lib/liblwip/netif/ethernetif.c

   1 /**
   2  * @file
   3  * Ethernet Interface Skeleton
   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 modification,
  12  * are permitted provided that the following conditions are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright notice,
  15  *    this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright notice,
  17  *    this list of conditions and the following disclaimer in the documentation
  18  *    and/or other materials provided with the distribution.
  19  * 3. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  25  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  27  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  31  * OF SUCH DAMAGE.
  32  *
  33  * This file is part of the lwIP TCP/IP stack.
  34  *
  35  * Author: Adam Dunkels <adam@sics.se>
  36  *
  37  */
  38
  39 /*
  40  * This file is a skeleton for developing Ethernet network interface
  41  * drivers for lwIP. Add code to the low_level functions and do a
  42  * search-and-replace for the word "ethernetif" to replace it with
  43  * something that better describes your network interface.
  44  */
  45
  46 #include "lwip/opt.h"
  47
  48 #if 0 /* don't build, this is only a skeleton, see previous comment */
  49
  50 #include "lwip/def.h"
  51 #include "lwip/mem.h"
  52 #include "lwip/pbuf.h"
  53 #include "lwip/sys.h"
  54 #include <lwip/stats.h>
  55 #include <lwip/snmp.h>
  56 #include "netif/etharp.h"
  57 #include "netif/ppp_oe.h"
  58
  59 /* Define those to better describe your network interface. */
  60 #define IFNAME0 'e'
  61 #define IFNAME1 'n'
  62
  63 /**
  64  * Helper struct to hold private data used to operate your ethernet interface.
  65  * Keeping the ethernet address of the MAC in this struct is not necessary
  66  * as it is already kept in the struct netif.
  67  * But this is only an example, anyway...
  68  */
  69 struct ethernetif {
  70   struct eth_addr *ethaddr;
  71   /* Add whatever per-interface state that is needed here. */
  72 };
  73
  74 /* Forward declarations. */
  75 static void  ethernetif_input(struct netif *netif);
  76
  77 /**
  78  * In this function, the hardware should be initialized.
  79  * Called from ethernetif_init().
  80  *
  81  * @param netif the already initialized lwip network interface structure
  82  *        for this ethernetif
  83  */
  84 static void
  85 low_level_init(struct netif *netif)
  86 {
  87   struct ethernetif *ethernetif = netif->state;
  88
  89   /* set MAC hardware address length */
  90   netif->hwaddr_len = ETHARP_HWADDR_LEN;
  91
  92   /* set MAC hardware address */
  93   netif->hwaddr[0] = ;
  94   ...
  95   netif->hwaddr[5] = ;
  96
  97   /* maximum transfer unit */
  98   netif->mtu = 1500;
  99
 100   /* device capabilities */
 101   /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
 102   netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;
 103
 104   /* Do whatever else is needed to initialize interface. */
 105 }
 106
 107 /**
 108  * This function should do the actual transmission of the packet. The packet is
 109  * contained in the pbuf that is passed to the function. This pbuf
 110  * might be chained.
 111  *
 112  * @param netif the lwip network interface structure for this ethernetif
 113  * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
 114  * @return ERR_OK if the packet could be sent
 115  *         an err_t value if the packet couldn't be sent
 116  *
 117  * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
 118  *       strange results. You might consider waiting for space in the DMA queue
 119  *       to become availale since the stack doesn't retry to send a packet
 120  *       dropped because of memory failure (except for the TCP timers).
 121  */
 122
 123 static err_t
 124 low_level_output(struct netif *netif, struct pbuf *p)
 125 {
 126   struct ethernetif *ethernetif = netif->state;
 127   struct pbuf *q;
 128
 129   initiate transfer();
 130
 131 #if ETH_PAD_SIZE
 132   pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
 133 #endif
 134
 135   for(q = p; q != NULL; q = q->next) {
 136     /* Send the data from the pbuf to the interface, one pbuf at a
 137        time. The size of the data in each pbuf is kept in the ->len
 138        variable. */
 139     send data from(q->payload, q->len);
 140   }
 141
 142   signal that packet should be sent();
 143
 144 #if ETH_PAD_SIZE
 145   pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
 146 #endif
 147
 148   LINK_STATS_INC(link.xmit);
 149
 150   return ERR_OK;
 151 }
 152
 153 /**
 154  * Should allocate a pbuf and transfer the bytes of the incoming
 155  * packet from the interface into the pbuf.
