/* * Forwarding database * Linux ethernet bridge * * Authors: * Lennert Buytenhek <buytenh@gnu.org> * * 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/kernel.h> #include <linux/init.h> #include <linux/rculist.h> #include <linux/spinlock.h> #include <linux/times.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/jhash.h> #include <linux/random.h> #include <linux/slab.h> #include <linux/atomic.h> #include <asm/unaligned.h> #include "br_private.h" static struct kmem_cache *br_fdb_cache __read_mostly; static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source, const unsigned char *addr); static void fdb_notify(struct net_bridge *br, const struct net_bridge_fdb_entry *, int); static u32 fdb_salt __read_mostly; int __init br_fdb_init(void) { br_fdb_cache = kmem_cache_create("bridge_fdb_cache", sizeof(struct net_bridge_fdb_entry), 0, SLAB_HWCACHE_ALIGN, NULL); if (!br_fdb_cache) return -ENOMEM; get_random_bytes(&fdb_salt, sizeof(fdb_salt)); return 0; } void br_fdb_fini(void) { kmem_cache_destroy(br_fdb_cache); } /* if topology_changing then use forward_delay (default 15 sec) * otherwise keep longer (default 5 minutes) */ static inline unsigned long hold_time(const struct net_bridge *br) { return br->topology_change ? br->forward_delay : br->ageing_time; } static inline int has_expired(const struct net_bridge *br, const struct net_bridge_fdb_entry *fdb) { return !fdb->is_static && time_before_eq(fdb->updated + hold_time(br), jiffies); } static inline int br_mac_hash(const unsigned char *mac) { /* use 1 byte of OUI cnd 3 bytes of NIC */ u32 key = get_unaligned((u32 *)(mac + 2)); return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1); } static void fdb_rcu_free(struct rcu_head *head) { struct net_bridge_fdb_entry *ent = container_of(head, struct net_bridge_fdb_entry, rcu); kmem_cache_free(br_fdb_cache, ent); } static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f) { hlist_del_rcu(&f->hlist); fdb_notify(br, f, RTM_DELNEIGH); call_rcu(&f->rcu, fdb_rcu_free); } void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr) { struct net_bridge *br = p->br; int i; spin_lock_bh(&br->hash_lock); /* Search all chains since old address/hash is unknown */ for (i = 0; i < BR_HASH_SIZE; i++) { struct hlist_node *h; hlist_for_each(h, &br->hash[i]) { struct net_bridge_fdb_entry *f; f = hlist_entry(h, struct net_bridge_fdb_entry, hlist); if (f->dst == p && f->is_local) { /* maybe another port has same hw addr? */ struct net_bridge_port *op; list_for_each_entry(op, &br->port_list, list) { if (op != p && !compare_ether_addr(op->dev->dev_addr, f->addr.addr)) { f->dst = op; goto insert; } } /* delete old one */ fdb_delete(br, f); goto insert; } } } insert: /* insert new address, may fail if invalid address or dup. */ fdb_insert(br, p, newaddr); spin_unlock_bh(&br->hash_lock); } void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr) { struct net_bridge_fdb_entry *f; /* If old entry was unassociated with any port, then delete it. */ f = __br_fdb_get(br, br->dev->dev_addr); if (f && f->is_local && !f->dst) fdb_delete(br, f); fdb_insert(br, NULL, newaddr); } void br_fdb_cleanup(unsigned long _data) { struct net_bridge *br = (struct net_bridge *)_data; unsigned long delay = hold_time(br); unsigned long next_timer = jiffies + br->ageing_time; int i; spin_lock(&br->hash_lock); for (i = 0; i < BR_HASH_SIZE; i++) { struct net_bridge_fdb_entry *f; struct hlist_node *h, *n; hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) { unsigned long this_timer; if (f->is_static) continue; this_timer = f->updated + delay; if (time_before_eq(this_timer, jiffies)) fdb_delete(br, f); else if (time_before(this_timer, next_timer)) next_timer = this_timer; } } spin_unlock(&br->hash_lock); mod_timer(&br->gc_timer, round_jiffies_up(next_timer)); } /* Completely flush all dynamic entries in forwarding database.