netfilter: conntrack: remove l3proto abstraction

This unifies ipv4 and ipv6 protocol trackers and removes the l3proto
abstraction.

This gets rid of all l3proto indirect calls and the need to do
a lookup on the function to call for l3 demux.

It increases module size by only a small amount (12kbyte), so this reduces
size because nf_conntrack.ko is useless without either nf_conntrack_ipv4
or nf_conntrack_ipv6 module.

before:
   text    data     bss     dec     hex filename
   7357    1088       0    8445    20fd nf_conntrack_ipv4.ko
   7405    1084       4    8493    212d nf_conntrack_ipv6.ko
  72614   13689     236   86539   1520b nf_conntrack.ko
 19K nf_conntrack_ipv4.ko
 19K nf_conntrack_ipv6.ko
179K nf_conntrack.ko

after:
   text    data     bss     dec     hex filename
  79277   13937     236   93450   16d0a nf_conntrack.ko
  191K nf_conntrack.ko

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 617 insertions, 230 deletions

diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c
index 39df72bb9d56..803607a90102 100644
--- a/net/netfilter/nf_conntrack_proto.c
+++ b/net/netfilter/nf_conntrack_proto.c
@@ -1,14 +1,4 @@
-/* L3/L4 protocol support for nf_conntrack. */
-
-/* (C) 1999-2001 Paul `Rusty' Russell
- * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
- * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
- * (C) 2006-2012 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.
- */
+// SPDX-License-Identifier: GPL-2.0
 
 #include <linux/types.h>
 #include <linux/netfilter.h>
@@ -24,22 +14,39 @@
 #include <linux/netdevice.h>
 
 #include <net/netfilter/nf_conntrack.h>
-#include <net/netfilter/nf_conntrack_l3proto.h>
 #include <net/netfilter/nf_conntrack_l4proto.h>
 #include <net/netfilter/nf_conntrack_core.h>
 #include <net/netfilter/nf_log.h>
 
+#include <linux/ip.h>
+#include <linux/icmp.h>
+#include <linux/sysctl.h>
+#include <net/route.h>
+#include <net/ip.h>
+
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+#include <net/netfilter/nf_conntrack_seqadj.h>
+#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
+#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
+#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
+
+#include <linux/ipv6.h>
+#include <linux/in6.h>
+#include <net/ipv6.h>
+#include <net/inet_frag.h>
+
+extern unsigned int nf_conntrack_net_id;
+
 static struct nf_conntrack_l4proto __rcu **nf_ct_protos[NFPROTO_NUMPROTO] __read_mostly;
-struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[NFPROTO_NUMPROTO] __read_mostly;
-EXPORT_SYMBOL_GPL(nf_ct_l3protos);
 
 static DEFINE_MUTEX(nf_ct_proto_mutex);
 
-struct nf_conntrack_l3proto nf_conntrack_l3proto_generic __read_mostly = {
-	.l3proto	 = PF_UNSPEC,
-};
-EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_generic);
-
 #ifdef CONFIG_SYSCTL
 static int
 nf_ct_register_sysctl(struct net *net,
@@ -127,137 +134,6 @@ __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
 }
 EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
 
