/****************************************************************************
* net/devif/ipv6_input.c
* Device driver IPv6 packet receipt interface
*
* Copyright (C) 2015, 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Adapted for NuttX from logic in uIP which also has a BSD-like license:
*
* uIP is an implementation of the TCP/IP protocol stack intended for
* small 8-bit and 16-bit microcontrollers.
*
* uIP provides the necessary protocols for Internet communication,
* with a very small code footprint and RAM requirements - the uIP
* code size is on the order of a few kilobytes and RAM usage is on
* the order of a few hundred bytes.
*
* Original author Adam Dunkels <adam@dunkels.com>
* Copyright () 2001-2003, Adam Dunkels.
* All rights reserved.
*
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
****************************************************************************/
/****************************************************************************
* uIP is a small implementation of the IP, UDP and TCP protocols (as
* well as some basic ICMP stuff). The implementation couples the IP,
* UDP, TCP and the application layers very tightly. To keep the size
* of the compiled code down, this code frequently uses the goto
* statement. While it would be possible to break the ipv6_input()
* function into many smaller functions, this would increase the code
* size because of the overhead of parameter passing and the fact that
* the optimizer would not be as efficient.
*
* The principle is that we have a small buffer, called the d_buf,
* in which the device driver puts an incoming packet. The TCP/IP
* stack parses the headers in the packet, and calls the
* application. If the remote host has sent data to the application,
* this data is present in the d_buf and the application read the
* data from there. It is up to the application to put this data into
* a byte stream if needed. The application will not be fed with data
* that is out of sequence.
*
* If the application wishes to send data to the peer, it should put
* its data into the d_buf. The d_appdata pointer points to the
* first available byte. The TCP/IP stack will calculate the
* checksums, and fill in the necessary header fields and finally send
* the packet back to the peer.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifdef CONFIG_NET_IPv6
#include <sys/ioctl.h>
#include <stdint.h>
#include <stdbool.h>
#include <debug.h>
#include <string.h>
#include <net/if.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/netstats.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/ipv6ext.h>
#include "neighbor/neighbor.h"
#include "tcp/tcp.h"
#include "udp/udp.h"
#include "sixlowpan/sixlowpan.h"
#include "pkt/pkt.h"
#include "icmpv6/icmpv6.h"
#include "netdev/netdev.h"
#include "ipforward/ipforward.h"
#include "inet/inet.h"
#include "devif/devif.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Macros */
#define IPv6BUF ((FAR struct ipv6_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)])
#define PAYLOAD ((FAR uint8_t *)&dev->d_buf[NET_LL_HDRLEN(dev)] + IPv6_HDRLEN)
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: ipv6_exthdr
*
* Description:
* Return true if the next header value is an IPv6 extension header.
*
****************************************************************************/
static bool ipv6_exthdr(uint8_t nxthdr)
{
switch (nxthdr)
{
case NEXT_HOPBYBOT_EH: /* Hop-by-Hop Options Header */
case NEXT_ENCAP_EH: /* Encapsulated IPv6 Header */
case NEXT_ROUTING_EH: /* Routing Header */
case NEXT_FRAGMENT_EH: /* Fragment Header */
case NEXT_RRSVP_EH: /* Resource ReSerVation Protocol */
case NEXT_ENCAPSEC_EH: /* Encapsulating Security Payload */
case NEXT_AUTH_EH: /* Authentication Header */
case NEXT_DESTOPT_EH: /* Destination Options Header */
case NEXT_MOBILITY_EH: /* Mobility */
case NEXT_HOSTID_EH: /* Host Identity Protocol */
case NEXT_SHIM6_EH: /* Shim6 Protocol */
return true;
case NEXT_NOHEADER: /* No next header */
default:
return false;
}
}
/****************************************************************************
* Name: check_dev_destipaddr
*
* Description:
* Check if the destination address in the IPv6 is destined for the
* provided network device.
