| // 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(const struct net *net, |
| const struct in6_addr *addr) |
| { |
| u32 val = __ipv6_addr_jhash(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_hurry(&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 = rtnl_dereference(idev->ac_list); aca; |
| aca = rtnl_dereference(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, NULL); |
| 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; |
| } |
| |
| /* Hold this for addrconf_join_solict() below before we unlock, |
| * it is already exposed via idev->ac_list. |
| */ |
| aca_get(aca); |
| aca->aca_next = idev->ac_list; |
| rcu_assign_pointer(idev->ac_list, 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 = rtnl_dereference(idev->ac_list); aca; |
| aca = rtnl_dereference(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) |
| rcu_assign_pointer(prev_aca->aca_next, aca->aca_next); |
| else |
| rcu_assign_pointer(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 = rtnl_dereference(idev->ac_list)) != NULL) { |
| rcu_assign_pointer(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) { |
| for (aca = rcu_dereference(idev->ac_list); aca; |
| aca = rcu_dereference(aca->aca_next)) |
| if (ipv6_addr_equal(&aca->aca_addr, addr)) |
| break; |
| 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; |
| }; |
| |
| #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private) |
| |
| static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq) |
| { |
| struct ac6_iter_state *state = ac6_seq_private(seq); |
| struct net *net = seq_file_net(seq); |
| struct ifacaddr6 *im = NULL; |
| |
| for_each_netdev_rcu(net, state->dev) { |
| struct inet6_dev *idev; |
| |
| idev = __in6_dev_get(state->dev); |
| if (!idev) |
| continue; |
| im = rcu_dereference(idev->ac_list); |
| if (im) |
| break; |
| } |
| return im; |
| } |
| |
| static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im) |
| { |
| struct ac6_iter_state *state = ac6_seq_private(seq); |
| struct inet6_dev *idev; |
| |
| im = rcu_dereference(im->aca_next); |
| while (!im) { |
| state->dev = next_net_device_rcu(state->dev); |
| if (!state->dev) |
| break; |
| idev = __in6_dev_get(state->dev); |
| if (!idev) |
| continue; |
| im = rcu_dereference(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) |
| { |
| 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); |
| } |