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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"
#ifndef NX_DISABLE_IPV4
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_ip_route_find PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function finds an outgoing interface and the next hop address */
/* for a given destination address. The caller may also set desired */
/* interface information in the ip_interface_ptr input. For multicast*/
/* or limited broadcast, this routine looks for the first enabled */
/* interface (link up) starting with the primary interface if */
/* a hint was not set by the caller. For directed broadcast or */
/* unicast destinations, the hint is ignored and the proper outgoing */
/* interface is selected. */
/* */
/* INPUT */
/* */
/* ip_ptr IN Pointer to IP instance */
/* destination_address IN Destination address */
/* ip_interface_ptr OUT Interface to use, must point */
/* to valid storage space. */
/* next_hop_address OUT IP address for the next hop, */
/* must point to valid storage */
/* space. */
/* */
/* OUTPUT */
/* */
/* NX_SUCCESS Operation was successful */
/* NX_IP_ADDRESS_ERROR No suitable interface found */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_arp_dynamic_entry_set.c ARP entry set */
/* _nx_icmp_ping Transmit ICMP echo request */
/* _nx_ip_packet_send IP packet transmit */
/* _nx_tcp_client_socket_connect TCP Client socket connection */
/* _nx_udp_socket_send UDP packet send */
/* */
/* NOTE: */
/* */
/* None */
/* */
/* 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 */
/* */
/**************************************************************************/
ULONG _nx_ip_route_find(NX_IP *ip_ptr, ULONG destination_address, NX_INTERFACE **ip_interface_ptr, ULONG *next_hop_address)
{
NX_INTERFACE *interface_ptr;
ULONG i;
/* Initialize the next hop address. */
*next_hop_address = 0;
/* Determine if the destination_address is multicast or directed broadcast. */
if (((destination_address & NX_IP_CLASS_D_MASK) == NX_IP_CLASS_D_TYPE) ||
(destination_address == NX_IP_LIMITED_BROADCAST))
{
*next_hop_address = destination_address;
/* If the caller did not set the ip_interface value, find a link enabled
interface, starting with the primary interface, for transmission. */
if (*ip_interface_ptr == NX_NULL)
{
/* Find an interface whose link is up. */
for (i = 0; i < NX_MAX_PHYSICAL_INTERFACES; i++)
{
if (ip_ptr -> nx_ip_interface[i].nx_interface_link_up)
{
*ip_interface_ptr = &(ip_ptr -> nx_ip_interface[i]);
return(NX_SUCCESS);
}
}
}
/* If the specified interface is up, return success. */
else if ((*ip_interface_ptr) -> nx_interface_link_up)
{
return(NX_SUCCESS);
}
/* No available interface. */
return(NX_IP_ADDRESS_ERROR);
}
/* Search through the interfaces associated with the IP instance,
check if the the destination address is one of the local interface addresses. */
for (i = 0; i < NX_MAX_PHYSICAL_INTERFACES; i++)
{
/* Use a local variable for convenience. */
interface_ptr = &(ip_ptr -> nx_ip_interface[i]);
/* Check for a valid interface that maps onto the same network domain as the destination address. */
if ((interface_ptr -> nx_interface_valid) &&
(interface_ptr -> nx_interface_link_up) &&
(interface_ptr -> nx_interface_ip_address == destination_address) &&
((*ip_interface_ptr == NX_NULL) ||
(*ip_interface_ptr == interface_ptr)))
{
/* Yes, use the entry information for interface and next hop. */
*ip_interface_ptr = interface_ptr;
*next_hop_address = destination_address;
return(NX_SUCCESS);
}
}
#ifdef NX_ENABLE_IP_STATIC_ROUTING
/* Search through the routing table for a suitable interface. */
for (i = 0; i < ip_ptr -> nx_ip_routing_table_entry_count; i++)
{
/* Get the interface. */
interface_ptr = ip_ptr -> nx_ip_routing_table[i].nx_ip_routing_entry_ip_interface;
/* Skip interface that is not up. */
if (interface_ptr -> nx_interface_link_up == NX_FALSE)
{
continue;
}
/* Does this table entry match the destination table network domain?*/
if (ip_ptr -> nx_ip_routing_table[i].nx_ip_routing_dest_ip ==
(destination_address & ip_ptr -> nx_ip_routing_table[i].nx_ip_routing_net_mask))
{
/* Yes, is next hop address still reachable? */
if (interface_ptr -> nx_interface_ip_network !=
(ip_ptr -> nx_ip_routing_table[i].nx_ip_routing_next_hop_address &
interface_ptr -> nx_interface_ip_network_mask))
{
continue;
}
/* Use the entry information for interface and next hop. */
if (*ip_interface_ptr == NX_NULL)
{