*/ void br_fdb_flush(struct net_bridge *br) { int i; spin_lock_bh(&br->hash_lock); for (i = 0; i < BR_HASH_SIZE; i++) { struct net_bridge_fdb_entry *f; struct hlist_node *h, *n; hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) { if (!f->is_static) fdb_delete(br, f); } } spin_unlock_bh(&br->hash_lock); } /* Flush all entries referring to a specific port. * if do_all is set also flush static entries */ void br_fdb_delete_by_port(struct net_bridge *br, const struct net_bridge_port *p, int do_all) { int i; spin_lock_bh(&br->hash_lock); for (i = 0; i < BR_HASH_SIZE; i++) { struct hlist_node *h, *g; hlist_for_each_safe(h, g, &br->hash[i]) { struct net_bridge_fdb_entry *f = hlist_entry(h, struct net_bridge_fdb_entry, hlist); if (f->dst != p) continue; if (f->is_static && !do_all) continue; /* * if multiple ports all have the same device address * then when one port is deleted, assign * the local entry to other port */ if (f->is_local) { struct net_bridge_port *op; list_for_each_entry(op, &br->port_list, list) { if (op != p && !compare_ether_addr(op->dev->dev_addr, f->addr.addr)) { f->dst = op; goto skip_delete; } } } fdb_delete(br, f); skip_delete: ; } } spin_unlock_bh(&br->hash_lock); } /* No locking or refcounting, assumes caller has rcu_read_lock */ struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br, const unsigned char *addr) { struct hlist_node *h; struct net_bridge_fdb_entry *fdb; hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) { if (!compare_ether_addr(fdb->addr.addr, addr)) { if (unlikely(has_expired(br, fdb))) break; return fdb; } } return NULL; } #if IS_ENABLED(CONFIG_ATM_LANE) /* Interface used by ATM LANE hook to test * if an addr is on some other bridge port */ int br_fdb_test_addr(struct net_device *dev, unsigned char *addr) { struct net_bridge_fdb_entry *fdb; struct net_bridge_port *port; int ret; rcu_read_lock(); port = br_port_get_rcu(dev); if (!port) ret = 0; else { fdb = __br_fdb_get(port->br, addr); ret = fdb && fdb->dst && fdb->dst->dev != dev && fdb->dst->state == BR_STATE_FORWARDING; } rcu_read_unlock(); return ret; } #endif /* CONFIG_ATM_LANE */ /* * Fill buffer with forwarding table records in * the API format. */ int br_fdb_fillbuf(struct net_bridge *br, void *buf, unsigned long maxnum, unsigned long skip) { struct __fdb_entry *fe = buf; int i, num = 0; struct hlist_node *h; struct net_bridge_fdb_entry *f; memset(buf, 0, maxnum*sizeof(struct __fdb_entry)); rcu_read_lock(); for (i = 0; i < BR_HASH_SIZE; i++) { hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) { if (num >= maxnum) goto out; if (has_expired(br, f)) continue; /* ignore pseudo entry for local MAC address */ if (!f->dst) continue; if (skip) { --skip; continue; } /* convert from internal format to API */ memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN); /* due to ABI compat need to split into hi/lo */ fe->port_no = f->dst->port_no; fe->port_hi = f->dst->port_no >> 8; fe->is_local = f->is_local; if (!f->is_static) fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->updated); ++fe; ++num; } } out: rcu_read_unlock(); return num; } static struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head, const unsigned char *addr) { struct hlist_node *h; struct net_bridge_fdb_entry *fdb; hlist_for_each_entry(fdb, h, head, hlist) { if (!compare_ether_addr(fdb->addr.addr, addr)) return fdb; } return NULL; } static struct net_bridge_fdb_entry *fdb_find_rcu(struct hlist_head *head, const unsigned char *addr) { struct hlist_node *h; struct net_bridge_fdb_entry *fdb; hlist_for_each_entry_rcu(fdb, h, head, hlist) { if (!compare_ether_addr(fdb->addr.addr, addr)) return fdb; } return NULL; } static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head, struct net_bridge_port *source, const unsigned char *addr) { struct net_bridge_fdb_entry *fdb; fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC); if (fdb) { memcpy(fdb->addr.addr, addr, ETH_ALEN); fdb->dst = source; fdb->is_local = 0; fdb->is_static = 0; fdb->updated = fdb->used = jiffies; hlist_add_head_rcu(&fdb->hlist, head); } return fdb; } static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source, const unsigned char *addr) { struct hlist_head *head = &br->hash[br_mac_hash(addr)]; struct