| // SPDX-License-Identifier: GPL-2.0 |
| /* Copyright (C) B.A.T.M.A.N. contributors: |
| * |
| * Antonio Quartulli |
| */ |
| |
| #include "distributed-arp-table.h" |
| #include "main.h" |
| |
| #include <asm/unaligned.h> |
| #include <linux/atomic.h> |
| #include <linux/bitops.h> |
| #include <linux/byteorder/generic.h> |
| #include <linux/container_of.h> |
| #include <linux/errno.h> |
| #include <linux/etherdevice.h> |
| #include <linux/gfp.h> |
| #include <linux/if_arp.h> |
| #include <linux/if_ether.h> |
| #include <linux/if_vlan.h> |
| #include <linux/in.h> |
| #include <linux/ip.h> |
| #include <linux/jiffies.h> |
| #include <linux/kref.h> |
| #include <linux/list.h> |
| #include <linux/netlink.h> |
| #include <linux/rculist.h> |
| #include <linux/rcupdate.h> |
| #include <linux/skbuff.h> |
| #include <linux/slab.h> |
| #include <linux/spinlock.h> |
| #include <linux/stddef.h> |
| #include <linux/string.h> |
| #include <linux/udp.h> |
| #include <linux/workqueue.h> |
| #include <net/arp.h> |
| #include <net/genetlink.h> |
| #include <net/netlink.h> |
| #include <net/sock.h> |
| #include <uapi/linux/batman_adv.h> |
| |
| #include "bridge_loop_avoidance.h" |
| #include "hard-interface.h" |
| #include "hash.h" |
| #include "log.h" |
| #include "netlink.h" |
| #include "originator.h" |
| #include "send.h" |
| #include "soft-interface.h" |
| #include "translation-table.h" |
| #include "tvlv.h" |
| |
| enum batadv_bootpop { |
| BATADV_BOOTREPLY = 2, |
| }; |
| |
| enum batadv_boothtype { |
| BATADV_HTYPE_ETHERNET = 1, |
| }; |
| |
| enum batadv_dhcpoptioncode { |
| BATADV_DHCP_OPT_PAD = 0, |
| BATADV_DHCP_OPT_MSG_TYPE = 53, |
| BATADV_DHCP_OPT_END = 255, |
| }; |
| |
| enum batadv_dhcptype { |
| BATADV_DHCPACK = 5, |
| }; |
| |
| /* { 99, 130, 83, 99 } */ |
| #define BATADV_DHCP_MAGIC 1669485411 |
| |
| struct batadv_dhcp_packet { |
| __u8 op; |
| __u8 htype; |
| __u8 hlen; |
| __u8 hops; |
| __be32 xid; |
| __be16 secs; |
| __be16 flags; |
| __be32 ciaddr; |
| __be32 yiaddr; |
| __be32 siaddr; |
| __be32 giaddr; |
| __u8 chaddr[16]; |
| __u8 sname[64]; |
| __u8 file[128]; |
| __be32 magic; |
| /* __u8 options[]; */ |
| }; |
| |
| #define BATADV_DHCP_YIADDR_LEN sizeof(((struct batadv_dhcp_packet *)0)->yiaddr) |
| #define BATADV_DHCP_CHADDR_LEN sizeof(((struct batadv_dhcp_packet *)0)->chaddr) |
| |
| 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) |
| { |
| queue_delayed_work(batadv_event_workqueue, &bat_priv->dat.work, |
| msecs_to_jiffies(10000)); |
| } |
| |
| /** |
| * batadv_dat_entry_release() - release dat_entry from lists and queue for free |
| * after rcu grace period |
| * @ref: kref pointer of the dat_entry |
| */ |
| static void batadv_dat_entry_release(struct kref *ref) |
| { |
| struct batadv_dat_entry *dat_entry; |
| |
| dat_entry = container_of(ref, struct batadv_dat_entry, refcount); |
| |
| kfree_rcu(dat_entry, rcu); |
| } |
| |
| /** |
| * batadv_dat_entry_put() - decrement the dat_entry refcounter and possibly |
| * release it |
| * @dat_entry: dat_entry to be free'd |
| */ |
| static void batadv_dat_entry_put(struct batadv_dat_entry *dat_entry) |
| { |
| if (!dat_entry) |
| return; |
| |
| kref_put(&dat_entry->refcount, batadv_dat_entry_release); |
| } |
| |
| /** |
| * batadv_dat_to_purge() - check whether a dat_entry has to be purged or not |
| * @dat_entry: the entry to check |
| * |
