/* Copyright (C) 2011-2015 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, see . */ #include "distributed-arp-table.h" #include "main.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "hard-interface.h" #include "hash.h" #include "originator.h" #include "send.h" #include "translation-table.h" static void batadv_dat_purge(struct work_struct *work); /** * batadv_dat_start_timer - initialise the DAT periodic worker * @bat_priv: the bat priv with all the soft interface information */ static void batadv_dat_start_timer(struct batadv_priv *bat_priv) { INIT_DELAYED_WORK(&bat_priv->dat.work, batadv_dat_purge); queue_delayed_work(batadv_event_workqueue, &bat_priv->dat.work, msecs_to_jiffies(10000)); } /** * batadv_dat_entry_free_ref - decrement the dat_entry refcounter and possibly * free it * @dat_entry: the entry to free */ static void batadv_dat_entry_free_ref(struct batadv_dat_entry *dat_entry) { if (atomic_dec_and_test(&dat_entry->refcount)) kfree_rcu(dat_entry, rcu); } /** * batadv_dat_to_purge - check whether a dat_entry has to be purged or not * @dat_entry: the entry to check * * Returns true if the entry has to be purged now, false otherwise. */ static bool batadv_dat_to_purge(struct batadv_dat_entry *dat_entry) { return batadv_has_timed_out(dat_entry->last_update, BATADV_DAT_ENTRY_TIMEOUT); } /** * __batadv_dat_purge - delete entries from the DAT local storage * @bat_priv: the bat priv with all the soft interface information * @to_purge: function in charge to decide whether an entry has to be purged or * not. This function takes the dat_entry as argument and has to * returns a boolean value: true is the entry has to be deleted, * false otherwise * * Loops over each entry in the DAT local storage and deletes it if and only if * the to_purge function passed as argument returns true. */ static void __batadv_dat_purge(struct batadv_priv *bat_priv, bool (*to_purge)(struct batadv_dat_entry *)) { spinlock_t *list_lock; /* protects write access to the hash lists */ struct batadv_dat_entry *dat_entry; struct hlist_node *node_tmp; struct hlist_head *head; u32 i; if (!bat_priv->dat.hash) return; for (i = 0; i < bat_priv->dat.hash->size; i++) { head = &bat_priv->dat.hash->table[i]; list_lock = &bat_priv->dat.hash->list_locks[i]; spin_lock_bh(list_lock); hlist_for_each_entry_safe(dat_entry, node_tmp, head, hash_entry) { /* if a helper function has been passed as parameter, * ask it if the entry has to be purged or not */ if (to_purge && !to_purge(dat_entry)) continue; hlist_del_rcu(&dat_entry->hash_entry); batadv_dat_entry_free_ref(dat_entry); } spin_unlock_bh(list_lock); } } /** * batadv_dat_purge - periodic task that deletes old entries from the local DAT * hash table * @work: kernel work struct */ static void batadv_dat_purge(struct work_struct *work) { struct delayed_work *delayed_work; struct batadv_priv_dat *priv_dat; struct batadv_priv *bat_priv; delayed_work = container_of(work, struct delayed_work, work); priv_dat = container_of(delayed_work, struct batadv_priv_dat, work); bat_priv = container_of(priv_dat, struct batadv_priv, dat); __batadv_dat_purge(bat_priv, batadv_dat_to_purge); batadv_dat_start_timer(bat_priv); } /** * batadv_compare_dat - comparing function used in the local DAT hash table * @node: node in the local table * @data2: second object to compare the node to * * Returns 1 if the two entries are the same, 0 otherwise. */ static int batadv_compare_dat(const struct hlist_node *node, const void *data2) { const void *data1 = container_of(node, struct batadv_dat_entry, hash_entry); return memcmp(data1, data2, sizeof(__be32)) == 0 ? 