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 | 270 ++++++++++++++++++++++++++++++++++++++++++++++++ distributed-arp-table.h | 58 +++++++++++ hard-interface.c | 3 + main.h | 6 ++ originator.c | 2 + types.h | 30 ++++++ unicast.c | 8 +- unicast.h | 4 + 9 files changed, 378 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..ce39e8a --- /dev/null +++ b/distributed-arp-table.c @@ -0,0 +1,270 @@ +/* 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 - compute the hash value for an IP address + * @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(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_dat_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 this node has already been selected... */ + 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 an originator with a closer dht + * address has already been found + */ + 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 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_dat_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, leave the candidate type as + * NOT_FOUND + */ + cands[select].type = BATADV_DAT_CANDIDATE_NOT_FOUND; + + /* iterate over the originator list and find the node with closest + * dat_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->dat_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 = BATADV_DAT_CANDIDATE_ORIG; + cands[select].orig_node = max_orig_node; + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "dat_select_candidates() %d: selected %pM addr=%u dist=%u\n", + select, max_orig_node->orig, max_orig_node->dat_addr, + max); + } + *last_max = max; +} + +/** + * batadv_dat_select_candidates - selects the nodes which the DHT message has to + * be sent to + * @bat_priv: the bat priv with all the soft interface information + * @ip_dst: ipv4 to look up in the DHT + * + * 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. + * + * Returns the candidate array of size BATADV_DAT_CANDIDATE_NUM + */ +static struct batadv_dat_candidate * +batadv_dat_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_dat_candidate *res; + + if (!bat_priv->orig_hash) + return NULL; + + res = kmalloc(BATADV_DAT_CANDIDATES_NUM * sizeof(*res), GFP_ATOMIC); + if (!res) + return NULL; + + ip_key = (batadv_dat_addr_t)batadv_hash_dat(&ip_dst, + BATADV_DAT_ADDR_MAX); + + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "dat_select_candidates(): IP=%pI4 hash(IP)=%u\n", &ip_dst, + ip_key); + + for (select = 0; select < BATADV_DAT_CANDIDATES_NUM; select++) + batadv_choose_next_candidate(bat_priv, res, select, ip_key, + &last_max); + + return res; +} + +/** + * batadv_dat_send_data - send a payload to the selected candidates + * @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 + * + * In this function the skb is copied by means of pskb_copy() and is sent as + * unicast packet to each of the selected candidates + * + * Returns true if the packet is sent to at least one candidate, false otherwise + */ +static bool batadv_dat_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_dat_candidate *cand; + + cand = batadv_dat_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 < BATADV_DAT_CANDIDATES_NUM; i++) { + if (cand[i].type == BATADV_DAT_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_unicast_4addr_prepare_skb(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: 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..5df02bd --- /dev/null +++ b/distributed-arp-table.h @@ -0,0 +1,58 @@ +/* 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) + +/** + * batadv_dat_init_orig_node_addr - assign a DAT address to the orig_node + * @orig_node: the node to assign the DAT address to + */ +static inline void +batadv_dat_init_orig_node_addr(struct batadv_orig_node *orig_node) +{ + uint32_t addr; + + addr = batadv_choose_orig(orig_node->orig, BATADV_DAT_ADDR_MAX); + orig_node->dat_addr = (batadv_dat_addr_t)addr; +} + +/** + * batadv_dat_init_own_addr - assign a DAT address to the node itself + * @bat_priv: the bat priv with all the soft interface information + * @primary_if: a pointer to the primary interface + */ +static inline void +batadv_dat_init_own_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->dat.addr = (batadv_dat_addr_t)addr; +} + +#endif /* _NET_BATMAN_ADV_ARP_H_ */ diff --git a/hard-interface.c b/hard-interface.c index 81f1771..365ed74 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" @@ -148,6 +149,8 @@ static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv, if (!primary_if) goto out;
+ batadv_dat_init_own_addr(bat_priv, primary_if); + skb = bat_priv->vis.my_info->skb_packet; vis_packet = (struct batadv_vis_packet *)skb->data; memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN); diff --git a/main.h b/main.h index 9186e5d..8cd4277 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 BATADV_DAT_CANDIDATES_NUM 3 + #define BATADV_VIS_INTERVAL 5000 /* 5 seconds */
/* how much worse secondary interfaces may be to be considered as bonding @@ -118,6 +121,9 @@ enum batadv_uev_type {
#define BATADV_GW_THRESHOLD 50
+#define BATADV_DAT_CANDIDATE_NOT_FOUND 0 +#define BATADV_DAT_CANDIDATE_ORIG 1 + /* Debug Messages */ #ifdef pr_fmt #undef pr_fmt diff --git a/originator.c b/originator.c index d9c14b8..84930a4 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_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 02d5f50..27e3358 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_bat_iv - per hard interface B.A.T.M.A.N. IV data * @ogm_buff: buffer holding the OGM packet @@ -73,6 +80,7 @@ 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 dat_addr; unsigned long *bcast_own; uint8_t *bcast_own_sum; unsigned long last_seen; @@ -236,6 +244,14 @@ struct batadv_priv_vis { struct batadv_vis_info *my_info; };
+/** + * struct batadv_priv_dat - per mesh interface DAT private data + * @addr: node DAT address + */ +struct batadv_priv_dat { + batadv_dat_addr_t addr; +}; + struct batadv_priv { atomic_t mesh_state; struct net_device_stats stats; @@ -273,6 +289,7 @@ struct batadv_priv { struct batadv_priv_gw gw; struct batadv_priv_tt tt; struct batadv_priv_vis vis; + struct batadv_priv_dat dat; };
struct batadv_socket_client { @@ -446,4 +463,17 @@ struct batadv_algo_ops { void (*bat_ogm_emit)(struct batadv_forw_packet *forw_packet); };
+/** + * struct batadv_dat_candidate - candidate destination for DAT operations + * @type: the type of the selected candidate. It can one of the following: + * - BATADV_DAT_CANDIDATE_NOT_FOUND + * - BATADV_DAT_CANDIDATE_ORIG + * @orig_node: if type is BATADV_DAT_CANDIDATE_ORIG this field points to the + * corresponding originator node structure + */ +struct batadv_dat_candidate { + int type; + struct batadv_orig_node *orig_node; +}; + #endif /* _NET_BATMAN_ADV_TYPES_H_ */ diff --git a/unicast.c b/unicast.c index 1df22c5..1ebf533 100644 --- a/unicast.c +++ b/unicast.c @@ -347,10 +347,10 @@ static bool batadv_unicast_prepare_skb(struct sk_buff *skb, * * Returns false if the payload could not be encapsulated or true otherwise */ -static bool batadv_unicast_4addr_prepare_skb(struct batadv_priv *bat_priv, - struct sk_buff *skb, - struct batadv_orig_node *orig, - int packet_subtype) +bool batadv_unicast_4addr_prepare_skb(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 a88ed29..61abba5 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_unicast_4addr_prepare_skb(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 batadv_priv *bat_priv, struct sk_buff *skb, int packet_type, int packet_subtype);