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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [CORTEX_LPC1768_GCC_RedSuite/] [src/] [webserver/] [uip.c] - Blame information for rev 581

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1 581 jeremybenn
#define DEBUG_PRINTF(...) /*printf(__VA_ARGS__)*/
2
 
3
/**
4
 * \defgroup uip The uIP TCP/IP stack
5
 * @{
6
 *
7
 * uIP is an implementation of the TCP/IP protocol stack intended for
8
 * small 8-bit and 16-bit microcontrollers.
9
 *
10
 * uIP provides the necessary protocols for Internet communication,
11
 * with a very small code footprint and RAM requirements - the uIP
12
 * code size is on the order of a few kilobytes and RAM usage is on
13
 * the order of a few hundred bytes.
14
 */
15
 
16
/**
17
 * \file
18
 * The uIP TCP/IP stack code.
19
 * \author Adam Dunkels <adam@dunkels.com>
20
 */
21
 
22
/*
23
 * Copyright (c) 2001-2003, Adam Dunkels.
24
 * All rights reserved.
25
 *
26
 * Redistribution and use in source and binary forms, with or without
27
 * modification, are permitted provided that the following conditions
28
 * are met:
29
 * 1. Redistributions of source code must retain the above copyright
30
 *    notice, this list of conditions and the following disclaimer.
31
 * 2. Redistributions in binary form must reproduce the above copyright
32
 *    notice, this list of conditions and the following disclaimer in the
33
 *    documentation and/or other materials provided with the distribution.
34
 * 3. The name of the author may not be used to endorse or promote
35
 *    products derived from this software without specific prior
36
 *    written permission.
37
 *
38
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
39
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
40
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
41
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
42
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
43
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
44
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
45
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
46
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
47
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
48
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
49
 *
50
 * This file is part of the uIP TCP/IP stack.
51
 *
52
 * $Id: uip.c 2 2011-07-17 20:13:17Z filepang@gmail.com $
53
 *
54
 */
55
 
56
/*
57
 * uIP is a small implementation of the IP, UDP and TCP protocols (as
58
 * well as some basic ICMP stuff). The implementation couples the IP,
59
 * UDP, TCP and the application layers very tightly. To keep the size
60
 * of the compiled code down, this code frequently uses the goto
61
 * statement. While it would be possible to break the uip_process()
62
 * function into many smaller functions, this would increase the code
63
 * size because of the overhead of parameter passing and the fact that
64
 * the optimier would not be as efficient.
65
 *
66
 * The principle is that we have a small buffer, called the uip_buf,
67
 * in which the device driver puts an incoming packet. The TCP/IP
68
 * stack parses the headers in the packet, and calls the
69
 * application. If the remote host has sent data to the application,
70
 * this data is present in the uip_buf and the application read the
71
 * data from there. It is up to the application to put this data into
72
 * a byte stream if needed. The application will not be fed with data
73
 * that is out of sequence.
74
 *
75
 * If the application whishes to send data to the peer, it should put
76
 * its data into the uip_buf. The uip_appdata pointer points to the
77
 * first available byte. The TCP/IP stack will calculate the
78
 * checksums, and fill in the necessary header fields and finally send
79
 * the packet back to the peer.
80
*/
81
 
82
#include "uip.h"
83
#include "uipopt.h"
84
#include "uip_arch.h"
85
 
86
#if UIP_CONF_IPV6
87
#include "uip-neighbor.h"
88
#endif /* UIP_CONF_IPV6 */
89
 
90
#include <string.h>
91
 
92
/*---------------------------------------------------------------------------*/
93
/* Variable definitions. */
94
 
95
 
96
/* The IP address of this host. If it is defined to be fixed (by
97
   setting UIP_FIXEDADDR to 1 in uipopt.h), the address is set
98
   here. Otherwise, the address */
99
#if UIP_FIXEDADDR > 0
100
const uip_ipaddr_t uip_hostaddr =
101
  {HTONS((UIP_IPADDR0 << 8) | UIP_IPADDR1),
102
   HTONS((UIP_IPADDR2 << 8) | UIP_IPADDR3)};
103
const uip_ipaddr_t uip_draddr =
104
  {HTONS((UIP_DRIPADDR0 << 8) | UIP_DRIPADDR1),
105
   HTONS((UIP_DRIPADDR2 << 8) | UIP_DRIPADDR3)};
106
const uip_ipaddr_t uip_netmask =
107
  {HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1),
108
   HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3)};
109
#else
110
uip_ipaddr_t uip_hostaddr, uip_draddr, uip_netmask;
111
#endif /* UIP_FIXEDADDR */
112
 
113
static const uip_ipaddr_t all_ones_addr =
114
#if UIP_CONF_IPV6
115
  {0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff};
116
#else /* UIP_CONF_IPV6 */
117
  {0xffff,0xffff};
118
#endif /* UIP_CONF_IPV6 */
119
static const uip_ipaddr_t all_zeroes_addr =
120
#if UIP_CONF_IPV6
121
  {0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000};
122
#else /* UIP_CONF_IPV6 */
123
  {0x0000,0x0000};
124
#endif /* UIP_CONF_IPV6 */
125
 
126
#if UIP_FIXEDETHADDR
127
const struct uip_eth_addr uip_ethaddr = {{UIP_ETHADDR0,
128
                                          UIP_ETHADDR1,
129
                                          UIP_ETHADDR2,
130
                                          UIP_ETHADDR3,
131
                                          UIP_ETHADDR4,
132
                                          UIP_ETHADDR5}};
133
#else
134
struct uip_eth_addr uip_ethaddr = {{0,0,0,0,0,0}};
135
#endif
136
 
137
#ifndef UIP_CONF_EXTERNAL_BUFFER
138
 
139
#ifdef __ICCARM__
140
        #pragma data_alignment=4
141
                u8_t uip_buf[UIP_BUFSIZE + 2]; /* The packet buffer that contains incoming packets. */
142
#else
143
        u8_t uip_buf[UIP_BUFSIZE + 2] ALIGN_STRUCT_END; /* The packet buffer that contains incoming packets. */
144
#endif
145
 
146
#endif /* UIP_CONF_EXTERNAL_BUFFER */
147
 
148
void *uip_appdata;               /* The uip_appdata pointer points to
149
                                    application data. */
150
void *uip_sappdata;              /* The uip_appdata pointer points to
151
                                    the application data which is to
152
                                    be sent. */
153
#if UIP_URGDATA > 0
154
void *uip_urgdata;               /* The uip_urgdata pointer points to
155
                                    urgent data (out-of-band data), if
156
                                    present. */
157
u16_t uip_urglen, uip_surglen;
158
#endif /* UIP_URGDATA > 0 */
159
 
160
u16_t uip_len, uip_slen;
161
                             /* The uip_len is either 8 or 16 bits,
162
                                depending on the maximum packet
163
                                size. */
164
 
165
u8_t uip_flags;     /* The uip_flags variable is used for
166
                                communication between the TCP/IP stack
167
                                and the application program. */
168
struct uip_conn *uip_conn;   /* uip_conn always points to the current
169
                                connection. */
170
 
171
struct uip_conn uip_conns[UIP_CONNS];
172
                             /* The uip_conns array holds all TCP
173
                                connections. */
174
u16_t uip_listenports[UIP_LISTENPORTS];
175
                             /* The uip_listenports list all currently
176
                                listning ports. */
177
#if UIP_UDP
178
struct uip_udp_conn *uip_udp_conn;
179
struct uip_udp_conn uip_udp_conns[UIP_UDP_CONNS];
180
#endif /* UIP_UDP */
181
 
182
static u16_t ipid;           /* Ths ipid variable is an increasing
183
                                number that is used for the IP ID
184
                                field. */
185
 
186
void uip_setipid(u16_t id) { ipid = id; }
187
 
188
static u8_t iss[4];          /* The iss variable is used for the TCP
189
                                initial sequence number. */
190
 
191
#if UIP_ACTIVE_OPEN
192
static u16_t lastport;       /* Keeps track of the last port used for
193
                                a new connection. */
194
#endif /* UIP_ACTIVE_OPEN */
195
 
196
/* Temporary variables. */
197
u8_t uip_acc32[4];
198
static u8_t c, opt;
199
static u16_t tmp16;
200
 
201
/* Structures and definitions. */
202
#define TCP_FIN 0x01
203
#define TCP_SYN 0x02
204
#define TCP_RST 0x04
205
#define TCP_PSH 0x08
206
#define TCP_ACK 0x10
207
#define TCP_URG 0x20
208
#define TCP_CTL 0x3f
209
 
210
#define TCP_OPT_END     0   /* End of TCP options list */
211
#define TCP_OPT_NOOP    1   /* "No-operation" TCP option */
212
#define TCP_OPT_MSS     2   /* Maximum segment size TCP option */
213
 
214
#define TCP_OPT_MSS_LEN 4   /* Length of TCP MSS option. */
215
 
216
#define ICMP_ECHO_REPLY 0
217
#define ICMP_ECHO       8
218
 
219
#define ICMP6_ECHO_REPLY             129
220
#define ICMP6_ECHO                   128
221
#define ICMP6_NEIGHBOR_SOLICITATION  135
222
#define ICMP6_NEIGHBOR_ADVERTISEMENT 136
223
 
224
#define ICMP6_FLAG_S (1 << 6)
225
 
226
#define ICMP6_OPTION_SOURCE_LINK_ADDRESS 1
227
#define ICMP6_OPTION_TARGET_LINK_ADDRESS 2
228
 
229
 
230
/* Macros. */
231
#define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
232
#define FBUF ((struct uip_tcpip_hdr *)&uip_reassbuf[0])
233
#define ICMPBUF ((struct uip_icmpip_hdr *)&uip_buf[UIP_LLH_LEN])
234
#define UDPBUF ((struct uip_udpip_hdr *)&uip_buf[UIP_LLH_LEN])
235
 
236
 
237
#if UIP_STATISTICS == 1
238
struct uip_stats uip_stat;
239
#define UIP_STAT(s) s
240
#else
241
#define UIP_STAT(s)
242
#endif /* UIP_STATISTICS == 1 */
243
 