*ip_interface_ptr = interface_ptr;
}
else if (*ip_interface_ptr != interface_ptr)
{
continue;
}
*next_hop_address = ip_ptr -> nx_ip_routing_table[i].nx_ip_routing_next_hop_address;
return(NX_SUCCESS);
}
}
#endif /* NX_ENABLE_IP_STATIC_ROUTING */
/* Search through the interfaces associated with the IP instance,
check if the entry exists. */
for (i = 0; i < NX_MAX_IP_INTERFACES; i++)
{
/* Use a local variable for convenience. */
interface_ptr = &(ip_ptr -> nx_ip_interface[i]);
/* Check for a valid interface that maps onto the same network domain as the destination address. */
if ((interface_ptr -> nx_interface_valid) &&
(interface_ptr -> nx_interface_link_up) &&
((interface_ptr -> nx_interface_ip_network_mask & destination_address) == interface_ptr -> nx_interface_ip_network))
{
/* Yes, use the entry information for interface and next hop. */
if (*ip_interface_ptr == NX_NULL)
{
*ip_interface_ptr = interface_ptr;
}
/* Match loopback interface. */
/* Suppress constant value, since "NX_MAX_IP_INTERFACES" can be redefined. */
#if (NX_MAX_IP_INTERFACES == (NX_MAX_PHYSICAL_INTERFACES + 1))
else if (i == NX_MAX_PHYSICAL_INTERFACES)
{
*ip_interface_ptr = interface_ptr;
}
#endif
else if (*ip_interface_ptr != interface_ptr)
{
continue;
}
*next_hop_address = destination_address;
return(NX_SUCCESS);
}
}
/* Search the interfaces for IPv4 Link-Local Address according to RFC3927, section2.6. */
/* Determine if destination addrss is link-local address(169.254/16 Hexadecimal:0xA9FE0000). */
if ((destination_address & 0xFFFF0000) == 0xA9FE0000)
{
/* Yes, check if the interface is set. */
if (*ip_interface_ptr)
{
/* Determine if the interface is valid. */
if (((*ip_interface_ptr) -> nx_interface_valid) &&
((*ip_interface_ptr) -> nx_interface_link_up))
{
/* Set the next hop address. */
*next_hop_address = destination_address;
return(NX_SUCCESS);
}
}
else
{
/* Search through the interfaces associated with the IP instance, set the inteface as first valid interface. */
for (i = 0; i < NX_MAX_IP_INTERFACES; i++)
{
/* Check for a valid interface that the address is link-local address. */
if ((ip_ptr -> nx_ip_interface[i].nx_interface_valid) &&
(ip_ptr -> nx_ip_interface[i].nx_interface_link_up))
{
/* Yes, use the entry information for interface and next hop. */
*ip_interface_ptr = &(ip_ptr -> nx_ip_interface[i]);
*next_hop_address = destination_address;
return(NX_SUCCESS);
}
}
}
}
/* Does the IP instance have a gateway? */
if ((ip_ptr -> nx_ip_gateway_address) &&
(ip_ptr -> nx_ip_gateway_interface) &&
(ip_ptr -> nx_ip_gateway_interface -> nx_interface_link_up))
{
/* Get the interface. */
interface_ptr = ip_ptr -> nx_ip_gateway_interface;
/* Yes, is gateway address still reachable? */
if (interface_ptr -> nx_interface_ip_network !=
(ip_ptr -> nx_ip_gateway_address &
interface_ptr -> nx_interface_ip_network_mask))
{
return(NX_IP_ADDRESS_ERROR);
}
/* Use the gateway as default. */
if (*ip_interface_ptr == NX_NULL)
{
*ip_interface_ptr = interface_ptr;
}
else if (*ip_interface_ptr != interface_ptr)
{
return(NX_IP_ADDRESS_ERROR);
}
*next_hop_address = ip_ptr -> nx_ip_gateway_address;
return(NX_SUCCESS);
}
/* Determine if source addrss is link-local address(169.254/16 Hexadecimal:0xA9FE0000). */
if (*ip_interface_ptr)
{
/* Determine if the interface is valid and the address of interface is link-local address. */
if (((*ip_interface_ptr) -> nx_interface_valid) &&
((*ip_interface_ptr) -> nx_interface_link_up) &&
(((*ip_interface_ptr) -> nx_interface_ip_address & 0xFFFF0000) == 0xA9FE0000))
{
/* Set the next hop address. */
*next_hop_address = destination_address;
return(NX_SUCCESS);
}
}
else
{
/* Search through the interfaces associated with the IP instance,
check if interface is valid and the address of interface is link-local address. */
for (i = 0; i < NX_MAX_IP_INTERFACES; i++)
{
/* Use a local variable for convenience. */
interface_ptr = &(ip_ptr -> nx_ip_interface[i]);
/* Check for a valid interface that the address is link-local address. */
if ((interface_ptr -> nx_interface_valid) &&
(interface_ptr -> nx_interface_link_up) &&
((interface_ptr -> nx_interface_ip_address & 0xFFFF0000) == 0xA9FE0000))
{
/* Yes, use the entry information for interface and next hop. */
*ip_interface_ptr = interface_ptr;
*next_hop_address = destination_address;
return(NX_SUCCESS);
}
}
}
/* Cannot find a proper way to transmit this packet.
Return the error status. */
return(NX_IP_ADDRESS_ERROR);
}
#endif /* NX_DISABLE_IPV4 */