1 files changed, 619 insertions, 0 deletions

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
new file mode 100644
index 000000000..dacdea7fc
--- /dev/null
+++ b/net/ipv6/anycast.c
@@ -0,0 +1,619 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Anycast support for IPv6
+ *	Linux INET6 implementation
+ *
+ *	Authors:
+ *	David L Stevens (dlstevens@us.ibm.com)
+ *
+ *	based heavily on net/ipv6/mcast.c
+ */
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/random.h>
+#include <linux/string.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/in6.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/route.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/if_inet6.h>
+#include <net/ndisc.h>
+#include <net/addrconf.h>
+#include <net/ip6_route.h>
+
+#include <net/checksum.h>
+
+#define IN6_ADDR_HSIZE_SHIFT	8
+#define IN6_ADDR_HSIZE		BIT(IN6_ADDR_HSIZE_SHIFT)
+/*	anycast address hash table
+ */
+static struct hlist_head inet6_acaddr_lst[IN6_ADDR_HSIZE];
+static DEFINE_SPINLOCK(acaddr_hash_lock);
+
+static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr);
+
+static u32 inet6_acaddr_hash(struct net *net, const struct in6_addr *addr)
+{
+	u32 val = ipv6_addr_hash(addr) ^ net_hash_mix(net);
+
+	return hash_32(val, IN6_ADDR_HSIZE_SHIFT);
+}
+
+/*
+ *	socket join an anycast group
+ */
+
+int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct net_device *dev = NULL;
+	struct inet6_dev *idev;
+	struct ipv6_ac_socklist *pac;
+	struct net *net = sock_net(sk);
+	int	ishost = !net->ipv6.devconf_all->forwarding;
+	int	err = 0;
+
+	ASSERT_RTNL();
+
+	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+		return -EPERM;
+	if (ipv6_addr_is_multicast(addr))
+		return -EINVAL;
+
+	if (ifindex)
+		dev = __dev_get_by_index(net, ifindex);
+
+	if (ipv6_chk_addr_and_flags(net, addr, dev, true, 0, IFA_F_TENTATIVE))
+		return -EINVAL;
+
+	pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
+	if (!pac)
+		return -ENOMEM;
+	pac->acl_next = NULL;
+	pac->acl_addr = *addr;
+
+	if (ifindex == 0) {
+		struct rt6_info *rt;
+
+		rt = rt6_lookup(net, addr, NULL, 0, NULL, 0);
+		if (rt) {
+			dev = rt->dst.dev;
+			ip6_rt_put(rt);
+		} else if (ishost) {
+			err = -EADDRNOTAVAIL;
+			goto error;
+		} else {
+			/* router, no matching interface: just pick one */
+			dev = __dev_get_by_flags(net, IFF_UP,
+						 IFF_UP | IFF_LOOPBACK);
+		}
+	}
+
+	if (!dev) {
+		err = -ENODEV;
+		goto error;
+	}
+
+	idev = __in6_dev_get(dev);
+	if (!idev) {
+		if (ifindex)
+			err = -ENODEV;
+		else
+			err = -EADDRNOTAVAIL;
+		goto error;
+	}
+	/* reset ishost, now that we have a specific device */
+	ishost = !idev->cnf.forwarding;
+
+	pac->acl_ifindex = dev->ifindex;
+
+	/* XXX
+	 * For hosts, allow link-local or matching prefix anycasts.
+	 * This obviates the need for propagating anycast routes while
+	 * still allowing some non-router anycast participation.
