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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 Group Management Protocol (IGMP) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SOURCE_CODE
/* Include necessary system files. */
#include "nx_api.h"
#include "nx_packet.h"
#include "nx_igmp.h"
#ifndef NX_DISABLE_IPV4
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_igmp_packet_process PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function handles reception of IGMP packets. There are two types*/
/* of IGMP packets. Routers will send IGMP query messages and other */
/* send responses intended for the router but will be seen by all other */
/* hosts belonging to the same multicast group. In the latter case the */
/* other hosts will cancel their own response for the same multicast */
/* group. */
/* */
/* INPUT */
/* */
/* ip_ptr IP instance pointer */
/* packet_ptr IGMP packet pointer */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_packet_release Release IGMP packet */
/* tx_time_get Get current time */
/* */
/* CALLED BY */
/* */
/* _nx_igmp_packet_receive IGMP packet receive */
/* _nx_igmp_queue_process IGMP queue processing */
/* */
/* 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_igmp_packet_process(NX_IP *ip_ptr, NX_PACKET *packet_ptr)
{
UINT i;
ULONG update_time;
NX_IGMP_HEADER *header_ptr;
USHORT max_update_time;
ULONG checksum;
ULONG length;
UCHAR *word_ptr;
NX_PACKET *current_packet;
ULONG long_temp;
USHORT short_temp;
/* Add debug information. */
NX_PACKET_DEBUG(__FILE__, __LINE__, packet_ptr);
/* Setup a pointer to the IGMP packet header. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
header_ptr = (NX_IGMP_HEADER *)packet_ptr -> nx_packet_prepend_ptr;
#ifdef NX_ENABLE_INTERFACE_CAPABILITY
if (!(packet_ptr -> nx_packet_address.nx_packet_interface_ptr -> nx_interface_capability_flag & NX_INTERFACE_CAPABILITY_IGMP_RX_CHECKSUM))
#endif /* FEATURE_LINK_CAPABILITY */
{
/* First verify the checksum is correct. */
/* Setup the length of the packet checksum. */
length = packet_ptr -> nx_packet_length;
/* Determine if we need to add a padding byte. */
if (((length / sizeof(USHORT)) * sizeof(USHORT)) != length)
{
/* We have single byte alignment and we need two byte alignment. */
length++;
#ifndef NX_DISABLE_PACKET_CHAIN
/* Determine if there is a last packet pointer. */
if (packet_ptr -> nx_packet_last)
{
/* Multi-packet message, add a zero byte at the end. */
*((packet_ptr -> nx_packet_last) -> nx_packet_append_ptr) = 0;
}
else
{
#endif
/* Write a zero byte at the end of the first and only packet. */
*(packet_ptr -> nx_packet_append_ptr) = 0;
#ifndef NX_DISABLE_PACKET_CHAIN
}
#endif
}
/* Setup the pointer to the start of the packet. */
word_ptr = (UCHAR *)packet_ptr -> nx_packet_prepend_ptr;
/* Initialize the current packet to the input packet pointer. */
current_packet = packet_ptr;
checksum = 0;
/* Loop to calculate the checksum over the entire packet. */
while (length)
{
/* Determine if there is at least one ULONG left. */
if ((UINT)(current_packet -> nx_packet_append_ptr - word_ptr) >= sizeof(ULONG))
{
/* Pickup a whole ULONG. */
long_temp = *((ULONG *)word_ptr);
/* Add upper 16-bits into checksum. */
checksum = checksum + (long_temp >> NX_SHIFT_BY_16);
/* Check for carry bits. */
if (checksum & NX_CARRY_BIT)
{
checksum = (checksum & NX_LOWER_16_MASK) + 1;
}
/* Add lower 16-bits into checksum. */
checksum = checksum + (long_temp & NX_LOWER_16_MASK);
/* Check for carry bits. */
if (checksum & NX_CARRY_BIT)
{
checksum = (checksum & NX_LOWER_16_MASK) + 1;
}
/* Move the word pointer and decrease the length. */
word_ptr = word_ptr + sizeof(ULONG);
length = length - (ULONG)sizeof(ULONG);
}
else
{
/* Pickup the 16-bit word. */
short_temp = *((USHORT *)word_ptr);
/* Add next 16-bit word into checksum. */
checksum = checksum + short_temp;
/* Check for carry bits. */
if (checksum & NX_CARRY_BIT)
{
checksum = (checksum & NX_LOWER_16_MASK) + 1;
}
/* Move the word pointer and decrease the length. */
word_ptr = word_ptr + sizeof(USHORT);
length = length - (ULONG)sizeof(USHORT);
}
#ifndef NX_DISABLE_PACKET_CHAIN
/* Determine if we are at the end of the current packet. */
if ((word_ptr >= (UCHAR *)current_packet -> nx_packet_append_ptr) &&
(current_packet -> nx_packet_next))
{
/* We have crossed the packet boundary. Move to the next packet
structure. */
current_packet = current_packet -> nx_packet_next;
/* Setup the new word pointer. */
word_ptr = (UCHAR *)current_packet -> nx_packet_prepend_ptr;
}
#endif
}
checksum = ~checksum & NX_LOWER_16_MASK;
/* Determine if the checksum is valid. */
if (checksum)
{
/* It is not. By RFC requirements we should not accept this packet. */
#ifndef NX_DISABLE_IGMP_INFO
/* Increment the IGMP invalid packet error. */
ip_ptr -> nx_ip_igmp_invalid_packets++;
/* Increment the IGMP checksum error count. */
ip_ptr -> nx_ip_igmp_checksum_errors++;
#endif /* NX_DISABLE_IGMP_INFO */
/* Toss this IGMP packet out. */
