lwip_slipif.c

00001 /**
00002  * @file
00003  * SLIP Interface
00004  *
00005  */
00006 
00007 /*
00008  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00009  * All rights reserved.
00010  *
00011  * Redistribution and use in source and binary forms, with or without
00012  * modification, are permitted provided that the following conditions
00013  * are met:
00014  * 1. Redistributions of source code must retain the above copyright
00015  *    notice, this list of conditions and the following disclaimer.
00016  * 2. Redistributions in binary form must reproduce the above copyright
00017  *    notice, this list of conditions and the following disclaimer in the
00018  *    documentation and/or other materials provided with the distribution.
00019  * 3. Neither the name of the Institute nor the names of its contributors
00020  *    may be used to endorse or promote products derived from this software
00021  *    without specific prior written permission.
00022  *
00023  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
00024  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00025  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00026  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
00027  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00028  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00029  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00030  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00031  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00032  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00033  * SUCH DAMAGE.
00034  *
00035  * This file is built upon the file: src/arch/rtxc/netif/sioslip.c
00036  *
00037  * Author: Magnus Ivarsson <magnus.ivarsson(at)volvo.com>
00038  *         Simon Goldschmidt
00039  */
00040 
00041 
00042 /**
00043  * @defgroup slipif SLIP netif
00044  * @ingroup addons
00045  * 
00046  * This is an arch independent SLIP netif. The specific serial hooks must be
00047  * provided by another file. They are sio_open, sio_read/sio_tryread and sio_send
00048  * 
00049  * Usage: This netif can be used in three ways:\n
00050  *        1) For NO_SYS==0, an RX thread can be used which blocks on sio_read()
00051  *           until data is received.\n
00052  *        2) In your main loop, call slipif_poll() to check for new RX bytes,
00053  *           completed packets are fed into netif->input().\n
00054  *        3) Call slipif_received_byte[s]() from your serial RX ISR and
00055  *           slipif_process_rxqueue() from your main loop. ISR level decodes
00056  *           packets and puts completed packets on a queue which is fed into
00057  *           the stack from the main loop (needs SYS_LIGHTWEIGHT_PROT for
00058  *           pbuf_alloc to work on ISR level!).
00059  *
00060  */
00061 
00062 #include "netif/slipif.h"
00063 #include "lwip/opt.h"
00064 
00065 #include "lwip/def.h"
00066 #include "lwip/pbuf.h"
00067 #include "lwip/stats.h"
00068 #include "lwip/snmp.h"
00069 #include "lwip/sys.h"
00070 #include "lwip/sio.h"
00071 
00072 #define SLIP_END     0xC0 /* 0300: start and end of every packet */
00073 #define SLIP_ESC     0xDB /* 0333: escape start (one byte escaped data follows) */
00074 #define SLIP_ESC_END 0xDC /* 0334: following escape: original byte is 0xC0 (END) */
00075 #define SLIP_ESC_ESC 0xDD /* 0335: following escape: original byte is 0xDB (ESC) */
00076 
00077 /** Maximum packet size that is received by this netif */
00078 #ifndef SLIP_MAX_SIZE
00079 #define SLIP_MAX_SIZE 1500
00080 #endif
00081 
00082 /** Define this to the interface speed for SNMP
00083  * (sio_fd is the sio_fd_t returned by sio_open).
00084  * The default value of zero means 'unknown'.
