/*
 *      Based on LiMon - BOOTP.
 *
 *      Copyright 1994, 1995, 2000 Neil Russell.
 *      (See License)
 *      Copyright 2000 Roland Borde
 *      Copyright 2000 Paolo Scaffardi
 *      Copyright 2000-2004 Wolfgang Denk, wd@denx.de
 */

#include <common.h>
#include <bootstage.h>
#include <command.h>
#include <env.h>
#include <efi_loader.h>
#include <log.h>
#include <net.h>
#include <rand.h>
#include <uuid.h>
#include <linux/delay.h>
#include <net/tftp.h>
#include "bootp.h"
#ifdef CONFIG_LED_STATUS
#include <status_led.h>
#endif
#ifdef CONFIG_BOOTP_RANDOM_DELAY
#include "net_rand.h"
#endif

#define BOOTP_VENDOR_MAGIC      0x63825363      /* RFC1048 Magic Cookie */

/*
 * The timeout for the initial BOOTP/DHCP request used to be described by a
 * counter of fixed-length timeout periods. CONFIG_NET_RETRY_COUNT represents
 * that counter
 *
 * Now that the timeout periods are variable (exponential backoff and retry)
 * we convert the timeout count to the absolute time it would have take to
 * execute that many retries, and keep sending retry packets until that time
 * is reached.
 */
#define TIMEOUT_MS      ((3 + (CONFIG_NET_RETRY_COUNT * 5)) * 1000)

#define PORT_BOOTPS     67              /* BOOTP server UDP port */
#define PORT_BOOTPC     68              /* BOOTP client UDP port */

#ifndef CONFIG_DHCP_MIN_EXT_LEN         /* minimal length of extension list */
#define CONFIG_DHCP_MIN_EXT_LEN 64
#endif

#ifndef CONFIG_BOOTP_ID_CACHE_SIZE
#define CONFIG_BOOTP_ID_CACHE_SIZE 4
#endif

u32             bootp_ids[CONFIG_BOOTP_ID_CACHE_SIZE];
unsigned int    bootp_num_ids;
int             bootp_try;
ulong           bootp_start;
ulong           bootp_timeout;
char net_nis_domain[32] = {0,}; /* Our NIS domain */
char net_hostname[32] = {0,}; /* Our hostname */
char net_root_path[CONFIG_BOOTP_MAX_ROOT_PATH_LEN] = {0,}; /* Our bootpath */

static ulong time_taken_max;

#if defined(CONFIG_CMD_DHCP)
static dhcp_state_t dhcp_state = INIT;
static u32 dhcp_leasetime;
static struct in_addr dhcp_server_ip;
static u8 dhcp_option_overload;
#define OVERLOAD_FILE 1
#define OVERLOAD_SNAME 2
static void dhcp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
                        unsigned src, unsigned len);

/* For Debug */
#if 0
static char *dhcpmsg2str(int type)
{
        switch (type) {
        case 1:  return "DHCPDISCOVER"; break;
        case 2:  return "DHCPOFFER";    break;
        case 3:  return "DHCPREQUEST";  break;
        case 4:  return "DHCPDECLINE";  break;
        case 5:  return "DHCPACK";      break;
        case 6:  return "DHCPNACK";     break;
        case 7:  return "DHCPRELEASE";  break;
        default: return "UNKNOWN/INVALID MSG TYPE"; break;
        }
}
#endif
#endif

static void bootp_add_id(ulong id)
{
        if (bootp_num_ids >= ARRAY_SIZE(bootp_ids)) {
                size_t size = sizeof(bootp_ids) - sizeof(id);

                memmove(bootp_ids, &bootp_ids[1], size);
                bootp_ids[bootp_num_ids - 1] = id;
        } else {
                bootp_ids[bootp_num_ids] = id;
                bootp_num_ids++;
        }
}

static bool bootp_match_id(ulong id)
{
        unsigned int i;

        for (i = 0; i < bootp_num_ids; i++)
                if (bootp_ids[i] == id)
                        return true;

        return false;
}

static int check_reply_packet(uchar *pkt, unsigned dest, unsigned src,
                              unsigned len)
{
        struct bootp_hdr *bp = (struct bootp_hdr *)pkt;
        int retval = 0;

        if (dest != PORT_BOOTPC || src != PORT_BOOTPS)
                retval = -1;
        else if (len < sizeof(struct bootp_hdr) - OPT_FIELD_SIZE)
                retval = -2;
        else if (bp->bp_op != OP_BOOTREPLY)
                retval = -3;
        else if (bp->bp_htype != HWT_ETHER)
                retval = -4;
        else if (bp->bp_hlen != HWL_ETHER)
                retval = -5;
        else if (!bootp_match_id(net_read_u32(&bp->bp_id)))
                retval = -6;
        else if (memcmp(bp->bp_chaddr, net_ethaddr, HWL_ETHER) != 0)
                retval = -7;

        debug("Filtering pkt = %d\n", retval);

        return retval;
}

static void store_bootp_params(struct bootp_hdr *bp)
{
        struct in_addr tmp_ip;
        bool overwrite_serverip = true;

        if (IS_ENABLED(CONFIG_BOOTP_SERVERIP))
                return;

