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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_igmp.h"
#include "nx_packet.h"
#include "nx_udp.h"
#ifndef NX_DISABLE_IPV4
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_ipv4_packet_receive PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function receives a packet from the nx_ip_packet_receive. */
/* nx_ip_packet_receive forwards only IPv4 packet to this function. */
/* Here it is either processes it or places it in a deferred */
/* processing queue, depending on the complexity of the packet. */
/* */
/* INPUT */
/* */
/* ip_ptr Pointer to IP control block */
/* packet_ptr Pointer to packet to send */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_ip_checksum_compute Compute IP checksum */
/* _nx_igmp_multicast_check Check for Multicast match */
/* _nx_packet_release Release packet to packet pool */
/* tx_event_flags_set Set events for IP thread */
/* _nx_ip_dispatch_process The routine that examines */
/* other optional headers and */
/* upper layer protocols. */
/* */
/* CALLED BY */
/* */
/* Application I/O Driver */
/* */
/* 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_ipv4_packet_receive(NX_IP *ip_ptr, NX_PACKET *packet_ptr)
{
TX_INTERRUPT_SAVE_AREA
#ifndef NX_DISABLE_PACKET_CHAIN
NX_PACKET *before_last_packet;
NX_PACKET *last_packet;
#endif /* NX_DISABLE_PACKET_CHAIN */
NX_IPV4_HEADER *ip_header_ptr;
ULONG *word_ptr;
ULONG ip_header_length;
ULONG protocol;
ULONG delta;
ULONG val;
ULONG pkt_length;
ULONG checksum;
NX_INTERFACE *if_ptr;
NX_UDP_HEADER *udp_header_ptr;
UINT dest_port;
UINT option_processed;
#if defined(NX_DISABLE_IP_RX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY)
UINT compute_checksum = 1;
#endif /* defined(NX_DISABLE_IP_RX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) */
#ifdef NX_NAT_ENABLE
UINT packet_consumed;
#endif
#ifdef NX_DISABLE_IP_RX_CHECKSUM
compute_checksum = 0;
#endif /* NX_DISABLE_IP_RX_CHECKSUM */
/* It's assumed that the IP link driver has positioned the top pointer in the
packet to the start of the IP address... so that's where we will start. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
ip_header_ptr = (NX_IPV4_HEADER *)packet_ptr -> nx_packet_prepend_ptr;
/* Add debug information. */
NX_PACKET_DEBUG(__FILE__, __LINE__, packet_ptr);
/* If trace is enabled, insert this event into the trace buffer. */
NX_TRACE_IN_LINE_INSERT(NX_TRACE_INTERNAL_IP_RECEIVE, ip_ptr, ip_header_ptr -> nx_ip_header_source_ip, packet_ptr, packet_ptr -> nx_packet_length, NX_TRACE_INTERNAL_EVENTS, 0, 0);
/* Pick up the first word in the IP header. */
val = ip_header_ptr -> nx_ip_header_word_0;
/* Convert to host byte order. */
NX_CHANGE_ULONG_ENDIAN(val);
/* Obtain packet length. */
pkt_length = val & NX_LOWER_16_MASK;
/* Make sure the IP length matches the packet length. Some Ethernet devices
add padding to small packets, which results in a discrepancy between the
packet length and the IP header length. */
if (packet_ptr -> nx_packet_length != pkt_length)
{
/* Determine if the packet length is less than the size reported in the IP header. */
if (packet_ptr -> nx_packet_length < pkt_length)
{
/* Packet is too small! */
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP invalid packet error. */
ip_ptr -> nx_ip_invalid_packets++;
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Invalid packet length, just release it. */
_nx_packet_release(packet_ptr);
/* The function is complete, just return! */
return;
}
/* Calculate the difference in the length. */
delta = packet_ptr -> nx_packet_length - pkt_length;
/* Adjust the packet length. */
