summaryrefslogtreecommitdiff
path: root/net/tftp.c
blob: 03079ded34e3050dea4dcd5f6840112c628aab0f (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
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
/*
 * 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 <efi_loader.h>
#include <env.h>
#include <image.h>
#include <lmb.h>
#include <log.h>
#include <mapmem.h>
#include <net.h>
#include <net/tftp.h>
#include "bootp.h"
#ifdef CONFIG_SYS_DIRECT_FLASH_TFTP
#include <flash.h>
#endif

DECLARE_GLOBAL_DATA_PTR;

/* 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 timeout_ms = TIMEOUT;
static int timeout_count_max = 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. tftp_timeout_ms specifies the number of milliseconds to
 * wait for the server to respond to initial connection. Second global,
 * tftp_timeout_count_max, gives the number of such connection retries.
 * tftp_timeout_count_max must be non-negative and tftp_timeout_ms 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 tftp_timeout_ms = TIMEOUT;
int tftp_timeout_count_max = 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,
	TFTP_ERR_OPTION_NEGOTIATION = 8,
};

static struct in_addr tftp_remote_ip;
/* The UDP port at their end */
static int	tftp_remote_port;
/* The UDP port at our end */
static int	tftp_our_port;
static int	timeout_count;
/* packet sequence number */
static ulong	tftp_cur_block;
/* last packet sequence number received */
static ulong	tftp_prev_block;
/* count of sequence number wraparounds */
static ulong	tftp_block_wrap;
/* memory offset due to wrapping */
static ulong	tftp_block_wrap_offset;
static int	tftp_state;
static ulong	tftp_load_addr;
#ifdef CONFIG_LMB
static ulong	tftp_load_size;
#endif
#ifdef CONFIG_TFTP_TSIZE
/* The file size reported by the server */
static int	tftp_tsize;
/* The number of hashes we printed */
static short	tftp_tsize_num_hash;
#endif
/* The window size negotiated */
static ushort	tftp_windowsize;
/* Next block to send ack to */
static ushort	tftp_next_ack;
/* Last nack block we send */
static ushort	tftp_last_nack;
#ifdef CONFIG_CMD_TFTPPUT
/* 1 if writing, else 0 */
static int	tftp_put_active;
/* 1 if we have sent the last block */
static int	tftp_put_final_block_sent;
#else
#define tftp_put_active	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
#define STATE_INVALID_OPTION	8

/* 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)
 */

/* When windowsize is defined to 1,
 * tftp behaves the same way as it was
 * never declared
 */
#ifdef CONFIG_TFTP_WINDOWSIZE
#define TFTP_WINDOWSIZE CONFIG_TFTP_WINDOWSIZE
#else
#define TFTP_WINDOWSIZE 1
#endif

static unsigned short tftp_block_size = TFTP_BLOCK_SIZE;
static unsigned short tftp_block_size_option = CONFIG_TFTP_BLOCKSIZE;
static unsigned short tftp_window_size_option = TFTP_WINDOWSIZE;

static inline int store_block(int block, uchar *src, unsigned int len)
{
	ulong offset = block * tftp_block_size + tftp_block_wrap_offset -
			tftp_block_size;
	ulong newsize = offset + len;
	ulong store_addr = tftp_load_addr + offset;
#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 (store_addr >= flash_info[i].start[0]) {
			rc = 1;
			break;
		}
	}

	if (rc) { /* Flash is destination for this packet */
		rc = flash_write((char *)src, store_addr, len);
		if (rc) {
			flash_perror(rc);
			return rc;
		}
	} else
#endif /* CONFIG_SYS_DIRECT_FLASH_TFTP */
	{
		void *ptr;