#if defined(CONFIG_BOOTP_PREFER_SERVERIP)
        overwrite_serverip = false;
#endif

        net_copy_ip(&tmp_ip, &bp->bp_siaddr);
        if (tmp_ip.s_addr != 0 && (overwrite_serverip || !net_server_ip.s_addr))
                net_copy_ip(&net_server_ip, &bp->bp_siaddr);
        memcpy(net_server_ethaddr,
               ((struct ethernet_hdr *)net_rx_packet)->et_src, 6);
        if (
#if defined(CONFIG_CMD_DHCP)
            !(dhcp_option_overload & OVERLOAD_FILE) &&
#endif
            (strlen(bp->bp_file) > 0) &&
            !net_boot_file_name_explicit) {
                copy_filename(net_boot_file_name, bp->bp_file,
                              sizeof(net_boot_file_name));
        }

        debug("net_boot_file_name: %s\n", net_boot_file_name);

        /* Propagate to environment:
         * don't delete exising entry when BOOTP / DHCP reply does
         * not contain a new value
         */
        if (*net_boot_file_name)
                env_set("bootfile", net_boot_file_name);
}

/*
 * Copy parameters of interest from BOOTP_REPLY/DHCP_OFFER packet
 */
static void store_net_params(struct bootp_hdr *bp)
{
#if !defined(CONFIG_SERVERIP_FROM_PROXYDHCP)
        store_bootp_params(bp);
#endif
        net_copy_ip(&net_ip, &bp->bp_yiaddr);
}

static int truncate_sz(const char *name, int maxlen, int curlen)
{
        if (curlen >= maxlen) {
                printf("*** WARNING: %s is too long (%d - max: %d)"
                        " - truncated\n", name, curlen, maxlen);
                curlen = maxlen - 1;
        }
        return curlen;
}

#if !defined(CONFIG_CMD_DHCP)

static void bootp_process_vendor_field(u8 *ext)
{
        int size = *(ext + 1);

        debug("[BOOTP] Processing extension %d... (%d bytes)\n", *ext,
              *(ext + 1));

        net_boot_file_expected_size_in_blocks = 0;

        switch (*ext) {
                /* Fixed length fields */
        case 1:                 /* Subnet mask */
                if (net_netmask.s_addr == 0)
                        net_copy_ip(&net_netmask, (struct in_addr *)(ext + 2));
                break;
        case 2:                 /* Time offset - Not yet supported */
                break;
                /* Variable length fields */
        case 3:                 /* Gateways list */
                if (net_gateway.s_addr == 0)
                        net_copy_ip(&net_gateway, (struct in_addr *)(ext + 2));
                break;
        case 4:                 /* Time server - Not yet supported */
                break;
        case 5:                 /* IEN-116 name server - Not yet supported */
                break;
        case 6:
                if (net_dns_server.s_addr == 0)
                        net_copy_ip(&net_dns_server,
                                    (struct in_addr *)(ext + 2));
#if defined(CONFIG_BOOTP_DNS2)
                if ((net_dns_server2.s_addr == 0) && (size > 4))
                        net_copy_ip(&net_dns_server2,
                                    (struct in_addr *)(ext + 2 + 4));
#endif
                break;
        case 7:                 /* Log server - Not yet supported */
                break;
        case 8:                 /* Cookie/Quote server - Not yet supported */
                break;
        case 9:                 /* LPR server - Not yet supported */
                break;
        case 10:                /* Impress server - Not yet supported */
                break;
        case 11:                /* RPL server - Not yet supported */
                break;
        case 12:                /* Host name */
                if (net_hostname[0] == 0) {
                        size = truncate_sz("Host Name",
                                sizeof(net_hostname), size);
                        memcpy(&net_hostname, ext + 2, size);
                        net_hostname[size] = 0;
                }
                break;
        case 13:                /* Boot file size */
                if (size == 2)
                        net_boot_file_expected_size_in_blocks =
                                ntohs(*(ushort *)(ext + 2));
                else if (size == 4)
                        net_boot_file_expected_size_in_blocks =
                                ntohl(*(ulong *)(ext + 2));
                break;
        case 14:                /* Merit dump file - Not yet supported */
                break;
        case 15:                /* Domain name - Not yet supported */
                break;
        case 16:                /* Swap server - Not yet supported */
                break;
        case 17:                /* Root path */
                if (net_root_path[0] == 0) {
                        size = truncate_sz("Root Path",
                                sizeof(net_root_path), size);
                        memcpy(&net_root_path, ext + 2, size);
                        net_root_path[size] = 0;
                }
                break;
        case 18:                /* Extension path - Not yet supported */
                /*
                 * This can be used to send the information of the
                 * vendor area in another file that the client can
                 * access via TFTP.
                 */
                break;
                /* IP host layer fields */
        case 40:                /* NIS Domain name */
                if (net_nis_domain[0] == 0) {
                        size = truncate_sz("NIS Domain Name",
                                sizeof(net_nis_domain), size);
                        memcpy(&net_nis_domain, ext + 2, size);
                        net_nis_domain[size] = 0;
                }
                break;
#if defined(CONFIG_CMD_SNTP) && defined(CONFIG_BOOTP_NTPSERVER)
        case 42:        /* NTP server IP */
                net_copy_ip(&net_ntp_server, (struct in_addr *)(ext + 2));
                break;
#endif
                /* Application layer fields */
        case 43:                /* Vendor specific info - Not yet supported */
                /*
                 * Binary information to exchange specific
                 * product information.
                 */
                break;
                /* Reserved (custom) fields (128..254) */
        }
}