00085  */
00086 #ifndef SLIP_SIO_SPEED
00087 #define SLIP_SIO_SPEED(sio_fd) 0
00088 #endif
00089 
00090 enum slipif_recv_state {
00091     SLIP_RECV_NORMAL,
00092     SLIP_RECV_ESCAPE
00093 };
00094 
00095 struct slipif_priv {
00096   sio_fd_t sd;
00097   /* q is the whole pbuf chain for a packet, p is the current pbuf in the chain */
00098   struct pbuf *p, *q;
00099   u8_t state;
00100   u16_t i, recved;
00101 #if SLIP_RX_FROM_ISR
00102   struct pbuf *rxpackets;
00103 #endif
00104 };
00105 
00106 /**
00107  * Send a pbuf doing the necessary SLIP encapsulation
00108  *
00109  * Uses the serial layer's sio_send()
00110  *
00111  * @param netif the lwip network interface structure for this slipif
00112  * @param p the pbuf chain packet to send
00113  * @return always returns ERR_OK since the serial layer does not provide return values
00114  */
00115 static err_t
00116 slipif_output(struct netif *netif, struct pbuf *p)
00117 {
00118   struct slipif_priv *priv;
00119   struct pbuf *q;
00120   u16_t i;
00121   u8_t c;
00122 
00123   LWIP_ASSERT("netif != NULL", (netif != NULL));
00124   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
00125   LWIP_ASSERT("p != NULL", (p != NULL));
00126 
00127   LWIP_DEBUGF(SLIP_DEBUG, ("slipif_output(%"U16_F"): sending %"U16_F" bytes\n", (u16_t)netif->num, p->tot_len));
00128   priv = (struct slipif_priv *)netif->state;
00129 
00130   /* Send pbuf out on the serial I/O device. */
00131   /* Start with packet delimiter. */
00132   sio_send(SLIP_END, priv->sd);
00133 
00134   for (q = p; q != NULL; q = q->next) {
00135     for (i = 0; i < q->len; i++) {
00136       c = ((u8_t *)q->payload)[i];
00137       switch (c) {
00138       case SLIP_END:
00139         /* need to escape this byte (0xC0 -> 0xDB, 0xDC) */
00140         sio_send(SLIP_ESC, priv->sd);
00141         sio_send(SLIP_ESC_END, priv->sd);
00142         break;
00143       case SLIP_ESC:
00144         /* need to escape this byte (0xDB -> 0xDB, 0xDD) */
00145         sio_send(SLIP_ESC, priv->sd);
00146         sio_send(SLIP_ESC_ESC, priv->sd);
00147         break;
00148       default:
00149         /* normal byte - no need for escaping */
00150         sio_send(c, priv->sd);
00151         break;
00152       }
00153     }
00154   }
00155   /* End with packet delimiter. */
00156   sio_send(SLIP_END, priv->sd);
00157   return ERR_OK;
00158 }
00159 
00160 #if LWIP_IPV4
00161 /**
00162  * Send a pbuf doing the necessary SLIP encapsulation
00163  *
00164  * Uses the serial layer's sio_send()
00165  *
00166  * @param netif the lwip network interface structure for this slipif
00167  * @param p the pbuf chain packet to send
00168  * @param ipaddr the ip address to send the packet to (not used for slipif)
00169  * @return always returns ERR_OK since the serial layer does not provide return values
00170  */
00171 static err_t
00172 slipif_output_v4(struct netif *netif, struct pbuf *p, const ip4_addr_t *ipaddr)
00173 {
00174   LWIP_UNUSED_ARG(ipaddr);
00175   return slipif_output(netif, p);
00176 }
00177 #endif /* LWIP_IPV4 */
00178 
00179 #if LWIP_IPV6
00180 /**
00181  * Send a pbuf doing the necessary SLIP encapsulation
00182  *
00183  * Uses the serial layer's sio_send()
00184  *
00185  * @param netif the lwip network interface structure for this slipif
00186  * @param p the pbuf chain packet to send
00187  * @param ipaddr the ip address to send the packet to (not used for slipif)
00188  * @return always returns ERR_OK since the serial layer does not provide return values
00189  */
00190 static err_t
00191 slipif_output_v6(struct netif *netif, struct pbuf *p, const ip6_addr_t *ipaddr)
00192 {
00193   LWIP_UNUSED_ARG(ipaddr);
00194   return slipif_output(netif, p);
00195 }
00196 #endif /* LWIP_IPV6 */
00197 
00198 /**
00199  * Handle the incoming SLIP stream character by character
00200  *
00201  * @param netif the lwip network interface structure for this slipif
00202  * @param c received character (multiple calls to this function will
