SK_JUMBO_FRAMELEN
if (len < SK_MIN_FRAMELEN || len > SK_JUMBO_FRAMELEN ||
total_len > SK_JUMBO_FRAMELEN ||
#define SK_JUMBO_MTU (SK_JUMBO_FRAMELEN - ETHER_HDR_LEN - ETHER_CRC_LEN)
#define SK_JRAWLEN (SK_JUMBO_FRAMELEN + ETHER_ALIGN)