MPTCP_SUBFLOW_ATTR_SSN_OFFSET
nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_SSN_OFFSET, sf->ssn_offset) ||
if (tb[MPTCP_SUBFLOW_ATTR_SSN_OFFSET])
rta_getattr(__u32, tb[MPTCP_SUBFLOW_ATTR_SSN_OFFSET]));