| * Return: 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_put(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 = to_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 |
| * |
| * Return: true if the two entries are the same, false otherwise. |
| */ |
| static bool 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; |
| } |
| |
| /** |
| * 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 |
| * |
| * Return: 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 |
| * |
| * Return: 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 *(__force __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 |
| * |
| * Return: 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 |
| * |
| * Return: the value of the ip_dst field in the ARP packet. |
| */ |
| static __be32 batadv_arp_ip_dst(struct sk_buff *skb, int hdr_size) |
| { |
| u8 *dst = batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN * 2 + 4; |
| |
| return *(__force __be32 *)dst; |
| } |
| |
| /** |
| * batadv_hash_dat() - compute the hash value for an IP address |
| * @data: data to hash |
| * @size: size of the hash table |
| * |
| * Return: 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; |
| __be16 vid; |
| u32 i; |
| |
| key = (__force const unsigned char *)&dat->ip; |
| for (i = 0; i < sizeof(dat->ip); i++) { |
| hash += key[i]; |
| hash += (hash << 10); |
| hash ^= (hash >> 6); |
| } |
| |
| vid = htons(dat->vid); |
| key = (__force const unsigned char *)&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 |
| * |
| * Return: 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 (!kref_get_unless_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; |
| kref_init(&dat_entry->refcount); |
| |
| kref_get(&dat_entry->refcount); |
| 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_put(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: |
| batadv_dat_entry_put(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 |
| * @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, |
| 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 < sizeof(struct batadv_unicast_packet)) |
| 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, |
| 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 |
| * |
| * Return: 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)) |
| 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 (!kref_get_unless_zero(&orig_node->refcount)) |
| continue; |
| |
| max = tmp_max; |
| batadv_orig_node_put(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. |
| * |
| * Return: 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, |
| "%s(): IP=%pI4 hash(IP)=%u\n", __func__, &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_forward_data() - copy and send 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 a unicast packet |
| * to each of the selected candidates. |
| * |
| * Return: true if the packet is sent to at least one candidate, false |
| * otherwise. |
| */ |
| static bool batadv_dat_forward_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_unicast_skb(tmp_skb, neigh_node); |
| 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_put(neigh_node); |
| free_orig: |
| batadv_orig_node_put(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_dat_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 |
| * |
| * Return: 0 in case of success, a negative error code otherwise |
| */ |
| 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; |
| |
| INIT_DELAYED_WORK(&bat_priv->dat.work, batadv_dat_purge); |
