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);

In case of an ARP message going in or out the soft_iface, it is intercepted and a special action is performed. In particular the DHT helper functions previously implemented are used to store all the ARP entries belonging to the network in order to provide a fast and unicast lookup instead of the classic broadcast flooding mechanism. Each node stores the entries it is responsible for (following the DHT rules) in its soft_iface ARP table. This makes it possible to reuse the kernel data structures and functions for ARP management.

Signed-off-by: Antonio Quartulli ordex@autistici.org --- distributed-arp-table.c | 246 +++++++++++++++++++++++++++++++++++++++++++++++ distributed-arp-table.h | 11 ++ main.h | 2 + send.c | 6 + soft-interface.c | 18 ++++- 5 files changed, 282 insertions(+), 1 deletions(-)

diff --git a/distributed-arp-table.c b/distributed-arp-table.c index 84e4630..3693879 100644 --- a/distributed-arp-table.c +++ b/distributed-arp-table.c @@ -21,6 +21,8 @@

#include <linux/if_ether.h> #include <linux/if_arp.h> +/* needed to use arp_tbl */ +#include <net/arp.h>

#include "main.h" #include "distributed-arp-table.h" @@ -28,6 +30,7 @@ #include "originator.h" #include "send.h" #include "types.h" +#include "translation-table.h" #include "unicast.h"