+	 */
+	if (!ipv6_chk_prefix(addr, dev)) {
+		if (ishost)
+			err = -EADDRNOTAVAIL;
+		if (err)
+			goto error;
+	}
+
+	err = __ipv6_dev_ac_inc(idev, addr);
+	if (!err) {
+		pac->acl_next = np->ipv6_ac_list;
+		np->ipv6_ac_list = pac;
+		pac = NULL;
+	}
+
+error:
+	if (pac)
+		sock_kfree_s(sk, pac, sizeof(*pac));
+	return err;
+}
+
+/*
+ *	socket leave an anycast group
+ */
+int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct net_device *dev;
+	struct ipv6_ac_socklist *pac, *prev_pac;
+	struct net *net = sock_net(sk);
+
+	ASSERT_RTNL();
+
+	prev_pac = NULL;
+	for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
+		if ((ifindex == 0 || pac->acl_ifindex == ifindex) &&
+		     ipv6_addr_equal(&pac->acl_addr, addr))
+			break;
+		prev_pac = pac;
+	}
+	if (!pac)
+		return -ENOENT;
+	if (prev_pac)
+		prev_pac->acl_next = pac->acl_next;
+	else
+		np->ipv6_ac_list = pac->acl_next;
+
+	dev = __dev_get_by_index(net, pac->acl_ifindex);
+	if (dev)
+		ipv6_dev_ac_dec(dev, &pac->acl_addr);
+
+	sock_kfree_s(sk, pac, sizeof(*pac));
+	return 0;
+}
+
+void __ipv6_sock_ac_close(struct sock *sk)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct net_device *dev = NULL;
+	struct ipv6_ac_socklist *pac;
+	struct net *net = sock_net(sk);
+	int	prev_index;
+
+	ASSERT_RTNL();
+	pac = np->ipv6_ac_list;
+	np->ipv6_ac_list = NULL;
+
+	prev_index = 0;
+	while (pac) {
+		struct ipv6_ac_socklist *next = pac->acl_next;
+
+		if (pac->acl_ifindex != prev_index) {
+			dev = __dev_get_by_index(net, pac->acl_ifindex);
+			prev_index = pac->acl_ifindex;
+		}
+		if (dev)
+			ipv6_dev_ac_dec(dev, &pac->acl_addr);
+		sock_kfree_s(sk, pac, sizeof(*pac));
+		pac = next;
+	}
+}
+
+void ipv6_sock_ac_close(struct sock *sk)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+
+	if (!np->ipv6_ac_list)
+		return;
+	rtnl_lock();
+	__ipv6_sock_ac_close(sk);
+	rtnl_unlock();
+}
+
+static void ipv6_add_acaddr_hash(struct net *net, struct ifacaddr6 *aca)
+{
+	unsigned int hash = inet6_acaddr_hash(net, &aca->aca_addr);
+
+	spin_lock(&acaddr_hash_lock);
+	hlist_add_head_rcu(&aca->aca_addr_lst, &inet6_acaddr_lst[hash]);
+	spin_unlock(&acaddr_hash_lock);
+}
+
+static void ipv6_del_acaddr_hash(struct ifacaddr6 *aca)
+{
+	spin_lock(&acaddr_hash_lock);
+	hlist_del_init_rcu(&aca->aca_addr_lst);
+	spin_unlock(&acaddr_hash_lock);
+}
+
+static void aca_get(struct ifacaddr6 *aca)
+{
+	refcount_inc(&aca->aca_refcnt);
+}
+
+static void aca_free_rcu(struct rcu_head *h)
+{
+	struct ifacaddr6 *aca = container_of(h, struct ifacaddr6, rcu);
+
+	fib6_info_release(aca->aca_rt);
+	kfree(aca);
+}
+
+static void aca_put(struct ifacaddr6 *ac)
+{
+	if (refcount_dec_and_test(&ac->aca_refcnt)) {
+		call_rcu(&ac->rcu, aca_free_rcu);
+	}
+}
+
+static struct ifacaddr6 *aca_alloc(struct fib6_info *f6i,
+				   const struct in6_addr *addr)
+{
+	struct ifacaddr6 *aca;
+
+	aca = kzalloc(sizeof(*aca), GFP_ATOMIC);
+	if (!aca)
+		return NULL;
+
+	aca->aca_addr = *addr;
+	fib6_info_hold(f6i);
+	aca->aca_rt = f6i;
+	INIT_HLIST_NODE(&aca->aca_addr_lst);
+	aca->aca_users = 1;
+	/* aca_tstamp should be updated upon changes */
+	aca->aca_cstamp = aca->aca_tstamp = jiffies;
+	refcount_set(&aca->aca_refcnt, 1);
+
+	return aca;
+}
+
+/*
+ *	device anycast group inc (add if not found)
+ */
+int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr)
+{
+	struct ifacaddr6 *aca;
+	struct fib6_info *f6i;
+	struct net *net;
+	int err;
+
+	ASSERT_RTNL();
+
+	write_lock_bh(&idev->lock);
+	if (idev->dead) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
+		if (ipv6_addr_equal(&aca->aca_addr, addr)) {
+			aca->aca_users++;
+			err = 0;
+			goto out;
+		}
+	}
+
+	net = dev_net(idev->dev);
+	f6i = addrconf_f6i_alloc(net, idev, addr, true, GFP_ATOMIC);
+	if (IS_ERR(f6i)) {
+		err = PTR_ERR(f6i);
+		goto out;
+	}
+	aca = aca_alloc(f6i, addr);
+	if (!aca) {
+		fib6_info_release(f6i);
+		err = -ENOMEM;
+		goto out;
+	}
+
+	aca->aca_next = idev->ac_list;
+	idev->ac_list = aca;
+
+	/* Hold this for addrconf_join_solict() below before we unlock,
+	 * it is already exposed via idev->ac_list.
