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 --- Makefile.kbuild | 1 + distributed-arp-table.c | 272 +++++++++++++++++++++++++++++++++++++++++++++++ distributed-arp-table.h | 49 +++++++++ hard-interface.c | 3 + main.h | 6 ++ originator.c | 2 + types.h | 14 +++ unicast.c | 8 +- unicast.h | 4 + 9 files changed, 355 insertions(+), 4 deletions(-) create mode 100644 distributed-arp-table.c create mode 100644 distributed-arp-table.h
diff --git a/Makefile.kbuild b/Makefile.kbuild index 8676d2b..7604159 100644 --- a/Makefile.kbuild +++ b/Makefile.kbuild @@ -23,6 +23,7 @@ batman-adv-y += bat_iv_ogm.o batman-adv-y += bitarray.o batman-adv-$(CONFIG_BATMAN_ADV_BLA) += bridge_loop_avoidance.o batman-adv-y += debugfs.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..64beacf --- /dev/null +++ b/distributed-arp-table.c @@ -0,0 +1,272 @@ +/* Copyright (C) 2011-2012 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" + +/** + * batadv_hash_dat_global - compute the hash value for the global DAT cache + * + * @data: data to hash + * @size: size of the hash table + * + * Returns the selected index in the hash table for the given data + */ +static uint32_t batadv_hash_dat_global(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; +} + +/** + * batadv_is_orig_node_eligible - check whether a node can be a DHT candidate + * + * @res: the array with the already selected candidates + * @select: number of already selected candidates + * @tmp_max: address of the currently evaluated node + * @max: current round max address + * @last_max: address of the last selected candidate + * @candidate: orig_node under evaluation + * @max_orig_node: last selected candidate + * + * Returns true if the node has been elected as next candidate or false othrwise + */ +static bool batadv_is_orig_node_eligible(struct batadv_dht_candidate *res, + int select, batadv_dat_addr_t tmp_max, + batadv_dat_addr_t max, + batadv_dat_addr_t last_max, + struct batadv_orig_node *candidate, + struct batadv_orig_node *max_orig_node) +{ + bool ret = false; + int j; + + /* Check if we have already selected this neighbour... */ + for (j = 0; j < select; j++) + if (res[j].orig_node == candidate) + break; + /* ..and possibly skip it */ + if (j < select) + goto out; + /* sanity check: has it already been selected? This should not happen */ + if (tmp_max > last_max) + goto out; + /* check if during this iteration we have already found an originator + * with a closer dht address + */ + if (tmp_max < max) + goto out; + /* this is an hash collision with the temporary selected node. Choose + * the one with the lowest address + */ + if ((tmp_max == max) && + (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0)) + goto out; + + ret = true; +out: + return ret; +} + +/** + * batadv_choose_next_candidate - select the next DHT candidate + * + * @bat_priv: the bat priv with all the soft interface information + * @cands: candidates array + * @select: number of candidates already present in the array + * @ip_key: key we want to look up in the DHT + * @last_max: pointer where the address of the selected candidate will be saved + */ +static void batadv_choose_next_candidate(struct batadv_priv *bat_priv, + struct batadv_dht_candidate *cands, + int select, batadv_dat_addr_t ip_key, + batadv_dat_addr_t *last_max) +{ + batadv_dat_addr_t max = 0, tmp_max = 0; + struct batadv_orig_node *orig_node, *max_orig_node = NULL; + struct batadv_hashtable *hash = bat_priv->orig_hash; + struct hlist_node *node; + struct hlist_head *head; + int i; + + /* if no node is eligible as candidate, we will leave the candidate as + * NOT_FOUND + */ + cands[select].type = DHT_CANDIDATE_NOT_FOUND; + + /* iterate over the originator list and find the node with closest + * dht_address which has not been selected yet + */ + 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) { + /* the dht space is a ring and addresses are unsigned */ + tmp_max = BATADV_DAT_ADDR_MAX - orig_node->dht_addr + + ip_key; + + if (!batadv_is_orig_node_eligible(cands, select, + tmp_max, max, + *last_max, orig_node, + max_orig_node)) + continue; + + if (!atomic_inc_not_zero(&orig_node->refcount)) + continue; + + max = tmp_max; + if (max_orig_node) + batadv_orig_node_free_ref(max_orig_node); + max_orig_node = orig_node; + } + rcu_read_unlock(); + } + if (max_orig_node) { + cands[select].type = DHT_CANDIDATE_ORIG; + cands[select].orig_node = max_orig_node; + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "dht_select_candidates() %d: selected %pM addr=%u dist=%u\n", + select, max_orig_node->orig, max_orig_node->dht_addr, + max); + } + *last_max = max; +} + +/** + * batadv_dht_select_candidates - 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 (from the LEFT, with wrap + * around if needed) then the hash value of the key. ip_dst is the key. + * + * @bat_priv: the bat priv with all the soft interface information + * @ip_dst: ipv4 to look up in the DHT + * + * Returns the candidate array of size DHT_CANDIDATE_NUM + */ +static struct batadv_dht_candidate * +batadv_dht_select_candidates(struct batadv_priv *bat_priv, __be32 ip_dst) +{ + int select; + batadv_dat_addr_t last_max = BATADV_DAT_ADDR_MAX, ip_key; + struct batadv_dht_candidate *res; + + if (!bat_priv->orig_hash) + return NULL; + + res = kmalloc(DHT_CANDIDATES_NUM * sizeof(*res), GFP_ATOMIC); + if (!res) + return NULL; + + ip_key = (batadv_dat_addr_t)batadv_hash_dat_global(&ip_dst, + BATADV_DAT_ADDR_MAX); + + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "dht_select_candidates(): IP=%pI4 hash(IP)=%u\n", &ip_dst, + ip_key); + + for (select = 0; select < DHT_CANDIDATES_NUM; select++) + batadv_choose_next_candidate(bat_priv, res, select, ip_key, + &last_max); + + return res; +} + +/** + * batadv_dht_send_data - send a payload to the candidates selected for the + * given key. The skb is copied by means of pskb_copy() and is sent as unicast + * packet to each of the selected candidate. + * + * @bat_priv: the bat priv with all the soft interface information + * @skb: payload to send + * @ip: the DHT key + * @packet_subtype: unicast4addr packet subtype to use + * + * Returns true if the packet is sent to at least one candidate, false otherwise + */ +static bool batadv_dht_send_data(struct batadv_priv *bat_priv, + struct sk_buff *skb, __be32 ip, + int packet_subtype) +{ + int i; + bool ret = false; + int send_status; + struct batadv_neigh_node *neigh_node = NULL; + struct sk_buff *tmp_skb; + struct batadv_dht_candidate *cand; + + cand = batadv_dht_select_candidates(bat_priv, ip); + if (!cand) + goto out; + + batadv_dbg(BATADV_DBG_DAT, bat_priv, "DHT_SEND for %pI4\n", &ip); + + for (i = 0; i < DHT_CANDIDATES_NUM; i++) { + if (cand[i].type == DHT_CANDIDATE_NOT_FOUND) + continue; + + neigh_node = batadv_orig_node_get_router(cand[i].orig_node); + if (!neigh_node) + goto free_orig; + + tmp_skb = pskb_copy(skb, GFP_ATOMIC); + if (!batadv_prepare_unicast_4addr_packet(bat_priv, tmp_skb, + cand[i].orig_node, + packet_subtype)) { + kfree_skb(tmp_skb); + goto free_neigh; + } + + send_status = batadv_send_skb_packet(tmp_skb, + neigh_node->if_incoming, + neigh_node->addr); + if (send_status == NET_XMIT_SUCCESS) + /* packet sent to a candidate: we can return true */ + ret = true; +free_neigh: + batadv_neigh_node_free_ref(neigh_node); +free_orig: + batadv_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..8d26c90 --- /dev/null +++ b/distributed-arp-table.h @@ -0,0 +1,49 @@ +/* Copyright (C) 2011-2012 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_ + +#include "types.h" +#include "originator.h" + +#define BATADV_DAT_ADDR_MAX ((batadv_dat_addr_t)~(batadv_dat_addr_t)0) + +static inline void +batadv_dat_init_orig_node_dht_addr(struct batadv_orig_node *orig_node) +{ + uint32_t addr; + + addr = batadv_choose_orig(orig_node->orig, BATADV_DAT_ADDR_MAX); + orig_node->dht_addr = (batadv_dat_addr_t)addr; +} + +static inline void +batadv_dat_init_own_dht_addr(struct batadv_priv *bat_priv, + struct batadv_hard_iface *primary_if) +{ + uint32_t addr; + + addr = batadv_choose_orig(primary_if->net_dev->dev_addr, + BATADV_DAT_ADDR_MAX); + + bat_priv->dht_addr = (batadv_dat_addr_t)addr; +} + +#endif /* _NET_BATMAN_ADV_ARP_H_ */ diff --git a/hard-interface.c b/hard-interface.c index 2c5a247..0f55cca 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -18,6 +18,7 @@ */
