linux/net/bridge/br_fdb.c
stephen hemminger 64af1bac9b bridge: allow updating existing fdb entries
Need to allow application to update existing fdb entries that already
exist. This makes bridge netlink neighbor API have same flags and
semantics as ip neighbor table.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-10-03 12:17:33 -04:00

705 lines
16 KiB
C

/*
* 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(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 inline void fdb_delete(struct net_bridge_fdb_entry *f)
{
fdb_notify(f, RTM_DELNEIGH);
hlist_del_rcu(&f->hlist);
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(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_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_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) {
unsigned long this_timer;
if (f->is_static)
continue;
this_timer = f->updated + delay;
if (time_before_eq(this_timer, jiffies))
fdb_delete(f);
else if (time_before(this_timer, next_timer))
next_timer = this_timer;
}
}
spin_unlock_bh(&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(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(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 defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
/* 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->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;
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);
fdb_notify(fdb, RTM_NEWNEIGH);
}
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(fdb);
}
fdb = fdb_create(head, source, addr);
if (!fdb)
return -ENOMEM;
fdb->is_local = fdb->is_static = 1;
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_create(head, source, addr);
/* 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_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->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(const struct net_bridge_fdb_entry *fdb, int type)
{
struct net *net = dev_net(fdb->dst->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, 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, 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;
}
/* Create new static fdb 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;
} else {
if (flags & NLM_F_EXCL)
return -EEXIST;
if (flags & NLM_F_REPLACE)
fdb->updated = fdb->used = jiffies;
fdb->is_local = fdb->is_static = 0;
}
if (state & NUD_PERMANENT)
fdb->is_local = fdb->is_static = 1;
else if (state & NUD_NOARP)
fdb->is_static = 1;
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;
}
p = br_port_get_rtnl(dev);
if (p == NULL) {
pr_info("bridge: RTM_NEWNEIGH %s not a bridge port\n",
dev->name);
return -EINVAL;
}
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(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;
}