518 lines
16 KiB
C
518 lines
16 KiB
C
/****************************************************************************
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* net/devif/ipv4_input.c
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* Device driver IPv4 packet receipt interface
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*
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* Copyright (C) 2007-2009, 2013-2015 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Adapted for NuttX from logic in uIP which also has a BSD-like license:
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*
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* uIP is an implementation of the TCP/IP protocol stack intended for
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* small 8-bit and 16-bit microcontrollers.
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*
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* uIP provides the necessary protocols for Internet communication,
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* with a very small code footprint and RAM requirements - the uIP
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* code size is on the order of a few kilobytes and RAM usage is on
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* the order of a few hundred bytes.
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*
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* Original author Adam Dunkels <adam@dunkels.com>
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* Copyright () 2001-2003, Adam Dunkels.
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* All rights reserved.
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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 the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* uIP is a small implementation of the IP, UDP and TCP protocols (as
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* well as some basic ICMP stuff). The implementation couples the IP,
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* UDP, TCP and the application layers very tightly. To keep the size
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* of the compiled code down, this code frequently uses the goto
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* statement. While it would be possible to break the ipv4_input()
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* function into many smaller functions, this would increase the code
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* size because of the overhead of parameter passing and the fact that
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* the optimizer would not be as efficient.
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*
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* The principle is that we have a small buffer, called the d_buf,
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* in which the device driver puts an incoming packet. The TCP/IP
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* stack parses the headers in the packet, and calls the
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* application. If the remote host has sent data to the application,
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* this data is present in the d_buf and the application read the
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* data from there. It is up to the application to put this data into
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* a byte stream if needed. The application will not be fed with data
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* that is out of sequence.
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*
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* If the application wishes to send data to the peer, it should put
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* its data into the d_buf. The d_appdata pointer points to the
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* first available byte. The TCP/IP stack will calculate the
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* checksums, and fill in the necessary header fields and finally send
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* the packet back to the peer.
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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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#ifdef CONFIG_NET_IPv4
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#include <sys/ioctl.h>
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#include <stdint.h>
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#include <debug.h>
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#include <string.h>
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#include <net/if.h>
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#include <nuttx/net/netconfig.h>
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#include <nuttx/net/netdev.h>
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#include <nuttx/net/netstats.h>
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#include <nuttx/net/ip.h>
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#include "tcp/tcp.h"
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#include "udp/udp.h"
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#include "pkt/pkt.h"
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#include "icmp/icmp.h"
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#include "igmp/igmp.h"
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#include "devif/devif.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Macros */
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#define BUF ((FAR struct ipv4_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)])
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#define FBUF ((FAR struct ipv4_hdr_s *)&g_reassembly_buffer[0])
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/* IP fragment re-assembly */
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#define IP_MF 0x20 /* See IP_FLAG_MOREFRAGS */
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#define TCP_REASS_BUFSIZE (NET_DEV_MTU(dev) - NET_LL_HDRLEN(dev))
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#define TCP_REASS_LASTFRAG 0x01
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/****************************************************************************
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* Public Data
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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#if defined(CONFIG_NET_TCP_REASSEMBLY) && !defined(CONFIG_NET_IPv6)
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static uint8_t g_reassembly_buffer[TCP_REASS_BUFSIZE];
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static uint8_t g_reassembly_bitmap[TCP_REASS_BUFSIZE / (8 * 8)];
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static const uint8_t g_bitmap_bits[8] =
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{0xff, 0x7f, 0x3f, 0x1f, 0x0f, 0x07, 0x03, 0x01};
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static uint16_t g_reassembly_len;
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static uint8_t g_reassembly_flags;
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#endif /* CONFIG_NET_TCP_REASSEMBLY */
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Function: devif_reassembly
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*
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* Description:
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* IP fragment reassembly: not well-tested.
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*
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* Assumptions:
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*
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****************************************************************************/
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#if defined(CONFIG_NET_TCP_REASSEMBLY) && !defined(CONFIG_NET_IPv6)
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static uint8_t devif_reassembly(void)
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{
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FAR struct ipv4_hdr_s *pbuf = BUF;
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FAR struct ipv4_hdr_s *pfbuf = FBUF;
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uint16_t offset;
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uint16_t len;
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uint16_t i;
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/* If g_reassembly_timer is zero, no packet is present in the buffer, so
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* we write the IP header of the fragment into the reassembly buffer. The
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* timer is updated with the maximum age.
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*/
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if (!g_reassembly_timer)
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{
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memcpy(g_reassembly_buffer, &pbuf->vhl, IPv4_HDRLEN);
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g_reassembly_timer = CONFIG_NET_TCP_REASS_MAXAGE;
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g_reassembly_flags = 0;
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/* Clear the bitmap. */
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memset(g_reassembly_bitmap, 0, sizeof(g_reassembly_bitmap));
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}
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/* Check if the incoming fragment matches the one currently present
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* in the reassembly buffer. If so, we proceed with copying the
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* fragment into the buffer.
