/
routing.c
1303 lines (1047 loc) · 35.9 KB
/
routing.c
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/* Copyright (C) 2007-2013 B.A.T.M.A.N. contributors:
*
* Marek Lindner, Simon Wunderlich
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*/
#include "main.h"
#include "routing.h"
#include "send.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "icmp_socket.h"
#include "translation-table.h"
#include "originator.h"
#include "unicast.h"
#include "bridge_loop_avoidance.h"
#include "distributed-arp-table.h"
#include "network-coding.h"
static int batadv_route_unicast_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if);
static void _batadv_update_route(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
struct batadv_neigh_node *neigh_node)
{
struct batadv_neigh_node *curr_router;
curr_router = batadv_orig_node_get_router(orig_node);
/* route deleted */
if ((curr_router) && (!neigh_node)) {
batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
"Deleting route towards: %pM\n", orig_node->orig);
batadv_tt_global_del_orig(bat_priv, orig_node,
"Deleted route towards originator");
/* route added */
} else if ((!curr_router) && (neigh_node)) {
batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
"Adding route towards: %pM (via %pM)\n",
orig_node->orig, neigh_node->addr);
/* route changed */
} else if (neigh_node && curr_router) {
batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
"Changing route towards: %pM (now via %pM - was via %pM)\n",
orig_node->orig, neigh_node->addr,
curr_router->addr);
}
if (curr_router)
batadv_neigh_node_free_ref(curr_router);
/* increase refcount of new best neighbor */
if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
neigh_node = NULL;
spin_lock_bh(&orig_node->neigh_list_lock);
rcu_assign_pointer(orig_node->router, neigh_node);
spin_unlock_bh(&orig_node->neigh_list_lock);
/* decrease refcount of previous best neighbor */
if (curr_router)
batadv_neigh_node_free_ref(curr_router);
}
void batadv_update_route(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
struct batadv_neigh_node *neigh_node)
{
struct batadv_neigh_node *router = NULL;
if (!orig_node)
goto out;
router = batadv_orig_node_get_router(orig_node);
if (router != neigh_node)
_batadv_update_route(bat_priv, orig_node, neigh_node);
out:
if (router)
batadv_neigh_node_free_ref(router);
}
/* caller must hold the neigh_list_lock */
void batadv_bonding_candidate_del(struct batadv_orig_node *orig_node,
struct batadv_neigh_node *neigh_node)
{
/* this neighbor is not part of our candidate list */
if (list_empty(&neigh_node->bonding_list))
goto out;
list_del_rcu(&neigh_node->bonding_list);
INIT_LIST_HEAD(&neigh_node->bonding_list);
batadv_neigh_node_free_ref(neigh_node);
atomic_dec(&orig_node->bond_candidates);
out:
return;
}
void batadv_bonding_candidate_add(struct batadv_orig_node *orig_node,
struct batadv_neigh_node *neigh_node)
{
struct batadv_neigh_node *tmp_neigh_node, *router = NULL;
uint8_t interference_candidate = 0;
spin_lock_bh(&orig_node->neigh_list_lock);
/* only consider if it has the same primary address ... */
if (!batadv_compare_eth(orig_node->orig,
neigh_node->orig_node->primary_addr))
goto candidate_del;
router = batadv_orig_node_get_router(orig_node);
if (!router)
goto candidate_del;
/* ... and is good enough to be considered */
if (neigh_node->tq_avg < router->tq_avg - BATADV_BONDING_TQ_THRESHOLD)
goto candidate_del;
/* check if we have another candidate with the same mac address or
* interface. If we do, we won't select this candidate because of
* possible interference.
*/
hlist_for_each_entry_rcu(tmp_neigh_node,
&orig_node->neigh_list, list) {
if (tmp_neigh_node == neigh_node)
continue;
/* we only care if the other candidate is even
* considered as candidate.
*/
if (list_empty(&tmp_neigh_node->bonding_list))
continue;
if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
(batadv_compare_eth(neigh_node->addr,
tmp_neigh_node->addr))) {
interference_candidate = 1;
break;
}
}
/* don't care further if it is an interference candidate */
if (interference_candidate)
goto candidate_del;
/* this neighbor already is part of our candidate list */
if (!list_empty(&neigh_node->bonding_list))
goto out;
if (!atomic_inc_not_zero(&neigh_node->refcount))
goto out;
list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
atomic_inc(&orig_node->bond_candidates);
goto out;
candidate_del:
batadv_bonding_candidate_del(orig_node, neigh_node);
out:
spin_unlock_bh(&orig_node->neigh_list_lock);
if (router)
batadv_neigh_node_free_ref(router);
}
/* copy primary address for bonding */
void
batadv_bonding_save_primary(const struct batadv_orig_node *orig_node,
struct batadv_orig_node *orig_neigh_node,
const struct batadv_ogm_packet *batman_ogm_packet)
{
if (!(batman_ogm_packet->flags & BATADV_PRIMARIES_FIRST_HOP))
return;
memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
}
/* checks whether the host restarted and is in the protection time.
* returns:
* 0 if the packet is to be accepted
* 1 if the packet is to be ignored.