*
* Returned Value:
* 1 - This packet is destined for this network device
* 0 - This packet is NOT destined for this network device
*
****************************************************************************/
static int check_dev_destipaddr(FAR struct net_driver_s *dev, FAR void *arg)
{
FAR struct ipv6_hdr_s *ipv6 = (FAR struct ipv6_hdr_s *)arg;
/* Check if the IPv6 destination address matches the IPv6 address assigned
* to this device.
*/
if (net_ipv6addr_cmp(ipv6->destipaddr, dev->d_ipv6addr))
{
return 1;
}
/* No match, return 0 to keep searching */
return 0;
}
/****************************************************************************
* Name: check_destipaddr
*
* Description:
* Check if the destination address in the IPv6 is destined for us. This
* is typically just a comparison the of the IPv6 destination address in
* the IPv6 packet with the IPv6 address assigned to the receiving device.
*
* Input Parameters:
* dev - The device on which the packet was received and which contains
* the IPv6 packet.
* ipv6 - A convenience pointer to the IPv6 header in within the IPv6
* packet
*
* Returned Value:
* true - This packet is destined for us
* false - This packet is NOT destined for us and may need to be forwarded.
*
****************************************************************************/
static bool check_destipaddr(FAR struct net_driver_s *dev,
FAR struct ipv6_hdr_s *ipv6)
{
int ret;
/* For IPv6, packet reception is a little trickier as we need to make sure
* that we listen to certain multicast addresses (all hosts multicast
* address, and the solicited-node multicast address) as well. However,
* we will cheat here and accept all multicast packets that are sent to
* the ff02::/16 addresses.
*/
if (ipv6->destipaddr[0] == HTONS(0xff02))
{
#ifdef CONFIG_NET_IPFORWARD_BROADCAST
/* Forward multicast packets */
ipv6_forward_broadcast(dev, ipv6);
#endif
return true;
}
/* We will also allow for a perverse case where we receive a packet
* addressed to us, but on a different device. Can that really happen?
*/
ret = netdev_foreach(check_dev_destipaddr, ipv6);
if (ret == 1)
{
/* The traversal of the network devices will return 0 if there is
* no network device with that address or 1 if there is a network
* device with such an address.
*/
return true;
}
return false;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ipv6_input
*
* Description:
* Receive an IPv6 packet from the network device. Verify and forward to
* L3 packet handling logic if the packet is destined for us.
*
* Input Parameters:
* dev - The device on which the packet was received and which contains
* the IPv6 packet.
* Returned Value:
* OK - The packet was processed (or dropped) and can be discarded.
* ERROR - Hold the packet and try again later. There is a listening
* socket but no receive in place to catch the packet yet. The
* device's d_len will be set to zero in this case as there is
* no outgoing data.
*
* If this function returns to the network driver with dev->d_len > 0,
* that is an indication to the driver that there is an outgoing response
* to this input.
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
int ipv6_input(FAR struct net_driver_s *dev)
{
FAR struct ipv6_hdr_s *ipv6 = IPv6BUF;
FAR uint8_t *payload;
uint16_t llhdrlen;
uint16_t iphdrlen;
uint16_t paylen;
uint8_t nxthdr;
#ifdef CONFIG_NET_IPFORWARD
int ret;
#endif
/* This is where the input processing starts. */
#ifdef CONFIG_NET_STATISTICS
g_netstats.ipv6.recv++;
#endif
/* Start of IP input header processing code.
*
* Check validity of the IP header.
*/
if ((ipv6->vtc & 0xf0) != 0x60)
{
/* IP version and header length. */
nwarn("WARNING: Invalid IPv6 version: %d\n", ipv6->vtc >> 4);
#ifdef CONFIG_NET_STATISTICS
g_netstats.ipv6.vhlerr++;
#endif
goto drop;
}
/* Get the size of the packet minus the size of link layer header */
llhdrlen = NET_LL_HDRLEN(dev);
if ((llhdrlen + IPv6_HDRLEN) > dev->d_len)
{
nwarn("WARNING: Packet shorter than IPv6 header\n");
goto drop;
}
dev->d_len -= llhdrlen;
/* Make sure that all packet processing logic knows that there is an IPv6
* packet in the device buffer.