static void bootp_process_vendor(u8 *ext, int size)
{
        u8 *end = ext + size;

        debug("[BOOTP] Checking extension (%d bytes)...\n", size);

        while ((ext < end) && (*ext != 0xff)) {
                if (*ext == 0) {
                        ext++;
                } else {
                        u8 *opt = ext;

                        ext += ext[1] + 2;
                        if (ext <= end)
                                bootp_process_vendor_field(opt);
                }
        }

        debug("[BOOTP] Received fields:\n");
        if (net_netmask.s_addr)
                debug("net_netmask : %pI4\n", &net_netmask);

        if (net_gateway.s_addr)
                debug("net_gateway      : %pI4", &net_gateway);

        if (net_boot_file_expected_size_in_blocks)
                debug("net_boot_file_expected_size_in_blocks : %d\n",
                      net_boot_file_expected_size_in_blocks);

        if (net_hostname[0])
                debug("net_hostname  : %s\n", net_hostname);

        if (net_root_path[0])
                debug("net_root_path  : %s\n", net_root_path);

        if (net_nis_domain[0])
                debug("net_nis_domain : %s\n", net_nis_domain);

#if defined(CONFIG_CMD_SNTP) && defined(CONFIG_BOOTP_NTPSERVER)
        if (net_ntp_server.s_addr)
                debug("net_ntp_server : %pI4\n", &net_ntp_server);
#endif
}

/*
 *      Handle a BOOTP received packet.
 */
static void bootp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
                          unsigned src, unsigned len)
{
        struct bootp_hdr *bp;

        debug("got BOOTP packet (src=%d, dst=%d, len=%d want_len=%zu)\n",
              src, dest, len, sizeof(struct bootp_hdr));

        bp = (struct bootp_hdr *)pkt;

        /* Filter out pkts we don't want */
        if (check_reply_packet(pkt, dest, src, len))
                return;

        /*
         *      Got a good BOOTP reply.  Copy the data into our variables.
         */
#if defined(CONFIG_LED_STATUS) && defined(CONFIG_LED_STATUS_BOOT_ENABLE)
        status_led_set(CONFIG_LED_STATUS_BOOT, CONFIG_LED_STATUS_OFF);
#endif

        store_net_params(bp);           /* Store net parameters from reply */

        /* Retrieve extended information (we must parse the vendor area) */
        if (net_read_u32((u32 *)&bp->bp_vend[0]) == htonl(BOOTP_VENDOR_MAGIC))
                bootp_process_vendor((uchar *)&bp->bp_vend[4], len);

        net_set_timeout_handler(0, (thand_f *)0);
        bootstage_mark_name(BOOTSTAGE_ID_BOOTP_STOP, "bootp_stop");

        debug("Got good BOOTP\n");

        net_auto_load();
}
#endif

/*
 *      Timeout on BOOTP/DHCP request.
 */
static void bootp_timeout_handler(void)
{
        ulong time_taken = get_timer(bootp_start);

        if (time_taken >= time_taken_max) {
#ifdef CONFIG_BOOTP_MAY_FAIL
                char *ethrotate;

                ethrotate = env_get("ethrotate");
                if ((ethrotate && strcmp(ethrotate, "no") == 0) ||
                    net_restart_wrap) {
                        puts("\nRetry time exceeded\n");
                        net_set_state(NETLOOP_FAIL);
                } else
#endif
                {
                        puts("\nRetry time exceeded; starting again\n");
                        net_start_again();
                }
        } else {
                bootp_timeout *= 2;
                if (bootp_timeout > 2000)
                        bootp_timeout = 2000;
                net_set_timeout_handler(bootp_timeout, bootp_timeout_handler);
                bootp_request();
        }
}

