Merge branch 'next-spi' of git://git.secretlab.ca/git/linux-2.6

[mirror_ubuntu-kernels.git] / drivers / staging / batman-adv / vis.c

/*
 * Copyright (C) 2008-2009 B.A.T.M.A.N. contributors:
 *
 * Simon Wunderlich
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 *
 */

#include "main.h"
#include "send.h"
#include "translation-table.h"
#include "vis.h"
#include "log.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "hash.h"
#include "compat.h"

struct hashtable_t *vis_hash;
DEFINE_SPINLOCK(vis_hash_lock);
static struct vis_info *my_vis_info;
static struct list_head send_list;      /* always locked with vis_hash_lock */

static void start_vis_timer(void);

/* free the info */
static void free_info(void *data)
{
        struct vis_info *info = data;
        struct recvlist_node *entry, *tmp;

        list_del_init(&info->send_list);
        list_for_each_entry_safe(entry, tmp, &info->recv_list, list) {
                list_del(&entry->list);
                kfree(entry);
        }
        kfree(info);
}

/* set the mode of the visualization to client or server */
void vis_set_mode(int mode)
{
        spin_lock(&vis_hash_lock);

        if (my_vis_info != NULL)
                my_vis_info->packet.vis_type = mode;

        spin_unlock(&vis_hash_lock);
}

/* is_vis_server(), locked outside */
static int is_vis_server_locked(void)
{
        if (my_vis_info != NULL)
                if (my_vis_info->packet.vis_type == VIS_TYPE_SERVER_SYNC)
                        return 1;

        return 0;
}

/* get the current set mode */
int is_vis_server(void)
{
        int ret = 0;

        spin_lock(&vis_hash_lock);
        ret = is_vis_server_locked();
        spin_unlock(&vis_hash_lock);

        return ret;
}

/* Compare two vis packets, used by the hashing algorithm */
static int vis_info_cmp(void *data1, void *data2)
{
        struct vis_info *d1, *d2;
        d1 = data1;
        d2 = data2;
        return compare_orig(d1->packet.vis_orig, d2->packet.vis_orig);
}

/* hash function to choose an entry in a hash table of given size */
/* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */
static int vis_info_choose(void *data, int size)
{
        struct vis_info *vis_info = data;
        unsigned char *key;
        uint32_t hash = 0;
        size_t i;

        key = vis_info->packet.vis_orig;
        for (i = 0; i < ETH_ALEN; i++) {
                hash += key[i];
                hash += (hash << 10);
                hash ^= (hash >> 6);
        }

        hash += (hash << 3);
        hash ^= (hash >> 11);
        hash += (hash << 15);

        return hash % size;
}

/* tries to add one entry to the receive list. */
static void recv_list_add(struct list_head *recv_list, char *mac)
{
        struct recvlist_node *entry;
        entry = kmalloc(sizeof(struct recvlist_node), GFP_ATOMIC);
        if (!entry)
                return;

        memcpy(entry->mac, mac, ETH_ALEN);
        list_add_tail(&entry->list, recv_list);
}

/* returns 1 if this mac is in the recv_list */
static int recv_list_is_in(struct list_head *recv_list, char *mac)
{
        struct recvlist_node *entry;

        list_for_each_entry(entry, recv_list, list) {
                if (memcmp(entry->mac, mac, ETH_ALEN) == 0)
                        return 1;
        }

        return 0;
}

/* try to add the packet to the vis_hash. return NULL if invalid (e.g. too old,
 * broken.. ).  vis hash must be locked outside.  is_new is set when the packet
 * is newer than old entries in the hash. */
static struct vis_info *add_packet(struct vis_packet *vis_packet,
                                   int vis_info_len, int *is_new)
{
        struct vis_info *info, *old_info;
        struct vis_info search_elem;

        *is_new = 0;
        /* sanity check */
        if (vis_hash == NULL)
                return NULL;

        /* see if the packet is already in vis_hash */
        memcpy(search_elem.packet.vis_orig, vis_packet->vis_orig, ETH_ALEN);
        old_info = hash_find(vis_hash, &search_elem);

        if (old_info != NULL) {
                if (vis_packet->seqno - old_info->packet.seqno <= 0) {
                        if (old_info->packet.seqno == vis_packet->seqno) {
                                recv_list_add(&old_info->recv_list,
                                              vis_packet->sender_orig);
                                return old_info;
                        } else {
                                /* newer packet is already in hash. */
                                return NULL;
                        }
                }
                /* remove old entry */
                hash_remove(vis_hash, old_info);
                free_info(old_info);
        }

        info = kmalloc(sizeof(struct vis_info) + vis_info_len, GFP_ATOMIC);
        if (info == NULL)
                return NULL;

