/*
   * 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"
  #ifdef CONFIG_SYS_DIRECT_FLASH_TFTP
  #include <flash.h>
  #endif
  
  /* 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;
  static ulong time_start;   /* Record time we started tftp */
  
  /*
   * 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
  #ifdef CONFIG_CMD_TFTPPUT
  static int	TftpWriting;	/* 1 if writing, else 0 */
  static int	TftpFinalBlock;	/* 1 if we have sent the last block */
  #else
  #define TftpWriting	0
  #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
  #define STATE_SEND_WRQ	7
  
  /* 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];
  
  /* 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;
  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(int 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);
  			net_set_state(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;
  }
  
  /* Clear our state ready for a new transfer */
  static void new_transfer(void)
  {
  	TftpLastBlock = 0;
  	TftpBlockWrap = 0;
  	TftpBlockWrapOffset = 0;
  #ifdef CONFIG_CMD_TFTPPUT
  	TftpFinalBlock = 0;
  #endif
  }
  
  #ifdef CONFIG_CMD_TFTPPUT
  /**
   * Load the next block from memory to be sent over tftp.
   *
   * @param block	Block number to send
   * @param dst	Destination buffer for data
   * @param len	Number of bytes in block (this one and every other)
   * @return number of bytes loaded
   */
  static int load_block(unsigned block, uchar *dst, unsigned len)
  {
  	/* We may want to get the final block from the previous set */
  	ulong offset = ((int)block - 1) * len + TftpBlockWrapOffset;
  	ulong tosend = len;
  
  	tosend = min(NetBootFileXferSize - offset, tosend);
  	(void)memcpy(dst, (void *)(save_addr + offset), tosend);
  	debug("%s: block=%d, offset=%ld, len=%d, tosend=%ld
  ", __func__,
  		block, offset, len, tosend);
  	return tosend;
  }
  #endif
  
  static void TftpSend(void);
  static void TftpTimeout(void);
  
  /**********************************************************************/
  
  static void show_block_marker(void)
  {
  #ifdef CONFIG_TFTP_TSIZE
  	if (TftpTsize) {
  		ulong pos = TftpBlock * TftpBlkSize + TftpBlockWrapOffset;
  
  		while (TftpNumchars < pos * 50 / TftpTsize) {
  			putc('#');
  			TftpNumchars++;
  		}
  	} else
  #endif
  	{
  		if (((TftpBlock - 1) % 10) == 0)
  			putc('#');
  		else if ((TftpBlock % (10 * HASHES_PER_LINE)) == 0)
  			puts("
  \t ");
  	}
  }
  
  /**
   * restart the current transfer due to an error
   *
   * @param msg	Message to print for user
   */
  static void restart(const char *msg)
  {
  	printf("
  %s; starting again
  ", msg);
  #ifdef CONFIG_MCAST_TFTP
  	mcast_cleanup();
  #endif
  	NetStartAgain();
  }
  
  /*
   * Check if the block number has wrapped, and update progress
   *
   * TODO: The egregious use of global variables in this file should be tidied.
   */
  static void update_block_number(void)
  {
  	/*
  	 * 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 && TftpLastBlock != 0) {
  		TftpBlockWrap++;
  		TftpBlockWrapOffset += TftpBlkSize * TFTP_SEQUENCE_SIZE;
  		TftpTimeoutCount = 0; /* we've done well, reset thhe timeout */
  	} else {
  		show_block_marker();
  	}
  }
  
  /* The TFTP get or put is complete */
  static void tftp_complete(void)
  {
  #ifdef CONFIG_TFTP_TSIZE
  	/* Print hash marks for the last packet received */
  	while (TftpTsize && TftpNumchars < 49) {
  		putc('#');
  		TftpNumchars++;
  	}
  	puts("  ");
  	print_size(TftpTsize, "");
  #endif
  	time_start = get_timer(time_start);
  	if (time_start > 0) {
  		puts("
  \t ");	/* Line up with "Loading: " */
  		print_size(NetBootFileXferSize /
  			time_start * 1000, "/s");
  	}
  	puts("
  done
  ");
  	net_set_state(NETLOOP_SUCCESS);
  }
  
  static void
  TftpSend(void)
  {
  	uchar *pkt;
  	uchar *xp;
  	int len = 0;
  	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_UDP_HDR_SIZE;
  