| 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_dump_entry() - dump one entry of the DAT cache table to a |
| * netlink socket |
| * @msg: buffer for the message |
| * @portid: netlink port |
| * @cb: Control block containing additional options |
| * @dat_entry: entry to dump |
| * |
| * Return: 0 or error code. |
| */ |
| static int |
| batadv_dat_cache_dump_entry(struct sk_buff *msg, u32 portid, |
| struct netlink_callback *cb, |
| struct batadv_dat_entry *dat_entry) |
| { |
| int msecs; |
| void *hdr; |
| |
| hdr = genlmsg_put(msg, portid, cb->nlh->nlmsg_seq, |
| &batadv_netlink_family, NLM_F_MULTI, |
| BATADV_CMD_GET_DAT_CACHE); |
| if (!hdr) |
| return -ENOBUFS; |
| |
| genl_dump_check_consistent(cb, hdr); |
| |
| msecs = jiffies_to_msecs(jiffies - dat_entry->last_update); |
| |
| if (nla_put_in_addr(msg, BATADV_ATTR_DAT_CACHE_IP4ADDRESS, |
| dat_entry->ip) || |
| nla_put(msg, BATADV_ATTR_DAT_CACHE_HWADDRESS, ETH_ALEN, |
| dat_entry->mac_addr) || |
| nla_put_u16(msg, BATADV_ATTR_DAT_CACHE_VID, dat_entry->vid) || |
| nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS, msecs)) { |
| genlmsg_cancel(msg, hdr); |
| return -EMSGSIZE; |
| } |
| |
| genlmsg_end(msg, hdr); |
| return 0; |
| } |
| |
| /** |
| * batadv_dat_cache_dump_bucket() - dump one bucket of the DAT cache table to |
| * a netlink socket |
| * @msg: buffer for the message |
| * @portid: netlink port |
| * @cb: Control block containing additional options |
| * @hash: hash to dump |
| * @bucket: bucket index to dump |
| * @idx_skip: How many entries to skip |
| * |
| * Return: 0 or error code. |
| */ |
| static int |
| batadv_dat_cache_dump_bucket(struct sk_buff *msg, u32 portid, |
| struct netlink_callback *cb, |
| struct batadv_hashtable *hash, unsigned int bucket, |
| int *idx_skip) |
| { |
| struct batadv_dat_entry *dat_entry; |
| int idx = 0; |
| |
| spin_lock_bh(&hash->list_locks[bucket]); |
| cb->seq = atomic_read(&hash->generation) << 1 | 1; |
| |
| hlist_for_each_entry(dat_entry, &hash->table[bucket], hash_entry) { |
| if (idx < *idx_skip) |
| goto skip; |
| |
| if (batadv_dat_cache_dump_entry(msg, portid, cb, dat_entry)) { |
| spin_unlock_bh(&hash->list_locks[bucket]); |
| *idx_skip = idx; |
| |
| return -EMSGSIZE; |
| } |
| |
| skip: |
| idx++; |
| } |
| spin_unlock_bh(&hash->list_locks[bucket]); |
| |
| return 0; |
| } |
| |
| /** |
| * batadv_dat_cache_dump() - dump DAT cache table to a netlink socket |
| * @msg: buffer for the message |
| * @cb: callback structure containing arguments |
| * |
| * Return: message length. |
| */ |
| int batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb) |
| { |
| struct batadv_hard_iface *primary_if = NULL; |
| int portid = NETLINK_CB(cb->skb).portid; |
| struct net *net = sock_net(cb->skb->sk); |
| struct net_device *soft_iface; |
| struct batadv_hashtable *hash; |
| struct batadv_priv *bat_priv; |
| int bucket = cb->args[0]; |
| int idx = cb->args[1]; |
| int ifindex; |
| int ret = 0; |
| |
| ifindex = batadv_netlink_get_ifindex(cb->nlh, |
| BATADV_ATTR_MESH_IFINDEX); |
| if (!ifindex) |
| return -EINVAL; |
| |
| soft_iface = dev_get_by_index(net, ifindex); |
| if (!soft_iface || !batadv_softif_is_valid(soft_iface)) { |
| ret = -ENODEV; |
| goto out; |
| } |
| |
| bat_priv = netdev_priv(soft_iface); |
| hash = bat_priv->dat.hash; |
| |
| primary_if = batadv_primary_if_get_selected(bat_priv); |
| if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) { |
| ret = -ENOENT; |
| goto out; |
| } |
