/*
 * Copyright 1994, 1995, 2000 Neil Russell.
 * (See License)
 * Copyright 2000, 2001 DENX Software Engineering, Wolfgang Denk, wd@denx.de
 * Copyright 2011 Comelit Group SpA,
 *                Luca Ceresoli <luca.ceresoli@comelit.it>
 */

#include <common.h>
#include <command.h>
#include <net.h>
#include "tftp.h"
#include "bootp.h"

/* Well known TFTP port # */
#define WELL_KNOWN_PORT 69
/* Millisecs to timeout for lost pkt */
#define TIMEOUT         5000UL
#ifndef CONFIG_NET_RETRY_COUNT
/* # of timeouts before giving up */
# define TIMEOUT_COUNT  10
#else
# define TIMEOUT_COUNT  (CONFIG_NET_RETRY_COUNT * 2)
#endif
/* Number of "loading" hashes per line (for checking the image size) */
#define HASHES_PER_LINE 65

/*
 *      TFTP operations.
 */
#define TFTP_RRQ        1
#define TFTP_WRQ        2
#define TFTP_DATA       3
#define TFTP_ACK        4
#define TFTP_ERROR      5
#define TFTP_OACK       6

static ulong TftpTimeoutMSecs = TIMEOUT;
static int TftpTimeoutCountMax = TIMEOUT_COUNT;

/*
 * These globals govern the timeout behavior when attempting a connection to a
 * TFTP server. TftpRRQTimeoutMSecs specifies the number of milliseconds to
 * wait for the server to respond to initial connection. Second global,
 * TftpRRQTimeoutCountMax, gives the number of such connection retries.
 * TftpRRQTimeoutCountMax must be non-negative and TftpRRQTimeoutMSecs must be
 * positive. The globals are meant to be set (and restored) by code needing
 * non-standard timeout behavior when initiating a TFTP transfer.
 */
ulong TftpRRQTimeoutMSecs = TIMEOUT;
int TftpRRQTimeoutCountMax = TIMEOUT_COUNT;

enum {
        TFTP_ERR_UNDEFINED           = 0,
        TFTP_ERR_FILE_NOT_FOUND      = 1,
        TFTP_ERR_ACCESS_DENIED       = 2,
        TFTP_ERR_DISK_FULL           = 3,
        TFTP_ERR_UNEXPECTED_OPCODE   = 4,
        TFTP_ERR_UNKNOWN_TRANSFER_ID  = 5,
        TFTP_ERR_FILE_ALREADY_EXISTS = 6,
};

static IPaddr_t TftpRemoteIP;
/* The UDP port at their end */
static int      TftpRemotePort;
/* The UDP port at our end */
static int      TftpOurPort;
static int      TftpTimeoutCount;
/* packet sequence number */
static ulong    TftpBlock;
/* last packet sequence number received */
static ulong    TftpLastBlock;
/* count of sequence number wraparounds */
static ulong    TftpBlockWrap;
/* memory offset due to wrapping */
static ulong    TftpBlockWrapOffset;
static int      TftpState;
#ifdef CONFIG_TFTP_TSIZE
/* The file size reported by the server */
static int      TftpTsize;
/* The number of hashes we printed */
static short    TftpNumchars;
#endif

#define STATE_SEND_RRQ  1
#define STATE_DATA      2
#define STATE_TOO_LARGE 3
#define STATE_BAD_MAGIC 4
#define STATE_OACK      5
#define STATE_RECV_WRQ  6

/* default TFTP block size */
#define TFTP_BLOCK_SIZE         512
/* sequence number is 16 bit */
#define TFTP_SEQUENCE_SIZE      ((ulong)(1<<16))

#define DEFAULT_NAME_LEN        (8 + 4 + 1)
static char default_filename[DEFAULT_NAME_LEN];

#ifndef CONFIG_TFTP_FILE_NAME_MAX_LEN
#define MAX_LEN 128
#else
#define MAX_LEN CONFIG_TFTP_FILE_NAME_MAX_LEN
#endif

static char tftp_filename[MAX_LEN];