-/* this is guaranteed to always return a valid protocol helper, since
- * it falls back to generic_protocol */
-const struct nf_conntrack_l3proto *
-nf_ct_l3proto_find_get(u_int16_t l3proto)
-{
-	struct nf_conntrack_l3proto *p;
-
-	rcu_read_lock();
-	p = __nf_ct_l3proto_find(l3proto);
-	if (!try_module_get(p->me))
-		p = &nf_conntrack_l3proto_generic;
-	rcu_read_unlock();
-
-	return p;
-}
-EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
-
-int
-nf_ct_l3proto_try_module_get(unsigned short l3proto)
-{
-	const struct nf_conntrack_l3proto *p;
-	int ret;
-
-retry:	p = nf_ct_l3proto_find_get(l3proto);
-	if (p == &nf_conntrack_l3proto_generic) {
-		ret = request_module("nf_conntrack-%d", l3proto);
-		if (!ret)
-			goto retry;
-
-		return -EPROTOTYPE;
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
-
-void nf_ct_l3proto_module_put(unsigned short l3proto)
-{
-	struct nf_conntrack_l3proto *p;
-
-	/* rcu_read_lock not necessary since the caller holds a reference, but
-	 * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find()
-	 */
-	rcu_read_lock();
-	p = __nf_ct_l3proto_find(l3proto);
-	module_put(p->me);
-	rcu_read_unlock();
-}
-EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
-
-static int nf_ct_netns_do_get(struct net *net, u8 nfproto)
-{
-	const struct nf_conntrack_l3proto *l3proto;
-	int ret;
-
-	might_sleep();
-
-	ret = nf_ct_l3proto_try_module_get(nfproto);
-	if (ret < 0)
-		return ret;
-
-	/* we already have a reference, can't fail */
-	rcu_read_lock();
-	l3proto = __nf_ct_l3proto_find(nfproto);
-	rcu_read_unlock();
-
-	if (!l3proto->net_ns_get)
-		return 0;
-
-	ret = l3proto->net_ns_get(net);
-	if (ret < 0)
-		nf_ct_l3proto_module_put(nfproto);
-
-	return ret;
-}
-
-int nf_ct_netns_get(struct net *net, u8 nfproto)
-{
-	int err;
-
-	if (nfproto == NFPROTO_INET) {
-		err = nf_ct_netns_do_get(net, NFPROTO_IPV4);
-		if (err < 0)
-			goto err1;
-		err = nf_ct_netns_do_get(net, NFPROTO_IPV6);
-		if (err < 0)
-			goto err2;
-	} else {
-		err = nf_ct_netns_do_get(net, nfproto);
-		if (err < 0)
-			goto err1;
-	}
-	return 0;
-
-err2:
-	nf_ct_netns_put(net, NFPROTO_IPV4);
-err1:
-	return err;
-}
-EXPORT_SYMBOL_GPL(nf_ct_netns_get);
-
-static void nf_ct_netns_do_put(struct net *net, u8 nfproto)
-{
-	const struct nf_conntrack_l3proto *l3proto;
-
-	might_sleep();
-
-	/* same as nf_conntrack_netns_get(), reference assumed */
-	rcu_read_lock();
-	l3proto = __nf_ct_l3proto_find(nfproto);
-	rcu_read_unlock();
-
-	if (WARN_ON(!l3proto))
-		return;
-
-	if (l3proto->net_ns_put)
-		l3proto->net_ns_put(net);
-
-	nf_ct_l3proto_module_put(nfproto);
-}
-
-void nf_ct_netns_put(struct net *net, uint8_t nfproto)
-{
-	if (nfproto == NFPROTO_INET) {
-		nf_ct_netns_do_put(net, NFPROTO_IPV4);
-		nf_ct_netns_do_put(net, NFPROTO_IPV6);
-	} else
-		nf_ct_netns_do_put(net, nfproto);
-}
-EXPORT_SYMBOL_GPL(nf_ct_netns_put);
-
 const struct nf_conntrack_l4proto *
 nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num)
 {
@@ -279,11 +155,6 @@ void nf_ct_l4proto_put(const struct nf_conntrack_l4proto *p)
 }
 EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
 
-static int kill_l3proto(struct nf_conn *i, void *data)
-{
-	return nf_ct_l3num(i) == ((const struct nf_conntrack_l3proto *)data)->l3proto;
-}
-
 static int kill_l4proto(struct nf_conn *i, void *data)
 {
 	const struct nf_conntrack_l4proto *l4proto;
@@ -292,49 +163,6 @@ static int kill_l4proto(struct nf_conn *i, void *data)
 	       nf_ct_l3num(i) == l4proto->l3proto;
 }
 