244
#if UIP_LOGGING == 1
245
#include <stdio.h>
246
void uip_log(char *msg);
247
#define UIP_LOG(m) uip_log(m)
248
#else
249
#define UIP_LOG(m)
250
#endif /* UIP_LOGGING == 1 */
251
 
252
#if ! UIP_ARCH_ADD32
253
void
254
uip_add32(u8_t *op32, u16_t op16)
255
{
256
  uip_acc32[3] = op32[3] + (op16 & 0xff);
257
  uip_acc32[2] = op32[2] + (op16 >> 8);
258
  uip_acc32[1] = op32[1];
259
  uip_acc32[0] = op32[0];
260
 
261
  if(uip_acc32[2] < (op16 >> 8)) {
262
    ++uip_acc32[1];
263
    if(uip_acc32[1] == 0) {
264
      ++uip_acc32[0];
265
    }
266
  }
267
 
268
 
269
  if(uip_acc32[3] < (op16 & 0xff)) {
270
    ++uip_acc32[2];
271
    if(uip_acc32[2] == 0) {
272
      ++uip_acc32[1];
273
      if(uip_acc32[1] == 0) {
274
        ++uip_acc32[0];
275
      }
276
    }
277
  }
278
}
279
 
280
#endif /* UIP_ARCH_ADD32 */
281
 
282
#if ! UIP_ARCH_CHKSUM
283
/*---------------------------------------------------------------------------*/
284
static u16_t
285
chksum(u16_t sum, const u8_t *data, u16_t len)
286
{
287
  u16_t t;
288
  const u8_t *dataptr;
289
  const u8_t *last_byte;
290
 
291
  dataptr = data;
292
  last_byte = data + len - 1;
293
 
294
  while(dataptr < last_byte) {  /* At least two more bytes */
295
    t = (dataptr[0] << 8) + dataptr[1];
296
    sum += t;
297
    if(sum < t) {
298
      sum++;            /* carry */
299
    }
300
    dataptr += 2;
301
  }
302
 
303
  if(dataptr == last_byte) {
304
    t = (dataptr[0] << 8) + 0;
305
    sum += t;
306
    if(sum < t) {
307
      sum++;            /* carry */
308
    }
309
  }
310
 
311
  /* Return sum in host byte order. */
312
  return sum;
313
}
314
/*---------------------------------------------------------------------------*/
315
u16_t
316
uip_chksum(u16_t *data, u16_t len)
317
{
318
  return htons(chksum(0, (u8_t *)data, len));
319
}
320
/*---------------------------------------------------------------------------*/
321
#ifndef UIP_ARCH_IPCHKSUM
322
u16_t
323
uip_ipchksum(void)
324
{
325
  u16_t sum;
326
 
327
  sum = chksum(0, &uip_buf[UIP_LLH_LEN], UIP_IPH_LEN);
328
  DEBUG_PRINTF("uip_ipchksum: sum 0x%04x\n", sum);
329
  return (sum == 0) ? 0xffff : htons(sum);
330
}
331
#endif
332
/*---------------------------------------------------------------------------*/
333
static u16_t
334
upper_layer_chksum(u8_t proto)
335
{
336
  u16_t upper_layer_len;
337
  u16_t sum;
338
 
339
#if UIP_CONF_IPV6
340
  upper_layer_len = (((u16_t)(BUF->len[0]) << 8) + BUF->len[1]);
341
#else /* UIP_CONF_IPV6 */
342
  upper_layer_len = (((u16_t)(BUF->len[0]) << 8) + BUF->len[1]) - UIP_IPH_LEN;
343
#endif /* UIP_CONF_IPV6 */
344
 
345
  /* First sum pseudoheader. */
346
 
347
  /* IP protocol and length fields. This addition cannot carry. */
348
  sum = upper_layer_len + proto;
349
  /* Sum IP source and destination addresses. */
350
  sum = chksum(sum, (u8_t *)&BUF->srcipaddr[0], 2 * sizeof(uip_ipaddr_t));
351
 
352
  /* Sum TCP header and data. */
353
  sum = chksum(sum, &uip_buf[UIP_IPH_LEN + UIP_LLH_LEN],
354
               upper_layer_len);
355
 
356
  return (sum == 0) ? 0xffff : htons(sum);
357
}
358
/*---------------------------------------------------------------------------*/
359
#if UIP_CONF_IPV6
360
u16_t
361
uip_icmp6chksum(void)
362
{
363
  return upper_layer_chksum(UIP_PROTO_ICMP6);
364
 
365
}
366
#endif /* UIP_CONF_IPV6 */
367
/*---------------------------------------------------------------------------*/
368
u16_t
369
uip_tcpchksum(void)
370
{
371
  return upper_layer_chksum(UIP_PROTO_TCP);
372
}
373
/*---------------------------------------------------------------------------*/
374
#if UIP_UDP_CHECKSUMS
375
u16_t
376
uip_udpchksum(void)
377
{
378
  return upper_layer_chksum(UIP_PROTO_UDP);
379
}
380
#endif /* UIP_UDP_CHECKSUMS */
381
#endif /* UIP_ARCH_CHKSUM */
382
/*---------------------------------------------------------------------------*/
383
void
384
uip_init(void)
385
{
386
  for(c = 0; c < UIP_LISTENPORTS; ++c) {
387
    uip_listenports[c] = 0;
388
  }
389
  for(c = 0; c < UIP_CONNS; ++c) {
390
    uip_conns[c].tcpstateflags = UIP_CLOSED;
391
  }
392
#if UIP_ACTIVE_OPEN
393
  lastport = 1024;
394
#endif /* UIP_ACTIVE_OPEN */
395
 
396
#if UIP_UDP
397
  for(c = 0; c < UIP_UDP_CONNS; ++c) {
398
    uip_udp_conns[c].lport = 0;
399
  }
400
#endif /* UIP_UDP */
401
 
402
 
403
  /* IPv4 initialization. */
404
#if UIP_FIXEDADDR == 0
405
  /*  uip_hostaddr[0] = uip_hostaddr[1] = 0;*/
406
#endif /* UIP_FIXEDADDR */
407
 
408
}
409
/*---------------------------------------------------------------------------*/
410
#if UIP_ACTIVE_OPEN
411
struct uip_conn *
412
uip_connect(uip_ipaddr_t *ripaddr, u16_t rport)
413
{
414
  register struct uip_conn *conn, *cconn;
415
 
416
  /* Find an unused local port. */
417
 again:
418
  ++lastport;
419
 
420
  if(lastport >= 32000) {
421
    lastport = 4096;
422
  }
423
 
424
  /* Check if this port is already in use, and if so try to find
425
     another one. */
426
  for(c = 0; c < UIP_CONNS; ++c) {
427
    conn = &uip_conns[c];
428
    if(conn->tcpstateflags != UIP_CLOSED &&
429
       conn->lport == htons(lastport)) {
430
      goto again;
431
    }
432
  }
433
 
434
  conn = 0;
435
  for(c = 0; c < UIP_CONNS; ++c) {
436
    cconn = &uip_conns[c];
437
    if(cconn->tcpstateflags == UIP_CLOSED) {
438
      conn = cconn;
439
      break;
440
    }
441
    if(cconn->tcpstateflags == UIP_TIME_WAIT) {
442
      if(conn == 0 ||
443
         cconn->timer > conn->timer) {
444
        conn = cconn;
445
      }
446
    }
447
  }
448
 
449
  if(conn == 0) {
450
    return 0;
451
  }
452
 
453
  conn->tcpstateflags = UIP_SYN_SENT;
454
 
455
  conn->snd_nxt[0] = iss[0];
456
  conn->snd_nxt[1] = iss[1];
457
  conn->snd_nxt[2] = iss[2];
458
  conn->snd_nxt[3] = iss[3];
459
 
460
  conn->initialmss = conn->mss = UIP_TCP_MSS;
461
 
462
  conn->len = 1;   /* TCP length of the SYN is one. */
463
  conn->nrtx = 0;
464
  conn->timer = 1; /* Send the SYN next time around. */
465
  conn->rto = UIP_RTO;
466
  conn->sa = 0;
467
  conn->sv = 16;   /* Initial value of the RTT variance. */
468
  conn->lport = htons(lastport);
469
  conn->rport = rport;
470
  uip_ipaddr_copy(&conn->ripaddr, ripaddr);
471
 
472
  return conn;
473
}
474
#endif /* UIP_ACTIVE_OPEN */
475
/*---------------------------------------------------------------------------*/
476
#if UIP_UDP
477
struct uip_udp_conn *
478
uip_udp_new(uip_ipaddr_t *ripaddr, u16_t rport)
479
{
480
  register struct uip_udp_conn *conn;
481
 
482
  /* Find an unused local port. */
483
 again:
484
  ++lastport;
485
 
486
  if(lastport >= 32000) {
487
    lastport = 4096;
488
  }
489
 
490
  for(c = 0; c < UIP_UDP_CONNS; ++c) {
491
    if(uip_udp_conns[c].lport == htons(lastport)) {
492
      goto again;
493
    }
494
  }
495
 
496
 
497
  conn = 0;
498
  for(c = 0; c < UIP_UDP_CONNS; ++c) {
499
    if(uip_udp_conns[c].lport == 0) {
500
      conn = &uip_udp_conns[c];
501
      break;
502
    }
503
  }
504
 
505
  if(conn == 0) {
506
    return 0;
507
  }
508
 
509
  conn->lport = HTONS(lastport);
510
  conn->rport = rport;
511
  if(ripaddr == NULL) {
512
    memset(conn->ripaddr, 0, sizeof(uip_ipaddr_t));
513
  } else {
514
    uip_ipaddr_copy(&conn->ripaddr, ripaddr);
515
  }
516
  conn->ttl = UIP_TTL;
517
 