packet_ptr -> nx_packet_length = packet_ptr -> nx_packet_length - delta;
/* Adjust the append pointer. */
#ifndef NX_DISABLE_PACKET_CHAIN
/* Loop to process adjustment that spans multiple packets. */
while (delta)
{
/* Determine if the packet is chained (or still chained after the adjustment). */
if (packet_ptr -> nx_packet_last == NX_NULL)
{
/* No, packet is not chained, simply adjust the append pointer in the packet. */
packet_ptr -> nx_packet_append_ptr = packet_ptr -> nx_packet_append_ptr - delta;
/* Break out of the loop, since the adjustment is complete. */
break;
}
/* Pickup the pointer to the last packet. */
last_packet = packet_ptr -> nx_packet_last;
/* Determine if the amount to adjust is less than the payload in the last packet. */
/*lint -e{946} -e{947} suppress pointer subtraction, since it is necessary. */
if (((ULONG)(last_packet -> nx_packet_append_ptr - last_packet -> nx_packet_prepend_ptr)) > delta)
{
/* Yes, simply adjust the append pointer of the last packet in the chain. */
/*lint -e{946} -e{947} suppress pointer subtraction, since it is necessary. */
last_packet -> nx_packet_append_ptr = last_packet -> nx_packet_append_ptr - delta;
/* Get out of the loop, since the adjustment is complete. */
break;
}
else
{
/* Adjust the delta by the amount in the last packet. */
delta = delta - ((ULONG)(last_packet -> nx_packet_append_ptr - last_packet -> nx_packet_prepend_ptr));
/* Find the packet before the last packet. */
before_last_packet = packet_ptr;
while (before_last_packet -> nx_packet_next != last_packet)
{
/* Move to the next packet in the chain. */
before_last_packet = before_last_packet -> nx_packet_next;
}
/* At this point, we need to release the last packet and adjust the other packet
pointers. */
/* Ensure the next packet pointer is NULL in what is now the last packet. */
before_last_packet -> nx_packet_next = NX_NULL;
/* Determine if the packet is still chained. */
if (packet_ptr != before_last_packet)
{
/* Yes, the packet is still chained, setup the last packet pointer. */
packet_ptr -> nx_packet_last = before_last_packet;
}
else
{
/* The packet is no longer chained, set the last packet pointer to NULL. */
packet_ptr -> nx_packet_last = NX_NULL;
}
/* Release the last packet. */
_nx_packet_release(last_packet);
}
}
#else
/* Simply adjust the append pointer in the packet. */
packet_ptr -> nx_packet_append_ptr = packet_ptr -> nx_packet_append_ptr - delta;
#endif /* NX_DISABLE_PACKET_CHAIN */
}
/* Get the incoming interface. */
if_ptr = packet_ptr -> nx_packet_address.nx_packet_interface_ptr;
/* Obtain IP header length. */
ip_header_length = (val & NX_IP_LENGTH_MASK) >> 24;
#ifndef NX_DISABLE_RX_SIZE_CHECKING
/* Check for minimal packet length. The check is done after the endian swapping
since the compiler may possibly be able to optimize the lookup of
"nx_packet_length" and therefore reduce the amount of work performing these
size checks. The endian logic is okay since packets must always have
payloads greater than the IP header in size. */
if ((packet_ptr -> nx_packet_length <= (ip_header_length << 2)) ||
(ip_header_length < NX_IP_NORMAL_LENGTH))
{
/* Packet is too small! */
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP invalid packet error. */
ip_ptr -> nx_ip_invalid_packets++;
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Invalid packet length, just release it. */
_nx_packet_release(packet_ptr);
/* The function is complete, just return! */
return;
}
#endif
#ifdef NX_ENABLE_INTERFACE_CAPABILITY
if (if_ptr -> nx_interface_capability_flag & NX_INTERFACE_CAPABILITY_IPV4_RX_CHECKSUM)
{
compute_checksum = 0;
}
#endif /* NX_ENABLE_INTERFACE_CAPABILITY */