| |
| while (bucket < hash->size) { |
| if (batadv_dat_cache_dump_bucket(msg, portid, cb, hash, bucket, |
| &idx)) |
| break; |
| |
| bucket++; |
| idx = 0; |
| } |
| |
| cb->args[0] = bucket; |
| cb->args[1] = idx; |
| |
| ret = msg->len; |
| |
| out: |
| batadv_hardif_put(primary_if); |
| |
| dev_put(soft_iface); |
| |
| return ret; |
| } |
| |
| /** |
| * 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 |
| * |
| * Return: 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 |
| * |
| * Return: 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_arp_create_reply() - create an ARP Reply |
| * @bat_priv: the bat priv with all the soft interface information |
| * @ip_src: ARP sender IP |
| * @ip_dst: ARP target IP |
| * @hw_src: Ethernet source and ARP sender MAC |
| * @hw_dst: Ethernet destination and ARP target MAC |
| * @vid: VLAN identifier (optional, set to zero otherwise) |
| * |
| * Creates an ARP Reply from the given values, optionally encapsulated in a |
| * VLAN header. |
| * |
| * Return: An skb containing an ARP Reply. |
| */ |
| static struct sk_buff * |
| batadv_dat_arp_create_reply(struct batadv_priv *bat_priv, __be32 ip_src, |
| __be32 ip_dst, u8 *hw_src, u8 *hw_dst, |
| unsigned short vid) |
| { |
| struct sk_buff *skb; |
| |
| skb = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_dst, bat_priv->soft_iface, |
| ip_src, hw_dst, hw_src, hw_dst); |
| if (!skb) |
| return NULL; |
| |
| skb_reset_mac_header(skb); |
| |
| if (vid & BATADV_VLAN_HAS_TAG) |
| skb = vlan_insert_tag(skb, htons(ETH_P_8021Q), |
| vid & VLAN_VID_MASK); |
| |
| return skb; |
| } |
| |
| /** |
| * 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 |
| * |
| * Return: 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; |
| struct net_device *soft_iface = bat_priv->soft_iface; |
| 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, 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; |
| } |
| |
| /* If BLA is enabled, only send ARP replies if we have claimed |
| * the destination for the ARP request or if no one else of |
| * the backbone gws belonging to our backbone has claimed the |
| * destination. |
| */ |
| if (!batadv_bla_check_claim(bat_priv, |
| dat_entry->mac_addr, vid)) { |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, |
| "Device %pM claimed by another backbone gw. Don't send ARP reply!", |
| dat_entry->mac_addr); |
| ret = true; |
| goto out; |
| } |
| |
| skb_new = batadv_dat_arp_create_reply(bat_priv, ip_dst, ip_src, |
| dat_entry->mac_addr, |
| hw_src, vid); |
| if (!skb_new) |
| goto out; |
| |
| skb_new->protocol = eth_type_trans(skb_new, soft_iface); |
| |
| batadv_inc_counter(bat_priv, BATADV_CNT_RX); |
| batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES, |
| skb->len + ETH_HLEN + hdr_size); |
| |
| 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_forward_data(bat_priv, skb, ip_dst, vid, |
| BATADV_P_DAT_DHT_GET); |
| } |
| out: |
| batadv_dat_entry_put(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 |
| * |
| * Return: 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, 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 = batadv_dat_arp_create_reply(bat_priv, ip_dst, ip_src, |
| dat_entry->mac_addr, hw_src, vid); |
| if (!skb_new) |
| goto out; |
| |
| /* 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: |
| batadv_dat_entry_put(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, 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_forward_data(bat_priv, skb, ip_src, vid, |