#ifdef CONFIG_LMB
		ulong end_addr = tftp_load_addr + tftp_load_size;

		if (!end_addr)
			end_addr = ULONG_MAX;

		if (store_addr < tftp_load_addr ||
		    store_addr + len > end_addr) {
			puts("\nTFTP error: ");
			puts("trying to overwrite reserved memory...\n");
			return -1;
		}
#endif
		ptr = map_sysmem(store_addr, len);
		memcpy(ptr, src, len);
		unmap_sysmem(ptr);
	}

	if (net_boot_file_size < newsize)
		net_boot_file_size = newsize;

	return 0;
}

/* Clear our state ready for a new transfer */
static void new_transfer(void)
{
	tftp_prev_block = 0;
	tftp_block_wrap = 0;
	tftp_block_wrap_offset = 0;
#ifdef CONFIG_CMD_TFTPPUT
	tftp_put_final_block_sent = 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 = block * tftp_block_size + tftp_block_wrap_offset -
		       tftp_block_size;
	ulong tosend = len;

	tosend = min(net_boot_file_size - offset, tosend);
	(void)memcpy(dst, (void *)(image_save_addr + offset), tosend);
	debug("%s: block=%u, offset=%lu, len=%u, tosend=%lu\n", __func__,
	      block, offset, len, tosend);
	return tosend;
}
#endif

static void tftp_send(void);
static void tftp_timeout_handler(void);

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

static void show_block_marker(void)
{
	ulong pos;

#ifdef CONFIG_TFTP_TSIZE
	if (tftp_tsize) {
		pos = tftp_cur_block * tftp_block_size +
			tftp_block_wrap_offset;
		if (pos > tftp_tsize)
			pos = tftp_tsize;

		while (tftp_tsize_num_hash < pos * 50 / tftp_tsize) {
			putc('#');
			tftp_tsize_num_hash++;
		}
	} else
#endif
	{
		pos = (tftp_cur_block - 1) +
			(tftp_block_wrap * TFTP_SEQUENCE_SIZE);
		if ((pos % 10) == 0)
			putc('#');
		else if (((pos + 1) % (10 * HASHES_PER_LINE)) == 0)
			puts("\n\t ");
	}
}

/**
 * restart the current transfer due to an error
 *
 * @param msg	Message to print for user
 */
static void restart(const char *msg)
{
	printf("\n%s; starting again\n", msg);
	net_start_again();
}

/*
 * 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 (tftp_cur_block == 0 && tftp_prev_block != 0) {
		tftp_block_wrap++;
		tftp_block_wrap_offset += tftp_block_size * TFTP_SEQUENCE_SIZE;
		timeout_count = 0; /* we've done well, reset the timeout */
	}
	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 (tftp_tsize && tftp_tsize_num_hash < 49) {
		putc('#');
		tftp_tsize_num_hash++;
	}
	puts("  ");
	print_size(tftp_tsize, "");
#endif
	time_start = get_timer(time_start);
	if (time_start > 0) {
		puts("\n\t ");	/* Line up with "Loading: " */
		print_size(net_boot_file_size /
			time_start * 1000, "/s");
	}
	puts("\ndone\n");
	if (IS_ENABLED(CONFIG_CMD_BOOTEFI)) {
		if (!tftp_put_active)
			efi_set_bootdev("Net", "", tftp_filename,
					map_sysmem(tftp_load_addr, 0),
					net_boot_file_size);
	}
	net_set_state(NETLOOP_SUCCESS);
}

static void tftp_send(void)
{
	uchar *pkt;
	uchar *xp;
	int len = 0;
	ushort *s;
	bool err_pkt = false;

	/*
	 *	We will always be sending some sort of packet, so
	 *	cobble together the packet headers now.
	 */
	pkt = net_tx_packet + net_eth_hdr_size() + IP_UDP_HDR_SIZE;

	switch (tftp_state) {
	case STATE_SEND_RRQ:
	case STATE_SEND_WRQ:
		xp = pkt;
		s = (ushort *)pkt;
#ifdef CONFIG_CMD_TFTPPUT
		*s++ = htons(tftp_state == 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", timeout_ms / 1000);
		debug("send option \"timeout %s\"\n", (char *)pkt);
		pkt += strlen((char *)pkt) + 1;
#ifdef CONFIG_TFTP_TSIZE
		pkt += sprintf((char *)pkt, "tsize%c%u%c",
				0, net_boot_file_size, 0);
#endif
		/* try for more effic. blk size */
		pkt += sprintf((char *)pkt, "blksize%c%d%c",
				0, tftp_block_size_option, 0);

