1 /**
2 * @file
3 * SLIP Interface
4 *
5 */
6
7 /*
8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * This file is built upon the file: src/arch/rtxc/netif/sioslip.c
36 *
37 * Author: Magnus Ivarsson <magnus.ivarsson(at)volvo.com>
38 * Simon Goldschmidt
39 */
40
41
42 /**
43 * @defgroup slipif SLIP
44 * @ingroup netifs
45 *
46 * This is an arch independent SLIP netif. The specific serial hooks must be
47 * provided by another file. They are sio_open, sio_read/sio_tryread and sio_send
48 *
49 * Usage: This netif can be used in three ways:
50 * 1. For NO_SYS==0, an RX thread can be used which blocks on sio_read()
51 * until data is received.
52 * 2. In your main loop, call slipif_poll() to check for new RX bytes,
53 * completed packets are fed into netif->input().
54 * 3. Call slipif_received_byte[s]() from your serial RX ISR and
55 * slipif_process_rxqueue() from your main loop. ISR level decodes
56 * packets and puts completed packets on a queue which is fed into
57 * the stack from the main loop (needs SYS_LIGHTWEIGHT_PROT for
58 * pbuf_alloc to work on ISR level!).
59 *
60 */
61
62 #include "netif/slipif.h"
63 #include "lwip/opt.h"
64
65 #include "lwip/def.h"
66 #include "lwip/pbuf.h"
67 #include "lwip/stats.h"
68 #include "lwip/snmp.h"
69 #include "lwip/sys.h"
70 #include "lwip/sio.h"
71
72 #define SLIP_END 0xC0 /* 0300: start and end of every packet */
73 #define SLIP_ESC 0xDB /* 0333: escape start (one byte escaped data follows) */
74 #define SLIP_ESC_END 0xDC /* 0334: following escape: original byte is 0xC0 (END) */
75 #define SLIP_ESC_ESC 0xDD /* 0335: following escape: original byte is 0xDB (ESC) */
76
77 /** Maximum packet size that is received by this netif */
78 #ifndef SLIP_MAX_SIZE
79 #define SLIP_MAX_SIZE 1500
80 #endif
81
82 /** Define this to the interface speed for SNMP
83 * (sio_fd is the sio_fd_t returned by sio_open).
84 * The default value of zero means 'unknown'.
85 */
86 #ifndef SLIP_SIO_SPEED
87 #define SLIP_SIO_SPEED(sio_fd) 0
88 #endif
89
90 enum slipif_recv_state {
91 SLIP_RECV_NORMAL,
92 SLIP_RECV_ESCAPE
93 };
94
95 struct slipif_priv {
96 sio_fd_t sd;
97 /* q is the whole pbuf chain for a packet, p is the current pbuf in the chain */
98 struct pbuf *p, *q;
99 u8_t state;
100 u16_t i, recved;
101 #if SLIP_RX_FROM_ISR
102 struct pbuf *rxpackets;
103 #endif
104 };
105
106 /**
107 * Send a pbuf doing the necessary SLIP encapsulation
108 *
109 * Uses the serial layer's sio_send()
110 *
111 * @param netif the lwip network interface structure for this slipif
112 * @param p the pbuf chain packet to send
113 * @return always returns ERR_OK since the serial layer does not provide return values
114 */
115 static err_t
slipif_output(struct netif * netif,struct pbuf * p)116 slipif_output(struct netif *netif, struct pbuf *p)
117 {
118 struct slipif_priv *priv;
119 struct pbuf *q;
120 u16_t i;
121 u8_t c;
122
123 LWIP_ASSERT("netif != NULL", (netif != NULL));
124 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
125 LWIP_ASSERT("p != NULL", (p != NULL));
126
127 LWIP_DEBUGF(SLIP_DEBUG, ("slipif_output: sending %"U16_F" bytes\n", p->tot_len));
128 priv = (struct slipif_priv *)netif->state;
129
130 /* Send pbuf out on the serial I/O device. */
131 /* Start with packet delimiter. */
132 sio_send(SLIP_END, priv->sd);
133
134 for (q = p; q != NULL; q = q->next) {
135 for (i = 0; i < q->len; i++) {
136 c = ((u8_t *)q->payload)[i];
137 switch (c) {
138 case SLIP_END:
139 /* need to escape this byte (0xC0 -> 0xDB, 0xDC) */
140 sio_send(SLIP_ESC, priv->sd);
141 sio_send(SLIP_ESC_END, priv->sd);
142 break;
143 case SLIP_ESC:
144 /* need to escape this byte (0xDB -> 0xDB, 0xDD) */
145 sio_send(SLIP_ESC, priv->sd);
146 sio_send(SLIP_ESC_ESC, priv->sd);
147 break;
148 default:
149 /* normal byte - no need for escaping */
150 sio_send(c, priv->sd);
151 break;
152 }
153 }
154 }
155 /* End with packet delimiter. */
156 sio_send(SLIP_END, priv->sd);
157 return ERR_OK;
158 }
159
160 #if LWIP_IPV4
161 /**
162 * Send a pbuf doing the necessary SLIP encapsulation
163 *
164 * Uses the serial layer's sio_send()
165 *
166 * @param netif the lwip network interface structure for this slipif
167 * @param p the pbuf chain packet to send
168 * @param ipaddr the ip address to send the packet to (not used for slipif)
169 * @return always returns ERR_OK since the serial layer does not provide return values
170 */
171 static err_t
