summaryrefslogtreecommitdiff
path: root/net/tftp.c
blob: 6386740b1d684d904f4433235f4b061b62cc4fcc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
/*
 * Copyright 1994, 1995, 2000 Neil Russell.
 * (See License)
 * Copyright 2000, 2001 DENX Software Engineering, Wolfgang Denk, wd@denx.de
 */

#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

/* 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_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)
		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_WRQ:
	case TFTP_ACK:
		break;
	default:
		break;

	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) {
			/* 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);

		/*
		 *	Acknoledge 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);
		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_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 */