#if defined(NX_DISABLE_IP_RX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY)
if (compute_checksum == 1)
#endif /* defined(NX_DISABLE_IP_RX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) */
{
checksum = _nx_ip_checksum_compute(packet_ptr, NX_IP_VERSION_V4,
/* length is the size of IP header, including options */
(UINT)(ip_header_length << 2),
/* IPv4 header checksum doesn't care src/dest addresses */
NULL, NULL);
checksum = ~checksum & NX_LOWER_16_MASK;
/* Check the checksum again. */
if (checksum)
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP invalid packet error. */
ip_ptr -> nx_ip_invalid_packets++;
/* Increment the IP checksum error. */
ip_ptr -> nx_ip_receive_checksum_errors++;
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Checksum error, just release it. */
_nx_packet_release(packet_ptr);
/* The function is complete, just return! */
return;
}
}
/* IP receive checksum processing is disabled... just check for and remove if
necessary the IP option words. */
/* Endian swapping logic. If NX_LITTLE_ENDIAN is specified, these macros will
swap the endian of the IP header. */
NX_CHANGE_ULONG_ENDIAN(ip_header_ptr -> nx_ip_header_word_0);
NX_CHANGE_ULONG_ENDIAN(ip_header_ptr -> nx_ip_header_word_1);
NX_CHANGE_ULONG_ENDIAN(ip_header_ptr -> nx_ip_header_word_2);
NX_CHANGE_ULONG_ENDIAN(ip_header_ptr -> nx_ip_header_source_ip);
NX_CHANGE_ULONG_ENDIAN(ip_header_ptr -> nx_ip_header_destination_ip);
#ifdef NX_ENABLE_SOURCE_ADDRESS_CHECK
/* Check whether source address is valid. */
/* Section 3.2.1.3, page 30, RFC 1122. */
if (if_ptr -> nx_interface_address_mapping_needed == NX_TRUE)
{
if (((ip_header_ptr -> nx_ip_header_source_ip & ~(if_ptr -> nx_interface_ip_network_mask)) == ~(if_ptr -> nx_interface_ip_network_mask)) ||
(((ip_header_ptr -> nx_ip_header_source_ip & ~(if_ptr -> nx_interface_ip_network_mask)) == 0) &&
(ip_header_ptr -> nx_ip_header_source_ip != 0)) ||
((ip_header_ptr -> nx_ip_header_source_ip & NX_IP_CLASS_D_MASK) == NX_IP_CLASS_D_TYPE))
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP invalid address error. */
ip_ptr -> nx_ip_invalid_receive_address++;
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Toss the IP packet since we don't know what to do with it! */
_nx_packet_release(packet_ptr);
/* Return to caller. */
return;
}
}
#endif /* NX_ENABLE_SOURCE_ADDRESS_CHECK */
/* Determine if there are options in the IP header that make the length greater
than the default length. */
if (ip_header_length > NX_IP_NORMAL_LENGTH)
{
/* Process the IPv4 option. */
option_processed = _nx_ipv4_option_process(ip_ptr, packet_ptr);
/* Check the status. */
if (option_processed == NX_FALSE)
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* IPv4 option error, toss the packet! */
_nx_packet_release(packet_ptr);
/* In all cases, receive processing is finished. Return to caller. */
return;
}
/* Setup a pointer to the last option word. */
word_ptr = ((ULONG *)((VOID *)ip_header_ptr)) + ip_header_length - 1;
/* Remove the option words prior to handling the IP header. */
*word_ptr-- = ip_header_ptr -> nx_ip_header_destination_ip;
*word_ptr-- = ip_header_ptr -> nx_ip_header_source_ip;
*word_ptr-- = ip_header_ptr -> nx_ip_header_word_2;
*word_ptr-- = ip_header_ptr -> nx_ip_header_word_1;
*word_ptr = (ULONG)(((ip_header_ptr -> nx_ip_header_word_0) & (~NX_IP_LENGTH_MASK)) | NX_IP_VERSION);
/* Update the ip_header_ptr and the packet and the packet prepend pointer, ip header pointer and length. */
/*lint -e{929} -e{740} -e{826} suppress cast from pointer to pointer, since it is necessary */
ip_header_ptr = (NX_IPV4_HEADER *)word_ptr;
