Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next

Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

The following patchset contains Netfilter/IPVS updates for net-next:

1) Add .release_ops to properly unroll .select_ops, use it from nft_compat.
   After this change, we can remove list of extensions too to simplify this
   codebase.

2) Update amanda conntrack helper to support v3.4, from Florian Tham.

3) Get rid of the obsolete BUGPRINT macro in ebtables, from
   Florian Westphal.

4) Merge IPv4 and IPv6 masquerading infrastructure into one single module.
   From Florian Westphal.

5) Patchset to remove nf_nat_l3proto structure to get rid of
   indirections, from Florian Westphal.

6) Skip unnecessary conntrack timeout updates in case the value is
   still the same, also from Florian Westphal.

7) Remove unnecessary 'fall through' comments in empty switch cases,
   from Li RongQing.

8) Fix lookup to fixed size hashtable sets on big endian with 32-bit keys.

9) Incorrect logic to deactivate path of fixed size hashtable sets,
   element was being tested to self.

10) Remove nft_hash_key(), the bitmap set is always selected for 16-bit
    keys.

11) Use boolean whenever possible in IPVS codebase, from Andrea Claudi.

12) Enter close state in conntrack if RST matches exact sequence number,
    from Florian Westphal.

13) Initialize dst_cache in tunnel extension, from wenxu.

14) Pass protocol as u16 to xt_check_match and xt_check_target, from
    Li RongQing.

15) SCTP header is granted to be in a linear area from IPVS NAT handler,
    from Xin Long.

16) Don't steal packets coming from slave VRF device from the
    ip_sabotage_in() path, from David Ahern.

17) Fix unsafe update of basechain stats, from Li RongQing.

18) Make sure CONNTRACK_LOCKS is power of 2 to let compiler optimize
    modulo operation as bitwise AND, from Li RongQing.

19) Use device_attribute instead of internal definition in the IDLETIMER
    target, from Sami Tolvanen.

20) Merge redir, masq and IPv4/IPv6 NAT chain types, from Florian Westphal.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 362 insertions, 0 deletions

