495 lines
15 KiB
C
495 lines
15 KiB
C
/****************************************************************************
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* net/devif/ipv6_forward.c
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*
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* Copyright (C) 2017 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <debug.h>
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#include <errno.h>
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#include <nuttx/net/net.h>
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#include <nuttx/net/netdev.h>
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#include <nuttx/net/netstats.h>
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#include "netdev/netdev.h"
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#include "sixlowpan/sixlowpan.h"
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#include "devif/devif.h"
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#if defined(CONFIG_NET_IPFORWARD) && defined(CONFIG_NET_IPv6)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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#if defined(CONFIG_NET_UDP) || defined(CONFIG_NET_ICMPv6)
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/* IPv6 + UDP or ICMPv6 header */
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struct ipv6l3_hdr_s
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{
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struct ipv6_hdr_s ipv6;
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union
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{
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#ifdef CONFIG_NET_UDP
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struct udp_hdr_s udp;
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#ifdef CONFIG_NET_ICMPv6
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struct icmpv6_iphdr_s icmp;
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} u;
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};
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#endif
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/* This is the send state structure */
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struct forward_s
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{
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FAR net_driver_s *dev; /* Forwarding device */
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struct ipv6l3_hdr_s hdr; /* Copy of origin L2+L3 headers */
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FAR struct iob_queue_s iobq; /* IOBs contained the data payload */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: ipv6_packet_conversion
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*
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* Description:
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* Generic output conversion hook. Only needed for IEEE802.15.4 for now
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* but this is a point where support for other conversions may be
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* provided.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_6LOWPAN
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static int ipv6_packet_conversion(FAR struct net_driver_s *dev,
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FAR struct net_driver_s *fwddev,
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FAR struct ipv6_hdr_s *ipv6)
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{
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#ifdef CONFIG_NET_MULTILINK
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/* Handle the case where multiple link layer protocols are supported */
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if (dev->d_len > 0 && fwddev->d_lltype == NET_LL_IEEE802154)
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#else
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if (dev->d_len > 0)
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#endif
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{
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#ifdef CONFIG_NET_TCP
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if (ipv6->proto == IP_PROTO_TCP)
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{
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/* Let 6LoWPAN convert IPv6 TCP output into IEEE802.15.4 frames. */
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sixlowpan_tcp_send(dev, fwddev, ipv6);
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}
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else
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#endif
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#ifdef CONFIG_NET_UDP
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if (ipv6->proto == IP_PROTO_UDP)
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{
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/* Let 6LoWPAN convert IPv6 UDP output into IEEE802.15.4 frames. */
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sixlowpan_udp_send(dev, fwddev, ipv6);
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}
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else
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#endif
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{
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/* Otherwise, we will have to drop the packet */
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nwarn("WARNING: Dropping. Unsupported 6LoWPAN protocol: %d\n",
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ipv6->proto);
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.ipv6.drop++;
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#endif
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}
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dev->d_len = 0;
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return OK;
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}
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return -EPFNOSUPPORT;
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}
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#else
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# define ipv6_packet_conversion(dev, ipv6)
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#endif /* CONFIG_NET_6LOWPAN */
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/****************************************************************************
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* Name: ipv6_hdrsize
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*
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* Description:
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* Return the size of the IPv6 header and the following.
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*
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* Input Parameters:
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* ipv6 - A pointer to the IPv6 header in within the IPv6 packet. This
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* is immeidately followed by the L3 header which may be TCP, UDP,
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* or ICMPv6.
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*
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* Returned Value:
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* The size of the combined L2 + L3 headers is returned on success. An
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* error is returned only if the prototype is not supported.
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*
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****************************************************************************/
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static int ipv6_hdrsize(FAR struct ipv6_hdr_s *ipv6)
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{
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/* Size is determined by the following protocol header, */
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switch (ipv6->proto)
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{
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#ifdef CONFIG_NET_TCP
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case IP_PROTO_TCP:
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{
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FAR struct tcp_hdr_s *tcp =
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(FAR struct tcp_hdr_s *)((FAR uintptr_t *)ipv6 + IPv6_HDRLEN);
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unsigned int tcpsize;
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/* The TCP header length is encoded in the top 4 bits of the
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* tcpoffset field (in units of 32-bit words).
