lib/liblwip/netif/slipif.c

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