        INIT_LIST_HEAD(&info->send_list);
        INIT_LIST_HEAD(&info->recv_list);
        info->first_seen = jiffies;
        memcpy(&info->packet, vis_packet,
               sizeof(struct vis_packet) + vis_info_len);

        /* initialize and add new packet. */
        *is_new = 1;

        /* repair if entries is longer than packet. */
        if (info->packet.entries * sizeof(struct vis_info_entry) > vis_info_len)
                info->packet.entries = vis_info_len / sizeof(struct vis_info_entry);

        recv_list_add(&info->recv_list, info->packet.sender_orig);

        /* try to add it */
        if (hash_add(vis_hash, info) < 0) {
                /* did not work (for some reason) */
                free_info(info);
                info = NULL;
        }

        return info;
}

/* handle the server sync packet, forward if needed. */
void receive_server_sync_packet(struct vis_packet *vis_packet, int vis_info_len)
{
        struct vis_info *info;
        int is_new;

        spin_lock(&vis_hash_lock);
        info = add_packet(vis_packet, vis_info_len, &is_new);
        if (info == NULL)
                goto end;

        /* only if we are server ourselves and packet is newer than the one in
         * hash.*/
        if (is_vis_server_locked() && is_new) {
                memcpy(info->packet.target_orig, broadcastAddr, ETH_ALEN);
                if (list_empty(&info->send_list))
                        list_add_tail(&info->send_list, &send_list);
        }
end:
        spin_unlock(&vis_hash_lock);
}

/* handle an incoming client update packet and schedule forward if needed. */
void receive_client_update_packet(struct vis_packet *vis_packet,
                                  int vis_info_len)
{
        struct vis_info *info;
        int is_new;

        /* clients shall not broadcast. */
        if (is_bcast(vis_packet->target_orig))
                return;

        spin_lock(&vis_hash_lock);
        info = add_packet(vis_packet, vis_info_len, &is_new);
        if (info == NULL)
                goto end;
        /* note that outdated packets will be dropped at this point. */


        /* send only if we're the target server or ... */
        if (is_vis_server_locked() &&
            is_my_mac(info->packet.target_orig) &&
            is_new) {
                info->packet.vis_type = VIS_TYPE_SERVER_SYNC;   /* upgrade! */
                memcpy(info->packet.target_orig, broadcastAddr, ETH_ALEN);
                if (list_empty(&info->send_list))
                        list_add_tail(&info->send_list, &send_list);

                /* ... we're not the recipient (and thus need to forward). */
        } else if (!is_my_mac(info->packet.target_orig)) {
                if (list_empty(&info->send_list))
                        list_add_tail(&info->send_list, &send_list);
        }
end:
        spin_unlock(&vis_hash_lock);
}

/* Walk the originators and find the VIS server with the best tq. Set the packet
 * address to its address and return the best_tq.
 *
 * Must be called with the originator hash locked */
static int find_best_vis_server(struct vis_info *info)
{
        struct hash_it_t *hashit = NULL;
        struct orig_node *orig_node;
        int best_tq = -1;

        while (NULL != (hashit = hash_iterate(orig_hash, hashit))) {
                orig_node = hashit->bucket->data;
                if ((orig_node != NULL) &&
                    (orig_node->router != NULL) &&
                    (orig_node->flags & VIS_SERVER) &&
                    (orig_node->router->tq_avg > best_tq)) {
                        best_tq = orig_node->router->tq_avg;
                        memcpy(info->packet.target_orig, orig_node->orig,
                               ETH_ALEN);
                }
        }
        return best_tq;
}

/* Return true if the vis packet is full. */
static bool vis_packet_full(struct vis_info *info)
{
        if (info->packet.entries + 1 >
            (1000 - sizeof(struct vis_info)) / sizeof(struct vis_info_entry))
                return true;
        return false;
}