| BATADV_P_DAT_DHT_PUT); |
| batadv_dat_forward_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 |
| * |
| * Return: 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) |
| { |
| struct batadv_dat_entry *dat_entry = NULL; |
| 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, 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); |
| |
| /* If ip_dst is already in cache and has the right mac address, |
| * drop this frame if this ARP reply is destined for us because it's |
| * most probably an ARP reply generated by another node of the DHT. |
| * We have most probably received already a reply earlier. Delivering |
| * this frame would lead to doubled receive of an ARP reply. |
| */ |
| dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_src, vid); |
| if (dat_entry && batadv_compare_eth(hw_src, dat_entry->mac_addr)) { |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, "Doubled ARP reply removed: ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]; dat_entry: %pM-%pI4\n", |
| hw_src, &ip_src, hw_dst, &ip_dst, |
| dat_entry->mac_addr, &dat_entry->ip); |
| dropped = true; |
| } |
| |
| /* 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 (dropped) |
| goto out; |
| |
| /* If BLA is enabled, only forward ARP replies if we have claimed the |
| * source of the ARP reply or if no one else of the same backbone has |
| * already claimed that client. This prevents that different gateways |
| * to the same backbone all forward the ARP reply leading to multiple |
| * replies in the backbone. |
| */ |
| if (!batadv_bla_check_claim(bat_priv, hw_src, vid)) { |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, |
| "Device %pM claimed by another backbone gw. Drop ARP reply.\n", |
| hw_src); |
| dropped = true; |
| goto out; |
| } |
| |
| /* 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); |
| batadv_dat_entry_put(dat_entry); |
| /* if dropped == false -> deliver to the interface */ |
| return dropped; |
| } |
| |
| /** |
| * batadv_dat_check_dhcp_ipudp() - check skb for IP+UDP headers valid for DHCP |
| * @skb: the packet to check |
| * @ip_src: a buffer to store the IPv4 source address in |
| * |
| * Checks whether the given skb has an IP and UDP header valid for a DHCP |
| * message from a DHCP server. And if so, stores the IPv4 source address in |
| * the provided buffer. |
| * |
| * Return: True if valid, false otherwise. |
| */ |
| static bool |
| batadv_dat_check_dhcp_ipudp(struct sk_buff *skb, __be32 *ip_src) |
| { |
| unsigned int offset = skb_network_offset(skb); |
| struct udphdr *udphdr, _udphdr; |
| struct iphdr *iphdr, _iphdr; |
| |
| iphdr = skb_header_pointer(skb, offset, sizeof(_iphdr), &_iphdr); |
| if (!iphdr || iphdr->version != 4 || iphdr->ihl * 4 < sizeof(_iphdr)) |
| return false; |
| |
| if (iphdr->protocol != IPPROTO_UDP) |
| return false; |
| |
| offset += iphdr->ihl * 4; |
| skb_set_transport_header(skb, offset); |
| |
| udphdr = skb_header_pointer(skb, offset, sizeof(_udphdr), &_udphdr); |
| if (!udphdr || udphdr->source != htons(67)) |
| return false; |
| |
| *ip_src = get_unaligned(&iphdr->saddr); |
| |
| return true; |
| } |
| |
| /** |
| * batadv_dat_check_dhcp() - examine packet for valid DHCP message |
| * @skb: the packet to check |
| * @proto: ethernet protocol hint (behind a potential vlan) |
| * @ip_src: a buffer to store the IPv4 source address in |
| * |