slipif_output_v4(struct netif * netif,struct pbuf * p,const ip4_addr_t * ipaddr)172 slipif_output_v4(struct netif *netif, struct pbuf *p, const ip4_addr_t *ipaddr)
173 {
174 LWIP_UNUSED_ARG(ipaddr);
175 return slipif_output(netif, p);
176 }
177 #endif /* LWIP_IPV4 */
178
179 #if LWIP_IPV6
180 /**
181 * Send a pbuf doing the necessary SLIP encapsulation
182 *
183 * Uses the serial layer's sio_send()
184 *
185 * @param netif the lwip network interface structure for this slipif
186 * @param p the pbuf chain packet to send
187 * @param ipaddr the ip address to send the packet to (not used for slipif)
188 * @return always returns ERR_OK since the serial layer does not provide return values
189 */
190 static err_t
slipif_output_v6(struct netif * netif,struct pbuf * p,const ip6_addr_t * ipaddr)191 slipif_output_v6(struct netif *netif, struct pbuf *p, const ip6_addr_t *ipaddr)
192 {
193 LWIP_UNUSED_ARG(ipaddr);
194 return slipif_output(netif, p);
195 }
196 #endif /* LWIP_IPV6 */
197
198 /**
199 * Handle the incoming SLIP stream character by character
200 *
201 * @param netif the lwip network interface structure for this slipif
202 * @param c received character (multiple calls to this function will
203 * return a complete packet, NULL is returned before - used for polling)
204 * @return The IP packet when SLIP_END is received
205 */
206 static struct pbuf *
slipif_rxbyte(struct netif * netif,u8_t c)207 slipif_rxbyte(struct netif *netif, u8_t c)
208 {
209 struct slipif_priv *priv;
210 struct pbuf *t;
211
212 LWIP_ASSERT("netif != NULL", (netif != NULL));
213 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
214
215 priv = (struct slipif_priv *)netif->state;
216
217 switch (priv->state) {
218 case SLIP_RECV_NORMAL:
219 switch (c) {
220 case SLIP_END:
221 if (priv->recved > 0) {
222 /* Received whole packet. */
223 /* Trim the pbuf to the size of the received packet. */
224 pbuf_realloc(priv->q, priv->recved);
225
226 LINK_STATS_INC(link.recv);
227
228 LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet (%"U16_F" bytes)\n", priv->recved));
229 t = priv->q;
230 priv->p = priv->q = NULL;
231 priv->i = priv->recved = 0;
232 return t;
233 }
234 return NULL;
235 case SLIP_ESC:
236 priv->state = SLIP_RECV_ESCAPE;
237 return NULL;
238 default:
239 break;
240 } /* end switch (c) */
241 break;
242 case SLIP_RECV_ESCAPE:
243 /* un-escape END or ESC bytes, leave other bytes
244 (although that would be a protocol error) */
245 switch (c) {
246 case SLIP_ESC_END:
247 c = SLIP_END;
248 break;
249 case SLIP_ESC_ESC:
250 c = SLIP_ESC;
251 break;
252 default:
253 break;
254 }
255 priv->state = SLIP_RECV_NORMAL;
256 break;
257 default:
258 break;
259 } /* end switch (priv->state) */
260
261 /* byte received, packet not yet completely received */
262 if (priv->p == NULL) {
263 /* allocate a new pbuf */
264 LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
265 priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN - PBUF_LINK_ENCAPSULATION_HLEN), PBUF_POOL);
266
267 if (priv->p == NULL) {
268 LINK_STATS_INC(link.drop);
269 LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
270 /* don't process any further since we got no pbuf to receive to */
271 return NULL;
272 }
273
274 if (priv->q != NULL) {
275 /* 'chain' the pbuf to the existing chain */
276 pbuf_cat(priv->q, priv->p);
277 } else {
278 /* p is the first pbuf in the chain */
279 priv->q = priv->p;
280 }
281 }
282
283 /* this automatically drops bytes if > SLIP_MAX_SIZE */
284 if ((priv->p != NULL) && (priv->recved <= SLIP_MAX_SIZE)) {
285 ((u8_t *)priv->p->payload)[priv->i] = c;
286 priv->recved++;
287 priv->i++;
288 if (priv->i >= priv->p->len) {
289 /* on to the next pbuf */
290 priv->i = 0;
291 if (priv->p->next != NULL && priv->p->next->len > 0) {
292 /* p is a chain, on to the next in the chain */
293 priv->p = priv->p->next;
294 } else {
295 /* p is a single pbuf, set it to NULL so next time a new
296 * pbuf is allocated */
297 priv->p = NULL;
298 }
299 }
300 }
301 return NULL;
302 }
303
304 /** Like slipif_rxbyte, but passes completed packets to netif->input
305 *
306 * @param netif The lwip network interface structure for this slipif
307 * @param c received character
308 */
309 static void
slipif_rxbyte_input(struct netif * netif,u8_t c)310 slipif_rxbyte_input(struct netif *netif, u8_t c)
311 {
312 struct pbuf *p;
313 p = slipif_rxbyte(netif, c);
314 if (p != NULL) {
315 if (netif->input(p, netif) != ERR_OK) {
316 pbuf_free(p);
317 }
318 }
319 }
320
321 #if SLIP_USE_RX_THREAD
322 /**
323 * The SLIP input thread.