#ifdef CONFIG_BATMAN_ADV_DEBUG @@ -276,6 +279,31 @@ out: return ret; }

+/* Update the neighbour entry corresponding to the IP passed as parameter with + * the hw address hw. If the neighbour entry doesn't exists, then it will be + * created */ +static void arp_neigh_update(struct bat_priv *bat_priv, uint32_t ip, + uint8_t *hw) +{ + struct neighbour *n = NULL; + struct hard_iface *primary_if = primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + + n = __neigh_lookup(&arp_tbl, &ip, primary_if->soft_iface, 1); + if (!n) + goto out; + + bat_dbg(DBG_ARP, bat_priv, "Updating neighbour: %pI4 - %pM\n", &ip, hw); + + neigh_update(n, hw, NUD_REACHABLE, NEIGH_UPDATE_F_OVERRIDE); +out: + if (n && !IS_ERR(n)) + neigh_release(n); + if (primary_if) + hardif_free_ref(primary_if); +} + /* Returns arphdr->ar_op if the skb contains a valid ARP packet, otherwise * returns 0 */ static uint16_t arp_get_type(struct bat_priv *bat_priv, struct sk_buff *skb, @@ -327,3 +355,221 @@ static uint16_t arp_get_type(struct bat_priv *bat_priv, struct sk_buff *skb, out: return type; } + +/* return true if the message has been sent to the dht candidates, false + * otherwise. In case of true the message has to be enqueued to permit the + * fallback */ +bool dat_snoop_outgoing_arp_request(struct bat_priv *bat_priv, + struct sk_buff *skb) +{ + uint16_t type = 0; + uint32_t ip_dst, ip_src; + uint8_t *hw_src; + bool ret = false; + struct neighbour *n = NULL; + struct hard_iface *primary_if = NULL; + struct sk_buff *skb_new; + + type = arp_get_type(bat_priv, skb, 0); + /* If we get an ARP_REQUEST we have to send the unicast message to the + * selected DHT candidates */ + if (type != ARPOP_REQUEST) + goto out; + + bat_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REQUEST"); + + ip_src = ARP_IP_SRC(skb, 0); + hw_src = ARP_HW_SRC(skb, 0); + ip_dst = ARP_IP_DST(skb, 0); + + primary_if = primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + + arp_neigh_update(bat_priv, ip_src, hw_src); + + n = neigh_lookup(&arp_tbl, &ip_dst, primary_if->soft_iface); + /* check if it is a valid neigh entry */ + if (n && (n->nud_state & NUD_CONNECTED)) { + skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, + primary_if->soft_iface, ip_dst, hw_src, + n->ha, hw_src); + if (!skb_new) + goto out; + + skb_reset_mac_header(skb_new); + skb_new->protocol = eth_type_trans(skb_new, + primary_if->soft_iface); + bat_priv->stats.rx_packets++; + bat_priv->stats.rx_bytes += skb->len + ETH_HLEN; + primary_if->soft_iface->last_rx = jiffies; + + netif_rx(skb_new); + bat_dbg(DBG_ARP, bat_priv, "ARP request replied locally\n"); + } else + /* Send the request on the DHT */ + ret = dht_send_data(bat_priv, skb, ip_dst, BAT_P_DAT_DHT_GET); +out: + if (n) + neigh_release(n); + if (primary_if) + hardif_free_ref(primary_if); + return ret; +} + +/* This function is meant to be invoked for an ARP request which is coming into + * the bat0 interfaces from the mesh network. It will check for the needed data + * into the local table. If found, an ARP reply is sent immediately, otherwise + * the caller has to deliver the ARP request to the upper layer */ +bool dat_snoop_incoming_arp_request(struct bat_priv *bat_priv, + struct sk_buff *skb, int hdr_size) +{ + uint16_t type; + uint32_t ip_src, ip_dst; + uint8_t *hw_src; + struct hard_iface *primary_if = NULL; + struct sk_buff *skb_new; + struct neighbour *n = NULL; + bool ret = false; + + type = arp_get_type(bat_priv, skb, hdr_size); + if (type != ARPOP_REQUEST) + goto out; + + hw_src = ARP_HW_SRC(skb, hdr_size); + ip_src = ARP_IP_SRC(skb, hdr_size); + ip_dst = ARP_IP_DST(skb, hdr_size); + + bat_dbg_arp(bat_priv, skb, type, hdr_size, + "Parsing incoming ARP REQUEST"); + + primary_if = primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + + arp_neigh_update(bat_priv, ip_src, hw_src); + + n = neigh_lookup(&arp_tbl, &ip_dst, primary_if->soft_iface); + /* check if it is a valid neigh entry */ + if (!n || !(n->nud_state & NUD_CONNECTED)) + goto out; + + skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, + primary_if->soft_iface, ip_dst, hw_src, n->ha, + hw_src); + + if (!skb_new) + goto out; + + unicast_4addr_send_skb(skb_new, bat_priv, BAT_P_DAT_CACHE_REPLY); + + ret = true; +out: + if (n) + neigh_release(n); + if (primary_if) + hardif_free_ref(primary_if); + if (ret) + kfree_skb(skb); + return ret; +} + +/* This function is meant to be invoked on an ARP reply packet going into the + * soft interface. The related neighbour entry has to be updated and the DHT has + * to be populated as well */ +bool dat_snoop_outgoing_arp_reply(struct bat_priv *bat_priv, + struct sk_buff *skb) +{ + uint16_t type; + uint32_t ip_src, ip_dst; + uint8_t *hw_src, *hw_dst; + bool ret = false; + + type = arp_get_type(bat_priv, skb, 0); + if (type != ARPOP_REPLY) + goto out; + + bat_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REPLY"); + + hw_src = ARP_HW_SRC(skb, 0); + ip_src = ARP_IP_SRC(skb, 0); + hw_dst = ARP_HW_DST(skb, 0); + ip_dst = ARP_IP_DST(skb, 0); + + arp_neigh_update(bat_priv, ip_src, hw_src); + arp_neigh_update(bat_priv, ip_dst, hw_dst); + + /* Send the ARP reply to the candidates for both the IP addresses we + * fetched from the ARP reply */ + dht_send_data(bat_priv, skb, ip_src, BAT_P_DAT_DHT_PUT); + dht_send_data(bat_priv, skb, ip_dst, BAT_P_DAT_DHT_PUT); + ret = true; +out: + return ret; +} + +/* This function has to be invoked on an ARP reply coming into the soft + * interface from the mesh network. The local table has to be updated */ +bool dat_snoop_incoming_arp_reply(struct bat_priv *bat_priv, + struct sk_buff *skb, int hdr_size) +{ + uint16_t type; + uint32_t ip_src, ip_dst; + uint8_t *hw_src, *hw_dst; + bool ret = false; + + type = arp_get_type(bat_priv, skb, hdr_size); + if (type != ARPOP_REPLY) + goto out; + + bat_dbg_arp(bat_priv, skb, type, hdr_size, + "Parsing incoming ARP REPLY"); + + hw_src = ARP_HW_SRC(skb, hdr_size); + ip_src = ARP_IP_SRC(skb, hdr_size); + hw_dst = ARP_HW_DST(skb, hdr_size); + ip_dst = ARP_IP_DST(skb, hdr_size); + + /* Update our internal cache with both the IP addresses we fetched from + * the ARP reply */ + arp_neigh_update(bat_priv, ip_src, hw_src); + arp_neigh_update(bat_priv, ip_dst, hw_dst); + + /* if this REPLY is directed to a client of mine, let's deliver the + * packet to the interface */ + ret = !is_my_client(bat_priv, hw_dst); +out: + /* if ret == false packet has to be delivered to the interface */ + return ret; +} + +bool arp_drop_broadcast_packet(struct bat_priv *bat_priv, + struct forw_packet *forw_packet) +{ + struct neighbour *n; + + /* If this packet is an ARP_REQUEST and we already have the information + * that it is going to ask, we can drop the packet */ + if (!forw_packet->num_packets && + (arp_get_type(bat_priv, forw_packet->skb, + sizeof(struct bcast_packet)) == + ARPOP_REQUEST)) { + n = neigh_lookup(&arp_tbl, + &ARP_IP_DST(forw_packet->skb, + sizeof(struct bcast_packet)), + forw_packet->if_incoming->soft_iface); + /* check if we already know this neigh */ + if (n && (n->nud_state & NUD_CONNECTED)) { + bat_dbg(DBG_ARP, bat_priv, "ARP Request for %pI4: " + "fallback prevented\n", + &ARP_IP_DST(forw_packet->skb, + sizeof(struct bcast_packet))); + return true; + } + + bat_dbg(DBG_ARP, bat_priv, "ARP Request for %pI4: fallback\n", + &ARP_IP_DST(forw_packet->skb, + sizeof(struct bcast_packet))); + } + return false; +} diff --git a/distributed-arp-table.h b/distributed-arp-table.h index b5bf2d1..3b90b73 100644 --- a/distributed-arp-table.h +++ b/distributed-arp-table.h @@ -37,6 +37,17 @@ #define ARP_IP_DST(skb, hdr_size) (*(uint32_t *)(ARP_HW_SRC(skb, hdr_size) + \ ETH_ALEN * 2 + 4))