		/* try for more effic. window size.
		 * Implemented only for tftp get.
		 * Don't bother sending if it's 1
		 */
		if (tftp_state == STATE_SEND_RRQ && tftp_window_size_option > 1)
			pkt += sprintf((char *)pkt, "windowsize%c%d%c",
					0, tftp_window_size_option, 0);
		len = pkt - xp;
		break;

	case STATE_OACK:

	case STATE_RECV_WRQ:
	case STATE_DATA:
		xp = pkt;
		s = (ushort *)pkt;
		s[0] = htons(TFTP_ACK);
		s[1] = htons(tftp_cur_block);
		pkt = (uchar *)(s + 2);
#ifdef CONFIG_CMD_TFTPPUT
		if (tftp_put_active) {
			int toload = tftp_block_size;
			int loaded = load_block(tftp_cur_block, pkt, toload);

			s[0] = htons(TFTP_DATA);
			pkt += loaded;
			tftp_put_final_block_sent = (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;
		err_pkt = true;
		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;
		err_pkt = true;
		break;

	case STATE_INVALID_OPTION:
		xp = pkt;
		s = (ushort *)pkt;
		*s++ = htons(TFTP_ERROR);
		*s++ = htons(TFTP_ERR_OPTION_NEGOTIATION);
		pkt = (uchar *)s;
		strcpy((char *)pkt, "Option Negotiation Failed");
		/* strlen("Option Negotiation Failed") + NULL*/
		pkt += 25 + 1;
		len = pkt - xp;
		err_pkt = true;
		break;
	}

	net_send_udp_packet(net_server_ethaddr, tftp_remote_ip,
			    tftp_remote_port, tftp_our_port, len);

	if (err_pkt)
		net_set_state(NETLOOP_FAIL);
}

#ifdef CONFIG_CMD_TFTPPUT
static void icmp_handler(unsigned type, unsigned code, unsigned dest,
			 struct in_addr 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 tftp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
			 unsigned src, unsigned len)
{
	__be16 proto;
	__be16 *s;
	int i;
	u16 timeout_val_rcvd;

	if (dest != tftp_our_port) {
			return;
	}
	if (tftp_state != STATE_SEND_RRQ && src != tftp_remote_port &&
	    tftp_state != STATE_RECV_WRQ && tftp_state != 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 (tftp_put_active) {
			if (tftp_put_final_block_sent) {
				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 = (tftp_cur_block == block);

				tftp_prev_block = tftp_cur_block;
				tftp_cur_block = (unsigned short)(block + 1);
				update_block_number();
				if (ack_ok)
					tftp_send(); /* Send next data block */
			}
		}
#endif
		break;

	default:
		break;

#ifdef CONFIG_CMD_TFTPSRV
	case TFTP_WRQ:
		debug("Got WRQ\n");
		tftp_remote_ip = sip;
		tftp_remote_port = src;
		tftp_our_port = 1024 + (get_timer(0) % 3072);
		new_transfer();
		tftp_send(); /* Send ACK(0) */
		break;
#endif

