/****************************************************************************
* net/neighbor/neighbor_out.c
*
* Copyright (C) 2015 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <string.h>
#include <debug.h>
#include <nuttx/net/arp.h>
#include <nuttx/net/netdev.h>
#include "route/route.h"
#include "icmpv6/icmpv6.h"
#include "neighbor/neighbor.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define ETHBUF ((struct eth_hdr_s *)dev->d_buf)
#define IPv6BUF ((struct ipv6_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)])
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/* Support for broadcast address */
static const struct ether_addr g_broadcast_ethaddr =
{
{
0xff, 0xff, 0xff, 0xff, 0xff, 0xff
}
};
/* Support for IGMP multicast addresses.
*
* Well-known ethernet multicast address:
*
* ADDRESS TYPE USAGE
* 01-00-0c-cc-cc-cc 0x0802 CDP (Cisco Discovery Protocol), VTP (Virtual Trunking Protocol)
* 01-00-0c-cc-cc-cd 0x0802 Cisco Shared Spanning Tree Protocol Address
* 01-80-c2-00-00-00 0x0802 Spanning Tree Protocol (for bridges) IEEE 802.1D
* 01-80-c2-00-00-02 0x0809 Ethernet OAM Protocol IEEE 802.3ah
* 01-00-5e-xx-xx-xx 0x0800 IPv4 IGMP Multicast Address
* 33-33-00-00-00-00 0x86DD IPv6 Neighbor Discovery
* 33-33-xx-xx-xx-xx 0x86DD IPv6 Multicast Address (RFC3307)
*
* The following is the first three octects of the IGMP address:
*/
#ifdef CONFIG_NET_IGMP
static const uint8_t g_multicast_ethaddr[3] =
{
0x01, 0x00, 0x5e
};
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: neighbor_out
*
* Description:
* This function should be called before sending out an IPv6 packet. The
* function checks the destination IPv6 address of the IPv6 packet to see
* what Ethernet MAC address that should be used as a destination MAC
* address on the Ethernet.
*
* If the destination IPv6 address is in the local network (determined
* by logical ANDing of netmask and our IPv6 address), the function
* checks the Neighbor Table to see if an entry for the destination IPv6
* address is found. If so, an Ethernet header is pre-pended at the
* beginning of the packet and the function returns.
*
* If no Neighbor Table entry is found for the destination IPv6 address,
* the packet in the d_buf[] is replaced by an ICMPv6 Neighbor Solicit
* request packet for the IPv6 address. The IPv6 packet is dropped and
* it is assumed that the higher level protocols (e.g., TCP) eventually
* will retransmit the dropped packet.
*
* Upon return in either the case, a packet to be sent is present in the
* d_buf[] buffer and the d_len field holds the length of the Ethernet
* frame that should be transmitted.
*
****************************************************************************/
void neighbor_out(FAR struct net_driver_s *dev)
{
FAR const struct neighbor_addr_s *naddr;
FAR struct eth_hdr_s *eth = ETHBUF;
FAR struct ipv6_hdr_s *ip = IPv6BUF;
net_ipv6addr_t ipaddr;
/* Skip sending Neighbor Solicitations when the frame to be transmitted was
* written into a packet socket or if we are sending certain Neighbor
* messages (solicitation, advertisement, echo request).
*/
if (IFF_IS_NOARP(dev->d_flags))
{
/* Clear the indication and let the packet continue on its way. */
IFF_CLR_NOARP(dev->d_flags);
return;
}
/* Find the destination IPv6 address in the Neighbor Table and construct
* the Ethernet header. If the destination IPv6 address isn't on the local
* network, we use the default router's IPv6 address instead.
*
* If no Neighbor Table entry is found, we overwrite the original IPv6
* packet with an Neighbor Solicitation Request for the IPv6 address.
*/
/* First check if destination is a IPv6 multicast address. IPv6
* multicast addresses in IPv6 have the prefix ff00::/8
*
* Bits 120-127: Prefix
* Bits 116-119: Flags (1, 2, or 3 defined)
* Bits 112-115: Scope
*
* REVISIT: Need to revisit IPv6 broadcast support. Broadcast
* IP addresses are not used with IPv6; multicast is used instead.
* Does this mean that all multicast address should go to the
* broadcast Ethernet address?
*/
if ((ip->destipaddr[0] & HTONS(0xff00)) == HTONS(0xff00))
{
memcpy(eth->dest, g_broadcast_ethaddr.ether_addr_octet,
ETHER_ADDR_LEN);
}
#ifdef CONFIG_NET_IGMP
/* Check if the destination address is a multicast address
*
* IPv6 multicast addresses are have the high-order octet of the
* addresses=0xff (ff00::/8.)
*
* REVISIT: See comments above. How do we distinguish broadcast
* from IGMP multicast?
*/
#warning Missing logic
#endif
else
{
/* Check if the destination address is on the local network. */
if (!net_ipv6addr_maskcmp(ip->destipaddr, dev->d_ipv6addr,
dev->d_ipv6netmask))
{
/* Destination address is not on the local network */
#ifdef CONFIG_NET_ROUTE
/* We have a routing table.. find the correct router to use in
* this case (or, as a fall-back, use the device's default router
* address). We will use the router IPv6 address instead of the
* destination address when determining the MAC address.
*/
netdev_ipv6_router(dev, ip->destipaddr, ipaddr);
#else
/* Use the device's default router IPv6 address instead of the
* destination address when determining the MAC address.
*/
net_ipv6addr_copy(ipaddr, dev->d_ipv6draddr);
#endif
}
else
{
/* Else, we use the destination IPv6 address. */
net_ipv6addr_copy(ipaddr, ip->destipaddr);
}
/* Check if we already have this destination address in the Neighbor Table */
naddr = neighbor_lookup(ipaddr);
if (!naddr)
{
ninfo("IPv6 Neighbor solicitation for IPv6\n");
/* The destination address was not in our Neighbor Table, so we
* overwrite the IPv6 packet with an ICMDv6 Neighbor Solicitation
* message.
*/
icmpv6_solicit(dev, ipaddr);
return;
}
/* Build an Ethernet header. */
memcpy(eth->dest, naddr->na_addr.ether_addr_octet, ETHER_ADDR_LEN);
}
/* Finish populating the Ethernet header */
memcpy(eth->src, dev->d_mac.ether_addr_octet, ETHER_ADDR_LEN);
eth->type = HTONS(ETHTYPE_IP6);
/* Add the size of the layer layer header to the total size of the
* outgoing packet.
*/
dev->d_len += netdev_ipv6_hdrlen(dev);
ninfo("Outgoing IPv6 Packet length: %d (%d)\n",
dev->d_len, (ip->len[0] << 8) | ip->len[1]);
}