diff options
Diffstat (limited to 'net/batman-adv/distributed-arp-table.c')
| -rw-r--r-- | net/batman-adv/distributed-arp-table.c | 1831 |
1 files changed, 1831 insertions, 0 deletions
diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c new file mode 100644 index 000000000..28a939d56 --- /dev/null +++ b/net/batman-adv/distributed-arp-table.c @@ -0,0 +1,1831 @@ +// 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, 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; +} |