#define put_vci(e, str)                                         \
        do {                                                    \
                size_t vci_strlen = strlen(str);                \
                *e++ = 60;      /* Vendor Class Identifier */   \
                *e++ = vci_strlen;                              \
                memcpy(e, str, vci_strlen);                     \
                e += vci_strlen;                                \
        } while (0)

static u8 *add_vci(u8 *e)
{
        char *vci = NULL;
        char *env_vci = env_get("bootp_vci");

#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_NET_VCI_STRING)
        vci = CONFIG_SPL_NET_VCI_STRING;
#elif defined(CONFIG_BOOTP_VCI_STRING)
        vci = CONFIG_BOOTP_VCI_STRING;
#endif

        if (env_vci)
                vci = env_vci;

        if (vci)
                put_vci(e, vci);

        return e;
}

/*
 *      Initialize BOOTP extension fields in the request.
 */
#if defined(CONFIG_CMD_DHCP)
static int dhcp_extended(u8 *e, int message_type, struct in_addr server_ip,
                        struct in_addr requested_ip)
{
        u8 *start = e;
        u8 *cnt;
#ifdef CONFIG_LIB_UUID
        char *uuid;
#endif
        int clientarch = -1;

#if defined(CONFIG_BOOTP_VENDOREX)
        u8 *x;
#endif
#if defined(CONFIG_BOOTP_SEND_HOSTNAME)
        char *hostname;
#endif

        *e++ = 99;              /* RFC1048 Magic Cookie */
        *e++ = 130;
        *e++ = 83;
        *e++ = 99;

        *e++ = 53;              /* DHCP Message Type */
        *e++ = 1;
        *e++ = message_type;

        *e++ = 57;              /* Maximum DHCP Message Size */
        *e++ = 2;
        *e++ = (576 - 312 + OPT_FIELD_SIZE) >> 8;
        *e++ = (576 - 312 + OPT_FIELD_SIZE) & 0xff;

        if (server_ip.s_addr) {
                int tmp = ntohl(server_ip.s_addr);

                *e++ = 54;      /* ServerID */
                *e++ = 4;
                *e++ = tmp >> 24;
                *e++ = tmp >> 16;
                *e++ = tmp >> 8;
                *e++ = tmp & 0xff;
        }

        if (requested_ip.s_addr) {
                int tmp = ntohl(requested_ip.s_addr);

                *e++ = 50;      /* Requested IP */
                *e++ = 4;
                *e++ = tmp >> 24;
                *e++ = tmp >> 16;
                *e++ = tmp >> 8;
                *e++ = tmp & 0xff;
        }
#if defined(CONFIG_BOOTP_SEND_HOSTNAME)
        hostname = env_get("hostname");
        if (hostname) {
                int hostnamelen = strlen(hostname);

                *e++ = 12;      /* Hostname */
                *e++ = hostnamelen;
                memcpy(e, hostname, hostnamelen);
                e += hostnamelen;
        }
#endif

#ifdef CONFIG_BOOTP_PXE_CLIENTARCH
        clientarch = CONFIG_BOOTP_PXE_CLIENTARCH;
#endif

        if (env_get("bootp_arch"))
                clientarch = env_get_ulong("bootp_arch", 16, clientarch);

        if (clientarch > 0) {
                *e++ = 93;      /* Client System Architecture */
                *e++ = 2;
                *e++ = (clientarch >> 8) & 0xff;
                *e++ = clientarch & 0xff;
        }

        *e++ = 94;      /* Client Network Interface Identifier */
        *e++ = 3;
        *e++ = 1;       /* type field for UNDI */
        *e++ = 0;       /* major revision */
        *e++ = 0;       /* minor revision */

#ifdef CONFIG_LIB_UUID
        uuid = env_get("pxeuuid");

        if (uuid) {
                if (uuid_str_valid(uuid)) {
                        *e++ = 97;      /* Client Machine Identifier */
                        *e++ = 17;
                        *e++ = 0;       /* type 0 - UUID */

                        uuid_str_to_bin(uuid, e, UUID_STR_FORMAT_STD);
                        e += 16;
                } else {
                        printf("Invalid pxeuuid: %s\n", uuid);
                }
        }
#endif

        e = add_vci(e);

#if defined(CONFIG_BOOTP_VENDOREX)
        x = dhcp_vendorex_prep(e);
        if (x)
                return x - start;
#endif

