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bridge: range check STP parameters

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Apply restrictions on STP parameters based 802.1D 1998 standard.
   * Fixes missing locking in set path cost ioctl
   * Uses common code for both ioctl and sysfs

This is based on an earlier patch Sasikanth V but with overhaul.

Note:
1. It does NOT enforce the restriction on the relationship max_age and
   forward delay or hello time because in existing implementation these are
   set as independant operations.

2. If STP is disabled, there is no restriction on forward delay

3. No restriction on holding time because users use Linux code to act
   as hub or be sticky.

4. Although standard allow 0-255, Linux only allows 0-63 for port priority
   because more bits are reserved for port number.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger
2011-04-04 14:03:33 +00:00
committed by David S. Miller
parent bb900b27a2
commit 14f98f258f
7 changed files with 107 additions and 93 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
net/bridge/br_stp.c
View File

@@ -484,3 +484,51 @@ void br_received_tcn_bpdu(struct net_bridge_port *p)
br_topology_change_acknowledge(p);
}
}
/* Change bridge STP parameter */
int br_set_hello_time(struct net_bridge *br, unsigned long val)
{
unsigned long t = clock_t_to_jiffies(val);
if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
return -ERANGE;
spin_lock_bh(&br->lock);
br->bridge_hello_time = t;
if (br_is_root_bridge(br))
br->hello_time = br->bridge_hello_time;
spin_unlock_bh(&br->lock);
return 0;
}
int br_set_max_age(struct net_bridge *br, unsigned long val)
{
unsigned long t = clock_t_to_jiffies(val);
if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
return -ERANGE;
spin_lock_bh(&br->lock);
br->bridge_max_age = t;
if (br_is_root_bridge(br))
br->max_age = br->bridge_max_age;
spin_unlock_bh(&br->lock);
return 0;
}
int br_set_forward_delay(struct net_bridge *br, unsigned long val)
{
unsigned long t = clock_t_to_jiffies(val);
if (br->stp_enabled != BR_NO_STP &&
(t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
return -ERANGE;
spin_lock_bh(&br->lock);
br->bridge_forward_delay = t;
if (br_is_root_bridge(br))
br->forward_delay = br->bridge_forward_delay;
spin_unlock_bh(&br->lock);
return 0;
}