	case TFTP_OACK:
		debug("Got OACK: ");
		for (i = 0; i < len; i++) {
			if (pkt[i] == '\0')
				debug(" ");
			else
				debug("%c", pkt[i]);
		}
		debug("\n");
		tftp_state = STATE_OACK;
		tftp_remote_port = 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 (strcasecmp((char *)pkt + i, "blksize") == 0) {
				tftp_block_size = (unsigned short)
					simple_strtoul((char *)pkt + i + 8,
						       NULL, 10);
				debug("Blocksize oack: %s, %d\n",
				      (char *)pkt + i + 8, tftp_block_size);
				if (tftp_block_size > tftp_block_size_option) {
					printf("Invalid blk size(=%d)\n",
					       tftp_block_size);
					tftp_state = STATE_INVALID_OPTION;
				}
			}
			if (strcasecmp((char *)pkt + i, "timeout") == 0) {
				timeout_val_rcvd = (unsigned short)
					simple_strtoul((char *)pkt + i + 8,
						       NULL, 10);
				debug("Timeout oack: %s, %d\n",
				      (char *)pkt + i + 8, timeout_val_rcvd);
				if (timeout_val_rcvd != (timeout_ms / 1000)) {
					printf("Invalid timeout val(=%d s)\n",
					       timeout_val_rcvd);
					tftp_state = STATE_INVALID_OPTION;
				}
			}
#ifdef CONFIG_TFTP_TSIZE
			if (strcasecmp((char *)pkt + i, "tsize") == 0) {
				tftp_tsize = simple_strtoul((char *)pkt + i + 6,
							   NULL, 10);
				debug("size = %s, %d\n",
				      (char *)pkt + i + 6, tftp_tsize);
			}
#endif
			if (strcasecmp((char *)pkt + i,  "windowsize") == 0) {
				tftp_windowsize =
					simple_strtoul((char *)pkt + i + 11,
						       NULL, 10);
				debug("windowsize = %s, %d\n",
				      (char *)pkt + i + 11, tftp_windowsize);
			}
		}

		tftp_next_ack = tftp_windowsize;

#ifdef CONFIG_CMD_TFTPPUT
		if (tftp_put_active && tftp_state == STATE_OACK) {
			/* Get ready to send the first block */
			tftp_state = STATE_DATA;
			tftp_cur_block++;
		}
#endif
		tftp_send(); /* Send ACK or first data block */
		break;
	case TFTP_DATA:
		if (len < 2)
			return;
		len -= 2;

		if (ntohs(*(__be16 *)pkt) != (ushort)(tftp_cur_block + 1)) {
			debug("Received unexpected block: %d, expected: %d\n",
			      ntohs(*(__be16 *)pkt),
			      (ushort)(tftp_cur_block + 1));
			/*
			 * If one packet is dropped most likely
			 * all other buffers in the window
			 * that will arrive will cause a sending NACK.
			 * This just overwellms the server, let's just send one.
			 */
			if (tftp_last_nack != tftp_cur_block) {
				tftp_send();
				tftp_last_nack = tftp_cur_block;
				tftp_next_ack = (ushort)(tftp_cur_block +
							 tftp_windowsize);
			}
			break;
		}

		tftp_cur_block++;
		tftp_cur_block %= TFTP_SEQUENCE_SIZE;

		if (tftp_state == STATE_SEND_RRQ) {
			debug("Server did not acknowledge any options!\n");
			tftp_next_ack = tftp_windowsize;
		}

		if (tftp_state == STATE_SEND_RRQ || tftp_state == STATE_OACK ||
		    tftp_state == STATE_RECV_WRQ) {
			/* first block received */
			tftp_state = STATE_DATA;
			tftp_remote_port = src;
			new_transfer();

			if (tftp_cur_block != 1) {	/* Assertion */
				puts("\nTFTP error: ");
				printf("First block is not block 1 (%ld)\n",
				       tftp_cur_block);
				puts("Starting again\n\n");
				net_start_again();
				break;
			}
		}

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

		update_block_number();
		tftp_prev_block = tftp_cur_block;
		timeout_count_max = tftp_timeout_count_max;
		net_set_timeout_handler(timeout_ms, tftp_timeout_handler);

		if (store_block(tftp_cur_block, pkt + 2, len)) {
			eth_halt();
			net_set_state(NETLOOP_FAIL);
			break;
		}

