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Message-Id: <20110419161310.7508513909@rere.qmqm.pl>
Date: Tue, 19 Apr 2011 18:13:10 +0200 (CEST)
From: Michał Mirosław <mirq-linux@...e.qmqm.pl>
To: netdev@...r.kernel.org
Cc: Rusty Russell <rusty@...tcorp.com.au>
Subject: [PATCH] net: tun: convert to hw_features
This changes offload setting behaviour to what I think is correct:
- offloads set via ethtool mean what admin wants to use (by default
he wants 'em all)
- offloads set via ioctl() mean what userspace is expecting to get
(this limits which admin wishes are granted)
- TUN_NOCHECKSUM is ignored, as it might cause broken packets when
forwarded (ip_summed == CHECKSUM_UNNECESSARY means that checksum
was verified, not that it can be ignored)
If TUN_NOCHECKSUM is implemented, it should set skb->csum_* and
skb->ip_summed (= CHECKSUM_PARTIAL) for known protocols and let others
be verified by kernel when necessary.
TUN_NOCHECKSUM handling was introduced by commit
f43798c27684ab925adde7d8acc34c78c6e50df8:
tun: Allow GSO using virtio_net_hdr
Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
drivers/net/tun.c | 63 +++++++++++++++++++++--------------------------------
1 files changed, 25 insertions(+), 38 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index f5e9ac0..ade3cf9 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -123,6 +123,9 @@ struct tun_struct {
gid_t group;
struct net_device *dev;
+ u32 set_features;
+#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
+ NETIF_F_TSO6|NETIF_F_UFO)
struct fasync_struct *fasync;
struct tap_filter txflt;
@@ -451,12 +454,20 @@ tun_net_change_mtu(struct net_device *dev, int new_mtu)
return 0;
}
+static u32 tun_net_fix_features(struct net_device *dev, u32 features)
+{
+ struct tun_struct *tun = netdev_priv(dev);
+
+ return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
+}
+
static const struct net_device_ops tun_netdev_ops = {
.ndo_uninit = tun_net_uninit,
.ndo_open = tun_net_open,
.ndo_stop = tun_net_close,
.ndo_start_xmit = tun_net_xmit,
.ndo_change_mtu = tun_net_change_mtu,
+ .ndo_fix_features = tun_net_fix_features,
};
static const struct net_device_ops tap_netdev_ops = {
@@ -465,6 +476,7 @@ static const struct net_device_ops tap_netdev_ops = {
.ndo_stop = tun_net_close,
.ndo_start_xmit = tun_net_xmit,
.ndo_change_mtu = tun_net_change_mtu,
+ .ndo_fix_features = tun_net_fix_features,
.ndo_set_multicast_list = tun_net_mclist,
.ndo_set_mac_address = eth_mac_addr,
.ndo_validate_addr = eth_validate_addr,
@@ -628,8 +640,7 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
kfree_skb(skb);
return -EINVAL;
}
- } else if (tun->flags & TUN_NOCHECKSUM)
- skb->ip_summed = CHECKSUM_UNNECESSARY;
+ }
switch (tun->flags & TUN_TYPE_MASK) {
case TUN_TUN_DEV:
@@ -1094,6 +1105,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
goto err_free_sk;
}
+ dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
+ TUN_USER_FEATURES;
+ dev->features = dev->hw_features;
+
err = register_netdevice(tun->dev);
if (err < 0)
goto err_free_sk;
@@ -1158,18 +1173,12 @@ static int tun_get_iff(struct net *net, struct tun_struct *tun,
/* This is like a cut-down ethtool ops, except done via tun fd so no
* privs required. */
-static int set_offload(struct net_device *dev, unsigned long arg)
+static int set_offload(struct tun_struct *tun, unsigned long arg)
{
- u32 old_features, features;
-
- old_features = dev->features;
- /* Unset features, set them as we chew on the arg. */
- features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
- |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6
- |NETIF_F_UFO));
+ u32 features = 0;
if (arg & TUN_F_CSUM) {
- features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
+ features |= NETIF_F_HW_CSUM;
arg &= ~TUN_F_CSUM;
if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
@@ -1195,9 +1204,8 @@ static int set_offload(struct net_device *dev, unsigned long arg)
if (arg)
return -EINVAL;
- dev->features = features;
- if (old_features != dev->features)
- netdev_features_change(dev);
+ tun->set_features = features;
+ netdev_update_features(tun->dev);
return 0;
}
@@ -1262,12 +1270,9 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
case TUNSETNOCSUM:
/* Disable/Enable checksum */
- if (arg)
- tun->flags |= TUN_NOCHECKSUM;
- else
- tun->flags &= ~TUN_NOCHECKSUM;
- tun_debug(KERN_INFO, tun, "checksum %s\n",
+ /* [unimplemented] */
+ tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
arg ? "disabled" : "enabled");
break;
@@ -1316,7 +1321,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
break;
#endif
case TUNSETOFFLOAD:
- ret = set_offload(tun->dev, arg);
+ ret = set_offload(tun, arg);
break;
case TUNSETTXFILTER:
@@ -1595,30 +1600,12 @@ static void tun_set_msglevel(struct net_device *dev, u32 value)
#endif
}
-static u32 tun_get_rx_csum(struct net_device *dev)
-{
- struct tun_struct *tun = netdev_priv(dev);
- return (tun->flags & TUN_NOCHECKSUM) == 0;
-}
-
-static int tun_set_rx_csum(struct net_device *dev, u32 data)
-{
- struct tun_struct *tun = netdev_priv(dev);
- if (data)
- tun->flags &= ~TUN_NOCHECKSUM;
- else
- tun->flags |= TUN_NOCHECKSUM;
- return 0;
-}
-
static const struct ethtool_ops tun_ethtool_ops = {
.get_settings = tun_get_settings,
.get_drvinfo = tun_get_drvinfo,
.get_msglevel = tun_get_msglevel,
.set_msglevel = tun_set_msglevel,
.get_link = ethtool_op_get_link,
- .get_rx_csum = tun_get_rx_csum,
- .set_rx_csum = tun_set_rx_csum
};
--
1.7.2.5
--
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