Add all the relevant functions in order to manage a Distributed Hash Table over the B.A.T.M.A.N.-adv network. It will later be used to store several ARP entries and implement DAT (Distributed ARP Table)
Signed-off-by: Antonio Quartulli ordex@autistici.org Reviewed-by: Simon Wunderlich siwu@hrz.tu-chemnitz.de --- Makefile.kbuild | 1 + distributed-arp-table.c | 181 +++++++++++++++++++++++++++++++++++++++++++++++ distributed-arp-table.h | 46 ++++++++++++ hard-interface.c | 2 + main.h | 7 ++ originator.c | 1 + soft-interface.c | 2 + types.h | 7 ++ 8 files changed, 247 insertions(+), 0 deletions(-) create mode 100644 distributed-arp-table.c create mode 100644 distributed-arp-table.h
diff --git a/Makefile.kbuild b/Makefile.kbuild index bd7e93c..e8861cb 100644 --- a/Makefile.kbuild +++ b/Makefile.kbuild @@ -36,6 +36,7 @@ batman-adv-y += bat_debugfs.o batman-adv-y += bat_iv_ogm.o batman-adv-y += bat_sysfs.o batman-adv-y += bitarray.o +batman-adv-y += distributed-arp-table.o batman-adv-y += gateway_client.o batman-adv-y += gateway_common.o batman-adv-y += hard-interface.o diff --git a/distributed-arp-table.c b/distributed-arp-table.c new file mode 100644 index 0000000..5bc3004 --- /dev/null +++ b/distributed-arp-table.c @@ -0,0 +1,181 @@ +/* + * Copyright (C) 2011 B.A.T.M.A.N. contributors: + * + * Antonio Quartulli + * + * 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 <linux/if_ether.h> +#include <linux/if_arp.h> + +#include "main.h" +#include "distributed-arp-table.h" +#include "hard-interface.h" +#include "originator.h" +#include "send.h" +#include "types.h" +#include "unicast.h" + +/* Given a key, selects the candidates which the DHT message has to be sent to. + * An originator O is selected if and only if its DHT_ID value is one of three + * closest values (but not greater) then the hash value of the key. + * ip_dst is the key. + * + * return an array of size DHT_CANDIDATES_NUM */ +static struct dht_candidate *dht_select_candidates(struct bat_priv *bat_priv, + uint32_t ip_dst) +{ + struct hashtable_t *hash = bat_priv->orig_hash; + struct hlist_node *node; + struct hlist_head *head; + struct orig_node *orig_node, *max_orig_node = NULL; + int select, i, j; + uint16_t last_max = USHRT_MAX, max, tmp_max, ip_key; + struct dht_candidate *res; + bool chosen_me = false; + + if (!hash) + return NULL; + + res = kmalloc(DHT_CANDIDATES_NUM * sizeof(*res), GFP_ATOMIC); + if (!res) + return NULL; + + ip_key = hash_ipv4(&ip_dst, USHRT_MAX); + + bat_dbg(DBG_ARP, bat_priv, "DHT_SEL_CAND key: %pI4 %u\n", &ip_dst, + ip_key); + + for (select = 0; select < DHT_CANDIDATES_NUM; select++) { + max = 0; + max_orig_node = NULL; + if (!chosen_me) { + /* if true, wrap around the key space */ + if (bat_priv->dht_hash > ip_key) + max = USHRT_MAX - bat_priv->dht_hash + + ip_key; + else + max = ip_key - bat_priv->dht_hash; + max = bat_priv->dht_hash; + res[select].type = DHT_CANDIDATE_ME; + } else + res[select].type = DHT_CANDIDATE_NULL; + /* for all origins... */ + for (i = 0; i < hash->size; i++) { + head = &hash->table[i]; + + rcu_read_lock(); + hlist_for_each_entry_rcu(orig_node, node, head, + hash_entry) { + if (orig_node->dht_hash > ip_key) + tmp_max = USHRT_MAX - + orig_node->dht_hash + ip_key; + else + tmp_max = ip_key - orig_node->dht_hash; + + /* this is closest! */ + if (tmp_max <= max) + continue; + + /* this has already been selected */ + if (tmp_max > last_max) + continue; + + /* In case of hash collision we can select two + * nodes with the same hash, but we have ensure + * they are different */ + if (tmp_max == last_max) { + for (j = 0; j < select; j++) + if (res[j].orig_node == + orig_node) + break; + if (j < select) + continue; + } + + if (!atomic_inc_not_zero(&orig_node->refcount)) + continue; + + max = tmp_max; + if (max_orig_node) + orig_node_free_ref(max_orig_node); + max_orig_node = orig_node; + } + rcu_read_unlock(); + } + last_max = max; + if (max_orig_node) { + res[select].type = DHT_CANDIDATE_ORIG; + res[select].orig_node = max_orig_node; + bat_dbg(DBG_ARP, bat_priv, "DHT_SEL_CAND %d: %pM %u\n", + select, max_orig_node->orig, max); + } + if (res[select].type == DHT_CANDIDATE_ME) { + chosen_me = true; + bat_dbg(DBG_ARP, bat_priv, "DHT_SEL_CAND %d: ME %u\n", + select, bat_priv->dht_hash); + } + + max_orig_node = NULL; + } + + return res; +} + +/* + * Sends the skb payload passed as argument to the candidates selected for + * 'ip'. The skb is copied by means of pskb_copy() and is sent