-int nf_ct_l3proto_register(const struct nf_conntrack_l3proto *proto)
-{
-	int ret = 0;
-	struct nf_conntrack_l3proto *old;
-
-	if (proto->l3proto >= NFPROTO_NUMPROTO)
-		return -EBUSY;
-
-	mutex_lock(&nf_ct_proto_mutex);
-	old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
-					lockdep_is_held(&nf_ct_proto_mutex));
-	if (old != &nf_conntrack_l3proto_generic) {
-		ret = -EBUSY;
-		goto out_unlock;
-	}
-
-	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
-
-out_unlock:
-	mutex_unlock(&nf_ct_proto_mutex);
-	return ret;
-
-}
-EXPORT_SYMBOL_GPL(nf_ct_l3proto_register);
-
-void nf_ct_l3proto_unregister(const struct nf_conntrack_l3proto *proto)
-{
-	BUG_ON(proto->l3proto >= NFPROTO_NUMPROTO);
-
-	mutex_lock(&nf_ct_proto_mutex);
-	BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
-					 lockdep_is_held(&nf_ct_proto_mutex)
-					 ) != proto);
-	rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
-			   &nf_conntrack_l3proto_generic);
-	mutex_unlock(&nf_ct_proto_mutex);
-
-	synchronize_rcu();
-	/* Remove all contrack entries for this protocol */
-	nf_ct_iterate_destroy(kill_l3proto, (void*)proto);
-}
-EXPORT_SYMBOL_GPL(nf_ct_l3proto_unregister);
-
 static struct nf_proto_net *nf_ct_l4proto_net(struct net *net,
 				const struct nf_conntrack_l4proto *l4proto)
 {
@@ -501,8 +329,23 @@ void nf_ct_l4proto_pernet_unregister_one(struct net *net,
 }
 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister_one);
 
-int nf_ct_l4proto_register(const struct nf_conntrack_l4proto * const l4proto[],
-			   unsigned int num_proto)
+static void
+nf_ct_l4proto_unregister(const struct nf_conntrack_l4proto * const l4proto[],
+			 unsigned int num_proto)
+{
+	mutex_lock(&nf_ct_proto_mutex);
+	while (num_proto-- != 0)
+		__nf_ct_l4proto_unregister_one(l4proto[num_proto]);
+	mutex_unlock(&nf_ct_proto_mutex);
+
+	synchronize_net();
+	/* Remove all contrack entries for this protocol */
+	nf_ct_iterate_destroy(kill_l4proto, (void *)l4proto);
+}
+
+static int
+nf_ct_l4proto_register(const struct nf_conntrack_l4proto * const l4proto[],
+		       unsigned int num_proto)
 {
 	int ret = -EINVAL, ver;
 	unsigned int i;
@@ -520,7 +363,6 @@ int nf_ct_l4proto_register(const struct nf_conntrack_l4proto * const l4proto[],
 	}
 	return ret;
 }
-EXPORT_SYMBOL_GPL(nf_ct_l4proto_register);
 
 int nf_ct_l4proto_pernet_register(struct net *net,
 				  const struct nf_conntrack_l4proto *const l4proto[],
@@ -544,20 +386,6 @@ int nf_ct_l4proto_pernet_register(struct net *net,
 }
 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register);
 
-void nf_ct_l4proto_unregister(const struct nf_conntrack_l4proto * const l4proto[],
-			      unsigned int num_proto)
-{
-	mutex_lock(&nf_ct_proto_mutex);
-	while (num_proto-- != 0)
-		__nf_ct_l4proto_unregister_one(l4proto[num_proto]);
-	mutex_unlock(&nf_ct_proto_mutex);
-
-	synchronize_net();
-	/* Remove all contrack entries for this protocol */
-	nf_ct_iterate_destroy(kill_l4proto, (void *)l4proto);
-}
-EXPORT_SYMBOL_GPL(nf_ct_l4proto_unregister);
-
 void nf_ct_l4proto_pernet_unregister(struct net *net,
 				const struct nf_conntrack_l4proto *const l4proto[],
 				unsigned int num_proto)
@@ -567,6 +395,563 @@ void nf_ct_l4proto_pernet_unregister(struct net *net,
 }
 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister);
 
