net: Disable LRO on devices that are forwarding

Large Receive Offload (LRO) is only appropriate for packets that are
destined for the host, and should be disabled if received packets may be
forwarded.  It can also confuse the GSO on output.

Add dev_disable_lro() function which uses the appropriate ethtool ops to
disable LRO if enabled.

Add calls to dev_disable_lro() in br_add_if() and functions that enable
IPv4 and IPv6 forwarding.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 45dce2b58d4ca41dbcd7ae523d459acff16ae948..1304ad2d71052a7e5d37b34eb9865170fa6cedac 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -886,6 +886,7 @@ extern struct net_device    *__dev_get_by_name(struct net *net, const char *name);
 extern int             dev_alloc_name(struct net_device *dev, const char *name);
 extern int             dev_open(struct net_device *dev);
 extern int             dev_close(struct net_device *dev);
+extern void            dev_disable_lro(struct net_device *dev);
 extern int             dev_queue_xmit(struct sk_buff *skb);
 extern int             register_netdevice(struct net_device *dev);
 extern void            unregister_netdevice(struct net_device *dev);

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 143c954681b82c5f6998f40756ff21bd3a7ea8c0..832a561500d9fe4c5a19008abe8cdcc1a3746037 100644 (file)
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -387,6 +387,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
                goto err2;
 
        rcu_assign_pointer(dev->br_port, p);
+       dev_disable_lro(dev);
        dev_set_promiscuity(dev, 1);
 
        list_add_rcu(&p->list, &br->port_list);

diff --git a/net/core/dev.c b/net/core/dev.c
index a495f712d38ce4683b2a77cde1b55156ac3b619f..f6944ecd5b2ec000e28e6ac5c558706918d05afd 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -90,6 +90,7 @@
 #include <linux/if_ether.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
+#include <linux/ethtool.h>
 #include <linux/notifier.h>
 #include <linux/skbuff.h>
 #include <net/net_namespace.h>
@@ -1123,6 +1124,29 @@ int dev_close(struct net_device *dev)
 }
 
 
+/**
+ *     dev_disable_lro - disable Large Receive Offload on a device
+ *     @dev: device
+ *
+ *     Disable Large Receive Offload (LRO) on a net device.  Must be
+ *     called under RTNL.  This is needed if received packets may be
+ *     forwarded to another interface.
+ */
+void dev_disable_lro(struct net_device *dev)
+{
+       if (dev->ethtool_ops && dev->ethtool_ops->get_flags &&
+           dev->ethtool_ops->set_flags) {
+               u32 flags = dev->ethtool_ops->get_flags(dev);
+               if (flags & ETH_FLAG_LRO) {
+                       flags &= ~ETH_FLAG_LRO;
+                       dev->ethtool_ops->set_flags(dev, flags);
+               }
+       }
+       WARN_ON(dev->features & NETIF_F_LRO);
+}
+EXPORT_SYMBOL(dev_disable_lro);
+
+
 static int dev_boot_phase = 1;
 
 /*

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index f8c0b0aea93a2a218a2abc9decbee8df07998d9f..9de2514946cadf17183ddfc64c984c64368d6964 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -168,6 +168,8 @@ static struct in_device *inetdev_init(struct net_device *dev)
        in_dev->dev = dev;
        if ((in_dev->arp_parms = neigh_parms_alloc(dev, &arp_tbl)) == NULL)
                goto out_kfree;
+       if (IPV4_DEVCONF(in_dev->cnf, FORWARDING))
+               dev_disable_lro(dev);
        /* Reference in_dev->dev */
        dev_hold(dev);
        /* Account for reference dev->ip_ptr (below) */
@@ -1241,6 +1243,8 @@ static void inet_forward_change(struct net *net)
        read_lock(&dev_base_lock);
        for_each_netdev(net, dev) {
                struct in_device *in_dev;
+               if (on)
+                       dev_disable_lro(dev);
                rcu_read_lock();
                in_dev = __in_dev_get_rcu(dev);
                if (in_dev)
@@ -1248,8 +1252,6 @@ static void inet_forward_change(struct net *net)
                rcu_read_unlock();
        }
        read_unlock(&dev_base_lock);
-
-       rt_cache_flush(0);
 }
 
 static int devinet_conf_proc(ctl_table *ctl, int write,
@@ -1335,10 +1337,19 @@ static int devinet_sysctl_forward(ctl_table *ctl, int write,
        if (write && *valp != val) {
                struct net *net = ctl->extra2;
 
-               if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING))
-                       inet_forward_change(net);
-               else if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING))
+               if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
+                       rtnl_lock();
+                       if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) {
+                               inet_forward_change(net);
+                       } else if (*valp) {
+                               struct ipv4_devconf *cnf = ctl->extra1;
+                               struct in_device *idev =
+                                       container_of(cnf, struct in_device, cnf);
+                               dev_disable_lro(idev->dev);
+                       }
+                       rtnl_unlock();
                        rt_cache_flush(0);
+               }
        }
 
        return ret;

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9be6be3a7ff3cecad3fee2a98c904d3af3b9e852..84127d854cfcba1d2007d1149bfa96ef49363e83 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -348,6 +348,8 @@ static struct inet6_dev * ipv6_add_dev(struct net_device *dev)
                kfree(ndev);
                return NULL;
        }
+       if (ndev->cnf.forwarding)
+               dev_disable_lro(dev);
        /* We refer to the device */
        dev_hold(dev);
 
@@ -442,6 +444,8 @@ static void dev_forward_change(struct inet6_dev *idev)
        if (!idev)
                return;
        dev = idev->dev;
+       if (idev->cnf.forwarding)
+               dev_disable_lro(dev);
        if (dev && (dev->flags & IFF_MULTICAST)) {
                if (idev->cnf.forwarding)
                        ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters);
@@ -487,12 +491,14 @@ static void addrconf_fixup_forwarding(struct ctl_table *table, int *p, int old)
        if (p == &net->ipv6.devconf_dflt->forwarding)
                return;
 
+       rtnl_lock();
        if (p == &net->ipv6.devconf_all->forwarding) {
                __s32 newf = net->ipv6.devconf_all->forwarding;
                net->ipv6.devconf_dflt->forwarding = newf;
                addrconf_forward_change(net, newf);
        } else if ((!*p) ^ (!old))
                dev_forward_change((struct inet6_dev *)table->extra1);
+       rtnl_unlock();
 
        if (*p)
                rt6_purge_dflt_routers(net);