518
  return conn;
519
}
520
#endif /* UIP_UDP */
521
/*---------------------------------------------------------------------------*/
522
void
523
uip_unlisten(u16_t port)
524
{
525
  for(c = 0; c < UIP_LISTENPORTS; ++c) {
526
    if(uip_listenports[c] == port) {
527
      uip_listenports[c] = 0;
528
      return;
529
    }
530
  }
531
}
532
/*---------------------------------------------------------------------------*/
533
void
534
uip_listen(u16_t port)
535
{
536
  for(c = 0; c < UIP_LISTENPORTS; ++c) {
537
    if(uip_listenports[c] == 0) {
538
      uip_listenports[c] = port;
539
      return;
540
    }
541
  }
542
}
543
/*---------------------------------------------------------------------------*/
544
/* XXX: IP fragment reassembly: not well-tested. */
545
 
546
#if UIP_REASSEMBLY && !UIP_CONF_IPV6
547
#define UIP_REASS_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN)
548
static u8_t uip_reassbuf[UIP_REASS_BUFSIZE];
549
static u8_t uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)];
550
static const u8_t bitmap_bits[8] = {0xff, 0x7f, 0x3f, 0x1f,
551
                                    0x0f, 0x07, 0x03, 0x01};
552
static u16_t uip_reasslen;
553
static u8_t uip_reassflags;
554
#define UIP_REASS_FLAG_LASTFRAG 0x01
555
static u8_t uip_reasstmr;
556
 
557
#define IP_MF   0x20
558
 
559
static u8_t
560
uip_reass(void)
561
{
562
  u16_t offset, len;
563
  u16_t i;
564
 
565
  /* If ip_reasstmr is zero, no packet is present in the buffer, so we
566
     write the IP header of the fragment into the reassembly
567
     buffer. The timer is updated with the maximum age. */
568
  if(uip_reasstmr == 0) {
569
    memcpy(uip_reassbuf, &BUF->vhl, UIP_IPH_LEN);
570
    uip_reasstmr = UIP_REASS_MAXAGE;
571
    uip_reassflags = 0;
572
    /* Clear the bitmap. */
573
    memset(uip_reassbitmap, 0, sizeof(uip_reassbitmap));
574
  }
575
 
576
  /* Check if the incoming fragment matches the one currently present
577
     in the reasembly buffer. If so, we proceed with copying the
578
     fragment into the buffer. */
579
  if(BUF->srcipaddr[0] == FBUF->srcipaddr[0] &&
580
     BUF->srcipaddr[1] == FBUF->srcipaddr[1] &&
581
     BUF->destipaddr[0] == FBUF->destipaddr[0] &&
582
     BUF->destipaddr[1] == FBUF->destipaddr[1] &&
583
     BUF->ipid[0] == FBUF->ipid[0] &&
584
     BUF->ipid[1] == FBUF->ipid[1]) {
585
 
586
    len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4;
587
    offset = (((BUF->ipoffset[0] & 0x3f) << 8) + BUF->ipoffset[1]) * 8;
588
 
589
    /* If the offset or the offset + fragment length overflows the
590
       reassembly buffer, we discard the entire packet. */
591
    if(offset > UIP_REASS_BUFSIZE ||
592
       offset + len > UIP_REASS_BUFSIZE) {
593
      uip_reasstmr = 0;
594
      goto nullreturn;
595
    }
596
 
597
    /* Copy the fragment into the reassembly buffer, at the right
598
       offset. */
599
    memcpy(&uip_reassbuf[UIP_IPH_LEN + offset],
600
           (char *)BUF + (int)((BUF->vhl & 0x0f) * 4),
601
           len);
602
 
603
    /* Update the bitmap. */
604
    if(offset / (8 * 8) == (offset + len) / (8 * 8)) {
605
      /* If the two endpoints are in the same byte, we only update
606
         that byte. */
607
 
608
      uip_reassbitmap[offset / (8 * 8)] |=
609
             bitmap_bits[(offset / 8 ) & 7] &
610
             ~bitmap_bits[((offset + len) / 8 ) & 7];
611
    } else {
612
      /* If the two endpoints are in different bytes, we update the
613
         bytes in the endpoints and fill the stuff inbetween with
614
         0xff. */
615
      uip_reassbitmap[offset / (8 * 8)] |=
616
        bitmap_bits[(offset / 8 ) & 7];
617
      for(i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) {
618
        uip_reassbitmap[i] = 0xff;
619
      }
620
      uip_reassbitmap[(offset + len) / (8 * 8)] |=
621
        ~bitmap_bits[((offset + len) / 8 ) & 7];
622
    }
623
 
624
    /* If this fragment has the More Fragments flag set to zero, we
625
       know that this is the last fragment, so we can calculate the
626
       size of the entire packet. We also set the
627
       IP_REASS_FLAG_LASTFRAG flag to indicate that we have received
628
       the final fragment. */
629
 
630
    if((BUF->ipoffset[0] & IP_MF) == 0) {
631
      uip_reassflags |= UIP_REASS_FLAG_LASTFRAG;
632
      uip_reasslen = offset + len;
633
    }
634
 
635
    /* Finally, we check if we have a full packet in the buffer. We do
636
       this by checking if we have the last fragment and if all bits
637
       in the bitmap are set. */
638
    if(uip_reassflags & UIP_REASS_FLAG_LASTFRAG) {
639
      /* Check all bytes up to and including all but the last byte in
640
         the bitmap. */
641
      for(i = 0; i < uip_reasslen / (8 * 8) - 1; ++i) {
642
        if(uip_reassbitmap[i] != 0xff) {
643
          goto nullreturn;
644
        }
645
      }
646
      /* Check the last byte in the bitmap. It should contain just the
647
         right amount of bits. */
648
      if(uip_reassbitmap[uip_reasslen / (8 * 8)] !=
649
         (u8_t)~bitmap_bits[uip_reasslen / 8 & 7]) {
650
        goto nullreturn;
651
      }
652
 
653
      /* If we have come this far, we have a full packet in the
654
         buffer, so we allocate a pbuf and copy the packet into it. We
655
         also reset the timer. */
656
      uip_reasstmr = 0;
657
      memcpy(BUF, FBUF, uip_reasslen);
658
 
659
      /* Pretend to be a "normal" (i.e., not fragmented) IP packet
660
         from now on. */
661
      BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
662
      BUF->len[0] = uip_reasslen >> 8;
663
      BUF->len[1] = uip_reasslen & 0xff;
664
      BUF->ipchksum = 0;
665
      BUF->ipchksum = ~(uip_ipchksum());
666
 
667
      return uip_reasslen;
668
    }
669
  }
670
 
671
 nullreturn:
672
  return 0;
673
}
674
#endif /* UIP_REASSEMBLY */
675
/*---------------------------------------------------------------------------*/
676
static void
677
uip_add_rcv_nxt(u16_t n)
678
{
679
  uip_add32(uip_conn->rcv_nxt, n);
680
  uip_conn->rcv_nxt[0] = uip_acc32[0];
681
  uip_conn->rcv_nxt[1] = uip_acc32[1];
682
  uip_conn->rcv_nxt[2] = uip_acc32[2];
683
  uip_conn->rcv_nxt[3] = uip_acc32[3];
684
}
685
/*---------------------------------------------------------------------------*/
686
void
687
uip_process(u8_t flag)
688
{
689
  register struct uip_conn *uip_connr = uip_conn;
690
 
691
#if UIP_UDP
692
  if(flag == UIP_UDP_SEND_CONN) {
693
    goto udp_send;
694
  }
695
#endif /* UIP_UDP */
696
 
697
  uip_sappdata = uip_appdata = &uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN];
698
 
699
  /* Check if we were invoked because of a poll request for a
700
     particular connection. */
701
  if(flag == UIP_POLL_REQUEST) {
702
    if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED &&
703
       !uip_outstanding(uip_connr)) {
704
        uip_flags = UIP_POLL;
705
        UIP_APPCALL();
706
        goto appsend;
707
    }
708
    goto drop;
709
 
710
    /* Check if we were invoked because of the perodic timer fireing. */
711
  } else if(flag == UIP_TIMER) {
712
#if UIP_REASSEMBLY
713
    if(uip_reasstmr != 0) {
714
      --uip_reasstmr;
715
    }
716
#endif /* UIP_REASSEMBLY */
717
    /* Increase the initial sequence number. */
718
    if(++iss[3] == 0) {
719
      if(++iss[2] == 0) {
720
        if(++iss[1] == 0) {
721
          ++iss[0];
722
        }
723
      }
724
    }
725
 
726
    /* Reset the length variables. */
727
    uip_len = 0;
728
    uip_slen = 0;
729
 
730
    /* Check if the connection is in a state in which we simply wait
731
       for the connection to time out. If so, we increase the
732
       connection's timer and remove the connection if it times
733
       out. */
734
    if(uip_connr->tcpstateflags == UIP_TIME_WAIT ||
735
       uip_connr->tcpstateflags == UIP_FIN_WAIT_2) {
736
      ++(uip_connr->timer);
737
      if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) {
738
        uip_connr->tcpstateflags = UIP_CLOSED;
739
      }
740
    } else if(uip_connr->tcpstateflags != UIP_CLOSED) {
741
      /* If the connection has outstanding data, we increase the
742
         connection's timer and see if it has reached the RTO value
743
         in which case we retransmit. */
744
      if(uip_outstanding(uip_connr)) {
745
          uip_connr->timer = uip_connr->timer - 1;
746
        if(uip_connr->timer == 0) {
747
          if(uip_connr->nrtx == UIP_MAXRTX ||
748
             ((uip_connr->tcpstateflags == UIP_SYN_SENT ||
749
               uip_connr->tcpstateflags == UIP_SYN_RCVD) &&
750
              uip_connr->nrtx == UIP_MAXSYNRTX)) {
751
            uip_connr->tcpstateflags = UIP_CLOSED;
752
 
753
            /* We call UIP_APPCALL() with uip_flags set to
754
               UIP_TIMEDOUT to inform the application that the
755
               connection has timed out. */
756
            uip_flags = UIP_TIMEDOUT;
757
            UIP_APPCALL();
758
 
759
            /* We also send a reset packet to the remote host. */
760
            BUF->flags = TCP_RST | TCP_ACK;
761
            goto tcp_send_nodata;
762
          }
763
 
764
          /* Exponential backoff. */
765
          uip_connr->timer = UIP_RTO << (uip_connr->nrtx > 4?
766
                                         4:
767
                                         uip_connr->nrtx);
768
          ++(uip_connr->nrtx);
769
 
