TCA_IFE_SMAC
[TCA_IFE_SMAC] = { .len = ETH_ALEN},
if (tb[TCA_IFE_SMAC])
saddr = nla_data(tb[TCA_IFE_SMAC]);
if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, p->eth_src))