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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Component */
/** */
/** Internet Protocol (IP) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SOURCE_CODE
/* Include necessary system files. */
#include "nx_api.h"
#include "nx_ip.h"
#include "nx_packet.h"
#include "nx_icmpv4.h"
#include "nx_ipv6.h"
#include "nx_icmpv6.h"
#ifndef NX_DISABLE_FRAGMENTATION
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_ip_fragment_timeout_cleanup PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This internal function cleans up outstanding IP fragments. */
/* */
/* INPUT */
/* */
/* ip_ptr Pointer to IP instance */
/* fragment The head of an IP fragment */
/* that needs to be cleaned. */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_packet_release Release packet */
/* IPv6_Address_Type Find IPv6 address type. */
/* */
/* CALLED BY */
/* */
/* _nx_ip_fragment_timeout_check */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Yuxin Zhou Initial Version 6.0 */
/* 09-30-2020 Yuxin Zhou Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
static VOID _nx_ip_fragment_cleanup(NX_IP *ip_ptr, NX_PACKET *fragment)
{
NX_PACKET *next_fragment;
#if !defined(NX_DISABLE_IPV4) && !defined(NX_DISABLE_ICMPV4_ERROR_MESSAGE)
NX_IPV4_HEADER *ipv4_header;
#endif /* !NX_DISABLE_IPV4 && !NX_DISABLE_ICMPV4_ERROR_MESSAGE */
#if defined(FEATURE_NX_IPV6) && !defined(NX_DISABLE_ICMPV6_ERROR_MESSAGE)
NX_IPV6_HEADER_FRAGMENT_OPTION *fragment_option;
NX_IPV6_HEADER *ipv6_header;
#endif /* FEATURE_NX_IPV6 && !NX_DISABLE_ICMPV6_ERROR_MESSAGE */
#ifndef NX_DISABLE_IP_INFO
/* Increment the re-assembly failures count. */
ip_ptr -> nx_ip_reassembly_failures++;
#endif
#if !defined(NX_DISABLE_IPV4) && !defined(NX_DISABLE_ICMPV4_ERROR_MESSAGE)
/* If ICMPv4 is enabled, send Destination unreachable. */
if (fragment -> nx_packet_ip_version == NX_IP_VERSION_V4)
{
/* Setup header pointer for this packet. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
ipv4_header = (NX_IPV4_HEADER *)fragment -> nx_packet_ip_header;
/* Time Exceeded Message, RFC 792, P2. */
/* Check if the fragment zero is available. */
if ((ipv4_header -> nx_ip_header_word_1 & NX_IP_OFFSET_MASK) == 0)
{
/* Send a time exceeded message if fragmented datagram cannot complete the reassembly. */
NX_ICMPV4_SEND_TIME_EXCEED(ip_ptr, fragment, NX_ICMP_FRT_EXCEEDED_CODE);
}
}
#endif /* !NX_DISABLE_IPV4 && !NX_DISABLE_ICMPV4_ERROR_MESSAGE */
#if defined(FEATURE_NX_IPV6) && !defined(NX_DISABLE_ICMPV6_ERROR_MESSAGE)
/* If the packet is IPv6 type, we need to send out ICMP error message. */
if (fragment -> nx_packet_ip_version == NX_IP_VERSION_V6)
{
/* Send out ICMP Time Exceeded message, if the first fragment has been received
as per RFC2460 4.5 */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
fragment_option = (NX_IPV6_HEADER_FRAGMENT_OPTION *)fragment -> nx_packet_prepend_ptr;
if ((fragment_option -> nx_ipv6_header_fragment_option_offset_flag & 0xFFF8) == 0)
{
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
ipv6_header = (NX_IPV6_HEADER *)fragment -> nx_packet_ip_header;
/* First fragment has been received. Send ICMP error message, if the destination
is not multicast. */
if (!(IPv6_Address_Type(ipv6_header -> nx_ip_header_destination_ip) & IPV6_ADDRESS_MULTICAST))
{
/* Cover offset flag field. */
NX_CHANGE_USHORT_ENDIAN(fragment_option -> nx_ipv6_header_fragment_option_offset_flag);
NX_ICMPV6_SEND_TIME_EXCEED(ip_ptr, fragment, 1);
}
}
}
#endif /* FEATURE_NX_IPV6 && !NX_DISABLE_ICMPV6_ERROR_MESSAGE */
/* Walk the chain of fragments for this fragment re-assembly. */
do
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Pickup the next fragment. */
next_fragment = fragment -> nx_packet_union_next.nx_packet_fragment_next;
/* Reset tcp_queue_next before releasing. */
/*lint -e{923} suppress cast of ULONG to pointer. */
fragment -> nx_packet_union_next.nx_packet_tcp_queue_next = (NX_PACKET *)NX_PACKET_ALLOCATED;
/* Release this fragment. */
_nx_packet_release(fragment);
/* Reassign the fragment pointer. */
fragment = next_fragment;
} while (fragment);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_ip_fragment_timeout_check PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function checks for timeout conditions on the first fragment */
/* in the IP re-assembly list. If the head pointer is the same */
/* between execution of this routine, the head fragment is deleted and */
/* its packets are released. */
/* */
/* INPUT */
/* */
/* ip_ptr Pointer to IP instance */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_packet_release Release packet */
/* */
/* CALLED BY */
/* */
/* Application */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Yuxin Zhou Initial Version 6.0 */
/* 09-30-2020 Yuxin Zhou Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
VOID _nx_ip_fragment_timeout_check(NX_IP *ip_ptr)
{
NX_PACKET *fragment;
NX_PACKET *next_fragment;
NX_PACKET *previous_fragment = NX_NULL;
/* Set a pointer to the head packet of the fragmented packet queue. */
fragment = ip_ptr -> nx_ip_fragment_assembly_head;
/* Loop through all the fragmented packets in the queue. */
while (fragment)
{
/* Check if the timeout has expired. */
if (fragment -> nx_packet_reassembly_time == 0)
{
/* Timeout occured. */
next_fragment = fragment -> nx_packet_queue_next;
/* Remove the packet from the queue and connect the linked list around it. */
if (previous_fragment == NX_NULL)
{
ip_ptr -> nx_ip_fragment_assembly_head = next_fragment;
}
else
{
previous_fragment -> nx_packet_queue_next = next_fragment;
}
/* Send out an error message, release the packet fragments in this chain. */
_nx_ip_fragment_cleanup(ip_ptr, fragment);
/* If this was the last one in the queue, reset the tail to
the previous fragment. */
if (fragment == ip_ptr -> nx_ip_fragment_assembly_tail)
{
ip_ptr -> nx_ip_fragment_assembly_tail = previous_fragment;
}
/* Get the next fragmented packet awaiting assembly. */
fragment = next_fragment;
}
else
{
/* Decrement the time remaining to assemble the whole packet. */
fragment -> nx_packet_reassembly_time--;
/* Get the next packet fragment. */
previous_fragment = fragment;
fragment = fragment -> nx_packet_queue_next;
}
}
}
#endif /* NX_DISABLE_FRAGMENTATION */