routing_table.c

/*****************************************************************************
 *
 * Copyright (C) 2001 Uppsala University and Ericsson AB.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Authors: Erik Nordström, <erik.nordstrom@it.uu.se>
 *
 *****************************************************************************/

#include <time.h>

#ifdef NS_PORT
#include "ns-2/aodv-uu.h"
#else
#include "aodv_hello.h"
#include "aodv_neighbor.h"
#include "aodv_rerr.h"
#include "aodv_socket.h"
#include "aodv_timeout.h"
#include "debug.h"
#include "defs.h"
#include "nl.h"
#include "params.h"
#include "routing_table.h"
#include "seek_list.h"
#include "timer_queue.h"
#endif /* NS_PORT */

static unsigned int hashing(struct in_addr *addr, hash_value *hash);

extern int llfeedback;

void NS_CLASS rt_table_init()
{
    int i;

    rt_tbl.num_entries = 0;
    rt_tbl.num_active = 0;

    /* We do a for loop here... NS does not like us to use memset() */
    for (i = 0; i < RT_TABLESIZE; i++) {
        INIT_LIST_HEAD(&rt_tbl.tbl[i]);
    }
}

void NS_CLASS rt_table_destroy()
{
    int i;
    list_t *tmp = NULL, *pos = NULL;

    for (i = 0; i < RT_TABLESIZE; i++) {
        list_foreach_safe(pos, tmp, &rt_tbl.tbl[i])
        {
            rt_table_t *rt = (rt_table_t *)pos;

            rt_table_delete(rt);
        }
    }
}

/* Calculate a hash value and table index given a key... */
unsigned int hashing(struct in_addr *addr, hash_value *hash)
{
    /*   *hash = (*addr & 0x7fffffff); */
    *hash = (hash_value)addr->s_addr;

    return (*hash & RT_TABLEMASK);
}

rt_table_t *NS_CLASS rt_table_insert(struct in_addr dest_addr,
                                     struct in_addr next, u_int8_t hops,
                                     u_int32_t seqno, u_int32_t life,
                                     u_int8_t state, u_int16_t flags,
                                     unsigned int ifindex)
{
    hash_value hash;
    unsigned int index;
    list_t *pos;
    rt_table_t *rt;

    /* Calculate hash key */
    index = hashing(&dest_addr, &hash);

    /* Check if we already have an entry for dest_addr */
    list_foreach(pos, &rt_tbl.tbl[index])
    {
        rt = (rt_table_t *)pos;
        if (memcmp(&rt->dest_addr, &dest_addr, sizeof(struct in_addr)) == 0) {
            DEBUG(LOG_INFO, 0, "%s already exist in routing table!",
                  ip_to_str(dest_addr));

            return NULL;
        }
    }

    if ((rt = (rt_table_t *)malloc(sizeof(rt_table_t))) == NULL) {
        fprintf(stderr, "Malloc failed!\n");
        exit(-1);
    }

    memset(rt, 0, sizeof(rt_table_t));

    rt->dest_addr = dest_addr;
    rt->next_hop = next;
    rt->dest_seqno = seqno;
    rt->flags = flags;
    rt->hcnt = hops;
    rt->ifindex = ifindex;
    rt->hash = hash;
    rt->state = state;

    timer_init(&rt->rt_timer, &NS_CLASS route_expire_timeout, rt);

    timer_init(&rt->ack_timer, &NS_CLASS rrep_ack_timeout, rt);

    timer_init(&rt->hello_timer, &NS_CLASS hello_timeout, rt);

    rt->last_hello_time.tv_sec = 0;
    rt->last_hello_time.tv_usec = 0;
    rt->hello_cnt = 0;

    rt->nprec = 0;
    INIT_LIST_HEAD(&rt->precursors);

    /* Insert first in bucket... */

    rt_tbl.num_entries++;

