• Petri Gynther's avatar
    net: bcmgenet: fix skb_len in bcmgenet_xmit_single() · 7dd39913
    Petri Gynther authored
    skb_len needs to be skb_headlen(skb) in bcmgenet_xmit_single().
    
    Fragmented skbs can have only Ethernet + IP + TCP headers (14+20+20=54 bytes)
    in the linear buffer, followed by the rest in fragments. Bumping skb_len to
    ETH_ZLEN would be incorrect for this case, as it would introduce garbage
    between TCP header and the fragment data.
    
    This also works with regular/non-fragmented small packets < ETH_ZLEN bytes.
    Successfully tested this on GENETv3 with 42-byte ARP frames.
    
    For testing, I used:
    ethtool -K eth0 tx-checksum-ipv4 off
    ethtool -K eth0 tx-checksum-ipv6 off
    echo 0 > /proc/sys/net/ipv4/tcp_timestamps
    
    Fixes: 1c1008c7 ("net: bcmgenet: add main driver file")
    Signed-off-by: default avatarPetri Gynther <pgynther@google.com>
    Acked-by: default avatarEric Dumazet <edumazet@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    7dd39913
bcmgenet.c 94.8 KB