#ifndef _IP_SET_GETPORT_H
#define _IP_SET_GETPORT_H

#ifdef __KERNEL__
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/ip.h>

#define IPSET_INVALID_PORT	65536

/* We must handle non-linear skbs */

static inline bool
get_port(const struct sk_buff *skb, int protocol, unsigned int protooff,
	 bool src, u16 *port, u8 *proto)
{
	switch (protocol) {
	case IPPROTO_TCP: {
		struct tcphdr _tcph;
		const struct tcphdr *th;
		
		th = skb_header_pointer(skb, protooff, sizeof(_tcph), &_tcph);
		if (th == NULL)
			/* No choice either */
			return false;
	     	
	     	*port = src ? th->source : th->dest;
	     	break;
	}
	case IPPROTO_UDP: {
		struct udphdr _udph;
		const struct udphdr *uh;

		uh = skb_header_pointer(skb, protooff, sizeof(_udph), &_udph);
		if (uh == NULL)
			/* No choice either */
			return false;
	     	
	     	*port = src ? uh->source : uh->dest;
	     	break;
	}
	default:
		if (*proto == IPSET_IPPROTO_TCPUDP)
			return false;
		break;
	}
	if (*proto != IPSET_IPPROTO_TCPUDP)
		*proto = protocol;

	return true;
}

static inline bool
get_ip4_port(const struct sk_buff *skb, bool src, u16 *port, u8 *proto)
{
	const struct iphdr *iph = ip_hdr(skb);
	unsigned int protooff = ip_hdrlen(skb);
	int protocol = iph->protocol;

	if (!(*proto >= IPSET_IPPROTO_TCPUDP || *proto == protocol))
		return false;

	/* See comments at tcp_match in ip_tables.c */
	if (ntohs(iph->frag_off) & IP_OFFSET)
		return false;

	return get_port(skb, protocol, protooff, src, port, proto);
}

static inline bool
get_ip6_port(const struct sk_buff *skb, bool src, u16 *port, u8 *proto)
{
	unsigned int *protooff = 0;
	int protocol;
	unsigned short fragoff;

	protocol = ipv6_find_hdr(skb, protooff, -1, &fragoff);
	if (protocol < 0 || fragoff)
		return false;

	if (!(*proto >= IPSET_IPPROTO_TCPUDP || *proto == protocol))
		return false;

	return get_port(skb, protocol, *protooff, src, port, proto);
}

static inline bool
get_ip_port(const struct sk_buff *skb, u8 pf, bool src, u16 *port)
{
	u8 proto = IPSET_IPPROTO_TCPUDP;

	if (pf == AF_INET)
		return get_ip4_port(skb, src, port, &proto);
	else
		return get_ip6_port(skb, src, port, &proto);
}
#endif /* __KERNEL__ */

#endif /*_IP_SET_GETPORT_H*/