+bool dat_snoop_outgoing_arp_request(struct bat_priv *bat_priv, + struct sk_buff *skb); +bool dat_snoop_incoming_arp_request(struct bat_priv *bat_priv, + struct sk_buff *skb, int hdr_size); +bool dat_snoop_outgoing_arp_reply(struct bat_priv *bat_priv, + struct sk_buff *skb); +bool dat_snoop_incoming_arp_reply(struct bat_priv *bat_priv, + struct sk_buff *skb, int hdr_size); +bool arp_drop_broadcast_packet(struct bat_priv *bat_priv, + struct forw_packet *forw_packet); + /* 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) diff --git a/main.h b/main.h index 86a3d4a..7384abb 100644 --- a/main.h +++ b/main.h @@ -67,6 +67,8 @@

#define NUM_WORDS BITS_TO_LONGS(TQ_LOCAL_WINDOW_SIZE)

+/* msecs after which an ARP_REQUEST is sent in broadcast as fallback */ +#define ARP_REQ_DELAY 250 /* numbers of originator to contact for any PUT/GET DHT operation */ #define DHT_CANDIDATES_NUM 3

diff --git a/send.c b/send.c index 1d5353f..8bd31bb 100644 --- a/send.c +++ b/send.c @@ -20,6 +20,7 @@ */

#include "main.h" +#include "distributed-arp-table.h" #include "send.h" #include "routing.h" #include "translation-table.h" @@ -29,6 +30,8 @@ #include "gateway_common.h" #include "originator.h"

+#include <net/arp.h> + static void send_outstanding_bcast_packet(struct work_struct *work);

/* send out an already prepared packet to the given address via the @@ -274,6 +277,9 @@ static void send_outstanding_bcast_packet(struct work_struct *work) if (atomic_read(&bat_priv->mesh_state) == MESH_DEACTIVATING) goto out;