diff --git a/net/netfilter/nf_nat_masquerade.c b/net/netfilter/nf_nat_masquerade.c
new file mode 100644
index 000000000000..86fa4dcc63c5
--- /dev/null
+++ b/net/netfilter/nf_nat_masquerade.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/inetdevice.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv6.h>
+
+#include <net/netfilter/ipv4/nf_nat_masquerade.h>
+#include <net/netfilter/ipv6/nf_nat_masquerade.h>
+
+static DEFINE_MUTEX(masq_mutex);
+static unsigned int masq_refcnt __read_mostly;
+
+unsigned int
+nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum,
+		       const struct nf_nat_range2 *range,
+		       const struct net_device *out)
+{
+	struct nf_conn *ct;
+	struct nf_conn_nat *nat;
+	enum ip_conntrack_info ctinfo;
+	struct nf_nat_range2 newrange;
+	const struct rtable *rt;
+	__be32 newsrc, nh;
+
+	WARN_ON(hooknum != NF_INET_POST_ROUTING);
+
+	ct = nf_ct_get(skb, &ctinfo);
+
+	WARN_ON(!(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
+			 ctinfo == IP_CT_RELATED_REPLY)));
+
+	/* Source address is 0.0.0.0 - locally generated packet that is
+	 * probably not supposed to be masqueraded.
+	 */
+	if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip == 0)
+		return NF_ACCEPT;
+
+	rt = skb_rtable(skb);
+	nh = rt_nexthop(rt, ip_hdr(skb)->daddr);
+	newsrc = inet_select_addr(out, nh, RT_SCOPE_UNIVERSE);
+	if (!newsrc) {
+		pr_info("%s ate my IP address\n", out->name);
+		return NF_DROP;
+	}
+
+	nat = nf_ct_nat_ext_add(ct);
+	if (nat)
+		nat->masq_index = out->ifindex;
+
+	/* Transfer from original range. */
+	memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
+	memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
+	newrange.flags       = range->flags | NF_NAT_RANGE_MAP_IPS;
+	newrange.min_addr.ip = newsrc;
+	newrange.max_addr.ip = newsrc;
+	newrange.min_proto   = range->min_proto;
+	newrange.max_proto   = range->max_proto;
+
+	/* Hand modified range to generic setup. */
+	return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4);
+
+static int device_cmp(struct nf_conn *i, void *ifindex)
+{
+	const struct nf_conn_nat *nat = nfct_nat(i);
+
+	if (!nat)
+		return 0;
+	return nat->masq_index == (int)(long)ifindex;
+}
+
+static int masq_device_event(struct notifier_block *this,
+			     unsigned long event,
+			     void *ptr)
+{
+	const struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct net *net = dev_net(dev);
+
+	if (event == NETDEV_DOWN) {
+		/* Device was downed.  Search entire table for
+		 * conntracks which were associated with that device,
+		 * and forget them.
+		 */
+
+		nf_ct_iterate_cleanup_net(net, device_cmp,
+					  (void *)(long)dev->ifindex, 0, 0);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int inet_cmp(struct nf_conn *ct, void *ptr)
+{
+	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
+	struct net_device *dev = ifa->ifa_dev->dev;
+	struct nf_conntrack_tuple *tuple;
+
+	if (!device_cmp(ct, (void *)(long)dev->ifindex))
+		return 0;
+
+	tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+
+	return ifa->ifa_address == tuple->dst.u3.ip;
+}
+
+static int masq_inet_event(struct notifier_block *this,
+			   unsigned long event,
+			   void *ptr)
+{
+	struct in_device *idev = ((struct in_ifaddr *)ptr)->ifa_dev;
+	struct net *net = dev_net(idev->dev);
+
+	/* The masq_dev_notifier will catch the case of the device going
+	 * down.  So if the inetdev is dead and being destroyed we have
+	 * no work to do.  Otherwise this is an individual address removal
+	 * and we have to perform the flush.
+	 */
+	if (idev->dead)
+		return NOTIFY_DONE;
+
+	if (event == NETDEV_DOWN)
+		nf_ct_iterate_cleanup_net(net, inet_cmp, ptr, 0, 0);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block masq_dev_notifier = {
+	.notifier_call	= masq_device_event,
+};
+
+static struct notifier_block masq_inet_notifier = {
+	.notifier_call	= masq_inet_event,
+};
+
+int nf_nat_masquerade_ipv4_register_notifier(void)
+{
+	int ret = 0;
+
+	mutex_lock(&masq_mutex);
+	/* check if the notifier was already set */
+	if (++masq_refcnt > 1)
+		goto out_unlock;
+
+	/* Register for device down reports */
+	ret = register_netdevice_notifier(&masq_dev_notifier);
+	if (ret)
+		goto err_dec;
+	/* Register IP address change reports */
+	ret = register_inetaddr_notifier(&masq_inet_notifier);
+	if (ret)
+		goto err_unregister;
+
+	mutex_unlock(&masq_mutex);
+	return ret;
+
+err_unregister:
+	unregister_netdevice_notifier(&masq_dev_notifier);
+err_dec:
+	masq_refcnt--;
+out_unlock:
+	mutex_unlock(&masq_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_register_notifier);
+
+void nf_nat_masquerade_ipv4_unregister_notifier(void)
+{
+	mutex_lock(&masq_mutex);