net_bridge_fdb_entry *fdb; if (!is_valid_ether_addr(addr)) return -EINVAL; fdb = fdb_find(head, addr); if (fdb) { /* it is okay to have multiple ports with same * address, just use the first one. */ if (fdb->is_local) return 0; br_warn(br, "adding interface %s with same address " "as a received packet\n", source->dev->name); fdb_delete(br, fdb); } fdb = fdb_create(head, source, addr); if (!fdb) return -ENOMEM; fdb->is_local = fdb->is_static = 1; fdb_notify(br, fdb, RTM_NEWNEIGH); return 0; } /* Add entry for local address of interface */ int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source, const unsigned char *addr) { int ret; spin_lock_bh(&br->hash_lock); ret = fdb_insert(br, source, addr); spin_unlock_bh(&br->hash_lock); return ret; } void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, const unsigned char *addr) { struct hlist_head *head = &br->hash[br_mac_hash(addr)]; struct net_bridge_fdb_entry *fdb; /* some users want to always flood. */ if (hold_time(br) == 0) return; /* ignore packets unless we are using this port */ if (!(source->state == BR_STATE_LEARNING || source->state == BR_STATE_FORWARDING)) return; fdb = fdb_find_rcu(head, addr); if (likely(fdb)) { /* attempt to update an entry for a local interface */ if (unlikely(fdb->is_local)) { if (net_ratelimit()) br_warn(br, "received packet on %s with " "own address as source address\n", source->dev->name); } else { /* fastpath: update of existing entry */ fdb->dst = source; fdb->updated = jiffies; } } else { spin_lock(&br->hash_lock); if (likely(!fdb_find(head, addr))) { fdb = fdb_create(head, source, addr); if (fdb) fdb_notify(br, fdb, RTM_NEWNEIGH); } /* else we lose race and someone else inserts * it first, don't bother updating */ spin_unlock(&br->hash_lock); } } static int fdb_to_nud(const struct net_bridge_fdb_entry *fdb) { if (fdb->is_local) return NUD_PERMANENT; else if (fdb->is_static) return NUD_NOARP; else if (has_expired(fdb->dst->br, fdb)) return NUD_STALE; else return NUD_REACHABLE; } static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br, const struct net_bridge_fdb_entry *fdb, u32 pid, u32 seq, int type, unsigned int flags) { unsigned long now = jiffies; struct nda_cacheinfo ci; struct nlmsghdr *nlh; struct ndmsg *ndm; nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags); if (nlh == NULL) return -EMSGSIZE; ndm = nlmsg_data(nlh); ndm->ndm_family = AF_BRIDGE; ndm->ndm_pad1 = 0; ndm->ndm_pad2 = 0; ndm->ndm_flags = 0; ndm->ndm_type = 0; ndm->ndm_ifindex = fdb->dst ? fdb->dst->dev->ifindex : br->dev->ifindex; ndm->ndm_state = fdb_to_nud(fdb); NLA_PUT(skb, NDA_LLADDR, ETH_ALEN, &fdb->addr); ci.ndm_used = jiffies_to_clock_t(now - fdb->used); ci.ndm_confirmed = 0; ci.ndm_updated = jiffies_to_clock_t(now - fdb->updated); ci.ndm_refcnt = 0; NLA_PUT(skb, NDA_CACHEINFO, sizeof(ci), &ci); return nlmsg_end(skb, nlh); nla_put_failure: nlmsg_cancel(skb, nlh); return -EMSGSIZE; } static inline size_t fdb_nlmsg_size(void) { return NLMSG_ALIGN(sizeof(struct ndmsg)) + nla_total_size(ETH_ALEN) /* NDA_LLADDR */ + nla_total_size(sizeof(struct nda_cacheinfo)); } static void fdb_notify(struct net_bridge *br, const struct net_bridge_fdb_entry *fdb, int type) { struct net *net = dev_net(br->dev); struct sk_buff *skb; int err = -ENOBUFS; skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC); if (skb == NULL) goto errout; err = fdb_fill_info(skb, br, fdb, 0, 0, type, 0); if (err < 0) { /* -EMSGSIZE implies BUG in fdb_nlmsg_size() */ WARN_ON(err == -EMSGSIZE); kfree_skb(skb); goto errout; } rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC); return; errout: if (err < 0) rtnl_set_sk_err(net, RTNLGRP_NEIGH, err); } /* Dump information about entries, in response to GETNEIGH */ int br_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb) { struct net *net = sock_net(skb->sk); struct net_device *dev; int idx = 0; rcu_read_lock(); for_each_netdev_rcu(net, dev) { struct net_bridge *br = netdev_priv(dev); int i; if (!