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 | 214 +++++++++++++++++++++++++++++++++++++++++++++++ distributed-arp-table.h | 65 ++++++++++++++ hard-interface.c | 3 + main.h | 7 ++ originator.c | 2 + types.h | 15 ++++ unicast.c | 8 +- unicast.h | 4 + 9 files changed, 315 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 6d5c194..84955b3 100644 --- a/Makefile.kbuild +++ b/Makefile.kbuild @@ -24,6 +24,7 @@ batman-adv-y += bat_iv_ogm.o batman-adv-y += bat_sysfs.o batman-adv-y += bitarray.o batman-adv-$(CONFIG_BATMAN_ADV_BLA) += bridge_loop_avoidance.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..f36b85c --- /dev/null +++ b/distributed-arp-table.c @@ -0,0 +1,214 @@ +/* + * 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" + +static bool is_orig_node_eligible(struct dht_candidate *res, int select, + dat_addr_t tmp_max, dat_addr_t max, + dat_addr_t last_max, + struct orig_node *candidate, + struct 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 && memcmp(candidate->orig, max_orig_node->orig, + ETH_ALEN) > 0) + goto out; + + ret = true; +out: + return ret; +} + + +/* 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. + * + * 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; + dat_addr_t last_max = DAT_ADDR_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 = (dat_addr_t)hash_ipv4(&ip_dst, DAT_ADDR_MAX); + + bat_dbg(DBG_ARP, bat_priv, "dht_select_candidates(): IP=%pI4 " + "hash(IP)=%u\n", &ip_dst, ip_key); + + for (select = 0; select < DHT_CANDIDATES_NUM; select++) { + max = 0; + max_orig_node = NULL; + /* Since the local node is not in the originator list, let's + * first compute its distance from the key and assume it's the + * maximum, then compare it to the other originators. + * If the local node has already been chosen as candidate, jump + * this step */ + if (!chosen_me) { + /* if true, wrap around the key space */ + if (bat_priv->dht_addr > ip_key) + max = DAT_ADDR_MAX - bat_priv->dht_addr + + ip_key; + else + max = ip_key - bat_priv->dht_addr; + res[select].type = DHT_CANDIDATE_ME; + } else + res[select].type = DHT_CANDIDATE_NULL; + /* 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, so we have to check + * if we need to wrap around to compute the + * distance from the key */ + if (orig_node->dht_addr > ip_key) + tmp_max = DAT_ADDR_MAX - + orig_node->dht_addr + ip_key; + else + tmp_max = ip_key - orig_node->dht_addr; + if (!is_orig_node_eligible(res, 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) + 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_select_candidates() %d: " + "selected %pM addr=%u dist=%u\n", select, + max_orig_node->orig, max_orig_node->dht_addr, + max); + } else if (res[select].type == DHT_CANDIDATE_ME) { + chosen_me = true; + bat_dbg(DBG_ARP, bat_priv, "dht_select_candidates() %d: " + "selected ME addr=%u dist=%u\n", select, + bat_priv->dht_addr, max); + } + + 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 packet_subtype) +{ + 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); + if (prepare_unicast_4addr_packet(bat_priv, tmp_skb, + cand[i].orig_node, + packet_subtype)) + send_skb_packet(tmp_skb, neigh_node->if_incoming, + neigh_node->addr); + else + kfree_skb(tmp_skb); + /* 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..89d52c8 --- /dev/null +++ b/distributed-arp-table.h @@ -0,0 +1,65 @@ +/* + * 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_ + +#include "types.h" +#include "originator.h" + +#define DAT_ADDR_MAX biggest_unsigned_int(dat_addr_t) + +/* 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; +} + +static inline void dat_init_orig_node_dht_addr(struct orig_node *orig_node) +{ + orig_node->dht_addr = (dat_addr_t)choose_orig(orig_node->orig, + DAT_ADDR_MAX); +} + +static inline void dat_init_own_dht_addr(struct bat_priv *bat_priv, + struct hard_iface *primary_if) +{ + bat_priv->dht_addr = (dat_addr_t) + choose_orig(primary_if->net_dev->dev_addr, + DAT_ADDR_MAX); +} + +#endif /* _NET_BATMAN_ADV_ARP_H_ */ diff --git a/hard-interface.c b/hard-interface.c index f18459c..77e3163 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -20,6 +20,7 @@ */
