Diff: netif/ethernetif.c

Revision:

0:51ac1d130fd4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netif/ethernetif.c	Fri Jun 22 09:25:39 2012 +0000
@@ -0,0 +1,318 @@
+/**
+ * @file
+ * Ethernet Interface Skeleton
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/*
+ * This file is a skeleton for developing Ethernet network interface
+ * drivers for lwIP. Add code to the low_level functions and do a
+ * search-and-replace for the word "ethernetif" to replace it with
+ * something that better describes your network interface.
+ */
+
+#include "lwip/opt.h"
+
+#if 0 /* don't build, this is only a skeleton, see previous comment */
+
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/sys.h"
+#include <lwip/stats.h>
+#include <lwip/snmp.h>
+#include "netif/etharp.h"
+#include "netif/ppp_oe.h"
+
+/* Define those to better describe your network interface. */
+#define IFNAME0 'e'
+#define IFNAME1 'n'
+
+/**
+ * Helper struct to hold private data used to operate your ethernet interface.
+ * Keeping the ethernet address of the MAC in this struct is not necessary
+ * as it is already kept in the struct netif.
+ * But this is only an example, anyway...
+ */
+struct ethernetif {
+  struct eth_addr *ethaddr;
+  /* Add whatever per-interface state that is needed here. */
+};
+
+/* Forward declarations. */
+static void  ethernetif_input(struct netif *netif);
+
+/**
+ * In this function, the hardware should be initialized.
+ * Called from ethernetif_init().
+ *
+ * @param netif the already initialized lwip network interface structure
+ *        for this ethernetif
+ */
+static void
+low_level_init(struct netif *netif)
+{
+  struct ethernetif *ethernetif = netif->state;
+  
+  /* set MAC hardware address length */
+  netif->hwaddr_len = ETHARP_HWADDR_LEN;
+
+  /* set MAC hardware address */
+  netif->hwaddr[0] = ;
+  ...
+  netif->hwaddr[5] = ;
+
+  /* maximum transfer unit */
+  netif->mtu = 1500;
+  
+  /* device capabilities */
+  /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
+  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;
+ 
+  /* Do whatever else is needed to initialize interface. */  
+}
+
+/**
+ * This function should do the actual transmission of the packet. The packet is
+ * contained in the pbuf that is passed to the function. This pbuf
+ * might be chained.
+ *
+ * @param netif the lwip network interface structure for this ethernetif
+ * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
+ * @return ERR_OK if the packet could be sent
+ *         an err_t value if the packet couldn't be sent
+ *
+ * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
+ *       strange results. You might consider waiting for space in the DMA queue
+ *       to become availale since the stack doesn't retry to send a packet
+ *       dropped because of memory failure (except for the TCP timers).
+ */
+
+static err_t
+low_level_output(struct netif *netif, struct pbuf *p)
+{
+  struct ethernetif *ethernetif = netif->state;
+  struct pbuf *q;
+
+  initiate transfer();
+  
+#if ETH_PAD_SIZE
+  pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
+#endif
+
+  for(q = p; q != NULL; q = q->next) {
+    /* Send the data from the pbuf to the interface, one pbuf at a
+       time. The size of the data in each pbuf is kept in the ->len
+       variable. */
+    send data from(q->payload, q->len);
+  }
+
+  signal that packet should be sent();
+
+#if ETH_PAD_SIZE
+  pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
+#endif
+  
+  LINK_STATS_INC(link.xmit);
+
+  return ERR_OK;
+}
+
+/**
+ * Should allocate a pbuf and transfer the bytes of the incoming
+ * packet from the interface into the pbuf.
+ *
+ * @param netif the lwip network interface structure for this ethernetif
+ * @return a pbuf filled with the received packet (including MAC header)
+ *         NULL on memory error
+ */
+static struct pbuf *
+low_level_input(struct netif *netif)
+{
+  struct ethernetif *ethernetif = netif->state;
+  struct pbuf *p, *q;
+  u16_t len;
+
+  /* Obtain the size of the packet and put it into the "len"
+     variable. */
+  len = ;
+
+#if ETH_PAD_SIZE
+  len += ETH_PAD_SIZE; /* allow room for Ethernet padding */
+#endif
+
+  /* We allocate a pbuf chain of pbufs from the pool. */
+  p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
+  
+  if (p != NULL) {
+
+#if ETH_PAD_SIZE
+    pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
+#endif
+
+    /* We iterate over the pbuf chain until we have read the entire
+     * packet into the pbuf. */
+    for(q = p; q != NULL; q = q->next) {
+      /* Read enough bytes to fill this pbuf in the chain. The
+       * available data in the pbuf is given by the q->len
+       * variable.
