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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 Control Message Protocol (ICMPv4) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SOURCE_CODE
/* Include necessary system files. */
#include "nx_api.h"
#include "nx_packet.h"
#include "nx_ip.h"
#include "nx_icmp.h"
#ifdef NX_IPSEC_ENABLE
#include "nx_ipsec.h"
#endif /* NX_IPSEC_ENABLE */
#if !defined(NX_DISABLE_IPV4) && !defined(NX_DISABLE_ICMPV4_ERROR_MESSAGE)
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_icmpv4_send_error_message PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function is called by various IPv4 components to send an */
/* error message when necessary. */
/* */
/* INPUT */
/* */
/* ip_ptr IP stack instance */
/* offending_packet The packet that caused the */
/* error. */
/* word1 ICMPv4 error message header */
/* field, progarmmed by */
/* the caller. */
/* error_pointer Pointer to the byte that */
/* caused the error */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_ip_checksum_compute Computer ICMP checksum */
/* _nx_ip_packet_send Send ICMP packet out */
/* _nx_packet_allocate Packet allocate */
/* _nx_packet_release Release packet back to pool */
/* _nx_ip_route_find Find outgoing interface for */
/* sending packet */
/* */
/* CALLED BY */
/* */
/* */
/* 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_icmpv4_send_error_message(NX_IP *ip_ptr, NX_PACKET *offending_packet,
ULONG word1, ULONG error_pointer)
{
NX_PACKET *pkt_ptr;
USHORT checksum;
#if defined(NX_DISABLE_ICMPV4_TX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) || defined(NX_IPSEC_ENABLE)
UINT compute_checksum = 1;
#endif /* defined(NX_DISABLE_ICMPV4_TX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) || defined(NX_IPSEC_ENABLE) */
NX_ICMPV4_ERROR *icmpv4_error;
NX_IPV4_HEADER *ip_header_ptr;
UINT ip_header_size;
UINT bytes_to_copy, i;
ULONG src_ip;
ULONG next_hop_address = NX_NULL;
ULONG *src_packet, *dest_packet;
NX_INTERFACE *if_ptr;
#ifdef NX_IPSEC_ENABLE
VOID *sa = NX_NULL;
UINT ret = 0;
ULONG data_offset;
NXD_ADDRESS src_addr;
NXD_ADDRESS dest_addr;
#endif /* NX_IPSEC_ENABLE */
/* Add debug information. */
NX_PACKET_DEBUG(__FILE__, __LINE__, offending_packet);
/* Do not send ICMPv4 error message if ICMPv4 is not enabled. */
if (ip_ptr -> nx_ip_icmpv4_packet_process == NX_NULL)
{
return;
}
/* Find out the source and destination IP addresses of the offending packet. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
ip_header_ptr = (NX_IPV4_HEADER *)(offending_packet -> nx_packet_ip_header);
src_ip = ip_header_ptr -> nx_ip_header_source_ip;
/* Get the incoming interface. */
if_ptr = offending_packet -> nx_packet_address.nx_packet_interface_ptr;
/* An ICMP error message MUST NOT be sent as the result of receiving:
RFC1122, Section3.2.2, Page39. */
/* A datagram destined to an IP broadcast or IP multicast address. */
if ((ip_header_ptr -> nx_ip_header_destination_ip == NX_IP_LIMITED_BROADCAST) ||
((ip_header_ptr -> nx_ip_header_destination_ip & NX_IP_CLASS_D_MASK) == NX_IP_CLASS_D_TYPE))
{
return;
}
/* A datagram sent as a link-layer broadcast. */
if (((ip_header_ptr -> nx_ip_header_destination_ip & if_ptr -> nx_interface_ip_network_mask) ==
if_ptr -> nx_interface_ip_network) &&
((ip_header_ptr -> nx_ip_header_destination_ip & ~(if_ptr -> nx_interface_ip_network_mask)) ==
