1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
|
/****************************************************************************
* uip_tcpconn.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Large parts of this file were leveraged from uIP logic:
*
* Copyright (c) 2001-2003, Adam Dunkels.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Compilation Switches
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP)
#include <sys/types.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include <net/uip/uipopt.h>
#include <net/uip/uip.h>
#include <net/uip/uip-arch.h>
#include "uip-internal.h"
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/* The array containing all uIP TCP connections. */
static struct uip_conn g_tcp_connections[CONFIG_NET_TCP_CONNS];
/* A list of all free TCP connections */
static dq_queue_t g_free_tcp_connections;
/* A list of all connected TCP connections */
static dq_queue_t g_active_tcp_connections;
/* Last port used by a TCP connection connection. */
static uint16 g_last_tcp_port;
/* g_tcp_sequence[] is used to generate TCP sequence numbers */
static uint8 g_tcp_sequence[4];
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: uip_selectport()
*
* Description:
* If the portnumber is zero; select an unused port for the connection.
* If the portnumber is non-zero, verify that no other connection has
* been created with this port number.
*
* Input Parameters:
* portno -- the selected port number in host order. Zero means no port
* selected.
*
* Return:
* 0 on success, negated errno on failure:
*
* EADDRINUSE
* The given address is already in use.
* EADDRNOTAVAIL
* Cannot assign requested address (unlikely)
*
* Assumptions:
* Interrupts are disabled
*
****************************************************************************/
static int uip_selectport(uint16 portno)
{
if (portno == 0)
{
/* No local port assigned. Loop until we find a valid listen port number
* that is not being used by any other connection. NOTE the following loop
* is assumed to terminate but could not if all 32000-4096+1 ports are
* in used (unlikely).
*/
do
{
/* Guess that the next available port number will be the one after
* the last port number assigned.
*/
portno = ++g_last_tcp_port;
/* Make sure that the port number is within range */
if (g_last_tcp_port >= 32000)
{
g_last_tcp_port = 4096;
}
}
while (uip_tcplistener(htons(g_last_tcp_port)));
}
else
{
/* A port number has been supplied. Verify that no other TCP/IP
* connection is using this local port.
*/
if (uip_tcplistener(portno))
{
/* It is in use... return EADDRINUSE */
return -EADDRINUSE;
}
}
/* Return the selected or verified port number */
return portno;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: uip_tcpinit()
*
* Description:
* Initialize the TCP/IP connection structures. Called only once and only
* from the UIP layer at startup in normal user mode.
*
****************************************************************************/
void uip_tcpinit(void)
{
int i;
/* Initialize the queues */
dq_init(&g_free_tcp_connections);
dq_init(&g_active_tcp_connections);
/* Now initialize each connection structure */
for (i = 0; i < CONFIG_NET_TCP_CONNS; i++)
{
/* Mark the connection closed and move it to the free list */
g_tcp_connections[i].tcpstateflags = UIP_CLOSED;
dq_addlast(&g_tcp_connections[i].node, &g_free_tcp_connections);
}
g_last_tcp_port = 1024;
}
/****************************************************************************
* Name: uip_tcpalloc()
*
* Description:
* Find a free TCP/IP connection structure and allocate it
* for use. This is normally something done by the implementation of the
* socket() API but is also called from the interrupt level when a TCP
* packet is received while "listening"
*
****************************************************************************/
struct uip_conn *uip_tcpalloc(void)
{
struct uip_conn *conn;
irqstate_t flags;
/* Because this routine is called from both interrupt level and
* and from user level, we have not option but to disable interrupts
* while accessing g_free_tcp_connections[];
*/
flags = irqsave();
/* Return the entry from the head of the free list */
conn = (struct uip_conn *)dq_remfirst(&g_free_tcp_connections);
#if 0 /* Revisit */
/* Is the free list empty? */
if (!conn)
{
/* As a fallback, check for connection structures in the TIME_WAIT
* state. If no CLOSED connections are found, then take the oldest
*/
struct uip_conn *tmp = g_active_tcp_connections.head;
while (tmp)
{
/* Is this connectin in the UIP_TIME_WAIT state? */
if (tmp->tcpstateflags == UIP_TIME_WAIT)
{
/* Is it the oldest one we have seen so far? */
if (!conn || tmp->timer > conn->timer)
{
/* Yes.. remember it */
conn = tmp;
}
}
/* Look at the next active connection */
tmp = tmp->node.flink;
}
/* If we found one, remove it from the active connection list */
dq_rem(&conn->node, &g_active_tcp_connections);
}
#endif
irqrestore(flags);
/* Mark the connection allocated */
if (conn)
{
conn->tcpstateflags = UIP_ALLOCATED;
}
return conn;
}
/****************************************************************************
* Name: uip_tcpfree()
*
* Description:
* Free a connection structure that is no longer in use. This should be
* done by the implementation of close()
*
****************************************************************************/
void uip_tcpfree(struct uip_conn *conn)
{
#if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0
struct uip_readahead_s *readahead;
#endif
irqstate_t flags;
/* Because g_free_tcp_connections is accessed from user level and interrupt
* level, code, it is necessary to keep interrupts disabled during this
* operation.