+       * This does not necessarily have to be a memcpy, you can also preallocate
+       * pbufs for a DMA-enabled MAC and after receiving truncate it to the
+       * actually received size. In this case, ensure the tot_len member of the
+       * pbuf is the sum of the chained pbuf len members.
+       */
+      read data into(q->payload, q->len);
+    }
+    acknowledge that packet has been read();
+
+#if ETH_PAD_SIZE
+    pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
+#endif
+
+    LINK_STATS_INC(link.recv);
+  } else {
+    drop packet();
+    LINK_STATS_INC(link.memerr);
+    LINK_STATS_INC(link.drop);
+  }
+
+  return p;  
+}
+
+/**
+ * This function should be called when a packet is ready to be read
+ * from the interface. It uses the function low_level_input() that
+ * should handle the actual reception of bytes from the network
+ * interface. Then the type of the received packet is determined and
+ * the appropriate input function is called.
+ *
+ * @param netif the lwip network interface structure for this ethernetif
+ */
+static void
+ethernetif_input(struct netif *netif)
+{
+  struct ethernetif *ethernetif;
+  struct eth_hdr *ethhdr;
+  struct pbuf *p;
+
+  ethernetif = netif->state;
+
+  /* move received packet into a new pbuf */
+  p = low_level_input(netif);
+  /* no packet could be read, silently ignore this */
+  if (p == NULL) return;
+  /* points to packet payload, which starts with an Ethernet header */
+  ethhdr = p->payload;
+
+  switch (htons(ethhdr->type)) {
+  /* IP or ARP packet? */
+  case ETHTYPE_IP:
+  case ETHTYPE_ARP:
+#if PPPOE_SUPPORT
+  /* PPPoE packet? */
+  case ETHTYPE_PPPOEDISC:
+  case ETHTYPE_PPPOE:
+#endif /* PPPOE_SUPPORT */
+    /* full packet send to tcpip_thread to process */
+    if (netif->input(p, netif)!=ERR_OK)
+     { LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
+       pbuf_free(p);
+       p = NULL;
+     }
+    break;
+
+  default:
+    pbuf_free(p);
+    p = NULL;
+    break;
+  }
+}
+
+/**
+ * Should be called at the beginning of the program to set up the
+ * network interface. It calls the function low_level_init() to do the
+ * actual setup of the hardware.
+ *
+ * This function should be passed as a parameter to netif_add().
+ *
+ * @param netif the lwip network interface structure for this ethernetif
+ * @return ERR_OK if the loopif is initialized
+ *         ERR_MEM if private data couldn't be allocated
+ *         any other err_t on error
+ */
+err_t
+ethernetif_init(struct netif *netif)
+{
+  struct ethernetif *ethernetif;
+
+  LWIP_ASSERT("netif != NULL", (netif != NULL));
+    
+  ethernetif = mem_malloc(sizeof(struct ethernetif));
+  if (ethernetif == NULL) {
+    LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));
+    return ERR_MEM;
+  }
+
+#if LWIP_NETIF_HOSTNAME
+  /* Initialize interface hostname */
+  netif->hostname = "lwip";
+#endif /* LWIP_NETIF_HOSTNAME */
+
+  /*
+   * Initialize the snmp variables and counters inside the struct netif.
+   * The last argument should be replaced with your link speed, in units
+   * of bits per second.
+   */
+  NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED_OF_YOUR_NETIF_IN_BPS);
+
+  netif->state = ethernetif;
+  netif->name[0] = IFNAME0;
+  netif->name[1] = IFNAME1;
+  /* We directly use etharp_output() here to save a function call.
+   * You can instead declare your own function an call etharp_output()
+   * from it if you have to do some checks before sending (e.g. if link
+   * is available...) */
+  netif->output = etharp_output;
+  netif->linkoutput = low_level_output;
+  
+  ethernetif->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);
+  
+  /* initialize the hardware */
+  low_level_init(netif);
+
+  return ERR_OK;
+}
+
+#endif /* 0 */