as unicast packet + * to each of the selected candidate. */ +static bool dht_send_data(struct bat_priv *bat_priv, struct sk_buff *skb, + uint32_t ip) +{ + int i; + bool ret = false; + struct neigh_node *neigh_node = NULL; + struct sk_buff *tmp_skb; + struct dht_candidate *cand = dht_select_candidates(bat_priv, ip); + + if (!cand) + goto out; + + bat_dbg(DBG_ARP, bat_priv, "DHT_SEND for %pI4\n", &ip); + + for (i = 0; i < DHT_CANDIDATES_NUM; i++) { + if (cand[i].type == DHT_CANDIDATE_ME || + cand[i].type == DHT_CANDIDATE_NULL) + continue; + + neigh_node = orig_node_get_router(cand[i].orig_node); + if (!neigh_node) + goto free_orig; + + tmp_skb = pskb_copy(skb, GFP_ATOMIC); + tmp_skb = prepare_unicast_packet(tmp_skb, cand[i].orig_node); + if (tmp_skb) + send_skb_packet(tmp_skb, neigh_node->if_incoming, + neigh_node->addr); + /* set ret to true only if we send at least one request */ + ret = true; + neigh_node_free_ref(neigh_node); +free_orig: + orig_node_free_ref(cand[i].orig_node); + } + +out: + kfree(cand); + return ret; +} diff --git a/distributed-arp-table.h b/distributed-arp-table.h new file mode 100644 index 0000000..ee1a8b3 --- /dev/null +++ b/distributed-arp-table.h @@ -0,0 +1,46 @@ +/* + * Copyright (C) 2011 B.A.T.M.A.N. contributors: + * + * Antonio Quartulli + * + * 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 + * + */ + +#ifndef _NET_BATMAN_ADV_ARP_H_ +#define _NET_BATMAN_ADV_ARP_H_ + +/* hash function to choose an entry in a hash table of given size */ +/* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */ +static inline uint32_t hash_ipv4(const void *data, uint32_t size) +{ + const unsigned char *key = data; + uint32_t hash = 0; + size_t i; + + for (i = 0; i < 4; i++) { + hash += key[i]; + hash += (hash << 10); + hash ^= (hash >> 6); + } + + hash += (hash << 3); + hash ^= (hash >> 11); + hash += (hash << 15); + + return hash % size; +} + +#endif /* _NET_BATMAN_ADV_ARP_H_ */ diff --git a/hard-interface.c b/hard-interface.c index 7704df4..3508934 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -117,6 +117,8 @@ static void primary_if_update_addr(struct bat_priv *bat_priv) if (!primary_if) goto out;
+ bat_priv->dht_hash = choose_orig(bat_priv, USHRT_MAX); + vis_packet = (struct vis_packet *) bat_priv->my_vis_info->skb_packet->data; memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN); diff --git a/main.h b/main.h index e706193..7b4229c 100644 --- a/main.h +++ b/main.h @@ -64,6 +64,9 @@
#define NULL_IFINDEX 0 /* dummy ifindex used to avoid iface checks */
+/* numbers of originator to contact for any STORE/GET DHT operation */ +#define DHT_CANDIDATES_NUM 3 + #define NUM_WORDS (TQ_LOCAL_WINDOW_SIZE / WORD_BIT_SIZE)
#define LOG_BUF_LEN 8192 /* has to be a power of 2 */ @@ -106,6 +109,10 @@ enum uev_type {
#define GW_THRESHOLD 50
+#define DHT_CANDIDATE_NULL 0 +#define DHT_CANDIDATE_ME 1 +#define DHT_CANDIDATE_ORIG 2 + /* * Debug Messages */ diff --git a/originator.c b/originator.c index 0bc2045..9673b44 100644 --- a/originator.c +++ b/originator.c @@ -222,6 +222,7 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, const uint8_t *addr) orig_node->tt_poss_change = false; orig_node->bat_priv = bat_priv; memcpy(orig_node->orig, addr, ETH_ALEN); + orig_node->dht_hash = choose_orig(addr, USHRT_MAX); orig_node->router = NULL; orig_node->tt_crc = 0; atomic_set(&orig_node->last_ttvn, 0); diff --git a/soft-interface.c b/soft-interface.c index 987c75a..cd6c9ea 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -855,6 +855,8 @@ struct net_device *softif_create(const char *name) bat_priv->primary_if = NULL; bat_priv->num_ifaces = 0;
+ bat_priv->dht_hash = 0; + ret = sysfs_add_meshif(soft_iface); if (ret < 0) goto unreg_soft_iface; diff --git a/types.h b/types.h index e9eb043..5f0030e 100644 --- a/types.h +++ b/types.h @@ -67,6 +67,7 @@ struct hard_iface { struct orig_node { uint8_t orig[ETH_ALEN]; uint8_t primary_addr[ETH_ALEN]; + uint16_t dht_hash; struct neigh_node __rcu *router; /* rcu protected pointer */ unsigned long *bcast_own; uint8_t *bcast_own_sum; @@ -204,6 +205,7 @@ struct bat_priv { struct gw_node __rcu *curr_gw; /* rcu protected pointer */ atomic_t gw_reselect; struct hard_iface __rcu *primary_if; /* rcu protected pointer */ + uint16_t dht_hash; struct vis_info *my_vis_info; };
@@ -343,4 +345,9 @@ struct softif_neigh { struct rcu_head rcu; };
+struct dht_candidate { + int type; + struct orig_node *orig_node; +}; + #endif /* _NET_BATMAN_ADV_TYPES_H_ */