lwip_ethernetif.c

00001 /**
00002  * @file
00003  * Ethernet Interface Skeleton
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 modification,
00012  * are permitted provided that the following conditions are met:
00013  *
00014  * 1. Redistributions of source code must retain the above copyright notice,
00015  *    this list of conditions and the following disclaimer.
00016  * 2. Redistributions in binary form must reproduce the above copyright notice,
00017  *    this list of conditions and the following disclaimer in the documentation
00018  *    and/or other materials provided with the distribution.
00019  * 3. The name of the author may not be used to endorse or promote products
00020  *    derived from this software without specific prior written permission.
00021  *
00022  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00023  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00024  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00025  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00026  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00027  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00029  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00030  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00031  * OF SUCH DAMAGE.
00032  *
00033  * This file is part of the lwIP TCP/IP stack.
00034  *
00035  * Author: Adam Dunkels <adam@sics.se>
00036  *
00037  */
00038 
00039 /*
00040  * This file is a skeleton for developing Ethernet network interface
00041  * drivers for lwIP. Add code to the low_level functions and do a
00042  * search-and-replace for the word "ethernetif" to replace it with
00043  * something that better describes your network interface.
00044  */
00045 
00046 #include "lwip/opt.h"
00047 
00048 #if 0 /* don't build, this is only a skeleton, see previous comment */
00049 
00050 #include "lwip/def.h"
00051 #include "lwip/mem.h"
00052 #include "lwip/pbuf.h"
00053 #include "lwip/stats.h"
00054 #include "lwip/snmp.h"
00055 #include "lwip/ethip6.h"
00056 #include "lwip/etharp.h"
00057 #include "netif/ppp/pppoe.h"
00058 
00059 /* Define those to better describe your network interface. */
00060 #define IFNAME0 'e'
00061 #define IFNAME1 'n'
00062 
00063 /**
00064  * Helper struct to hold private data used to operate your ethernet interface.
00065  * Keeping the ethernet address of the MAC in this struct is not necessary
00066  * as it is already kept in the struct netif.
00067  * But this is only an example, anyway...
00068  */
00069 struct ethernetif {
00070   struct eth_addr *ethaddr;
00071   /* Add whatever per-interface state that is needed here. */
00072 };
00073 
00074 /* Forward declarations. */
00075 static void  ethernetif_input(struct netif *netif);
00076 
00077 /**
00078  * In this function, the hardware should be initialized.
00079  * Called from ethernetif_init().
00080  *
00081  * @param netif the already initialized lwip network interface structure
00082  *        for this ethernetif
00083  */
00084 static void
00085 low_level_init(struct netif *netif)
00086 {
00087   struct ethernetif *ethernetif = netif->state;
00088 
00089   /* set MAC hardware address length */
00090   netif->hwaddr_len = ETHARP_HWADDR_LEN;
00091 
00092   /* set MAC hardware address */
00093   netif->hwaddr[0] = ;
00094   ...
00095   netif->hwaddr[5] = ;
00096 
00097   /* maximum transfer unit */
00098   netif->mtu = 1500;
00099 
00100   /* device capabilities */
00101   /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
00102   netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;
00103 
00104 #if LWIP_IPV6 && LWIP_IPV6_MLD
00105   /*
00106    * For hardware/netifs that implement MAC filtering.
00107    * All-nodes link-local is handled by default, so we must let the hardware know
00108    * to allow multicast packets in.
00109    * Should set mld_mac_filter previously. */
00110   if (netif->mld_mac_filter != NULL) {
00111     ip6_addr_t ip6_allnodes_ll;
00112     ip6_addr_set_allnodes_linklocal(&ip6_allnodes_ll);
00113     netif->mld_mac_filter(netif, &ip6_allnodes_ll, NETIF_ADD_MAC_FILTER);
00114   }
00115 #endif /* LWIP_IPV6 && LWIP_IPV6_MLD */
00116 
00117   /* Do whatever else is needed to initialize interface. */
00118 }
00119 
00120 /**
00121  * This function should do the actual transmission of the packet. The packet is
00122  * contained in the pbuf that is passed to the function. This pbuf
00123  * might be chained.
00124  *
00125  * @param netif the lwip network interface structure for this ethernetif
00126  * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
00127  * @return ERR_OK if the packet could be sent
00128  *         an err_t value if the packet couldn't be sent
00129  *
00130  * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
00131  *       strange results. You might consider waiting for space in the DMA queue
00132  *       to become available since the stack doesn't retry to send a packet
00133  *       dropped because of memory failure (except for the TCP timers).
00134  */
00135 
00136 static err_t
00137 low_level_output(struct netif *netif, struct pbuf *p)
00138 {
00139   struct ethernetif *ethernetif = netif->state;
00140   struct pbuf *q;
00141 
00142   initiate transfer();
00143 
00144 #if ETH_PAD_SIZE
00145   pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
00146 #endif
00147 
00148   for (q = p; q != NULL; q = q->next) {
00149     /* Send the data from the pbuf to the interface, one pbuf at a
00150        time. The size of the data in each pbuf is kept in the ->len
00151        variable. */
00152     send data from(q->payload, q->len);
00153   }
00154 
00155   signal that packet should be sent();
00156 
00157   MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p->tot_len);
00158   if (((u8_t*)p->payload)[0] & 1) {
00159     /* broadcast or multicast packet*/
00160     MIB2_STATS_NETIF_INC(netif, ifoutnucastpkts);
00161   } else {
00162     /* unicast packet */
00163     MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
00164   }
00165   /* increase ifoutdiscards or ifouterrors on error */
00166 
00167 #if ETH_PAD_SIZE
00168   pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
00169 #endif
00170 
00171   LINK_STATS_INC(link.xmit);
00172 
00173   return ERR_OK;
00174 }
00175 
00176 /**
00177  * Should allocate a pbuf and transfer the bytes of the incoming
00178  * packet from the interface into the pbuf.
