minix/lib/liblwip/dist/src/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
  41
  42 /**
  43  * @defgroup slipif SLIP netif
  44  * @ingroup addons
  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:\n
  50  *        1) For NO_SYS==0, an RX thread can be used which blocks on sio_read()
  51  *           until data is received.\n
  52  *        2) In your main loop, call slipif_poll() to check for new RX bytes,
  53  *           completed packets are fed into netif->input().\n
  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
 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
 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
 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*
 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
 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
 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  * SLIP netif initialization
 346  *
 347  * Call the arch specific sio_open and remember
 348  * the opened device in the state field of the netif.
 349  *
 350  * @param netif the lwip network interface structure for this slipif
 351  * @return ERR_OK if serial line could be opened,
 352  *         ERR_MEM if no memory could be allocated,
 353  *         ERR_IF is serial line couldn't be opened
 354  *
 355  * @note If netif->state is interpreted as an u8_t serial port number.
 356  *
 357  */
 358 err_t
 359 slipif_init(struct netif *netif)
 360 {
 361   struct slipif_priv *priv;
 362   u8_t sio_num;
 363
 364   /* netif->state contains serial port number */
 365   sio_num = LWIP_PTR_NUMERIC_CAST(u8_t, netif->state);
 366
 367   LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)sio_num));
 368
 369   /* Allocate private data */
 370   priv = (struct slipif_priv *)mem_malloc(sizeof(struct slipif_priv));
 371   if (!priv) {
 372     return ERR_MEM;
 373   }
 374
 375   netif->name[0] = 's';
 376   netif->name[1] = 'l';
 377 #if LWIP_IPV4
 378   netif->output = slipif_output_v4;
 379 #endif /* LWIP_IPV4 */
 380 #if LWIP_IPV6
 381   netif->output_ip6 = slipif_output_v6;
 382 #endif /* LWIP_IPV6 */
 383   netif->mtu = SLIP_MAX_SIZE;
 384
 385   /* Try to open the serial port. */
 386   priv->sd = sio_open(sio_num);
 387   if (!priv->sd) {
 388     /* Opening the serial port failed. */
 389     mem_free(priv);
 390     return ERR_IF;
 391   }
 392
 393   /* Initialize private data */
 394   priv->p = NULL;
 395   priv->q = NULL;
 396   priv->state = SLIP_RECV_NORMAL;
 397   priv->i = 0;
 398   priv->recved = 0;
 399 #if SLIP_RX_FROM_ISR
 400   priv->rxpackets = NULL;
 401 #endif
 402
 403   netif->state = priv;
 404
 405   /* initialize the snmp variables and counters inside the struct netif */
 406   MIB2_INIT_NETIF(netif, snmp_ifType_slip, SLIP_SIO_SPEED(priv->sd));
 407
 408 #if SLIP_USE_RX_THREAD
 409   /* Create a thread to poll the serial line. */
 410   sys_thread_new(SLIPIF_THREAD_NAME, slipif_loop_thread, netif,
 411     SLIPIF_THREAD_STACKSIZE, SLIPIF_THREAD_PRIO);
 412 #endif /* SLIP_USE_RX_THREAD */
 413   return ERR_OK;
 414 }
 415
 416 /**
 417  * Polls the serial device and feeds the IP layer with incoming packets.