/*lint -e{928} suppress cast from pointer to pointer, since it is necessary */
packet_ptr -> nx_packet_prepend_ptr = (UCHAR *)word_ptr;
packet_ptr -> nx_packet_ip_header = packet_ptr -> nx_packet_prepend_ptr;
packet_ptr -> nx_packet_length = packet_ptr -> nx_packet_length - ((ip_header_length - NX_IP_NORMAL_LENGTH) * (ULONG)sizeof(ULONG));
}
/* Check if this IP interface has a NAT forwarding service. If so, let NAT get the
packet first and if it is not a packet that should be forwarded by NAT, then
let NetX process the packet in the normal way. */
#ifdef NX_NAT_ENABLE
/* Check if this IP interface has a NAT forwarding service. */
if (ip_ptr -> nx_ip_nat_packet_process)
{
/* Call NAT preprocess hanlder to check if NAT module can process this packet. */
if ((ip_ptr -> nx_ip_nat_packet_process)(ip_ptr, packet_ptr, NX_FALSE) == NX_TRUE)
{
/* NAT router would need to assemble the fragments together first
and then translate prior to forwarding. RFC2663, RFC2766. */
/* Determine if this packet is fragmented. If so, place it on the deferred processing
queue. The input packet will then be processed by an IP system thread. */
if (ip_header_ptr -> nx_ip_header_word_1 & NX_IP_FRAGMENT_MASK)
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP receive fragments count. */
ip_ptr -> nx_ip_total_fragments_received++;
#endif
/* Yes, the incoming IP header is fragmented. Check to see if IP fragmenting
has been enabled. */
if (ip_ptr -> nx_ip_fragment_assembly)
{
/* Yes, fragmenting is available. Place the packet on the incoming
fragment queue. */
/* Disable interrupts. */
TX_DISABLE
/* Determine if the queue is empty. */
if (ip_ptr -> nx_ip_received_fragment_head)
{
/* Reassembly queue is not empty, add this packet to the end of
the queue. */
(ip_ptr -> nx_ip_received_fragment_tail) -> nx_packet_queue_next = packet_ptr;
packet_ptr -> nx_packet_queue_next = NX_NULL;
ip_ptr -> nx_ip_received_fragment_tail = packet_ptr;
}
else
{
/* Reassembly queue is empty. Just setup the head and tail pointers
to point to this packet. */
ip_ptr -> nx_ip_received_fragment_head = packet_ptr;
ip_ptr -> nx_ip_received_fragment_tail = packet_ptr;
packet_ptr -> nx_packet_queue_next = NX_NULL;
}
/* Add debug information. */
NX_PACKET_DEBUG(NX_PACKET_IP_FRAGMENT_QUEUE, __LINE__, packet_ptr);
/* Restore interrupts. */
TX_RESTORE
#ifndef NX_FRAGMENT_IMMEDIATE_ASSEMBLY
/* Wakeup IP helper thread to process the IP fragment re-assembly. */
tx_event_flags_set(&(ip_ptr -> nx_ip_events), NX_IP_UNFRAG_EVENT, TX_OR);
#else
/* Process the IP fragment reassemble. */
(ip_ptr -> nx_ip_fragment_assembly)(ip_ptr);
#endif /* NX_FRAGMENT_IMMEDIATE_ASSEMBLY */
}
else
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Fragmentation has not been enabled, toss the packet! */
_nx_packet_release(packet_ptr);
}
/* In all cases, receive processing is finished. Return to caller. */
return;
}
/* Normal packet, so forward this packet to the NAT handler. If NAT does not 'consume' this
packet, allow NetX to process the packet. */
packet_consumed = (ip_ptr -> nx_ip_nat_packet_process)(ip_ptr, packet_ptr, NX_TRUE);
/* Check to see if the packet has been consumed by NAT. */
if (packet_consumed)
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP packets forwarded counter. */
ip_ptr -> nx_ip_packets_forwarded++;
#endif /* NX_DISABLE_IP_INFO */
return;
}
}
/* (NetX will process all packets that drop through here.) */
}
#endif
/* Determine if the IP datagram is for this IP address or a broadcast IP on this
network. */
if ((ip_header_ptr -> nx_ip_header_destination_ip == if_ptr -> nx_interface_ip_address) ||