324 *
325 * Feed the IP layer with incoming packets
326 *
327 * @param nf the lwip network interface structure for this slipif
328 */
329 static void
slipif_loop_thread(void * nf)330 slipif_loop_thread(void *nf)
331 {
332 u8_t c;
333 struct netif *netif = (struct netif *)nf;
334 struct slipif_priv *priv = (struct slipif_priv *)netif->state;
335
336 while (1) {
337 if (sio_read(priv->sd, &c, 1) > 0) {
338 slipif_rxbyte_input(netif, c);
339 }
340 }
341 }
342 #endif /* SLIP_USE_RX_THREAD */
343
344 /**
345 * @ingroup slipif
346 * SLIP netif initialization
347 *
348 * Call the arch specific sio_open and remember
349 * the opened device in the state field of the netif.
350 *
351 * @param netif the lwip network interface structure for this slipif
352 * @return ERR_OK if serial line could be opened,
353 * ERR_MEM if no memory could be allocated,
354 * ERR_IF is serial line couldn't be opened
355 *
356 * @note If netif->state is interpreted as an u8_t serial port number.
357 *
358 */
359 err_t
slipif_init(struct netif * netif)360 slipif_init(struct netif *netif)
361 {
362 struct slipif_priv *priv;
363 u8_t sio_num;
364
365 LWIP_ASSERT("slipif needs an input callback", netif->input != NULL);
366
367 /* netif->state contains serial port number */
368 sio_num = LWIP_PTR_NUMERIC_CAST(u8_t, netif->state);
369
370 LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)sio_num));
371
372 /* Allocate private data */
373 priv = (struct slipif_priv *)mem_malloc(sizeof(struct slipif_priv));
374 if (!priv) {
375 return ERR_MEM;
376 }
377
378 netif->name[0] = 's';
379 netif->name[1] = 'l';
380 #if LWIP_IPV4
381 netif->output = slipif_output_v4;
382 #endif /* LWIP_IPV4 */
383 #if LWIP_IPV6
384 netif->output_ip6 = slipif_output_v6;
385 #endif /* LWIP_IPV6 */
386 netif->mtu = SLIP_MAX_SIZE;
387
388 /* Try to open the serial port. */
389 priv->sd = sio_open(sio_num);
390 if (!priv->sd) {
391 /* Opening the serial port failed. */
392 mem_free(priv);
393 return ERR_IF;
394 }
395
396 /* Initialize private data */
397 priv->p = NULL;
398 priv->q = NULL;
399 priv->state = SLIP_RECV_NORMAL;
400 priv->i = 0;
401 priv->recved = 0;
402 #if SLIP_RX_FROM_ISR
403 priv->rxpackets = NULL;
404 #endif
405
406 netif->state = priv;
407
408 /* initialize the snmp variables and counters inside the struct netif */
409 MIB2_INIT_NETIF(netif, snmp_ifType_slip, SLIP_SIO_SPEED(priv->sd));
410
411 #if SLIP_USE_RX_THREAD
412 /* Create a thread to poll the serial line. */
413 sys_thread_new(SLIPIF_THREAD_NAME, slipif_loop_thread, netif,
414 SLIPIF_THREAD_STACKSIZE, SLIPIF_THREAD_PRIO);
415 #endif /* SLIP_USE_RX_THREAD */
416 return ERR_OK;
417 }
418
419 /**
420 * @ingroup slipif
421 * Polls the serial device and feeds the IP layer with incoming packets.