/* generates a packet of own vis data,
 * returns 0 on success, -1 if no packet could be generated */
static int generate_vis_packet(void)
{
        struct hash_it_t *hashit = NULL;
        struct orig_node *orig_node;
        struct vis_info *info = (struct vis_info *)my_vis_info;
        struct vis_info_entry *entry, *entry_array;
        struct hna_local_entry *hna_local_entry;
        int best_tq = -1;
        unsigned long flags;

        info->first_seen = jiffies;

        spin_lock(&orig_hash_lock);
        memcpy(info->packet.target_orig, broadcastAddr, ETH_ALEN);
        info->packet.ttl = TTL;
        info->packet.seqno++;
        info->packet.entries = 0;

        if (!is_vis_server_locked()) {
                best_tq = find_best_vis_server(info);
                if (best_tq < 0) {
                        spin_unlock(&orig_hash_lock);
                        return -1;
                }
        }
        hashit = NULL;

        entry_array = (struct vis_info_entry *)
                ((char *)info + sizeof(struct vis_info));

        while (NULL != (hashit = hash_iterate(orig_hash, hashit))) {
                orig_node = hashit->bucket->data;
                if (orig_node->router != NULL
                        && compare_orig(orig_node->router->addr, orig_node->orig)
                        && orig_node->batman_if
                        && (orig_node->batman_if->if_active == IF_ACTIVE)
                    && orig_node->router->tq_avg > 0) {

                        /* fill one entry into buffer. */
                        entry = &entry_array[info->packet.entries];
                        memcpy(entry->src, orig_node->batman_if->net_dev->dev_addr, ETH_ALEN);
                        memcpy(entry->dest, orig_node->orig, ETH_ALEN);
                        entry->quality = orig_node->router->tq_avg;
                        info->packet.entries++;

                        if (vis_packet_full(info)) {
                                spin_unlock(&orig_hash_lock);
                                return 0;
                        }
                }
        }

        spin_unlock(&orig_hash_lock);

        hashit = NULL;
        spin_lock_irqsave(&hna_local_hash_lock, flags);
        while (NULL != (hashit = hash_iterate(hna_local_hash, hashit))) {
                hna_local_entry = hashit->bucket->data;
                entry = &entry_array[info->packet.entries];
                memset(entry->src, 0, ETH_ALEN);
                memcpy(entry->dest, hna_local_entry->addr, ETH_ALEN);
                entry->quality = 0; /* 0 means HNA */
                info->packet.entries++;

                if (vis_packet_full(info)) {
                        spin_unlock_irqrestore(&hna_local_hash_lock, flags);
                        return 0;
                }
        }
        spin_unlock_irqrestore(&hna_local_hash_lock, flags);
        return 0;
}

static void purge_vis_packets(void)
{
        struct hash_it_t *hashit = NULL;
        struct vis_info *info;

        while (NULL != (hashit = hash_iterate(vis_hash, hashit))) {
                info = hashit->bucket->data;
                if (info == my_vis_info)        /* never purge own data. */
                        continue;
                if (time_after(jiffies,
                               info->first_seen + (VIS_TIMEOUT/1000)*HZ)) {
                        hash_remove_bucket(vis_hash, hashit);
                        free_info(info);
                }
        }
}

static void broadcast_vis_packet(struct vis_info *info, int packet_length)
{
        struct hash_it_t *hashit = NULL;
        struct orig_node *orig_node;

        spin_lock(&orig_hash_lock);

        /* send to all routers in range. */
        while (NULL != (hashit = hash_iterate(orig_hash, hashit))) {
                orig_node = hashit->bucket->data;

                /* if it's a vis server and reachable, send it. */
                if (orig_node &&
                    (orig_node->flags & VIS_SERVER) &&
                    orig_node->batman_if &&
                    orig_node->router) {

                        /* don't send it if we already received the packet from
                         * this node. */
                        if (recv_list_is_in(&info->recv_list, orig_node->orig))
                                continue;

                        memcpy(info->packet.target_orig,
                               orig_node->orig, ETH_ALEN);

                        send_raw_packet((unsigned char *) &info->packet,
                                        packet_length,
                                        orig_node->batman_if,
                                        orig_node->router->addr);
                }
        }
        memcpy(info->packet.target_orig, broadcastAddr, ETH_ALEN);
        spin_unlock(&orig_hash_lock);
}

static void unicast_vis_packet(struct vis_info *info, int packet_length)
{
        struct orig_node *orig_node;

        spin_lock(&orig_hash_lock);
        orig_node = ((struct orig_node *)
                     hash_find(orig_hash, info->packet.target_orig));

        if ((orig_node != NULL) &&
            (orig_node->batman_if != NULL) &&
            (orig_node->router != NULL)) {
                send_raw_packet((unsigned char *) &info->packet, packet_length,
                                orig_node->batman_if,
                                orig_node->router->addr);
        }
        spin_unlock(&orig_hash_lock);
}