_nx_packet_release(packet_ptr);
return;
}
}
/* Swap the IGMP headers to host byte order. */
NX_CHANGE_ULONG_ENDIAN(header_ptr -> nx_igmp_header_word_0);
NX_CHANGE_ULONG_ENDIAN(header_ptr -> nx_igmp_header_word_1);
/* If trace is enabled, insert this event into the trace buffer. */
NX_TRACE_IN_LINE_INSERT(NX_TRACE_INTERNAL_IGMP_RECEIVE, ip_ptr, *(((ULONG *)packet_ptr -> nx_packet_prepend_ptr) - 2), packet_ptr, header_ptr -> nx_igmp_header_word_0, NX_TRACE_INTERNAL_EVENTS, 0, 0);
/* Determine the type of IGMP message received. Note that an IGMPv1 host will respond
to an IGMPv2 general query but not process the maximum response time field. */
if ((header_ptr -> nx_igmp_header_word_0 & NX_IGMP_TYPE_MASK) == NX_IGMP_ROUTER_QUERY_TYPE)
{
#ifndef NX_DISABLE_IGMP_INFO
/* Increment the IGMP queries received count. */
ip_ptr -> nx_ip_igmp_queries_received++;
#endif
/* Set the max response time recommended by RFC 1112 set by host in seconds. In a
IGMPv2 network, the router may set a different max time in its IGMP membership queries. */
max_update_time = NX_IGMP_MAX_UPDATE_TIME;
#ifndef NX_DISABLE_IGMPV2
/* Determine the IGMP version the sender (router) is using. */
/* Is the max response time non zero? */
if ((header_ptr -> nx_igmp_header_word_0 & NX_IGMP_MAX_RESP_TIME_MASK) != NX_NULL)
{
/* Yes, this must be an IGMPv2 router. */
ip_ptr -> nx_ip_igmp_router_version = NX_IGMP_HOST_VERSION_2;
/* Parse the max response time from the IGMP header. */
max_update_time = (USHORT)((header_ptr -> nx_igmp_header_word_0 & NX_IGMP_MAX_RESP_TIME_MASK) >> 16) & 0x0000FF;
/* Convert from tenths of a second to seconds. */
max_update_time /= 10;
}
else
{
/* No; IGMPv1 requires setting this field to zero. */
ip_ptr -> nx_ip_igmp_router_version = NX_IGMP_HOST_VERSION_1;
}
#endif
/* Then generate a random update time initially in timer ticks for the delay. */
update_time = tx_time_get() & 0xF;
/* Check we have a valid non zero update time that does not exceed the
maximum response time. */
if ((update_time > max_update_time) || (update_time == 0))
{
/* If not, wrap the update time back to one second. */
update_time = 1;
}
/* Loop through the multicast join list and assign an arbitrary timeout to
respond between 1 and maximum response time for each group. */
for (i = 0; i < NX_MAX_MULTICAST_GROUPS; i++)
{
/* Is there a group address in this slot? */
if (ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_join_list == NX_NULL)
{
/* No, skip doing further processing. */
continue;
}
/* Does the group address in the header match our join list? */
if ((ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_join_list != header_ptr -> nx_igmp_header_word_1) &&
/* or is this a general membership query? */
(header_ptr -> nx_igmp_header_word_1 != NX_NULL))
{
/* No; so no need to update the timer, skip to the next group in the host list. */
continue;
}
/* Is the current host group running timer less than the max delay? */
if (((ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_update_time < max_update_time) &&
(ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_update_time != NX_NULL)) ||
(ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_update_time == NX_WAIT_FOREVER))
{
/* Yes; Let the current timer timeout. Skip to the next group. */
continue;
}
/* Set the timeout for this multicast group. */
ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_update_time = update_time;
/* Then increment the update time for the next host group so the update/expiration times
are separated by one second. This avoids bursts of IGMP reports to the server. */
update_time++;
/* Check after each multicast group that we have not exceeded the maximum response time. */
if (update_time > max_update_time)
{
/* We have, so wrap the update time back to one. */
update_time = 1;
}
}
}
#ifndef NX_DISABLE_IGMPV2
/* Is this another IGMPv1 host's join request? */
else if (((header_ptr -> nx_igmp_header_word_0 & NX_IGMP_TYPE_MASK) == NX_IGMP_HOST_RESPONSE_TYPE) ||
/* ...Or an IGMPv2 host's join request? */
((header_ptr -> nx_igmp_header_word_0 & NX_IGMPV2_TYPE_MASK) == NX_IGMP_HOST_V2_JOIN_TYPE))
#else
/* Is this another IGMPv1 host's join request? */
else if ((header_ptr -> nx_igmp_header_word_0 & NX_IGMP_TYPE_MASK) == NX_IGMP_HOST_RESPONSE_TYPE)
#endif
{
/* Yes; Loop through the host multicast join list to find a matching group. */
for (i = 0; i < NX_MAX_MULTICAST_GROUPS; i++)
{
/* Compare the group address in the header with the host list. Is this a match? */
if ((ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_join_list == header_ptr -> nx_igmp_header_word_1) &&
(ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_update_time != NX_WAIT_FOREVER))
{
/* Yes; Clear the update time. This will cancel sending a join
request for the same multicast group. */
ip_ptr -> nx_ipv4_multicast_entry[i].nx_ipv4_multicast_update_time = 0;
break;
}
}
}
/* Release the IGMP packet. */
_nx_packet_release(packet_ptr);
}
#endif /* !NX_DISABLE_IPV4 */