770
          /* Ok, so we need to retransmit. We do this differently
771
             depending on which state we are in. In ESTABLISHED, we
772
             call upon the application so that it may prepare the
773
             data for the retransmit. In SYN_RCVD, we resend the
774
             SYNACK that we sent earlier and in LAST_ACK we have to
775
             retransmit our FINACK. */
776
          UIP_STAT(++uip_stat.tcp.rexmit);
777
          switch(uip_connr->tcpstateflags & UIP_TS_MASK) {
778
          case UIP_SYN_RCVD:
779
            /* In the SYN_RCVD state, we should retransmit our
780
               SYNACK. */
781
            goto tcp_send_synack;
782
 
783
#if UIP_ACTIVE_OPEN
784
          case UIP_SYN_SENT:
785
            /* In the SYN_SENT state, we retransmit out SYN. */
786
            BUF->flags = 0;
787
            goto tcp_send_syn;
788
#endif /* UIP_ACTIVE_OPEN */
789
 
790
          case UIP_ESTABLISHED:
791
            /* In the ESTABLISHED state, we call upon the application
792
               to do the actual retransmit after which we jump into
793
               the code for sending out the packet (the apprexmit
794
               label). */
795
            uip_flags = UIP_REXMIT;
796
            UIP_APPCALL();
797
            goto apprexmit;
798
 
799
          case UIP_FIN_WAIT_1:
800
          case UIP_CLOSING:
801
          case UIP_LAST_ACK:
802
            /* In all these states we should retransmit a FINACK. */
803
            goto tcp_send_finack;
804
 
805
          }
806
        }
807
      } else if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED) {
808
        /* If there was no need for a retransmission, we poll the
809
           application for new data. */
810
        uip_flags = UIP_POLL;
811
        UIP_APPCALL();
812
        goto appsend;
813
      }
814
    }
815
    goto drop;
816
  }
817
#if UIP_UDP
818
  if(flag == UIP_UDP_TIMER) {
819
    if(uip_udp_conn->lport != 0) {
820
      uip_conn = NULL;
821
      uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
822
      uip_len = uip_slen = 0;
823
      uip_flags = UIP_POLL;
824
      UIP_UDP_APPCALL();
825
      goto udp_send;
826
    } else {
827
      goto drop;
828
    }
829
  }
830
#endif
831
 
832
  /* This is where the input processing starts. */
833
  UIP_STAT(++uip_stat.ip.recv);
834
 
835
  /* Start of IP input header processing code. */
836
 
837
#if UIP_CONF_IPV6
838
  /* Check validity of the IP header. */
839
  if((BUF->vtc & 0xf0) != 0x60)  { /* IP version and header length. */
840
    UIP_STAT(++uip_stat.ip.drop);
841
    UIP_STAT(++uip_stat.ip.vhlerr);
842
    UIP_LOG("ipv6: invalid version.");
843
    goto drop;
844
  }
845
#else /* UIP_CONF_IPV6 */
846
  /* Check validity of the IP header. */
847
  if(BUF->vhl != 0x45)  { /* IP version and header length. */
848
    UIP_STAT(++uip_stat.ip.drop);
849
    UIP_STAT(++uip_stat.ip.vhlerr);
850
    UIP_LOG("ip: invalid version or header length.");
851
    goto drop;
852
  }
853
#endif /* UIP_CONF_IPV6 */
854
 
855
  /* Check the size of the packet. If the size reported to us in
856
     uip_len is smaller the size reported in the IP header, we assume
857
     that the packet has been corrupted in transit. If the size of
858
     uip_len is larger than the size reported in the IP packet header,
859
     the packet has been padded and we set uip_len to the correct
860
     value.. */
861
 
862
  if((BUF->len[0] << 8) + BUF->len[1] <= uip_len) {
863
    uip_len = (BUF->len[0] << 8) + BUF->len[1];
864
#if UIP_CONF_IPV6
865
    uip_len += 40; /* The length reported in the IPv6 header is the
866
                      length of the payload that follows the
867
                      header. However, uIP uses the uip_len variable
868
                      for holding the size of the entire packet,
869
                      including the IP header. For IPv4 this is not a
870
                      problem as the length field in the IPv4 header
871
                      contains the length of the entire packet. But
872
                      for IPv6 we need to add the size of the IPv6
873
                      header (40 bytes). */
874
#endif /* UIP_CONF_IPV6 */
875
  } else {
876
    UIP_LOG("ip: packet shorter than reported in IP header.");
877
    goto drop;
878
  }
879
 
880
#if !UIP_CONF_IPV6
881
  /* Check the fragment flag. */
882
  if((BUF->ipoffset[0] & 0x3f) != 0 ||
883
     BUF->ipoffset[1] != 0) {
884
#if UIP_REASSEMBLY
885
    uip_len = uip_reass();
886
    if(uip_len == 0) {
887
      goto drop;
888
    }
889
#else /* UIP_REASSEMBLY */
890
    UIP_STAT(++uip_stat.ip.drop);
891
    UIP_STAT(++uip_stat.ip.fragerr);
892
    UIP_LOG("ip: fragment dropped.");
893
    goto drop;
894
#endif /* UIP_REASSEMBLY */
895
  }
896
#endif /* UIP_CONF_IPV6 */
897
 
898
  if(uip_ipaddr_cmp(uip_hostaddr, all_zeroes_addr)) {
899
    /* If we are configured to use ping IP address configuration and
900
       hasn't been assigned an IP address yet, we accept all ICMP
901
       packets. */
902
#if UIP_PINGADDRCONF && !UIP_CONF_IPV6
903
    if(BUF->proto == UIP_PROTO_ICMP) {
904
      UIP_LOG("ip: possible ping config packet received.");
905
      goto icmp_input;
906
    } else {
907
      UIP_LOG("ip: packet dropped since no address assigned.");
908
      goto drop;
909
    }
910
#endif /* UIP_PINGADDRCONF */
911
 
912
  } else {
913
    /* If IP broadcast support is configured, we check for a broadcast
914
       UDP packet, which may be destined to us. */
915
#if UIP_BROADCAST
916
    DEBUG_PRINTF("UDP IP checksum 0x%04x\n", uip_ipchksum());
917
    if(BUF->proto == UIP_PROTO_UDP &&
918
       uip_ipaddr_cmp(BUF->destipaddr, all_ones_addr)
919
       /*&&
920
         uip_ipchksum() == 0xffff*/) {
921
      goto udp_input;
922
    }
923
#endif /* UIP_BROADCAST */
924
 
925
    /* Check if the packet is destined for our IP address. */
926
#if !UIP_CONF_IPV6
927
    if(!uip_ipaddr_cmp(BUF->destipaddr, uip_hostaddr)) {
928
      UIP_STAT(++uip_stat.ip.drop);
929
      goto drop;
930
    }
931
#else /* UIP_CONF_IPV6 */
932
    /* For IPv6, packet reception is a little trickier as we need to
933
       make sure that we listen to certain multicast addresses (all
934
       hosts multicast address, and the solicited-node multicast
935
       address) as well. However, we will cheat here and accept all
936
       multicast packets that are sent to the ff02::/16 addresses. */
937
    if(!uip_ipaddr_cmp(BUF->destipaddr, uip_hostaddr) &&
938
       BUF->destipaddr[0] != HTONS(0xff02)) {
939
      UIP_STAT(++uip_stat.ip.drop);
940
      goto drop;
941
    }
942
#endif /* UIP_CONF_IPV6 */
943
  }
944
 
945
#if !UIP_CONF_IPV6
946
  if(uip_ipchksum() != 0xffff) { /* Compute and check the IP header
947
                                    checksum. */
948
    UIP_STAT(++uip_stat.ip.drop);
949
    UIP_STAT(++uip_stat.ip.chkerr);
950
    UIP_LOG("ip: bad checksum.");
951
    goto drop;
952
  }
953
#endif /* UIP_CONF_IPV6 */
954
 
955
  if(BUF->proto == UIP_PROTO_TCP) { /* Check for TCP packet. If so,
956
                                       proceed with TCP input
957
                                       processing. */
958
    goto tcp_input;
959
  }
960
 
961
#if UIP_UDP
962
  if(BUF->proto == UIP_PROTO_UDP) {
963
    goto udp_input;
964
  }
965
#endif /* UIP_UDP */
966
 
967
#if !UIP_CONF_IPV6
968
  /* ICMPv4 processing code follows. */
969
  if(BUF->proto != UIP_PROTO_ICMP) { /* We only allow ICMP packets from
970
                                        here. */
971
    UIP_STAT(++uip_stat.ip.drop);
972
    UIP_STAT(++uip_stat.ip.protoerr);
973
    UIP_LOG("ip: neither tcp nor icmp.");
974
    goto drop;
975
  }
976
 
977
#if UIP_PINGADDRCONF
978
 icmp_input:
979
#endif /* UIP_PINGADDRCONF */
980
  UIP_STAT(++uip_stat.icmp.recv);
981
 
982
  /* ICMP echo (i.e., ping) processing. This is simple, we only change
983
     the ICMP type from ECHO to ECHO_REPLY and adjust the ICMP
984
     checksum before we return the packet. */
985
  if(ICMPBUF->type != ICMP_ECHO) {
986
    UIP_STAT(++uip_stat.icmp.drop);
987
    UIP_STAT(++uip_stat.icmp.typeerr);
988
    UIP_LOG("icmp: not icmp echo.");
989
    goto drop;
990
  }
991
 
992
  /* If we are configured to use ping IP address assignment, we use
993
     the destination IP address of this ping packet and assign it to
994
     ourself. */
995
#if UIP_PINGADDRCONF
996
  if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) {
997
    uip_hostaddr[0] = BUF->destipaddr[0];
998
    uip_hostaddr[1] = BUF->destipaddr[1];
999
  }
1000
#endif /* UIP_PINGADDRCONF */
1001
 
1002
  ICMPBUF->type = ICMP_ECHO_REPLY;
1003
 
1004
  if(ICMPBUF->icmpchksum >= HTONS(0xffff - (ICMP_ECHO << 8))) {
1005
    ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8) + 1;
1006
  } else {
1007
    ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8);
1008
  }
1009
 