    DEBUG(LOG_INFO, 0, "Inserting %s (bucket %d) next hop %s",
          ip_to_str(dest_addr), index, ip_to_str(next));

    list_add(&rt_tbl.tbl[index], &rt->l);

    if (state == INVALID) {

        if (flags & RT_REPAIR) {
            rt->rt_timer.handler = &NS_CLASS local_repair_timeout;
            life = ACTIVE_ROUTE_TIMEOUT;
        } else {
            rt->rt_timer.handler = &NS_CLASS route_delete_timeout;
            life = DELETE_PERIOD;
        }

    } else {
        rt_tbl.num_active++;
#ifndef NS_PORT
        nl_send_add_route_msg(dest_addr, next, hops, life, flags, ifindex);
#endif
    }

#ifdef CONFIG_GATEWAY_DISABLE
    if (rt->flags & RT_GATEWAY)
        rt_table_update_inet_rt(rt, life);
#endif

    //#ifdef NS_PORT
    DEBUG(LOG_INFO, 0, "New timer for %s, life=%d", ip_to_str(rt->dest_addr),
          life);

    if (life != 0)
        timer_set_timeout(&rt->rt_timer, life);
    //#endif
    /* In case there are buffered packets for this destination, we
     * send them on the new route. */
    if (rt->state == VALID && seek_list_remove(seek_list_find(dest_addr))) {
#ifdef NS_PORT
        if (rt->flags & RT_INET_DEST)
            packet_queue_set_verdict(dest_addr, PQ_ENC_SEND);
        else
            packet_queue_set_verdict(dest_addr, PQ_SEND);
#endif
    }
    return rt;
}

rt_table_t *NS_CLASS rt_table_update(rt_table_t *rt, struct in_addr next,
                                     u_int8_t hops, u_int32_t seqno,
                                     u_int32_t lifetime, u_int8_t state,
                                     u_int16_t flags)
{
    if (rt->state == INVALID && state == VALID) {

        /* If this previously was an expired route, but will now be
           active again we must add it to the kernel routing
           table... */
        rt_tbl.num_active++;

        if (rt->flags & RT_REPAIR)
            flags &= ~RT_REPAIR;

#ifndef NS_PORT
        nl_send_add_route_msg(rt->dest_addr, next, hops, lifetime, flags,
                              rt->ifindex);
#endif

    } else if (rt->next_hop.s_addr != 0 && rt->next_hop.s_addr != next.s_addr) {

        DEBUG(LOG_INFO, 0, "rt->next_hop=%s, new_next_hop=%s",
              ip_to_str(rt->next_hop), ip_to_str(next));

#ifndef NS_PORT
        nl_send_add_route_msg(rt->dest_addr, next, hops, lifetime, flags,
                              rt->ifindex);
#endif
    }

    if (hops > 1 && rt->hcnt == 1) {
        rt->last_hello_time.tv_sec = 0;
        rt->last_hello_time.tv_usec = 0;
        rt->hello_cnt = 0;
        timer_remove(&rt->hello_timer);
        /* Must also do a "link break" when updating a 1 hop
        neighbor in case another routing entry use this as
        next hop... */
        neighbor_link_break(rt);
    }

    rt->flags = flags;
    rt->dest_seqno = seqno;
    rt->next_hop = next;
    rt->hcnt = hops;

#ifdef CONFIG_GATEWAY
    if (rt->flags & RT_GATEWAY)
        rt_table_update_inet_rt(rt, lifetime);
#endif

    //#ifdef NS_PORT
    rt->rt_timer.handler = &NS_CLASS route_expire_timeout;

    if (!(rt->flags & RT_INET_DEST))
        rt_table_update_timeout(rt, lifetime);
    //#endif

    /* Finally, mark as VALID */
    rt->state = state;

