/////////////////////////////////////////////////////////////////////////////////////
//			DHCP Protocol
/////////////////////////////////////////////////////////////////////////////////////
#define DHCP_UDP_OVERHEAD	(14 + /* Ethernet header */		\
				 20 + /* IP header */			\
				 8)   /* UDP header */
#define DHCP_SNAME_LEN		64
#define DHCP_FILE_LEN		128
#define DHCP_FIXED_NON_UDP	236
#define DHCP_FIXED_LEN		(DHCP_FIXED_NON_UDP + DHCP_UDP_OVERHEAD)
						/* Everything but options. */
#define DHCP_MTU_MAX		1500
#define DHCP_OPTION_LEN		(DHCP_MTU_MAX - DHCP_FIXED_LEN)

#define BOOTP_MIN_LEN		300
#define DHCP_MIN_LEN            548

typedef struct dhcp_packet {
#define    ETHERNET_HW_TYPE                   1
#define    ETHERNET_HWADDR_LEN                6
#define   DHCP_CLIENT_BROADCAST               0x8000
#define  MAX_DHSERVER_NAME_LEN                64
  	u_int8_t  op;		/* 0: Message opcode/type */
	u_int8_t  htype;	/* 1: Hardware addr type (net/if_types.h) */
	u_int8_t  hlen;		/* 2: Hardware addr length */
	u_int8_t  hops;		/* 3: Number of relay agent hops from client */
	u_int32_t xid;		/* 4: Transaction ID */
	u_int16_t secs;		/* 8: Seconds since client started looking */
	u_int16_t flags;	/* 10: Flag bits */
	//struct in_addr ciaddr;	/* 12: Client IP address (if already in use) */
	//struct in_addr yiaddr;	/* 16: Client IP address */
	//struct in_addr siaddr;	/* 18: IP address of next server to talk to */
	//struct in_addr giaddr;	/* 20: DHCP relay agent IP address */

	unsigned long ciaddr;	/* 12: Client IP address (if already in use) */
	unsigned long yiaddr;	/* 16: Client IP address */
	unsigned long siaddr;	/* 18: IP address of next server to talk to */
	unsigned long giaddr;	/* 20: DHCP relay agent IP address */
	unsigned char chaddr [16];	/* 24: Client hardware address */
	char sname [DHCP_SNAME_LEN];	/* 40: Server name */
	char file [DHCP_FILE_LEN];	/* 104: Boot filename */
	//unsigned char options [DHCP_OPTION_LEN];
				/* 212: Optional parameters
				   (actual length dependent on MTU). */
}dhcp_packet_t;

/* BOOTP (rfc951) message types */
#define	BOOTREQUEST	1
#define BOOTREPLY	2

/* Possible values for flags field... */
#define BOOTP_BROADCAST 0x8000 //32768L

/* Possible values for hardware type (htype) field... */
#define HTYPE_ETHER	1               /* Ethernet 10Mbps              */
#define HTYPE_IEEE802	6               /* IEEE 802.2 Token Ring...	*/
#define HTYPE_FDDI	8		/* FDDI...			*/

/* Magic cookie validating dhcp options field (and bootp vendor
   extensions field). */
#define DHCP_OPTIONS_COOKIE	"\143\202\123\143"

