igmp_host_receive.c

路由器协议平台igmp协议设计实现源码。

/*
 $Log:: /OEM Source Code/igmp/igmp_host_receive.c                                                  $
 * 
 * 1     4/23/98 9:53p Release Engineer
 * Initial release
 * IGMP v4.1.0
 */
/************************************************************************/
/*  Copyright (C) 1997-1998 RouterWare, Inc.                            */
/*  Unpublished - rights reserved under the Copyright Laws of the       */
/*  United States.  Use, duplication, or disclosure by the              */
/*  Government is subject to restrictions as set forth in               */
/*  subparagraph (c)(1)(ii) of the Rights in Technical Data and         */
/*  Computer Software clause at 252.227-7013.                           */
/*  RouterWare, Inc., 3961 MacArthur Blvd. Suite 212, Newport Beach, CA */
/************************************************************************/
#include "igmp.h"
/********************************************************************************************/
static void igmp_host_process_membership_query (IGMP_MESSAGE *sptr_igmp_message);
/********************************************************************************************/
void igmp_host_process_received_message (IGMP_MESSAGE *sptr_igmp_message)
{
	char ip_address[IP_ADDRESS_PRINT_BUFFER_SIZE];
	IGMP_GROUP_CLASS *sptr_group_node;
	UINT port;
	
	port = sptr_igmp_message->receiving_port;

	switch (sptr_igmp_message->type)
		{
		case IGMP_MEMBERSHIP_QUERY:
			igmp_host_process_membership_query (sptr_igmp_message);

			break;

		case IGMP_V1_MEMBERSHIP_REPORT:
		case IGMP_V2_MEMBERSHIP_REPORT:
			sptr_group_node =  igmp_get_matching_group_node_on_port (sptr_igmp_message->group_ip_address, port);

			if (sptr_group_node == NULL)
				{
				IGMP_PROTOCOL_ALARM_TRACE (IGMP_ALARM_TRACE, "IGMP Host: Unable to locate node for group %s on port %u for received report.\n",
						convert_ip_address_to_dot_format (&ip_address[0], sptr_igmp_message->group_ip_address), port);

				return ;
				}
				
			sptr_group_node->ip_address_of_last_reporter = sptr_igmp_message->source_ip_address;
			sptr_group_node->igmpCacheEntry.igmpCacheLastReporter = sptr_group_node->ip_address_of_last_reporter;

			if (sptr_group_node->host_group.state == IGMP_HOST_GROUP_DELAYING_MEMBER_STATE)
				{
				igmp_process_host_group_state_transition (port, sptr_igmp_message->group_ip_address, IGMP_HOST_GROUP_REPORT_RECEIVED_EVENT);
				}
			
			break;

		case IGMP_LEAVE_GROUP:
			/* IGNORE THE LEAVE GROUP MESSAGE */
			break;
	
		default:
			IGMP_PROTOCOL_ALARM_TRACE (IGMP_ALARM_TRACE, "IGMP Host: IGMP message received on port %u has INVALID message type.\n",
				port);

			break;
		}
}
/********************************************************************************************/
static void igmp_host_process_membership_query (IGMP_MESSAGE *sptr_igmp_message)
{
	char ip_address[IP_ADDRESS_PRINT_BUFFER_SIZE];
	IGMP_GROUP_CLASS *sptr_group_node;
	UINT port;
	ULONG group_ip_address;
	UINT max_response_time;

	port = sptr_igmp_message->receiving_port;

	group_ip_address = sptr_igmp_message->group_ip_address;

	max_response_time = sptr_igmp_message->max_response_time;

	igmp.port_table[port].ip_address_of_querier = sptr_igmp_message->source_ip_address;
	igmp.port_table[port].igmpInterfaceEntry.igmpInterfaceQuerier = igmp.port_table[port].ip_address_of_querier;

	/*
	NOTE that the check for v1 querier is done before taking appropriate actions for groups for an
	important reason. If it was a v1 querier then it would expect a v1 report. and the send routine
	would already know of the kind of report to send out.		
	*/
	if (sptr_igmp_message->max_response_time == 0) /* V1 Query */
		{
		IGMP_PROTOCOL_TRACE (IGMP_TRACE, "IGMP Host: Received Query was generated by V1 router with IP address %s\n",
			convert_ip_address_to_dot_format (&ip_address[0], igmp.port_table[port].ip_address_of_querier));

		/* start V1 router present timer */
		igmp.port_table[port].max_response_time_from_most_recent_query = IGMP_HOST_DEFAULT_V1_MAX_RESPONSE_TIME; /* seconds */
		igmp.port_table[port].host_port.v1_router_present = TRUE;
		igmp.port_table[port].host_port.v1_router_present_timer = 0;

		igmp.port_table[port].igmpInterfaceEntry.igmpInterfaceVersion1QuerierTimer = IGMP_HOST_V1_ROUTER_PRESENT_TIMEOUT;
		}
	else /* V2 Query */
		{
		igmp.port_table[port].max_response_time_from_most_recent_query = max_response_time / IGMP_HOST_RESPONSE_TIME_DIVIDER; /* seconds */
		}

	igmp.port_table[port].igmpInterfaceEntry.igmpInterfaceQueryMaxResponseTime = igmp.port_table[port].max_response_time_from_most_recent_query;

	if (group_ip_address == 0x00000000L) /* General Query */
		{
		for (sptr_group_node = (IGMP_GROUP_CLASS *) get_pointer_to_first_entry_in_list ((LINK *) &igmp.port_table[port].active_group_list);
			sptr_group_node != NULL;
			sptr_group_node = (IGMP_GROUP_CLASS *) get_pointer_to_next_entry_in_list ((LINK *) &sptr_group_node->links))
	 		{
			group_ip_address = sptr_group_node->multicast_group_ip_address;

			igmp_process_host_group_state_transition (port, group_ip_address, IGMP_HOST_GROUP_QUERY_RECEIVED_EVENT);
	 		}
		}
	else /* Group Specific Query */
		{
		sptr_group_node =  igmp_get_matching_group_node_on_port (group_ip_address, port);

		if (sptr_group_node == NULL)
			{
			IGMP_PROTOCOL_ALARM_TRACE (IGMP_ALARM_TRACE, "IGMP Host: Unable to locate node for group %s on port %u for received group specific query.\n",
				convert_ip_address_to_dot_format (&ip_address[0], group_ip_address), port);

			return ;
			}
			
		if ((sptr_group_node->host_group.state == IGMP_HOST_GROUP_DELAYING_MEMBER_STATE) || 
			(sptr_group_node->host_group.state == IGMP_HOST_GROUP_IDLE_MEMBER_STATE))
			{
			igmp_process_host_group_state_transition (port, group_ip_address, IGMP_HOST_GROUP_QUERY_RECEIVED_EVENT);
			}
		}
}