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*/
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tcpsize = ((uint16_t)tcp->tcpoffset >> 4) << 2;
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return IPv6_HDRLEN + tcpsize;
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}
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break;
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#endif
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#ifdef CONFIG_NET_UDP
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case IP_PROTO_UDP:
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return IPv6_HDRLEN + UDP_HDRLEN;
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break;
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#endif
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#ifdef CONFIG_NET_ICMPv6
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case IP_PROTO_ICMP6:
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return IPv6_HDRLEN + ICMPv6_HDRLEN;
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break;
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#endif
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default:
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nwarn("WARNING: Unrecognized proto: %u\n", ipv6->proto);
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return -EPROTONOSUPPORT;
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}
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}
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/****************************************************************************
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* Name: ipv6_dev_forward
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*
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* Description:
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* Set up to forward the UDP or ICMPv6 packet on the specified device.
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* This function will set up a send "interrupt" handler that will perform
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* the actual send asynchronously and must return without waiting for the
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* send to complete.
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*
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* Input Parameters:
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* dev - The device on which the packet should be forwarded.
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* ipv6 - A pointer to the IPv6 header in within the IPv6 packet. This
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* is immeidately followed by the L3 header which may be UDP or
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* ICMPv6.
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* iob - A list of IOBs containing the data payload to be sent.
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*
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* Returned Value:
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* Zero is returned if the packet was successfully forwarded; A negated
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* errno value is returned if the packet is not forwardable. In that
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* latter case, the caller should free the IOB list and drop the packet.
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*
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****************************************************************************/
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#if defined(CONFIG_NETDEV_MULTINIC)
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static int ipv6_dev_forward(FAR struct net_driver_s *dev,
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FAR struct ipv6_hdr_s *ipv6,
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FAR struct iob_s *iob)
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{
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/* Notify the forwarding device that TX data is available */
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/* Set up to send the packet when the selected device polls for TX data. */
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#warning Missing logic
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/* REVISIT: For Ethernet we may have to fix up the Ethernet header:
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* - source MAC, the MAC of the current device.
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* - dest MAC, the MAC associated with the destination IPv6 adress.
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* This will involve ICMPv6 and Neighbor Discovery.
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*/
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nwarn("WARNING: UPD/ICMPv6 packet forwarding not yet supported\n");
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return -ENOSYS;
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}
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#endif
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/****************************************************************************
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* Name: ipv6_dropstats
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*
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* Description:
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* Update statistics for a droped packet.
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*
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* Input Parameters:
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* ipv6 - A convenience pointer to the IPv6 header in within the IPv6
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* packet to be dropped.
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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#ifdef CONFIG_NET_STATISTICS
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static void ipv6_dropstats(FAR struct ipv6_hdr_s *ipv)
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{
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switch (ipv6->proto)
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{
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#ifdef CONFIG_NET_TCP
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case IP_PROTO_TCP:
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g_netstats.tcp.drop++;
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break;
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#endif
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#ifdef CONFIG_NET_UDP
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case IP_PROTO_UDP:
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g_netstats.udp.drop++;
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break;
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#endif
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#ifdef CONFIG_NET_ICMPv6
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case IP_PROTO_ICMP6:
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g_netstats.icmpv6.drop++
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break;
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#endif
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default:
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break;
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}
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g_netstats.ipv6.drop++
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}
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#else
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# define ipv6_dropstats(ipv6)
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: ipv6_forward
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*
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* Description:
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* This function is called from ipv6_input when a packet is received that
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* is not destined for us. In this case, the packet may need to be
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* forwarded to another device (or sent back out the same device)
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* depending configuration, routing table information, and the IPv6
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* networks served by various network devices.
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*
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* Input Parameters:
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* dev - The device on which the packet was received and which contains
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* the IPv6 packet.
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* ipv6 - A convenience pointer to the IPv6 header in within the IPv6
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* packet
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*
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* On input:
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* - dev->d_buf holds the received packet.
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* - dev->d_len holds the length of the received packet MINUS the
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* size of the L1 header. That was subtracted out by ipv6_input.
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* - ipv6 points to the IPv6 header with dev->d_buf.
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*
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* Returned Value:
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* Zero is returned if the packet was successfully forward; A negated
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* errno value is returned if the packet is not forwardable. In that
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* latter case, the caller (ipv6_input()) should drop the packet.
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*
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****************************************************************************/
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int ipv6_forward(FAR struct net_driver_s *dev, FAR struct ipv6_hdr_s *ipv6)
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{
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/* Multiple network devices */
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FAR struct net_driver_s *fwddev;
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int ret;
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/* Search for a device that can forward this packet. This is a trivial
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* serch if there is only a single network device (CONFIG_NETDEV_MULTINIC
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* not defined). But netdev_findby_ipv6addr() will still assure
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* routability in that case.
