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1 /*
2  *      Copyright 1994, 1995, 2000 Neil Russell.
3  *      (See License)
4  *      Copyright 2000, 2001 DENX Software Engineering, Wolfgang Denk, wd@denx.de
5  */
6
7 #include <common.h>
8 #include <command.h>
9 #include <net.h>
10 #include "tftp.h"
11 #include "bootp.h"
12
13 #define WELL_KNOWN_PORT 69              /* Well known TFTP port #               */
14 #define TIMEOUT         5000UL          /* Millisecs to timeout for lost pkt */
15 #ifndef CONFIG_NET_RETRY_COUNT
16 # define TIMEOUT_COUNT  10              /* # of timeouts before giving up  */
17 #else
18 # define TIMEOUT_COUNT  (CONFIG_NET_RETRY_COUNT * 2)
19 #endif
20                                         /* (for checking the image size)        */
21 #define HASHES_PER_LINE 65              /* Number of "loading" hashes per line  */
22
23 /*
24  *      TFTP operations.
25  */
26 #define TFTP_RRQ        1
27 #define TFTP_WRQ        2
28 #define TFTP_DATA       3
29 #define TFTP_ACK        4
30 #define TFTP_ERROR      5
31 #define TFTP_OACK       6
32
33 static ulong TftpTimeoutMSecs = TIMEOUT;
34 static int TftpTimeoutCountMax = TIMEOUT_COUNT;
35
36 /*
37  * These globals govern the timeout behavior when attempting a connection to a
38  * TFTP server. TftpRRQTimeoutMSecs specifies the number of milliseconds to
39  * wait for the server to respond to initial connection. Second global,
40  * TftpRRQTimeoutCountMax, gives the number of such connection retries.
41  * TftpRRQTimeoutCountMax must be non-negative and TftpRRQTimeoutMSecs must be
42  * positive. The globals are meant to be set (and restored) by code needing
43  * non-standard timeout behavior when initiating a TFTP transfer.
44  */
45 ulong TftpRRQTimeoutMSecs = TIMEOUT;
46 int TftpRRQTimeoutCountMax = TIMEOUT_COUNT;
47
48 enum {
49         TFTP_ERR_UNDEFINED           = 0,
50         TFTP_ERR_FILE_NOT_FOUND      = 1,
51         TFTP_ERR_ACCESS_DENIED       = 2,
52         TFTP_ERR_DISK_FULL           = 3,
53         TFTP_ERR_UNEXPECTED_OPCODE   = 4,
54         TFTP_ERR_UNKNOWN_TRANSFER_ID  = 5,
55         TFTP_ERR_FILE_ALREADY_EXISTS = 6,
56 };
57
58 static IPaddr_t TftpServerIP;
59 static int      TftpServerPort;         /* The UDP port at their end            */
60 static int      TftpOurPort;            /* The UDP port at our end              */
61 static int      TftpTimeoutCount;
62 static ulong    TftpBlock;              /* packet sequence number               */
63 static ulong    TftpLastBlock;          /* last packet sequence number received */
64 static ulong    TftpBlockWrap;          /* count of sequence number wraparounds */
65 static ulong    TftpBlockWrapOffset;    /* memory offset due to wrapping        */
66 static int      TftpState;
67 #ifdef CONFIG_TFTP_TSIZE
68 static int      TftpTsize;              /* The file size reported by the server */
69 static short    TftpNumchars;           /* The number of hashes we printed      */
70 #endif
71
72 #define STATE_RRQ       1
73 #define STATE_DATA      2
74 #define STATE_TOO_LARGE 3
75 #define STATE_BAD_MAGIC 4
76 #define STATE_OACK      5
77
78 #define TFTP_BLOCK_SIZE         512                 /* default TFTP block size  */
79 #define TFTP_SEQUENCE_SIZE      ((ulong)(1<<16))    /* sequence number is 16 bit */
80
81 #define DEFAULT_NAME_LEN        (8 + 4 + 1)
82 static char default_filename[DEFAULT_NAME_LEN];
83
84 #ifndef CONFIG_TFTP_FILE_NAME_MAX_LEN
85 #define MAX_LEN 128
86 #else
87 #define MAX_LEN CONFIG_TFTP_FILE_NAME_MAX_LEN
88 #endif
89
90 static char tftp_filename[MAX_LEN];
91
92 #ifdef CONFIG_SYS_DIRECT_FLASH_TFTP
93 extern flash_info_t flash_info[];
94 #endif
95
96 /* 512 is poor choice for ethernet, MTU is typically 1500.