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*/
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if (net_ipv4addr_hdrcmp(pbuf->srcipaddr, pfbuf->srcipaddr) &&
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net_ipv4addr_hdrcmp(pbuf->destipaddr, pfbuf->destipaddr) &&
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pbuf->g_ipid[0] == pfbuf->g_ipid[0] && pbuf->g_ipid[1] == pfbuf->g_ipid[1])
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{
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len = (pbuf->len[0] << 8) + pbuf->len[1] - (pbuf->vhl & 0x0f) * 4;
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offset = (((pbuf->ipoffset[0] & 0x3f) << 8) + pbuf->ipoffset[1]) * 8;
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/* If the offset or the offset + fragment length overflows the
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* reassembly buffer, we discard the entire packet.
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*/
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if (offset > TCP_REASS_BUFSIZE || offset + len > TCP_REASS_BUFSIZE)
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{
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g_reassembly_timer = 0;
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goto nullreturn;
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}
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/* Copy the fragment into the reassembly buffer, at the right offset. */
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memcpy(&g_reassembly_buffer[IPv4_HDRLEN + offset], (char *)pbuf + (int)((pbuf->vhl & 0x0f) * 4), len);
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/* Update the bitmap. */
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if (offset / (8 * 8) == (offset + len) / (8 * 8))
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{
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/* If the two endpoints are in the same byte, we only update that byte. */
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g_reassembly_bitmap[offset / (8 * 8)] |=
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g_bitmap_bits[(offset / 8 ) & 7] & ~g_bitmap_bits[((offset + len) / 8 ) & 7];
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}
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else
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{
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/* If the two endpoints are in different bytes, we update the bytes
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* in the endpoints and fill the stuff inbetween with 0xff.
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*/
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g_reassembly_bitmap[offset / (8 * 8)] |= g_bitmap_bits[(offset / 8 ) & 7];
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for (i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i)
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{
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g_reassembly_bitmap[i] = 0xff;
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}
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g_reassembly_bitmap[(offset + len) / (8 * 8)] |=
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~g_bitmap_bits[((offset + len) / 8 ) & 7];
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}
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/* If this fragment has the More Fragments flag set to zero, we know that
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* this is the last fragment, so we can calculate the size of the entire
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* packet. We also set the IP_REASS_FLAG_LASTFRAG flag to indicate that
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* we have received the final fragment.
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*/
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if ((pbuf->ipoffset[0] & IP_MF) == 0)
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{
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g_reassembly_flags |= TCP_REASS_LASTFRAG;
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g_reassembly_len = offset + len;
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}
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/* Finally, we check if we have a full packet in the buffer. We do this
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* by checking if we have the last fragment and if all bits in the bitmap
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* are set.
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*/
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if (g_reassembly_flags & TCP_REASS_LASTFRAG)
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{
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/* Check all bytes up to and including all but the last byte in
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* the bitmap.
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*/
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for (i = 0; i < g_reassembly_len / (8 * 8) - 1; ++i)
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{
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if (g_reassembly_bitmap[i] != 0xff)
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{
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goto nullreturn;
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}
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}
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/* Check the last byte in the bitmap. It should contain just the
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* right amount of bits.
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*/
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if (g_reassembly_bitmap[g_reassembly_len / (8 * 8)] != (uint8_t)~g_bitmap_bits[g_reassembly_len / 8 & 7])
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{
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goto nullreturn;
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}
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/* If we have come this far, we have a full packet in the buffer,
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* so we allocate a pbuf and copy the packet into it. We also reset
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* the timer.
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*/
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g_reassembly_timer = 0;
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memcpy(pbuf, pfbuf, g_reassembly_len);
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/* Pretend to be a "normal" (i.e., not fragmented) IP packet from
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* now on.
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*/
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pbuf->ipoffset[0] = pbuf->ipoffset[1] = 0;
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pbuf->len[0] = g_reassembly_len >> 8;
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pbuf->len[1] = g_reassembly_len & 0xff;
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pbuf->ipchksum = 0;
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pbuf->ipchksum = ~(ipv4_chksum(dev));
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return g_reassembly_len;
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}
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}
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nullreturn:
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return 0;
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}
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#endif /* CONFIG_NET_TCP_REASSEMBLY */
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Function: ipv4_input
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*
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* Description:
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*
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* Returned Value:
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* OK The packet was processed (or dropped) and can be discarded.
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* ERROR There is a matching connection, but could not dispatch the packet
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* yet. Currently useful for UDP when a packet arrives before a recv
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* call is in place.
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*
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* Assumptions:
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*
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****************************************************************************/
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int ipv4_input(FAR struct net_driver_s *dev)
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{
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FAR struct ipv4_hdr_s *pbuf = BUF;
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uint16_t iplen;
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/* This is where the input processing starts. */
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.ipv4.recv++;
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#endif
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/* Start of IP input header processing code. */
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/* Check validity of the IP header. */
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if (pbuf->vhl != 0x45)
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{
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/* IP version and header length. */
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.ipv4.drop++;
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g_netstats.ipv4.vhlerr++;
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#endif
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nlldbg("Invalid IP version or header length: %02x\n", pbuf->vhl);
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goto drop;
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}
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/* Check the size of the packet. If the size reported to us in d_len is
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* smaller the size reported in the IP header, we assume that the packet
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* has been corrupted in transit. If the size of d_len is larger than the
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* size reported in the IP packet header, the packet has been padded and
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* we set d_len to the correct value.