		/*
		 *	Acknowledge the block just received, which will prompt
		 *	the remote for the next one.
		 */
		if (tftp_cur_block == tftp_next_ack) {
			tftp_send();
			tftp_next_ack += tftp_windowsize;
		}

		if (len < tftp_block_size) {
			tftp_send();
			tftp_complete();
		}
		break;

	case TFTP_ERROR:
		printf("\nTFTP error: '%s' (%d)\n",
		       pkt + 2, ntohs(*(__be16 *)pkt));

		switch (ntohs(*(__be16 *)pkt)) {
		case TFTP_ERR_FILE_NOT_FOUND:
		case TFTP_ERR_ACCESS_DENIED:
			puts("Not retrying...\n");
			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\n\n");
			net_start_again();
			break;
		}
		break;
	}
}


static void tftp_timeout_handler(void)
{
	if (++timeout_count > timeout_count_max) {
		restart("Retry count exceeded");
	} else {
		puts("T ");
		net_set_timeout_handler(timeout_ms, tftp_timeout_handler);
		if (tftp_state != STATE_RECV_WRQ)
			tftp_send();
	}
}

/* Initialize tftp_load_addr and tftp_load_size from image_load_addr and lmb */
static int tftp_init_load_addr(void)
{
#ifdef CONFIG_LMB
	struct lmb lmb;
	phys_size_t max_size;

	lmb_init_and_reserve(&lmb, gd->bd, (void *)gd->fdt_blob);

	max_size = lmb_get_free_size(&lmb, image_load_addr);
	if (!max_size)
		return -1;

	tftp_load_size = max_size;
#endif
	tftp_load_addr = image_load_addr;
	return 0;
}

void tftp_start(enum proto_t protocol)
{
#if CONFIG_NET_TFTP_VARS
	char *ep;             /* Environment pointer */

	/*
	 * Allow the user to choose TFTP blocksize and timeout.
	 * TFTP protocol has a minimal timeout of 1 second.
	 */

	ep = env_get("tftpblocksize");
	if (ep != NULL)
		tftp_block_size_option = simple_strtol(ep, NULL, 10);

	ep = env_get("tftpwindowsize");
	if (ep != NULL)
		tftp_window_size_option = simple_strtol(ep, NULL, 10);

	ep = env_get("tftptimeout");
	if (ep != NULL)
		timeout_ms = simple_strtol(ep, NULL, 10);

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

	ep = env_get("tftptimeoutcountmax");
	if (ep != NULL)
		tftp_timeout_count_max = simple_strtol(ep, NULL, 10);

	if (tftp_timeout_count_max < 0) {
		printf("TFTP timeout count max (%d ms) negative, set to 0\n",
		       tftp_timeout_count_max);
		tftp_timeout_count_max = 0;
	}
#endif

	debug("TFTP blocksize = %i, TFTP windowsize = %d timeout = %ld ms\n",
	      tftp_block_size_option, tftp_window_size_option, timeout_ms);

	tftp_remote_ip = net_server_ip;
	if (!net_parse_bootfile(&tftp_remote_ip, tftp_filename, MAX_LEN)) {
		sprintf(default_filename, "%02X%02X%02X%02X.img",
			net_ip.s_addr & 0xFF,
			(net_ip.s_addr >>  8) & 0xFF,
			(net_ip.s_addr >> 16) & 0xFF,
			(net_ip.s_addr >> 24) & 0xFF);

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

		printf("*** Warning: no boot file name; using '%s'\n",
		       tftp_filename);
	}

	printf("Using %s device\n", eth_get_name());
	printf("TFTP %s server %pI4; our IP address is %pI4",
#ifdef CONFIG_CMD_TFTPPUT
	       protocol == TFTPPUT ? "to" : "from",
#else
	       "from",
#endif
	       &tftp_remote_ip, &net_ip);