#ifdef CONFIG_SYS_DIRECT_FLASH_TFTP
extern flash_info_t flash_info[];
#endif

/* 512 is poor choice for ethernet, MTU is typically 1500.
 * Minus eth.hdrs thats 1468.  Can get 2x better throughput with
 * almost-MTU block sizes.  At least try... fall back to 512 if need be.
 * (but those using CONFIG_IP_DEFRAG may want to set a larger block in cfg file)
 */
#ifdef CONFIG_TFTP_BLOCKSIZE
#define TFTP_MTU_BLOCKSIZE CONFIG_TFTP_BLOCKSIZE
#else
#define TFTP_MTU_BLOCKSIZE 1468
#endif

static unsigned short TftpBlkSize = TFTP_BLOCK_SIZE;
static unsigned short TftpBlkSizeOption = TFTP_MTU_BLOCKSIZE;

#ifdef CONFIG_MCAST_TFTP
#include <malloc.h>
#define MTFTP_BITMAPSIZE        0x1000
static unsigned *Bitmap;
static int PrevBitmapHole, Mapsize = MTFTP_BITMAPSIZE;
static uchar ProhibitMcast, MasterClient;
static uchar Multicast;
extern IPaddr_t Mcast_addr;
static int Mcast_port;
static ulong TftpEndingBlock; /* can get 'last' block before done..*/

static void parse_multicast_oack(char *pkt, int len);

static void
mcast_cleanup(void)
{
        if (Mcast_addr)
                eth_mcast_join(Mcast_addr, 0);
        if (Bitmap)
                free(Bitmap);
        Bitmap = NULL;
        Mcast_addr = Multicast = Mcast_port = 0;
        TftpEndingBlock = -1;
}

#endif  /* CONFIG_MCAST_TFTP */

static __inline__ void
store_block(unsigned block, uchar *src, unsigned len)
{
        ulong offset = block * TftpBlkSize + TftpBlockWrapOffset;
        ulong newsize = offset + len;
#ifdef CONFIG_SYS_DIRECT_FLASH_TFTP
        int i, rc = 0;

        for (i = 0; i < CONFIG_SYS_MAX_FLASH_BANKS; i++) {
                /* start address in flash? */
                if (flash_info[i].flash_id == FLASH_UNKNOWN)
                        continue;
                if (load_addr + offset >= flash_info[i].start[0]) {
                        rc = 1;
                        break;
                }
        }

        if (rc) { /* Flash is destination for this packet */
                rc = flash_write((char *)src, (ulong)(load_addr+offset), len);
                if (rc) {
                        flash_perror(rc);
                        NetState = NETLOOP_FAIL;
                        return;
                }
        }
        else
#endif /* CONFIG_SYS_DIRECT_FLASH_TFTP */
        {
                (void)memcpy((void *)(load_addr + offset), src, len);
        }
#ifdef CONFIG_MCAST_TFTP
        if (Multicast)
                ext2_set_bit(block, Bitmap);
#endif

        if (NetBootFileXferSize < newsize)
                NetBootFileXferSize = newsize;
}

static void TftpSend(void);
static void TftpTimeout(void);

/**********************************************************************/

static void
TftpSend(void)
{
        volatile uchar *pkt;
        volatile uchar *xp;
        int             len = 0;
        volatile ushort *s;

#ifdef CONFIG_MCAST_TFTP
        /* Multicast TFTP.. non-MasterClients do not ACK data. */
        if (Multicast
         && (TftpState == STATE_DATA)
         && (MasterClient == 0))
                return;
#endif
        /*
         *      We will always be sending some sort of packet, so
         *      cobble together the packet headers now.
         */
        pkt = NetTxPacket + NetEthHdrSize() + IP_HDR_SIZE;