 418  *
 419  * @param netif The lwip network interface structure for this slipif
 420  */
 421 void
 422 slipif_poll(struct netif *netif)
 423 {
 424   u8_t c;
 425   struct slipif_priv *priv;
 426
 427   LWIP_ASSERT("netif != NULL", (netif != NULL));
 428   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
 429
 430   priv = (struct slipif_priv *)netif->state;
 431
 432   while (sio_tryread(priv->sd, &c, 1) > 0) {
 433     slipif_rxbyte_input(netif, c);
 434   }
 435 }
 436
 437 #if SLIP_RX_FROM_ISR
 438 /**
 439  * Feeds the IP layer with incoming packets that were receive
 440  *
 441  * @param netif The lwip network interface structure for this slipif
 442  */
 443 void
 444 slipif_process_rxqueue(struct netif *netif)
 445 {
 446   struct slipif_priv *priv;
 447   SYS_ARCH_DECL_PROTECT(old_level);
 448
 449   LWIP_ASSERT("netif != NULL", (netif != NULL));
 450   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
 451
 452   priv = (struct slipif_priv *)netif->state;
 453
 454   SYS_ARCH_PROTECT(old_level);
 455   while (priv->rxpackets != NULL) {
 456     struct pbuf *p = priv->rxpackets;
 457 #if SLIP_RX_QUEUE
 458     /* dequeue packet */
 459     struct pbuf *q = p;
 460     while ((q->len != q->tot_len) && (q->next != NULL)) {
 461       q = q->next;
 462     }
 463     priv->rxpackets = q->next;
 464     q->next = NULL;
 465 #else /* SLIP_RX_QUEUE */
 466     priv->rxpackets = NULL;
 467 #endif /* SLIP_RX_QUEUE */
 468     SYS_ARCH_UNPROTECT(old_level);
 469     if (netif->input(p, netif) != ERR_OK) {
 470       pbuf_free(p);
 471     }
 472     SYS_ARCH_PROTECT(old_level);
 473   }
 474 }
 475
 476 /** Like slipif_rxbyte, but queues completed packets.
 477  *
 478  * @param netif The lwip network interface structure for this slipif
 479  * @param data Received serial byte
 480  */
 481 static void
 482 slipif_rxbyte_enqueue(struct netif *netif, u8_t data)
 483 {
 484   struct pbuf *p;
 485   struct slipif_priv *priv = (struct slipif_priv *)netif->state;
 486   SYS_ARCH_DECL_PROTECT(old_level);
 487
 488   p = slipif_rxbyte(netif, data);
 489   if (p != NULL) {
 490     SYS_ARCH_PROTECT(old_level);
 491     if (priv->rxpackets != NULL) {
 492 #if SLIP_RX_QUEUE
 493       /* queue multiple pbufs */
 494       struct pbuf *q = p;
 495       while (q->next != NULL) {
 496         q = q->next;
 497       }
 498       q->next = p;
 499     } else {
 500 #else /* SLIP_RX_QUEUE */
 501       pbuf_free(priv->rxpackets);
 502     }
 503     {
 504 #endif /* SLIP_RX_QUEUE */
 505       priv->rxpackets = p;
 506     }
 507     SYS_ARCH_UNPROTECT(old_level);
 508   }
 509 }
 510
 511 /**
 512  * Process a received byte, completed packets are put on a queue that is
 513  * fed into IP through slipif_process_rxqueue().
 514  *
 515  * This function can be called from ISR if SYS_LIGHTWEIGHT_PROT is enabled.
 516  *
 517  * @param netif The lwip network interface structure for this slipif
 518  * @param data received character
 519  */
 520 void
 521 slipif_received_byte(struct netif *netif, u8_t data)
 522 {
 523   LWIP_ASSERT("netif != NULL", (netif != NULL));
 524   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
 525   slipif_rxbyte_enqueue(netif, data);
 526 }
 527
 528 /**
 529  * Process multiple received byte, completed packets are put on a queue that is
 530  * fed into IP through slipif_process_rxqueue().
 531  *
 532  * This function can be called from ISR if SYS_LIGHTWEIGHT_PROT is enabled.
 533  *
 534  * @param netif The lwip network interface structure for this slipif
 535  * @param data received character
 536  * @param len Number of received characters
 537  */
 538 void
 539 slipif_received_bytes(struct netif *netif, u8_t *data, u8_t len)
 540 {
 541   u8_t i;
 542   u8_t *rxdata = data;
 543   LWIP_ASSERT("netif != NULL", (netif != NULL));
 544   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
 545
 546   for (i = 0; i < len; i++, rxdata++) {
 547     slipif_rxbyte_enqueue(netif, *rxdata);
 548   }
 549 }
 550 #endif /* SLIP_RX_FROM_ISR */