v4.19.13 snapshot.
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
new file mode 100644
index 0000000..4e0ff70
--- /dev/null
+++ b/net/ipv6/anycast.c
@@ -0,0 +1,542 @@
+/*
+ * Anycast support for IPv6
+ * Linux INET6 implementation
+ *
+ * Authors:
+ * David L Stevens (dlstevens@us.ibm.com)
+ *
+ * based heavily on net/ipv6/mcast.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#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>
+
+static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr);
+
+/*
+ * 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;
+
+ if (!np->ipv6_ac_list)
+ return;
+
+ rtnl_lock();
+ 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;
+ }
+ rtnl_unlock();
+}
+
+static void aca_get(struct ifacaddr6 *aca)
+{
+ refcount_inc(&aca->aca_refcnt);
+}
+
+static void aca_put(struct ifacaddr6 *ac)
+{
+ if (refcount_dec_and_test(&ac->aca_refcnt)) {
+ fib6_info_release(ac->aca_rt);
+ kfree(ac);
+ }
+}
+
+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;
+ 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);
+
+ 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);
+ addrconf_leave_solict(idev, &aca->aca_addr);
+
+ ip6_del_rt(dev_net(idev->dev), aca->aca_rt);
+
+ 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);
+
+ addrconf_leave_solict(idev, &aca->aca_addr);
+
+ ip6_del_rt(dev_net(idev->dev), aca->aca_rt);
+
+ 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)
+{
+ bool found = false;
+
+ rcu_read_lock();
+ if (dev)
+ found = ipv6_chk_acast_dev(dev, addr);
+ else
+ for_each_netdev_rcu(net, dev)
+ if (ipv6_chk_acast_dev(dev, 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