00203  *        return a complete packet, NULL is returned before - used for polling)
00204  * @return The IP packet when SLIP_END is received
00205  */
00206 static struct pbuf*
00207 slipif_rxbyte(struct netif *netif, u8_t c)
00208 {
00209   struct slipif_priv *priv;
00210   struct pbuf *t;
00211 
00212   LWIP_ASSERT("netif != NULL", (netif != NULL));
00213   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
00214 
00215   priv = (struct slipif_priv *)netif->state;
00216 
00217   switch (priv->state) {
00218   case SLIP_RECV_NORMAL:
00219     switch (c) {
00220     case SLIP_END:
00221       if (priv->recved > 0) {
00222         /* Received whole packet. */
00223         /* Trim the pbuf to the size of the received packet. */
00224         pbuf_realloc(priv->q, priv->recved);
00225 
00226         LINK_STATS_INC(link.recv);
00227 
00228         LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet (%"U16_F" bytes)\n", priv->recved));
00229         t = priv->q;
00230         priv->p = priv->q = NULL;
00231         priv->i = priv->recved = 0;
00232         return t;
00233       }
00234       return NULL;
00235     case SLIP_ESC:
00236       priv->state = SLIP_RECV_ESCAPE;
00237       return NULL;
00238     default:
00239       break;
00240     } /* end switch (c) */
00241     break;
00242   case SLIP_RECV_ESCAPE:
00243     /* un-escape END or ESC bytes, leave other bytes
00244        (although that would be a protocol error) */
00245     switch (c) {
00246     case SLIP_ESC_END:
00247       c = SLIP_END;
00248       break;
00249     case SLIP_ESC_ESC:
00250       c = SLIP_ESC;
00251       break;
00252     default:
00253       break;
00254     }
00255     priv->state = SLIP_RECV_NORMAL;
00256     break;
00257   default:
00258     break;
00259   } /* end switch (priv->state) */
00260 
00261   /* byte received, packet not yet completely received */
00262   if (priv->p == NULL) {
00263     /* allocate a new pbuf */
00264     LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
00265     priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN - PBUF_LINK_ENCAPSULATION_HLEN), PBUF_POOL);
00266 
00267     if (priv->p == NULL) {
00268       LINK_STATS_INC(link.drop);
00269       LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
00270       /* don't process any further since we got no pbuf to receive to */
00271       return NULL;
00272     }
00273 
00274     if (priv->q != NULL) {
00275       /* 'chain' the pbuf to the existing chain */
00276       pbuf_cat(priv->q, priv->p);
00277     } else {
00278       /* p is the first pbuf in the chain */
00279       priv->q = priv->p;
00280     }
00281   }
00282 
00283   /* this automatically drops bytes if > SLIP_MAX_SIZE */
00284   if ((priv->p != NULL) && (priv->recved <= SLIP_MAX_SIZE)) {
00285     ((u8_t *)priv->p->payload)[priv->i] = c;
00286     priv->recved++;
00287     priv->i++;
00288     if (priv->i >= priv->p->len) {
00289       /* on to the next pbuf */
00290       priv->i = 0;
00291       if (priv->p->next != NULL && priv->p->next->len > 0) {
00292         /* p is a chain, on to the next in the chain */
00293           priv->p = priv->p->next;
00294       } else {
00295         /* p is a single pbuf, set it to NULL so next time a new
00296          * pbuf is allocated */
00297           priv->p = NULL;
00298       }
00299     }
00300   }
00301   return NULL;
00302 }
00303 
00304 /** Like slipif_rxbyte, but passes completed packets to netif->input
00305  *
00306  * @param netif The lwip network interface structure for this slipif
00307  * @param data received character
00308  */
00309 static void
00310 slipif_rxbyte_input(struct netif *netif, u8_t c)
00311 {
00312   struct pbuf *p;
00313   p = slipif_rxbyte(netif, c);
00314   if (p != NULL) {
00315     if (netif->input(p, netif) != ERR_OK) {
00316       pbuf_free(p);
00317     }
00318   }
00319 }
00320 
00321 #if SLIP_USE_RX_THREAD
00322 /**
00323  * The SLIP input thread.
