c | 94 ++++++++++++++++++++++++++++++++++++++
3 files changed, 105 insertions(+), 0 deletions(-)
create mode 100644 net/ipv6/netfilter/ip6t_NETMAP.c

diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index 585590f..7bdf73b 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -156,6 +156,16 @@ config IP6_NF_TARGET_MASQUERADE

To compile it as a module, choose M here. If unsure, say N.

+config IP6_NF_TARGET_NETMAP
+ tristate "NETMAP target support"
+ depends on NF_NAT_IPV6
+ help
+ NETMAP is an implementation of static 1:1 NAT mapping of network
+ addresses. It maps the network address part, while keeping the host
+ address part intact.
+
+ To compile it as a module, choose M here. If unsure, say N.
+
config IP6_NF_TARGET_REDIRECT
tristate "REDIRECT target support"
depends on NF_NAT_IPV6
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index e30a531..0864ce6 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -35,5 +35,6 @@ obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o

# targets
obj-$(CONFIG_IP6_NF_TARGET_MASQUERADE) += ip6t_MASQUERADE.o
+obj-$(CONFIG_IP6_NF_TARGET_NETMAP) += ip6t_NETMAP.o
obj-$(CONFIG_IP6_NF_TARGET_REDIRECT) += ip6t_REDIRECT.o
obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o
diff --git a/net/ipv6/netfilter/ip6t_NETMAP.c b/net/ipv6/netfilter/ip6t_NETMAP.c
new file mode 100644
index 0000000..4f3bf36
--- /dev/null
+++ b/net/ipv6/netfilter/ip6t_NETMAP.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Based on Svenning Soerensen's IPv4 NETMAP target. Development of IPv6
+ * NAT funded by Astaro.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ipv6.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/netfilter/x_tables.h>
+#include <net/netfilter/nf_nat.h>
+
+static unsigned int
+netmap_tg6(struct sk_buff *skb, const struct xt_action_param *par)
+{
+ const struct nf_nat_range *range = par->targinfo;
+ struct nf_nat_range newrange;
+ struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ union nf_inet_addr new_addr, netmask;
+ unsigned int i;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ for (i = 0; i < ARRAY_SIZE(range->min_addr.ip6); i++)
+ netmask.ip6[i] = ~(range->min_addr.ip6[i] ^
+ range->max_addr.ip6[i]);
+
+ if (par->hooknum == NF_INET_PRE_ROUTING ||
+ par->hooknum == NF_INET_LOCAL_OUT)
+ new_addr.in6 = ipv6_hdr(skb)->daddr;
+ else
+ new_addr.in6 = ipv6_hdr(skb)->saddr;
+
+ for (i = 0; i < ARRAY_SIZE(new_addr.ip6); i++) {
+ new_addr.ip6[i] &= ~netmask.ip6[i];
+ new_addr.ip6[i] |= range->min_addr.ip6[i] &
+ netmask.ip6[i];
+ }
+
+ newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
+ newrange.min_addr = new_addr;
+ newrange.max_addr = new_addr;
+ newrange.min_proto = range->min_proto;
+ newrange.max_proto = range->max_proto;
+
+ return nf_nat_setup_info(ct, &newrange, HOOK2MANIP(par->hooknum));
+}
+
+static int netmap_tg6_checkentry(const struct xt_tgchk_param *par)
+{
+ const struct nf_nat_range *range = par->targinfo;
+
+ if (!(range->flags & NF_NAT_RANGE_MAP_IPS))
+ return -EINVAL;
+ return 0;
+}
+
+static struct xt_target netmap_tg6_reg __read_mostly = {
+ .name = "NETMAP",
+ .family = NFPROTO_IPV6,
+ .target = netmap_tg6,
+ .targetsize = sizeof(struct nf_nat_range),
+ .table = "nat",
+ .hooks = (1 << NF_INET_PRE_ROUTING) |
+ (1 << NF_INET_POST_ROUTING) |
+ (1 << NF_INET_LOCAL_OUT) |
+ (1 << NF_INET_LOCAL_IN),
+ .checkentry = netmap_tg6_checkentry,
+ .me = THIS_MODULE,
+};
+
+static int __init netmap_tg6_init(void)
+{
+ return xt_register_target(&netmap_tg6_reg);
+}
+
+static void netmap_tg6_exit(void)
+{
+ xt_unregister_target(&netmap_tg6_reg);
+}
+
+module_init(netmap_tg6_init);
+module_exit(netmap_tg6_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Xtables: 1:1 NAT mapping of IPv6 subnets");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
--
1.7.1