tag	line	file	source code
tcp	180	net/ipv4/ip_fw.c	struct tcphdr    *tcp=(struct tcphdr *)((unsigned long *)ip+ip->ihl);
tcp	234	net/ipv4/ip_fw.c	src_port=ntohs(tcp->source);
tcp	235	net/ipv4/ip_fw.c	dst_port=ntohs(tcp->dest);
tcp	236	net/ipv4/ip_fw.c	if(tcp->syn && !tcp->ack)