1010
  /* Swap IP addresses. */
1011
  uip_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
1012
  uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
1013
 
1014
  UIP_STAT(++uip_stat.icmp.sent);
1015
  goto send;
1016
 
1017
  /* End of IPv4 input header processing code. */
1018
#else /* !UIP_CONF_IPV6 */
1019
 
1020
  /* This is IPv6 ICMPv6 processing code. */
1021
  DEBUG_PRINTF("icmp6_input: length %d\n", uip_len);
1022
 
1023
  if(BUF->proto != UIP_PROTO_ICMP6) { /* We only allow ICMPv6 packets from
1024
                                         here. */
1025
    UIP_STAT(++uip_stat.ip.drop);
1026
    UIP_STAT(++uip_stat.ip.protoerr);
1027
    UIP_LOG("ip: neither tcp nor icmp6.");
1028
    goto drop;
1029
  }
1030
 
1031
  UIP_STAT(++uip_stat.icmp.recv);
1032
 
1033
  /* If we get a neighbor solicitation for our address we should send
1034
     a neighbor advertisement message back. */
1035
  if(ICMPBUF->type == ICMP6_NEIGHBOR_SOLICITATION) {
1036
    if(uip_ipaddr_cmp(ICMPBUF->icmp6data, uip_hostaddr)) {
1037
 
1038
      if(ICMPBUF->options[0] == ICMP6_OPTION_SOURCE_LINK_ADDRESS) {
1039
        /* Save the sender's address in our neighbor list. */
1040
        uip_neighbor_add(ICMPBUF->srcipaddr, &(ICMPBUF->options[2]));
1041
      }
1042
 
1043
      /* We should now send a neighbor advertisement back to where the
1044
         neighbor solicication came from. */
1045
      ICMPBUF->type = ICMP6_NEIGHBOR_ADVERTISEMENT;
1046
      ICMPBUF->flags = ICMP6_FLAG_S; /* Solicited flag. */
1047
 
1048
      ICMPBUF->reserved1 = ICMPBUF->reserved2 = ICMPBUF->reserved3 = 0;
1049
 
1050
      uip_ipaddr_copy(ICMPBUF->destipaddr, ICMPBUF->srcipaddr);
1051
      uip_ipaddr_copy(ICMPBUF->srcipaddr, uip_hostaddr);
1052
      ICMPBUF->options[0] = ICMP6_OPTION_TARGET_LINK_ADDRESS;
1053
      ICMPBUF->options[1] = 1;  /* Options length, 1 = 8 bytes. */
1054
      memcpy(&(ICMPBUF->options[2]), &uip_ethaddr, sizeof(uip_ethaddr));
1055
      ICMPBUF->icmpchksum = 0;
1056
      ICMPBUF->icmpchksum = ~uip_icmp6chksum();
1057
      goto send;
1058
 
1059
    }
1060
    goto drop;
1061
  } else if(ICMPBUF->type == ICMP6_ECHO) {
1062
    /* ICMP echo (i.e., ping) processing. This is simple, we only
1063
       change the ICMP type from ECHO to ECHO_REPLY and update the
1064
       ICMP checksum before we return the packet. */
1065
 
1066
    ICMPBUF->type = ICMP6_ECHO_REPLY;
1067
 
1068
    uip_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
1069
    uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
1070
    ICMPBUF->icmpchksum = 0;
1071
    ICMPBUF->icmpchksum = ~uip_icmp6chksum();
1072
 
1073
    UIP_STAT(++uip_stat.icmp.sent);
1074
    goto send;
1075
  } else {
1076
    DEBUG_PRINTF("Unknown icmp6 message type %d\n", ICMPBUF->type);
1077
    UIP_STAT(++uip_stat.icmp.drop);
1078
    UIP_STAT(++uip_stat.icmp.typeerr);
1079
    UIP_LOG("icmp: unknown ICMP message.");
1080
    goto drop;
1081
  }
1082
 
1083
  /* End of IPv6 ICMP processing. */
1084
 
1085
#endif /* !UIP_CONF_IPV6 */
1086
 
1087
#if UIP_UDP
1088
  /* UDP input processing. */
1089
 udp_input:
1090
  /* UDP processing is really just a hack. We don't do anything to the
1091
     UDP/IP headers, but let the UDP application do all the hard
1092
     work. If the application sets uip_slen, it has a packet to
1093
     send. */
1094
#if UIP_UDP_CHECKSUMS
1095
  uip_len = uip_len - UIP_IPUDPH_LEN;
1096
  uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
1097
  if(UDPBUF->udpchksum != 0 && uip_udpchksum() != 0xffff) {
1098
    UIP_STAT(++uip_stat.udp.drop);
1099
    UIP_STAT(++uip_stat.udp.chkerr);
1100
    UIP_LOG("udp: bad checksum.");
1101
    goto drop;
1102
  }
1103
#else /* UIP_UDP_CHECKSUMS */
1104
  uip_len = uip_len - UIP_IPUDPH_LEN;
1105
#endif /* UIP_UDP_CHECKSUMS */
1106
 
1107
  /* Demultiplex this UDP packet between the UDP "connections". */
1108
  for(uip_udp_conn = &uip_udp_conns[0];
1109
      uip_udp_conn < &uip_udp_conns[UIP_UDP_CONNS];
1110
      ++uip_udp_conn) {
1111
    /* If the local UDP port is non-zero, the connection is considered
1112
       to be used. If so, the local port number is checked against the
1113
       destination port number in the received packet. If the two port
1114
       numbers match, the remote port number is checked if the
1115
       connection is bound to a remote port. Finally, if the
1116
       connection is bound to a remote IP address, the source IP
1117
       address of the packet is checked. */
1118
    if(uip_udp_conn->lport != 0 &&
1119
       UDPBUF->destport == uip_udp_conn->lport &&
1120
       (uip_udp_conn->rport == 0 ||
1121
        UDPBUF->srcport == uip_udp_conn->rport) &&
1122
       (uip_ipaddr_cmp(uip_udp_conn->ripaddr, all_zeroes_addr) ||
1123
        uip_ipaddr_cmp(uip_udp_conn->ripaddr, all_ones_addr) ||
1124
        uip_ipaddr_cmp(BUF->srcipaddr, uip_udp_conn->ripaddr))) {
1125
      goto udp_found;
1126
    }
1127
  }
1128
  UIP_LOG("udp: no matching connection found");
1129
  goto drop;
1130
 
1131
 udp_found:
1132
  UIP_STAT(++uip_stat.udp.recv);
1133
  uip_conn = NULL;
1134
  uip_flags = UIP_NEWDATA;
1135
  uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
1136
  uip_slen = 0;
1137
  UIP_UDP_APPCALL();
1138
 udp_send:
1139
  if(uip_slen == 0) {
1140
    goto drop;
1141
  }
1142
  uip_len = uip_slen + UIP_IPUDPH_LEN;
1143
 
1144
#if UIP_CONF_IPV6
1145
  /* For IPv6, the IP length field does not include the IPv6 IP header
1146
     length. */
1147
  BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
1148
  BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
1149
#else /* UIP_CONF_IPV6 */
1150
  BUF->len[0] = (uip_len >> 8);
1151
  BUF->len[1] = (uip_len & 0xff);
1152
#endif /* UIP_CONF_IPV6 */
1153
 
1154
  BUF->ttl = uip_udp_conn->ttl;
1155
  BUF->proto = UIP_PROTO_UDP;
1156
 
1157
  UDPBUF->udplen = HTONS(uip_slen + UIP_UDPH_LEN);
1158
  UDPBUF->udpchksum = 0;
1159
 
1160
  BUF->srcport  = uip_udp_conn->lport;
1161
  BUF->destport = uip_udp_conn->rport;
1162
 
1163
  uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
1164
  uip_ipaddr_copy(BUF->destipaddr, uip_udp_conn->ripaddr);
1165
 
1166
  uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPTCPH_LEN];
1167
 
1168
#if UIP_UDP_CHECKSUMS
1169
  /* Calculate UDP checksum. */
1170
  UDPBUF->udpchksum = ~(uip_udpchksum());
1171
  if(UDPBUF->udpchksum == 0) {
1172
    UDPBUF->udpchksum = 0xffff;
1173
  }
1174
#endif /* UIP_UDP_CHECKSUMS */
1175
  UIP_STAT(++uip_stat.udp.sent);
1176
  goto ip_send_nolen;
1177
#endif /* UIP_UDP */
1178
 
1179
  /* TCP input processing. */
1180
 tcp_input:
1181
  UIP_STAT(++uip_stat.tcp.recv);
1182
 
1183
  /* Start of TCP input header processing code. */
1184
 
1185
  if(uip_tcpchksum() != 0xffff) {   /* Compute and check the TCP
1186
                                       checksum. */
1187
    UIP_STAT(++uip_stat.tcp.drop);
1188
    UIP_STAT(++uip_stat.tcp.chkerr);
1189
    UIP_LOG("tcp: bad checksum.");
1190
    goto drop;
1191
  }
1192
 
1193
 
1194
  /* Demultiplex this segment. */
1195
  /* First check any active connections. */
1196
  for(uip_connr = &uip_conns[0]; uip_connr <= &uip_conns[UIP_CONNS - 1];
1197
      ++uip_connr) {
1198
    if(uip_connr->tcpstateflags != UIP_CLOSED &&
1199
       BUF->destport == uip_connr->lport &&
1200
       BUF->srcport == uip_connr->rport &&
1201
       uip_ipaddr_cmp(BUF->srcipaddr, uip_connr->ripaddr)) {
1202
      goto found;
1203
    }
1204
  }
1205
 
1206
  /* If we didn't find and active connection that expected the packet,
1207
     either this packet is an old duplicate, or this is a SYN packet
1208
     destined for a connection in LISTEN. If the SYN flag isn't set,
1209
     it is an old packet and we send a RST. */
1210
  if((BUF->flags & TCP_CTL) != TCP_SYN) {
1211
    goto reset;
1212
  }
1213
 
1214
  tmp16 = BUF->destport;
1215
  /* Next, check listening connections. */
1216
  for(c = 0; c < UIP_LISTENPORTS; ++c) {
1217
    if(tmp16 == uip_listenports[c])
1218
      goto found_listen;
1219
  }
1220
 