        switch (TftpState) {

        case STATE_SEND_RRQ:
                xp = pkt;
                s = (ushort *)pkt;
                *s++ = htons(TFTP_RRQ);
                pkt = (uchar *)s;
                strcpy((char *)pkt, tftp_filename);
                pkt += strlen(tftp_filename) + 1;
                strcpy((char *)pkt, "octet");
                pkt += 5 /*strlen("octet")*/ + 1;
                strcpy((char *)pkt, "timeout");
                pkt += 7 /*strlen("timeout")*/ + 1;
                sprintf((char *)pkt, "%lu", TftpTimeoutMSecs / 1000);
                debug("send option \"timeout %s\"\n", (char *)pkt);
                pkt += strlen((char *)pkt) + 1;
#ifdef CONFIG_TFTP_TSIZE
                memcpy((char *)pkt, "tsize\0000\0", 8);
                pkt += 8;
#endif
                /* try for more effic. blk size */
                pkt += sprintf((char *)pkt, "blksize%c%d%c",
                                0, TftpBlkSizeOption, 0);
#ifdef CONFIG_MCAST_TFTP
                /* Check all preconditions before even trying the option */
                if (!ProhibitMcast
                 && (Bitmap = malloc(Mapsize))
                 && eth_get_dev()->mcast) {
                        free(Bitmap);
                        Bitmap = NULL;
                        pkt += sprintf((char *)pkt, "multicast%c%c", 0, 0);
                }
#endif /* CONFIG_MCAST_TFTP */
                len = pkt - xp;
                break;

        case STATE_OACK:
#ifdef CONFIG_MCAST_TFTP
                /* My turn!  Start at where I need blocks I missed.*/
                if (Multicast)
                        TftpBlock = ext2_find_next_zero_bit(Bitmap,
                                                            (Mapsize*8), 0);
                /*..falling..*/
#endif

        case STATE_RECV_WRQ:
        case STATE_DATA:
                xp = pkt;
                s = (ushort *)pkt;
                *s++ = htons(TFTP_ACK);
                *s++ = htons(TftpBlock);
                pkt = (uchar *)s;
                len = pkt - xp;
                break;

        case STATE_TOO_LARGE:
                xp = pkt;
                s = (ushort *)pkt;
                *s++ = htons(TFTP_ERROR);
                *s++ = htons(3);
                pkt = (uchar *)s;
                strcpy((char *)pkt, "File too large");
                pkt += 14 /*strlen("File too large")*/ + 1;
                len = pkt - xp;
                break;

        case STATE_BAD_MAGIC:
                xp = pkt;
                s = (ushort *)pkt;
                *s++ = htons(TFTP_ERROR);
                *s++ = htons(2);
                pkt = (uchar *)s;
                strcpy((char *)pkt, "File has bad magic");
                pkt += 18 /*strlen("File has bad magic")*/ + 1;
                len = pkt - xp;
                break;
        }

        NetSendUDPPacket(NetServerEther, TftpRemoteIP, TftpRemotePort,
                         TftpOurPort, len);
}


static void
TftpHandler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src,
            unsigned len)
{
        ushort proto;
        ushort *s;
        int i;

        if (dest != TftpOurPort) {
#ifdef CONFIG_MCAST_TFTP
                if (Multicast
                 && (!Mcast_port || (dest != Mcast_port)))
#endif
                        return;
        }
        if (TftpState != STATE_SEND_RRQ && src != TftpRemotePort &&
            TftpState != STATE_RECV_WRQ)
                return;

        if (len < 2)
                return;
        len -= 2;
        /* warning: don't use increment (++) in ntohs() macros!! */
        s = (ushort *)pkt;
        proto = *s++;
        pkt = (uchar *)s;
        switch (ntohs(proto)) {

        case TFTP_RRQ:
        case TFTP_ACK:
                break;
        default:
                break;