        *e++ = 55;              /* Parameter Request List */
         cnt = e++;             /* Pointer to count of requested items */
        *cnt = 0;
#if defined(CONFIG_BOOTP_SUBNETMASK)
        *e++  = 1;              /* Subnet Mask */
        *cnt += 1;
#endif
#if defined(CONFIG_BOOTP_TIMEOFFSET)
        *e++  = 2;
        *cnt += 1;
#endif
#if defined(CONFIG_BOOTP_GATEWAY)
        *e++  = 3;              /* Router Option */
        *cnt += 1;
#endif
#if defined(CONFIG_BOOTP_DNS)
        *e++  = 6;              /* DNS Server(s) */
        *cnt += 1;
#endif
#if defined(CONFIG_BOOTP_HOSTNAME)
        *e++  = 12;             /* Hostname */
        *cnt += 1;
#endif
#if defined(CONFIG_BOOTP_BOOTFILESIZE)
        *e++  = 13;             /* Boot File Size */
        *cnt += 1;
#endif
#if defined(CONFIG_BOOTP_BOOTPATH)
        *e++  = 17;             /* Boot path */
        *cnt += 1;
#endif
#if defined(CONFIG_BOOTP_NISDOMAIN)
        *e++  = 40;             /* NIS Domain name request */
        *cnt += 1;
#endif
#if defined(CONFIG_BOOTP_NTPSERVER)
        *e++  = 42;
        *cnt += 1;
#endif
        /* no options, so back up to avoid sending an empty request list */
        if (*cnt == 0)
                e -= 2;

        *e++  = 255;            /* End of the list */

        /* Pad to minimal length */
#ifdef  CONFIG_DHCP_MIN_EXT_LEN
        while ((e - start) < CONFIG_DHCP_MIN_EXT_LEN)
                *e++ = 0;
#endif

        return e - start;
}

#else
/*
 * Warning: no field size check - change CONFIG_BOOTP_* at your own risk!
 */
static int bootp_extended(u8 *e)
{
        u8 *start = e;

        *e++ = 99;              /* RFC1048 Magic Cookie */
        *e++ = 130;
        *e++ = 83;
        *e++ = 99;

#if defined(CONFIG_CMD_DHCP)
        *e++ = 53;              /* DHCP Message Type */
        *e++ = 1;
        *e++ = DHCP_DISCOVER;

        *e++ = 57;              /* Maximum DHCP Message Size */
        *e++ = 2;
        *e++ = (576 - 312 + OPT_FIELD_SIZE) >> 16;
        *e++ = (576 - 312 + OPT_FIELD_SIZE) & 0xff;
#endif

        e = add_vci(e);

#if defined(CONFIG_BOOTP_SUBNETMASK)
        *e++ = 1;               /* Subnet mask request */
        *e++ = 4;
        e   += 4;
#endif

#if defined(CONFIG_BOOTP_GATEWAY)
        *e++ = 3;               /* Default gateway request */
        *e++ = 4;
        e   += 4;
#endif

#if defined(CONFIG_BOOTP_DNS)
        *e++ = 6;               /* Domain Name Server */
        *e++ = 4;
        e   += 4;
#endif

#if defined(CONFIG_BOOTP_HOSTNAME)
        *e++ = 12;              /* Host name request */
        *e++ = 32;
        e   += 32;
#endif

#if defined(CONFIG_BOOTP_BOOTFILESIZE)
        *e++ = 13;              /* Boot file size */
        *e++ = 2;
        e   += 2;
#endif

#if defined(CONFIG_BOOTP_BOOTPATH)
        *e++ = 17;              /* Boot path */
        *e++ = 32;
        e   += 32;
#endif

#if defined(CONFIG_BOOTP_NISDOMAIN)
        *e++ = 40;              /* NIS Domain name request */
        *e++ = 32;
        e   += 32;
#endif
#if defined(CONFIG_BOOTP_NTPSERVER)
        *e++ = 42;
        *e++ = 4;
        e   += 4;
#endif

        *e++ = 255;             /* End of the list */

        /*
         * If nothing in list, remove it altogether. Some DHCP servers get
         * upset by this minor faux pas and do not respond at all.
         */
        if (e == start + 3) {
                printf("*** Warning: no DHCP options requested\n");
                e -= 3;
        }

        return e - start;
}
#endif

void bootp_reset(void)
{
        bootp_num_ids = 0;
        bootp_try = 0;
        bootp_start = get_timer(0);
        bootp_timeout = 250;
}

void bootp_request(void)
{
        uchar *pkt, *iphdr;
        struct bootp_hdr *bp;
        int extlen, pktlen, iplen;
        int eth_hdr_size;
#ifdef CONFIG_BOOTP_RANDOM_DELAY
        ulong rand_ms;
#endif
        u32 bootp_id;
        struct in_addr zero_ip;
        struct in_addr bcast_ip;
        char *ep;  /* Environment pointer */

        bootstage_mark_name(BOOTSTAGE_ID_BOOTP_START, "bootp_start");
#if defined(CONFIG_CMD_DHCP)
        dhcp_state = INIT;
#endif

        ep = env_get("bootpretryperiod");
        if (ep != NULL)
                time_taken_max = dectoul(ep, NULL);
        else
                time_taken_max = TIMEOUT_MS;