/* DHCP Option codes: */

#define DHO_PAD				0
#define DHO_SUBNET_MASK			1
#define DHO_TIME_OFFSET			2
#define DHO_ROUTERS				3
#define DHO_TIME_SERVERS		4
#define DHO_NAME_SERVERS		5
#define DHO_DOMAIN_NAME_SERVERS	6
#define DHO_LOG_SERVERS			7
#define DHO_COOKIE_SERVERS		8
#define DHO_LPR_SERVERS			9
#define DHO_IMPRESS_SERVERS		10
#define DHO_RESOURCE_LOCATION_SERVERS	11
#define DHO_HOST_NAME			12
#define DHO_BOOT_SIZE			13
#define DHO_MERIT_DUMP			14
#define DHO_DOMAIN_NAME			15
#define DHO_SWAP_SERVER			16
#define DHO_ROOT_PATH			17
#define DHO_EXTENSIONS_PATH		18
#define DHO_IP_FORWARDING		19
#define DHO_NON_LOCAL_SOURCE_ROUTING	20
#define DHO_POLICY_FILTER		21
#define DHO_MAX_DGRAM_REASSEMBLY	22
#define DHO_DEFAULT_IP_TTL		23
#define DHO_PATH_MTU_AGING_TIMEOUT	24
#define DHO_PATH_MTU_PLATEAU_TABLE	25
#define DHO_INTERFACE_MTU		26
#define DHO_ALL_SUBNETS_LOCAL		27
#define DHO_BROADCAST_ADDRESS		28
#define DHO_PERFORM_MASK_DISCOVERY	29
#define DHO_MASK_SUPPLIER		30
#define DHO_ROUTER_DISCOVERY		31
#define DHO_ROUTER_SOLICITATION_ADDRESS	32
#define DHO_STATIC_ROUTES		33
#define DHO_TRAILER_ENCAPSULATION	34
#define DHO_ARP_CACHE_TIMEOUT		35
#define DHO_IEEE802_3_ENCAPSULATION	36
#define DHO_DEFAULT_TCP_TTL		37
#define DHO_TCP_KEEPALIVE_INTERVAL	38
#define DHO_TCP_KEEPALIVE_GARBAGE	39
#define DHO_NIS_DOMAIN			40
#define DHO_NIS_SERVERS			41
#define DHO_NTP_SERVERS			42
#define DHO_VENDOR_ENCAPSULATED_OPTIONS	43
#define DHO_NETBIOS_NAME_SERVERS	44
#define DHO_NETBIOS_DD_SERVER		45
#define DHO_NETBIOS_NODE_TYPE		46
#define DHO_NETBIOS_SCOPE		47
#define DHO_FONT_SERVERS		48
#define DHO_X_DISPLAY_MANAGER		49
#define DHO_DHCP_REQUESTED_ADDRESS	50
#define DHO_DHCP_LEASE_TIME		51
#define DHO_DHCP_OPTION_OVERLOAD	52
#define DHO_DHCP_MESSAGE_TYPE		53
#define DHO_DHCP_SERVER_IDENTIFIER	54
#define DHO_DHCP_PARAMETER_REQUEST_LIST	55
#define DHO_DHCP_MESSAGE		56
#define DHO_DHCP_MAX_MESSAGE_SIZE	57
#define DHO_DHCP_RENEWAL_TIME		58
#define DHO_DHCP_REBINDING_TIME		59
#define DHO_VENDOR_CLASS_IDENTIFIER	60
#define DHO_DHCP_CLIENT_IDENTIFIER	61
#define DHO_NWIP_DOMAIN_NAME		62
#define DHO_NWIP_SUBOPTIONS		63
#define DHO_USER_CLASS			77
#define DHO_FQDN			81
#define DHO_DHCP_AGENT_OPTIONS		82
#define DHO_SUBNET_SELECTION		118 /* RFC3011! */
/* The DHO_AUTHENTICATE option is not a standard yet, so I've
   allocated an option out of the "local" option space for it on a
   temporary basis.  Once an option code number is assigned, I will
   immediately and shamelessly break this, so don't count on it
   continuing to work. */
#define DHO_AUTHENTICATE		210

#define DHO_END				255

/* DHCP message types. */
#define DHCPDISCOVER	1
#define DHCPOFFER	2
#define DHCPREQUEST	3
#define DHCPDECLINE	4
#define DHCPACK		5
#define DHCPNAK		6
#define DHCPRELEASE	7
#define DHCPINFORM	8

/* Relay Agent Information option subtypes: */
#define RAI_CIRCUIT_ID	1
#define RAI_REMOTE_ID	2
#define RAI_AGENT_ID	3

/* FQDN suboptions: */
#define FQDN_NO_CLIENT_UPDATE		1
#define FQDN_SERVER_UPDATE		2
#define FQDN_ENCODED			3
#define FQDN_RCODE1			4
#define FQDN_RCODE2			5
#define FQDN_HOSTNAME			6
#define FQDN_DOMAINNAME			7
#define FQDN_FQDN			8
#define FQDN_SUBOPTION_COUNT		8


#define   TIME_LEN                           4
#define   DHCP_MESSAGE_OPTION_LEN            1
/*opcode*/
#define   SERVER_IDENTIFIER_OPCODE           54
#define   CLIENT_IDENTIFIER_OPCODE           61
#define   DHCP_MESSAGE_TYPE                  53
#define   RENEW_TIMEOUT_OPCODE               58
#define   REBIND_TIMEOUT_OPCODE              59
/*End of Default */

#define    DHCP_CLIENT_PACKET_MAXIMUM_LEN     		1024

#define BOOTP_PORT		67
#define END_OPTION		255