#ifdef CONFIG_CMD_TFTPSRV
        case TFTP_WRQ:
                debug("Got WRQ\n");
                TftpRemoteIP = sip;
                TftpRemotePort = src;
                TftpOurPort = 1024 + (get_timer(0) % 3072);
                TftpLastBlock = 0;
                TftpBlockWrap = 0;
                TftpBlockWrapOffset = 0;
                TftpSend(); /* Send ACK(0) */
                break;
#endif

        case TFTP_OACK:
                debug("Got OACK: %s %s\n",
                        pkt,
                        pkt + strlen((char *)pkt) + 1);
                TftpState = STATE_OACK;
                TftpRemotePort = src;
                /*
                 * Check for 'blksize' option.
                 * Careful: "i" is signed, "len" is unsigned, thus
                 * something like "len-8" may give a *huge* number
                 */
                for (i = 0; i+8 < len; i++) {
                        if (strcmp((char *)pkt+i, "blksize") == 0) {
                                TftpBlkSize = (unsigned short)
                                        simple_strtoul((char *)pkt+i+8, NULL,
                                                       10);
                                debug("Blocksize ack: %s, %d\n",
                                        (char *)pkt+i+8, TftpBlkSize);
                        }
#ifdef CONFIG_TFTP_TSIZE
                        if (strcmp((char *)pkt+i, "tsize") == 0) {
                                TftpTsize = simple_strtoul((char *)pkt+i+6,
                                                           NULL, 10);
                                debug("size = %s, %d\n",
                                         (char *)pkt+i+6, TftpTsize);
                        }
#endif
                }
#ifdef CONFIG_MCAST_TFTP
                parse_multicast_oack((char *)pkt, len-1);
                if ((Multicast) && (!MasterClient))
                        TftpState = STATE_DATA; /* passive.. */
                else
#endif
                TftpSend(); /* Send ACK */
                break;
        case TFTP_DATA:
                if (len < 2)
                        return;
                len -= 2;
                TftpBlock = ntohs(*(ushort *)pkt);

                /*
                 * RFC1350 specifies that the first data packet will
                 * have sequence number 1. If we receive a sequence
                 * number of 0 this means that there was a wrap
                 * around of the (16 bit) counter.
                 */
                if (TftpBlock == 0) {
                        TftpBlockWrap++;
                        TftpBlockWrapOffset +=
                                TftpBlkSize * TFTP_SEQUENCE_SIZE;
                        printf("\n\t %lu MB received\n\t ",
                                TftpBlockWrapOffset>>20);
                }
#ifdef CONFIG_TFTP_TSIZE
                else if (TftpTsize) {
                        while (TftpNumchars <
                               NetBootFileXferSize * 50 / TftpTsize) {
                                putc('#');
                                TftpNumchars++;
                        }
                }
#endif
                else {
                        if (((TftpBlock - 1) % 10) == 0)
                                putc('#');
                        else if ((TftpBlock % (10 * HASHES_PER_LINE)) == 0)
                                puts("\n\t ");
                }

                if (TftpState == STATE_SEND_RRQ)
                        debug("Server did not acknowledge timeout option!\n");

                if (TftpState == STATE_SEND_RRQ || TftpState == STATE_OACK ||
                    TftpState == STATE_RECV_WRQ) {
                        /* first block received */
                        TftpState = STATE_DATA;
                        TftpRemotePort = src;
                        TftpLastBlock = 0;
                        TftpBlockWrap = 0;
                        TftpBlockWrapOffset = 0;

#ifdef CONFIG_MCAST_TFTP
                        if (Multicast) { /* start!=1 common if mcast */
                                TftpLastBlock = TftpBlock - 1;
                        } else
#endif
                        if (TftpBlock != 1) {   /* Assertion */
                                printf("\nTFTP error: "
                                       "First block is not block 1 (%ld)\n"
                                       "Starting again\n\n",
                                        TftpBlock);
                                NetStartAgain();
                                break;
                        }
                }

                if (TftpBlock == TftpLastBlock) {
                        /*
                         *      Same block again; ignore it.
                         */
                        break;
                }

                TftpLastBlock = TftpBlock;
                TftpTimeoutCountMax = TIMEOUT_COUNT;
                NetSetTimeout(TftpTimeoutMSecs, TftpTimeout);

                store_block(TftpBlock - 1, pkt + 2, len);