    /* In case there are buffered packets for this destination, we send
     * them on the new route. */
    if (rt->state == VALID && seek_list_remove(seek_list_find(rt->dest_addr))) {
#ifdef NS_PORT
        if (rt->flags & RT_INET_DEST)
            packet_queue_set_verdict(rt->dest_addr, PQ_ENC_SEND);
        else
            packet_queue_set_verdict(rt->dest_addr, PQ_SEND);
#endif
    }
    return rt;
}

rt_table_t *NS_CLASS rt_table_update_timeout(rt_table_t *rt,
                                                       u_int32_t lifetime)
{
    struct timeval new_timeout;

    if (!rt)
        return NULL;

    if (rt->state == VALID) {
        /* Check if the current valid timeout is larger than the new
           one - in that case keep the old one. */
        gettimeofday(&new_timeout, NULL);
        timeval_add_msec(&new_timeout, lifetime);

        if (timeval_diff(&rt->rt_timer.timeout, &new_timeout) < 0)
            timer_set_timeout(&rt->rt_timer, lifetime);
    } else
        timer_set_timeout(&rt->rt_timer, lifetime);

    return rt;
}

/* Update route timeouts in response to an incoming or outgoing data packet. */
void NS_CLASS rt_table_update_route_timeouts(rt_table_t *fwd_rt,
                                             rt_table_t *rev_rt)
{
    rt_table_t *next_hop_rt = NULL;

    /* When forwarding a packet, we update the lifetime of the
       destination's routing table entry, as well as the entry for the
       next hop neighbor (if not the same). AODV draft 10, section
       6.2. */

    if (fwd_rt && fwd_rt->state == VALID) {

        if (llfeedback || fwd_rt->flags & RT_INET_DEST || fwd_rt->hcnt != 1 ||
            fwd_rt->hello_timer.used)
            rt_table_update_timeout(fwd_rt, ACTIVE_ROUTE_TIMEOUT);

        next_hop_rt = rt_table_find(fwd_rt->next_hop);

        if (next_hop_rt && next_hop_rt->state == VALID &&
            next_hop_rt->dest_addr.s_addr != fwd_rt->dest_addr.s_addr &&
            (llfeedback || fwd_rt->hello_timer.used))
            rt_table_update_timeout(next_hop_rt, ACTIVE_ROUTE_TIMEOUT);
    }
    /* Also update the reverse route and reverse next hop along the
       path back, since routes between originators and the destination
       are expected to be symmetric. */
    if (rev_rt && rev_rt->state == VALID) {

        if (llfeedback || rev_rt->hcnt != 1 || rev_rt->hello_timer.used)
            rt_table_update_timeout(rev_rt, ACTIVE_ROUTE_TIMEOUT);

        next_hop_rt = rt_table_find(rev_rt->next_hop);

        if (next_hop_rt && next_hop_rt->state == VALID && rev_rt &&
            next_hop_rt->dest_addr.s_addr != rev_rt->dest_addr.s_addr &&
            (llfeedback || rev_rt->hello_timer.used))
            rt_table_update_timeout(next_hop_rt, ACTIVE_ROUTE_TIMEOUT);

        /* Update HELLO timer of next hop neighbor if active */
        /* 	if (!llfeedback && next_hop_rt->hello_timer.used) { */
        /* 	    struct timeval now; */

        /* 	    gettimeofday(&now, NULL); */
        /* 	    hello_update_timeout(next_hop_rt, &now,  */
        /* 				 ALLOWED_HELLO_LOSS * HELLO_INTERVAL);
         */
        /* 	} */
    }
}

rt_table_t *NS_CLASS rt_table_find(struct in_addr dest_addr)
{
    hash_value hash;
    unsigned int index;
    list_t *pos;

    if (rt_tbl.num_entries == 0)
        return NULL;

    /* Calculate index */
    index = hashing(&dest_addr, &hash);