#ifdef CONFIG_BOOTP_RANDOM_DELAY                /* Random BOOTP delay */
        if (bootp_try == 0)
                srand_mac();

        if (bootp_try <= 2)     /* Start with max 1024 * 1ms */
                rand_ms = rand() >> (22 - bootp_try);
        else            /* After 3rd BOOTP request max 8192 * 1ms */
                rand_ms = rand() >> 19;

        printf("Random delay: %ld ms...\n", rand_ms);
        mdelay(rand_ms);

#endif  /* CONFIG_BOOTP_RANDOM_DELAY */

        printf("BOOTP broadcast %d\n", ++bootp_try);
        pkt = net_tx_packet;
        memset((void *)pkt, 0, PKTSIZE);

        eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_IP);
        pkt += eth_hdr_size;

        /*
         * Next line results in incorrect packet size being transmitted,
         * resulting in errors in some DHCP servers, reporting missing bytes.
         * Size must be set in packet header after extension length has been
         * determined.
         * C. Hallinan, DS4.COM, Inc.
         */
        /* net_set_udp_header(pkt, 0xFFFFFFFFL, PORT_BOOTPS, PORT_BOOTPC,
                sizeof (struct bootp_hdr)); */
        iphdr = pkt;    /* We need this later for net_set_udp_header() */
        pkt += IP_UDP_HDR_SIZE;

        bp = (struct bootp_hdr *)pkt;
        bp->bp_op = OP_BOOTREQUEST;
        bp->bp_htype = HWT_ETHER;
        bp->bp_hlen = HWL_ETHER;
        bp->bp_hops = 0;
        /*
         * according to RFC1542, should be 0 on first request, secs since
         * first request otherwise
         */
        bp->bp_secs = htons(get_timer(bootp_start) / 1000);
        zero_ip.s_addr = 0;
        net_write_ip(&bp->bp_ciaddr, zero_ip);
        net_write_ip(&bp->bp_yiaddr, zero_ip);
        net_write_ip(&bp->bp_siaddr, zero_ip);
        net_write_ip(&bp->bp_giaddr, zero_ip);
        memcpy(bp->bp_chaddr, net_ethaddr, 6);
        copy_filename(bp->bp_file, net_boot_file_name, sizeof(bp->bp_file));

        /* Request additional information from the BOOTP/DHCP server */
#if defined(CONFIG_CMD_DHCP)
        extlen = dhcp_extended((u8 *)bp->bp_vend, DHCP_DISCOVER, zero_ip,
                               zero_ip);
#else
        extlen = bootp_extended((u8 *)bp->bp_vend);
#endif

        /*
         *      Bootp ID is the lower 4 bytes of our ethernet address
         *      plus the current time in ms.
         */
        bootp_id = ((u32)net_ethaddr[2] << 24)
                | ((u32)net_ethaddr[3] << 16)
                | ((u32)net_ethaddr[4] << 8)
                | (u32)net_ethaddr[5];
        bootp_id += get_timer(0);
        bootp_id = htonl(bootp_id);
        bootp_add_id(bootp_id);
        net_copy_u32(&bp->bp_id, &bootp_id);

        /*
         * Calculate proper packet lengths taking into account the
         * variable size of the options field
         */
        iplen = BOOTP_HDR_SIZE - OPT_FIELD_SIZE + extlen;
        pktlen = eth_hdr_size + IP_UDP_HDR_SIZE + iplen;
        bcast_ip.s_addr = 0xFFFFFFFFL;
        net_set_udp_header(iphdr, bcast_ip, PORT_BOOTPS, PORT_BOOTPC, iplen);
        net_set_timeout_handler(bootp_timeout, bootp_timeout_handler);

#if defined(CONFIG_CMD_DHCP)
        dhcp_state = SELECTING;
        net_set_udp_handler(dhcp_handler);
#else
        net_set_udp_handler(bootp_handler);
#endif
        net_send_packet(net_tx_packet, pktlen);
}

#if defined(CONFIG_CMD_DHCP)
static void dhcp_process_options(uchar *popt, uchar *end)
{
        int oplen, size;
#if defined(CONFIG_CMD_SNTP) && defined(CONFIG_BOOTP_TIMEOFFSET)
        int *to_ptr;
#endif