                /*
                 *      Acknowledge the block just received, which will prompt
                 *      the remote for the next one.
                 */
#ifdef CONFIG_MCAST_TFTP
                /* if I am the MasterClient, actively calculate what my next
                 * needed block is; else I'm passive; not ACKING
                 */
                if (Multicast) {
                        if (len < TftpBlkSize)  {
                                TftpEndingBlock = TftpBlock;
                        } else if (MasterClient) {
                                TftpBlock = PrevBitmapHole =
                                        ext2_find_next_zero_bit(
                                                Bitmap,
                                                (Mapsize*8),
                                                PrevBitmapHole);
                                if (TftpBlock > ((Mapsize*8) - 1)) {
                                        printf("tftpfile too big\n");
                                        /* try to double it and retry */
                                        Mapsize <<= 1;
                                        mcast_cleanup();
                                        NetStartAgain();
                                        return;
                                }
                                TftpLastBlock = TftpBlock;
                        }
                }
#endif
                TftpSend();

#ifdef CONFIG_MCAST_TFTP
                if (Multicast) {
                        if (MasterClient && (TftpBlock >= TftpEndingBlock)) {
                                puts("\nMulticast tftp done\n");
                                mcast_cleanup();
                                NetState = NETLOOP_SUCCESS;
                        }
                }
                else
#endif
                if (len < TftpBlkSize) {
                        /*
                         *      We received the whole thing.  Try to
                         *      run it.
                         */
#ifdef CONFIG_TFTP_TSIZE
                        /* Print hash marks for the last packet received */
                        while (TftpTsize && TftpNumchars < 49) {
                                putc('#');
                                TftpNumchars++;
                        }
#endif
                        puts("\ndone\n");
                        NetState = NETLOOP_SUCCESS;
                }
                break;

        case TFTP_ERROR:
                printf("\nTFTP error: '%s' (%d)\n",
                       pkt + 2, ntohs(*(ushort *)pkt));

                switch (ntohs(*(ushort *)pkt)) {
                case TFTP_ERR_FILE_NOT_FOUND:
                case TFTP_ERR_ACCESS_DENIED:
                        puts("Not retrying...\n");
                        eth_halt();
                        NetState = NETLOOP_FAIL;
                        break;
                case TFTP_ERR_UNDEFINED:
                case TFTP_ERR_DISK_FULL:
                case TFTP_ERR_UNEXPECTED_OPCODE:
                case TFTP_ERR_UNKNOWN_TRANSFER_ID:
                case TFTP_ERR_FILE_ALREADY_EXISTS:
                default:
                        puts("Starting again\n\n");
#ifdef CONFIG_MCAST_TFTP
                        mcast_cleanup();
#endif
                        NetStartAgain();
                        break;
                }
                break;
        }
}


static void
TftpTimeout(void)
{
        if (++TftpTimeoutCount > TftpTimeoutCountMax) {
                puts("\nRetry count exceeded; starting again\n");
#ifdef CONFIG_MCAST_TFTP
                mcast_cleanup();
#endif
                NetStartAgain();
        } else {
                puts("T ");
                NetSetTimeout(TftpTimeoutMSecs, TftpTimeout);
                if (TftpState != STATE_RECV_WRQ)
                        TftpSend();
        }
}


void
TftpStart(void)
{
        char *ep;             /* Environment pointer */

        /*
         * Allow the user to choose TFTP blocksize and timeout.
         * TFTP protocol has a minimal timeout of 1 second.
         */
        ep = getenv("tftpblocksize");
        if (ep != NULL)
                TftpBlkSizeOption = simple_strtol(ep, NULL, 10);

        ep = getenv("tftptimeout");
        if (ep != NULL)
                TftpTimeoutMSecs = simple_strtol(ep, NULL, 10);

        if (TftpTimeoutMSecs < 1000) {
                printf("TFTP timeout (%ld ms) too low, "
                        "set minimum = 1000 ms\n",
                        TftpTimeoutMSecs);
                TftpTimeoutMSecs = 1000;
        }

        debug("TFTP blocksize = %i, timeout = %ld ms\n",
                TftpBlkSizeOption, TftpTimeoutMSecs);

