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 */
69struct ethernetif {
70  struct eth_addr *ethaddr;
71  /* Add whatever per-interface state that is needed here. */
72};
73
74/* Forward declarations. */
75static 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 */
84static void
85low_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
123static err_t
124low_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 */
161static struct pbuf *
162low_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 */
223static void
224ethernetif_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 */
275err_t
276ethernetif_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 */
319