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incubator-nuttx/net/uip/uip-input.c

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/****************************************************************************
* net/uip/uip-input.c
* The uIP TCP/IP stack code.
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 uip_input()
* function into many smaller functions, this would increase the code
* size because of the overhead of parameter passing and the fact that
* the optimier 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 whishes 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
#include <sys/types.h>
#include <sys/ioctl.h>
#include <debug.h>
#include <string.h>
#include <net/uip/uipopt.h>
#include <net/uip/uip.h>
#include <net/uip/uip-arch.h>
#ifdef CONFIG_NET_IPv6
# include "uip-neighbor.h"
#endif /* CONFIG_NET_IPv6 */
#include "uip-internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/* Macros. */
#define BUF ((struct uip_ip_hdr *)&dev->d_buf[UIP_LLH_LEN])
#define FBUF ((struct uip_ip_hdr *)&uip_reassbuf[0])
/* IP fragment re-assembly */
#define IP_MF 0x20
#define UIP_REASS_BUFSIZE (CONFIG_NET_BUFSIZE - UIP_LLH_LEN)
#define UIP_REASS_FLAG_LASTFRAG 0x01
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
#if UIP_REASSEMBLY && !defined(CONFIG_NET_IPv6)
static uint8 uip_reassbuf[UIP_REASS_BUFSIZE];
static uint8 uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)];
static const uint8 bitmap_bits[8] = {0xff, 0x7f, 0x3f, 0x1f, 0x0f, 0x07, 0x03, 0x01};
static uint16 uip_reasslen;
static uint8 uip_reassflags;
#endif /* UIP_REASSEMBLY */
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Function: uip_reass
*
* Description:
* IP fragment reassembly: not well-tested.
*
* Assumptions:
*
****************************************************************************/
#if UIP_REASSEMBLY && !defined(CONFIG_NET_IPv6)
static uint8 uip_reass(void)
{
uint16 offset, len;
uint16 i;
/* If uip_reasstmr is zero, no packet is present in the buffer, so we
* write the IP header of the fragment into the reassembly
* buffer. The timer is updated with the maximum age.
*/
if (!uip_reasstmr)
{
memcpy(uip_reassbuf, &BUF->vhl, UIP_IPH_LEN);
uip_reasstmr = UIP_REASS_MAXAGE;
uip_reassflags = 0;
/* Clear the bitmap. */
memset(uip_reassbitmap, 0, sizeof(uip_reassbitmap));
}
/* Check if the incoming fragment matches the one currently present
* in the reasembly buffer. If so, we proceed with copying the
* fragment into the buffer.
*/
if (uiphdr_addr_cmp(BUF->srcipaddr, FBUF->srcipaddr) &&
uiphdr_addr_cmp(BUF->destipaddr == FBUF->destipaddr) &&
BUF->g_ipid[0] == FBUF->g_ipid[0] && BUF->g_ipid[1] == FBUF->g_ipid[1])
{
len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4;
offset = (((BUF->ipoffset[0] & 0x3f) << 8) + BUF->ipoffset[1]) * 8;
/* If the offset or the offset + fragment length overflows the
* reassembly buffer, we discard the entire packet.
*/
if (offset > UIP_REASS_BUFSIZE || offset + len > UIP_REASS_BUFSIZE)
{
uip_reasstmr = 0;
goto nullreturn;
}
/* Copy the fragment into the reassembly buffer, at the right offset. */
memcpy(&uip_reassbuf[UIP_IPH_LEN + offset], (char *)BUF + (int)((BUF->vhl & 0x0f) * 4), len);
/* Update the bitmap. */
if (offset / (8 * 8) == (offset + len) / (8 * 8))
{
/* If the two endpoints are in the same byte, we only update that byte. */
uip_reassbitmap[offset / (8 * 8)] |=
bitmap_bits[(offset / 8 ) & 7] & ~bitmap_bits[((offset + len) / 8 ) & 7];
}
else
{
/* If the two endpoints are in different bytes, we update the bytes
* in the endpoints and fill the stuff inbetween with 0xff.