+static unsigned int ipv4_helper(void *priv,
+				struct sk_buff *skb,
+				const struct nf_hook_state *state)
+{
+	struct nf_conn *ct;
+	enum ip_conntrack_info ctinfo;
+	const struct nf_conn_help *help;
+	const struct nf_conntrack_helper *helper;
+
+	/* This is where we call the helper: as the packet goes out. */
+	ct = nf_ct_get(skb, &ctinfo);
+	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
+		return NF_ACCEPT;
+
+	help = nfct_help(ct);
+	if (!help)
+		return NF_ACCEPT;
+
+	/* rcu_read_lock()ed by nf_hook_thresh */
+	helper = rcu_dereference(help->helper);
+	if (!helper)
+		return NF_ACCEPT;
+
+	return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
+			    ct, ctinfo);
+}
+
+static unsigned int ipv4_confirm(void *priv,
+				 struct sk_buff *skb,
+				 const struct nf_hook_state *state)
+{
+	struct nf_conn *ct;
+	enum ip_conntrack_info ctinfo;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
+		goto out;
+
+	/* adjust seqs for loopback traffic only in outgoing direction */
+	if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
+	    !nf_is_loopback_packet(skb)) {
+		if (!nf_ct_seq_adjust(skb, ct, ctinfo, ip_hdrlen(skb))) {
+			NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
+			return NF_DROP;
+		}
+	}
+out:
+	/* We've seen it coming out the other side: confirm it */
+	return nf_conntrack_confirm(skb);
+}
+
+static unsigned int ipv4_conntrack_in(void *priv,
+				      struct sk_buff *skb,
+				      const struct nf_hook_state *state)
+{
+	return nf_conntrack_in(state->net, PF_INET, state->hook, skb);
+}
+
+static unsigned int ipv4_conntrack_local(void *priv,
+					 struct sk_buff *skb,
+					 const struct nf_hook_state *state)
+{
+	if (ip_is_fragment(ip_hdr(skb))) { /* IP_NODEFRAG setsockopt set */
+		enum ip_conntrack_info ctinfo;
+		struct nf_conn *tmpl;
+
+		tmpl = nf_ct_get(skb, &ctinfo);
+		if (tmpl && nf_ct_is_template(tmpl)) {
+			/* when skipping ct, clear templates to avoid fooling
+			 * later targets/matches
+			 */
+			skb->_nfct = 0;
+			nf_ct_put(tmpl);
+		}
+		return NF_ACCEPT;
+	}
+
+	return nf_conntrack_in(state->net, PF_INET, state->hook, skb);
+}
+
+/* Connection tracking may drop packets, but never alters them, so
+ * make it the first hook.
+ */
+static const struct nf_hook_ops ipv4_conntrack_ops[] = {
+	{
+		.hook		= ipv4_conntrack_in,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_PRE_ROUTING,
+		.priority	= NF_IP_PRI_CONNTRACK,
+	},
+	{
+		.hook		= ipv4_conntrack_local,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_LOCAL_OUT,
+		.priority	= NF_IP_PRI_CONNTRACK,
+	},
+	{
+		.hook		= ipv4_helper,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_POST_ROUTING,
+		.priority	= NF_IP_PRI_CONNTRACK_HELPER,
+	},
+	{
+		.hook		= ipv4_confirm,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_POST_ROUTING,
+		.priority	= NF_IP_PRI_CONNTRACK_CONFIRM,
+	},
+	{
+		.hook		= ipv4_helper,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_LOCAL_IN,
+		.priority	= NF_IP_PRI_CONNTRACK_HELPER,
+	},
+	{
+		.hook		= ipv4_confirm,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_LOCAL_IN,
+		.priority	= NF_IP_PRI_CONNTRACK_CONFIRM,
+	},
+};
+
+/* Fast function for those who don't want to parse /proc (and I don't
+ * blame them).
+ * Reversing the socket's dst/src point of view gives us the reply
+ * mapping.
+ */
+static int
+getorigdst(struct sock *sk, int optval, void __user *user, int *len)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct nf_conntrack_tuple_hash *h;
+	struct nf_conntrack_tuple tuple;
+
+	memset(&tuple, 0, sizeof(tuple));
+
+	lock_sock(sk);
+	tuple.src.u3.ip = inet->inet_rcv_saddr;
+	tuple.src.u.tcp.port = inet->inet_sport;