~(if_ptr -> nx_interface_ip_network_mask)))
{
return;
}
/* A non-initial fragment. */
if (ip_header_ptr -> nx_ip_header_word_1 & NX_IP_OFFSET_MASK)
{
return;
}
/* A datagram whose source address does not define a single host,
e.g., a zero address, a loopback address, a broadcast address,
a multicast address, or a Class E address. */
if ((ip_header_ptr -> nx_ip_header_source_ip == 0) ||
((ip_header_ptr -> nx_ip_header_source_ip >= NX_IP_LOOPBACK_FIRST) &&
(ip_header_ptr -> nx_ip_header_source_ip <= NX_IP_LOOPBACK_LAST)) ||
(ip_header_ptr -> nx_ip_header_source_ip == NX_IP_LIMITED_BROADCAST) ||
((ip_header_ptr -> nx_ip_header_source_ip & NX_IP_CLASS_D_MASK) == NX_IP_CLASS_D_TYPE))
{
return;
}
/* Allocate a packet to build the ICMPv4 error message in. */
if (_nx_packet_allocate(ip_ptr -> nx_ip_default_packet_pool, &pkt_ptr, NX_IPv4_ICMP_PACKET, NX_NO_WAIT))
{
/* Error getting packet, so just get out! */
return;
}
/* Add debug information. */
NX_PACKET_DEBUG(__FILE__, __LINE__, pkt_ptr);
/* Mark the packet as IPv4. */
/*lint -e{644} suppress variable might not be initialized, since "pkt_ptr" was initialized in _nx_packet_allocate. */
pkt_ptr -> nx_packet_ip_version = NX_IP_VERSION_V4;
/* Size of the message is ICMPv4 */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
icmpv4_error = (NX_ICMPV4_ERROR *)(pkt_ptr -> nx_packet_prepend_ptr);
icmpv4_error -> nx_icmpv4_error_header.nx_icmpv4_header_type = (UCHAR)((word1 >> 24) & 0xFF);
icmpv4_error -> nx_icmpv4_error_header.nx_icmpv4_header_code = (UCHAR)((word1 >> 16) & 0xFF);
icmpv4_error -> nx_icmpv4_error_header.nx_icmpv4_header_checksum = 0;
icmpv4_error -> nx_icmpv4_error_pointer = (error_pointer << 24);
/* Change to network byte order. */
NX_CHANGE_ULONG_ENDIAN(icmpv4_error -> nx_icmpv4_error_pointer);
/* IP Header + 64 bits (64 bits = 2 ULONGs) of Data Datagram. */
ip_header_size = ((ip_header_ptr -> nx_ip_header_word_0 & 0x0F000000) >> 24);
bytes_to_copy = (UINT)((ip_header_size + 2) * sizeof(ULONG));
/* Set the packet length and pointers. The length will be increased to include
the IPv4 header in the IP send function. The Prepend function will be similarly
updated in the IP send function. */
pkt_ptr -> nx_packet_length = bytes_to_copy + (ULONG)sizeof(NX_ICMPV4_ERROR);
pkt_ptr -> nx_packet_append_ptr = pkt_ptr -> nx_packet_prepend_ptr + pkt_ptr -> nx_packet_length;
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
src_packet = (ULONG *)(offending_packet -> nx_packet_ip_header);
/*lint -e{923} suppress cast between pointer and ULONG, since it is necessary */
dest_packet = (ULONG *)NX_UCHAR_POINTER_ADD(icmpv4_error, sizeof(NX_ICMPV4_ERROR));
/* Endian swap the incoming IPv4 normal header to network byte order. */
for (i = 0; i < NX_IP_NORMAL_LENGTH; i++)
{
NX_CHANGE_ULONG_ENDIAN(*src_packet);
src_packet++;
}
/* Reset the packet pointer to the received packet IP header. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
src_packet = (ULONG *)(offending_packet -> nx_packet_ip_header);
/* Copy the data from the received packet to the ICMPv4 error packet. */
for (; bytes_to_copy > 0; bytes_to_copy -= 4)
{
*dest_packet++ = *src_packet++;
}
/* Get the IP header pointer. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
src_packet = (ULONG *)(offending_packet -> nx_packet_ip_header);