+	 */
+	aca_get(aca);
+	write_unlock_bh(&idev->lock);
+
+	ipv6_add_acaddr_hash(net, aca);
+
+	ip6_ins_rt(net, f6i);
+
+	addrconf_join_solict(idev->dev, &aca->aca_addr);
+
+	aca_put(aca);
+	return 0;
+out:
+	write_unlock_bh(&idev->lock);
+	return err;
+}
+
+/*
+ *	device anycast group decrement
+ */
+int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr)
+{
+	struct ifacaddr6 *aca, *prev_aca;
+
+	ASSERT_RTNL();
+
+	write_lock_bh(&idev->lock);
+	prev_aca = NULL;
+	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
+		if (ipv6_addr_equal(&aca->aca_addr, addr))
+			break;
+		prev_aca = aca;
+	}
+	if (!aca) {
+		write_unlock_bh(&idev->lock);
+		return -ENOENT;
+	}
+	if (--aca->aca_users > 0) {
+		write_unlock_bh(&idev->lock);
+		return 0;
+	}
+	if (prev_aca)
+		prev_aca->aca_next = aca->aca_next;
+	else
+		idev->ac_list = aca->aca_next;
+	write_unlock_bh(&idev->lock);
+	ipv6_del_acaddr_hash(aca);
+	addrconf_leave_solict(idev, &aca->aca_addr);
+
+	ip6_del_rt(dev_net(idev->dev), aca->aca_rt, false);
+
+	aca_put(aca);
+	return 0;
+}
+
+/* called with rtnl_lock() */
+static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr)
+{
+	struct inet6_dev *idev = __in6_dev_get(dev);
+
+	if (!idev)
+		return -ENODEV;
+	return __ipv6_dev_ac_dec(idev, addr);
+}
+
+void ipv6_ac_destroy_dev(struct inet6_dev *idev)
+{
+	struct ifacaddr6 *aca;
+
+	write_lock_bh(&idev->lock);
+	while ((aca = idev->ac_list) != NULL) {
+		idev->ac_list = aca->aca_next;
+		write_unlock_bh(&idev->lock);
+
+		ipv6_del_acaddr_hash(aca);
+
+		addrconf_leave_solict(idev, &aca->aca_addr);
+
+		ip6_del_rt(dev_net(idev->dev), aca->aca_rt, false);
+
+		aca_put(aca);
+
+		write_lock_bh(&idev->lock);
+	}
+	write_unlock_bh(&idev->lock);
+}
+
+/*
+ *	check if the interface has this anycast address
+ *	called with rcu_read_lock()
+ */
+static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr)
+{
+	struct inet6_dev *idev;
+	struct ifacaddr6 *aca;
+
+	idev = __in6_dev_get(dev);
+	if (idev) {
+		read_lock_bh(&idev->lock);
+		for (aca = idev->ac_list; aca; aca = aca->aca_next)
+			if (ipv6_addr_equal(&aca->aca_addr, addr))
+				break;
+		read_unlock_bh(&idev->lock);
+		return aca != NULL;
+	}
+	return false;
+}
+
+/*
+ *	check if given interface (or any, if dev==0) has this anycast address
+ */
+bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev,
+			 const struct in6_addr *addr)
+{
+	struct net_device *nh_dev;
+	struct ifacaddr6 *aca;
+	bool found = false;
+
+	rcu_read_lock();
+	if (dev)
+		found = ipv6_chk_acast_dev(dev, addr);
+	else {
+		unsigned int hash = inet6_acaddr_hash(net, addr);
+
+		hlist_for_each_entry_rcu(aca, &inet6_acaddr_lst[hash],
+					 aca_addr_lst) {
+			nh_dev = fib6_info_nh_dev(aca->aca_rt);
+			if (!nh_dev || !net_eq(dev_net(nh_dev), net))
+				continue;
+			if (ipv6_addr_equal(&aca->aca_addr, addr)) {
+				found = true;
+				break;
+			}
+		}
+	}
+	rcu_read_unlock();
+	return found;
+}
+
+/*	check if this anycast address is link-local on given interface or
+ *	is global
+ */
+bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev,
+			     const struct in6_addr *addr)
+{
+	return ipv6_chk_acast_addr(net,
+				   (ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ?