97  * Minus eth.hdrs thats 1468.  Can get 2x better throughput with
98  * almost-MTU block sizes.  At least try... fall back to 512 if need be.
99  * (but those using CONFIG_IP_DEFRAG may want to set a larger block in cfg file)
100  */
101 #ifdef CONFIG_TFTP_BLOCKSIZE
102 #define TFTP_MTU_BLOCKSIZE CONFIG_TFTP_BLOCKSIZE
103 #else
104 #define TFTP_MTU_BLOCKSIZE 1468
105 #endif
106
107 static unsigned short TftpBlkSize=TFTP_BLOCK_SIZE;
108 static unsigned short TftpBlkSizeOption=TFTP_MTU_BLOCKSIZE;
109
110 #ifdef CONFIG_MCAST_TFTP
111 #include <malloc.h>
112 #define MTFTP_BITMAPSIZE        0x1000
113 static unsigned *Bitmap;
114 static int PrevBitmapHole,Mapsize=MTFTP_BITMAPSIZE;
115 static uchar ProhibitMcast=0, MasterClient=0;
116 static uchar Multicast=0;
117 extern IPaddr_t Mcast_addr;
118 static int Mcast_port;
119 static ulong TftpEndingBlock; /* can get 'last' block before done..*/
120
121 static void parse_multicast_oack(char *pkt,int len);
122
123 static void
124 mcast_cleanup(void)
125 {
126         if (Mcast_addr) eth_mcast_join(Mcast_addr, 0);
127         if (Bitmap) free(Bitmap);
128         Bitmap=NULL;
129         Mcast_addr = Multicast = Mcast_port = 0;
130         TftpEndingBlock = -1;
131 }
132
133 #endif  /* CONFIG_MCAST_TFTP */
134
135 static __inline__ void
136 store_block (unsigned block, uchar * src, unsigned len)
137 {
138         ulong offset = block * TftpBlkSize + TftpBlockWrapOffset;
139         ulong newsize = offset + len;
140 #ifdef CONFIG_SYS_DIRECT_FLASH_TFTP
141         int i, rc = 0;
142
143         for (i=0; i<CONFIG_SYS_MAX_FLASH_BANKS; i++) {
144                 /* start address in flash? */
145                 if (flash_info[i].flash_id == FLASH_UNKNOWN)
146                         continue;
147                 if (load_addr + offset >= flash_info[i].start[0]) {
148                         rc = 1;
149                         break;
150                 }
151         }
152
153         if (rc) { /* Flash is destination for this packet */
154                 rc = flash_write ((char *)src, (ulong)(load_addr+offset), len);
155                 if (rc) {
156                         flash_perror (rc);
157                         NetState = NETLOOP_FAIL;
158                         return;
159                 }
160         }
161         else
162 #endif /* CONFIG_SYS_DIRECT_FLASH_TFTP */
163         {
164                 (void)memcpy((void *)(load_addr + offset), src, len);
165         }
166 #ifdef CONFIG_MCAST_TFTP
167         if (Multicast)
168                 ext2_set_bit(block, Bitmap);
169 #endif
170
171         if (NetBootFileXferSize < newsize)
172                 NetBootFileXferSize = newsize;
173 }
174
175 static void TftpSend (void);
176 static void TftpTimeout (void);
177
178 /**********************************************************************/
179
180 static void
181 TftpSend (void)
182 {
183         volatile uchar *        pkt;
184         volatile uchar *        xp;
185         int                     len = 0;
186         volatile ushort *s;
187
188 #ifdef CONFIG_MCAST_TFTP
189         /* Multicast TFTP.. non-MasterClients do not ACK data. */
190         if (Multicast
191          && (TftpState == STATE_DATA)
192          && (MasterClient == 0))
193                 return;
194 #endif
195         /*
196          *      We will always be sending some sort of packet, so
197          *      cobble together the packet headers now.