+	/* check if the notifier still has clients */
+	if (--masq_refcnt > 0)
+		goto out_unlock;
+
+	unregister_netdevice_notifier(&masq_dev_notifier);
+	unregister_inetaddr_notifier(&masq_inet_notifier);
+out_unlock:
+	mutex_unlock(&masq_mutex);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_unregister_notifier);
+
+#if IS_ENABLED(CONFIG_IPV6)
+static atomic_t v6_worker_count __read_mostly;
+
+static int
+nat_ipv6_dev_get_saddr(struct net *net, const struct net_device *dev,
+		       const struct in6_addr *daddr, unsigned int srcprefs,
+		       struct in6_addr *saddr)
+{
+#ifdef CONFIG_IPV6_MODULE
+	const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
+
+	if (!v6_ops)
+		return -EHOSTUNREACH;
+
+	return v6_ops->dev_get_saddr(net, dev, daddr, srcprefs, saddr);
+#else
+	return ipv6_dev_get_saddr(net, dev, daddr, srcprefs, saddr);
+#endif
+}
+
+unsigned int
+nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
+		       const struct net_device *out)
+{
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn_nat *nat;
+	struct in6_addr src;
+	struct nf_conn *ct;
+	struct nf_nat_range2 newrange;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	WARN_ON(!(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
+			 ctinfo == IP_CT_RELATED_REPLY)));
+
+	if (nat_ipv6_dev_get_saddr(nf_ct_net(ct), out,
+				   &ipv6_hdr(skb)->daddr, 0, &src) < 0)
+		return NF_DROP;
+
+	nat = nf_ct_nat_ext_add(ct);
+	if (nat)
+		nat->masq_index = out->ifindex;
+
+	newrange.flags		= range->flags | NF_NAT_RANGE_MAP_IPS;
+	newrange.min_addr.in6	= src;
+	newrange.max_addr.in6	= src;
+	newrange.min_proto	= range->min_proto;
+	newrange.max_proto	= range->max_proto;
+
+	return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6);
+
+struct masq_dev_work {
+	struct work_struct work;
+	struct net *net;
+	struct in6_addr addr;
+	int ifindex;
+};
+
+static int inet6_cmp(struct nf_conn *ct, void *work)
+{
+	struct masq_dev_work *w = (struct masq_dev_work *)work;
+	struct nf_conntrack_tuple *tuple;
+
+	if (!device_cmp(ct, (void *)(long)w->ifindex))
+		return 0;
+
+	tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+
+	return ipv6_addr_equal(&w->addr, &tuple->dst.u3.in6);
+}
+
+static void iterate_cleanup_work(struct work_struct *work)
+{
+	struct masq_dev_work *w;
+
+	w = container_of(work, struct masq_dev_work, work);
+
+	nf_ct_iterate_cleanup_net(w->net, inet6_cmp, (void *)w, 0, 0);
+
+	put_net(w->net);
+	kfree(w);
+	atomic_dec(&v6_worker_count);
+	module_put(THIS_MODULE);
+}
+
+/* atomic notifier; can't call nf_ct_iterate_cleanup_net (it can sleep).
+ *
+ * Defer it to the system workqueue.
+ *
+ * As we can have 'a lot' of inet_events (depending on amount of ipv6
+ * addresses being deleted), we also need to limit work item queue.
+ */
+static int masq_inet6_event(struct notifier_block *this,
+			    unsigned long event, void *ptr)
+{
+	struct inet6_ifaddr *ifa = ptr;
+	const struct net_device *dev;
+	struct masq_dev_work *w;
+	struct net *net;
+
+	if (event != NETDEV_DOWN || atomic_read(&v6_worker_count) >= 16)
+		return NOTIFY_DONE;
+
+	dev = ifa->idev->dev;
+	net = maybe_get_net(dev_net(dev));
+	if (!net)
+		return NOTIFY_DONE;
+
+	if (!try_module_get(THIS_MODULE))
+		goto err_module;
+
+	w = kmalloc(sizeof(*w), GFP_ATOMIC);
+	if (w) {
+		atomic_inc(&v6_worker_count);
+
+		INIT_WORK(&w->work, iterate_cleanup_work);
+		w->ifindex = dev->ifindex;
+		w->net = net;
+		w->addr = ifa->addr;
+		schedule_work(&w->work);
+
+		return NOTIFY_DONE;
+	}
+
+	module_put(THIS_MODULE);
+ err_module:
+	put_net(net);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block masq_inet6_notifier = {
+	.notifier_call	= masq_inet6_event,
+};
+
+int nf_nat_masquerade_ipv6_register_notifier(void)
+{
+	int ret = 0;
+
+	mutex_lock(&masq_mutex);
+	/* check if the notifier is already set */
+	if (++masq_refcnt > 1)
+		goto out_unlock;
+
+	ret = register_netdevice_notifier(&masq_dev_notifier);
+	if (ret)
+		goto err_dec;
+
+	ret = register_inet6addr_notifier(&masq_inet6_notifier);
+	if (ret)
+		goto err_unregister;
+
+	mutex_unlock(&masq_mutex);
+	return ret;
+
+err_unregister:
+	unregister_netdevice_notifier(&masq_dev_notifier);
+err_dec:
+	masq_refcnt--;
+out_unlock:
+	mutex_unlock(&masq_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_register_notifier);
+
+void nf_nat_masquerade_ipv6_unregister_notifier(void)
+{
+	mutex_lock(&masq_mutex);
+	/* check if the notifier still has clients */
+	if (--masq_refcnt > 0)
+		goto out_unlock;
+
+	unregister_inet6addr_notifier(&masq_inet6_notifier);
+	unregister_netdevice_notifier(&masq_dev_notifier);
+out_unlock:
+	mutex_unlock(&masq_mutex);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier);
+#endif