1221
  /* No matching connection found, so we send a RST packet. */
1222
  UIP_STAT(++uip_stat.tcp.synrst);
1223
 reset:
1224
 
1225
  /* We do not send resets in response to resets. */
1226
  if(BUF->flags & TCP_RST) {
1227
    goto drop;
1228
  }
1229
 
1230
  UIP_STAT(++uip_stat.tcp.rst);
1231
 
1232
  BUF->flags = TCP_RST | TCP_ACK;
1233
  uip_len = UIP_IPTCPH_LEN;
1234
  BUF->tcpoffset = 5 << 4;
1235
 
1236
  /* Flip the seqno and ackno fields in the TCP header. */
1237
  c = BUF->seqno[3];
1238
  BUF->seqno[3] = BUF->ackno[3];
1239
  BUF->ackno[3] = c;
1240
 
1241
  c = BUF->seqno[2];
1242
  BUF->seqno[2] = BUF->ackno[2];
1243
  BUF->ackno[2] = c;
1244
 
1245
  c = BUF->seqno[1];
1246
  BUF->seqno[1] = BUF->ackno[1];
1247
  BUF->ackno[1] = c;
1248
 
1249
  c = BUF->seqno[0];
1250
  BUF->seqno[0] = BUF->ackno[0];
1251
  BUF->ackno[0] = c;
1252
 
1253
  /* We also have to increase the sequence number we are
1254
     acknowledging. If the least significant byte overflowed, we need
1255
     to propagate the carry to the other bytes as well. */
1256
  if(++BUF->ackno[3] == 0) {
1257
    if(++BUF->ackno[2] == 0) {
1258
      if(++BUF->ackno[1] == 0) {
1259
        ++BUF->ackno[0];
1260
      }
1261
    }
1262
  }
1263
 
1264
  /* Swap port numbers. */
1265
  tmp16 = BUF->srcport;
1266
  BUF->srcport = BUF->destport;
1267
  BUF->destport = tmp16;
1268
 
1269
  /* Swap IP addresses. */
1270
  uip_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
1271
  uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
1272
 
1273
  /* And send out the RST packet! */
1274
  goto tcp_send_noconn;
1275
 
1276
  /* This label will be jumped to if we matched the incoming packet
1277
     with a connection in LISTEN. In that case, we should create a new
1278
     connection and send a SYNACK in return. */
1279
 found_listen:
1280
  /* First we check if there are any connections avaliable. Unused
1281
     connections are kept in the same table as used connections, but
1282
     unused ones have the tcpstate set to CLOSED. Also, connections in
1283
     TIME_WAIT are kept track of and we'll use the oldest one if no
1284
     CLOSED connections are found. Thanks to Eddie C. Dost for a very
1285
     nice algorithm for the TIME_WAIT search. */
1286
  uip_connr = 0;
1287
  for(c = 0; c < UIP_CONNS; ++c) {
1288
    if(uip_conns[c].tcpstateflags == UIP_CLOSED) {
1289
      uip_connr = &uip_conns[c];
1290
      break;
1291
    }
1292
    if(uip_conns[c].tcpstateflags == UIP_TIME_WAIT) {
1293
      if(uip_connr == 0 ||
1294
         uip_conns[c].timer > uip_connr->timer) {
1295
        uip_connr = &uip_conns[c];
1296
      }
1297
    }
1298
  }
1299
 
1300
  if(uip_connr == 0) {
1301
    /* All connections are used already, we drop packet and hope that
1302
       the remote end will retransmit the packet at a time when we
1303
       have more spare connections. */
1304
    UIP_STAT(++uip_stat.tcp.syndrop);
1305
    UIP_LOG("tcp: found no unused connections.");
1306
    goto drop;
1307
  }
1308
  uip_conn = uip_connr;
1309
 
1310
  /* Fill in the necessary fields for the new connection. */
1311
  uip_connr->rto = uip_connr->timer = UIP_RTO;
1312
  uip_connr->sa = 0;
1313
  uip_connr->sv = 4;
1314
  uip_connr->nrtx = 0;
1315
  uip_connr->lport = BUF->destport;
1316
  uip_connr->rport = BUF->srcport;
1317
  uip_ipaddr_copy(uip_connr->ripaddr, BUF->srcipaddr);
1318
  uip_connr->tcpstateflags = UIP_SYN_RCVD;
1319
 
1320
  uip_connr->snd_nxt[0] = iss[0];
1321
  uip_connr->snd_nxt[1] = iss[1];
1322
  uip_connr->snd_nxt[2] = iss[2];
1323
  uip_connr->snd_nxt[3] = iss[3];
1324
  uip_connr->len = 1;
1325
 
1326
  /* rcv_nxt should be the seqno from the incoming packet + 1. */
1327
  uip_connr->rcv_nxt[3] = BUF->seqno[3];
1328
  uip_connr->rcv_nxt[2] = BUF->seqno[2];
1329
  uip_connr->rcv_nxt[1] = BUF->seqno[1];
1330
  uip_connr->rcv_nxt[0] = BUF->seqno[0];
1331
  uip_add_rcv_nxt(1);
1332
 
1333
  /* Parse the TCP MSS option, if present. */
1334
  if((BUF->tcpoffset & 0xf0) > 0x50) {
1335
    for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) {
1336
      opt = uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + c];
1337
      if(opt == TCP_OPT_END) {
1338
        /* End of options. */
1339
        break;
1340
      } else if(opt == TCP_OPT_NOOP) {
1341
        ++c;
1342
        /* NOP option. */
1343
      } else if(opt == TCP_OPT_MSS &&
1344
                uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) {
1345
        /* An MSS option with the right option length. */
1346
        tmp16 = ((u16_t)uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) |
1347
          (u16_t)uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + 3 + c];
1348
        uip_connr->initialmss = uip_connr->mss =
1349
          tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
1350
 
1351
        /* And we are done processing options. */
1352
        break;
1353
      } else {
1354
        /* All other options have a length field, so that we easily
1355
           can skip past them. */
1356
        if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
1357
          /* If the length field is zero, the options are malformed
1358
             and we don't process them further. */
1359
          break;
1360
        }
1361
        c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
1362
      }
1363
    }
1364
  }
1365
 
1366
  /* Our response will be a SYNACK. */
1367
#if UIP_ACTIVE_OPEN
1368
 tcp_send_synack:
1369
  BUF->flags = TCP_ACK;
1370
 
1371
 tcp_send_syn:
1372
  BUF->flags |= TCP_SYN;
1373
#else /* UIP_ACTIVE_OPEN */
1374
 tcp_send_synack:
1375
  BUF->flags = TCP_SYN | TCP_ACK;
1376
#endif /* UIP_ACTIVE_OPEN */
1377
 
1378
  /* We send out the TCP Maximum Segment Size option with our
1379
     SYNACK. */
1380
  BUF->optdata[0] = TCP_OPT_MSS;
1381
  BUF->optdata[1] = TCP_OPT_MSS_LEN;
1382
  BUF->optdata[2] = (UIP_TCP_MSS) / 256;
1383
  BUF->optdata[3] = (UIP_TCP_MSS) & 255;
1384
  uip_len = UIP_IPTCPH_LEN + TCP_OPT_MSS_LEN;
1385
  BUF->tcpoffset = ((UIP_TCPH_LEN + TCP_OPT_MSS_LEN) / 4) << 4;
1386
  goto tcp_send;
1387
 
1388
  /* This label will be jumped to if we found an active connection. */
1389
 found:
1390
  uip_conn = uip_connr;
1391
  uip_flags = 0;
1392
  /* We do a very naive form of TCP reset processing; we just accept
1393
     any RST and kill our connection. We should in fact check if the
1394
     sequence number of this reset is wihtin our advertised window
1395
     before we accept the reset. */
1396
  if(BUF->flags & TCP_RST) {
1397
    uip_connr->tcpstateflags = UIP_CLOSED;
1398
    UIP_LOG("tcp: got reset, aborting connection.");
1399
    uip_flags = UIP_ABORT;
1400
    UIP_APPCALL();
1401
    goto drop;
1402
  }
1403
  /* Calculated the length of the data, if the application has sent
1404
     any data to us. */
1405
  c = (BUF->tcpoffset >> 4) << 2;
1406
  /* uip_len will contain the length of the actual TCP data. This is
1407
     calculated by subtracing the length of the TCP header (in
1408
     c) and the length of the IP header (20 bytes). */
1409
  uip_len = uip_len - c - UIP_IPH_LEN;
1410
 
1411
  /* First, check if the sequence number of the incoming packet is
1412
     what we're expecting next. If not, we send out an ACK with the
1413
     correct numbers in. */
1414
  if(!(((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_SYN_SENT) &&
1415
       ((BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)))) {
1416
    if((uip_len > 0 || ((BUF->flags & (TCP_SYN | TCP_FIN)) != 0)) &&
1417
       (BUF->seqno[0] != uip_connr->rcv_nxt[0] ||
1418
        BUF->seqno[1] != uip_connr->rcv_nxt[1] ||
1419
        BUF->seqno[2] != uip_connr->rcv_nxt[2] ||
1420
        BUF->seqno[3] != uip_connr->rcv_nxt[3])) {
1421
      goto tcp_send_ack;
1422
    }
1423
  }
1424
 
1425
  /* Next, check if the incoming segment acknowledges any outstanding
1426
     data. If so, we update the sequence number, reset the length of
1427
     the outstanding data, calculate RTT estimations, and reset the
1428
     retransmission timer. */
1429
  if((BUF->flags & TCP_ACK) && uip_outstanding(uip_connr)) {
1430
    uip_add32(uip_connr->snd_nxt, uip_connr->len);
1431
 
1432
    if(BUF->ackno[0] == uip_acc32[0] &&
1433
       BUF->ackno[1] == uip_acc32[1] &&
1434
       BUF->ackno[2] == uip_acc32[2] &&
1435
       BUF->ackno[3] == uip_acc32[3]) {
1436
      /* Update sequence number. */
1437
      uip_connr->snd_nxt[0] = uip_acc32[0];
1438
      uip_connr->snd_nxt[1] = uip_acc32[1];
1439
      uip_connr->snd_nxt[2] = uip_acc32[2];
1440
      uip_connr->snd_nxt[3] = uip_acc32[3];
1441
 
