lwip_ethip6.c

00001 /**
00002  * @file
00003  *
00004  * Ethernet output for IPv6. Uses ND tables for link-layer addressing.
00005  */
00006 
00007 /*
00008  * Copyright (c) 2010 Inico Technologies Ltd.
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: Ivan Delamer <delamer@inicotech.com>
00036  *
00037  *
00038  * Please coordinate changes and requests with Ivan Delamer
00039  * <delamer@inicotech.com>
00040  */
00041 
00042 #include "lwip/opt.h"
00043 
00044 #if LWIP_IPV6 && LWIP_ETHERNET
00045 
00046 #include "lwip/ethip6.h"
00047 #include "lwip/nd6.h"
00048 #include "lwip/pbuf.h"
00049 #include "lwip/ip6.h"
00050 #include "lwip/ip6_addr.h"
00051 #include "lwip/inet_chksum.h"
00052 #include "lwip/netif.h"
00053 #include "lwip/icmp6.h"
00054 #include "netif/lwip_ethernet.h"
00055 
00056 #include <string.h>
00057 
00058 /**
00059  * Send an IPv6 packet on the network using netif->linkoutput
00060  * The ethernet header is filled in before sending.
00061  *
00062  * @params netif the lwIP network interface on which to send the packet
00063  * @params p the packet to send, p->payload pointing to the (uninitialized) ethernet header
00064  * @params src the source MAC address to be copied into the ethernet header
00065  * @params dst the destination MAC address to be copied into the ethernet header
00066  * @return ERR_OK if the packet was sent, any other err_t on failure
00067  */
00068 static err_t
00069 ethip6_send(struct netif *netif, struct pbuf *p, struct eth_addr *src, struct eth_addr *dst)
00070 {
00071   struct eth_hdr *ethhdr = (struct eth_hdr *)p->payload;
00072 
00073   LWIP_ASSERT("netif->hwaddr_len must be 6 for ethip6!",
00074               (netif->hwaddr_len == 6));
00075   SMEMCPY(&ethhdr->dest, dst, 6);
00076   SMEMCPY(&ethhdr->src, src, 6);
00077   ethhdr->type = PP_HTONS(ETHTYPE_IPV6);
00078   LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("ethip6_send: sending packet %p\n", (void *)p));
00079   /* send the packet */
00080   return netif->linkoutput(netif, p);
00081 }
00082 
00083 /**
00084  * Resolve and fill-in Ethernet address header for outgoing IPv6 packet.
00085  *
00086  * For IPv6 multicast, corresponding Ethernet addresses
00087  * are selected and the packet is transmitted on the link.
00088  *
00089  * For unicast addresses, ...
00090  *
00091  * @todo anycast addresses
00092  *
00093  * @param netif The lwIP network interface which the IP packet will be sent on.
00094  * @param q The pbuf(s) containing the IP packet to be sent.
00095  * @param ip6addr The IP address of the packet destination.
00096  *
00097  * @return
00098  * - ERR_RTE No route to destination (no gateway to external networks),
00099  * or the return type of either etharp_query() or etharp_send_ip().
00100  */
00101 err_t
00102 ethip6_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
00103 {
00104   struct eth_addr dest;
00105   s8_t i;
00106 
00107   /* make room for Ethernet header - should not fail */
00108   if (pbuf_header(q, sizeof(struct eth_hdr)) != 0) {
00109     /* bail out */
00110     LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
00111       ("etharp_output: could not allocate room for header.\n"));
00112     return ERR_BUF;
00113   }
00114 
00115   /* multicast destination IP address? */
00116   if (ip6_addr_ismulticast(ip6addr)) {
00117     /* Hash IP multicast address to MAC address.*/
00118     dest.addr[0] = 0x33;
00119     dest.addr[1] = 0x33;
00120     dest.addr[2] = ((const u8_t *)(&(ip6addr->addr[3])))[0];
00121     dest.addr[3] = ((const u8_t *)(&(ip6addr->addr[3])))[1];
00122     dest.addr[4] = ((const u8_t *)(&(ip6addr->addr[3])))[2];
00123     dest.addr[5] = ((const u8_t *)(&(ip6addr->addr[3])))[3];
00124 
00125     /* Send out. */
00126     return ethip6_send(netif, q, (struct eth_addr*)(netif->hwaddr), &dest);
00127   }
00128 
00129   /* We have a unicast destination IP address */
00130   /* @todo anycast? */
00131   /* Get next hop record. */
00132   i = nd6_get_next_hop_entry(ip6addr, netif);
00133   if (i < 0) {
00134     /* failed to get a next hop neighbor record. */
00135     return ERR_MEM;
00136   }
00137 
00138   /* Now that we have a destination record, send or queue the packet. */
00139   if (neighbor_cache[i].state == ND6_STALE) {
00140     /* Switch to delay state. */
00141     neighbor_cache[i].state = ND6_DELAY;
00142     neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME;
00143   }
00144   /* @todo should we send or queue if PROBE? send for now, to let unicast NS pass. */
00145   if ((neighbor_cache[i].state == ND6_REACHABLE) ||
00146       (neighbor_cache[i].state == ND6_DELAY) ||
00147       (neighbor_cache[i].state == ND6_PROBE)) {
00148 
00149     /* Send out. */
00150     SMEMCPY(dest.addr, neighbor_cache[i].lladdr, 6);
00151     return ethip6_send(netif, q, (struct eth_addr*)(netif->hwaddr), &dest);
00152   }
00153 
00154   /* We should queue packet on this interface. */
00155   pbuf_header(q, -(s16_t)SIZEOF_ETH_HDR);
00156   return nd6_queue_packet(i, q);
00157 }
00158 
00159 #endif /* LWIP_IPV6 && LWIP_ETHERNET */