#include "main.h" +#include "distributed-arp-table.h" #include "hard-interface.h" #include "soft-interface.h" #include "send.h" @@ -118,6 +119,8 @@ static void primary_if_update_addr(struct bat_priv *bat_priv, if (!primary_if) goto out;
+ dat_init_own_dht_addr(bat_priv, primary_if); + 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 3060f94..86a3d4a 100644 --- a/main.h +++ b/main.h @@ -67,6 +67,9 @@
#define NUM_WORDS BITS_TO_LONGS(TQ_LOCAL_WINDOW_SIZE)
+/* numbers of originator to contact for any PUT/GET DHT operation */ +#define DHT_CANDIDATES_NUM 3 + #define LOG_BUF_LEN 8192 /* has to be a power of 2 */
#define VIS_INTERVAL 5000 /* 5 seconds */ @@ -111,6 +114,10 @@ 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 2db4b53..1ee6e82 100644 --- a/originator.c +++ b/originator.c @@ -20,6 +20,7 @@ */
#include "main.h" +#include "distributed-arp-table.h" #include "originator.h" #include "hash.h" #include "translation-table.h" @@ -224,6 +225,7 @@ 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); + 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 2f4848b..210ee3e 100644 --- a/types.h +++ b/types.h @@ -27,6 +27,14 @@ #include "packet.h" #include "bitarray.h"
+/* + * dat_addr_t is the type used for all DHT addresses. If it is changed, + * DAT_ADDR_MAX is changed as well. + * + * *Please be careful: dat_addr_t must be UNSIGNED* + */ +#define dat_addr_t uint16_t + #define BAT_HEADER_LEN (ETH_HLEN + \ ((sizeof(struct unicast_packet) > sizeof(struct bcast_packet) ? \ sizeof(struct unicast_packet) : \ @@ -67,6 +75,7 @@ struct hard_iface { struct orig_node { uint8_t orig[ETH_ALEN]; uint8_t primary_addr[ETH_ALEN]; + dat_addr_t dht_addr; struct neigh_node __rcu *router; /* rcu protected pointer */ unsigned long *bcast_own; uint8_t *bcast_own_sum; @@ -221,6 +230,7 @@ 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 */ + dat_addr_t dht_addr; struct vis_info *my_vis_info; struct bat_algo_ops *bat_algo_ops; }; @@ -395,4 +405,9 @@ struct bat_algo_ops { struct sk_buff *skb); };
+struct dht_candidate { + int type; + struct orig_node *orig_node; +}; + #endif /* _NET_BATMAN_ADV_TYPES_H_ */ diff --git a/unicast.c b/unicast.c index 18e5cfd..e363a48 100644 --- a/unicast.c +++ b/unicast.c @@ -313,10 +313,10 @@ static bool prepare_unicast_packet(struct sk_buff *skb, orig_node); }
-static bool prepare_unicast_4addr_packet(struct bat_priv *bat_priv, - struct sk_buff *skb, - struct orig_node *orig_node, - int packet_subtype) +bool prepare_unicast_4addr_packet(struct bat_priv *bat_priv, + struct sk_buff *skb, + struct orig_node *orig_node, + int packet_subtype) { struct hard_iface *primary_if; struct unicast_4addr_packet *unicast_4addr_packet; diff --git a/unicast.h b/unicast.h index ae9775b..e15aa62 100644 --- a/unicast.h +++ b/unicast.h @@ -32,6 +32,10 @@ int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv, void frag_list_free(struct list_head *head); int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, struct hard_iface *hard_iface, const uint8_t dstaddr[]); +bool prepare_unicast_4addr_packet(struct bat_priv *bat_priv, + struct sk_buff *skb, + struct orig_node *orig_node, + int packet_subtype); int unicast_generic_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, int packet_type, int packet_subtype);