*/
uip_reassbitmap[offset / (8 * 8)] |= bitmap_bits[(offset / 8 ) & 7];
for (i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i)
{
uip_reassbitmap[i] = 0xff;
}
uip_reassbitmap[(offset + len) / (8 * 8)] |= ~bitmap_bits[((offset + len) / 8 ) & 7];
}
/* If this fragment has the More Fragments flag set to zero, we know that
* this is the last fragment, so we can calculate the size of the entire
* packet. We also set the IP_REASS_FLAG_LASTFRAG flag to indicate that
* we have received the final fragment.
*/
if ((BUF->ipoffset[0] & IP_MF) == 0)
{
uip_reassflags |= UIP_REASS_FLAG_LASTFRAG;
uip_reasslen = offset + len;
}
/* Finally, we check if we have a full packet in the buffer. We do this
* by checking if we have the last fragment and if all bits in the bitmap
* are set.
*/
if (uip_reassflags & UIP_REASS_FLAG_LASTFRAG)
{
/* Check all bytes up to and including all but the last byte in
* the bitmap.
*/
for (i = 0; i < uip_reasslen / (8 * 8) - 1; ++i)
{
if (uip_reassbitmap[i] != 0xff)
{
goto nullreturn;
}
}
/* Check the last byte in the bitmap. It should contain just the
* right amount of bits.
*/
if (uip_reassbitmap[uip_reasslen / (8 * 8)] != (uint8)~bitmap_bits[uip_reasslen / 8 & 7])
{
goto nullreturn;
}
/* If we have come this far, we have a full packet in the buffer,
* so we allocate a pbuf and copy the packet into it. We also reset
* the timer.
*/
uip_reasstmr = 0;
memcpy(BUF, FBUF, uip_reasslen);
/* Pretend to be a "normal" (i.e., not fragmented) IP packet from
* now on.
*/
BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
BUF->len[0] = uip_reasslen >> 8;
BUF->len[1] = uip_reasslen & 0xff;
BUF->ipchksum = 0;
BUF->ipchksum = ~(uip_ipchksum(dev));
return uip_reasslen;
}
}
nullreturn:
return 0;
}
#endif /* UIP_REASSEMBLY */
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: uip_input
*
* Description:
*
* Assumptions:
*
****************************************************************************/
void uip_input(struct uip_driver_s *dev)
{
/* This is where the input processing starts. */
#ifdef CONFIG_NET_STATISTICS
uip_stat.ip.recv++;
#endif
/* Start of IP input header processing code. */
#ifdef CONFIG_NET_IPv6
/* Check validity of the IP header. */
if ((BUF->vtc & 0xf0) != 0x60)
{
/* IP version and header length. */
#ifdef CONFIG_NET_STATISTICS
uip_stat.ip.drop++;
uip_stat.ip.vhlerr++;
#endif
ndbg("Invalid IPv6 version: %d\n", BUF->vtc >> 4);
goto drop;
}
#else /* CONFIG_NET_IPv6 */
/* Check validity of the IP header. */
if (BUF->vhl != 0x45)
{
/* IP version and header length. */
#ifdef CONFIG_NET_STATISTICS
uip_stat.ip.drop++;
uip_stat.ip.vhlerr++;
#endif
ndbg("Invalid IP version or header length: %02x\n", BUF->vhl);
goto drop;
}
#endif /* CONFIG_NET_IPv6 */
/* 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.
*/
if ((BUF->len[0] << 8) + BUF->len[1] <= dev->d_len)
{
dev->d_len = (BUF->len[0] << 8) + BUF->len[1];
#ifdef CONFIG_NET_IPv6
/* The length reported in the IPv6 header is the length of the
* payload that follows the header. However, uIP uses the d_len
* variable for holding the size of the entire packet, including the
* IP header. For IPv4 this is not a problem as the length field in
* the IPv4 header contains the length of the entire packet. But
* for IPv6 we need to add the size of the IPv6 header (40 bytes).