1 : 0; } /** * batadv_arp_hw_src - extract the hw_src field from an ARP packet * @skb: ARP packet * @hdr_size: size of the possible header before the ARP packet * * Returns the value of the hw_src field in the ARP packet. */ static u8 *batadv_arp_hw_src(struct sk_buff *skb, int hdr_size) { u8 *addr; addr = (u8 *)(skb->data + hdr_size); addr += ETH_HLEN + sizeof(struct arphdr); return addr; } /** * batadv_arp_ip_src - extract the ip_src field from an ARP packet * @skb: ARP packet * @hdr_size: size of the possible header before the ARP packet * * Returns the value of the ip_src field in the ARP packet. */ static __be32 batadv_arp_ip_src(struct sk_buff *skb, int hdr_size) { return *(__be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN); } /** * batadv_arp_hw_dst - extract the hw_dst field from an ARP packet * @skb: ARP packet * @hdr_size: size of the possible header before the ARP packet * * Returns the value of the hw_dst field in the ARP packet. */ static u8 *batadv_arp_hw_dst(struct sk_buff *skb, int hdr_size) { return batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN + 4; } /** * batadv_arp_ip_dst - extract the ip_dst field from an ARP packet * @skb: ARP packet * @hdr_size: size of the possible header before the ARP packet * * Returns the value of the ip_dst field in the ARP packet. */ static __be32 batadv_arp_ip_dst(struct sk_buff *skb, int hdr_size) { return *(__be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN * 2 + 4); } /** * 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 u32 batadv_hash_dat(const void *data, u32 size) { u32 hash = 0; const struct batadv_dat_entry *dat = data; const unsigned char *key; u32 i; key = (const unsigned char *)&dat->ip; for (i = 0; i < sizeof(dat->ip); i++) { hash += key[i]; hash += (hash << 10); hash ^= (hash >> 6); } key = (const unsigned char *)&dat->vid; for (i = 0; i < sizeof(dat->vid); i++) { hash += key[i]; hash += (hash << 10); hash ^= (hash >> 6); } hash += (hash << 3); hash ^= (hash >> 11); hash += (hash << 15); return hash % size; } /** * batadv_dat_entry_hash_find - look for a given dat_entry in the local hash * table * @bat_priv: the bat priv with all the soft interface information * @ip: search key * @vid: VLAN identifier * * Returns the dat_entry if found, NULL otherwise. */ static struct batadv_dat_entry * batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip, unsigned short vid) { struct hlist_head *head; struct batadv_dat_entry to_find, *dat_entry, *dat_entry_tmp = NULL; struct batadv_hashtable *hash = bat_priv->dat.hash; u32 index; if (!hash) return NULL; to_find.ip = ip; to_find.vid = vid; index = batadv_hash_dat(&to_find, hash->size); head = &hash->table[index]; rcu_read_lock(); hlist_for_each_entry_rcu(dat_entry, head, hash_entry) { if (dat_entry->ip != ip) continue; if (!atomic_inc_not_zero(&dat_entry->refcount)) continue; dat_entry_tmp = dat_entry; break; } rcu_read_unlock(); return dat_entry_tmp; } /** * batadv_dat_entry_add - add a new dat entry or update it if already exists * @bat_priv: the bat priv with all the soft interface information * @ip: ipv4 to add/edit * @mac_addr: mac address to assign to the given ipv4 * @vid: VLAN identifier */ static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip, u8 *mac_addr, unsigned short vid) { struct batadv_dat_entry *dat_entry; int hash_added; dat_entry = batadv_dat_entry_hash_find(bat_priv, ip, vid); /* if this entry is already known, just update it */ if (dat_entry) { if (!batadv_compare_eth(dat_entry->mac_addr, mac_addr)) ether_addr_copy(dat_entry->mac_addr, mac_addr); dat_entry->last_update = jiffies; batadv_dbg(BATADV_DBG_DAT, bat_priv, "Entry updated: %pI4 %pM (vid: %d)\n", &dat_entry->ip, dat_entry->mac_addr, BATADV_PRINT_VID(vid)); goto out; } dat_entry = kmalloc(sizeof(*dat_entry), GFP_ATOMIC); if (!dat_entry) goto out; dat_entry->ip = ip; dat_entry->vid = vid; ether_addr_copy(dat_entry->mac_addr, mac_addr); dat_entry->last_update = jiffies; atomic_set(&dat_entry->refcount, 2); hash_added = batadv_hash_add(bat_priv->dat.hash, batadv_compare_dat, batadv_hash_dat, dat_entry, &dat_entry->hash_entry); if (unlikely(hash_added != 0)) { /* remove the reference for the hash */ batadv_dat_entry_free_ref(dat_entry); goto out; } batadv_dbg(BATADV_DBG_DAT, bat_priv, "New entry added: %pI4 %pM (vid: %d)\n", &dat_entry->ip, dat_entry->mac_addr, BATADV_PRINT_VID(vid)); out: if (dat_entry) batadv_dat_entry_free_ref(dat_entry); } #ifdef