198          */
199         pkt = NetTxPacket + NetEthHdrSize() + IP_HDR_SIZE;
200
201         switch (TftpState) {
202
203         case STATE_RRQ:
204                 xp = pkt;
205                 s = (ushort *)pkt;
206                 *s++ = htons(TFTP_RRQ);
207                 pkt = (uchar *)s;
208                 strcpy ((char *)pkt, tftp_filename);
209                 pkt += strlen(tftp_filename) + 1;
210                 strcpy ((char *)pkt, "octet");
211                 pkt += 5 /*strlen("octet")*/ + 1;
212                 strcpy ((char *)pkt, "timeout");
213                 pkt += 7 /*strlen("timeout")*/ + 1;
214                 sprintf((char *)pkt, "%lu", TftpTimeoutMSecs / 1000);
215                 debug("send option \"timeout %s\"\n", (char *)pkt);
216                 pkt += strlen((char *)pkt) + 1;
217 #ifdef CONFIG_TFTP_TSIZE
218                 memcpy((char *)pkt, "tsize\0000\0", 8);
219                 pkt += 8;
220 #endif
221                 /* try for more effic. blk size */
222                 pkt += sprintf((char *)pkt,"blksize%c%d%c",
223                                 0,TftpBlkSizeOption,0);
224 #ifdef CONFIG_MCAST_TFTP
225                 /* Check all preconditions before even trying the option */
226                 if (!ProhibitMcast
227                  && (Bitmap=malloc(Mapsize))
228                  && eth_get_dev()->mcast) {
229                         free(Bitmap);
230                         Bitmap=NULL;
231                         pkt += sprintf((char *)pkt,"multicast%c%c",0,0);
232                 }
233 #endif /* CONFIG_MCAST_TFTP */
234                 len = pkt - xp;
235                 break;
236
237         case STATE_OACK:
238 #ifdef CONFIG_MCAST_TFTP
239                 /* My turn!  Start at where I need blocks I missed.*/
240                 if (Multicast)
241                         TftpBlock=ext2_find_next_zero_bit(Bitmap,(Mapsize*8),0);
242                 /*..falling..*/
243 #endif
244         case STATE_DATA:
245                 xp = pkt;
246                 s = (ushort *)pkt;
247                 *s++ = htons(TFTP_ACK);
248                 *s++ = htons(TftpBlock);
249                 pkt = (uchar *)s;
250                 len = pkt - xp;
251                 break;
252
253         case STATE_TOO_LARGE:
254                 xp = pkt;
255                 s = (ushort *)pkt;
256                 *s++ = htons(TFTP_ERROR);
257                 *s++ = htons(3);
258                 pkt = (uchar *)s;
259                 strcpy ((char *)pkt, "File too large");
260                 pkt += 14 /*strlen("File too large")*/ + 1;
261                 len = pkt - xp;
262                 break;
263
264         case STATE_BAD_MAGIC:
265                 xp = pkt;
266                 s = (ushort *)pkt;
267                 *s++ = htons(TFTP_ERROR);
268                 *s++ = htons(2);
269                 pkt = (uchar *)s;
270                 strcpy ((char *)pkt, "File has bad magic");
271                 pkt += 18 /*strlen("File has bad magic")*/ + 1;
272                 len = pkt - xp;
273                 break;
274         }
275
276         NetSendUDPPacket(NetServerEther, TftpServerIP, TftpServerPort, TftpOurPort, len);
277 }
278
279
280 static void
281 TftpHandler (uchar * pkt, unsigned dest, unsigned src, unsigned len)
282 {
283         ushort proto;
284         ushort *s;
285         int i;
286
287         if (dest != TftpOurPort) {
288 #ifdef CONFIG_MCAST_TFTP
289                 if (Multicast
290                  && (!Mcast_port || (dest != Mcast_port)))
291 #endif
292                 return;
293         }
294         if (TftpState != STATE_RRQ && src != TftpServerPort) {
295                 return;
296         }
297
298         if (len < 2) {
299                 return;
300         }
301         len -= 2;
302         /* warning: don't use increment (++) in ntohs() macros!! */
303         s = (ushort *)pkt;
304         proto = *s++;
305         pkt = (uchar *)s;
306         switch (ntohs(proto)) {
307
308         case TFTP_RRQ:
309         case TFTP_WRQ:
310         case TFTP_ACK:
311                 break;
312         default:
313                 break;
314
315         case TFTP_OACK:
316                 debug("Got OACK: %s %s\n",
317                         pkt,
318                         pkt + strlen((char *)pkt) + 1);
319                 TftpState = STATE_OACK;
320                 TftpServerPort = src;
321                 /*
322                  * Check for 'blksize' option.