| * Checks whether the given skb is a valid DHCP packet. And if so, stores the |
| * IPv4 source address in the provided buffer. |
| * |
| * Caller needs to ensure that the skb network header is set correctly. |
| * |
| * Return: If skb is a valid DHCP packet, then returns its op code |
| * (e.g. BOOTREPLY vs. BOOTREQUEST). Otherwise returns -EINVAL. |
| */ |
| static int |
| batadv_dat_check_dhcp(struct sk_buff *skb, __be16 proto, __be32 *ip_src) |
| { |
| __be32 *magic, _magic; |
| unsigned int offset; |
| struct { |
| __u8 op; |
| __u8 htype; |
| __u8 hlen; |
| __u8 hops; |
| } *dhcp_h, _dhcp_h; |
| |
| if (proto != htons(ETH_P_IP)) |
| return -EINVAL; |
| |
| if (!batadv_dat_check_dhcp_ipudp(skb, ip_src)) |
| return -EINVAL; |
| |
| offset = skb_transport_offset(skb) + sizeof(struct udphdr); |
| if (skb->len < offset + sizeof(struct batadv_dhcp_packet)) |
| return -EINVAL; |
| |
| dhcp_h = skb_header_pointer(skb, offset, sizeof(_dhcp_h), &_dhcp_h); |
| if (!dhcp_h || dhcp_h->htype != BATADV_HTYPE_ETHERNET || |
| dhcp_h->hlen != ETH_ALEN) |
| return -EINVAL; |
| |
| offset += offsetof(struct batadv_dhcp_packet, magic); |
| |
| magic = skb_header_pointer(skb, offset, sizeof(_magic), &_magic); |
| if (!magic || get_unaligned(magic) != htonl(BATADV_DHCP_MAGIC)) |
| return -EINVAL; |
| |
| return dhcp_h->op; |
| } |
| |
| /** |
| * batadv_dat_get_dhcp_message_type() - get message type of a DHCP packet |
| * @skb: the DHCP packet to parse |
| * |
| * Iterates over the DHCP options of the given DHCP packet to find a |
| * DHCP Message Type option and parse it. |
| * |
| * Caller needs to ensure that the given skb is a valid DHCP packet and |
| * that the skb transport header is set correctly. |
| * |
| * Return: The found DHCP message type value, if found. -EINVAL otherwise. |
| */ |
| static int batadv_dat_get_dhcp_message_type(struct sk_buff *skb) |
| { |
| unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr); |
| u8 *type, _type; |
| struct { |
| u8 type; |
| u8 len; |
| } *tl, _tl; |
| |
| offset += sizeof(struct batadv_dhcp_packet); |
| |
| while ((tl = skb_header_pointer(skb, offset, sizeof(_tl), &_tl))) { |
| if (tl->type == BATADV_DHCP_OPT_MSG_TYPE) |
| break; |
| |
| if (tl->type == BATADV_DHCP_OPT_END) |
| break; |
| |
| if (tl->type == BATADV_DHCP_OPT_PAD) |
| offset++; |
| else |
| offset += tl->len + sizeof(_tl); |
| } |
| |
| /* Option Overload Code not supported */ |
| if (!tl || tl->type != BATADV_DHCP_OPT_MSG_TYPE || |
| tl->len != sizeof(_type)) |
| return -EINVAL; |
| |
| offset += sizeof(_tl); |
| |
| type = skb_header_pointer(skb, offset, sizeof(_type), &_type); |
| if (!type) |
| return -EINVAL; |
| |
| return *type; |
| } |
| |
| /** |
| * batadv_dat_dhcp_get_yiaddr() - get yiaddr from a DHCP packet |
| * @skb: the DHCP packet to parse |
| * @buf: a buffer to store the yiaddr in |
| * |
| * Caller needs to ensure that the given skb is a valid DHCP packet and |
| * that the skb transport header is set correctly. |
| * |
| * Return: True on success, false otherwise. |
| */ |
| static bool batadv_dat_dhcp_get_yiaddr(struct sk_buff *skb, __be32 *buf) |
| { |
| unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr); |
| __be32 *yiaddr; |
| |
| offset += offsetof(struct batadv_dhcp_packet, yiaddr); |
| yiaddr = skb_header_pointer(skb, offset, BATADV_DHCP_YIADDR_LEN, buf); |
| |
| if (!yiaddr) |
| return false; |
| |
| if (yiaddr != buf) |
| *buf = get_unaligned(yiaddr); |
| |
| return true; |
