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| author | Wei Liu <wei.liu2@citrix.com> | 2013-04-22 02:20:41 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-04-22 15:37:01 -0400 |
| commit | 9ecd1a75d977e2e8c48139c7d3efed183f898d94 (patch) | |
| tree | daba39f085896184b65d1724e5441cda6ee213a5 | |
| parent | 697089dc13c52d668322ac6cb8548520de27ed0e (diff) | |
| download | linux-9ecd1a75d977e2e8c48139c7d3efed183f898d94.tar.gz linux-9ecd1a75d977e2e8c48139c7d3efed183f898d94.tar.bz2 linux-9ecd1a75d977e2e8c48139c7d3efed183f898d94.zip | |
xen-netfront: reduce gso_max_size to account for max TCP header
The maximum packet including header that can be handled by netfront / netback
wire format is 65535. Reduce gso_max_size accordingly.
Drop skb and print warning when skb->len > 65535. This can 1) save the effort
to send malformed packet to netback, 2) help spotting misconfiguration of
netfront in the future.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/xen-netfront.c | 17 | ||||
| -rw-r--r-- | include/xen/interface/io/netif.h | 1 |
2 files changed, 16 insertions, 2 deletions
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 1bb2e2072a6a..1db101415069 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -36,7 +36,7 @@ #include <linux/skbuff.h> #include <linux/ethtool.h> #include <linux/if_ether.h> -#include <linux/tcp.h> +#include <net/tcp.h> #include <linux/udp.h> #include <linux/moduleparam.h> #include <linux/mm.h> @@ -547,6 +547,16 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) unsigned int len = skb_headlen(skb); unsigned long flags; + /* If skb->len is too big for wire format, drop skb and alert + * user about misconfiguration. + */ + if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) { + net_alert_ratelimited( + "xennet: skb->len = %u, too big for wire format\n", + skb->len); + goto drop; + } + slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) + xennet_count_skb_frag_slots(skb); if (unlikely(slots > MAX_SKB_FRAGS + 1)) { @@ -1058,7 +1068,8 @@ err: static int xennet_change_mtu(struct net_device *dev, int mtu) { - int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN; + int max = xennet_can_sg(dev) ? + XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER : ETH_DATA_LEN; if (mtu > max) return -EINVAL; @@ -1362,6 +1373,8 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev) SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops); SET_NETDEV_DEV(netdev, &dev->dev); + netif_set_gso_max_size(netdev, XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER); + np->netdev = netdev; netif_carrier_off(netdev); diff --git a/include/xen/interface/io/netif.h b/include/xen/interface/io/netif.h index 9dfc12000980..58fadcac33a1 100644 --- a/include/xen/interface/io/netif.h +++ b/include/xen/interface/io/netif.h @@ -47,6 +47,7 @@ #define _XEN_NETTXF_extra_info (3) #define XEN_NETTXF_extra_info (1U<<_XEN_NETTXF_extra_info) +#define XEN_NETIF_MAX_TX_SIZE 0xFFFF struct xen_netif_tx_request { grant_ref_t gref; /* Reference to buffer page */ uint16_t offset; /* Offset within buffer page */ |