1442
 
1443
      /* Do RTT estimation, unless we have done retransmissions. */
1444
      if(uip_connr->nrtx == 0) {
1445
        signed char m;
1446
        m = uip_connr->rto - uip_connr->timer;
1447
        /* This is taken directly from VJs original code in his paper */
1448
        m = m - (uip_connr->sa >> 3);
1449
        uip_connr->sa += m;
1450
        if(m < 0) {
1451
          m = -m;
1452
        }
1453
        m = m - (uip_connr->sv >> 2);
1454
        uip_connr->sv += m;
1455
        uip_connr->rto = (uip_connr->sa >> 3) + uip_connr->sv;
1456
 
1457
      }
1458
      /* Set the acknowledged flag. */
1459
      uip_flags = UIP_ACKDATA;
1460
      /* Reset the retransmission timer. */
1461
      uip_connr->timer = uip_connr->rto;
1462
 
1463
      /* Reset length of outstanding data. */
1464
      uip_connr->len = 0;
1465
    }
1466
 
1467
  }
1468
 
1469
  /* Do different things depending on in what state the connection is. */
1470
  switch(uip_connr->tcpstateflags & UIP_TS_MASK) {
1471
    /* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not
1472
        implemented, since we force the application to close when the
1473
        peer sends a FIN (hence the application goes directly from
1474
        ESTABLISHED to LAST_ACK). */
1475
  case UIP_SYN_RCVD:
1476
    /* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and
1477
       we are waiting for an ACK that acknowledges the data we sent
1478
       out the last time. Therefore, we want to have the UIP_ACKDATA
1479
       flag set. If so, we enter the ESTABLISHED state. */
1480
    if(uip_flags & UIP_ACKDATA) {
1481
      uip_connr->tcpstateflags = UIP_ESTABLISHED;
1482
      uip_flags = UIP_CONNECTED;
1483
      uip_connr->len = 0;
1484
      if(uip_len > 0) {
1485
        uip_flags |= UIP_NEWDATA;
1486
        uip_add_rcv_nxt(uip_len);
1487
      }
1488
      uip_slen = 0;
1489
      UIP_APPCALL();
1490
      goto appsend;
1491
    }
1492
    goto drop;
1493
#if UIP_ACTIVE_OPEN
1494
  case UIP_SYN_SENT:
1495
    /* In SYN_SENT, we wait for a SYNACK that is sent in response to
1496
       our SYN. The rcv_nxt is set to sequence number in the SYNACK
1497
       plus one, and we send an ACK. We move into the ESTABLISHED
1498
       state. */
1499
    if((uip_flags & UIP_ACKDATA) &&
1500
       (BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)) {
1501
 
1502
      /* Parse the TCP MSS option, if present. */
1503
      if((BUF->tcpoffset & 0xf0) > 0x50) {
1504
        for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) {
1505
          opt = uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + c];
1506
          if(opt == TCP_OPT_END) {
1507
            /* End of options. */
1508
            break;
1509
          } else if(opt == TCP_OPT_NOOP) {
1510
            ++c;
1511
            /* NOP option. */
1512
          } else if(opt == TCP_OPT_MSS &&
1513
                    uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) {
1514
            /* An MSS option with the right option length. */
1515
            tmp16 = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) |
1516
              uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + c];
1517
            uip_connr->initialmss =
1518
              uip_connr->mss = tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
1519
 
1520
            /* And we are done processing options. */
1521
            break;
1522
          } else {
1523
            /* All other options have a length field, so that we easily
1524
               can skip past them. */
1525
            if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
1526
              /* If the length field is zero, the options are malformed
1527
                 and we don't process them further. */
1528
              break;
1529
            }
1530
            c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
1531
          }
1532
        }
1533
      }
1534
      uip_connr->tcpstateflags = UIP_ESTABLISHED;
1535
      uip_connr->rcv_nxt[0] = BUF->seqno[0];
1536
      uip_connr->rcv_nxt[1] = BUF->seqno[1];
1537
      uip_connr->rcv_nxt[2] = BUF->seqno[2];
1538
      uip_connr->rcv_nxt[3] = BUF->seqno[3];
1539
      uip_add_rcv_nxt(1);
1540
      uip_flags = UIP_CONNECTED | UIP_NEWDATA;
1541
      uip_connr->len = 0;
1542
      uip_len = 0;
1543
      uip_slen = 0;
1544
      UIP_APPCALL();
1545
      goto appsend;
1546
    }
1547
    /* Inform the application that the connection failed */
1548
    uip_flags = UIP_ABORT;
1549
    UIP_APPCALL();
1550
    /* The connection is closed after we send the RST */
1551
    uip_conn->tcpstateflags = UIP_CLOSED;
1552
    goto reset;
1553
#endif /* UIP_ACTIVE_OPEN */
1554
 
1555
  case UIP_ESTABLISHED:
1556
    /* In the ESTABLISHED state, we call upon the application to feed
1557
    data into the uip_buf. If the UIP_ACKDATA flag is set, the
1558
    application should put new data into the buffer, otherwise we are
1559
    retransmitting an old segment, and the application should put that
1560
    data into the buffer.
1561
 
1562
    If the incoming packet is a FIN, we should close the connection on
1563
    this side as well, and we send out a FIN and enter the LAST_ACK
1564
    state. We require that there is no outstanding data; otherwise the
1565
    sequence numbers will be screwed up. */
1566
 
1567
    if(BUF->flags & TCP_FIN && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
1568
      if(uip_outstanding(uip_connr)) {
1569
        goto drop;
1570
      }
1571
      uip_add_rcv_nxt(1 + uip_len);
1572
      uip_flags |= UIP_CLOSE;
1573
      if(uip_len > 0) {
1574
        uip_flags |= UIP_NEWDATA;
1575
      }
1576
      UIP_APPCALL();
1577
      uip_connr->len = 1;
1578
      uip_connr->tcpstateflags = UIP_LAST_ACK;
1579
      uip_connr->nrtx = 0;
1580
    tcp_send_finack:
1581
      BUF->flags = TCP_FIN | TCP_ACK;
1582
      goto tcp_send_nodata;
1583
    }
1584
 
1585
    /* Check the URG flag. If this is set, the segment carries urgent
1586
       data that we must pass to the application. */
1587
    if((BUF->flags & TCP_URG) != 0) {
1588
#if UIP_URGDATA > 0
1589
      uip_urglen = (BUF->urgp[0] << 8) | BUF->urgp[1];
1590
      if(uip_urglen > uip_len) {
1591
        /* There is more urgent data in the next segment to come. */
1592
        uip_urglen = uip_len;
1593
      }
1594
      uip_add_rcv_nxt(uip_urglen);
1595
      uip_len -= uip_urglen;
1596
      uip_urgdata = uip_appdata;
1597
      uip_appdata += uip_urglen;
1598
    } else {
1599
      uip_urglen = 0;
1600
#else /* UIP_URGDATA > 0 */
1601
      uip_appdata = ((char *)uip_appdata) + ((BUF->urgp[0] << 8) | BUF->urgp[1]);
1602
      uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1];
1603
#endif /* UIP_URGDATA > 0 */
1604
    }
1605
 
1606
    /* If uip_len > 0 we have TCP data in the packet, and we flag this
1607
       by setting the UIP_NEWDATA flag and update the sequence number
1608
       we acknowledge. If the application has stopped the dataflow
1609
       using uip_stop(), we must not accept any data packets from the
1610
       remote host. */
1611
    if(uip_len > 0 && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
1612
      uip_flags |= UIP_NEWDATA;
1613
      uip_add_rcv_nxt(uip_len);
1614
    }
1615
 
1616
    /* Check if the available buffer space advertised by the other end
1617
       is smaller than the initial MSS for this connection. If so, we
1618
       set the current MSS to the window size to ensure that the
1619
       application does not send more data than the other end can
1620
       handle.
1621
 
1622
       If the remote host advertises a zero window, we set the MSS to
1623
       the initial MSS so that the application will send an entire MSS
1624
       of data. This data will not be acknowledged by the receiver,
1625
       and the application will retransmit it. This is called the
1626
       "persistent timer" and uses the retransmission mechanim.
1627
    */
1628
    tmp16 = ((u16_t)BUF->wnd[0] << 8) + (u16_t)BUF->wnd[1];
1629
    if(tmp16 > uip_connr->initialmss ||
1630
       tmp16 == 0) {
1631
      tmp16 = uip_connr->initialmss;
1632
    }
1633
    uip_connr->mss = tmp16;
1634
 
1635
    /* If this packet constitutes an ACK for outstanding data (flagged
1636
       by the UIP_ACKDATA flag, we should call the application since it
1637
       might want to send more data. If the incoming packet had data
1638
       from the peer (as flagged by the UIP_NEWDATA flag), the
1639
       application must also be notified.
1640
 
1641
       When the application is called, the global variable uip_len
1642
       contains the length of the incoming data. The application can
1643
       access the incoming data through the global pointer
1644
       uip_appdata, which usually points UIP_IPTCPH_LEN + UIP_LLH_LEN
1645
       bytes into the uip_buf array.
1646
 
1647
       If the application wishes to send any data, this data should be
1648
       put into the uip_appdata and the length of the data should be
1649
       put into uip_len. If the application don't have any data to
1650
       send, uip_len must be set to 0. */
1651
    if(uip_flags & (UIP_NEWDATA | UIP_ACKDATA)) {
1652
      uip_slen = 0;
1653
      UIP_APPCALL();
1654
 
1655
    appsend:
1656
 
1657
      if(uip_flags & UIP_ABORT) {
1658
        uip_slen = 0;
1659
        uip_connr->tcpstateflags = UIP_CLOSED;
1660
        BUF->flags = TCP_RST | TCP_ACK;
1661
        goto tcp_send_nodata;
1662
      }
1663
 