00324  *
00325  * Feed the IP layer with incoming packets
00326  *
00327  * @param nf the lwip network interface structure for this slipif
00328  */
00329 static void
00330 slipif_loop_thread(void *nf)
00331 {
00332   u8_t c;
00333   struct netif *netif = (struct netif *)nf;
00334   struct slipif_priv *priv = (struct slipif_priv *)netif->state;
00335 
00336   while (1) {
00337     if (sio_read(priv->sd, &c, 1) > 0) {
00338       slipif_rxbyte_input(netif, c);
00339     }
00340   }
00341 }
00342 #endif /* SLIP_USE_RX_THREAD */
00343 
00344 /**
00345  * SLIP netif initialization
00346  *
00347  * Call the arch specific sio_open and remember
00348  * the opened device in the state field of the netif.
00349  *
00350  * @param netif the lwip network interface structure for this slipif
00351  * @return ERR_OK if serial line could be opened,
00352  *         ERR_MEM if no memory could be allocated,
00353  *         ERR_IF is serial line couldn't be opened
00354  *
00355  * @note netif->num must contain the number of the serial port to open
00356  *       (0 by default). If netif->state is != NULL, it is interpreted as an
00357  *       u8_t pointer pointing to the serial port number instead of netif->num.
00358  *
00359  */
00360 err_t
00361 slipif_init(struct netif *netif)
00362 {
00363   struct slipif_priv *priv;
00364   u8_t sio_num;
00365 
00366   LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)netif->num));
00367 
00368   /* Allocate private data */
00369   priv = (struct slipif_priv *)mem_malloc(sizeof(struct slipif_priv));
00370   if (!priv) {
00371     return ERR_MEM;
00372   }
00373 
00374   netif->name[0] = 's';
00375   netif->name[1] = 'l';
00376 #if LWIP_IPV4
00377   netif->output = slipif_output_v4;
00378 #endif /* LWIP_IPV4 */
00379 #if LWIP_IPV6
00380   netif->output_ip6 = slipif_output_v6;
00381 #endif /* LWIP_IPV6 */
00382   netif->mtu = SLIP_MAX_SIZE;
00383 
00384   /* netif->state or netif->num contain the port number */
00385   if (netif->state != NULL) {
00386     sio_num = *(u8_t*)netif->state;
00387   } else {
00388     sio_num = netif->num;
00389   }
00390   /* Try to open the serial port. */
00391   priv->sd = sio_open(sio_num);
00392   if (!priv->sd) {
00393     /* Opening the serial port failed. */
00394     mem_free(priv);
00395     return ERR_IF;
00396   }
00397 
00398   /* Initialize private data */
00399   priv->p = NULL;
00400   priv->q = NULL;
00401   priv->state = SLIP_RECV_NORMAL;
00402   priv->i = 0;
00403   priv->recved = 0;
00404 #if SLIP_RX_FROM_ISR
00405   priv->rxpackets = NULL;
00406 #endif
00407 
00408   netif->state = priv;
00409 
00410   /* initialize the snmp variables and counters inside the struct netif */
00411   MIB2_INIT_NETIF(netif, snmp_ifType_slip, SLIP_SIO_SPEED(priv->sd));
00412 
00413 #if SLIP_USE_RX_THREAD
00414   /* Create a thread to poll the serial line. */
00415   sys_thread_new(SLIPIF_THREAD_NAME, slipif_loop_thread, netif,
00416     SLIPIF_THREAD_STACKSIZE, SLIPIF_THREAD_PRIO);
00417 #endif /* SLIP_USE_RX_THREAD */
00418   return ERR_OK;
00419 }
00420 
00421 /**
00422  * Polls the serial device and feeds the IP layer with incoming packets.