        while (popt < end && *popt != 0xff) {
                oplen = *(popt + 1);
                switch (*popt) {
                case 0:
                        oplen = -1; /* Pad omits len byte */
                        break;
                case 1:
                        net_copy_ip(&net_netmask, (popt + 2));
                        break;
#if defined(CONFIG_CMD_SNTP) && defined(CONFIG_BOOTP_TIMEOFFSET)
                case 2:         /* Time offset  */
                        to_ptr = &net_ntp_time_offset;
                        net_copy_u32((u32 *)to_ptr, (u32 *)(popt + 2));
                        net_ntp_time_offset = ntohl(net_ntp_time_offset);
                        break;
#endif
                case 3:
                        net_copy_ip(&net_gateway, (popt + 2));
                        break;
                case 6:
                        net_copy_ip(&net_dns_server, (popt + 2));
#if defined(CONFIG_BOOTP_DNS2)
                        if (*(popt + 1) > 4)
                                net_copy_ip(&net_dns_server2, (popt + 2 + 4));
#endif
                        break;
                case 12:
                        size = truncate_sz("Host Name",
                                sizeof(net_hostname), oplen);
                        memcpy(&net_hostname, popt + 2, size);
                        net_hostname[size] = 0;
                        break;
                case 15:        /* Ignore Domain Name Option */
                        break;
                case 17:
                        size = truncate_sz("Root Path",
                                sizeof(net_root_path), oplen);
                        memcpy(&net_root_path, popt + 2, size);
                        net_root_path[size] = 0;
                        break;
                case 28:        /* Ignore Broadcast Address Option */
                        break;
#if defined(CONFIG_CMD_SNTP) && defined(CONFIG_BOOTP_NTPSERVER)
                case 42:        /* NTP server IP */
                        net_copy_ip(&net_ntp_server, (popt + 2));
                        break;
#endif
                case 51:
                        net_copy_u32(&dhcp_leasetime, (u32 *)(popt + 2));
                        break;
                case 52:
                        dhcp_option_overload = popt[2];
                        break;
                case 53:        /* Ignore Message Type Option */
                        break;
                case 54:
                        net_copy_ip(&dhcp_server_ip, (popt + 2));
                        break;
                case 58:        /* Ignore Renewal Time Option */
                        break;
                case 59:        /* Ignore Rebinding Time Option */
                        break;
                case 66:        /* Ignore TFTP server name */
                        break;
                case 67:        /* Bootfile option */
                        if (!net_boot_file_name_explicit) {
                                size = truncate_sz("Bootfile",
                                                   sizeof(net_boot_file_name),
                                                   oplen);
                                memcpy(&net_boot_file_name, popt + 2, size);
                                net_boot_file_name[size] = 0;
                        }
                        break;
                default:
#if defined(CONFIG_BOOTP_VENDOREX)
                        if (dhcp_vendorex_proc(popt))
                                break;
#endif
                        printf("*** Unhandled DHCP Option in OFFER/ACK:"
                               " %d\n", *popt);
                        break;
                }
                popt += oplen + 2;      /* Process next option */
        }
}

static void dhcp_packet_process_options(struct bootp_hdr *bp)
{
        uchar *popt = (uchar *)&bp->bp_vend[4];
        uchar *end = popt + BOOTP_HDR_SIZE;

        if (net_read_u32((u32 *)&bp->bp_vend[0]) != htonl(BOOTP_VENDOR_MAGIC))
                return;

        dhcp_option_overload = 0;

        /*
         * The 'options' field MUST be interpreted first, 'file' next,
         * 'sname' last.
         */
        dhcp_process_options(popt, end);

        if (dhcp_option_overload & OVERLOAD_FILE) {
                popt = (uchar *)bp->bp_file;
                end = popt + sizeof(bp->bp_file);
                dhcp_process_options(popt, end);
        }

        if (dhcp_option_overload & OVERLOAD_SNAME) {
                popt = (uchar *)bp->bp_sname;
                end = popt + sizeof(bp->bp_sname);
                dhcp_process_options(popt, end);
        }
}

static int dhcp_message_type(unsigned char *popt)
{
        if (net_read_u32((u32 *)popt) != htonl(BOOTP_VENDOR_MAGIC))
                return -1;

        popt += 4;
        while (*popt != 0xff) {
                if (*popt == 53)        /* DHCP Message Type */
                        return *(popt + 2);
                if (*popt == 0) {
                        /* Pad */
                        popt += 1;
                } else {
                        /* Scan through all options */
                        popt += *(popt + 1) + 2;
                }
        }
        return -1;
}

static void dhcp_send_request_packet(struct bootp_hdr *bp_offer)
{
        uchar *pkt, *iphdr;
        struct bootp_hdr *bp;
        int pktlen, iplen, extlen;
        int eth_hdr_size;
        struct in_addr offered_ip;
        struct in_addr zero_ip;
        struct in_addr bcast_ip;

        debug("dhcp_send_request_packet: Sending DHCPREQUEST\n");
        pkt = net_tx_packet;
        memset((void *)pkt, 0, PKTSIZE);

        eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_IP);
        pkt += eth_hdr_size;

        iphdr = pkt;    /* We'll need this later to set proper pkt size */
        pkt += IP_UDP_HDR_SIZE;

        bp = (struct bootp_hdr *)pkt;
        bp->bp_op = OP_BOOTREQUEST;
        bp->bp_htype = HWT_ETHER;
        bp->bp_hlen = HWL_ETHER;

        bp->bp_hops = 0;
        bp->bp_secs = htons(get_timer(bootp_start) / 1000);
        /* Do not set the client IP, your IP, or server IP yet, since it
         * hasn't been ACK'ed by the server yet */