	/* Check if we need to send across this subnet */
	if (net_gateway.s_addr && net_netmask.s_addr) {
		struct in_addr our_net;
		struct in_addr remote_net;

		our_net.s_addr = net_ip.s_addr & net_netmask.s_addr;
		remote_net.s_addr = tftp_remote_ip.s_addr & net_netmask.s_addr;
		if (our_net.s_addr != remote_net.s_addr)
			printf("; sending through gateway %pI4", &net_gateway);
	}
	putc('\n');

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

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

	putc('\n');
#ifdef CONFIG_CMD_TFTPPUT
	tftp_put_active = (protocol == TFTPPUT);
	if (tftp_put_active) {
		printf("Save address: 0x%lx\n", image_save_addr);
		printf("Save size:    0x%lx\n", image_save_size);
		net_boot_file_size = image_save_size;
		puts("Saving: *\b");
		tftp_state = STATE_SEND_WRQ;
		new_transfer();
	} else
#endif
	{
		if (tftp_init_load_addr()) {
			eth_halt();
			net_set_state(NETLOOP_FAIL);
			puts("\nTFTP error: ");
			puts("trying to overwrite reserved memory...\n");
			return;
		}
		printf("Load address: 0x%lx\n", tftp_load_addr);
		puts("Loading: *\b");
		tftp_state = STATE_SEND_RRQ;
	}

	time_start = get_timer(0);
	timeout_count_max = tftp_timeout_count_max;

	net_set_timeout_handler(timeout_ms, tftp_timeout_handler);
	net_set_udp_handler(tftp_handler);
#ifdef CONFIG_CMD_TFTPPUT
	net_set_icmp_handler(icmp_handler);
#endif
	tftp_remote_port = WELL_KNOWN_PORT;
	timeout_count = 0;
	/* Use a pseudo-random port unless a specific port is set */
	tftp_our_port = 1024 + (get_timer(0) % 3072);

#ifdef CONFIG_TFTP_PORT
	ep = env_get("tftpdstp");
	if (ep != NULL)
		tftp_remote_port = simple_strtol(ep, NULL, 10);
	ep = env_get("tftpsrcp");
	if (ep != NULL)
		tftp_our_port = simple_strtol(ep, NULL, 10);
#endif
	tftp_cur_block = 0;
	tftp_windowsize = 1;
	tftp_last_nack = 0;
	/* zero out server ether in case the server ip has changed */
	memset(net_server_ethaddr, 0, 6);
	/* Revert tftp_block_size to dflt */
	tftp_block_size = TFTP_BLOCK_SIZE;
#ifdef CONFIG_TFTP_TSIZE
	tftp_tsize = 0;
	tftp_tsize_num_hash = 0;
#endif

	tftp_send();
}

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

	if (tftp_init_load_addr()) {
		eth_halt();
		net_set_state(NETLOOP_FAIL);
		puts("\nTFTP error: trying to overwrite reserved memory...\n");
		return;
	}
	printf("Using %s device\n", eth_get_name());
	printf("Listening for TFTP transfer on %pI4\n", &net_ip);
	printf("Load address: 0x%lx\n", tftp_load_addr);

	puts("Loading: *\b");

	timeout_count_max = tftp_timeout_count_max;
	timeout_count = 0;
	timeout_ms = TIMEOUT;
	net_set_timeout_handler(timeout_ms, tftp_timeout_handler);

	/* Revert tftp_block_size to dflt */
	tftp_block_size = TFTP_BLOCK_SIZE;
	tftp_cur_block = 0;
	tftp_our_port = WELL_KNOWN_PORT;

#ifdef CONFIG_TFTP_TSIZE
	tftp_tsize = 0;
	tftp_tsize_num_hash = 0;
#endif

	tftp_state = STATE_RECV_WRQ;
	net_set_udp_handler(tftp_handler);

	/* zero out server ether in case the server ip has changed */
	memset(net_server_ethaddr, 0, 6);
}
#endif /* CONFIG_CMD_TFTPSRV */