1 files changed, 136 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/ip6table_mangle.c b/net/ipv6/netfilter/ip6table_mangle.c
new file mode 100644
index 000000000..a88b2ce4a
--- /dev/null
+++ b/net/ipv6/netfilter/ip6table_mangle.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6
+ *
+ * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
+ * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
+ */
+#include <linux/module.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/slab.h>
+#include <net/ipv6.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("ip6tables mangle table");
+
+#define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
+			    (1 << NF_INET_LOCAL_IN) | \
+			    (1 << NF_INET_FORWARD) | \
+			    (1 << NF_INET_LOCAL_OUT) | \
+			    (1 << NF_INET_POST_ROUTING))
+
+static const struct xt_table packet_mangler = {
+	.name		= "mangle",
+	.valid_hooks	= MANGLE_VALID_HOOKS,
+	.me		= THIS_MODULE,
+	.af		= NFPROTO_IPV6,
+	.priority	= NF_IP6_PRI_MANGLE,
+};
+
+static unsigned int
+ip6t_mangle_out(void *priv, struct sk_buff *skb, const struct nf_hook_state *state)
+{
+	unsigned int ret;
+	struct in6_addr saddr, daddr;
+	u_int8_t hop_limit;
+	u_int32_t flowlabel, mark;
+	int err;
+
+	/* save source/dest address, mark, hoplimit, flowlabel, priority,  */
+	memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
+	memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
+	mark = skb->mark;
+	hop_limit = ipv6_hdr(skb)->hop_limit;
+
+	/* flowlabel and prio (includes version, which shouldn't change either */
+	flowlabel = *((u_int32_t *)ipv6_hdr(skb));
+
+	ret = ip6t_do_table(priv, skb, state);
+
+	if (ret != NF_DROP && ret != NF_STOLEN &&
+	    (!ipv6_addr_equal(&ipv6_hdr(skb)->saddr, &saddr) ||
+	     !ipv6_addr_equal(&ipv6_hdr(skb)->daddr, &daddr) ||
+	     skb->mark != mark ||
+	     ipv6_hdr(skb)->hop_limit != hop_limit ||
+	     flowlabel != *((u_int32_t *)ipv6_hdr(skb)))) {
+		err = ip6_route_me_harder(state->net, state->sk, skb);
+		if (err < 0)
+			ret = NF_DROP_ERR(err);
+	}
+
+	return ret;
+}
+
+/* The work comes in here from netfilter.c. */
+static unsigned int
+ip6table_mangle_hook(void *priv, struct sk_buff *skb,
+		     const struct nf_hook_state *state)
+{
+	if (state->hook == NF_INET_LOCAL_OUT)
+		return ip6t_mangle_out(priv, skb, state);
+	return ip6t_do_table(priv, skb, state);
+}
+
+static struct nf_hook_ops *mangle_ops __read_mostly;
+static int ip6table_mangle_table_init(struct net *net)
+{
+	struct ip6t_replace *repl;
+	int ret;
+
+	repl = ip6t_alloc_initial_table(&packet_mangler);
+	if (repl == NULL)
+		return -ENOMEM;
+	ret = ip6t_register_table(net, &packet_mangler, repl, mangle_ops);
+	kfree(repl);
+	return ret;
+}
+
+static void __net_exit ip6table_mangle_net_pre_exit(struct net *net)
+{
+	ip6t_unregister_table_pre_exit(net, "mangle");
+}
+
+static void __net_exit ip6table_mangle_net_exit(struct net *net)
+{
+	ip6t_unregister_table_exit(net, "mangle");
+}
+
+static struct pernet_operations ip6table_mangle_net_ops = {
+	.pre_exit = ip6table_mangle_net_pre_exit,
+	.exit = ip6table_mangle_net_exit,
+};
+
+static int __init ip6table_mangle_init(void)
+{
+	int ret = xt_register_template(&packet_mangler,
+				       ip6table_mangle_table_init);
+
+	if (ret < 0)
+		return ret;
+
+	mangle_ops = xt_hook_ops_alloc(&packet_mangler, ip6table_mangle_hook);
+	if (IS_ERR(mangle_ops)) {
+		xt_unregister_template(&packet_mangler);
+		return PTR_ERR(mangle_ops);
+	}
+
+	ret = register_pernet_subsys(&ip6table_mangle_net_ops);
+	if (ret < 0) {
+		xt_unregister_template(&packet_mangler);
+		kfree(mangle_ops);
+		return ret;
+	}
+
+	return ret;
+}
+
+static void __exit ip6table_mangle_fini(void)
+{
+	unregister_pernet_subsys(&ip6table_mangle_net_ops);
+	xt_unregister_template(&packet_mangler);
+	kfree(mangle_ops);
+}
+
+module_init(ip6table_mangle_init);
+module_exit(ip6table_mangle_fini);