00423  *
00424  * @param netif The lwip network interface structure for this slipif
00425  */
00426 void
00427 slipif_poll(struct netif *netif)
00428 {
00429   u8_t c;
00430   struct slipif_priv *priv;
00431 
00432   LWIP_ASSERT("netif != NULL", (netif != NULL));
00433   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
00434 
00435   priv = (struct slipif_priv *)netif->state;
00436 
00437   while (sio_tryread(priv->sd, &c, 1) > 0) {
00438     slipif_rxbyte_input(netif, c);
00439   }
00440 }
00441 
00442 #if SLIP_RX_FROM_ISR
00443 /**
00444  * Feeds the IP layer with incoming packets that were receive
00445  *
00446  * @param netif The lwip network interface structure for this slipif
00447  */
00448 void
00449 slipif_process_rxqueue(struct netif *netif)
00450 {
00451   struct slipif_priv *priv;
00452   SYS_ARCH_DECL_PROTECT(old_level);
00453 
00454   LWIP_ASSERT("netif != NULL", (netif != NULL));
00455   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
00456 
00457   priv = (struct slipif_priv *)netif->state;
00458 
00459   SYS_ARCH_PROTECT(old_level);
00460   while (priv->rxpackets != NULL) {
00461     struct pbuf *p = priv->rxpackets;
00462 #if SLIP_RX_QUEUE
00463     /* dequeue packet */
00464     struct pbuf *q = p;
00465     while ((q->len != q->tot_len) && (q->next != NULL)) {
00466       q = q->next;
00467     }
00468     priv->rxpackets = q->next;
00469     q->next = NULL;
00470 #else /* SLIP_RX_QUEUE */
00471     priv->rxpackets = NULL;
00472 #endif /* SLIP_RX_QUEUE */
00473     SYS_ARCH_UNPROTECT(old_level);
00474     if (netif->input(p, netif) != ERR_OK) {
00475       pbuf_free(p);
00476     }
00477     SYS_ARCH_PROTECT(old_level);
00478   }
00479 }
00480 
00481 /** Like slipif_rxbyte, but queues completed packets.
00482  *
00483  * @param netif The lwip network interface structure for this slipif
00484  * @param data Received serial byte
00485  */
00486 static void
00487 slipif_rxbyte_enqueue(struct netif *netif, u8_t data)
00488 {
00489   struct pbuf *p;
00490   struct slipif_priv *priv = (struct slipif_priv *)netif->state;
00491   SYS_ARCH_DECL_PROTECT(old_level);
00492 
00493   p = slipif_rxbyte(netif, data);
00494   if (p != NULL) {
00495     SYS_ARCH_PROTECT(old_level);
00496     if (priv->rxpackets != NULL) {
00497 #if SLIP_RX_QUEUE
00498       /* queue multiple pbufs */
00499       struct pbuf *q = p;
00500       while (q->next != NULL) {
00501         q = q->next;
00502       }
00503       q->next = p;
00504     } else {
00505 #else /* SLIP_RX_QUEUE */
00506       pbuf_free(priv->rxpackets);
00507     }
00508     {
00509 #endif /* SLIP_RX_QUEUE */
00510       priv->rxpackets = p;
00511     }
00512     SYS_ARCH_UNPROTECT(old_level);
00513   }
00514 }
00515 
00516 /**
00517  * Process a received byte, completed packets are put on a queue that is
00518  * fed into IP through slipif_process_rxqueue().
00519  *
00520  * This function can be called from ISR if SYS_LIGHTWEIGHT_PROT is enabled.
00521  *
00522  * @param netif The lwip network interface structure for this slipif
00523  * @param data received character
00524  */
00525 void
00526 slipif_received_byte(struct netif *netif, u8_t data)
00527 {
00528   LWIP_ASSERT("netif != NULL", (netif != NULL));
00529   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
00530   slipif_rxbyte_enqueue(netif, data);
00531 }
00532 
00533 /**
00534  * Process multiple received byte, completed packets are put on a queue that is
00535  * fed into IP through slipif_process_rxqueue().
00536  *
00537  * This function can be called from ISR if SYS_LIGHTWEIGHT_PROT is enabled.
00538  *
00539  * @param netif The lwip network interface structure for this slipif
00540  * @param data received character
00541  * @param len Number of received characters
00542  */
00543 void
00544 slipif_received_bytes(struct netif *netif, u8_t *data, u8_t len)
00545 {
00546   u8_t i;
00547   u8_t *rxdata = data;
00548   LWIP_ASSERT("netif != NULL", (netif != NULL));
00549   LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
00550 
00551   for (i = 0; i < len; i++, rxdata++) {
00552     slipif_rxbyte_enqueue(netif, *rxdata);
00553   }
00554 }
00555 #endif /* SLIP_RX_FROM_ISR */