*/
flags = irqsave();
/* UIP_ALLOCATED means that that the connection is not in the active list
* yet.
*/
if (conn->tcpstateflags != UIP_ALLOCATED)
{
/* Remove the connection from the active list */
dq_rem(&conn->node, &g_active_tcp_connections);
}
/* Release any read-ahead buffers attached to the connection */
#if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0
while ((readahead = (struct uip_readahead_s *)sq_remfirst(&conn->readahead)) != NULL)
{
uip_tcpreadaheadrelease(readahead);
}
#endif
/* Remove any backlog attached to this connection */
#ifdef CONFIG_NET_TCPBACKLOG
if (conn->backlog)
{
uip_backlogdestroy(conn);
}
/* If this connection is, itself, backlogged, then remove it from the
* parent connection's backlog list.
*/
if (conn->blparent)
{
uip_backlogdelete(conn->blparent, conn);
}
#endif
/* Mark the connection available and put it into the free list */
conn->tcpstateflags = UIP_CLOSED;
dq_addlast(&conn->node, &g_free_tcp_connections);
irqrestore(flags);
}
/****************************************************************************
* Name: uip_tcpactive()
*
* Description:
* Find a connection structure that is the appropriate
* connection to be used withi the provided TCP/IP header
*
* Assumptions:
* This function is called from UIP logic at interrupt level
*
****************************************************************************/
struct uip_conn *uip_tcpactive(struct uip_tcpip_hdr *buf)
{
struct uip_conn *conn = (struct uip_conn *)g_active_tcp_connections.head;
in_addr_t srcipaddr = uip_ip4addr_conv(buf->srcipaddr);
while (conn)
{
/* Find an open connection matching the tcp input */
if (conn->tcpstateflags != UIP_CLOSED &&
buf->destport == conn->lport && buf->srcport == conn->rport &&
uip_ipaddr_cmp(srcipaddr, conn->ripaddr))
{
/* Matching connection found.. break out of the loop and return a
* reference to it.
*/
break;
}
/* Look at the next active connection */
conn = (struct uip_conn *)conn->node.flink;
}
return conn;
}
/****************************************************************************
* Name: uip_nexttcpconn()
*
* Description:
* Traverse the list of active TCP connections
*
* Assumptions:
* This function is called from UIP logic at interrupt level (or with
* interrupts disabled).
*
****************************************************************************/
struct uip_conn *uip_nexttcpconn(struct uip_conn *conn)
{
if (!conn)
{
return (struct uip_conn *)g_active_tcp_connections.head;
}
else
{
return (struct uip_conn *)conn->node.flink;
}
}
/****************************************************************************
* Name: uip_tcplistener()
*
* Description:
* Given a local port number (in network byte order), find the TCP
* connection that listens on this this port.
*
* Primary uses: (1) to determine if a port number is available, (2) to
* To idenfity the socket that will accept new connections on a local port.
*
****************************************************************************/
struct uip_conn *uip_tcplistener(uint16 portno)
{
struct uip_conn *conn;
int i;
/* Check if this port number is in use by any active UIP TCP connection */
for (i = 0; i < CONFIG_NET_TCP_CONNS; i++)
{
conn = &g_tcp_connections[i];
if (conn->tcpstateflags != UIP_CLOSED && conn->lport == portno)
{
/* The portnumber is in use, return the connection */
return conn;
}
}
return NULL;
}
/****************************************************************************
* Name: uip_tcpaccept()
*
* Description:
* Called when uip_interupt matches the incoming packet with a connection
* in LISTEN. In that case, this function will create a new connection and
* initialize it to send a SYNACK in return.
*
* Assumptions:
* This function is called from UIP logic at interrupt level
*
****************************************************************************/
struct uip_conn *uip_tcpaccept(struct uip_tcpip_hdr *buf)
{
struct uip_conn *conn = uip_tcpalloc();
if (conn)
{
/* Fill in the necessary fields for the new connection. */
conn->rto = UIP_RTO;
conn->timer = UIP_RTO;
conn->sa = 0;
conn->sv = 4;
conn->nrtx = 0;
conn->lport = buf->destport;
conn->rport = buf->srcport;
uip_ipaddr_copy(conn->ripaddr, uip_ip4addr_conv(buf->srcipaddr));
conn->tcpstateflags = UIP_SYN_RCVD;
memcpy(conn->snd_nxt, g_tcp_sequence, 4);
conn->len = 1;
/* rcv_nxt should be the seqno from the incoming packet + 1. */
memcpy(conn->rcv_nxt, buf->seqno, 4);
/* Initialize the list of TCP read-ahead buffers */
#if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0
sq_init(&conn->readahead);
#endif
/* And, finally, put the connection structure into the active list.
