• Xin Long's avatar
    ip6_gre: update mtu properly in ip6gre_err · 5c25f30c
    Xin Long authored
    Now when probessing ICMPV6_PKT_TOOBIG, ip6gre_err only subtracts the
    offset of gre header from mtu info. The expected mtu of gre device
    should also subtract gre header. Otherwise, the next packets still
    can't be sent out.
    
    Jianlin found this issue when using the topo:
      client(ip6gre)<---->(nic1)route(nic2)<----->(ip6gre)server
    
    and reducing nic2's mtu, then both tcp and sctp's performance with
    big size data became 0.
    
    This patch is to fix it by also subtracting grehdr (tun->tun_hlen)
    from mtu info when updating gre device's mtu in ip6gre_err(). It
    also needs to subtract ETH_HLEN if gre dev'type is ARPHRD_ETHER.
    Reported-by: default avatarJianlin Shi <jishi@redhat.com>
    Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    5c25f30c
ip6_gre.c 39 KB