    /* Handle collisions: */
    list_foreach(pos, &rt_tbl.tbl[index])
    {
        rt_table_t *rt = (rt_table_t *)pos;

        if (rt->hash != hash)
            continue;

        if (memcmp(&dest_addr, &rt->dest_addr, sizeof(struct in_addr)) == 0)
            return rt;
    }
    return NULL;
}

rt_table_t *NS_CLASS rt_table_find_gateway()
{
    rt_table_t *gw = NULL;
    int i;

    for (i = 0; i < RT_TABLESIZE; i++) {
        list_t *pos;
        list_foreach(pos, &rt_tbl.tbl[i])
        {
            rt_table_t *rt = (rt_table_t *)pos;

            if (rt->flags & RT_GATEWAY && rt->state == VALID) {
                if (!gw || rt->hcnt < gw->hcnt)
                    gw = rt;
            }
        }
    }
    return gw;
}

#ifdef CONFIG_GATEWAY
int NS_CLASS rt_table_update_inet_rt(rt_table_t *gw, u_int32_t life)
{
    int n = 0;
    int i;

    if (!gw)
        return -1;

    for (i = 0; i < RT_TABLESIZE; i++) {
        list_t *pos;
        list_foreach(pos, &rt_tbl.tbl[i])
        {
            rt_table_t *rt = (rt_table_t *)pos;

            if (rt->flags & RT_INET_DEST && rt->state == VALID) {
                rt_table_update(rt, gw->dest_addr, gw->hcnt, 0, life, VALID,
                                rt->flags);
                n++;
            }
        }
    }
    return n;
}
#endif /* CONFIG_GATEWAY_DISABLED */

/* Route expiry and Deletion. */
int NS_CLASS rt_table_invalidate(rt_table_t *rt)
{
    struct timeval now;

    gettimeofday(&now, NULL);

    if (rt == NULL)
        return -1;

    /* If the route is already invalidated, do nothing... */
    if (rt->state == INVALID) {
        DEBUG(LOG_DEBUG, 0, "Route %s already invalidated!!!",
              ip_to_str(rt->dest_addr));
        return -1;
    }

    if (rt->hello_timer.used) {
        DEBUG(LOG_DEBUG, 0, "last HELLO: %ld",
              timeval_diff(&now, &rt->last_hello_time));
    }

    /* Remove any pending, but now obsolete timers. */
    timer_remove(&rt->rt_timer);
    timer_remove(&rt->hello_timer);
    timer_remove(&rt->ack_timer);

    /* Mark the route as invalid */
    rt->state = INVALID;
    rt_tbl.num_active--;

    rt->hello_cnt = 0;

    /* When the lifetime of a route entry expires, increase the sequence
       number for that entry. */
    seqno_incr(rt->dest_seqno);

    rt->last_hello_time.tv_sec = 0;
    rt->last_hello_time.tv_usec = 0;

#ifndef NS_PORT
    nl_send_del_route_msg(rt->dest_addr, rt->next_hop, rt->hcnt);
#endif

#ifdef CONFIG_GATEWAY
    /* If this was a gateway, check if any Internet destinations were using
     * it. In that case update them to use a backup gateway or invalide them
     * too. */
    if (rt->flags & RT_GATEWAY) {
        int i;

        rt_table_t *gw = rt_table_find_gateway();

        for (i = 0; i < RT_TABLESIZE; i++) {
            list_t *pos;
            list_foreach(pos, &rt_tbl.tbl[i])
            {
                rt_table_t *rt2 = (rt_table_t *)pos;

                if (rt2->state == VALID && (rt2->flags & RT_INET_DEST) &&
                    (rt2->next_hop.s_addr == rt->dest_addr.s_addr)) {
                    if (0) {
                        DEBUG(LOG_DEBUG, 0,
                              "Invalidated GW %s but found new GW %s for %s",
                              ip_to_str(rt->dest_addr),
                              ip_to_str(gw->dest_addr),
                              ip_to_str(rt2->dest_addr));
                        rt_table_update(
                            rt2, gw->dest_addr, gw->hcnt, 0,
                            timeval_diff(&rt->rt_timer.timeout, &now), VALID,
                            rt2->flags);
                    } else {
                        rt_table_invalidate(rt2);
                        precursor_list_destroy(rt2);
                    }
                }
            }
        }
    }
#endif

    if (rt->flags & RT_REPAIR) {
        /* Set a timeout for the repair */

        rt->rt_timer.handler = &NS_CLASS local_repair_timeout;
        timer_set_timeout(&rt->rt_timer, ACTIVE_ROUTE_TIMEOUT);