*/
IFF_SET_IPv6(dev->d_flags);
/* Check the size of the packet. If the size reported to us in d_len is
* smaller the size reported in the IP header, we assume that the packet
* has been corrupted in transit. If the size of d_len is larger than the
* size reported in the IP packet header, the packet has been padded and
* we set d_len to the correct value.
*
* The length reported in the IPv6 header is the length of the payload
* that follows the header. The device interface uses the d_len variable
* for holding the size of the entire packet, including the IP header but
* without the link layer header (subtracted out above).
*
* NOTE: The payload length in the includes the size of the Ipv6 extension
* options, but not the size of the IPv6 header.
*
* REVISIT: Length will be set to zero if the extension header carries
* a Jumbo payload option.
*/
paylen = ((uint16_t)ipv6->len[0] << 8) + (uint16_t)ipv6->len[1] +
IPv6_HDRLEN;
if (paylen <= dev->d_len)
{
dev->d_len = paylen;
}
else
{
nwarn("WARNING: IP packet shorter than length in IP header\n");
goto drop;
}
/* Parse IPv6 extension headers (parsed but ignored) */
payload = PAYLOAD; /* Assume payload starts right after IPv6 header */
iphdrlen = IPv6_HDRLEN; /* Total length of the IPv6 header */
nxthdr = ipv6->proto; /* Next header determined by IPv6 header prototype */
while (ipv6_exthdr(nxthdr))
{
FAR struct ipv6_extension_s *exthdr;
uint16_t extlen;
/* Just skip over the extension header */
exthdr = (FAR struct ipv6_extension_s *)payload;
extlen = EXTHDR_LEN((unsigned int)exthdr->len);
payload += extlen;
iphdrlen += extlen;
nxthdr = exthdr->nxthdr;
}
#ifdef CONFIG_NET_BROADCAST
/* Check for a multicast packet, which may be destined to us (even if
* there is no IP address yet assigned to the device). We only expect
* multicast packets destined for sockets that have joined a multicast
* group or for ICMPv6 Autoconfiguration and Neighbor discovery or ICMPv6
* MLD packets.
*
* We should actually pick off certain multicast address (all hosts
* multicast address, and the solicited-node multicast address). We
* will cheat here and accept all multicast packets that are sent to the
* ff00::/8 addresses (see net_is_addr_mcast).
*/
if (net_is_addr_mcast(ipv6->destipaddr))
{
#ifdef CONFIG_NET_IPFORWARD_BROADCAST
/* Packets sent to ffx0 are reserved, ffx1 are interface-local, and ffx2
* are interface-local, and therefore, should not be forwarded
*/
if ((ipv6->destipaddr[0] & HTONS(0xff0f) != HTONS(0xff00)) &&
(ipv6->destipaddr[0] & HTONS(0xff0f) != HTONS(0xff01)) &&
(ipv6->destipaddr[0] & HTONS(0xff0f) != HTONS(0xff02)))
{
/* Forward broadcast packets */
ipv6_forward_broadcast(dev, ipv6);
}
#endif
/* Fall through with no further address checks and handle the multicast
* address by its IPv6 nexthdr field.
*/
}
/* In other cases, the device must be assigned a non-zero IP address
* (the all zero address is the "unspecified" address.
*/
else
#endif
#ifdef CONFIG_NET_ICMPv6
if (net_ipv6addr_cmp(dev->d_ipv6addr, g_ipv6_unspecaddr))
{
nwarn("WARNING: No IP address assigned\n");
goto drop;
}
/* Check if the packet is destined for out IP address */
else
#endif
{
/* Check if the packet is destined for us. */
if (!check_destipaddr(dev, ipv6))
{
#ifdef CONFIG_NET_IPFORWARD
/* Not destined for us, try to forward the packet */
ret = ipv6_forward(dev, ipv6);
if (ret >= 0)
{
/* The packet was forwarded. Return success; d_len will
* be set appropriately by the forwarding logic: Cleared
* if the packet is forward via another device or non-
* zero if it will be forwarded by the same device that
* it was received on.