+				    dev : NULL),
+				   addr);
+}
+
+#ifdef CONFIG_PROC_FS
+struct ac6_iter_state {
+	struct seq_net_private p;
+	struct net_device *dev;
+	struct inet6_dev *idev;
+};
+
+#define ac6_seq_private(seq)	((struct ac6_iter_state *)(seq)->private)
+
+static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
+{
+	struct ifacaddr6 *im = NULL;
+	struct ac6_iter_state *state = ac6_seq_private(seq);
+	struct net *net = seq_file_net(seq);
+
+	state->idev = NULL;
+	for_each_netdev_rcu(net, state->dev) {
+		struct inet6_dev *idev;
+		idev = __in6_dev_get(state->dev);
+		if (!idev)
+			continue;
+		read_lock_bh(&idev->lock);
+		im = idev->ac_list;
+		if (im) {
+			state->idev = idev;
+			break;
+		}
+		read_unlock_bh(&idev->lock);
+	}
+	return im;
+}
+
+static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im)
+{
+	struct ac6_iter_state *state = ac6_seq_private(seq);
+
+	im = im->aca_next;
+	while (!im) {
+		if (likely(state->idev != NULL))
+			read_unlock_bh(&state->idev->lock);
+
+		state->dev = next_net_device_rcu(state->dev);
+		if (!state->dev) {
+			state->idev = NULL;
+			break;
+		}
+		state->idev = __in6_dev_get(state->dev);
+		if (!state->idev)
+			continue;
+		read_lock_bh(&state->idev->lock);
+		im = state->idev->ac_list;
+	}
+	return im;
+}
+
+static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
+{
+	struct ifacaddr6 *im = ac6_get_first(seq);
+	if (im)
+		while (pos && (im = ac6_get_next(seq, im)) != NULL)
+			--pos;
+	return pos ? NULL : im;
+}
+
+static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
+{
+	rcu_read_lock();
+	return ac6_get_idx(seq, *pos);
+}
+
+static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct ifacaddr6 *im = ac6_get_next(seq, v);
+
+	++*pos;
+	return im;
+}
+
+static void ac6_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU)
+{
+	struct ac6_iter_state *state = ac6_seq_private(seq);
+
+	if (likely(state->idev != NULL)) {
+		read_unlock_bh(&state->idev->lock);
+		state->idev = NULL;
+	}
+	rcu_read_unlock();
+}
+
+static int ac6_seq_show(struct seq_file *seq, void *v)
+{
+	struct ifacaddr6 *im = (struct ifacaddr6 *)v;
+	struct ac6_iter_state *state = ac6_seq_private(seq);
+
+	seq_printf(seq, "%-4d %-15s %pi6 %5d\n",
+		   state->dev->ifindex, state->dev->name,
+		   &im->aca_addr, im->aca_users);
+	return 0;
+}
+
+static const struct seq_operations ac6_seq_ops = {
+	.start	=	ac6_seq_start,
+	.next	=	ac6_seq_next,
+	.stop	=	ac6_seq_stop,
+	.show	=	ac6_seq_show,
+};
+
+int __net_init ac6_proc_init(struct net *net)
+{
+	if (!proc_create_net("anycast6", 0444, net->proc_net, &ac6_seq_ops,
+			sizeof(struct ac6_iter_state)))
+		return -ENOMEM;
+
+	return 0;
+}
+
+void ac6_proc_exit(struct net *net)
+{
+	remove_proc_entry("anycast6", net->proc_net);
+}
+#endif
+
+/*	Init / cleanup code
+ */
+int __init ipv6_anycast_init(void)
+{
+	int i;
+
+	for (i = 0; i < IN6_ADDR_HSIZE; i++)
+		INIT_HLIST_HEAD(&inet6_acaddr_lst[i]);
+	return 0;
+}
+
+void ipv6_anycast_cleanup(void)
+{
+	int i;
+
+	spin_lock(&acaddr_hash_lock);
+	for (i = 0; i < IN6_ADDR_HSIZE; i++)
+		WARN_ON(!hlist_empty(&inet6_acaddr_lst[i]));
+	spin_unlock(&acaddr_hash_lock);
+}