CONFIG_BATMAN_ADV_DEBUG /** * batadv_dbg_arp - print a debug message containing all the ARP packet details * @bat_priv: the bat priv with all the soft interface information * @skb: ARP packet * @type: ARP type * @hdr_size: size of the possible header before the ARP packet * @msg: message to print together with the debugging information */ static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb, u16 type, int hdr_size, char *msg) { struct batadv_unicast_4addr_packet *unicast_4addr_packet; struct batadv_bcast_packet *bcast_pkt; u8 *orig_addr; __be32 ip_src, ip_dst; if (msg) batadv_dbg(BATADV_DBG_DAT, bat_priv, "%s\n", msg); ip_src = batadv_arp_ip_src(skb, hdr_size); ip_dst = batadv_arp_ip_dst(skb, hdr_size); batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]\n", batadv_arp_hw_src(skb, hdr_size), &ip_src, batadv_arp_hw_dst(skb, hdr_size), &ip_dst); if (hdr_size == 0) return; unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data; switch (unicast_4addr_packet->u.packet_type) { case BATADV_UNICAST: batadv_dbg(BATADV_DBG_DAT, bat_priv, "* encapsulated within a UNICAST packet\n"); break; case BATADV_UNICAST_4ADDR: batadv_dbg(BATADV_DBG_DAT, bat_priv, "* encapsulated within a UNICAST_4ADDR packet (src: %pM)\n", unicast_4addr_packet->src); switch (unicast_4addr_packet->subtype) { case BATADV_P_DAT_DHT_PUT: batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_PUT\n"); break; case BATADV_P_DAT_DHT_GET: batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_GET\n"); break; case BATADV_P_DAT_CACHE_REPLY: batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_CACHE_REPLY\n"); break; case BATADV_P_DATA: batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DATA\n"); break; default: batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: Unknown (%u)!\n", unicast_4addr_packet->u.packet_type); } break; case BATADV_BCAST: bcast_pkt = (struct batadv_bcast_packet *)unicast_4addr_packet; orig_addr = bcast_pkt->orig; batadv_dbg(BATADV_DBG_DAT, bat_priv, "* encapsulated within a BCAST packet (src: %pM)\n", orig_addr); break; default: batadv_dbg(BATADV_DBG_DAT, bat_priv, "* encapsulated within an unknown packet type (0x%x)\n", unicast_4addr_packet->u.packet_type); } } #else static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb, u16 type, int hdr_size, char *msg) { } #endif /* CONFIG_BATMAN_ADV_DEBUG */ /** * 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 * otherwise. */ 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 orig node candidate is running DAT */ if (!test_bit(BATADV_ORIG_CAPA_HAS_DAT, &candidate->capabilities)) goto out; /* 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) && max_orig_node && (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; batadv_dat_addr_t tmp_max = 0; struct batadv_orig_node *orig_node, *max_orig_node = NULL; struct batadv_hashtable *hash = bat_priv->orig_hash; 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 the 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, head, hash_entry) { /* the dht space is a ring using unsigned addresses */ 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 - select 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 * @vid: VLAN identifier * * 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, unsigned short vid) { int select; batadv_dat_addr_t last_max = BATADV_DAT_ADDR_MAX, ip_key; struct batadv_dat_candidate *res; struct batadv_dat_entry dat; if (!bat_priv->orig_hash) return NULL; res = kmalloc_array(BATADV_DAT_CANDIDATES_NUM, sizeof(*res), GFP_ATOMIC); if (!res) return NULL; dat.ip = ip_dst; dat.vid = vid; ip_key = (batadv_dat_addr_t)batadv_hash_dat(&dat, 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 * @vid: VLAN identifier * @packet_subtype: unicast4addr packet subtype to use * * This function copies the skb with 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, unsigned short vid, 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, vid); 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_router_get(cand[i].orig_node, BATADV_IF_DEFAULT); if (!neigh_node) goto free_orig; tmp_skb = pskb_copy_for_clone(skb, GFP_ATOMIC); if (!batadv_send_skb_prepare_unicast_4addr(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) { /* count the sent packet */ switch (packet_subtype) { case BATADV_P_DAT_DHT_GET: batadv_inc_counter(bat_priv, BATADV_CNT_DAT_GET_TX); break; case BATADV_P_DAT_DHT_PUT: batadv_inc_counter(bat_priv, BATADV_CNT_DAT_PUT_TX); break; } /* 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; } /** * batadv_dat_tvlv_container_update - update the dat tvlv container after dat * setting change * @bat_priv: the bat priv with all the soft interface information */ static void batadv_dat_tvlv_container_update(struct batadv_priv *bat_priv) { char dat_mode; dat_mode = atomic_read(&bat_priv->distributed_arp_table); switch (dat_mode) { case 0: batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_DAT, 1); break; case 1: batadv_tvlv_container_register(bat_priv, BATADV_TVLV_DAT, 1, NULL, 0); break; } } /** * batadv_dat_status_update - update the dat tvlv container after dat * setting change * @net_dev: the soft interface net device */ void batadv_dat_status_update(struct net_device *net_dev) { struct batadv_priv *bat_priv = netdev_priv(net_dev); batadv_dat_tvlv_container_update(bat_priv); } /** * batadv_gw_tvlv_ogm_handler_v1 - process incoming dat tvlv container * @bat_priv: the bat priv with all the soft interface information * @orig: the orig_node of the ogm * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags) * @tvlv_value: tvlv buffer containing the gateway data * @tvlv_value_len: tvlv buffer length */ static void batadv_dat_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, struct batadv_orig_node *orig, u8 flags, void *tvlv_value, u16 tvlv_value_len) { if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND) clear_bit(BATADV_ORIG_CAPA_HAS_DAT, &orig->capabilities); else set_bit(BATADV_ORIG_CAPA_HAS_DAT, &orig->capabilities); } /** * batadv_dat_hash_free - free the local DAT hash table * @bat_priv: the bat priv with all the soft interface information */ static void batadv_dat_hash_free(struct batadv_priv *bat_priv) { if (!bat_priv->dat.hash) return; __batadv_dat_purge(bat_priv, NULL); batadv_hash_destroy(bat_priv->dat.hash); bat_priv->dat.hash = NULL; } /** * batadv_dat_init - initialise the DAT internals * @bat_priv: the bat priv with all the soft interface information */ int batadv_dat_init(struct batadv_priv *bat_priv) { if (bat_priv->dat.hash) return 0; bat_priv->dat.hash = batadv_hash_new(1024); if (!bat_priv->dat.hash) return -ENOMEM; batadv_dat_start_timer(bat_priv); batadv_tvlv_handler_register(bat_priv, batadv_dat_tvlv_ogm_handler_v1, NULL, BATADV_TVLV_DAT, 1, BATADV_TVLV_HANDLER_OGM_CIFNOTFND); batadv_dat_tvlv_container_update(bat_priv); return 0; } /** * batadv_dat_free - free the DAT internals * @bat_priv: the bat priv with all the soft interface information */ void batadv_dat_free(struct batadv_priv *bat_priv) { batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_DAT, 1); batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_DAT, 1); cancel_delayed_work_sync(&bat_priv->dat.work); batadv_dat_hash_free(bat_priv); } /** * batadv_dat_cache_seq_print_text - print the local DAT hash table * @seq: seq file to print on * @offset: not used */ int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset) { struct net_device *net_dev = (struct net_device *)seq->private; struct batadv_priv *bat_priv = netdev_priv(net_dev); struct batadv_hashtable *hash = bat_priv->dat.hash; struct batadv_dat_entry *dat_entry; struct batadv_hard_iface *primary_if; struct hlist_head *head; unsigned long last_seen_jiffies; int last_seen_msecs, last_seen_secs, last_seen_mins; u32 i; primary_if = batadv_seq_print_text_primary_if_get(seq); if (!primary_if) goto out; seq_printf(seq, "Distributed ARP Table (%s):\n", net_dev->name); seq_printf(seq, " %-7s %-9s %4s %11s\n", "IPv4", "MAC", "VID", "last-seen"); for (i = 0; i < hash->size; i++) { head = &hash->table[i]; rcu_read_lock(); hlist_for_each_entry_rcu(dat_entry, head, hash_entry) { last_seen_jiffies = jiffies - dat_entry->last_update; last_seen_msecs = jiffies_to_msecs(last_seen_jiffies); last_seen_mins = last_seen_msecs / 60000; last_seen_msecs = last_seen_msecs % 60000; last_seen_secs = last_seen_msecs / 1000; seq_printf(seq, " * %15pI4 %14pM %4i %6i:%02i\n", &dat_entry->ip, dat_entry->mac_addr, BATADV_PRINT_VID(dat_entry->vid), last_seen_mins, last_seen_secs); } rcu_read_unlock(); } out: if (primary_if) batadv_hardif_free_ref(primary_if); return 0; } /** * batadv_arp_get_type - parse an ARP packet and gets the type * @bat_priv: the bat priv with all the soft interface information * @skb: packet to analyse * @hdr_size: size of the possible header before the ARP packet in the skb * * Returns the ARP type if the skb contains a valid ARP packet, 0 otherwise. */ static u16 batadv_arp_get_type(struct batadv_priv *bat_priv, struct sk_buff *skb, int hdr_size) { struct arphdr *arphdr; struct ethhdr *ethhdr; __be32 ip_src, ip_dst; u8 *hw_src, *hw_dst; u16 type = 0; /* pull the ethernet header */ if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN))) goto out; ethhdr = (struct ethhdr *)(skb->data + hdr_size); if (ethhdr->h_proto != htons(ETH_P_ARP)) goto out; /* pull the ARP payload */ if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN + arp_hdr_len(skb->dev)))) goto out; arphdr = (struct arphdr *)(skb->data + hdr_size + ETH_HLEN); /* check whether the ARP packet carries a valid IP information */ if (arphdr->ar_hrd != htons(ARPHRD_ETHER)) goto out; if (arphdr->ar_pro != htons(ETH_P_IP)) goto out; if (arphdr->ar_hln != ETH_ALEN) goto out; if (arphdr->ar_pln != 4) goto out; /* Check for bad reply/request. If the ARP message is not sane, DAT * will simply ignore it */ ip_src = batadv_arp_ip_src(skb, hdr_size); ip_dst = batadv_arp_ip_dst(skb, hdr_size); if (ipv4_is_loopback(ip_src) || ipv4_is_multicast(ip_src) || ipv4_is_loopback(ip_dst) || ipv4_is_multicast(ip_dst) || ipv4_is_zeronet(ip_src) || ipv4_is_lbcast(ip_src) || ipv4_is_zeronet(ip_dst) || ipv4_is_lbcast(ip_dst)) goto out; hw_src = batadv_arp_hw_src(skb, hdr_size); if (is_zero_ether_addr(hw_src) || is_multicast_ether_addr(hw_src)) goto out; /* don't care about the destination MAC address in ARP requests */ if (arphdr->ar_op != htons(ARPOP_REQUEST)) { hw_dst = batadv_arp_hw_dst(skb, hdr_size); if (is_zero_ether_addr(hw_dst) || is_multicast_ether_addr(hw_dst)) goto out; } type = ntohs(arphdr->ar_op); out: return type; } /** * batadv_dat_get_vid - extract the VLAN identifier from skb if any * @skb: the buffer containing the packet to extract the VID from * @hdr_size: the size of the batman-adv header encapsulating the packet * * If the packet embedded in the skb is vlan tagged this function returns the * VID with the BATADV_VLAN_HAS_TAG flag. Otherwise BATADV_NO_FLAGS is returned. */ static unsigned short batadv_dat_get_vid(struct sk_buff *skb, int *hdr_size) { unsigned short vid; vid = batadv_get_vid(skb, *hdr_size); /* ARP parsing functions jump forward of hdr_size + ETH_HLEN. * If the header contained in the packet is a VLAN one (which is longer) * hdr_size is updated so that the functions will still skip the * correct amount of bytes. */ if (vid & BATADV_VLAN_HAS_TAG) *hdr_size += VLAN_HLEN; return vid; } /** * batadv_dat_snoop_outgoing_arp_request - snoop the ARP request and try to * answer using DAT * @bat_priv: the bat priv with all the soft interface information * @skb: packet to check * * Returns true if the message has been sent to the dht candidates, false * otherwise. In case of a positive return value the message has to be enqueued * to permit the fallback. */ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv, struct sk_buff *skb) { u16 type = 0; __be32 ip_dst, ip_src; u8 *hw_src; bool ret = false; struct batadv_dat_entry *dat_entry = NULL; struct sk_buff *skb_new; int hdr_size = 0; unsigned short vid; if (!atomic_read(&bat_priv->distributed_arp_table)) goto out; vid = batadv_dat_get_vid(skb, &hdr_size); type = batadv_arp_get_type(bat_priv, skb, hdr_size); /* If the node gets an ARP_REQUEST it has to send a DHT_GET unicast * message to the selected DHT candidates */ if (type != ARPOP_REQUEST) goto out; batadv_dbg_arp(bat_priv, skb, type, hdr_size, "Parsing outgoing ARP REQUEST"); ip_src = batadv_arp_ip_src(skb, hdr_size); hw_src = batadv_arp_hw_src(skb, hdr_size); ip_dst = batadv_arp_ip_dst(skb, hdr_size); batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst, vid); if (dat_entry) { /* If the ARP request is destined for a local client the local * client will answer itself. DAT would only generate a * duplicate packet. * * Moreover, if the soft-interface is enslaved into a bridge, an * additional DAT answer may trigger kernel warnings about * a packet coming from the wrong port. */ if (batadv_is_my_client(bat_priv, dat_entry->mac_addr, vid)) { ret = true; goto out; } skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, bat_priv->soft_iface, ip_dst, hw_src, dat_entry->mac_addr, hw_src); if (!skb_new) goto out; if (vid & BATADV_VLAN_HAS_TAG) skb_new = vlan_insert_tag(skb_new, htons(ETH_P_8021Q), vid & VLAN_VID_MASK); skb_reset_mac_header(skb_new); skb_new->protocol = eth_type_trans(skb_new, bat_priv->soft_iface); bat_priv->stats.rx_packets++; bat_priv->stats.rx_bytes += skb->len + ETH_HLEN + hdr_size; bat_priv->soft_iface->last_rx = jiffies; netif_rx(skb_new); batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP request replied locally\n"); ret = true; } else { /* Send the request to the DHT */ ret = batadv_dat_send_data(bat_priv, skb, ip_dst, vid, BATADV_P_DAT_DHT_GET); } out: if (dat_entry) batadv_dat_entry_free_ref(dat_entry); return ret; } /** * batadv_dat_snoop_incoming_arp_request - snoop the ARP request and try to * answer using the local DAT storage * @bat_priv: the bat priv with all the soft interface information * @skb: packet to check * @hdr_size: size of the encapsulation header * * Returns true if the request has been answered, false otherwise. */ bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv, struct sk_buff *skb, int hdr_size) { u16 type; __be32 ip_src, ip_dst; u8 *hw_src; struct sk_buff *skb_new; struct batadv_dat_entry *dat_entry = NULL; bool ret = false; unsigned short vid; int err; if (!atomic_read(&bat_priv->distributed_arp_table)) goto out; vid = batadv_dat_get_vid(skb, &hdr_size); type = batadv_arp_get_type(bat_priv, skb, hdr_size); if (type != ARPOP_REQUEST) goto out; hw_src = batadv_arp_hw_src(skb, hdr_size); ip_src = batadv_arp_ip_src(skb, hdr_size); ip_dst = batadv_arp_ip_dst(skb, hdr_size); batadv_dbg_arp(bat_priv, skb, type, hdr_size, "Parsing incoming ARP REQUEST"); batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst, vid); if (!dat_entry) goto out; skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, bat_priv->soft_iface, ip_dst, hw_src, dat_entry->mac_addr, hw_src); if (!skb_new) goto out; /* the rest of the TX path assumes that the mac_header offset pointing * to the inner Ethernet header has been set, therefore reset it now. */ skb_reset_mac_header(skb_new); if (vid & BATADV_VLAN_HAS_TAG) skb_new = vlan_insert_tag(skb_new, htons(ETH_P_8021Q), vid & VLAN_VID_MASK); /* To preserve backwards compatibility, the node has choose the outgoing * format based on the incoming request packet type. The assumption is * that a node not using the 4addr packet format doesn't support it. */ if (hdr_size == sizeof(struct batadv_unicast_4addr_packet)) err = batadv_send_skb_via_tt_4addr(bat_priv, skb_new, BATADV_P_DAT_CACHE_REPLY, NULL, vid); else err = batadv_send_skb_via_tt(bat_priv, skb_new, NULL, vid); if (err != NET_XMIT_DROP) { batadv_inc_counter(bat_priv, BATADV_CNT_DAT_CACHED_REPLY_TX); ret = true; } out: if (dat_entry) batadv_dat_entry_free_ref(dat_entry); if (ret) kfree_skb(skb); return ret; } /** * batadv_dat_snoop_outgoing_arp_reply - snoop the ARP reply and fill the DHT * @bat_priv: the bat priv with all the soft interface information * @skb: packet to check */ void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv, struct