*/
dev->d_len += 40;
#endif /* CONFIG_NET_IPv6 */
}
else
{
ndbg("IP packet shorter than length in IP header\n");
goto drop;
}
#ifndef CONFIG_NET_IPv6
/* Check the fragment flag. */
if ((BUF->ipoffset[0] & 0x3f) != 0 || BUF->ipoffset[1] != 0)
{
#if UIP_REASSEMBLY
dev->d_len = uip_reass();
if (dev->d_len == 0)
{
goto drop;
}
#else /* UIP_REASSEMBLY */
#ifdef CONFIG_NET_STATISTICS
uip_stat.ip.drop++;
uip_stat.ip.fragerr++;
#endif
ndbg("IP fragment dropped\n");
goto drop;
#endif /* UIP_REASSEMBLY */
}
#endif /* CONFIG_NET_IPv6 */
/* If IP broadcast support is configured, we check for a broadcast
* UDP packet, which may be destined to us (even if there is no IP
* address yet assigned to the device as is the case when we are
* negotiating over DHCP for an address).
*/
#if defined(CONFIG_NET_BROADCAST) && defined(CONFIG_NET_UDP)
if (BUF->proto == UIP_PROTO_UDP &&
#ifndef CONFIG_NET_IPv6
uip_ipaddr_cmp(uip_ip4addr_conv(BUF->destipaddr), g_alloneaddr))
#else
uip_ipaddr_cmp(BUF->destipaddr, g_alloneaddr))
#endif
{
uip_udpinput(dev);
return;
}
/* In most other cases, the device must be assigned a non-zero IP
* address. Another exception is when CONFIG_NET_PINGADDRCONF is
* enabled...
*/
else
#endif
if (uip_ipaddr_cmp(dev->d_ipaddr, g_allzeroaddr))
{
/* If we are configured to use ping IP address configuration and
* hasn't been assigned an IP address yet, we accept all ICMP
* packets.
*/
#if defined(CONFIG_NET_PINGADDRCONF) && !defined(CONFIG_NET_IPv6)
if (BUF->proto == UIP_PROTO_ICMP)
{
ndbg("Possible ping config packet received\n");
uip_icmpinput(dev);
goto done;
}
else
#endif
{
ndbg("No IP address assigned\n");
goto drop;
}
}
/* Check if the pack is destined for out IP address */
else
{
/* Check if the packet is destined for our IP address. */
#ifndef CONFIG_NET_IPv6
if (!uip_ipaddr_cmp(uip_ip4addr_conv(BUF->destipaddr), dev->d_ipaddr))
{
#ifdef CONFIG_NET_STATISTICS
uip_stat.ip.drop++;
#endif
goto drop;
}
#else /* CONFIG_NET_IPv6 */
/* 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 (!uip_ipaddr_cmp(BUF->destipaddr, dev->d_ipaddr) &&
BUF->destipaddr & HTONL(0xffff0000) != HTONL(0xff020000))
{
#ifdef CONFIG_NET_STATISTICS
uip_stat.ip.drop++;
#endif
goto drop;
}
#endif /* CONFIG_NET_IPv6 */
}
#ifndef CONFIG_NET_IPv6
if (uip_ipchksum(dev) != 0xffff)
{
/* Compute and check the IP header checksum. */
#ifdef CONFIG_NET_STATISTICS
uip_stat.ip.drop++;
uip_stat.ip.chkerr++;
#endif
ndbg("Bad IP checksum\n");
goto drop;
}
#endif /* CONFIG_NET_IPv6 */
/* Everything looks good so far. Now process the incoming packet
* according to the protocol.
*/
switch (BUF->proto)
{
#ifdef CONFIG_NET_TCP
case UIP_PROTO_TCP: /* TCP input */
uip_tcpinput(dev);
break;
#endif
#ifdef CONFIG_NET_UDP
case UIP_PROTO_UDP: /* UDP input */
uip_udpinput(dev);
break;
#endif
/* Check for ICMP input */
#ifdef CONFIG_NET_ICMP
#ifndef CONFIG_NET_IPv6
case UIP_PROTO_ICMP: /* ICMP input */
#else
case UIP_PROTO_ICMP6: /* ICMP6 input */
#endif
uip_icmpinput(dev);
break;
#endif
default: /* Unrecognized/unsupported protocol */
#ifdef CONFIG_NET_STATISTICS
uip_stat.ip.drop++;
uip_stat.ip.protoerr++;
#endif
ndbg("Unrecognized IP protocol\n");
goto drop;
}
/* Return and let the caller do any actual transmission. */
return;
drop:
dev->d_len = 0;
}
#endif /* CONFIG_NET */
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