+ if (arp_drop_broadcast_packet(bat_priv, forw_packet)) + goto out; + /* rebroadcast packet */ rcu_read_lock(); list_for_each_entry_rcu(hard_iface, &hardif_list, list) { diff --git a/soft-interface.c b/soft-interface.c index 3297c40..f27ea7e 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -22,6 +22,7 @@ #include "main.h" #include "soft-interface.h" #include "hard-interface.h" +#include "distributed-arp-table.h" #include "routing.h" #include "send.h" #include "bat_debugfs.h" @@ -136,6 +137,7 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface) int data_len = skb->len, ret; short vid __maybe_unused = -1; bool do_bcast = false; + unsigned long brd_delay = 1;

if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE) goto dropped; @@ -196,6 +198,9 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface) if (!primary_if) goto dropped;

+ if (dat_snoop_outgoing_arp_request(bat_priv, skb)) + brd_delay = msecs_to_jiffies(ARP_REQ_DELAY); + if (my_skb_head_push(skb, sizeof(*bcast_packet)) < 0) goto dropped;

@@ -215,7 +220,7 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface) bcast_packet->seqno = htonl(atomic_inc_return(&bat_priv->bcast_seqno));

- add_bcast_packet_to_list(bat_priv, skb, 1); + add_bcast_packet_to_list(bat_priv, skb, brd_delay);

/* a copy is stored in the bcast list, therefore removing * the original skb. */ @@ -229,6 +234,8 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface) goto dropped; }

+ dat_snoop_outgoing_arp_reply(bat_priv, skb); + ret = unicast_send_skb(skb, bat_priv); if (ret != 0) goto dropped_freed; @@ -253,6 +260,7 @@ void interface_rx(struct net_device *soft_iface, int hdr_size) { struct bat_priv *bat_priv = netdev_priv(soft_iface); + struct unicast_4addr_packet *unicast_4addr_packet; struct ethhdr *ethhdr; struct vlan_ethhdr *vhdr; short vid __maybe_unused = -1; @@ -261,6 +269,14 @@ void interface_rx(struct net_device *soft_iface, if (!pskb_may_pull(skb, hdr_size)) goto dropped;

+ unicast_4addr_packet = (struct unicast_4addr_packet *)skb->data; + + if (dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size)) + goto out; + + if (dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size)) + goto out; + skb_pull_rcsum(skb, hdr_size); skb_reset_mac_header(skb);

This patch makes it possible to decide whether to include DAT within the batman-adv binary or not. It is extremely useful when the user wants to reduce the size of the resulting module by cutting off any not needed feature.

Signed-off-by: Antonio Quartulli ordex@autistici.org --- Makefile | 2 ++ Makefile.kbuild | 2 +- README.external | 1 + distributed-arp-table.h | 15 +++++++++++++++ gen-compat-autoconf.sh | 1 + send.c | 2 -- types.h | 8 ++++++++ 7 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile index 08f8c39..ac84fba 100644 --- a/Makefile +++ b/Makefile @@ -23,6 +23,8 @@ export CONFIG_BATMAN_ADV_DEBUG=n # B.A.T.M.A.N. bridge loop avoidance: export CONFIG_BATMAN_ADV_BLA=y +# B.A.T.M.A.N. distributed ARP table: +export CONFIG_BATMAN_ADV_DAT=y

PWD:=$(shell pwd) KERNELPATH ?= /lib/modules/$(shell uname -r)/build diff --git a/Makefile.kbuild b/Makefile.kbuild index 84955b3..ad002cd 100644 --- a/Makefile.kbuild +++ b/Makefile.kbuild @@ -24,7 +24,7 @@ batman-adv-y += bat_iv_ogm.o batman-adv-y += bat_sysfs.o batman-adv-y += bitarray.o batman-adv-$(CONFIG_BATMAN_ADV_BLA) += bridge_loop_avoidance.o -batman-adv-y += distributed-arp-table.o +batman-adv-$(CONFIG_BATMAN_ADV_DAT) += 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/README.external b/README.external index 1eff0f9..95a7eb4 100644 --- a/README.external +++ b/README.external @@ -37,6 +37,7 @@ module). Available options and their possible values are