| } |
| |
| /** |
| * batadv_dat_get_dhcp_chaddr() - get chaddr from a DHCP packet |
| * @skb: the DHCP packet to parse |
| * @buf: a buffer to store the chaddr in |
| * |
| * Caller needs to ensure that the given skb is a valid DHCP packet and |
| * that the skb transport header is set correctly. |
| * |
| * Return: True on success, false otherwise |
| */ |
| static bool batadv_dat_get_dhcp_chaddr(struct sk_buff *skb, u8 *buf) |
| { |
| unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr); |
| u8 *chaddr; |
| |
| offset += offsetof(struct batadv_dhcp_packet, chaddr); |
| chaddr = skb_header_pointer(skb, offset, BATADV_DHCP_CHADDR_LEN, buf); |
| |
| if (!chaddr) |
| return false; |
| |
| if (chaddr != buf) |
| memcpy(buf, chaddr, BATADV_DHCP_CHADDR_LEN); |
| |
| return true; |
| } |
| |
| /** |
| * batadv_dat_put_dhcp() - puts addresses from a DHCP packet into the DHT and |
| * DAT cache |
| * @bat_priv: the bat priv with all the soft interface information |
| * @chaddr: the DHCP client MAC address |
| * @yiaddr: the DHCP client IP address |
| * @hw_dst: the DHCP server MAC address |
| * @ip_dst: the DHCP server IP address |
| * @vid: VLAN identifier |
| * |
| * Adds given MAC/IP pairs to the local DAT cache and propagates them further |
| * into the DHT. |
| * |
| * For the DHT propagation, client MAC + IP will appear as the ARP Reply |
| * transmitter (and hw_dst/ip_dst as the target). |
| */ |
| static void batadv_dat_put_dhcp(struct batadv_priv *bat_priv, u8 *chaddr, |
| __be32 yiaddr, u8 *hw_dst, __be32 ip_dst, |
| unsigned short vid) |
| { |
| struct sk_buff *skb; |
| |
| skb = batadv_dat_arp_create_reply(bat_priv, yiaddr, ip_dst, chaddr, |
| hw_dst, vid); |
| if (!skb) |
| return; |
| |
| skb_set_network_header(skb, ETH_HLEN); |
| |
| batadv_dat_entry_add(bat_priv, yiaddr, chaddr, vid); |
| batadv_dat_entry_add(bat_priv, ip_dst, hw_dst, vid); |
| |
| batadv_dat_forward_data(bat_priv, skb, yiaddr, vid, |
| BATADV_P_DAT_DHT_PUT); |
| batadv_dat_forward_data(bat_priv, skb, ip_dst, vid, |
| BATADV_P_DAT_DHT_PUT); |
| |
| consume_skb(skb); |
| |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, |
| "Snooped from outgoing DHCPACK (server address): %pI4, %pM (vid: %i)\n", |
| &ip_dst, hw_dst, batadv_print_vid(vid)); |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, |
| "Snooped from outgoing DHCPACK (client address): %pI4, %pM (vid: %i)\n", |
| &yiaddr, chaddr, batadv_print_vid(vid)); |
| } |
| |
| /** |
| * batadv_dat_check_dhcp_ack() - examine packet for valid DHCP message |
| * @skb: the packet to check |
| * @proto: ethernet protocol hint (behind a potential vlan) |
| * @ip_src: a buffer to store the IPv4 source address in |
| * @chaddr: a buffer to store the DHCP Client Hardware Address in |
| * @yiaddr: a buffer to store the DHCP Your IP Address in |
| * |
| * Checks whether the given skb is a valid DHCPACK. And if so, stores the |
| * IPv4 server source address (ip_src), client MAC address (chaddr) and client |
| * IPv4 address (yiaddr) in the provided buffers. |
| * |
| * Caller needs to ensure that the skb network header is set correctly. |
| * |
| * Return: True if the skb is a valid DHCPACK. False otherwise. |
| */ |
| static bool |
| batadv_dat_check_dhcp_ack(struct sk_buff *skb, __be16 proto, __be32 *ip_src, |
| u8 *chaddr, __be32 *yiaddr) |
| { |
| int type; |
| |
| type = batadv_dat_check_dhcp(skb, proto, ip_src); |
| if (type != BATADV_BOOTREPLY) |
| return false; |
