contiki/core/net/ipv6/multicast/smrf.c
George Oikonomou 5efb3f0769 Tidy-up multicast documentation
* Create a doxygen group and add files to it, so that documents appear as modules rather than simply under files
* Document plenty of functions, macros, constants, data types which were previously undocumented
* Re-structure some doxygen comments to improve structure and readability
2015-02-15 23:29:59 +01:00

215 lines
7.1 KiB
C

/*
* Copyright (c) 2010, Loughborough University - Computer Science
* All rights reserved.
*
* 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 the Institute 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 THE INSTITUTE 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 THE INSTITUTE 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.
*
* This file is part of the Contiki operating system.
*/
/**
* \addtogroup smrf-multicast
* @{
*/
/**
* \file
* This file implements 'Stateless Multicast RPL Forwarding' (SMRF)
*
* \author
* George Oikonomou - <oikonomou@users.sourceforge.net>
*/
#include "contiki.h"
#include "contiki-net.h"
#include "net/ipv6/multicast/uip-mcast6.h"
#include "net/ipv6/multicast/uip-mcast6-route.h"
#include "net/ipv6/multicast/uip-mcast6-stats.h"
#include "net/ipv6/multicast/smrf.h"
#include "net/rpl/rpl.h"
#include "net/netstack.h"
#include <string.h>
#define DEBUG DEBUG_NONE
#include "net/ip/uip-debug.h"
/*---------------------------------------------------------------------------*/
/* Macros */
/*---------------------------------------------------------------------------*/
/* CCI */
#define SMRF_FWD_DELAY() NETSTACK_RDC.channel_check_interval()
/* Number of slots in the next 500ms */
#define SMRF_INTERVAL_COUNT ((CLOCK_SECOND >> 2) / fwd_delay)
/*---------------------------------------------------------------------------*/
/* Internal Data */
/*---------------------------------------------------------------------------*/
static struct ctimer mcast_periodic;
static uint8_t mcast_len;
static uip_buf_t mcast_buf;
static uint8_t fwd_delay;
static uint8_t fwd_spread;
/*---------------------------------------------------------------------------*/
/* uIPv6 Pointers */
/*---------------------------------------------------------------------------*/
#define UIP_IP_BUF ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
/*---------------------------------------------------------------------------*/
static void
mcast_fwd(void *p)
{
memcpy(uip_buf, &mcast_buf, mcast_len);
uip_len = mcast_len;
UIP_IP_BUF->ttl--;
tcpip_output(NULL);
uip_len = 0;
}
/*---------------------------------------------------------------------------*/
static uint8_t
in()
{
rpl_dag_t *d; /* Our DODAG */
uip_ipaddr_t *parent_ipaddr; /* Our pref. parent's IPv6 address */
const uip_lladdr_t *parent_lladdr; /* Our pref. parent's LL address */
/*
* Fetch a pointer to the LL address of our preferred parent
*
* ToDo: This rpl_get_any_dag() call is a dirty replacement of the previous
* rpl_get_dag(RPL_DEFAULT_INSTANCE);
* so that things can compile with the new RPL code. This needs updated to
* read instance ID from the RPL HBHO and use the correct parent accordingly
*/
d = rpl_get_any_dag();
if(!d) {
UIP_MCAST6_STATS_ADD(mcast_dropped);
return UIP_MCAST6_DROP;
}
/* Retrieve our preferred parent's LL address */
parent_ipaddr = rpl_get_parent_ipaddr(d->preferred_parent);
parent_lladdr = uip_ds6_nbr_lladdr_from_ipaddr(parent_ipaddr);
if(parent_lladdr == NULL) {
UIP_MCAST6_STATS_ADD(mcast_dropped);
return UIP_MCAST6_DROP;
}
/*
* We accept a datagram if it arrived from our preferred parent, discard
* otherwise.
*/
if(memcmp(parent_lladdr, packetbuf_addr(PACKETBUF_ADDR_SENDER),
UIP_LLADDR_LEN)) {
PRINTF("SMRF: Routable in but SMRF ignored it\n");
UIP_MCAST6_STATS_ADD(mcast_dropped);
return UIP_MCAST6_DROP;
}
if(UIP_IP_BUF->ttl <= 1) {
UIP_MCAST6_STATS_ADD(mcast_dropped);
return UIP_MCAST6_DROP;
}
UIP_MCAST6_STATS_ADD(mcast_in_all);
UIP_MCAST6_STATS_ADD(mcast_in_unique);
/* If we have an entry in the mcast routing table, something with
* a higher RPL rank (somewhere down the tree) is a group member */
if(uip_mcast6_route_lookup(&UIP_IP_BUF->destipaddr)) {
/* If we enter here, we will definitely forward */
UIP_MCAST6_STATS_ADD(mcast_fwd);
/*
* Add a delay (D) of at least SMRF_FWD_DELAY() to compensate for how
* contikimac handles broadcasts. We can't start our TX before the sender
* has finished its own.
*/
fwd_delay = SMRF_FWD_DELAY();
/* Finalise D: D = min(SMRF_FWD_DELAY(), SMRF_MIN_FWD_DELAY) */
#if SMRF_MIN_FWD_DELAY
if(fwd_delay < SMRF_MIN_FWD_DELAY) {
fwd_delay = SMRF_MIN_FWD_DELAY;
}
#endif
if(fwd_delay == 0) {
/* No delay required, send it, do it now, why wait? */
UIP_IP_BUF->ttl--;
tcpip_output(NULL);
UIP_IP_BUF->ttl++; /* Restore before potential upstack delivery */
} else {
/* Randomise final delay in [D , D*Spread], step D */
fwd_spread = SMRF_INTERVAL_COUNT;
if(fwd_spread > SMRF_MAX_SPREAD) {
fwd_spread = SMRF_MAX_SPREAD;
}
if(fwd_spread) {
fwd_delay = fwd_delay * (1 + ((random_rand() >> 11) % fwd_spread));
}
memcpy(&mcast_buf, uip_buf, uip_len);
mcast_len = uip_len;
ctimer_set(&mcast_periodic, fwd_delay, mcast_fwd, NULL);
}
PRINTF("SMRF: %u bytes: fwd in %u [%u]\n",
uip_len, fwd_delay, fwd_spread);
}
/* Done with this packet unless we are a member of the mcast group */
if(!uip_ds6_is_my_maddr(&UIP_IP_BUF->destipaddr)) {
PRINTF("SMRF: Not a group member. No further processing\n");
return UIP_MCAST6_DROP;
} else {
PRINTF("SMRF: Ours. Deliver to upper layers\n");
UIP_MCAST6_STATS_ADD(mcast_in_ours);
return UIP_MCAST6_ACCEPT;
}
}
/*---------------------------------------------------------------------------*/
static void
init()
{
UIP_MCAST6_STATS_INIT(NULL);
uip_mcast6_route_init();
}
/*---------------------------------------------------------------------------*/
static void
out()
{
return;
}
/*---------------------------------------------------------------------------*/
/**
* \brief The SMRF engine driver
*/
const struct uip_mcast6_driver smrf_driver = {
"SMRF",
init,
out,
in,
};
/*---------------------------------------------------------------------------*/
/** @} */