  	switch (TftpState) {
  	case STATE_SEND_RRQ:
  	case STATE_SEND_WRQ:
  		xp = pkt;
  		s = (ushort *)pkt;
  #ifdef CONFIG_CMD_TFTPPUT
  		*s++ = htons(TftpState == STATE_SEND_RRQ ? TFTP_RRQ :
  			TFTP_WRQ);
  #else
  		*s++ = htons(TFTP_RRQ);
  #endif
  		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\"
  ", (char *)pkt);
  		pkt += strlen((char *)pkt) + 1;
  #ifdef CONFIG_TFTP_TSIZE
  		pkt += sprintf((char *)pkt, "tsize%c%lu%c",
  				0, NetBootFileXferSize, 0);
  #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);
  			if (Bitmap && 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[0] = htons(TFTP_ACK);
  		s[1] = htons(TftpBlock);
  		pkt = (uchar *)(s + 2);
  #ifdef CONFIG_CMD_TFTPPUT
  		if (TftpWriting) {
  			int toload = TftpBlkSize;
  			int loaded = load_block(TftpBlock, pkt, toload);
  
  			s[0] = htons(TFTP_DATA);
  			pkt += loaded;
  			TftpFinalBlock = (loaded < toload);
  		}
  #endif
  		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);
  }
  
  #ifdef CONFIG_CMD_TFTPPUT
  static void icmp_handler(unsigned type, unsigned code, unsigned dest,
  			 IPaddr_t sip, unsigned src, uchar *pkt, unsigned len)
  {
  	if (type == ICMP_NOT_REACH && code == ICMP_NOT_REACH_PORT) {
  		/* Oh dear the other end has gone away */
  		restart("TFTP server died");
  	}
  }
  #endif
  
  static void
  TftpHandler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src,
  	    unsigned len)
  {
  	__be16 proto;
  	__be16 *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 && TftpState != STATE_SEND_WRQ)
  		return;
  
  	if (len < 2)
  		return;
  	len -= 2;
  	/* warning: don't use increment (++) in ntohs() macros!! */
  	s = (__be16 *)pkt;
  	proto = *s++;
  	pkt = (uchar *)s;
  	switch (ntohs(proto)) {
  
  	case TFTP_RRQ:
  		break;
  
  	case TFTP_ACK:
  #ifdef CONFIG_CMD_TFTPPUT
  		if (TftpWriting) {
  			if (TftpFinalBlock) {
  				tftp_complete();
  			} else {
  				/*
  				 * Move to the next block. We want our block
  				 * count to wrap just like the other end!
  				 */
  				int block = ntohs(*s);
  				int ack_ok = (TftpBlock == block);
  
  				TftpBlock = (unsigned short)(block + 1);
  				update_block_number();
  				if (ack_ok)
  					TftpSend(); /* Send next data block */
  			}
  		}
  #endif
  		break;
  
  	default:
  		break;
  
  #ifdef CONFIG_CMD_TFTPSRV
  	case TFTP_WRQ:
  		debug("Got WRQ
  ");
  		TftpRemoteIP = sip;
  		TftpRemotePort = src;
  		TftpOurPort = 1024 + (get_timer(0) % 3072);
  		new_transfer();
  		TftpSend(); /* Send ACK(0) */
  		break;
  #endif
  
  	case TFTP_OACK:
  		debug("Got OACK: %s %s
  ",
  			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
  ",
  					(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
  ",
  					 (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
  #ifdef CONFIG_CMD_TFTPPUT
  		if (TftpWriting) {
  			/* Get ready to send the first block */
  			TftpState = STATE_DATA;
  			TftpBlock++;
  		}
  #endif
  		TftpSend(); /* Send ACK or first data block */
  		break;
  	case TFTP_DATA:
  		if (len < 2)
  			return;
  		len -= 2;
  		TftpBlock = ntohs(*(__be16 *)pkt);
  
  		update_block_number();
  
  		if (TftpState == STATE_SEND_RRQ)
  			debug("Server did not acknowledge timeout option!
  ");
  
  		if (TftpState == STATE_SEND_RRQ || TftpState == STATE_OACK ||
  		    TftpState == STATE_RECV_WRQ) {
  			/* first block received */
  			TftpState = STATE_DATA;
  			TftpRemotePort = src;
  			new_transfer();
  
  #ifdef CONFIG_MCAST_TFTP
  			if (Multicast) { /* start!=1 common if mcast */
  				TftpLastBlock = TftpBlock - 1;
  			} else
  #endif
  			if (TftpBlock != 1) {	/* Assertion */
  				printf("
  TFTP error: "
  				       "First block is not block 1 (%ld)
  "
  				       "Starting again
  