 156  *
 157  * @param netif the lwip network interface structure for this ethernetif
 158  * @return a pbuf filled with the received packet (including MAC header)
 159  *         NULL on memory error
 160  */
 161 static struct pbuf *
 162 low_level_input(struct netif *netif)
 163 {
 164   struct ethernetif *ethernetif = netif->state;
 165   struct pbuf *p, *q;
 166   u16_t len;
 167
 168   /* Obtain the size of the packet and put it into the "len"
 169      variable. */
 170   len = ;
 171
 172 #if ETH_PAD_SIZE
 173   len += ETH_PAD_SIZE; /* allow room for Ethernet padding */
 174 #endif
 175
 176   /* We allocate a pbuf chain of pbufs from the pool. */
 177   p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
 178
 179   if (p != NULL) {
 180
 181 #if ETH_PAD_SIZE
 182     pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
 183 #endif
 184
 185     /* We iterate over the pbuf chain until we have read the entire
 186      * packet into the pbuf. */
 187     for(q = p; q != NULL; q = q->next) {
 188       /* Read enough bytes to fill this pbuf in the chain. The
 189        * available data in the pbuf is given by the q->len
 190        * variable.
 191        * This does not necessarily have to be a memcpy, you can also preallocate
 192        * pbufs for a DMA-enabled MAC and after receiving truncate it to the
 193        * actually received size. In this case, ensure the tot_len member of the
 194        * pbuf is the sum of the chained pbuf len members.
 195        */
 196       read data into(q->payload, q->len);
 197     }
 198     acknowledge that packet has been read();
 199
 200 #if ETH_PAD_SIZE
 201     pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
 202 #endif
 203
 204     LINK_STATS_INC(link.recv);
 205   } else {
 206     drop packet();
 207     LINK_STATS_INC(link.memerr);
 208     LINK_STATS_INC(link.drop);
 209   }
 210
 211   return p;
 212 }
 213
 214 /**
 215  * This function should be called when a packet is ready to be read
 216  * from the interface. It uses the function low_level_input() that
 217  * should handle the actual reception of bytes from the network
 218  * interface. Then the type of the received packet is determined and
 219  * the appropriate input function is called.
 220  *
 221  * @param netif the lwip network interface structure for this ethernetif
 222  */
 223 static void
 224 ethernetif_input(struct netif *netif)
 225 {
 226   struct ethernetif *ethernetif;
 227   struct eth_hdr *ethhdr;
 228   struct pbuf *p;
 229
 230   ethernetif = netif->state;
 231
 232   /* move received packet into a new pbuf */
 233   p = low_level_input(netif);
 234   /* no packet could be read, silently ignore this */
 235   if (p == NULL) return;
 236   /* points to packet payload, which starts with an Ethernet header */
 237   ethhdr = p->payload;
 238
 239   switch (htons(ethhdr->type)) {
 240   /* IP or ARP packet? */
 241   case ETHTYPE_IP:
 242   case ETHTYPE_ARP:
 243 #if PPPOE_SUPPORT
 244   /* PPPoE packet? */
 245   case ETHTYPE_PPPOEDISC:
 246   case ETHTYPE_PPPOE:
 247 #endif /* PPPOE_SUPPORT */
 248     /* full packet send to tcpip_thread to process */
 249     if (netif->input(p, netif)!=ERR_OK)
 250      { LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
 251        pbuf_free(p);
 252        p = NULL;
 253      }
 254     break;
 255
 256   default:
 257     pbuf_free(p);
 258     p = NULL;
 259     break;
 260   }
 261 }
 262
 263 /**
 264  * Should be called at the beginning of the program to set up the
 265  * network interface. It calls the function low_level_init() to do the
 266  * actual setup of the hardware.
 267  *
 268  * This function should be passed as a parameter to netif_add().
 269  *
 270  * @param netif the lwip network interface structure for this ethernetif
 271  * @return ERR_OK if the loopif is initialized
 272  *         ERR_MEM if private data couldn't be allocated
 273  *         any other err_t on error
 274  */
 275 err_t
 276 ethernetif_init(struct netif *netif)
 277 {
 278   struct ethernetif *ethernetif;
 279
 280   LWIP_ASSERT("netif != NULL", (netif != NULL));
 281
 282   ethernetif = mem_malloc(sizeof(struct ethernetif));
 283   if (ethernetif == NULL) {
 284     LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));
 285     return ERR_MEM;
 286   }
 287
 288 #if LWIP_NETIF_HOSTNAME
 289   /* Initialize interface hostname */
 290   netif->hostname = "lwip";
 291 #endif /* LWIP_NETIF_HOSTNAME */
 292
 293   /*
 294    * Initialize the snmp variables and counters inside the struct netif.
 295    * The last argument should be replaced with your link speed, in units
 296    * of bits per second.
 297    */
 298   NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED_OF_YOUR_NETIF_IN_BPS);
 299
 300   netif->state = ethernetif;
 301   netif->name[0] = IFNAME0;
 302   netif->name[1] = IFNAME1;
 303   /* We directly use etharp_output() here to save a function call.
 304    * You can instead declare your own function an call etharp_output()
 305    * from it if you have to do some checks before sending (e.g. if link
 306    * is available...) */
 307   netif->output = etharp_output;
 308   netif->linkoutput = low_level_output;
 309
 310   ethernetif->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);
 311
 312   /* initialize the hardware */
 313   low_level_init(netif);
 314
 315   return ERR_OK;
 316 }
 317
 318 #endif /* 0 */