+	tuple.dst.u3.ip = inet->inet_daddr;
+	tuple.dst.u.tcp.port = inet->inet_dport;
+	tuple.src.l3num = PF_INET;
+	tuple.dst.protonum = sk->sk_protocol;
+	release_sock(sk);
+
+	/* We only do TCP and SCTP at the moment: is there a better way? */
+	if (tuple.dst.protonum != IPPROTO_TCP &&
+	    tuple.dst.protonum != IPPROTO_SCTP) {
+		pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
+		return -ENOPROTOOPT;
+	}
+
+	if ((unsigned int)*len < sizeof(struct sockaddr_in)) {
+		pr_debug("SO_ORIGINAL_DST: len %d not %zu\n",
+			 *len, sizeof(struct sockaddr_in));
+		return -EINVAL;
+	}
+
+	h = nf_conntrack_find_get(sock_net(sk), &nf_ct_zone_dflt, &tuple);
+	if (h) {
+		struct sockaddr_in sin;
+		struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
+
+		sin.sin_family = AF_INET;
+		sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
+			.tuple.dst.u.tcp.port;
+		sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
+			.tuple.dst.u3.ip;
+		memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
+
+		pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
+			 &sin.sin_addr.s_addr, ntohs(sin.sin_port));
+		nf_ct_put(ct);
+		if (copy_to_user(user, &sin, sizeof(sin)) != 0)
+			return -EFAULT;
+		else
+			return 0;
+	}
+	pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
+		 &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port),
+		 &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port));
+	return -ENOENT;
+}
+
+static struct nf_sockopt_ops so_getorigdst = {
+	.pf		= PF_INET,
+	.get_optmin	= SO_ORIGINAL_DST,
+	.get_optmax	= SO_ORIGINAL_DST + 1,
+	.get		= getorigdst,
+	.owner		= THIS_MODULE,
+};
+
+#if IS_ENABLED(CONFIG_IPV6)
+static int
+ipv6_getorigdst(struct sock *sk, int optval, void __user *user, int *len)
+{
+	struct nf_conntrack_tuple tuple = { .src.l3num = NFPROTO_IPV6 };
+	const struct ipv6_pinfo *inet6 = inet6_sk(sk);
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct nf_conntrack_tuple_hash *h;
+	struct sockaddr_in6 sin6;
+	struct nf_conn *ct;
+	__be32 flow_label;
+	int bound_dev_if;
+
+	lock_sock(sk);
+	tuple.src.u3.in6 = sk->sk_v6_rcv_saddr;
+	tuple.src.u.tcp.port = inet->inet_sport;
+	tuple.dst.u3.in6 = sk->sk_v6_daddr;
+	tuple.dst.u.tcp.port = inet->inet_dport;
+	tuple.dst.protonum = sk->sk_protocol;
+	bound_dev_if = sk->sk_bound_dev_if;
+	flow_label = inet6->flow_label;
+	release_sock(sk);
+
+	if (tuple.dst.protonum != IPPROTO_TCP &&
+	    tuple.dst.protonum != IPPROTO_SCTP)
+		return -ENOPROTOOPT;
+
+	if (*len < 0 || (unsigned int)*len < sizeof(sin6))
+		return -EINVAL;
+
+	h = nf_conntrack_find_get(sock_net(sk), &nf_ct_zone_dflt, &tuple);
+	if (!h) {
+		pr_debug("IP6T_SO_ORIGINAL_DST: Can't find %pI6c/%u-%pI6c/%u.\n",
+			 &tuple.src.u3.ip6, ntohs(tuple.src.u.tcp.port),
+			 &tuple.dst.u3.ip6, ntohs(tuple.dst.u.tcp.port));
+		return -ENOENT;
+	}
+
+	ct = nf_ct_tuplehash_to_ctrack(h);
+
+	sin6.sin6_family = AF_INET6;
+	sin6.sin6_port = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.tcp.port;
+	sin6.sin6_flowinfo = flow_label & IPV6_FLOWINFO_MASK;
+	memcpy(&sin6.sin6_addr,
+	       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.in6,
+	       sizeof(sin6.sin6_addr));
+
+	nf_ct_put(ct);
+	sin6.sin6_scope_id = ipv6_iface_scope_id(&sin6.sin6_addr, bound_dev_if);
+	return copy_to_user(user, &sin6, sizeof(sin6)) ? -EFAULT : 0;
+}
+
+static struct nf_sockopt_ops so_getorigdst6 = {
+	.pf		= NFPROTO_IPV6,
+	.get_optmin	= IP6T_SO_ORIGINAL_DST,
+	.get_optmax	= IP6T_SO_ORIGINAL_DST + 1,
+	.get		= ipv6_getorigdst,
+	.owner		= THIS_MODULE,
+};
+
+static unsigned int ipv6_confirm(void *priv,
+				 struct sk_buff *skb,
+				 const struct nf_hook_state *state)
