3 * Ethernet Interface Skeleton
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33 * This file is part of the lwIP TCP/IP stack.
35 * Author: Adam Dunkels <adam@sics.se>
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.
49 #include "lwip/pbuf.h"
51 #include <lwip/stats.h>
53 #include "netif/etharp.h"
54 #include "netif/ppp_oe.h"
56 /* Define those to better describe your network interface. */
61 * Helper struct to hold private data used to operate your ethernet interface.
62 * Keeping the ethernet address of the MAC in this struct is not necessary
63 * as it is already kept in the struct netif.
64 * But this is only an example, anyway...
67 struct eth_addr *ethaddr;
68 /* Add whatever per-interface state that is needed here. */
71 /* Forward declarations. */
72 static void ethernetif_input(struct netif *netif);
75 * In this function, the hardware should be initialized.
76 * Called from ethernetif_init().
78 * @param netif the already initialized lwip network interface structure
82 low_level_init(struct netif *netif)
84 struct ethernetif *ethernetif = netif->state;
86 /* set MAC hardware address length */
87 netif->hwaddr_len = 6;
89 /* set MAC hardware address */
94 /* maximum transfer unit */
97 /* device capabilities */
98 /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
99 netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;
101 /* Do whatever else is needed to initialize interface. */
105 * This function should do the actual transmission of the packet. The packet is
106 * contained in the pbuf that is passed to the function. This pbuf
109 * @param netif the lwip network interface structure for this ethernetif
110 * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
111 * @return ERR_OK if the packet could be sent
112 * an err_t value if the packet couldn't be sent
114 * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
115 * strange results. You might consider waiting for space in the DMA queue
116 * to become availale since the stack doesn't retry to send a packet
117 * dropped because of memory failure (except for the TCP timers).
121 low_level_output(struct netif *netif, struct pbuf *p)
123 struct ethernetif *ethernetif = netif->state;
129 pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
132 for(q = p; q != NULL; q = q->next) {
133 /* Send the data from the pbuf to the interface, one pbuf at a
134 time. The size of the data in each pbuf is kept in the ->len
136 send data from(q->payload, q->len);
139 signal that packet should be sent();
142 pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
146 lwip_stats.link.xmit++;
147 #endif /* LINK_STATS */
153 * Should allocate a pbuf and transfer the bytes of the incoming
154 * packet from the interface into the pbuf.
156 * @param netif the lwip network interface structure for this ethernetif
157 * @return a pbuf filled with the received packet (including MAC header)
158 * NULL on memory error
161 low_level_input(struct netif *netif)
163 struct ethernetif *ethernetif = netif->state;
167 /* Obtain the size of the packet and put it into the "len"
172 len += ETH_PAD_SIZE; /* allow room for Ethernet padding */
175 /* We allocate a pbuf chain of pbufs from the pool. */
176 p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
181 pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
184 /* We iterate over the pbuf chain until we have read the entire
185 * packet into the pbuf. */
186 for(q = p; q != NULL; q = q->next) {
187 /* Read enough bytes to fill this pbuf in the chain. The
188 * available data in the pbuf is given by the q->len
190 read data into(q->payload, q->len);
192 acknowledge that packet has been read();
195 pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
199 lwip_stats.link.recv++;
200 #endif /* LINK_STATS */
204 lwip_stats.link.memerr++;
205 lwip_stats.link.drop++;
206 #endif /* LINK_STATS */
213 * This function should be called when a packet is ready to be read
214 * from the interface. It uses the function low_level_input() that
215 * should handle the actual reception of bytes from the network
216 * interface. Then the type of the received packet is determined and
217 * the appropriate input function is called.
219 * @param netif the lwip network interface structure for this ethernetif
222 ethernetif_input(struct netif *netif)
224 struct ethernetif *ethernetif;
225 struct eth_hdr *ethhdr;
228 ethernetif = netif->state;
230 /* move received packet into a new pbuf */
231 p = low_level_input(netif);
232 /* no packet could be read, silently ignore this */
233 if (p == NULL) return;
234 /* points to packet payload, which starts with an Ethernet header */
237 switch (htons(ethhdr->type)) {
238 /* IP or ARP packet? */
243 case ETHTYPE_PPPOEDISC:
245 #endif /* PPPOE_SUPPORT */
246 /* full packet send to tcpip_thread to process */
247 if (netif->input(p, netif)!=ERR_OK)
248 { LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
262 * Should be called at the beginning of the program to set up the
263 * network interface. It calls the function low_level_init() to do the
264 * actual setup of the hardware.
266 * This function should be passed as a parameter to netif_add().
268 * @param netif the lwip network interface structure for this ethernetif
269 * @return ERR_OK if the loopif is initialized
270 * ERR_MEM if private data couldn't be allocated
271 * any other err_t on error
274 ethernetif_init(struct netif *netif)
276 struct ethernetif *ethernetif;
278 LWIP_ASSERT("netif != NULL", (netif != NULL));
280 ethernetif = mem_malloc(sizeof(struct ethernetif));
281 if (ethernetif == NULL) {
282 LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));
286 #if LWIP_NETIF_HOSTNAME
287 /* Initialize interface hostname */
288 netif->hostname = "lwip";
289 #endif /* LWIP_NETIF_HOSTNAME */
291 /* initialize the snmp variables and counters inside the struct netif */
292 /* ifType ethernetCsmacd(6) @see RFC1213 */
293 NETIF_INIT_SNMP(netif, 6, ???);
295 netif->state = ethernetif;
296 netif->name[0] = IFNAME0;
297 netif->name[1] = IFNAME1;
298 /* We directly use etharp_output() here to save a function call.
299 * You can instead declare your own function an call etharp_output()
300 * from it if you have to do some checks before sending (e.g. if link
301 * is available...) */
302 netif->output = etharp_output;
303 netif->linkoutput = low_level_output;
305 ethernetif->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);
307 /* initialize the hardware */
308 low_level_init(netif);