tg3: Drop non-VLAN rx pkts larger than the MTU

The hardware's MTU is configured so that it will accept packets whose
VLAN tag is left inline.  This means that the hardware will also accept
other packets larger than the desired MTU size.  This patch checks for
and discards packets that are larger than the requested MTU but are not
VLAN tagged frames.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index c7bbbb19f0006f22385f66f2d162dc7d737ad50f..774a01ab03be9cef6bddda4d39e3b705b28bb7f8 100644 (file)
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -4339,6 +4339,13 @@ static int tg3_rx(struct tg3 *tp, int budget)
                        skb->ip_summed = CHECKSUM_NONE;
 
                skb->protocol = eth_type_trans(skb, tp->dev);
+
+               if (len > (tp->dev->mtu + ETH_HLEN) &&
+                   skb->protocol != htons(ETH_P_8021Q)) {
+                       dev_kfree_skb(skb);
+                       goto next_pkt;
+               }
+
 #if TG3_VLAN_TAG_USED
                if (tp->vlgrp != NULL &&
                    desc->type_flags & RXD_FLAG_VLAN) {
@@ -6824,7 +6831,8 @@ static int tg3_reset_hw(struct tg3 *tp, int reset_phy)
        __tg3_set_mac_addr(tp, 0);
 
        /* MTU + ethernet header + FCS + optional VLAN tag */
-       tw32(MAC_RX_MTU_SIZE, tp->dev->mtu + ETH_HLEN + 8);
+       tw32(MAC_RX_MTU_SIZE,
+            tp->dev->mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN);
 
        /* The slot time is changed by tg3_setup_phy if we
         * run at gigabit with half duplex.