        DEBUG(LOG_DEBUG, 0, "%s kept for repairs during %u msecs",
              ip_to_str(rt->dest_addr), ACTIVE_ROUTE_TIMEOUT);
    } else {

        /* Schedule a deletion timer */
        rt->rt_timer.handler = &NS_CLASS route_delete_timeout;
        timer_set_timeout(&rt->rt_timer, DELETE_PERIOD);

        DEBUG(LOG_DEBUG, 0, "%s removed in %u msecs", ip_to_str(rt->dest_addr),
              DELETE_PERIOD);
    }

    return 0;
}

void NS_CLASS rt_table_delete(rt_table_t *rt)
{
    if (!rt) {
        DEBUG(LOG_ERR, 0, "No route entry to delete");
        return;
    }

    list_detach(&rt->l);

    precursor_list_destroy(rt);

    if (rt->state == VALID) {

#ifndef NS_PORT
        nl_send_del_route_msg(rt->dest_addr, rt->next_hop, rt->hcnt);
#endif
        rt_tbl.num_active--;
    }
    /* Make sure timers are removed... */
    timer_remove(&rt->rt_timer);
    timer_remove(&rt->hello_timer);
    timer_remove(&rt->ack_timer);

    rt_tbl.num_entries--;

    free(rt);
    return;
}

/****************************************************************/

/* Add an neighbor to the active neighbor list. */

void NS_CLASS precursor_add(rt_table_t *rt, struct in_addr addr)
{
    precursor_t *pr;
    list_t *pos;

    /* Sanity check */
    if (!rt)
        return;

    /* Check if the node is already in the precursors list. */
    list_foreach(pos, &rt->precursors)
    {
        pr = (precursor_t *)pos;

        if (pr->neighbor.s_addr == addr.s_addr)
            return;
    }

    if ((pr = (precursor_t *)malloc(sizeof(precursor_t))) == NULL) {
        perror("Could not allocate memory for precursor node!!\n");
        exit(-1);
    }

    DEBUG(LOG_INFO, 0, "Adding precursor %s to rte %s", ip_to_str(addr),
          ip_to_str(rt->dest_addr));

    pr->neighbor.s_addr = addr.s_addr;

    /* Insert in precursors list */

    list_add(&rt->precursors, &pr->l);
    rt->nprec++;

    return;
}

/****************************************************************/

/* Remove a neighbor from the active neighbor list. */

void NS_CLASS precursor_remove(rt_table_t *rt, struct in_addr addr)
{
    list_t *pos;

    /* Sanity check */
    if (!rt)
        return;

    list_foreach(pos, &rt->precursors)
    {
        precursor_t *pr = (precursor_t *)pos;
        if (pr->neighbor.s_addr == addr.s_addr) {
            DEBUG(LOG_INFO, 0, "Removing precursor %s from rte %s",
                  ip_to_str(addr), ip_to_str(rt->dest_addr));

            list_detach(pos);
            rt->nprec--;
            free(pr);
            return;
        }
    }
}

/****************************************************************/

/* Delete all entries from the active neighbor list. */

void precursor_list_destroy(rt_table_t *rt)
{
    list_t *pos, *tmp;

    /* Sanity check */
    if (!rt)
        return;

    list_foreach_safe(pos, tmp, &rt->precursors)
    {
        precursor_t *pr = (precursor_t *)pos;
        list_detach(pos);
        rt->nprec--;
        free(pr);
    }
}