#include "main.h" +#include "distributed-arp-table.h" #include "hard-interface.h" #include "soft-interface.h" #include "send.h" @@ -108,6 +109,8 @@ static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv, if (!primary_if) goto out;
+ batadv_dat_init_own_dht_addr(bat_priv, primary_if); + vis_packet = (struct batadv_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 7e64dbd..076dbc5 100644 --- a/main.h +++ b/main.h @@ -73,6 +73,9 @@
#define BATADV_LOG_BUF_LEN 8192 /* has to be a power of 2 */
+/* numbers of originator to contact for any PUT/GET DHT operation */ +#define DHT_CANDIDATES_NUM 3 + #define BATADV_VIS_INTERVAL 5000 /* 5 seconds */
/* how much worse secondary interfaces may be to be considered as bonding @@ -117,6 +120,9 @@ enum batadv_uev_type {
#define BATADV_GW_THRESHOLD 50
+#define DHT_CANDIDATE_NOT_FOUND 0 +#define DHT_CANDIDATE_ORIG 1 + /* Debug Messages */ #ifdef pr_fmt #undef pr_fmt diff --git a/originator.c b/originator.c index ac9bdf8..06f8bd6 100644 --- a/originator.c +++ b/originator.c @@ -18,6 +18,7 @@ */
#include "main.h" +#include "distributed-arp-table.h" #include "originator.h" #include "hash.h" #include "translation-table.h" @@ -223,6 +224,7 @@ struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv, orig_node->tt_poss_change = false; orig_node->bat_priv = bat_priv; memcpy(orig_node->orig, addr, ETH_ALEN); + batadv_dat_init_orig_node_dht_addr(orig_node); orig_node->router = NULL; orig_node->tt_crc = 0; atomic_set(&orig_node->last_ttvn, 0); diff --git a/types.h b/types.h index 591bd28..f9de55a 100644 --- a/types.h +++ b/types.h @@ -28,6 +28,13 @@ (ETH_HLEN + max(sizeof(struct batadv_unicast_packet), \ sizeof(struct batadv_bcast_packet)))
+/* batadv_dat_addr_t is the type used for all DHT addresses. If it is changed, + * BATADV_DAT_ADDR_MAX is changed as well. + * + * *Please be careful: batadv_dat_addr_t must be UNSIGNED* + */ +#define batadv_dat_addr_t uint16_t + struct batadv_hard_iface { struct list_head list; int16_t if_num; @@ -62,6 +69,7 @@ struct batadv_orig_node { uint8_t orig[ETH_ALEN]; uint8_t primary_addr[ETH_ALEN]; struct batadv_neigh_node __rcu *router; /* rcu protected pointer */ + batadv_dat_addr_t dht_addr; unsigned long *bcast_own; uint8_t *bcast_own_sum; unsigned long last_seen; @@ -241,6 +249,7 @@ struct batadv_priv { struct batadv_hard_iface __rcu *primary_if; /* rcu protected pointer */ struct batadv_vis_info *my_vis_info; struct batadv_algo_ops *bat_algo_ops; + batadv_dat_addr_t dht_addr; };
struct batadv_socket_client { @@ -413,4 +422,9 @@ struct batadv_algo_ops { void (*bat_ogm_emit)(struct batadv_forw_packet *forw_packet); };
+struct batadv_dht_candidate { + int type; + struct batadv_orig_node *orig_node; +}; + #endif /* _NET_BATMAN_ADV_TYPES_H_ */ diff --git a/unicast.c b/unicast.c index 3621d99..d14fb18 100644 --- a/unicast.c +++ b/unicast.c @@ -344,10 +344,10 @@ static bool batadv_prepare_unicast_packet(struct sk_buff *skb, * * Returns false if the payload could not be encapsulated or true otherwise */ -static bool batadv_prepare_unicast_4addr_packet(struct batadv_priv *bat_priv, - struct sk_buff *skb, - struct batadv_orig_node *orig, - int packet_subtype) +bool batadv_prepare_unicast_4addr_packet(struct batadv_priv *bat_priv, + struct sk_buff *skb, + struct batadv_orig_node *orig, + int packet_subtype) { struct batadv_hard_iface *primary_if; struct batadv_unicast_4addr_packet *unicast_4addr_packet; diff --git a/unicast.h b/unicast.h index 23d526e..9ce8c04 100644 --- a/unicast.h +++ b/unicast.h @@ -32,6 +32,10 @@ void batadv_frag_list_free(struct list_head *head); int batadv_frag_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv, struct batadv_hard_iface *hard_iface, const uint8_t dstaddr[]); +bool batadv_prepare_unicast_4addr_packet(struct batadv_priv *bat_priv, + struct sk_buff *skb, + struct batadv_orig_node *orig_node, + int packet_subtype); int batadv_unicast_generic_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv, int packet_type, int packet_subtype);