/**************************************************************************** * net/mld/mld_query.c * * Copyright (C) 2018 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #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; }