/* Endian swap the IPv4 normal header back to host byte order. */
for (i = 0; i < NX_IP_NORMAL_LENGTH; i++)
{
NX_CHANGE_ULONG_ENDIAN(*src_packet);
src_packet++;
}
/* Use the corresponding interface address as sender's address. */
pkt_ptr -> nx_packet_address.nx_packet_interface_ptr = offending_packet -> nx_packet_address.nx_packet_interface_ptr;
/* Figure out the best interface to send the ICMP packet on. */
_nx_ip_route_find(ip_ptr, src_ip,
&pkt_ptr -> nx_packet_address.nx_packet_interface_ptr,
&next_hop_address);
#ifdef NX_IPSEC_ENABLE
/* Check for possible SA match. */
if (ip_ptr -> nx_ip_packet_egress_sa_lookup != NX_NULL) /* IPsec is enabled. */
{
/* Set up IP address. */
src_addr.nxd_ip_version = NX_IP_VERSION_V4;
src_addr.nxd_ip_address.v4 = pkt_ptr -> nx_packet_address.nx_packet_interface_ptr -> nx_interface_ip_address;
dest_addr.nxd_ip_version = NX_IP_VERSION_V4;
dest_addr.nxd_ip_address.v4 = src_ip;
/* If the SA has not been set. */
ret = ip_ptr -> nx_ip_packet_egress_sa_lookup(ip_ptr, /* IP ptr */
&src_addr, /* src_addr */
&dest_addr, /* dest_addr */
NX_PROTOCOL_ICMP, /* protocol */
0, /* src_port */
0, /* dest_port */
&data_offset, &sa,
((word1 >> 16) & 0xFFFF));
if (ret == NX_IPSEC_TRAFFIC_BYPASS)
{
sa = NX_NULL;
data_offset = 0;
}
else if (ret == NX_IPSEC_TRAFFIC_DROP || ret == NX_IPSEC_TRAFFIC_PENDING_IKEV2)
{
/* IPSec SA disallows this packet. Drop the packet and return. */
_nx_packet_release(pkt_ptr);
return;
}
}
pkt_ptr -> nx_packet_ipsec_sa_ptr = sa;
#endif /* NX_IPSEC_ENABLE */
#ifdef NX_DISABLE_ICMPV4_TX_CHECKSUM
compute_checksum = 0;
#endif /* NX_DISABLE_ICMPV4_TX_CHECKSUM */
#ifdef NX_ENABLE_INTERFACE_CAPABILITY
if (pkt_ptr -> nx_packet_address.nx_packet_interface_ptr -> nx_interface_capability_flag & NX_INTERFACE_CAPABILITY_ICMPV4_TX_CHECKSUM)
{
compute_checksum = 0;
}
#endif /* NX_ENABLE_INTERFACE_CAPABILITY */
#ifdef NX_IPSEC_ENABLE
if ((sa != NX_NULL) && (((NX_IPSEC_SA *)sa) -> nx_ipsec_sa_encryption_method != NX_CRYPTO_NONE))
{
compute_checksum = 1;
}
#endif /* NX_IPSEC_ENABLE */
#if defined(NX_DISABLE_ICMPV4_TX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) || defined(NX_IPSEC_ENABLE)
if (compute_checksum)
#endif /* defined(NX_DISABLE_ICMPV4_TX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) || defined(NX_IPSEC_ENABLE) */
{
/* Compute the checksum of the ICMP packet. */
checksum = _nx_ip_checksum_compute(pkt_ptr, NX_IP_ICMP,
(UINT)pkt_ptr -> nx_packet_length,
/* ICMPV4 checksum does not include
src/dest addresses */
NX_NULL, NX_NULL);
icmpv4_error -> nx_icmpv4_error_header.nx_icmpv4_header_checksum = (USHORT)(~checksum);
/* Swap to network byte order. */
NX_CHANGE_USHORT_ENDIAN(icmpv4_error -> nx_icmpv4_error_header.nx_icmpv4_header_checksum);
}
#ifdef NX_ENABLE_INTERFACE_CAPABILITY
else
{
pkt_ptr -> nx_packet_interface_capability_flag |= NX_INTERFACE_CAPABILITY_ICMPV4_TX_CHECKSUM;
}
#endif /* NX_ENABLE_INTERFACE_CAPABILITY */
/* Send the ICMP packet to the IP component. The time to live is set to 255. */
/*lint -e{644} suppress variable might not be initialized, since "next_hop_address" was initialized in _nx_ip_route_find. */
_nx_ip_packet_send(ip_ptr, pkt_ptr, src_ip,
NX_IP_NORMAL, 255, NX_IP_ICMP, NX_FRAGMENT_OKAY, next_hop_address);
return;
}
#endif /* !NX_DISABLE_IPV4 && !NX_DISABLE_ICMPV4_ERROR_MESSAGE */