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bridge: implement BPDU blocking 

This is Linux bridge implementation of STP protection
(Cisco BPDU guard/Juniper BPDU block). BPDU block disables
the bridge port if a STP BPDU packet is received.

Why would you want to do this?
If running Spanning Tree on bridge, hostile devices on the network
may send BPDU and cause network failure. Enabling bpdu block
will detect and stop this.

How to recover the port?
The port will be restarted if link is brought down, or
removed and reattached.  For example:
 # ip li set dev eth0 down; ip li set dev eth0 up

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger 2012-11-13 07:53:07 +00:00 committed by David S. Miller
parent cd7537326e
commit a2e01a65cd
5 changed files with 16 additions and 1 deletions
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1
include/uapi/linux/if_link.h
View File

@ -216,6 +216,7 @@ enum {
IFLA_BRPORT_PRIORITY, /* " priority */
IFLA_BRPORT_COST, /* " cost */
IFLA_BRPORT_MODE, /* mode (hairpin) */
IFLA_BRPORT_GUARD, /* bpdu guard */
__IFLA_BRPORT_MAX
};
#define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)

6
net/bridge/br_netlink.c
View File

@ -26,6 +26,7 @@ static inline size_t br_port_info_size(void)
+ nla_total_size(2) /* IFLA_BRPORT_PRIORITY */
+ nla_total_size(4) /* IFLA_BRPORT_COST */
+ nla_total_size(1) /* IFLA_BRPORT_MODE */
+ nla_total_size(1) /* IFLA_BRPORT_GUARD */
+ 0;
}
@ -49,7 +50,8 @@ static int br_port_fill_attrs(struct sk_buff *skb,
if (nla_put_u8(skb, IFLA_BRPORT_STATE, p->state) ||
nla_put_u16(skb, IFLA_BRPORT_PRIORITY, p->priority) ||
nla_put_u32(skb, IFLA_BRPORT_COST, p->path_cost) ||
nla_put_u8(skb, IFLA_BRPORT_MODE, mode))
nla_put_u8(skb, IFLA_BRPORT_MODE, mode) ||
nla_put_u8(skb, IFLA_BRPORT_GUARD, !!(p->flags & BR_BPDU_GUARD)))
return -EMSGSIZE;
return 0;
@ -162,6 +164,7 @@ static const struct nla_policy ifla_brport_policy[IFLA_BRPORT_MAX + 1] = {
[IFLA_BRPORT_COST] = { .type = NLA_U32 },
[IFLA_BRPORT_PRIORITY] = { .type = NLA_U16 },
[IFLA_BRPORT_MODE] = { .type = NLA_U8 },
[IFLA_BRPORT_GUARD] = { .type = NLA_U8 },
};
/* Change the state of the port and notify spanning tree */
@ -203,6 +206,7 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
int err;
br_set_port_flag(p, tb, IFLA_BRPORT_MODE, BR_HAIRPIN_MODE);
br_set_port_flag(p, tb, IFLA_BRPORT_GUARD, BR_BPDU_GUARD);
if (tb[IFLA_BRPORT_COST]) {
err = br_stp_set_path_cost(p, nla_get_u32(tb[IFLA_BRPORT_COST]));

1
net/bridge/br_private.h
View File

@ -135,6 +135,7 @@ struct net_bridge_port
unsigned long flags;
#define BR_HAIRPIN_MODE 0x00000001
#define BR_BPDU_GUARD 0x00000002
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
u32 multicast_startup_queries_sent;

7
net/bridge/br_stp_bpdu.c
View File

@ -170,6 +170,13 @@ void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
if (!ether_addr_equal(dest, br->group_addr))
goto out;
if (p->flags & BR_BPDU_GUARD) {
br_notice(br, "BPDU received on blocked port %u(%s)\n",
(unsigned int) p->port_no, p->dev->name);
br_stp_disable_port(p);
goto out;
}
buf = skb_pull(skb, 3);
if (buf[0] == BPDU_TYPE_CONFIG) {

2
net/bridge/br_sysfs_if.c
View File

@ -156,6 +156,7 @@ static int store_flush(struct net_bridge_port *p, unsigned long v)
static BRPORT_ATTR(flush, S_IWUSR, NULL, store_flush);
BRPORT_ATTR_FLAG(hairpin_mode, BR_HAIRPIN_MODE);
BRPORT_ATTR_FLAG(bpdu_guard, BR_BPDU_GUARD);
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
@ -189,6 +190,7 @@ static const struct brport_attribute *brport_attrs[] = {
&brport_attr_hold_timer,
&brport_attr_flush,
&brport_attr_hairpin_mode,
&brport_attr_bpdu_guard,
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
&brport_attr_multicast_router,
#endif