  ",
  					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
  ");
  					/* 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("
  Multicast tftp done
  ");
  				mcast_cleanup();
  				net_set_state(NETLOOP_SUCCESS);
  			}
  		} else
  #endif
  		if (len < TftpBlkSize)
  			tftp_complete();
  		break;
  
  	case TFTP_ERROR:
  		printf("
  TFTP error: '%s' (%d)
  ",
  		       pkt + 2, ntohs(*(__be16 *)pkt));
  
  		switch (ntohs(*(__be16 *)pkt)) {
  		case TFTP_ERR_FILE_NOT_FOUND:
  		case TFTP_ERR_ACCESS_DENIED:
  			puts("Not retrying...
  ");
  			eth_halt();
  			net_set_state(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
  
  ");
  #ifdef CONFIG_MCAST_TFTP
  			mcast_cleanup();
  #endif
  			NetStartAgain();
  			break;
  		}
  		break;
  	}
  }
  
  
  static void
  TftpTimeout(void)
  {
  	if (++TftpTimeoutCount > TftpTimeoutCountMax) {
  		restart("Retry count exceeded");
  	} else {
  		puts("T ");
  		NetSetTimeout(TftpTimeoutMSecs, TftpTimeout);
  		if (TftpState != STATE_RECV_WRQ)
  			TftpSend();
  	}
  }
  
  
  void TftpStart(enum proto_t protocol)
  {
  	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
  ",
  			TftpTimeoutMSecs);
  		TftpTimeoutMSecs = 1000;
  	}
  
  	debug("TFTP blocksize = %i, timeout = %ld ms
  ",
  		TftpBlkSizeOption, TftpTimeoutMSecs);
  
  	TftpRemoteIP = NetServerIP;
  	if (BootFile[0] == '\0') {
  		sprintf(default_filename, "%02X%02X%02X%02X.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'
  ",
  			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;
  		}
  	}
  
  	printf("Using %s device
  ", eth_get_name());
  	printf("TFTP %s server %pI4; our IP address is %pI4",
  #ifdef CONFIG_CMD_TFTPPUT
  	       protocol == TFTPPUT ? "to" : "from",
  #else
  		"from",
  #endif
  		&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('
  ');
  
  	printf("Filename '%s'.", tftp_filename);
  
  	if (NetBootFileSize) {
  		printf(" Size is 0x%x Bytes = ", NetBootFileSize<<9);
  		print_size(NetBootFileSize<<9, "");
  	}
  
  	putc('
  ');
  #ifdef CONFIG_CMD_TFTPPUT
  	TftpWriting = (protocol == TFTPPUT);
  	if (TftpWriting) {
  		printf("Save address: 0x%lx
  ", save_addr);
  		printf("Save size:    0x%lx
  ", save_size);
  		NetBootFileXferSize = save_size;
  		puts("Saving: *\b");
  		TftpState = STATE_SEND_WRQ;
  		new_transfer();
  	} else
  #endif
  	{
  		printf("Load address: 0x%lx
  ", load_addr);
  		puts("Loading: *\b");
  		TftpState = STATE_SEND_RRQ;
  	}
  
  	time_start = get_timer(0);
  	TftpTimeoutCountMax = TftpRRQTimeoutCountMax;
  
  	NetSetTimeout(TftpTimeoutMSecs, TftpTimeout);
  	net_set_udp_handler(TftpHandler);
  #ifdef CONFIG_CMD_TFTPPUT
  	net_set_icmp_handler(icmp_handler);
  #endif
  	TftpRemotePort = WELL_KNOWN_PORT;
  	TftpTimeoutCount = 0;
  	/* 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;
  
  	printf("Using %s device
  ", eth_get_name());
  	printf("Listening for TFTP transfer on %pI4
  ", &NetOurIP);
  	printf("Load address: 0x%lx
  ", 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;
  	net_set_udp_handler(TftpHandler);
  
  	/* zero out server ether in case the server ip has changed */
  	memset(NetServerEther, 0, 6);
  }
  #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!
  ");
  		return;
  	}
  	/* ..I now accept packets destined for this MCAST addr, port */
  	if (!Multicast) {
  		if (Bitmap) {
  			printf("Internal failure! no mcast.
  ");
  			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.
  ");
  			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
  ");
  			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]
  ", mc_adr, Mcast_port, MasterClient);
  	return;
  }
  
  #endif /* Multicast TFTP */