1664
      if(uip_flags & UIP_CLOSE) {
1665
        uip_slen = 0;
1666
        uip_connr->len = 1;
1667
        uip_connr->tcpstateflags = UIP_FIN_WAIT_1;
1668
        uip_connr->nrtx = 0;
1669
        BUF->flags = TCP_FIN | TCP_ACK;
1670
        goto tcp_send_nodata;
1671
      }
1672
 
1673
      /* If uip_slen > 0, the application has data to be sent. */
1674
      if(uip_slen > 0) {
1675
 
1676
        /* If the connection has acknowledged data, the contents of
1677
           the ->len variable should be discarded. */
1678
        if((uip_flags & UIP_ACKDATA) != 0) {
1679
          uip_connr->len = 0;
1680
        }
1681
 
1682
        /* If the ->len variable is non-zero the connection has
1683
           already data in transit and cannot send anymore right
1684
           now. */
1685
        if(uip_connr->len == 0) {
1686
 
1687
          /* The application cannot send more than what is allowed by
1688
             the mss (the minumum of the MSS and the available
1689
             window). */
1690
          if(uip_slen > uip_connr->mss) {
1691
            uip_slen = uip_connr->mss;
1692
          }
1693
 
1694
          /* Remember how much data we send out now so that we know
1695
             when everything has been acknowledged. */
1696
          uip_connr->len = uip_slen;
1697
        } else {
1698
 
1699
          /* If the application already had unacknowledged data, we
1700
             make sure that the application does not send (i.e.,
1701
             retransmit) out more than it previously sent out. */
1702
          uip_slen = uip_connr->len;
1703
        }
1704
      }
1705
      uip_connr->nrtx = 0;
1706
    apprexmit:
1707
      uip_appdata = uip_sappdata;
1708
 
1709
      /* If the application has data to be sent, or if the incoming
1710
         packet had new data in it, we must send out a packet. */
1711
      if(uip_slen > 0 && uip_connr->len > 0) {
1712
        /* Add the length of the IP and TCP headers. */
1713
        uip_len = uip_connr->len + UIP_TCPIP_HLEN;
1714
        /* We always set the ACK flag in response packets. */
1715
        BUF->flags = TCP_ACK | TCP_PSH;
1716
        /* Send the packet. */
1717
        goto tcp_send_noopts;
1718
      }
1719
      /* If there is no data to send, just send out a pure ACK if
1720
         there is newdata. */
1721
      if(uip_flags & UIP_NEWDATA) {
1722
        uip_len = UIP_TCPIP_HLEN;
1723
        BUF->flags = TCP_ACK;
1724
        goto tcp_send_noopts;
1725
      }
1726
    }
1727
    goto drop;
1728
  case UIP_LAST_ACK:
1729
    /* We can close this connection if the peer has acknowledged our
1730
       FIN. This is indicated by the UIP_ACKDATA flag. */
1731
    if(uip_flags & UIP_ACKDATA) {
1732
      uip_connr->tcpstateflags = UIP_CLOSED;
1733
      uip_flags = UIP_CLOSE;
1734
      UIP_APPCALL();
1735
    }
1736
    break;
1737
 
1738
  case UIP_FIN_WAIT_1:
1739
    /* The application has closed the connection, but the remote host
1740
       hasn't closed its end yet. Thus we do nothing but wait for a
1741
       FIN from the other side. */
1742
    if(uip_len > 0) {
1743
      uip_add_rcv_nxt(uip_len);
1744
    }
1745
    if(BUF->flags & TCP_FIN) {
1746
      if(uip_flags & UIP_ACKDATA) {
1747
        uip_connr->tcpstateflags = UIP_TIME_WAIT;
1748
        uip_connr->timer = 0;
1749
        uip_connr->len = 0;
1750
      } else {
1751
        uip_connr->tcpstateflags = UIP_CLOSING;
1752
      }
1753
      uip_add_rcv_nxt(1);
1754
      uip_flags = UIP_CLOSE;
1755
      UIP_APPCALL();
1756
      goto tcp_send_ack;
1757
    } else if(uip_flags & UIP_ACKDATA) {
1758
      uip_connr->tcpstateflags = UIP_FIN_WAIT_2;
1759
      uip_connr->len = 0;
1760
      goto drop;
1761
    }
1762
    if(uip_len > 0) {
1763
      goto tcp_send_ack;
1764
    }
1765
    goto drop;
1766
 
1767
  case UIP_FIN_WAIT_2:
1768
    if(uip_len > 0) {
1769
      uip_add_rcv_nxt(uip_len);
1770
    }
1771
    if(BUF->flags & TCP_FIN) {
1772
      uip_connr->tcpstateflags = UIP_TIME_WAIT;
1773
      uip_connr->timer = 0;
1774
      uip_add_rcv_nxt(1);
1775
      uip_flags = UIP_CLOSE;
1776
      UIP_APPCALL();
1777
      goto tcp_send_ack;
1778
    }
1779
    if(uip_len > 0) {
1780
      goto tcp_send_ack;
1781
    }
1782
    goto drop;
1783
 
1784
  case UIP_TIME_WAIT:
1785
    goto tcp_send_ack;
1786
 
1787
  case UIP_CLOSING:
1788
    if(uip_flags & UIP_ACKDATA) {
1789
      uip_connr->tcpstateflags = UIP_TIME_WAIT;
1790
      uip_connr->timer = 0;
1791
    }
1792
  }
1793
  goto drop;
1794
 
1795
 
1796
  /* We jump here when we are ready to send the packet, and just want
1797
     to set the appropriate TCP sequence numbers in the TCP header. */
1798
 tcp_send_ack:
1799
  BUF->flags = TCP_ACK;
1800
 tcp_send_nodata:
1801
  uip_len = UIP_IPTCPH_LEN;
1802
 tcp_send_noopts:
1803
  BUF->tcpoffset = (UIP_TCPH_LEN / 4) << 4;
1804
 tcp_send:
1805
  /* We're done with the input processing. We are now ready to send a
1806
     reply. Our job is to fill in all the fields of the TCP and IP
1807
     headers before calculating the checksum and finally send the
1808
     packet. */
1809
  BUF->ackno[0] = uip_connr->rcv_nxt[0];
1810
  BUF->ackno[1] = uip_connr->rcv_nxt[1];
1811
  BUF->ackno[2] = uip_connr->rcv_nxt[2];
1812
  BUF->ackno[3] = uip_connr->rcv_nxt[3];
1813
 
1814
  BUF->seqno[0] = uip_connr->snd_nxt[0];
1815
  BUF->seqno[1] = uip_connr->snd_nxt[1];
1816
  BUF->seqno[2] = uip_connr->snd_nxt[2];
1817
  BUF->seqno[3] = uip_connr->snd_nxt[3];
1818
 
1819
  BUF->proto = UIP_PROTO_TCP;
1820
 
1821
  BUF->srcport  = uip_connr->lport;
1822
  BUF->destport = uip_connr->rport;
1823
 
1824
  uip_ipaddr_copy(BUF->srcipaddr, uip_hostaddr);
1825
  uip_ipaddr_copy(BUF->destipaddr, uip_connr->ripaddr);
1826
 
1827
  if(uip_connr->tcpstateflags & UIP_STOPPED) {
1828
    /* If the connection has issued uip_stop(), we advertise a zero
1829
       window so that the remote host will stop sending data. */
1830
    BUF->wnd[0] = BUF->wnd[1] = 0;
1831
  } else {
1832
    BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8);
1833
    BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff);
1834
  }
1835
 
1836
 tcp_send_noconn:
1837
  BUF->ttl = UIP_TTL;
1838
#if UIP_CONF_IPV6
1839
  /* For IPv6, the IP length field does not include the IPv6 IP header
1840
     length. */
1841
  BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
1842
  BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
1843
#else /* UIP_CONF_IPV6 */
1844
  BUF->len[0] = (uip_len >> 8);
1845
  BUF->len[1] = (uip_len & 0xff);
1846
#endif /* UIP_CONF_IPV6 */
1847
 
1848
  BUF->urgp[0] = BUF->urgp[1] = 0;
1849
 
1850
  /* Calculate TCP checksum. */
1851
  BUF->tcpchksum = 0;
1852
  BUF->tcpchksum = ~(uip_tcpchksum());
1853
 
1854
#if UIP_UDP
1855
 ip_send_nolen:
1856
#endif /* UIP_UDP */
1857
 
1858
#if UIP_CONF_IPV6
1859
  BUF->vtc = 0x60;
1860
  BUF->tcflow = 0x00;
1861
  BUF->flow = 0x00;
1862
#else /* UIP_CONF_IPV6 */
1863
  BUF->vhl = 0x45;
1864
  BUF->tos = 0;
1865
  BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
1866
  ++ipid;
1867
  BUF->ipid[0] = ipid >> 8;
1868
  BUF->ipid[1] = ipid & 0xff;
1869
  /* Calculate IP checksum. */
1870
  BUF->ipchksum = 0;
1871
  BUF->ipchksum = ~(uip_ipchksum());
1872
  DEBUG_PRINTF("uip ip_send_nolen: chkecum 0x%04x\n", uip_ipchksum());
1873
#endif /* UIP_CONF_IPV6 */
1874
 
1875
  UIP_STAT(++uip_stat.tcp.sent);
1876
 send:
1877
  DEBUG_PRINTF("Sending packet with length %d (%d)\n", uip_len,
1878
               (BUF->len[0] << 8) | BUF->len[1]);
1879
 
1880
  UIP_STAT(++uip_stat.ip.sent);
1881
  /* Return and let the caller do the actual transmission. */
1882
  uip_flags = 0;
1883
  return;
1884
 drop:
1885
  uip_len = 0;
1886
  uip_flags = 0;
1887
  return;
1888
}
1889
/*---------------------------------------------------------------------------*/
1890
u16_t
1891
htons(u16_t val)
1892
{
1893
  return HTONS(val);
1894
}
1895
/*---------------------------------------------------------------------------*/
1896
void
1897
uip_send(const void *data, int len)
1898
{
1899
  if(len > 0) {
1900
    uip_slen = len;
1901
    if(data != uip_sappdata) {
1902
      memcpy(uip_sappdata, (data), uip_slen);
1903
    }
1904
  }
1905
}
1906
/** @} */

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