dp_packet_get_nd_payload(const struct dp_packet *b)
{
    return OVS_LIKELY(dp_packet_l4_size(b) >= ND_MSG_LEN)
        ? (const char *)dp_packet_l4(b) + ND_MSG_LEN : NULL;
}
dp_packet_get_nd_payload(const struct dp_packet *b)
{
    return OVS_LIKELY(dp_packet_l4_size(b) >= ND_MSG_LEN)
        ? (const char *)dp_packet_l4(b) + ND_MSG_LEN : NULL;
}