/* Check for incoming IP address of zero. Incoming IP address of zero should
be received regardless of our current IP address. */
(ip_header_ptr -> nx_ip_header_destination_ip == 0) ||
/* Check for IP broadcast. */
(((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))) ||
/* Check for limited broadcast. */
(ip_header_ptr -> nx_ip_header_destination_ip == NX_IP_LIMITED_BROADCAST) ||
/* Check for loopback address. */
((ip_header_ptr -> nx_ip_header_destination_ip >= NX_IP_LOOPBACK_FIRST) &&
(ip_header_ptr -> nx_ip_header_destination_ip <= NX_IP_LOOPBACK_LAST)) ||
/* Check for valid Multicast address. */
(_nx_igmp_multicast_check(ip_ptr, ip_header_ptr -> nx_ip_header_destination_ip, if_ptr)))
{
/* Determine if this packet is fragmented. If so, place it on the deferred processing
queue. The input packet will then be processed by an IP system thread. */
if (ip_header_ptr -> nx_ip_header_word_1 & NX_IP_FRAGMENT_MASK)
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP receive fragments count. */
ip_ptr -> nx_ip_total_fragments_received++;
#endif
/* Yes, the incoming IP header is fragmented. Check to see if IP fragmenting
has been enabled. */
#ifdef NX_ENABLE_LOW_WATERMARK
if (ip_ptr -> nx_ip_fragment_assembly &&
(packet_ptr -> nx_packet_pool_owner -> nx_packet_pool_available >=
packet_ptr -> nx_packet_pool_owner -> nx_packet_pool_low_watermark))
#else
if (ip_ptr -> nx_ip_fragment_assembly)
#endif
{
/* Yes, fragmenting is available. Place the packet on the incoming
fragment queue. */
/* Disable interrupts. */
TX_DISABLE
/* Determine if the queue is empty. */
if (ip_ptr -> nx_ip_received_fragment_head)
{
/* Reassembly queue is not empty, add this packet to the end of
the queue. */
(ip_ptr -> nx_ip_received_fragment_tail) -> nx_packet_queue_next = packet_ptr;
packet_ptr -> nx_packet_queue_next = NX_NULL;
ip_ptr -> nx_ip_received_fragment_tail = packet_ptr;
}
else
{
/* Reassembly queue is empty. Just setup the head and tail pointers
to point to this packet. */
ip_ptr -> nx_ip_received_fragment_head = packet_ptr;
ip_ptr -> nx_ip_received_fragment_tail = packet_ptr;
packet_ptr -> nx_packet_queue_next = NX_NULL;
}
/* Add debug information. */
NX_PACKET_DEBUG(NX_PACKET_IP_FRAGMENT_QUEUE, __LINE__, packet_ptr);
/* Restore interrupts. */
TX_RESTORE
#ifndef NX_FRAGMENT_IMMEDIATE_ASSEMBLY
/* Wakeup IP helper thread to process the IP fragment re-assembly. */
tx_event_flags_set(&(ip_ptr -> nx_ip_events), NX_IP_UNFRAG_EVENT, TX_OR);
#else
/* Process the IP fragment reassemble. */
(ip_ptr -> nx_ip_fragment_assembly)(ip_ptr);
#endif /* NX_FRAGMENT_IMMEDIATE_ASSEMBLY */
}
else
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Fragmentation has not been enabled, toss the packet! */
_nx_packet_release(packet_ptr);
}
/* In all cases, receive processing is finished. Return to caller. */
return;
}
/* Determine what protocol the current IP datagram is. */
protocol = (ip_header_ptr -> nx_ip_header_word_2 >> 16) & 0xFF;
/* Remove the IP header from the packet. */
packet_ptr -> nx_packet_prepend_ptr = packet_ptr -> nx_packet_prepend_ptr + sizeof(NX_IPV4_HEADER);
/* Adjust the length. */
packet_ptr -> nx_packet_length = packet_ptr -> nx_packet_length - (ULONG)sizeof(NX_IPV4_HEADER);
#ifndef NX_DISABLE_IP_INFO
/* Increment the number of packets delivered. */
ip_ptr -> nx_ip_total_packets_delivered++;
/* Increment the IP packet bytes received (not including the header). */
ip_ptr -> nx_ip_total_bytes_received += packet_ptr -> nx_packet_length;
#endif
if (_nx_ip_dispatch_process(ip_ptr, packet_ptr, (UINT)protocol))
{
_nx_packet_release(packet_ptr);
}
}
/* Try to receive the DHCP message before release this packet.