        TftpRemoteIP = NetServerIP;
        if (BootFile[0] == '\0') {
                sprintf(default_filename, "%02lX%02lX%02lX%02lX.img",
                        NetOurIP & 0xFF,
                        (NetOurIP >>  8) & 0xFF,
                        (NetOurIP >> 16) & 0xFF,
                        (NetOurIP >> 24) & 0xFF);

                strncpy(tftp_filename, default_filename, MAX_LEN);
                tftp_filename[MAX_LEN-1] = 0;

                printf("*** Warning: no boot file name; using '%s'\n",
                        tftp_filename);
        } else {
                char *p = strchr(BootFile, ':');

                if (p == NULL) {
                        strncpy(tftp_filename, BootFile, MAX_LEN);
                        tftp_filename[MAX_LEN-1] = 0;
                } else {
                        TftpRemoteIP = string_to_ip(BootFile);
                        strncpy(tftp_filename, p + 1, MAX_LEN);
                        tftp_filename[MAX_LEN-1] = 0;
                }
        }

#if defined(CONFIG_NET_MULTI)
        printf("Using %s device\n", eth_get_name());
#endif
        printf("TFTP from server %pI4"
                "; our IP address is %pI4", &TftpRemoteIP, &NetOurIP);

        /* Check if we need to send across this subnet */
        if (NetOurGatewayIP && NetOurSubnetMask) {
                IPaddr_t OurNet = NetOurIP    & NetOurSubnetMask;
                IPaddr_t RemoteNet      = TftpRemoteIP & NetOurSubnetMask;

                if (OurNet != RemoteNet)
                        printf("; sending through gateway %pI4",
                               &NetOurGatewayIP);
        }
        putc('\n');

        printf("Filename '%s'.", tftp_filename);

        if (NetBootFileSize) {
                printf(" Size is 0x%x Bytes = ", NetBootFileSize<<9);
                print_size(NetBootFileSize<<9, "");
        }

        putc('\n');

        printf("Load address: 0x%lx\n", load_addr);

        puts("Loading: *\b");

        TftpTimeoutCountMax = TftpRRQTimeoutCountMax;

        NetSetTimeout(TftpTimeoutMSecs, TftpTimeout);
        NetSetHandler(TftpHandler);

        TftpRemotePort = WELL_KNOWN_PORT;
        TftpTimeoutCount = 0;
        TftpState = STATE_SEND_RRQ;
        /* Use a pseudo-random port unless a specific port is set */
        TftpOurPort = 1024 + (get_timer(0) % 3072);

#ifdef CONFIG_TFTP_PORT
        ep = getenv("tftpdstp");
        if (ep != NULL)
                TftpRemotePort = simple_strtol(ep, NULL, 10);
        ep = getenv("tftpsrcp");
        if (ep != NULL)
                TftpOurPort = simple_strtol(ep, NULL, 10);
#endif
        TftpBlock = 0;

        /* zero out server ether in case the server ip has changed */
        memset(NetServerEther, 0, 6);
        /* Revert TftpBlkSize to dflt */
        TftpBlkSize = TFTP_BLOCK_SIZE;
#ifdef CONFIG_MCAST_TFTP
        mcast_cleanup();
#endif
#ifdef CONFIG_TFTP_TSIZE
        TftpTsize = 0;
        TftpNumchars = 0;
#endif

        TftpSend();
}

#ifdef CONFIG_CMD_TFTPSRV
void
TftpStartServer(void)
{
        tftp_filename[0] = 0;

#if defined(CONFIG_NET_MULTI)
        printf("Using %s device\n", eth_get_name());
#endif
        printf("Listening for TFTP transfer on %pI4\n", &NetOurIP);
        printf("Load address: 0x%lx\n", load_addr);

        puts("Loading: *\b");

