/* pxe.c - Pre-execution Boot Environment */

#include 

/*------------------------------------------------------------------------
 * get_sysid_entry_point - Retrieve the system ID entry point table address
 *                           from BIOS space.  This is located somewhere
 *                           between SYSID_ENTRY_POINT_SADDR and
 *                           SYSID_ENTRY_POINT_EADDR
 *------------------------------------------------------------------------
 */
struct sysid_entry_point* get_sysid_entry_point()
{
        /* Search for the SYSID Entry Point Table */
        /*   The table is 16 byte aligned and is located somewhere between */
        /*     the starting address and the ending address                 */
        uint32 i;
        for(i = SYSID_ENTRY_POINT_SADDR; i < SYSID_ENTRY_POINT_EADDR; i += 16) {
            struct sysid_entry_point* sysid_entry = (struct sysid_entry_point*)i;
                if(memcmp(sysid_entry->header, SYSID_ENTRY_POINT_HDR, sizeof(sysid_entry->header)) == 0) {
                        return (struct sysid_entry_point*)i;
                }
        }
        return NULL;
}

/*------------------------------------------------------------------------
 * get_uuid - Retrieve the UUID from the system ID table in BIOS
 *------------------------------------------------------------------------
 */
char* get_uuid(uint16* uuid_len)
{
        uint16 i;
        struct sysid_bios_struct* sysid_bios_entry;
        struct sysid_entry_point* sysid_entry = get_sysid_entry_point();
        if(NULL == sysid_entry) {
                (*uuid_len) = 0;
                return NULL;
        }
        
        sysid_bios_entry = (struct sysid_bios_struct*)sysid_entry->bios_structure_addr;
        for(i = 0; i < sysid_entry->bios_struct_count; i++)
        {
                if(memcmp(sysid_bios_entry->header, SYSID_ENTRY_UUID_HDR, sizeof(sysid_bios_entry->header)) == 0) {
                        (*uuid_len) = sysid_bios_entry->len - sizeof(struct sysid_bios_struct);
                        return (char*)(sysid_bios_entry+1);
                }
                
                sysid_bios_entry = (struct sysid_bios_struct*)(((char*)sysid_bios_entry) + sysid_bios_entry->len);
        }
        
        (*uuid_len) = 0;
        return NULL;
}

/*------------------------------------------------------------------------
 * build_dhcp_discover_pxe - handcraft a DHCP Discover message in dmsg
 *------------------------------------------------------------------------
 */
int32 build_dhcp_discover_pxe(struct dhcpmsg* dmsg)
{
        uint32  i,j;
        uint32  xid;                    /* Xid used for the exchange    */
                
        memcpy(&xid, NetData.ethucast, 4);/* Use 4 bytes from MAC as XID */
        memset(dmsg, 0x00, sizeof(struct dhcpmsg));
        
        dmsg->dc_bop = 0x01;            /* Outgoing request             */
        dmsg->dc_htype = 0x01;          /* Hardware type is Ethernet    */
        dmsg->dc_hlen = 0x06;           /* Hardware address length      */
        dmsg->dc_hops = 0x00;           /* Hop count                    */
        dmsg->dc_xid = htonl(xid);      /* Xid (unique ID)              */
        dmsg->dc_secs = 0x0000;         /* Seconds                      */
        dmsg->dc_flags = 0x0000;        /* Flags                        */
        dmsg->dc_cip = 0x00000000;      /* Client IP address            */
        dmsg->dc_yip = 0x00000000;      /* Your IP address              */
        dmsg->dc_sip = 0x00000000;      /* Server IP address            */
        dmsg->dc_gip = 0x00000000;      /* Gateway IP address           */
        memset(&dmsg->dc_chaddr,'\0',16);/* Client hardware address     */
        memcpy(&dmsg->dc_chaddr, NetData.ethucast, ETH_ADDR_LEN);
        memset(&dmsg->dc_bootp,'\0',192);/* zero the bootp area         */
        dmsg->dc_cookie = htonl(0x63825363); /* Magic cookie for DHCP   */
        
        j = 0;
        
        uint16 uuid_len = 0;
        char* uuid = get_uuid(&uuid_len);
        if(uuid_len == 0) {
                kprintf("build_dhcp_discover_pxe: Unable to retrieve UUID\r\n");
                return SYSERR;
        }
        
        dmsg->dc_opt[j++] = 0xff & 97;  /* Client UUID/GUID Type */
        dmsg->dc_opt[j++] = 0xff & (uuid_len + 1);  /* Option length    */
        dmsg->dc_opt[j++] = 0xff &  0;  /* UUID                  */
        for(i = 0; i < uuid_len; i++) {
                dmsg->dc_opt[j++] = 0xff & uuid[i];
        }
        dmsg->dc_opt[j++] = 0xff & 94;  /* Client network type   */
        dmsg->dc_opt[j++] = 0xff &  3;  /* Option length         */
        dmsg->dc_opt[j++] = 0xff &  1;  /* Type = UNDI           */
        dmsg->dc_opt[j++] = 0xff &  1;  /* UNDI Major ver        */
        dmsg->dc_opt[j++] = 0xff &  2;  /* UNDI Minor ver        */
        
        dmsg->dc_opt[j++] = 0xff & 93;  /* Client architecture   */
        dmsg->dc_opt[j++] = 0xff &  2;  /* Option length         */
        dmsg->dc_opt[j++] = 0xff &  0;  /* Arch - byte 1         */
        dmsg->dc_opt[j++] = 0xff &  0;  /* Arch - byte 2         */

        dmsg->dc_opt[j++] = 0xff & 53;  /* DHCP message type option     */
        dmsg->dc_opt[j++] = 0xff &  1;  /* Option length                */
        dmsg->dc_opt[j++] = 0xff &  1;  /* DHCP Discover message        */
        dmsg->dc_opt[j++] = 0xff &  0;  /* Options padding              */

        dmsg->dc_opt[j++] = 0xff & 55;  /* DHCP parameter request list  */
        dmsg->dc_opt[j++] = 0xff &  4;  /* Option length                */
        dmsg->dc_opt[j++] = 0xff &  1;  /* Request subnet mask          */
        dmsg->dc_opt[j++] = 0xff &  3;  /* Request default router addr->*/
        dmsg->dc_opt[j++] = 0xff & 43;  /* Vendor options */
        dmsg->dc_opt[j++] = 0xff & 60;  /* Vendor class identifier */
        dmsg->dc_opt[j++] = 0xff & 66;  /* Request TFTP Server */
        dmsg->dc_opt[j++] = 0xff & 67;  /* Request Boot file */
        
        dmsg->dc_opt[j++] = 0xff & 60;  /* DHCP PXE Support     */
        dmsg->dc_opt[j++] = 0xff & 32;  /* Option length        */
        
        char* pxe_client_tmp = PXE_CLIENT_STRING;
        for(i = 0; i < PXE_CLIENT_STRING_LEN; i++) {
                dmsg->dc_opt[j++] = 0xff & pxe_client_tmp[i];
        }
        
        dmsg->dc_opt[j++] = 0xff &  0;  /* Options padding              */
        dmsg->dc_opt[j++] = 0xff &  0;  /* Options padding              */
        dmsg->dc_opt[j++] = 0xff &  0;  /* Options padding              */

        return (uint32)((char *)&dmsg->dc_opt[j] - (char *)dmsg + 1);
}