323                  * Careful: "i" is signed, "len" is unsigned, thus
324                  * something like "len-8" may give a *huge* number
325                  */
326                 for (i=0; i+8<len; i++) {
327                         if (strcmp ((char*)pkt+i,"blksize") == 0) {
328                                 TftpBlkSize = (unsigned short)
329                                         simple_strtoul((char*)pkt+i+8,NULL,10);
330                                 debug("Blocksize ack: %s, %d\n",
331                                         (char*)pkt+i+8,TftpBlkSize);
332                         }
333 #ifdef CONFIG_TFTP_TSIZE
334                         if (strcmp ((char*)pkt+i,"tsize") == 0) {
335                                 TftpTsize = simple_strtoul((char*)pkt+i+6,NULL,10);
336                                 debug("size = %s, %d\n",
337                                          (char*)pkt+i+6, TftpTsize);
338                         }
339 #endif
340                 }
341 #ifdef CONFIG_MCAST_TFTP
342                 parse_multicast_oack((char *)pkt,len-1);
343                 if ((Multicast) && (!MasterClient))
344                         TftpState = STATE_DATA; /* passive.. */
345                 else
346 #endif
347                 TftpSend (); /* Send ACK */
348                 break;
349         case TFTP_DATA:
350                 if (len < 2)
351                         return;
352                 len -= 2;
353                 TftpBlock = ntohs(*(ushort *)pkt);
354
355                 /*
356                  * RFC1350 specifies that the first data packet will
357                  * have sequence number 1. If we receive a sequence
358                  * number of 0 this means that there was a wrap
359                  * around of the (16 bit) counter.
360                  */
361                 if (TftpBlock == 0) {
362                         TftpBlockWrap++;
363                         TftpBlockWrapOffset += TftpBlkSize * TFTP_SEQUENCE_SIZE;
364                         printf ("\n\t %lu MB received\n\t ", TftpBlockWrapOffset>>20);
365                 }
366 #ifdef CONFIG_TFTP_TSIZE
367                 else if (TftpTsize) {
368                         while (TftpNumchars < NetBootFileXferSize * 50 / TftpTsize) {
369                                 putc('#');
370                                 TftpNumchars++;
371                         }
372                 }
373 #endif
374                 else {
375                         if (((TftpBlock - 1) % 10) == 0) {
376                                 putc ('#');
377                         } else if ((TftpBlock % (10 * HASHES_PER_LINE)) == 0) {
378                                 puts ("\n\t ");
379                         }
380                 }
381
382                 if (TftpState == STATE_RRQ)
383                         debug("Server did not acknowledge timeout option!\n");
384
385                 if (TftpState == STATE_RRQ || TftpState == STATE_OACK) {
386                         /* first block received */
387                         TftpState = STATE_DATA;
388                         TftpServerPort = src;
389                         TftpLastBlock = 0;
390                         TftpBlockWrap = 0;
391                         TftpBlockWrapOffset = 0;
392
393 #ifdef CONFIG_MCAST_TFTP
394                         if (Multicast) { /* start!=1 common if mcast */
395                                 TftpLastBlock = TftpBlock - 1;
396                         } else
397 #endif
398                         if (TftpBlock != 1) {   /* Assertion */
399                                 printf ("\nTFTP error: "
400                                         "First block is not block 1 (%ld)\n"
401                                         "Starting again\n\n",
402                                         TftpBlock);
403                                 NetStartAgain ();
404                                 break;
405                         }
406                 }
407
408                 if (TftpBlock == TftpLastBlock) {
409                         /*
410                          *      Same block again; ignore it.