+{
+	struct nf_conn *ct;
+	enum ip_conntrack_info ctinfo;
+	unsigned char pnum = ipv6_hdr(skb)->nexthdr;
+	int protoff;
+	__be16 frag_off;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
+		goto out;
+
+	protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
+				   &frag_off);
+	if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
+		pr_debug("proto header not found\n");
+		goto out;
+	}
+
+	/* adjust seqs for loopback traffic only in outgoing direction */
+	if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
+	    !nf_is_loopback_packet(skb)) {
+		if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
+			NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
+			return NF_DROP;
+		}
+	}
+out:
+	/* We've seen it coming out the other side: confirm it */
+	return nf_conntrack_confirm(skb);
+}
+
+static unsigned int ipv6_conntrack_in(void *priv,
+				      struct sk_buff *skb,
+				      const struct nf_hook_state *state)
+{
+	return nf_conntrack_in(state->net, PF_INET6, state->hook, skb);
+}
+
+static unsigned int ipv6_conntrack_local(void *priv,
+					 struct sk_buff *skb,
+					 const struct nf_hook_state *state)
+{
+	return nf_conntrack_in(state->net, PF_INET6, state->hook, skb);
+}
+
+static unsigned int ipv6_helper(void *priv,
+				struct sk_buff *skb,
+				const struct nf_hook_state *state)
+{
+	struct nf_conn *ct;
+	const struct nf_conn_help *help;
+	const struct nf_conntrack_helper *helper;
+	enum ip_conntrack_info ctinfo;
+	__be16 frag_off;
+	int protoff;
+	u8 nexthdr;
+
+	/* This is where we call the helper: as the packet goes out. */
+	ct = nf_ct_get(skb, &ctinfo);
+	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
+		return NF_ACCEPT;
+
+	help = nfct_help(ct);
+	if (!help)
+		return NF_ACCEPT;
+	/* rcu_read_lock()ed by nf_hook_thresh */
+	helper = rcu_dereference(help->helper);
+	if (!helper)
+		return NF_ACCEPT;
+
+	nexthdr = ipv6_hdr(skb)->nexthdr;
+	protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
+				   &frag_off);
+	if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
+		pr_debug("proto header not found\n");
+		return NF_ACCEPT;
+	}
+
+	return helper->help(skb, protoff, ct, ctinfo);
+}
+
+static const struct nf_hook_ops ipv6_conntrack_ops[] = {
+	{
+		.hook		= ipv6_conntrack_in,
+		.pf		= NFPROTO_IPV6,
+		.hooknum	= NF_INET_PRE_ROUTING,
+		.priority	= NF_IP6_PRI_CONNTRACK,
+	},
+	{
+		.hook		= ipv6_conntrack_local,
+		.pf		= NFPROTO_IPV6,
+		.hooknum	= NF_INET_LOCAL_OUT,
+		.priority	= NF_IP6_PRI_CONNTRACK,
+	},
+	{
+		.hook		= ipv6_helper,
+		.pf		= NFPROTO_IPV6,
+		.hooknum	= NF_INET_POST_ROUTING,
+		.priority	= NF_IP6_PRI_CONNTRACK_HELPER,
+	},
+	{
+		.hook		= ipv6_confirm,
+		.pf		= NFPROTO_IPV6,
+		.hooknum	= NF_INET_POST_ROUTING,
+		.priority	= NF_IP6_PRI_LAST,
+	},
+	{
+		.hook		= ipv6_helper,
+		.pf		= NFPROTO_IPV6,
+		.hooknum	= NF_INET_LOCAL_IN,
+		.priority	= NF_IP6_PRI_CONNTRACK_HELPER,
+	},
+	{
+		.hook		= ipv6_confirm,
+		.pf		= NFPROTO_IPV6,
+		.hooknum	= NF_INET_LOCAL_IN,
+		.priority	= NF_IP6_PRI_LAST - 1,
+	},
+};
+#endif
+
+static int nf_ct_netns_do_get(struct net *net, u8 nfproto)
+{
+	struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
+	int err = 0;
+
+	mutex_lock(&nf_ct_proto_mutex);
+
+	switch (nfproto) {
+	case NFPROTO_IPV4:
+		cnet->users4++;
+		if (cnet->users4 > 1)
+			goto out_unlock;
+		err = nf_defrag_ipv4_enable(net);
+		if (err) {
+			cnet->users4 = 0;
+			goto out_unlock;
+		}
+
+		err = nf_register_net_hooks(net, ipv4_conntrack_ops,
+					    ARRAY_SIZE(ipv4_conntrack_ops));
+		if (err)
+			cnet->users4 = 0;
+		break;
+#if IS_ENABLED(CONFIG_IPV6)
+	case NFPROTO_IPV6:
+		cnet->users6++;
