#define MAX_DATA 1024

enum dhcpfieldtype {string, ip, multi, offset, time, number, opt_switch, node_type, bin};

/* 
 * string = \0 terminated char[]
 * ip = 4 byte IP Address
 * multi = vendor defined data with multiple entry pairs (length, data)+
 * time = 4 byte unsinged int in seconds
 * offset = 32-bit int, positive means east of the meridian, negative west
 * number = unsigned int
 * opt_switch = 0/1 switch
 * node_type = 0x1           B-node
 *             0x2           P-node
 *             0x4           M-node
 *             0x8           H-node
 * bin = don't interpret at all - char
 */

struct dhcpoption {
    char name[50];
    enum dhcpfieldtype type;
    unsigned char min_len;
    unsigned char max_len;
} DHCPOPT [256];

DHCPOPT[0] = {"Subnet Mask", ip, 4, 4};
DHCPOPT[1] = {"Time Offset", offset, 4, 4};
DHCPOPT[2] = {"Router Option", ip, 4, 0};
DHCPOPT[3] = {"Time Server Option", ip, 4, 0};
DHCPOPT[4] = {"Name Server Option", ip, 4, 0};
DHCPOPT[5] = {"Domain Name Server Option", ip, 4, 0};
DHCPOPT[6] = {"Log Server Option", ip, 4, 0};
DHCPOPT[7] = {"Cookie Server Option", ip, 4, 0};
DHCPOPT[8] = {"LPR Server Option", ip, 4, 0};
DHCPOPT[9] = {"Impress Server Option", ip, 4, 0};
DHCPOPT[10] = {"Resource Location Server Option", ip, 4, 0};
DHCPOPT[11] = {"Host Name Option", string, 1, 0};
DHCPOPT[12] = {"Boot File Size Option", number, 2, 2}; // unsigned 16-bit integer
DHCPOPT[13] = {"Merit Dump File", string, 1, 0};
DHCPOPT[14] = {"Domain Name", string, 1, 0};
DHCPOPT[15] = {"Swap Server", ip, 4, 4};
DHCPOPT[16] = {"Root Path", string, 1, 0};
DHCPOPT[17] = {"Extensions Path", string, 1, 0};
DHCPOPT[18] = {"IP Forwarding Enable/Disable Option", opt_switch, 1, 1};
DHCPOPT[19] = {"Non-Local Source Routing Enable/Disable Option", opt_switch, 1, 1};
DHCPOPT[20] = {"Policy Filter Option", ip, 8, 0};
DHCPOPT[21] = {"Maximum Datagram Reassembly Size", number, 2, 2};
DHCPOPT[22] = {"Default IP Time-to-live", number, 1, 1};
DHCPOPT[23] = {"Path MTU Aging Timeout Option", time, 4, 4};
DHCPOPT[24] = {"Path MTU Plateau Table Option", number, 2, 0}; // minimum mtu 68
DHCPOPT[25] = {"Interface MTU Option", number, 2, 2};
DHCPOPT[26] = {"All Subnets are Local Option", opt_switch, 1, 1};
DHCPOPT[27] = {"Broadcast Address Option", ip, 4, 4};
DHCPOPT[28] = {"Perform Mask Discovery Option", opt_switch, 1, 1};
DHCPOPT[29] = {"Mask Supplier Option", opt_switch, 1, 1};
DHCPOPT[30] = {"Perform Router Discovery Option", opt_switch, 1, 1};
DHCPOPT[31] = {"Router Solicitation Address Option", ip, 4, 4};
DHCPOPT[32] = {"Static Route Option", ip, 8, 0}; // Default Route 0.0.0.0 is illegal here
DHCPOPT[33] = {"Trailer Encapsulation Option", opt_switch, 1, 1};
DHCPOPT[34] = {"ARP Cache Timeout Option", time, 4, 4};
DHCPOPT[35] = {"Ethernet Encapsulation Option", opt_switch, 1, 1};
DHCPOPT[36] = {"TCP Default TTL Option", number, 1, 1};
DHCPOPT[37] = {"TCP Keepalive Interval Option", time, 4, 4};
DHCPOPT[38] = {"TCP Keepalive Garbage Option", opt_switch, 1, 1};
DHCPOPT[39] = {"Network Information Service Domain Option", string, 1, 0};
DHCPOPT[40] = {"Network Information Servers Option", ip, 4, 0};
DHCPOPT[41] = {"Network Time Protocol Servers Option", ip, 4, 0};
DHCPOPT[42] = {"Vendor Specific Information", multi, 0, 0};
DHCPOPT[43] = {"NetBIOS over TCP/IP Name Server Option", ip, 4, 0};
DHCPOPT[44] = {"NetBIOS over TCP/IP Datagram Distribution Server Option", ip, 4, 0};
DHCPOPT[45] = {"NetBIOS over TCP/IP Node Type Option", node_type, 1, 1};
DHCPOPT[46] = {"NetBIOS over TCP/IP Scope Option", string, 1, 0};
DHCPOPT[47] = {"X Window System Font Server Option", ip, 4, 0};
DHCPOPT[48] = {"X Window System Display Manager Option", ip, 4, 0};
DHCPOPT[49] = {"Requested IP Address", ip, 4, 4};
DHCPOPT[50] = {"IP Address Lease Time", time, 4, 4};
DHCPOPT[51] = {"Option Overload", opt_switch, 1, 1}; // values: 1,2,3
DHCPOPT[52] = {"DHCP Message Type", opt_switch, 1, 1}; // values: 1-8
DHCPOPT[53] = {"Server Identifier", ip, 4, 4};
DHCPOPT[54] = {"Parameter Request List", number, 1, 0};
DHCPOPT[55] = {"Message", string, 1, 0};
DHCPOPT[56] = {"Maximum DHCP Message Size", number, 2, 2};
DHCPOPT[57] = {"Renewal (T1) Time Value", time, 4, 4};
DHCPOPT[58] = {"Rebinding (T2) Time Value", time, 4, 4};
DHCPOPT[59] = {"Vendor class identifier", bin, 1, 0};
DHCPOPT[60] = {"Client-identifier", bin, 2, 0}; // first field: type then data
DHCPOPT[63] = {"Network Information Service+ Domain Option", string, 1, 0};
DHCPOPT[65] = {"TFTP server name", string, 1, 0};
DHCPOPT[66] = {"Bootfile name", string, 1, 0};
DHCPOPT[67] = {"Mobile IP Home Agent option", ip, 4, 0};
DHCPOPT[68] = {"Simple Mail Transport Protocol (SMTP) Server Option", ip, 4, 0};
DHCPOPT[69] = {"Post Office Protocol (POP3) Server Option", ip, 4, 0};
DHCPOPT[70] = {"Network News Transport Protocol (NNTP) Server Option", ip, 4, 0};
DHCPOPT[71] = {"Default World Wide Web (WWW) Server Option", ip, 4, 0};
DHCPOPT[72] = {"Default Finger Server Option", ip, 4, 0};
DHCPOPT[73] = {"Default Internet Relay Chat (IRC) Server Option", ip, 4, 0};
DHCPOPT[74] = {"StreetTalk Server Option", ip, 4, 0};
DHCPOPT[75] = {"StreetTalk Directory Assistance (STDA) Server Option", ip, 4, 0};