411                          */
412                         break;
413                 }
414
415                 TftpLastBlock = TftpBlock;
416                 TftpTimeoutCountMax = TIMEOUT_COUNT;
417                 NetSetTimeout (TftpTimeoutMSecs, TftpTimeout);
418
419                 store_block (TftpBlock - 1, pkt + 2, len);
420
421                 /*
422                  *      Acknoledge the block just received, which will prompt
423                  *      the server for the next one.
424                  */
425 #ifdef CONFIG_MCAST_TFTP
426                 /* if I am the MasterClient, actively calculate what my next
427                  * needed block is; else I'm passive; not ACKING
428                  */
429                 if (Multicast) {
430                         if (len < TftpBlkSize)  {
431                                 TftpEndingBlock = TftpBlock;
432                         } else if (MasterClient) {
433                                 TftpBlock = PrevBitmapHole =
434                                         ext2_find_next_zero_bit(
435                                                 Bitmap,
436                                                 (Mapsize*8),
437                                                 PrevBitmapHole);
438                                 if (TftpBlock > ((Mapsize*8) - 1)) {
439                                         printf ("tftpfile too big\n");
440                                         /* try to double it and retry */
441                                         Mapsize<<=1;
442                                         mcast_cleanup();
443                                         NetStartAgain ();
444                                         return;
445                                 }
446                                 TftpLastBlock = TftpBlock;
447                         }
448                 }
449 #endif
450                 TftpSend ();
451
452 #ifdef CONFIG_MCAST_TFTP
453                 if (Multicast) {
454                         if (MasterClient && (TftpBlock >= TftpEndingBlock)) {
455                                 puts ("\nMulticast tftp done\n");
456                                 mcast_cleanup();
457                                 NetState = NETLOOP_SUCCESS;
458                         }
459                 }
460                 else
461 #endif
462                 if (len < TftpBlkSize) {
463                         /*
464                          *      We received the whole thing.  Try to
465                          *      run it.
466                          */
467 #ifdef CONFIG_TFTP_TSIZE
468                         /* Print out the hash marks for the last packet received */
469                         while (TftpTsize && TftpNumchars < 49) {
470                                 putc('#');
471                                 TftpNumchars++;
472                         }
473 #endif
474                         puts ("\ndone\n");
475                         NetState = NETLOOP_SUCCESS;
476                 }
477                 break;
478
479         case TFTP_ERROR:
480                 printf ("\nTFTP error: '%s' (%d)\n",
481                                         pkt + 2, ntohs(*(ushort *)pkt));
482
483                 switch (ntohs(*(ushort *)pkt)) {
484                 case TFTP_ERR_FILE_NOT_FOUND:
485                 case TFTP_ERR_ACCESS_DENIED:
486                         puts("Not retrying...\n");
487                         eth_halt();
488                         NetState = NETLOOP_FAIL;
489                         break;
490                 case TFTP_ERR_UNDEFINED:
491                 case TFTP_ERR_DISK_FULL:
492                 case TFTP_ERR_UNEXPECTED_OPCODE:
493                 case TFTP_ERR_UNKNOWN_TRANSFER_ID:
494                 case TFTP_ERR_FILE_ALREADY_EXISTS:
495                 default:
496                         puts("Starting again\n\n");
497 #ifdef CONFIG_MCAST_TFTP
498                         mcast_cleanup();
499 #endif
500                         NetStartAgain();
501                         break;
502                 }
503                 break;
504         }
505 }
506
507
508 static void
509 TftpTimeout (void)
510 {
511         if (++TftpTimeoutCount > TftpTimeoutCountMax) {
512                 puts ("\nRetry count exceeded; starting again\n");
513 #ifdef CONFIG_MCAST_TFTP
514                 mcast_cleanup();
515 #endif
516                 NetStartAgain ();
517         } else {
518                 puts ("T ");
519                 NetSetTimeout (TftpTimeoutMSecs, TftpTimeout);
520                 TftpSend ();
521         }
522 }
523
524
525 void
526 TftpStart (void)
527 {
528         char *ep;             /* Environment pointer */
529
530         /*
531          * Allow the user to choose TFTP blocksize and timeout.