* Interrupts should already be disabled in this context.
*/
dq_addlast(&conn->node, &g_active_tcp_connections);
}
return conn;
}
/****************************************************************************
* Name: uip_tcpnextsequence()
*
* Description:
* Increment the TCP/IP sequence number
*
* Assumptions:
* This function is called from the interrupt level
*
****************************************************************************/
void uip_tcpnextsequence(void)
{
/* This inplements a byte-by-byte big-endian increment */
if (++g_tcp_sequence[3] == 0)
{
if (++g_tcp_sequence[2] == 0)
{
if (++g_tcp_sequence[1] == 0)
{
++g_tcp_sequence[0];
}
}
}
}
/****************************************************************************
* Name: uip_tcpbind()
*
* Description:
* This function implements the UIP specific parts of the standard TCP
* bind() operation.
*
* Return:
* 0 on success or -EADDRINUSE on failure
*
* Assumptions:
* This function is called from normal user level code.
*
****************************************************************************/
#ifdef CONFIG_NET_IPv6
int uip_tcpbind(struct uip_conn *conn, const struct sockaddr_in6 *addr)
#else
int uip_tcpbind(struct uip_conn *conn, const struct sockaddr_in *addr)
#endif
{
irqstate_t flags;
int port;
/* Verify or select a local port */
flags = irqsave();
port = uip_selectport(ntohs(addr->sin_port));
irqrestore(flags);
if (port < 0)
{
return port;
}
/* Save the local address in the connection structure. Note that the requested
* local IP address is saved but not used. At present, only a single network
* interface is supported, the IP address is not of importance.
*/
conn->lport = addr->sin_port;
#if 0 /* Not used */
#ifdef CONFIG_NET_IPv6
uip_ipaddr_copy(conn->lipaddr, addr->sin6_addr.in6_u.u6_addr16);
#else
uip_ipaddr_copy(conn->lipaddr, addr->sin_addr.s_addr);
#endif
#endif
return OK;
}
/****************************************************************************
* Name: uip_tcpconnect()
*
* Description:
* This function implements the UIP specific parts of the standard
* TCP connect() operation: It connects to a remote host using TCP.
*
* This function is used to start a new connection to the specified
* port on the specied host. It uses the connection structure that was
* allocated by a preceding socket() call. It sets the connection to
* the SYN_SENT state and sets the retransmission timer to 0. This will
* cause a TCP SYN segment to be sent out the next time this connection
* is periodically processed, which usually is done within 0.5 seconds
* after the call to uip_tcpconnect().
*
* Assumptions:
* This function is called from normal user level code.
*
****************************************************************************/
#ifdef CONFIG_NET_IPv6
int uip_tcpconnect(struct uip_conn *conn, const struct sockaddr_in6 *addr)
#else
int uip_tcpconnect(struct uip_conn *conn, const struct sockaddr_in *addr)
#endif
{
irqstate_t flags;
int port;
/* The connection is expected to be in the UIP_ALLOCATED state.. i.e.,
* allocated via up_tcpalloc(), but not yet put into the active connections
* list.
*/
if (!conn || conn->tcpstateflags != UIP_ALLOCATED)
{
return -EISCONN;
}
/* If the TCP port has not alread been bound to a local port, then select
* one now.
*/
flags = irqsave();
port = uip_selectport(ntohs(conn->lport));
irqrestore(flags);
if (port < 0)
{
return port;
}
/* Initialize and return the connection structure, bind it to the port number */
conn->tcpstateflags = UIP_SYN_SENT;
memcpy(conn->snd_nxt, g_tcp_sequence, 4);
conn->initialmss = conn->mss = UIP_TCP_MSS;
conn->len = 1; /* TCP length of the SYN is one. */
conn->nrtx = 0;
conn->timer = 1; /* Send the SYN next time around. */
conn->rto = UIP_RTO;
conn->sa = 0;
conn->sv = 16; /* Initial value of the RTT variance. */
conn->lport = htons((uint16)port);
/* The sockaddr port is 16 bits and already in network order */
conn->rport = addr->sin_port;
/* The sockaddr address is 32-bits in network order. */
uip_ipaddr_copy(conn->ripaddr, addr->sin_addr.s_addr);
/* Initialize the list of TCP read-ahead buffers */
#if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0
sq_init(&conn->readahead);
#endif
/* And, finally, put the connection structure into the active
* list. Because g_active_tcp_connections is accessed from user level and
* interrupt level, code, it is necessary to keep interrupts disabled during
* this operation.
*/
flags = irqsave();
dq_addlast(&conn->node, &g_active_tcp_connections);
irqrestore(flags);
return OK;
}
#endif /* CONFIG_NET && CONFIG_NET_TCP */
|