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linux-next/net/bridge/br_device.c
Simon Wunderlich 4adf0af681 bridge: send correct MTU value in PMTU (revised)
When bridging interfaces with different MTUs, the bridge correctly chooses
the minimum of the MTUs of the physical devices as the bridges MTU.  But
when a frame is passed which fits through the incoming, but not through
the outgoing interface, a "Fragmentation Needed" packet is generated.

However, the propagated MTU is hardcoded to 1500, which is wrong in this
situation.  The sender will repeat the packet again with the same frame
size, and the same problem will occur again.

Instead of sending 1500, the (correct) MTU value of the bridge is now sent
via PMTU.  To achieve this, the corresponding rtable structure is stored
in its net_bridge structure.

Modified to get rid of fake_net_device as well.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-30 16:27:55 -07:00

178 lines
3.9 KiB
C

/*
* Device handling code
* 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/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <asm/uaccess.h>
#include "br_private.h"
/* net device transmit always called with no BH (preempt_disabled) */
int br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
const unsigned char *dest = skb->data;
struct net_bridge_fdb_entry *dst;
dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;
skb_reset_mac_header(skb);
skb_pull(skb, ETH_HLEN);
if (dest[0] & 1)
br_flood_deliver(br, skb);
else if ((dst = __br_fdb_get(br, dest)) != NULL)
br_deliver(dst->dst, skb);
else
br_flood_deliver(br, skb);
return 0;
}
static int br_dev_open(struct net_device *dev)
{
struct net_bridge *br = netdev_priv(dev);
br_features_recompute(br);
netif_start_queue(dev);
br_stp_enable_bridge(br);
return 0;
}
static void br_dev_set_multicast_list(struct net_device *dev)
{
}
static int br_dev_stop(struct net_device *dev)
{
br_stp_disable_bridge(netdev_priv(dev));
netif_stop_queue(dev);
return 0;
}
static int br_change_mtu(struct net_device *dev, int new_mtu)
{
struct net_bridge *br = netdev_priv(dev);
if (new_mtu < 68 || new_mtu > br_min_mtu(br))
return -EINVAL;
dev->mtu = new_mtu;
#ifdef CONFIG_BRIDGE_NETFILTER
/* remember the MTU in the rtable for PMTU */
br->fake_rtable.u.dst.metrics[RTAX_MTU - 1] = new_mtu;
#endif
return 0;
}
/* Allow setting mac address to any valid ethernet address. */
static int br_set_mac_address(struct net_device *dev, void *p)
{
struct net_bridge *br = netdev_priv(dev);
struct sockaddr *addr = p;
if (!is_valid_ether_addr(addr->sa_data))
return -EINVAL;
spin_lock_bh(&br->lock);
memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
br_stp_change_bridge_id(br, addr->sa_data);
br->flags |= BR_SET_MAC_ADDR;
spin_unlock_bh(&br->lock);
return 0;
}
static void br_getinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
strcpy(info->driver, "bridge");
strcpy(info->version, BR_VERSION);
strcpy(info->fw_version, "N/A");
strcpy(info->bus_info, "N/A");
}
static int br_set_sg(struct net_device *dev, u32 data)
{
struct net_bridge *br = netdev_priv(dev);
if (data)
br->feature_mask |= NETIF_F_SG;
else
br->feature_mask &= ~NETIF_F_SG;
br_features_recompute(br);
return 0;
}
static int br_set_tso(struct net_device *dev, u32 data)
{
struct net_bridge *br = netdev_priv(dev);
if (data)
br->feature_mask |= NETIF_F_TSO;
else
br->feature_mask &= ~NETIF_F_TSO;
br_features_recompute(br);
return 0;
}
static int br_set_tx_csum(struct net_device *dev, u32 data)
{
struct net_bridge *br = netdev_priv(dev);
if (data)
br->feature_mask |= NETIF_F_NO_CSUM;
else
br->feature_mask &= ~NETIF_F_ALL_CSUM;
br_features_recompute(br);
return 0;
}
static struct ethtool_ops br_ethtool_ops = {
.get_drvinfo = br_getinfo,
.get_link = ethtool_op_get_link,
.set_sg = br_set_sg,
.set_tx_csum = br_set_tx_csum,
.set_tso = br_set_tso,
};
void br_dev_setup(struct net_device *dev)
{
random_ether_addr(dev->dev_addr);
ether_setup(dev);
dev->do_ioctl = br_dev_ioctl;
dev->hard_start_xmit = br_dev_xmit;
dev->open = br_dev_open;
dev->set_multicast_list = br_dev_set_multicast_list;
dev->change_mtu = br_change_mtu;
dev->destructor = free_netdev;
SET_ETHTOOL_OPS(dev, &br_ethtool_ops);
dev->stop = br_dev_stop;
dev->tx_queue_len = 0;
dev->set_mac_address = br_set_mac_address;
dev->priv_flags = IFF_EBRIDGE;
dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA |
NETIF_F_GSO_MASK | NETIF_F_NO_CSUM | NETIF_F_LLTX;
}