* CONFIG_BATMAN_ADV_DEBUG=[y|n*] (B.A.T.M.A.N. debugging) * CONFIG_BATMAN_ADV_BLA=[y*|n] (B.A.T.M.A.N. bridge loop avoidance) + * CONFIG_BATMAN_ADV_DAT=[y*|n] (B.A.T.M.A.N. Distributed ARP Table)

e.g., debugging can be enabled by

diff --git a/distributed-arp-table.h b/distributed-arp-table.h index bf4390d..2e37e3f 100644 --- a/distributed-arp-table.h +++ b/distributed-arp-table.h @@ -22,6 +22,8 @@ #ifndef _NET_BATMAN_ADV_ARP_H_ #define _NET_BATMAN_ADV_ARP_H_

+#ifdef CONFIG_BATMAN_ADV_DAT + #include "types.h" #include "originator.h"

@@ -84,4 +86,17 @@ static inline void dat_init_own_dht_addr(struct bat_priv *bat_priv, DAT_ADDR_MAX); }

+#else + +#define dat_snoop_outgoing_arp_request(...) (0) +#define dat_snoop_incoming_arp_request(...) (0) +#define dat_snoop_outgoing_arp_reply(...) +#define dat_snoop_incoming_arp_reply(...) (0) +#define arp_drop_broadcast_packet(...) (0) +#define arp_change_timeout(...) +#define dat_init_orig_node_dht_addr(...) +#define dat_init_own_dht_addr(...) + +#endif /* CONFIG_BATMAN_ADV_DAT */ + #endif /* _NET_BATMAN_ADV_ARP_H_ */ diff --git a/gen-compat-autoconf.sh b/gen-compat-autoconf.sh index 7cf621b..33de95d 100755 --- a/gen-compat-autoconf.sh +++ b/gen-compat-autoconf.sh @@ -38,6 +38,7 @@ gen_config() { # write config variables gen_config 'CONFIG_BATMAN_ADV_DEBUG' ${CONFIG_BATMAN_ADV_DEBUG:="n"} >> "${TMP}" gen_config 'CONFIG_BATMAN_ADV_BLA' ${CONFIG_BATMAN_ADV_BLA:="y"} >> "${TMP}" +gen_config 'CONFIG_BATMAN_ADV_DAT' ${CONFIG_BATMAN_ADV_DAT:="n"} >> "${TMP}"

# only regenerate compat-autoconf.h when config was changed diff "${TMP}" "${TARGET}" > /dev/null 2>&1 || cp "${TMP}" "${TARGET}" diff --git a/send.c b/send.c index 8bd31bb..65c13b2 100644 --- a/send.c +++ b/send.c @@ -30,8 +30,6 @@ #include "gateway_common.h" #include "originator.h"

-#include <net/arp.h> - static void send_outstanding_bcast_packet(struct work_struct *work);

/* send out an already prepared packet to the given address via the diff --git a/types.h b/types.h index 210ee3e..6a3cc88 100644 --- a/types.h +++ b/types.h @@ -27,6 +27,8 @@ #include "packet.h" #include "bitarray.h"

+#ifdef CONFIG_BATMAN_ADV_DAT + /* * dat_addr_t is the type used for all DHT addresses. If it is changed, * DAT_ADDR_MAX is changed as well. @@ -35,6 +37,8 @@ */ #define dat_addr_t uint16_t

+#endif /* CONFIG_BATMAN_ADV_DAT */ + #define BAT_HEADER_LEN (ETH_HLEN + \ ((sizeof(struct unicast_packet) > sizeof(struct bcast_packet) ? \ sizeof(struct unicast_packet) : \ @@ -75,7 +79,9 @@ struct hard_iface { struct orig_node { uint8_t orig[ETH_ALEN]; uint8_t primary_addr[ETH_ALEN]; +#ifdef CONFIG_BATMAN_ADV_DAT dat_addr_t dht_addr; +#endif struct neigh_node __rcu *router; /* rcu protected pointer */ unsigned long *bcast_own; uint8_t *bcast_own_sum; @@ -230,7 +236,9 @@ 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 */ +#ifdef CONFIG_BATMAN_ADV_DAT dat_addr_t dht_addr; +#endif struct vis_info *my_vis_info; struct bat_algo_ops *bat_algo_ops; };