        TftpTimeoutCountMax = TIMEOUT_COUNT;
        TftpTimeoutCount = 0;
        TftpTimeoutMSecs = TIMEOUT;
        NetSetTimeout(TftpTimeoutMSecs, TftpTimeout);

        /* Revert TftpBlkSize to dflt */
        TftpBlkSize = TFTP_BLOCK_SIZE;
        TftpBlock = 0;
        TftpOurPort = WELL_KNOWN_PORT;

#ifdef CONFIG_TFTP_TSIZE
        TftpTsize = 0;
        TftpNumchars = 0;
#endif

        TftpState = STATE_RECV_WRQ;
        NetSetHandler(TftpHandler);
}
#endif /* CONFIG_CMD_TFTPSRV */

#ifdef CONFIG_MCAST_TFTP
/* Credits: atftp project.
 */

/* pick up BcastAddr, Port, and whether I am [now] the master-client. *
 * Frame:
 *    +-------+-----------+---+-------~~-------+---+
 *    |  opc  | multicast | 0 | addr, port, mc | 0 |
 *    +-------+-----------+---+-------~~-------+---+
 * The multicast addr/port becomes what I listen to, and if 'mc' is '1' then
 * I am the new master-client so must send ACKs to DataBlocks.  If I am not
 * master-client, I'm a passive client, gathering what DataBlocks I may and
 * making note of which ones I got in my bitmask.
 * In theory, I never go from master->passive..
 * .. this comes in with pkt already pointing just past opc
 */
static void parse_multicast_oack(char *pkt, int len)
{
        int i;
        IPaddr_t addr;
        char *mc_adr, *port,  *mc;

        mc_adr = port = mc = NULL;
        /* march along looking for 'multicast\0', which has to start at least
         * 14 bytes back from the end.
         */
        for (i = 0; i < len-14; i++)
                if (strcmp(pkt+i, "multicast") == 0)
                        break;
        if (i >= (len-14)) /* non-Multicast OACK, ign. */
                return;

        i += 10; /* strlen multicast */
        mc_adr = pkt+i;
        for (; i < len; i++) {
                if (*(pkt+i) == ',') {
                        *(pkt+i) = '\0';
                        if (port) {
                                mc = pkt+i+1;
                                break;
                        } else {
                                port = pkt+i+1;
                        }
                }
        }
        if (!port || !mc_adr || !mc)
                return;
        if (Multicast && MasterClient) {
                printf("I got a OACK as master Client, WRONG!\n");
                return;
        }
        /* ..I now accept packets destined for this MCAST addr, port */
        if (!Multicast) {
                if (Bitmap) {
                        printf("Internal failure! no mcast.\n");
                        free(Bitmap);
                        Bitmap = NULL;
                        ProhibitMcast = 1;
                        return ;
                }
                /* I malloc instead of pre-declare; so that if the file ends
                 * up being too big for this bitmap I can retry
                 */
                Bitmap = malloc(Mapsize);
                if (!Bitmap) {
                        printf("No Bitmap, no multicast. Sorry.\n");
                        ProhibitMcast = 1;
                        return;
                }
                memset(Bitmap, 0, Mapsize);
                PrevBitmapHole = 0;
                Multicast = 1;
        }
        addr = string_to_ip(mc_adr);
        if (Mcast_addr != addr) {
                if (Mcast_addr)
                        eth_mcast_join(Mcast_addr, 0);
                Mcast_addr = addr;
                if (eth_mcast_join(Mcast_addr, 1)) {
                        printf("Fail to set mcast, revert to TFTP\n");
                        ProhibitMcast = 1;
                        mcast_cleanup();
                        NetStartAgain();
                }
        }
        MasterClient = (unsigned char)simple_strtoul((char *)mc, NULL, 10);
        Mcast_port = (unsigned short)simple_strtoul(port, NULL, 10);
        printf("Multicast: %s:%d [%d]\n", mc_adr, Mcast_port, MasterClient);
        return;
}

#endif /* Multicast TFTP */