#ifndef _IPV4_H
#define _IPV4_H

#include <system.h>

struct ethernet_packet {
	uint8_t destination[6];
	uint8_t source[6];
	uint16_t type;
	uint8_t payload[];
} __attribute__((packed));

struct ipv4_packet {
	uint8_t  version_ihl;
	uint8_t  dscp_ecn;
	uint16_t length;
	uint16_t ident;
	uint16_t flags_fragment;
	uint8_t  ttl;
	uint8_t  protocol;
	uint16_t checksum;
	uint32_t source;
	uint32_t destination;
	uint8_t  payload[];
} __attribute__ ((packed));

struct udp_packet {
	uint16_t source_port;
	uint16_t destination_port;
	uint16_t length;
	uint16_t checksum;
	uint8_t  payload[];
} __attribute__ ((packed));

struct dhcp_packet {
	uint8_t op;
	uint8_t htype;
	uint8_t hlen;
	uint8_t hops;

	uint32_t xid;

	uint16_t secs;
	uint16_t flags;

	uint32_t ciaddr;
	uint32_t yiaddr;
	uint32_t siaddr;
	uint32_t giaddr;

	uint8_t  chaddr[16];

	uint8_t sname[64];
	uint8_t file[128];

	uint32_t magic;

	uint8_t  options[];
} __attribute__ ((packed));

struct dns_packet {
	uint16_t qid;
	uint16_t flags;
	uint16_t questions;
	uint16_t answers;
	uint16_t authorities;
	uint16_t additional;
	uint8_t data[];
} __attribute__ ((packed));

struct tcp_header {
	uint16_t source_port;
	uint16_t destination_port;

	uint32_t seq_number;
	uint32_t ack_number;

	uint16_t flags;
	uint16_t window_size;
	uint16_t checksum;
	uint16_t urgent;

	uint8_t  payload[];
} __attribute__((packed));

struct tcp_check_header {
	uint32_t source;
	uint32_t destination;
	uint8_t  zeros;
	uint8_t  protocol;
	uint16_t tcp_len;
	uint8_t  tcp_header[];
};


#define htonl(l)  ( (((l) & 0xFF) << 24) | (((l) & 0xFF00) << 8) | (((l) & 0xFF0000) >> 8) | (((l) & 0xFF000000) >> 24))
#define htons(s)  ( (((s) & 0xFF) << 8) | (((s) & 0xFF00) >> 8) )
#define ntohl(l)  htonl((l))
#define ntohs(s)  htons((s))

#define BROADCAST_MAC {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}
#define IPV4_PROT_UDP 17
#define IPV4_PROT_TCP 6
#define DHCP_MAGIC 0x63825363

#define TCP_FLAGS_SYN (1 << 1)
#define TCP_FLAGS_ACK (1 << 4)
#define DATA_OFFSET_5 (0x5 << 12)

extern uint32_t ip_aton(const char * in);
extern void ip_ntoa(uint32_t src_addr, char * out);
extern uint16_t calculate_ipv4_checksum(struct ipv4_packet * p);
uint16_t calculate_tcp_checksum(struct tcp_check_header * p, struct tcp_header * h, void * d, size_t d_words);

struct tcp_socket {
	uint32_t ip;
	uint8_t  mac[6];
	uint32_t port_dest;
	uint32_t port_recv;
	uint32_t seq_no;
	uint32_t ack_no;

	int status;
};

struct sized_blob {
	size_t  size;
	uint8_t blob[];
};

#endif