(dev->priv_flags & IFF_EBRIDGE)) continue; for (i = 0; i < BR_HASH_SIZE; i++) { struct hlist_node *h; struct net_bridge_fdb_entry *f; hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) { if (idx < cb->args[0]) goto skip; if (fdb_fill_info(skb, br, f, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq, RTM_NEWNEIGH, NLM_F_MULTI) < 0) break; skip: ++idx; } } } rcu_read_unlock(); cb->args[0] = idx; return skb->len; } /* Update (create or replace) forwarding database entry */ static int fdb_add_entry(struct net_bridge_port *source, const __u8 *addr, __u16 state, __u16 flags) { struct net_bridge *br = source->br; struct hlist_head *head = &br->hash[br_mac_hash(addr)]; struct net_bridge_fdb_entry *fdb; fdb = fdb_find(head, addr); if (fdb == NULL) { if (!(flags & NLM_F_CREATE)) return -ENOENT; fdb = fdb_create(head, source, addr); if (!fdb) return -ENOMEM; fdb_notify(br, fdb, RTM_NEWNEIGH); } else { if (flags & NLM_F_EXCL) return -EEXIST; } if (fdb_to_nud(fdb) != state) { if (state & NUD_PERMANENT) fdb->is_local = fdb->is_static = 1; else if (state & NUD_NOARP) { fdb->is_local = 0; fdb->is_static = 1; } else fdb->is_local = fdb->is_static = 0; fdb->updated = fdb->used = jiffies; fdb_notify(br, fdb, RTM_NEWNEIGH); } return 0; } /* Add new permanent fdb entry with RTM_NEWNEIGH */ int br_fdb_add(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg) { struct net *net = sock_net(skb->sk); struct ndmsg *ndm; struct nlattr *tb[NDA_MAX+1]; struct net_device *dev; struct net_bridge_port *p; const __u8 *addr; int err; ASSERT_RTNL(); err = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, NULL); if (err < 0) return err; ndm = nlmsg_data(nlh); if (ndm->ndm_ifindex == 0) { pr_info("bridge: RTM_NEWNEIGH with invalid ifindex\n"); return -EINVAL; } dev = __dev_get_by_index(net, ndm->ndm_ifindex); if (dev == NULL) { pr_info("bridge: RTM_NEWNEIGH with unknown ifindex\n"); return -ENODEV; } if (!tb[NDA_LLADDR] || nla_len(tb[NDA_LLADDR]) != ETH_ALEN) { pr_info("bridge: RTM_NEWNEIGH with invalid address\n"); return -EINVAL; } addr = nla_data(tb[NDA_LLADDR]); if (!is_valid_ether_addr(addr)) { pr_info("bridge: RTM_NEWNEIGH with invalid ether address\n"); return -EINVAL; } if (!(ndm->ndm_state & (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE))) { pr_info("bridge: RTM_NEWNEIGH with invalid state %#x\n", ndm->ndm_state); return -EINVAL; } p = br_port_get_rtnl(dev); if (p == NULL) { pr_info("bridge: RTM_NEWNEIGH %s not a bridge port\n", dev->name); return -EINVAL; } if (ndm->ndm_flags & NTF_USE) { rcu_read_lock(); br_fdb_update(p->br, p, addr); rcu_read_unlock(); } else { spin_lock_bh(&p->br->hash_lock); err = fdb_add_entry(p, addr, ndm->ndm_state, nlh->nlmsg_flags); spin_unlock_bh(&p->br->hash_lock); } return err; } static int fdb_delete_by_addr(struct net_bridge_port *p, const u8 *addr) { struct net_bridge *br = p->br; struct hlist_head *head = &br->hash[br_mac_hash(addr)]; struct net_bridge_fdb_entry *fdb; fdb = fdb_find(head, addr); if (!fdb) return -ENOENT; fdb_delete(p->br, fdb); return 0; } /* Remove neighbor entry with RTM_DELNEIGH */ int br_fdb_delete(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg) { struct net *net = sock_net(skb->sk); struct ndmsg *ndm; struct net_bridge_port *p; struct nlattr *llattr; const __u8 *addr; struct net_device *dev; int err; ASSERT_RTNL(); if (nlmsg_len(nlh) < sizeof(*ndm)) return -EINVAL; ndm = nlmsg_data(nlh); if (ndm->ndm_ifindex == 0) { pr_info("bridge: RTM_DELNEIGH with invalid ifindex\n"); return -EINVAL; } dev = __dev_get_by_index(net, ndm->ndm_ifindex); if (dev == NULL) { pr_info("bridge: RTM_DELNEIGH with unknown ifindex\n"); return -ENODEV; } llattr = nlmsg_find_attr(nlh, sizeof(*ndm), NDA_LLADDR); if (llattr == NULL || nla_len(llattr) != ETH_ALEN) { pr_info("bridge: RTM_DELNEIGH with invalid address\n"); return -EINVAL; } addr = nla_data(llattr); p = br_port_get_rtnl(dev); if (p == NULL) { pr_info("bridge: RTM_DELNEIGH %s not a bridge port\n", dev->name); return -EINVAL; } spin_lock_bh(&p->br->hash_lock); err = fdb_delete_by_addr(p, addr); spin_unlock_bh(&p->br->hash_lock); return err; }