532          * TFTP protocol has a minimal timeout of 1 second.
533          */
534         if ((ep = getenv("tftpblocksize")) != NULL)
535                 TftpBlkSizeOption = simple_strtol(ep, NULL, 10);
536
537         if ((ep = getenv("tftptimeout")) != NULL)
538                 TftpTimeoutMSecs = simple_strtol(ep, NULL, 10);
539
540         if (TftpTimeoutMSecs < 1000) {
541                 printf("TFTP timeout (%ld ms) too low, "
542                         "set minimum = 1000 ms\n",
543                         TftpTimeoutMSecs);
544                 TftpTimeoutMSecs = 1000;
545         }
546
547         debug("TFTP blocksize = %i, timeout = %ld ms\n",
548                 TftpBlkSizeOption, TftpTimeoutMSecs);
549
550         TftpServerIP = NetServerIP;
551         if (BootFile[0] == '\0') {
552                 sprintf(default_filename, "%02lX%02lX%02lX%02lX.img",
553                         NetOurIP & 0xFF,
554                         (NetOurIP >>  8) & 0xFF,
555                         (NetOurIP >> 16) & 0xFF,
556                         (NetOurIP >> 24) & 0xFF );
557
558                 strncpy(tftp_filename, default_filename, MAX_LEN);
559                 tftp_filename[MAX_LEN-1] = 0;
560
561                 printf ("*** Warning: no boot file name; using '%s'\n",
562                         tftp_filename);
563         } else {
564                 char *p = strchr (BootFile, ':');
565
566                 if (p == NULL) {
567                         strncpy(tftp_filename, BootFile, MAX_LEN);
568                         tftp_filename[MAX_LEN-1] = 0;
569                 } else {
570                         TftpServerIP = string_to_ip (BootFile);
571                         strncpy(tftp_filename, p + 1, MAX_LEN);
572                         tftp_filename[MAX_LEN-1] = 0;
573                 }
574         }
575
576 #if defined(CONFIG_NET_MULTI)
577         printf ("Using %s device\n", eth_get_name());
578 #endif
579         printf("TFTP from server %pI4"
580                 "; our IP address is %pI4", &TftpServerIP, &NetOurIP);
581
582         /* Check if we need to send across this subnet */
583         if (NetOurGatewayIP && NetOurSubnetMask) {
584             IPaddr_t OurNet     = NetOurIP    & NetOurSubnetMask;
585             IPaddr_t ServerNet  = TftpServerIP & NetOurSubnetMask;
586
587             if (OurNet != ServerNet)
588                 printf("; sending through gateway %pI4", &NetOurGatewayIP);
589         }
590         putc ('\n');
591
592         printf ("Filename '%s'.", tftp_filename);
593
594         if (NetBootFileSize) {
595                 printf (" Size is 0x%x Bytes = ", NetBootFileSize<<9);
596                 print_size (NetBootFileSize<<9, "");
597         }
598
599         putc ('\n');
600
601         printf ("Load address: 0x%lx\n", load_addr);
602
603         puts ("Loading: *\b");
604
605         TftpTimeoutCountMax = TftpRRQTimeoutCountMax;
606
607         NetSetTimeout (TftpTimeoutMSecs, TftpTimeout);
608         NetSetHandler (TftpHandler);
609
610         TftpServerPort = WELL_KNOWN_PORT;
611         TftpTimeoutCount = 0;
612         TftpState = STATE_RRQ;
613         /* Use a pseudo-random port unless a specific port is set */
614         TftpOurPort = 1024 + (get_timer(0) % 3072);
615
616 #ifdef CONFIG_TFTP_PORT
617         if ((ep = getenv("tftpdstp")) != NULL) {
618                 TftpServerPort = simple_strtol(ep, NULL, 10);
619         }
620         if ((ep = getenv("tftpsrcp")) != NULL) {
621                 TftpOurPort= simple_strtol(ep, NULL, 10);
622         }
623 #endif
624         TftpBlock = 0;
625
626         /* zero out server ether in case the server ip has changed */
627         memset(NetServerEther, 0, 6);
628         /* Revert TftpBlkSize to dflt */
629         TftpBlkSize = TFTP_BLOCK_SIZE;
630 #ifdef CONFIG_MCAST_TFTP
631         mcast_cleanup();
632 #endif
633 #ifdef CONFIG_TFTP_TSIZE
634         TftpTsize = 0;
635         TftpNumchars = 0;
636 #endif
637
638         TftpSend ();
639 }
640
641 #ifdef CONFIG_MCAST_TFTP
642 /* Credits: atftp project.