| |
| type = batadv_dat_get_dhcp_message_type(skb); |
| if (type != BATADV_DHCPACK) |
| return false; |
| |
| if (!batadv_dat_dhcp_get_yiaddr(skb, yiaddr)) |
| return false; |
| |
| if (!batadv_dat_get_dhcp_chaddr(skb, chaddr)) |
| return false; |
| |
| return true; |
| } |
| |
| /** |
| * batadv_dat_snoop_outgoing_dhcp_ack() - snoop DHCPACK and fill DAT with it |
| * @bat_priv: the bat priv with all the soft interface information |
| * @skb: the packet to snoop |
| * @proto: ethernet protocol hint (behind a potential vlan) |
| * @vid: VLAN identifier |
| * |
| * This function first checks whether the given skb is a valid DHCPACK. If |
| * so then its source MAC and IP as well as its DHCP Client Hardware Address |
| * field and DHCP Your IP Address field are added to the local DAT cache and |
| * propagated into the DHT. |
| * |
| * Caller needs to ensure that the skb mac and network headers are set |
| * correctly. |
| */ |
| void batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv, |
| struct sk_buff *skb, |
| __be16 proto, |
| unsigned short vid) |
| { |
| u8 chaddr[BATADV_DHCP_CHADDR_LEN]; |
| __be32 ip_src, yiaddr; |
| |
| if (!atomic_read(&bat_priv->distributed_arp_table)) |
| return; |
| |
| if (!batadv_dat_check_dhcp_ack(skb, proto, &ip_src, chaddr, &yiaddr)) |
| return; |
| |
| batadv_dat_put_dhcp(bat_priv, chaddr, yiaddr, eth_hdr(skb)->h_source, |
| ip_src, vid); |
| } |
| |
| /** |
| * batadv_dat_snoop_incoming_dhcp_ack() - snoop DHCPACK and fill DAT cache |
| * @bat_priv: the bat priv with all the soft interface information |
| * @skb: the packet to snoop |
| * @hdr_size: header size, up to the tail of the batman-adv header |
| * |
| * This function first checks whether the given skb is a valid DHCPACK. If |
| * so then its source MAC and IP as well as its DHCP Client Hardware Address |
| * field and DHCP Your IP Address field are added to the local DAT cache. |
| */ |
| void batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv, |
| struct sk_buff *skb, int hdr_size) |
| { |
| u8 chaddr[BATADV_DHCP_CHADDR_LEN]; |
| struct ethhdr *ethhdr; |
| __be32 ip_src, yiaddr; |
| unsigned short vid; |
| __be16 proto; |
| u8 *hw_src; |
| |
| if (!atomic_read(&bat_priv->distributed_arp_table)) |
| return; |
| |
| if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN))) |
| return; |
| |
| ethhdr = (struct ethhdr *)(skb->data + hdr_size); |
| skb_set_network_header(skb, hdr_size + ETH_HLEN); |
| proto = ethhdr->h_proto; |
| |
| if (!batadv_dat_check_dhcp_ack(skb, proto, &ip_src, chaddr, &yiaddr)) |
| return; |
| |
| hw_src = ethhdr->h_source; |
| vid = batadv_dat_get_vid(skb, &hdr_size); |
| |
| batadv_dat_entry_add(bat_priv, yiaddr, chaddr, vid); |
| batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); |
| |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, |
| "Snooped from incoming DHCPACK (server address): %pI4, %pM (vid: %i)\n", |
| &ip_src, hw_src, batadv_print_vid(vid)); |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, |
| "Snooped from incoming DHCPACK (client address): %pI4, %pM (vid: %i)\n", |
| &yiaddr, chaddr, batadv_print_vid(vid)); |
| } |
| |
| /** |
| * 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 |
| * |
| * Return: 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 (batadv_forw_packet_is_rebroadcast(forw_packet)) |
| 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: |
| batadv_dat_entry_put(dat_entry); |
| return ret; |
| } |