        /*
         * RFC3046 requires Relay Agents to discard packets with
         * nonzero and offered giaddr
         */
        zero_ip.s_addr = 0;
        net_write_ip(&bp->bp_giaddr, zero_ip);

        memcpy(bp->bp_chaddr, net_ethaddr, 6);
        copy_filename(bp->bp_file, net_boot_file_name, sizeof(bp->bp_file));

        /*
         * ID is the id of the OFFER packet
         */

        net_copy_u32(&bp->bp_id, &bp_offer->bp_id);

        /*
         * Copy options from OFFER packet if present
         */

        /* Copy offered IP into the parameters request list */
        net_copy_ip(&offered_ip, &bp_offer->bp_yiaddr);
        extlen = dhcp_extended((u8 *)bp->bp_vend, DHCP_REQUEST,
                dhcp_server_ip, offered_ip);

        iplen = BOOTP_HDR_SIZE - OPT_FIELD_SIZE + extlen;
        pktlen = eth_hdr_size + IP_UDP_HDR_SIZE + iplen;
        bcast_ip.s_addr = 0xFFFFFFFFL;
        net_set_udp_header(iphdr, bcast_ip, PORT_BOOTPS, PORT_BOOTPC, iplen);

        debug("Transmitting DHCPREQUEST packet: len = %d\n", pktlen);
        net_send_packet(net_tx_packet, pktlen);
}

/*
 *      Handle DHCP received packets.
 */
static void dhcp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
                         unsigned src, unsigned len)
{
        struct bootp_hdr *bp = (struct bootp_hdr *)pkt;

        debug("DHCPHandler: got packet: (src=%d, dst=%d, len=%d) state: %d\n",
              src, dest, len, dhcp_state);

        /* Filter out pkts we don't want */
        if (check_reply_packet(pkt, dest, src, len))
                return;

        debug("DHCPHandler: got DHCP packet: (src=%d, dst=%d, len=%d) state: "
              "%d\n", src, dest, len, dhcp_state);

        if (net_read_ip(&bp->bp_yiaddr).s_addr == 0) {
#if defined(CONFIG_SERVERIP_FROM_PROXYDHCP)
                store_bootp_params(bp);
#endif
                return;
        }

        switch (dhcp_state) {
        case SELECTING:
                /*
                 * Wait an appropriate time for any potential DHCPOFFER packets
                 * to arrive.  Then select one, and generate DHCPREQUEST
                 * response.  If filename is in format we recognize, assume it
                 * is a valid OFFER from a server we want.
                 */
                debug("DHCP: state=SELECTING bp_file: \"%s\"\n", bp->bp_file);
#ifdef CONFIG_SYS_BOOTFILE_PREFIX
                if (strncmp(bp->bp_file,
                            CONFIG_SYS_BOOTFILE_PREFIX,
                            strlen(CONFIG_SYS_BOOTFILE_PREFIX)) == 0) {
#endif  /* CONFIG_SYS_BOOTFILE_PREFIX */
                        dhcp_packet_process_options(bp);
                        if (CONFIG_IS_ENABLED(EFI_LOADER) &&
                            CONFIG_IS_ENABLED(NETDEVICES))
                                efi_net_set_dhcp_ack(pkt, len);

#if defined(CONFIG_SERVERIP_FROM_PROXYDHCP)
                        if (!net_server_ip.s_addr)
                                udelay(CONFIG_SERVERIP_FROM_PROXYDHCP_DELAY_MS *
                                        1000);
#endif  /* CONFIG_SERVERIP_FROM_PROXYDHCP */

                        debug("TRANSITIONING TO REQUESTING STATE\n");
                        dhcp_state = REQUESTING;

                        net_set_timeout_handler(5000, bootp_timeout_handler);
                        dhcp_send_request_packet(bp);
#ifdef CONFIG_SYS_BOOTFILE_PREFIX
                }
#endif  /* CONFIG_SYS_BOOTFILE_PREFIX */

                return;
                break;
        case REQUESTING:
                debug("DHCP State: REQUESTING\n");

                if (dhcp_message_type((u8 *)bp->bp_vend) == DHCP_ACK) {
                        dhcp_packet_process_options(bp);
                        /* Store net params from reply */
                        store_net_params(bp);
                        dhcp_state = BOUND;
                        printf("DHCP client bound to address %pI4 (%lu ms)\n",
                               &net_ip, get_timer(bootp_start));
                        net_set_timeout_handler(0, (thand_f *)0);
                        bootstage_mark_name(BOOTSTAGE_ID_BOOTP_STOP,
                                            "bootp_stop");

                        net_auto_load();
                        return;
                }
                break;
        case BOUND:
                /* DHCP client bound to address */
                break;
        default:
                puts("DHCP: INVALID STATE\n");
                break;
        }
}

void dhcp_request(void)
{
        bootp_request();
}
#endif  /* CONFIG_CMD_DHCP */