taglinefilesource code
tcp152net/inet/ip_fw.cstruct tcphdr    *tcp=(struct tcphdr *)((unsigned long *)ip+ip->ihl);
tcp206net/inet/ip_fw.csrc_port=ntohs(tcp->source);
tcp207net/inet/ip_fw.cdst_port=ntohs(tcp->dest);
tcp208net/inet/ip_fw.cif(tcp->syn && !tcp->ack)