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incubator-nuttx/net/mld/mld_query.c

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/****************************************************************************
* net/mld/mld_query.c
*
* Copyright (C) 2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of CITEL Technologies Ltd nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY CITEL TECHNOLOGIES AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL CITEL TECHNOLOGIES OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/wdog.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/netstats.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/mld.h>
#include "devif/devif.h"
#include "inet/inet.h"
#include "mld/mld.h"
#include "utils/utils.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define IPv6BUF ((FAR struct ipv6_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)])
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: mld_mrc2mrd
*
* Description:
* Convert the MLD Maximum Response Code (MRC) to the Maximum Response
* Delay (MRD) in units of system clock ticks.
*
****************************************************************************/
static clock_t mld_mrc2mrd(uint16_t mrc)
{
uint32_t mrd; /* Units of milliseconds */
/* If bit 15 is not set (i.e., mrc < 32768), then no conversion is required. */
if (mrc < 32768)
{
mrd = mrc;
}
else
{
/* Conversion required */
mrd = MLD_MRD_VALUE(mrc);
}
/* Return the MRD in units of clock ticks */
return MSEC2TICK((clock_t)mrd);
}
/****************************************************************************
* Name: mld_cmpaddr
*
* Description:
* Perform a numerical comparison of the IPv6 Source Address and the IPv6
* address of the link. Return true if the source address is less than
* the link address.
*
****************************************************************************/
static bool mld_cmpaddr(FAR struct net_driver_s *dev,
const net_ipv6addr_t srcaddr)
{
int i;
for (i = 0; i < 8; i++)
{
if (srcaddr[i] < dev->d_ipv6addr[i])
{
return true;
}
}
return false;
}
/****************************************************************************
* Name: mld_check_querier
*
* Description:
* Perform a numerical comparison of the IPv6 Source Address and the IPv6
* address of the link. Return true if the source address is less than
* the link address.
*
****************************************************************************/
static void mld_check_querier(FAR struct net_driver_s *dev,
FAR struct ipv6_hdr_s *ipv6,
FAR struct mld_group_s *member,
uint16_t mrc)
{
clock_t ticks;
/* Check if this member is a Querier */
if (IS_MLD_QUERIER(member->flags))
{
/* This is a querier, check if the IPv6 source address is numerically
* less than the IPv6 address assigned to this link.
*/
if (mld_cmpaddr(dev, ipv6->srcipaddr))
{
/* This is a querier, then switch to non-querier and set a timeout.
* If additional queries are received within this timeout period,
* then we need to revert to Querier.
*/
ticks = mld_mrc2mrd(mrc);
if (mld_cmptimer(member, ticks))
{
mld_starttimer(member, ticks);
CLR_MLD_QUERIER(member->flags);
}
}
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mld_query
*
* Description:
* Called from icmpv6_input() when a Multicast Listener Query is received.
*
* A router may assume one of two roles: Querier or Non-Querier. There is
* normally only one Querier per link. All routers start up as a Querier
* on each of their attached links. If a router hears a Query message
* whose IPv6 Source Address is numerically less than its own selected
* address for that link, it MUST become a Non-Querier on that link. If a
* delay passes without receiving, from a particular attached link, any
* Queries from a router with an address less than its own, a router
* resumes the role of Querier on that link.
*
* A Querier for a link periodically sends a General Query on that link,
* to solicit reports of all multicast addresses of interest on that link.
* On startup, a router SHOULD send multiple General Queries spaced closely
* together Interval] on all attached links in order to quickly and
* reliably discover the presence of multicast listeners on those links.
*
****************************************************************************/
int mld_query(FAR struct net_driver_s *dev,
FAR const struct mld_mcast_listen_query_s *query)
{
FAR struct ipv6_hdr_s *ipv6 = IPv6BUF;
FAR struct mld_group_s *group;
uint16_t mrc;
bool unspec;
ninfo("Multicast Listener Query\n");
ninfo("destipaddr: %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
ipv6->destipaddr[0], ipv6->destipaddr[1], ipv6->destipaddr[2],
ipv6->destipaddr[3], ipv6->destipaddr[4], ipv6->destipaddr[5],
ipv6->destipaddr[6], ipv6->destipaddr[7]);
/* Find the group (or create a new one) using the incoming IP address */
group = mld_grpallocfind(dev, ipv6->destipaddr);
if (group == NULL)
{
nerr("ERROR: Failed to allocate/find group\n");
return -ENOENT;
}
/* Max Response Time. The Max Response Time field is meaningful only in
* Query messages, and specifies the maximum allowed time before sending
* a responding report in units of 1/10 second. In all other messages,
* it is set to zero by the sender and ignored by receivers.
*/
/* Check if the query was sent to all systems */
unspec = net_ipv6addr_cmp(query->grpaddr, g_ipv6_unspecaddr);
mrc = NTOHS(query->mrc);
if (net_ipv6addr_cmp(ipv6->destipaddr, g_ipv6_allnodes))
{
/* There are three variants of the Query message (RFC 3810):
*
* 1. A "General Query" is sent by the Querier to learn which
* multicast addresses have listeners on an attached link. In a
* General Query, both the Multicast Address field and the Number
* of Sources (N) field are zero.
* 2. A "Multicast Address Specific Query" is sent by the Querier to
* learn if a particular multicast address has any listeners on an
* attached link. In a Multicast Address Specific Query, the
* Multicast Address field contains the multicast address of
* interest, while the Number of Sources (N) field is set to zero.
* 3. A "Multicast Address and Source Specific Query" is sent by the
* Querier to learn if any of the sources from the specified list for
* the particular multicast address has any listeners on an attached
* link or not. In a Multicast Address and Source Specific Query the
* Multicast Address field contains the multicast address of
* interest, while the Source Address [i] field(s) contain(s) the
* source address(es) of interest.
*/
if (unspec && query->nsources == 0)
{
FAR struct mld_group_s *member;
/* This is the general query */
ninfo("General multicast query\n");
MLD_STATINCR(g_netstats.mld.gmq_query_received);
for (member = (FAR struct mld_group_s *)dev->d_mld_grplist.head;
member;
member = member->next)
{
/* Skip over the all systems group entry */
if (!net_ipv6addr_cmp(member->grpaddr, g_ipv6_allnodes))
{
/* REVISIT: Missing logic. No action is taken on the query. */
mld_check_querier(dev, ipv6, member, mrc);
}
}
}
else if (!unspec && query->nsources == 0)
{
ninfo("Multicast Address Specific Query\n");
MLD_STATINCR(g_netstats.mld.mas_query_received);
/* We first need to re-lookup the group since we used the incoming
* dest last time. Use the group address in the query.
*/
group = mld_grpallocfind(dev, query->grpaddr);
/* REVISIT: Missing logic. No action is taken on the query. */
mld_check_querier(dev, ipv6, group, mrc);
}
else
{
ninfo("Multicast Address and Source Specific Query\n");
MLD_STATINCR(g_netstats.mld.massq_query_received);
/* We first need to re-lookup the group since we used the incoming
* dest last time. Use the group address in the query.
*/
group = mld_grpallocfind(dev, query->grpaddr);
/* REVISIT: Missing logic. No action is taken on the query. */
mld_check_querier(dev, ipv6, group, mrc);
}
}
/* Not sent to all systems -- Unicast query */
else if (!unspec)
{
ninfo("Unicast query\n");
MLD_STATINCR(g_netstats.mld.ucast_query_received);
mld_check_querier(dev, ipv6, group, mrc);
}
return OK;
}
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