00179  *
00180  * @param netif the lwip network interface structure for this ethernetif
00181  * @return a pbuf filled with the received packet (including MAC header)
00182  *         NULL on memory error
00183  */
00184 static struct pbuf *
00185 low_level_input(struct netif *netif)
00186 {
00187   struct ethernetif *ethernetif = netif->state;
00188   struct pbuf *p, *q;
00189   u16_t len;
00190 
00191   /* Obtain the size of the packet and put it into the "len"
00192      variable. */
00193   len = ;
00194 
00195 #if ETH_PAD_SIZE
00196   len += ETH_PAD_SIZE; /* allow room for Ethernet padding */
00197 #endif
00198 
00199   /* We allocate a pbuf chain of pbufs from the pool. */
00200   p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
00201 
00202   if (p != NULL) {
00203 
00204 #if ETH_PAD_SIZE
00205     pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
00206 #endif
00207 
00208     /* We iterate over the pbuf chain until we have read the entire
00209      * packet into the pbuf. */
00210     for (q = p; q != NULL; q = q->next) {
00211       /* Read enough bytes to fill this pbuf in the chain. The
00212        * available data in the pbuf is given by the q->len
00213        * variable.
00214        * This does not necessarily have to be a memcpy, you can also preallocate
00215        * pbufs for a DMA-enabled MAC and after receiving truncate it to the
00216        * actually received size. In this case, ensure the tot_len member of the
00217        * pbuf is the sum of the chained pbuf len members.
00218        */
00219       read data into(q->payload, q->len);
00220     }
00221     acknowledge that packet has been read();
00222 
00223     MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
00224     if (((u8_t*)p->payload)[0] & 1) {
00225       /* broadcast or multicast packet*/
00226       MIB2_STATS_NETIF_INC(netif, ifinnucastpkts);
00227     } else {
00228       /* unicast packet*/
00229       MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
00230     }
00231 #if ETH_PAD_SIZE
00232     pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
00233 #endif
00234 
00235     LINK_STATS_INC(link.recv);
00236   } else {
00237     drop packet();
00238     LINK_STATS_INC(link.memerr);
00239     LINK_STATS_INC(link.drop);
00240     MIB2_STATS_NETIF_INC(netif, ifindiscards);
00241   }
00242 
00243   return p;
00244 }
00245 
00246 /**
00247  * This function should be called when a packet is ready to be read
00248  * from the interface. It uses the function low_level_input() that
00249  * should handle the actual reception of bytes from the network
00250  * interface. Then the type of the received packet is determined and
00251  * the appropriate input function is called.
00252  *
00253  * @param netif the lwip network interface structure for this ethernetif
00254  */
00255 static void
00256 ethernetif_input(struct netif *netif)
00257 {
00258   struct ethernetif *ethernetif;
00259   struct eth_hdr *ethhdr;
00260   struct pbuf *p;
00261 
00262   ethernetif = netif->state;
00263 
00264   /* move received packet into a new pbuf */
00265   p = low_level_input(netif);
00266   /* if no packet could be read, silently ignore this */
00267   if (p != NULL) {
00268     /* pass all packets to ethernet_input, which decides what packets it supports */
00269     if (netif->input(p, netif) != ERR_OK) {
00270       LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
00271       pbuf_free(p);
00272       p = NULL;
00273     }
00274   }
00275 }
00276 
00277 /**
00278  * Should be called at the beginning of the program to set up the
00279  * network interface. It calls the function low_level_init() to do the
00280  * actual setup of the hardware.
00281  *
00282  * This function should be passed as a parameter to netif_add().
00283  *
00284  * @param netif the lwip network interface structure for this ethernetif
00285  * @return ERR_OK if the loopif is initialized
00286  *         ERR_MEM if private data couldn't be allocated
00287  *         any other err_t on error
00288  */
00289 err_t
00290 ethernetif_init(struct netif *netif)
00291 {
00292   struct ethernetif *ethernetif;
00293 
00294   LWIP_ASSERT("netif != NULL", (netif != NULL));
00295 
00296   ethernetif = mem_malloc(sizeof(struct ethernetif));
00297   if (ethernetif == NULL) {
00298     LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));
00299     return ERR_MEM;
00300   }
00301 
00302 #if LWIP_NETIF_HOSTNAME
00303   /* Initialize interface hostname */
00304   netif->hostname = "lwip";
00305 #endif /* LWIP_NETIF_HOSTNAME */
00306 
00307   /*
00308    * Initialize the snmp variables and counters inside the struct netif.
00309    * The last argument should be replaced with your link speed, in units
00310    * of bits per second.
00311    */
00312   MIB2_INIT_NETIF(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED_OF_YOUR_NETIF_IN_BPS);
00313 
00314   netif->state = ethernetif;
00315   netif->name[0] = IFNAME0;
00316   netif->name[1] = IFNAME1;
00317   /* We directly use etharp_output() here to save a function call.
00318    * You can instead declare your own function an call etharp_output()
00319    * from it if you have to do some checks before sending (e.g. if link
00320    * is available...) */
00321   netif->output = etharp_output;
00322 #if LWIP_IPV6
00323   netif->output_ip6 = ethip6_output;
00324 #endif /* LWIP_IPV6 */
00325   netif->linkoutput = low_level_output;
00326 
00327   ethernetif->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);
00328 
00329   /* initialize the hardware */
00330   low_level_init(netif);
00331 
00332   return ERR_OK;
00333 }
00334 
00335 #endif /* 0 */