+		if (cnet->users6 > 1)
+			goto out_unlock;
+		err = nf_defrag_ipv6_enable(net);
+		if (err < 0) {
+			cnet->users6 = 0;
+			goto out_unlock;
+		}
+
+		err = nf_register_net_hooks(net, ipv6_conntrack_ops,
+					    ARRAY_SIZE(ipv6_conntrack_ops));
+		if (err)
+			cnet->users6 = 0;
+		break;
+#endif
+	default:
+		err = -EPROTO;
+		break;
+	}
+ out_unlock:
+	mutex_unlock(&nf_ct_proto_mutex);
+	return err;
+}
+
+static void nf_ct_netns_do_put(struct net *net, u8 nfproto)
+{
+	struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
+
+	mutex_lock(&nf_ct_proto_mutex);
+	switch (nfproto) {
+	case NFPROTO_IPV4:
+		if (cnet->users4 && (--cnet->users4 == 0))
+			nf_unregister_net_hooks(net, ipv4_conntrack_ops,
+						ARRAY_SIZE(ipv4_conntrack_ops));
+		break;
+#if IS_ENABLED(CONFIG_IPV6)
+	case NFPROTO_IPV6:
+		if (cnet->users6 && (--cnet->users6 == 0))
+			nf_unregister_net_hooks(net, ipv6_conntrack_ops,
+						ARRAY_SIZE(ipv6_conntrack_ops));
+		break;
+#endif
+	}
+
+	mutex_unlock(&nf_ct_proto_mutex);
+}
+
+int nf_ct_netns_get(struct net *net, u8 nfproto)
+{
+	int err;
+
+	if (nfproto == NFPROTO_INET) {
+		err = nf_ct_netns_do_get(net, NFPROTO_IPV4);
+		if (err < 0)
+			goto err1;
+		err = nf_ct_netns_do_get(net, NFPROTO_IPV6);
+		if (err < 0)
+			goto err2;
+	} else {
+		err = nf_ct_netns_do_get(net, nfproto);
+		if (err < 0)
+			goto err1;
+	}
+	return 0;
+
+err2:
+	nf_ct_netns_put(net, NFPROTO_IPV4);
+err1:
+	return err;
+}
+EXPORT_SYMBOL_GPL(nf_ct_netns_get);
+
+void nf_ct_netns_put(struct net *net, uint8_t nfproto)
+{
+	if (nfproto == NFPROTO_INET) {
+		nf_ct_netns_do_put(net, NFPROTO_IPV4);
+		nf_ct_netns_do_put(net, NFPROTO_IPV6);
+	} else {
+		nf_ct_netns_do_put(net, nfproto);
+	}
+}
+EXPORT_SYMBOL_GPL(nf_ct_netns_put);
+
+static const struct nf_conntrack_l4proto * const builtin_l4proto[] = {
+	&nf_conntrack_l4proto_tcp4,
+	&nf_conntrack_l4proto_udp4,
+	&nf_conntrack_l4proto_icmp,
+#ifdef CONFIG_NF_CT_PROTO_DCCP
+	&nf_conntrack_l4proto_dccp4,
+#endif
+#ifdef CONFIG_NF_CT_PROTO_SCTP
+	&nf_conntrack_l4proto_sctp4,
+#endif
+#ifdef CONFIG_NF_CT_PROTO_UDPLITE
+	&nf_conntrack_l4proto_udplite4,
+#endif
+#if IS_ENABLED(CONFIG_IPV6)
+	&nf_conntrack_l4proto_tcp6,
+	&nf_conntrack_l4proto_udp6,
+	&nf_conntrack_l4proto_icmpv6,
+#ifdef CONFIG_NF_CT_PROTO_DCCP
+	&nf_conntrack_l4proto_dccp6,
+#endif
+#ifdef CONFIG_NF_CT_PROTO_SCTP
+	&nf_conntrack_l4proto_sctp6,
+#endif
+#ifdef CONFIG_NF_CT_PROTO_UDPLITE
+	&nf_conntrack_l4proto_udplite6,
+#endif
+#endif /* CONFIG_IPV6 */
+};
+
+int nf_conntrack_proto_init(void)
+{
+	int ret = 0;
+
+	ret = nf_register_sockopt(&so_getorigdst);
+	if (ret < 0)
+		return ret;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	ret = nf_register_sockopt(&so_getorigdst6);
+	if (ret < 0)
+		goto cleanup_sockopt;
+#endif
+	ret = nf_ct_l4proto_register(builtin_l4proto,
+				     ARRAY_SIZE(builtin_l4proto));
+	if (ret < 0)
+		goto cleanup_sockopt2;
+
+	return ret;
+cleanup_sockopt2:
+	nf_unregister_sockopt(&so_getorigdst);
+#if IS_ENABLED(CONFIG_IPV6)
+cleanup_sockopt:
+	nf_unregister_sockopt(&so_getorigdst6);
+#endif
+	return ret;
+}
+
+void nf_conntrack_proto_fini(void)
+{
+	unsigned int i;
+
+	nf_ct_l4proto_unregister(builtin_l4proto,
+				 ARRAY_SIZE(builtin_l4proto));
+	nf_unregister_sockopt(&so_getorigdst);
+#if IS_ENABLED(CONFIG_IPV6)
+	nf_unregister_sockopt(&so_getorigdst6);
+#endif
+
+	/* free l3proto protocol tables */
+	for (i = 0; i < ARRAY_SIZE(nf_ct_protos); i++)
+		kfree(nf_ct_protos[i]);
+}
+
 int nf_conntrack_proto_pernet_init(struct net *net)
 {
 	int err;
@@ -583,6 +968,14 @@ int nf_conntrack_proto_pernet_init(struct net *net)
 	if (err < 0)
 		return err;
 
