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OpenCloudOS-Kernel/net/bridge/br_fdb.c

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/*
* 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 <linux/if_vlan.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, u16 vid);
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, __u16 vid)
{
/* use 1 byte of OUI and 3 bytes of NIC */
u32 key = get_unaligned((u32 *)(mac + 2));
return jhash_2words(key, vid, 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;
bool no_vlan = (nbp_get_vlan_info(p) == NULL) ? true : false;
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;
u16 vid = f->vlan_id;
list_for_each_entry(op, &br->port_list, list) {
if (op != p &&
ether_addr_equal(op->dev->dev_addr,
f->addr.addr) &&
nbp_vlan_find(op, vid)) {
f->dst = op;
goto insert;
}
}
/* delete old one */
fdb_delete(br, f);
insert:
/* insert new address, may fail if invalid
* address or dup.
*/
fdb_insert(br, p, newaddr, vid);
/* if this port has no vlan information
* configured, we can safely be done at
* this point.
*/
if (no_vlan)
goto done;
}
}
}
done:
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;
struct net_port_vlans *pv;
u16 vid = 0;
/* If old entry was unassociated with any port, then delete it. */
f = __br_fdb_get(br, br->dev->dev_addr, 0);
if (f && f->is_local && !f->dst)
fdb_delete(br, f);
fdb_insert(br, NULL, newaddr, 0);
/* Now remove and add entries for every VLAN configured on the
* bridge. This function runs under RTNL so the bitmap will not
* change from under us.
*/
pv = br_get_vlan_info(br);
if (!pv)
return;
for_each_set_bit_from(vid, pv->vlan_bitmap, VLAN_N_VID) {
f = __br_fdb_get(br, br->dev->dev_addr, vid);
if (f && f->is_local && !f->dst)
fdb_delete(br, f);
fdb_insert(br, NULL, newaddr, vid);
}
}
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 *n;
hlist_for_each_entry_safe(f, 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 *n;
hlist_for_each_entry_safe(f, 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 &&
ether_addr_equal(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,
__u16 vid)
{
struct net_bridge_fdb_entry *fdb;
hlist_for_each_entry_rcu(fdb,
&br->hash[br_mac_hash(addr, vid)], hlist) {
if (ether_addr_equal(fdb->addr.addr, addr) &&
fdb->vlan_id == vid) {
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, 0);
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 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, &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_delta_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,
__u16 vid)
{
struct net_bridge_fdb_entry *fdb;
hlist_for_each_entry(fdb, head, hlist) {
if (ether_addr_equal(fdb->addr.addr, addr) &&
fdb->vlan_id == vid)
return fdb;
}
return NULL;
}
static struct net_bridge_fdb_entry *fdb_find_rcu(struct hlist_head *head,
const unsigned char *addr,
__u16 vid)
{
struct net_bridge_fdb_entry *fdb;
hlist_for_each_entry_rcu(fdb, head, hlist) {
if (ether_addr_equal(fdb->addr.addr, addr) &&
fdb->vlan_id == vid)
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,
__u16 vid)
{
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->vlan_id = vid;
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, u16 vid)
{
struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
struct net_bridge_fdb_entry *fdb;
if (!is_valid_ether_addr(addr))
return -EINVAL;
fdb = fdb_find(head, addr, vid);
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 ? source->dev->name : br->dev->name);
fdb_delete(br, fdb);
}
fdb = fdb_create(head, source, addr, vid);
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, u16 vid)
{
int ret;
spin_lock_bh(&br->hash_lock);
ret = fdb_insert(br, source, addr, vid);
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, u16 vid)
{
struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
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, vid);
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, vid))) {
fdb = fdb_create(head, source, addr, vid);
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 portid, 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, portid, 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);
if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->addr))
goto nla_put_failure;
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;
if (nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
goto nla_put_failure;
if (nla_put(skb, NDA_VLAN, sizeof(u16), &fdb->vlan_id))
goto nla_put_failure;
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(u16)) /* NDA_VLAN */
+ 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_device *dev,
int idx)
{
struct net_bridge *br = netdev_priv(dev);
int i;
if (!(dev->priv_flags & IFF_EBRIDGE))
goto out;
