flg_cmp 13 include/uapi/linux/netfilter/xt_tcpudp.h __u8 flg_cmp; /* TCP flags compare byte */ flg_cmp 256 net/netfilter/xt_TCPMSS.c tcpinfo->flg_cmp & TCPHDR_SYN && flg_cmp 105 net/netfilter/xt_tcpudp.c (((unsigned char *)th)[13] & tcpinfo->flg_mask) == tcpinfo->flg_cmp))