/* only send one vis packet. called from send_vis_packets() */
static void send_vis_packet(struct vis_info *info)
{
        int packet_length;

        if (info->packet.ttl < 2) {
                debug_log(LOG_TYPE_NOTICE,
                          "Error - can't send vis packet: ttl exceeded\n");
                return;
        }

        memcpy(info->packet.sender_orig, mainIfAddr, ETH_ALEN);
        info->packet.ttl--;

        packet_length = sizeof(struct vis_packet) +
                info->packet.entries * sizeof(struct vis_info_entry);

        if (is_bcast(info->packet.target_orig))
                broadcast_vis_packet(info, packet_length);
        else
                unicast_vis_packet(info, packet_length);
        info->packet.ttl++; /* restore TTL */
}

/* called from timer; send (and maybe generate) vis packet. */
static void send_vis_packets(struct work_struct *work)
{
        struct vis_info *info, *temp;

        spin_lock(&vis_hash_lock);
        purge_vis_packets();

        if (generate_vis_packet() == 0)
                /* schedule if generation was successful */
                list_add_tail(&my_vis_info->send_list, &send_list);

        list_for_each_entry_safe(info, temp, &send_list, send_list) {
                list_del_init(&info->send_list);
                send_vis_packet(info);
        }
        spin_unlock(&vis_hash_lock);
        start_vis_timer();
}
static DECLARE_DELAYED_WORK(vis_timer_wq, send_vis_packets);

/* init the vis server. this may only be called when if_list is already
 * initialized (e.g. bat0 is initialized, interfaces have been added) */
int vis_init(void)
{
        if (vis_hash)
                return 1;

        spin_lock(&vis_hash_lock);

        vis_hash = hash_new(256, vis_info_cmp, vis_info_choose);
        if (!vis_hash) {
                debug_log(LOG_TYPE_CRIT, "Can't initialize vis_hash\n");
                goto err;
        }

        my_vis_info = kmalloc(1000, GFP_ATOMIC);
        if (!my_vis_info) {
                debug_log(LOG_TYPE_CRIT, "Can't initialize vis packet\n");
                goto err;
        }

        /* prefill the vis info */
        my_vis_info->first_seen = jiffies - atomic_read(&vis_interval);
        INIT_LIST_HEAD(&my_vis_info->recv_list);
        INIT_LIST_HEAD(&my_vis_info->send_list);
        my_vis_info->packet.version = COMPAT_VERSION;
        my_vis_info->packet.packet_type = BAT_VIS;
        my_vis_info->packet.vis_type = VIS_TYPE_CLIENT_UPDATE;
        my_vis_info->packet.ttl = TTL;
        my_vis_info->packet.seqno = 0;
        my_vis_info->packet.entries = 0;

        INIT_LIST_HEAD(&send_list);

        memcpy(my_vis_info->packet.vis_orig, mainIfAddr, ETH_ALEN);
        memcpy(my_vis_info->packet.sender_orig, mainIfAddr, ETH_ALEN);

        if (hash_add(vis_hash, my_vis_info) < 0) {
                debug_log(LOG_TYPE_CRIT,
                          "Can't add own vis packet into hash\n");
                free_info(my_vis_info); /* not in hash, need to remove it
                                         * manually. */
                goto err;
        }

        spin_unlock(&vis_hash_lock);
        start_vis_timer();
        return 1;

err:
        spin_unlock(&vis_hash_lock);
        vis_quit();
        return 0;
}

/* shutdown vis-server */
void vis_quit(void)
{
        if (!vis_hash)
                return;

        cancel_delayed_work_sync(&vis_timer_wq);

        spin_lock(&vis_hash_lock);
        /* properly remove, kill timers ... */
        hash_delete(vis_hash, free_info);
        vis_hash = NULL;
        my_vis_info = NULL;
        spin_unlock(&vis_hash_lock);
}

/* schedule packets for (re)transmission */
static void start_vis_timer(void)
{
        queue_delayed_work(bat_event_workqueue, &vis_timer_wq,
                           (atomic_read(&vis_interval)/1000) * HZ);
}