for (i = 0; i < BR_HASH_SIZE; i++) {
struct net_bridge_fdb_entry *f;
hlist_for_each_entry_rcu(f, &br->hash[i], hlist) {
if (idx < cb->args[0])
goto skip;
if (fdb_fill_info(skb, br, f,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
RTM_NEWNEIGH,
NLM_F_MULTI) < 0)
break;
skip:
++idx;
}
}
out:
return idx;
}
/* Update (create or replace) forwarding database entry */
static int fdb_add_entry(struct net_bridge_port *source, const __u8 *addr,
__u16 state, __u16 flags, __u16 vid)
{
struct net_bridge *br = source->br;
struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
struct net_bridge_fdb_entry *fdb;
bool modified = false;
fdb = fdb_find(head, addr, vid);
if (fdb == NULL) {
if (!(flags & NLM_F_CREATE))
return -ENOENT;
fdb = fdb_create(head, source, addr, vid);
if (!fdb)
return -ENOMEM;
modified = true;
} else {
if (flags & NLM_F_EXCL)
return -EEXIST;
if (fdb->dst != source) {
fdb->dst = source;
modified = true;
}
}
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;
modified = true;
}
fdb->used = jiffies;
if (modified) {
fdb->updated = jiffies;
fdb_notify(br, fdb, RTM_NEWNEIGH);
}
return 0;
}
static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge_port *p,
const unsigned char *addr, u16 nlh_flags, u16 vid)
{
int err = 0;
if (ndm->ndm_flags & NTF_USE) {
rcu_read_lock();
br_fdb_update(p->br, p, addr, vid);
rcu_read_unlock();
} else {
spin_lock_bh(&p->br->hash_lock);
err = fdb_add_entry(p, addr, ndm->ndm_state,
nlh_flags, vid);
spin_unlock_bh(&p->br->hash_lock);
}
return err;
}
/* Add new permanent fdb entry with RTM_NEWNEIGH */
int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
struct net_device *dev,
const unsigned char *addr, u16 nlh_flags)
{
struct net_bridge_port *p;
int err = 0;
struct net_port_vlans *pv;
unsigned short vid = VLAN_N_VID;
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;
}
if (tb[NDA_VLAN]) {
if (nla_len(tb[NDA_VLAN]) != sizeof(unsigned short)) {
pr_info("bridge: RTM_NEWNEIGH with invalid vlan\n");
return -EINVAL;
}
vid = nla_get_u16(tb[NDA_VLAN]);
if (vid >= VLAN_N_VID) {
pr_info("bridge: RTM_NEWNEIGH with invalid vlan id %d\n",
vid);
return -EINVAL;
}
}
if (is_zero_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;
}
pv = nbp_get_vlan_info(p);
if (vid != VLAN_N_VID) {
if (!pv || !test_bit(vid, pv->vlan_bitmap)) {
pr_info("bridge: RTM_NEWNEIGH with unconfigured "
"vlan %d on port %s\n", vid, dev->name);
return -EINVAL;
}
/* VID was specified, so use it. */
err = __br_fdb_add(ndm, p, addr, nlh_flags, vid);
} else {
if (!pv || bitmap_empty(pv->vlan_bitmap, VLAN_N_VID)) {
err = __br_fdb_add(ndm, p, addr, nlh_flags, 0);
goto out;
}
/* We have vlans configured on this port and user didn't
* specify a VLAN. To be nice, add/update entry for every
* vlan on this port.
*/
for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID) {
err = __br_fdb_add(ndm, p, addr, nlh_flags, vid);
if (err)
goto out;
}
}
out:
return err;
}
int fdb_delete_by_addr(struct net_bridge *br, const u8 *addr,
u16 vlan)
{
struct hlist_head *head = &br->hash[br_mac_hash(addr, vlan)];
struct net_bridge_fdb_entry *fdb;
fdb = fdb_find(head, addr, vlan);
if (!fdb)
return -ENOENT;
fdb_delete(br, fdb);
return 0;
}
static int __br_fdb_delete(struct net_bridge_port *p,
const unsigned char *addr, u16 vid)
{
int err;
spin_lock_bh(&p->br->hash_lock);
err = fdb_delete_by_addr(p->br, addr, vid);
spin_unlock_bh(&p->br->hash_lock);
return err;
}
/* Remove neighbor entry with RTM_DELNEIGH */
int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
struct net_device *dev,
const unsigned char *addr)
{
struct net_bridge_port *p;
int err;
struct net_port_vlans *pv;
unsigned short vid = VLAN_N_VID;
if (tb[NDA_VLAN]) {
if (nla_len(tb[NDA_VLAN]) != sizeof(unsigned short)) {
pr_info("bridge: RTM_NEWNEIGH with invalid vlan\n");
return -EINVAL;
}
vid = nla_get_u16(tb[NDA_VLAN]);
if (vid >= VLAN_N_VID) {
pr_info("bridge: RTM_NEWNEIGH with invalid vlan id %d\n",
vid);
return -EINVAL;
}
}
p = br_port_get_rtnl(dev);
if (p == NULL) {
pr_info("bridge: RTM_DELNEIGH %s not a bridge port\n",
dev->name);
return -EINVAL;
}
pv = nbp_get_vlan_info(p);
if (vid != VLAN_N_VID) {
if (!pv || !test_bit(vid, pv->vlan_bitmap)) {
pr_info("bridge: RTM_DELNEIGH with unconfigured "
"vlan %d on port %s\n", vid, dev->name);
return -EINVAL;
}
err = __br_fdb_delete(p, addr, vid);
} else {
if (!pv || bitmap_empty(pv->vlan_bitmap, VLAN_N_VID)) {
err = __br_fdb_delete(p, addr, 0);
goto out;
}
/* We have vlans configured on this port and user didn't
* specify a VLAN. To be nice, add/update entry for every
* vlan on this port.
*/
err = -ENOENT;
for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID) {
err &= __br_fdb_delete(p, addr, vid);
}
}
out:
return err;
}
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