NetX should receive the unicast DHCP message when interface IP address is zero. */
/* Check if this IP interface has IP address. */
else if (if_ptr -> nx_interface_ip_address == 0)
{
/* Determine what protocol the current IP datagram is. */
protocol = ip_header_ptr -> nx_ip_header_word_2 & NX_IP_PROTOCOL_MASK;
/* Check if this packet is UDP message. */
if (protocol == NX_IP_UDP)
{
/* Remove the IP header from the packet. */
packet_ptr -> nx_packet_prepend_ptr = packet_ptr -> nx_packet_prepend_ptr + sizeof(NX_IPV4_HEADER);
/* Adjust the length. */
packet_ptr -> nx_packet_length = packet_ptr -> nx_packet_length - (ULONG)sizeof(NX_IPV4_HEADER);
#ifndef NX_DISABLE_IP_INFO
/* Increment the number of packets delivered. */
ip_ptr -> nx_ip_total_packets_delivered++;
/* Increment the IP packet bytes received (not including the header). */
ip_ptr -> nx_ip_total_bytes_received += packet_ptr -> nx_packet_length;
#endif
/* Pickup the pointer to the head of the UDP packet. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
udp_header_ptr = (NX_UDP_HEADER *)packet_ptr -> nx_packet_prepend_ptr;
/* Endian swapping logic. If NX_LITTLE_ENDIAN is specified, these macros will
swap the endian of the UDP header. */
NX_CHANGE_ULONG_ENDIAN(udp_header_ptr -> nx_udp_header_word_0);
/* Pickup the destination UDP port. */
dest_port = (UINT)(udp_header_ptr -> nx_udp_header_word_0 & NX_LOWER_16_MASK);
/* Endian swapping logic. If NX_LITTLE_ENDIAN is specified, these macros will
swap the endian of the UDP header. */
NX_CHANGE_ULONG_ENDIAN(udp_header_ptr -> nx_udp_header_word_0);
/* Check if this packet is DHCP message. */
if (dest_port == 68)
{
if (ip_ptr -> nx_ip_udp_packet_receive)
{
/* Yes, dispatch it to the appropriate UDP handler if present. */
(ip_ptr -> nx_ip_udp_packet_receive)(ip_ptr, packet_ptr);
return;
}
}
}
#ifndef NX_DISABLE_IP_INFO
/* Decrement the number of packets delivered. */
ip_ptr -> nx_ip_total_packets_delivered--;
/* Decrement the IP packet bytes received (not including the header). */
ip_ptr -> nx_ip_total_bytes_received -= packet_ptr -> nx_packet_length;
/* Increment the IP invalid address error. */
ip_ptr -> nx_ip_invalid_receive_address++;
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Toss the IP packet since we don't know what to do with it! */
_nx_packet_release(packet_ptr);
/* Return to caller. */
return;
}
else if (ip_ptr -> nx_ip_forward_packet_process)
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP packets forwarded counter. */
ip_ptr -> nx_ip_packets_forwarded++;
#endif
/* The packet is not for this IP instance so call the
forward IP packet processing routine. */
(ip_ptr -> nx_ip_forward_packet_process)(ip_ptr, packet_ptr);
}
else
{
#ifndef NX_DISABLE_IP_INFO
/* Increment the IP invalid address error. */
ip_ptr -> nx_ip_invalid_receive_address++;
/* Increment the IP receive packets dropped count. */
ip_ptr -> nx_ip_receive_packets_dropped++;
#endif
/* Toss the IP packet since we don't know what to do with it! */
_nx_packet_release(packet_ptr);
/* Return to caller. */
return;
}
}
#endif /* !NX_DISABLE_IPV4 */