422 *
423 * @param netif The lwip network interface structure for this slipif
424 */
425 void
slipif_poll(struct netif * netif)426 slipif_poll(struct netif *netif)
427 {
428 u8_t c;
429 struct slipif_priv *priv;
430
431 LWIP_ASSERT("netif != NULL", (netif != NULL));
432 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
433
434 priv = (struct slipif_priv *)netif->state;
435
436 while (sio_tryread(priv->sd, &c, 1) > 0) {
437 slipif_rxbyte_input(netif, c);
438 }
439 }
440
441 #if SLIP_RX_FROM_ISR
442 /**
443 * @ingroup slipif
444 * Feeds the IP layer with incoming packets that were receive
445 *
446 * @param netif The lwip network interface structure for this slipif
447 */
448 void
slipif_process_rxqueue(struct netif * netif)449 slipif_process_rxqueue(struct netif *netif)
450 {
451 struct slipif_priv *priv;
452 SYS_ARCH_DECL_PROTECT(old_level);
453
454 LWIP_ASSERT("netif != NULL", (netif != NULL));
455 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
456
457 priv = (struct slipif_priv *)netif->state;
458
459 SYS_ARCH_PROTECT(old_level);
460 while (priv->rxpackets != NULL) {
461 struct pbuf *p = priv->rxpackets;
462 #if SLIP_RX_QUEUE
463 /* dequeue packet */
464 struct pbuf *q = p;
465 while ((q->len != q->tot_len) && (q->next != NULL)) {
466 q = q->next;
467 }
468 priv->rxpackets = q->next;
469 q->next = NULL;
470 #else /* SLIP_RX_QUEUE */
471 priv->rxpackets = NULL;
472 #endif /* SLIP_RX_QUEUE */
473 SYS_ARCH_UNPROTECT(old_level);
474 if (netif->input(p, netif) != ERR_OK) {
475 pbuf_free(p);
476 }
477 SYS_ARCH_PROTECT(old_level);
478 }
479 SYS_ARCH_UNPROTECT(old_level);
480 }
481
482 /** Like slipif_rxbyte, but queues completed packets.
483 *
484 * @param netif The lwip network interface structure for this slipif
485 * @param data Received serial byte
486 */
487 static void
slipif_rxbyte_enqueue(struct netif * netif,u8_t data)488 slipif_rxbyte_enqueue(struct netif *netif, u8_t data)
489 {
490 struct pbuf *p;
491 struct slipif_priv *priv = (struct slipif_priv *)netif->state;
492 SYS_ARCH_DECL_PROTECT(old_level);
493
494 p = slipif_rxbyte(netif, data);
495 if (p != NULL) {
496 SYS_ARCH_PROTECT(old_level);
497 if (priv->rxpackets != NULL) {
498 #if SLIP_RX_QUEUE
499 /* queue multiple pbufs */
500 struct pbuf *q = p;
501 while (q->next != NULL) {
502 q = q->next;
503 }
504 q->next = p;
505 } else {
506 #else /* SLIP_RX_QUEUE */
507 pbuf_free(priv->rxpackets);
508 }
509 {
510 #endif /* SLIP_RX_QUEUE */
511 priv->rxpackets = p;
512 }
513 SYS_ARCH_UNPROTECT(old_level);
514 }
515 }
516
517 /**
518 * @ingroup slipif
519 * Process a received byte, completed packets are put on a queue that is
520 * fed into IP through slipif_process_rxqueue().
521 *
522 * This function can be called from ISR if SYS_LIGHTWEIGHT_PROT is enabled.
523 *
524 * @param netif The lwip network interface structure for this slipif
525 * @param data received character
526 */
527 void
slipif_received_byte(struct netif * netif,u8_t data)528 slipif_received_byte(struct netif *netif, u8_t data)
529 {
530 LWIP_ASSERT("netif != NULL", (netif != NULL));
531 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
532 slipif_rxbyte_enqueue(netif, data);
533 }
534
535 /**
536 * @ingroup slipif
537 * Process multiple received byte, completed packets are put on a queue that is
538 * fed into IP through slipif_process_rxqueue().
539 *
540 * This function can be called from ISR if SYS_LIGHTWEIGHT_PROT is enabled.
541 *
542 * @param netif The lwip network interface structure for this slipif
543 * @param data received character
544 * @param len Number of received characters
545 */
546 void
slipif_received_bytes(struct netif * netif,u8_t * data,u8_t len)547 slipif_received_bytes(struct netif *netif, u8_t *data, u8_t len)
548 {
549 u8_t i;
550 u8_t *rxdata = data;
551 LWIP_ASSERT("netif != NULL", (netif != NULL));
552 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
553
554 for (i = 0; i < len; i++, rxdata++) {
555 slipif_rxbyte_enqueue(netif, *rxdata);
556 }
557 }
558 #endif /* SLIP_RX_FROM_ISR */
559