+	err = nf_ct_l4proto_pernet_register(net, builtin_l4proto,
+					    ARRAY_SIZE(builtin_l4proto));
+	if (err < 0) {
+		nf_ct_l4proto_unregister_sysctl(net, pn,
+						&nf_conntrack_l4proto_generic);
+		return err;
+	}
+
 	pn->users++;
 	return 0;
 }
@@ -592,25 +985,19 @@ void nf_conntrack_proto_pernet_fini(struct net *net)
 	struct nf_proto_net *pn = nf_ct_l4proto_net(net,
 					&nf_conntrack_l4proto_generic);
 
+	nf_ct_l4proto_pernet_unregister(net, builtin_l4proto,
+					ARRAY_SIZE(builtin_l4proto));
 	pn->users--;
 	nf_ct_l4proto_unregister_sysctl(net,
 					pn,
 					&nf_conntrack_l4proto_generic);
 }
 
-int nf_conntrack_proto_init(void)
-{
-	unsigned int i;
-	for (i = 0; i < NFPROTO_NUMPROTO; i++)
-		rcu_assign_pointer(nf_ct_l3protos[i],
-				   &nf_conntrack_l3proto_generic);
-	return 0;
-}
 
-void nf_conntrack_proto_fini(void)
-{
-	unsigned int i;
-	/* free l3proto protocol tables */
-	for (i = 0; i < ARRAY_SIZE(nf_ct_protos); i++)
-		kfree(nf_ct_protos[i]);
-}
+module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
+		  &nf_conntrack_htable_size, 0600);
+
+MODULE_ALIAS("ip_conntrack");
+MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
+MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6));
+MODULE_LICENSE("GPL");