643  */
644
645 /* pick up BcastAddr, Port, and whether I am [now] the master-client. *
646  * Frame:
647  *    +-------+-----------+---+-------~~-------+---+
648  *    |  opc  | multicast | 0 | addr, port, mc | 0 |
649  *    +-------+-----------+---+-------~~-------+---+
650  * The multicast addr/port becomes what I listen to, and if 'mc' is '1' then
651  * I am the new master-client so must send ACKs to DataBlocks.  If I am not
652  * master-client, I'm a passive client, gathering what DataBlocks I may and
653  * making note of which ones I got in my bitmask.
654  * In theory, I never go from master->passive..
655  * .. this comes in with pkt already pointing just past opc
656  */
657 static void parse_multicast_oack(char *pkt, int len)
658 {
659  int i;
660  IPaddr_t addr;
661  char *mc_adr, *port,  *mc;
662
663         mc_adr=port=mc=NULL;
664         /* march along looking for 'multicast\0', which has to start at least
665          * 14 bytes back from the end.
666          */
667         for (i=0;i<len-14;i++)
668                 if (strcmp (pkt+i,"multicast") == 0)
669                         break;
670         if (i >= (len-14)) /* non-Multicast OACK, ign. */
671                 return;
672
673         i+=10; /* strlen multicast */
674         mc_adr = pkt+i;
675         for (;i<len;i++) {
676                 if (*(pkt+i) == ',') {
677                         *(pkt+i) = '\0';
678                         if (port) {
679                                 mc = pkt+i+1;
680                                 break;
681                         } else {
682                                 port = pkt+i+1;
683                         }
684                 }
685         }
686         if (!port || !mc_adr || !mc ) return;
687         if (Multicast && MasterClient) {
688                 printf ("I got a OACK as master Client, WRONG!\n");
689                 return;
690         }
691         /* ..I now accept packets destined for this MCAST addr, port */
692         if (!Multicast) {
693                 if (Bitmap) {
694                         printf ("Internal failure! no mcast.\n");
695                         free(Bitmap);
696                         Bitmap=NULL;
697                         ProhibitMcast=1;
698                         return ;
699                 }
700                 /* I malloc instead of pre-declare; so that if the file ends
701                  * up being too big for this bitmap I can retry
702                  */
703                 if (!(Bitmap = malloc (Mapsize))) {
704                         printf ("No Bitmap, no multicast. Sorry.\n");
705                         ProhibitMcast=1;
706                         return;
707                 }
708                 memset (Bitmap,0,Mapsize);
709                 PrevBitmapHole = 0;
710                 Multicast = 1;
711         }
712         addr = string_to_ip(mc_adr);
713         if (Mcast_addr != addr) {
714                 if (Mcast_addr)
715                         eth_mcast_join(Mcast_addr, 0);
716                 if (eth_mcast_join(Mcast_addr=addr, 1)) {
717                         printf ("Fail to set mcast, revert to TFTP\n");
718                         ProhibitMcast=1;
719                         mcast_cleanup();
720                         NetStartAgain();
721                 }
722         }
723         MasterClient = (unsigned char)simple_strtoul((char *)mc,NULL,10);
724         Mcast_port = (unsigned short)simple_strtoul(port,NULL,10);
725         printf ("Multicast: %s:%d [%d]\n", mc_adr, Mcast_port, MasterClient);
726         return;
727 }
728
729 #endif /* Multicast TFTP */