sk_buff *skb) { u16 type; __be32 ip_src, ip_dst; u8 *hw_src, *hw_dst; int hdr_size = 0; unsigned short vid; if (!atomic_read(&bat_priv->distributed_arp_table)) return; vid = batadv_dat_get_vid(skb, &hdr_size); type = batadv_arp_get_type(bat_priv, skb, hdr_size); if (type != ARPOP_REPLY) return; batadv_dbg_arp(bat_priv, skb, type, hdr_size, "Parsing outgoing ARP REPLY"); hw_src = batadv_arp_hw_src(skb, hdr_size); ip_src = batadv_arp_ip_src(skb, hdr_size); hw_dst = batadv_arp_hw_dst(skb, hdr_size); ip_dst = batadv_arp_ip_dst(skb, hdr_size); batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); batadv_dat_entry_add(bat_priv, ip_dst, hw_dst, vid); /* Send the ARP reply to the candidates for both the IP addresses that * the node obtained from the ARP reply */ batadv_dat_send_data(bat_priv, skb, ip_src, vid, BATADV_P_DAT_DHT_PUT); batadv_dat_send_data(bat_priv, skb, ip_dst, vid, BATADV_P_DAT_DHT_PUT); } /** * batadv_dat_snoop_incoming_arp_reply - snoop the ARP reply and fill the local * DAT storage only * @bat_priv: the bat priv with all the soft interface information * @skb: packet to check * @hdr_size: size of the encapsulation header * * Returns true if the packet was snooped and consumed by DAT. False if the * packet has to be delivered to the interface */ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, struct sk_buff *skb, int hdr_size) { u16 type; __be32 ip_src, ip_dst; u8 *hw_src, *hw_dst; bool dropped = false; unsigned short vid; if (!atomic_read(&bat_priv->distributed_arp_table)) goto out; vid = batadv_dat_get_vid(skb, &hdr_size); type = batadv_arp_get_type(bat_priv, skb, hdr_size); if (type != ARPOP_REPLY) goto out; batadv_dbg_arp(bat_priv, skb, type, hdr_size, "Parsing incoming ARP REPLY"); hw_src = batadv_arp_hw_src(skb, hdr_size); ip_src = batadv_arp_ip_src(skb, hdr_size); hw_dst = batadv_arp_hw_dst(skb, hdr_size); ip_dst = batadv_arp_ip_dst(skb, hdr_size); /* Update our internal cache with both the IP addresses the node got * within the ARP reply */ batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); batadv_dat_entry_add(bat_priv, ip_dst, hw_dst, vid); /* if this REPLY is directed to a client of mine, let's deliver the * packet to the interface */ dropped = !batadv_is_my_client(bat_priv, hw_dst, vid); /* if this REPLY is sent on behalf of a client of mine, let's drop the * packet because the client will reply by itself */ dropped |= batadv_is_my_client(bat_priv, hw_src, vid); out: if (dropped) kfree_skb(skb); /* if dropped == false -> deliver to the interface */ return dropped; } /** * batadv_dat_drop_broadcast_packet - check if an ARP request has to be dropped * (because the node has already obtained the reply via DAT) or not * @bat_priv: the bat priv with all the soft interface information * @forw_packet: the broadcast packet * * Returns true if the node can drop the packet, false otherwise. */ bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv, struct batadv_forw_packet *forw_packet) { u16 type; __be32 ip_dst; struct batadv_dat_entry *dat_entry = NULL; bool ret = false; int hdr_size = sizeof(struct batadv_bcast_packet); unsigned short vid; if (!atomic_read(&bat_priv->distributed_arp_table)) goto out; /* If this packet is an ARP_REQUEST and the node already has the * information that it is going to ask, then the packet can be dropped */ if (forw_packet->num_packets) goto out; vid = batadv_dat_get_vid(forw_packet->skb, &hdr_size); type = batadv_arp_get_type(bat_priv, forw_packet->skb, hdr_size); if (type != ARPOP_REQUEST) goto out; ip_dst = batadv_arp_ip_dst(forw_packet->skb, hdr_size); dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst, vid); /* check if the node already got this entry */ if (!dat_entry) { batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP Request for %pI4: fallback\n", &ip_dst); goto out; } batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP Request for %pI4: fallback prevented\n", &ip_dst); ret = true; out: if (dat_entry) batadv_dat_entry_free_ref(dat_entry); return ret; }