*/
return OK;
}
else
#endif
{
/* Not destined for us and not forwardable... drop the packet. */
nwarn("WARNING: Not destined for us; not forwardable... Dropping!\n");
goto drop;
}
}
}
/* Now process the incoming packet according to the protocol specified in
* the next header IPv6 field.
*/
switch (nxthdr)
{
#ifdef NET_TCP_HAVE_STACK
case IP_PROTO_TCP: /* TCP input */
/* Forward the IPv6 TCP packet */
tcp_ipv6_input(dev, iphdrlen);
#ifdef CONFIG_NET_6LOWPAN
/* TCP output comes through three different mechanisms. Either from:
*
* 1. TCP socket output. For the case of TCP output to an
* IEEE802.15.4, the TCP output is caught in the socket
* send()/sendto() logic and and redirected to 6LoWPAN logic.
* 2. TCP output from the TCP state machine. That will occur
* during TCP packet processing by the TCP state machine.
* 3. TCP output resulting from TX or timer polling
*
* Case 3 is handled here. Logic here detects if (1) an attempt
* to return with d_len > 0 and (2) that the device is an
* IEEE802.15.4 MAC network driver. Under those conditions, 6LoWPAN
* logic will be called to create the IEEE80215.4 frames.
*/
if (dev->d_len > 0 && dev->d_lltype == CONFIG_NET_6LOWPAN)
{
/* Let 6LoWPAN handle the TCP output */
sixlowpan_tcp_send(dev, dev, ipv6);
/* Drop the packet in the d_buf */
goto drop;
}
#endif /* CONFIG_NET_6LOWPAN */
break;
#endif /* NET_TCP_HAVE_STACK */
#ifdef NET_UDP_HAVE_STACK
case IP_PROTO_UDP: /* UDP input */
/* Forward the IPv6 UDP packet */
udp_ipv6_input(dev, iphdrlen);
break;
#endif
/* Check for ICMP input */
#ifdef NET_ICMPv6_HAVE_STACK
case IP_PROTO_ICMP6: /* ICMP6 input */
/* Forward the ICMPv6 packet */
icmpv6_input(dev, iphdrlen);
#ifdef CONFIG_NET_6LOWPAN
/* All outgoing ICMPv6 messages come through one of two mechanisms:
*
* 1. The output from internal ICMPv6 message passing. These
* outgoing messages will use device polling and will be
* handled elsewhere.
* 2. ICMPv6 output resulting from TX or timer polling.
*
* Case 2 is handled here. Logic here detects if (1) an attempt
* to return with d_len > 0 and (2) that the device is an
* IEEE802.15.4 MAC network driver. Under those conditions, 6LoWPAN
* logic will be called to create the IEEE80215.4 frames.
*/
if (dev->d_len > 0 && dev->d_lltype == CONFIG_NET_6LOWPAN)
{
/* Let 6LoWPAN handle the ICMPv6 output */
sixlowpan_icmpv6_send(dev, dev, ipv6);
/* Drop the packet in the d_buf */
goto drop;
}
#endif /* CONFIG_NET_6LOWPAN */
break;
#endif /* NET_ICMPv6_HAVE_STACK */
default: /* Unrecognized/unsupported protocol */
nwarn("WARNING: Unrecognized IP protocol: %04x\n", ipv6->proto);
#ifdef CONFIG_NET_STATISTICS
g_netstats.ipv6.protoerr++;
#endif
goto drop;
}
/* Return and let the caller do any pending transmission. */
return OK;
/* Drop the packet. NOTE that OK is returned meaning that the
* packet has been processed (although processed unsuccessfully).
*/
drop:
#ifdef CONFIG_NET_STATISTICS
g_netstats.ipv6.drop++;
#endif
dev->d_len = 0;
return OK;
}
#endif /* CONFIG_NET_IPv6 */