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*/
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iplen = (pbuf->len[0] << 8) + pbuf->len[1];
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if (iplen <= dev->d_len)
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{
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dev->d_len = iplen;
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}
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else
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{
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nlldbg("IP packet shorter than length in IP header\n");
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goto drop;
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}
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/* Check the fragment flag. */
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if ((pbuf->ipoffset[0] & 0x3f) != 0 || pbuf->ipoffset[1] != 0)
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{
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#if defined(CONFIG_NET_TCP_REASSEMBLY)
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dev->d_len = devif_reassembly();
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if (dev->d_len == 0)
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{
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goto drop;
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}
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#else /* CONFIG_NET_TCP_REASSEMBLY */
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.ipv4.drop++;
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g_netstats.ipv4.fragerr++;
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#endif
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nlldbg("IP fragment dropped\n");
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goto drop;
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#endif /* CONFIG_NET_TCP_REASSEMBLY */
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}
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/* If IP broadcast support is configured, we check for a broadcast
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* UDP packet, which may be destined to us (even if there is no IP
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* address yet assigned to the device as is the case when we are
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* negotiating over DHCP for an address).
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*/
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#if defined(CONFIG_NET_BROADCAST) && defined(CONFIG_NET_UDP)
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if (pbuf->proto == IP_PROTO_UDP &&
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net_ipv4addr_cmp(net_ip4addr_conv32(pbuf->destipaddr),
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g_ipv4_alloneaddr))
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{
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return udp_ipv4_input(dev);
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}
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/* In most other cases, the device must be assigned a non-zero IP
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* address. Another exception is when CONFIG_NET_PINGADDRCONF is
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* enabled...
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*/
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else
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#endif
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#ifdef CONFIG_NET_ICMP
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if (net_ipv4addr_cmp(dev->d_ipaddr, g_ipv4_allzeroaddr))
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{
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/* If we are configured to use ping IP address configuration and
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* hasn't been assigned an IP address yet, we accept all ICMP
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* packets.
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*/
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#ifdef CONFIG_NET_PINGADDRCONF
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if (pbuf->proto == IP_PROTO_ICMP)
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{
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nlldbg("Possible ping config packet received\n");
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icmp_input(dev);
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goto drop;
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}
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else
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#endif
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{
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nlldbg("No IP address assigned\n");
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goto drop;
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}
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}
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/* Check if the packet is destined for out IP address */
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else
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#endif
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{
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/* Check if the packet is destined for our IP address. */
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if (!net_ipv4addr_cmp(net_ip4addr_conv32(pbuf->destipaddr), dev->d_ipaddr))
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{
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#ifdef CONFIG_NET_IGMP
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in_addr_t destip = net_ip4addr_conv32(pbuf->destipaddr);
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if (igmp_grpfind(dev, &destip) == NULL)
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#endif
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{
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.ipv4.drop++;
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#endif
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goto drop;
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}
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}
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}
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if (ipv4_chksum(dev) != 0xffff)
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{
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/* Compute and check the IP header checksum. */
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.ipv4.drop++;
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g_netstats.ipv4.chkerr++;
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#endif
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nlldbg("Bad IP checksum\n");
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goto drop;
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}
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/* Make sure that all packet processing logic knows that there is an IPv4
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* packet in the device buffer.
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*/
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IFF_SET_IPv4(dev->d_flags);
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/* Now process the incoming packet according to the protocol. */
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switch (pbuf->proto)
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{
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#ifdef CONFIG_NET_TCP
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case IP_PROTO_TCP: /* TCP input */
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tcp_ipv4_input(dev);
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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: /* UDP input */
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udp_ipv4_input(dev);
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break;
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#endif
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/* Check for ICMP input */
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#ifdef CONFIG_NET_ICMP
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case IP_PROTO_ICMP: /* ICMP input */
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icmp_input(dev);
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break;
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#endif
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/* Check for IGMP input */
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#ifdef CONFIG_NET_IGMP
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case IP_PROTO_IGMP: /* IGMP input */
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igmp_input(dev);
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break;
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#endif
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default: /* Unrecognized/unsupported protocol */
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.ipv4.drop++;
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g_netstats.ipv4.protoerr++;
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#endif
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nlldbg("Unrecognized IP protocol\n");
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goto drop;
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}
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/* Return and let the caller do any pending transmission. */
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return OK;
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/* Drop the packet. NOTE that OK is returned meaning that the
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* packet has been processed (although processed unsuccessfully).
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*/
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drop:
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dev->d_len = 0;
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return OK;
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}
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#endif /* CONFIG_NET_IPv4 */
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