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*/
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#ifdef CONFIG_NETDEV_MULTINIC
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fwddev = netdev_findby_ipv6addr(ipv6->srcipaddr, ipv6->destipaddr);
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#else
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fwddev = netdev_findby_ipv6addr(ipv6->destipaddr);
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#endif
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if (fwddev == NULL)
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{
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nwarn("WARNING: Not routable\n");
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return (ssize_t)-ENETUNREACH;
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}
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#if defined(CONFIG_NETDEV_MULTINIC)
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/* Check if we are forwarding on the same device that we received the
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* packet from.
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*/
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if (fwddev != dev)
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{
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/* Perform any necessary packet conversions. */
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ret = ipv6_packet_conversion(dev, fwddev, ipv6);
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if (ret < 0)
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{
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FAR struct iob_s *iob = NULL;
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FAR uint8_t *payload;
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unsigned int paysize;
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int hdrsize;
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/* Get the size of the IPv6 + L3 header. Use this to determine
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* start of the data payload.
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*
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* Remember that the size of the L1 header has already been
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* subtracted from dev->d_len.
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*/
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hdrsize = ipv6_hdrsize(ipv6);
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if (hdrsize < 0)
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{
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goto drop;
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}
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payload = (FAR uint8_t *)ipv6 + hdrsize;
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paysize = dev->d_len - hdrsize;
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if (paysize > 0)
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{
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/* Try to allocate the head of an IOB chain. If this fails,
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* the the packet will be dropped; we are not operating in a
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* context where waiting for an IOB is a good idea
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*/
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iob = iob_tryalloc(false);
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if (iob == NULL)
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{
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ret = -ENOMEM;
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goto errout_with_iob;
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}
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/* Copy the packet data payload into an IOB chain.
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* iob_trycopin() will not wait, but will fail there are no
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* available IOBs.
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*/
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ret = iob_trycopyin(iob, payload, paysize, 0);
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if (ret < 0)
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{
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goto errout_with_iob;
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}
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}
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/* Then set up to forward the packet */
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if (ipv6->proto == IP_PROTO_TCP)
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{
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ret = tcp_ipv6_forward(fwddev, ipv6, iob);
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}
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else
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{
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ret = ipv6_dev_forward(fwddev, ipv6, iob);
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}
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if (ret >= 0)
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{
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dev->d_len = 0;
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return OK;
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}
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errout_with_iob:
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iob_free_chain(iob);
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drop:
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ipv6_dropstats(ipv6);
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dev->d_len = 0;
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return -ENOSYS;
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}
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}
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else
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#endif /* CONFIG_NETDEV_MULTINIC */
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#if defined(CONFIG_NET_6LOWPAN) /* REVISIT: Currently only suport for 6LoWPAN */
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{
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/* Single network device */
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/* Perform any necessary packet conversions. If the packet was handled
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* via a backdoor path (or dropped), then dev->d_len will be zero. If
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* the packet needs to be forwarded in the normal manner then
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* dev->d_len will be unchanged.
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*/
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ret = ipv6_packet_conversion(dev, dev, ipv6);
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if (ret < 0)
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{
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#ifdef CONFIG_NET_ETHERNET
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/* REVISIT: For Ethernet we may have to fix up the Ethernet header:
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* - source MAC, the MAC of the current device.
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* - dest MAC, the MAC associated with the destination IPv6 adress.
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* This will involve ICMPv6 and Neighbor Discovery.
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*/
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/* Correct dev->d_buf by adding back the L1 header length */
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#endif
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/* Nothing other 6LoWPAN forwarding is currently handled and that
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* case was dealt with in ipv6_packet_conversion().
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*/
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# warning Missing logic
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nwarn("WARNING: Packet forwarding supported only for 6LoWPAN\n");
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return -ENOSYS;
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}
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}
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#else /* CONFIG_NET_6LOWPAN */
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{
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nwarn("WARNING: Packet forwarding not supported in this configuration\n");
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return -ENOSYS;
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}
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#endif /* CONFIG_NET_6LOWPAN */
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/* Return success. ipv6_input will return to the network driver with
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* dev->d_len set to the packet size and the network driver will perform
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* the transfer.
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*/
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return OK;
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}
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#endif /* CONFIG_NET_IPFORWARD && CONFIG_NET_IPv6 */
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