/* * 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, struct in6_addr *addr); /* Big ac list lock for all the sockets */ static DEFINE_RWLOCK(ipv6_sk_ac_lock); /* * socket join an anycast group */ int ipv6_sock_ac_join(struct sock *sk, int ifindex, 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; if (!capable(CAP_NET_ADMIN)) return -EPERM; if (ipv6_addr_is_multicast(addr)) return -EINVAL; if (ipv6_chk_addr(net, addr, NULL, 0)) return -EINVAL; pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL); if (pac == NULL) return -ENOMEM; pac->acl_next = NULL; ipv6_addr_copy(&pac->acl_addr, addr); rcu_read_lock(); if (ifindex == 0) { struct rt6_info *rt; rt = rt6_lookup(net, addr, NULL, 0, 0); if (rt) { dev = rt->rt6i_dev; dst_release(&rt->dst); } else if (ishost) { err = -EADDRNOTAVAIL; goto error; } else { /* router, no matching interface: just pick one */ dev = dev_get_by_flags_rcu(net, IFF_UP, IFF_UP | IFF_LOOPBACK); } } else dev = dev_get_by_index_rcu(net, ifindex); if (dev == NULL) { 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(dev, addr); if (!err) { write_lock_bh(&ipv6_sk_ac_lock); pac->acl_next = np->ipv6_ac_list; np->ipv6_ac_list = pac; write_unlock_bh(&ipv6_sk_ac_lock); pac = NULL; } error: rcu_read_unlock(); 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, 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); write_lock_bh(&ipv6_sk_ac_lock); 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) { write_unlock_bh(&ipv6_sk_ac_lock); return -ENOENT; } if (prev_pac) prev_pac->acl_next = pac->acl_next; else np->ipv6_ac_list = pac->acl_next; write_unlock_bh(&ipv6_sk_ac_lock); rcu_read_lock(); dev = dev_get_by_index_rcu(net, pac->acl_ifindex); if (dev) ipv6_dev_ac_dec(dev, &pac->acl_addr); rcu_read_unlock(); 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; write_lock_bh(&ipv6_sk_ac_lock); pac = np->ipv6_ac_list; np->ipv6_ac_list = NULL; write_unlock_bh(&ipv6_sk_ac_lock); prev_index = 0; rcu_read_lock(); while (pac) { struct ipv6_ac_socklist *next = pac->acl_next; if (pac->acl_ifindex != prev_index) { dev = dev_get_by_index_rcu(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; } rcu_read_unlock(); } #if 0 /* The function is not used, which is funny. Apparently, author * supposed to use it to filter out datagrams inside udp/raw but forgot. * * It is OK, anycasts are not special comparing to delivery to unicasts. */ int inet6_ac_check(struct sock *sk, struct in6_addr *addr, int ifindex) { struct ipv6_ac_socklist *pac; struct ipv6_pinfo *np = inet6_sk(sk); int found; found = 0; read_lock(&ipv6_sk_ac_lock); for (pac=np->ipv6_ac_list; pac; pac=pac->acl_next) { if (ifindex && pac->acl_ifindex != ifindex) continue; found = ipv6_addr_equal(&pac->acl_addr, addr); if (found) break; } read_unlock(&ipv6_sk_ac_lock); return found; } #endif static void aca_put(struct ifacaddr6 *ac) { if (atomic_dec_and_test(&ac->aca_refcnt)) { in6_dev_put(ac->aca_idev); dst_release(&ac->aca_rt->dst); kfree(ac); } } /* * device anycast group inc (add if not found) */ int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr) { struct ifacaddr6 *aca; struct inet6_dev *idev; struct rt6_info *rt; int err; idev = in6_dev_get(dev); if (idev == NULL) return -EINVAL; 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; } } /* * not found: create a new one. */ aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC); if (aca == NULL) { err = -ENOMEM; goto out; } rt = addrconf_dst_alloc(idev, addr, 1); if (IS_ERR(rt)) { kfree(aca); err = PTR_ERR(rt); goto out; } ipv6_addr_copy(&aca->aca_addr, addr); aca->aca_idev = idev; aca->aca_rt = rt; aca->aca_users = 1; /* aca_tstamp should be updated upon changes */ aca->aca_cstamp = aca->aca_tstamp = jiffies; atomic_set(&aca->aca_refcnt, 2); spin_lock_init(&aca->aca_lock); aca->aca_next = idev->ac_list; idev->ac_list = aca; write_unlock_bh(&idev->lock); ip6_ins_rt(rt); addrconf_join_solict(dev, &aca->aca_addr); aca_put(aca); return 0; out: write_unlock_bh(&idev->lock); in6_dev_put(idev); return err; } /* * device anycast group decrement */ int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr) { struct ifacaddr6 *aca, *prev_aca; 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); dst_hold(&aca->aca_rt->dst); ip6_del_rt(aca->aca_rt); aca_put(aca); return 0; } /* called with rcu_read_lock() */ static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr) { struct inet6_dev *idev = __in6_dev_get(dev); if (idev == NULL) return -ENODEV; return __ipv6_dev_ac_dec(idev, addr); } /* * check if the interface has this anycast address * called with rcu_read_lock() */ static int ipv6_chk_acast_dev(struct net_device *dev, 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 0; } /* * check if given interface (or any, if dev==0) has this anycast address */ int ipv6_chk_acast_addr(struct net *net, struct net_device *dev, struct in6_addr *addr) { int found = 0; 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 = 1; break; } rcu_read_unlock(); return found; } #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, }; static int ac6_seq_open(struct inode *inode, struct file *file) { return seq_open_net(inode, file, &ac6_seq_ops, sizeof(struct ac6_iter_state)); } static const struct file_operations ac6_seq_fops = { .owner = THIS_MODULE, .open = ac6_seq_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_net, }; int __net_init ac6_proc_init(struct net *net) { if (!proc_net_fops_create(net, "anycast6", S_IRUGO, &ac6_seq_fops)) return -ENOMEM; return 0; } void ac6_proc_exit(struct net *net) { proc_net_remove(net, "anycast6"); } #endif