*/
int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
unsigned long *last_reset)
{
if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
if (!batadv_has_timed_out(*last_reset,
BATADV_RESET_PROTECTION_MS))
return 1;
*last_reset = jiffies;
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"old packet received, start protection\n");
}
return 0;
}
bool batadv_check_management_packet(struct sk_buff *skb,
struct batadv_hard_iface *hard_iface,
int header_len)
{
struct ethhdr *ethhdr;
/* drop packet if it has not necessary minimum size */
if (unlikely(!pskb_may_pull(skb, header_len)))
return false;
ethhdr = eth_hdr(skb);
/* packet with broadcast indication but unicast recipient */
if (!is_broadcast_ether_addr(ethhdr->h_dest))
return false;
/* packet with broadcast sender address */
if (is_broadcast_ether_addr(ethhdr->h_source))
return false;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, 0) < 0)
return false;
/* keep skb linear */
if (skb_linearize(skb) < 0)
return false;
return true;
}
static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
struct sk_buff *skb, size_t icmp_len)
{
struct batadv_hard_iface *primary_if = NULL;
struct batadv_orig_node *orig_node = NULL;
struct batadv_icmp_packet_rr *icmp_packet;
int ret = NET_RX_DROP;
icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
/* add data to device queue */
if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
batadv_socket_receive_packet(icmp_packet, icmp_len);
goto out;
}
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto out;
/* answer echo request (ping) */
/* get routing information */
orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
if (!orig_node)
goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto out;
icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
icmp_packet->msg_type = BATADV_ECHO_REPLY;
icmp_packet->header.ttl = BATADV_TTL;
if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
ret = NET_RX_SUCCESS;
out:
if (primary_if)
batadv_hardif_free_ref(primary_if);
if (orig_node)
batadv_orig_node_free_ref(orig_node);
return ret;
}
static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
struct sk_buff *skb)
{
struct batadv_hard_iface *primary_if = NULL;
struct batadv_orig_node *orig_node = NULL;
struct batadv_icmp_packet *icmp_packet;
int ret = NET_RX_DROP;
icmp_packet = (struct batadv_icmp_packet *)skb->data;
/* send TTL exceeded if packet is an echo request (traceroute) */
if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
icmp_packet->orig, icmp_packet->dst);
goto out;
}
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto out;
/* get routing information */
orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
if (!orig_node)
goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto out;
icmp_packet = (struct batadv_icmp_packet *)skb->data;
memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
icmp_packet->header.ttl = BATADV_TTL;
if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
ret = NET_RX_SUCCESS;
out:
if (primary_if)
batadv_hardif_free_ref(primary_if);
if (orig_node)
batadv_orig_node_free_ref(orig_node);
return ret;
}
int batadv_recv_icmp_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if)
{
struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
struct batadv_icmp_packet_rr *icmp_packet;
struct ethhdr *ethhdr;
struct batadv_orig_node *orig_node = NULL;
int hdr_size = sizeof(struct batadv_icmp_packet);
int ret = NET_RX_DROP;
/* we truncate all incoming icmp packets if they don't match our size */
if (skb->len >= sizeof(struct batadv_icmp_packet_rr))
hdr_size = sizeof(struct batadv_icmp_packet_rr);
/* drop packet if it has not necessary minimum size */
if (unlikely(!pskb_may_pull(skb, hdr_size)))
goto out;
ethhdr = eth_hdr(skb);
/* packet with unicast indication but broadcast recipient */
if (is_broadcast_ether_addr(ethhdr->h_dest))
goto out;
/* packet with broadcast sender address */
if (is_broadcast_ether_addr(ethhdr->h_source))
goto out;
/* not for me */
if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
goto out;
icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
/* add record route information if not full */
if ((hdr_size == sizeof(struct batadv_icmp_packet_rr)) &&
(icmp_packet->rr_cur < BATADV_RR_LEN)) {
memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
ethhdr->h_dest, ETH_ALEN);
icmp_packet->rr_cur++;
}
/* packet for me */
if (batadv_is_my_mac(bat_priv, icmp_packet->dst))
return batadv_recv_my_icmp_packet(bat_priv, skb, hdr_size);
/* TTL exceeded */
if (icmp_packet->header.ttl < 2)
return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
/* get routing information */
orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->dst);
if (!orig_node)
goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto out;
icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
/* decrement ttl */
icmp_packet->header.ttl--;
/* route it */
if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
ret = NET_RX_SUCCESS;
out:
if (orig_node)
batadv_orig_node_free_ref(orig_node);
return ret;
}
/* In the bonding case, send the packets in a round
* robin fashion over the remaining interfaces.
*
* This method rotates the bonding list and increases the
* returned router's refcount.
*/
static struct batadv_neigh_node *
batadv_find_bond_router(struct batadv_orig_node *primary_orig,
const struct batadv_hard_iface *recv_if)
{
struct batadv_neigh_node *tmp_neigh_node;
struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
rcu_read_lock();
list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
bonding_list) {
if (!first_candidate)
first_candidate = tmp_neigh_node;
/* recv_if == NULL on the first node. */
if (tmp_neigh_node->if_incoming == recv_if)
continue;
if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
continue;
router = tmp_neigh_node;
break;
}
/* use the first candidate if nothing was found. */
if (!router && first_candidate &&
atomic_inc_not_zero(&first_candidate->refcount))
router = first_candidate;
if (!router)
goto out;
/* selected should point to the next element
* after the current router
*/
spin_lock_bh(&primary_orig->neigh_list_lock);
/* this is a list_move(), which unfortunately
* does not exist as rcu version
*/
list_del_rcu(&primary_orig->bond_list);
list_add_rcu(&primary_orig->bond_list,
&router->bonding_list);
spin_unlock_bh(&primary_orig->neigh_list_lock);
out:
rcu_read_unlock();
return router;
}
/* Interface Alternating: Use the best of the
* remaining candidates which are not using
* this interface.
*
* Increases the returned router's refcount
*/
static struct batadv_neigh_node *
batadv_find_ifalter_router(struct batadv_orig_node *primary_orig,
const struct batadv_hard_iface *recv_if)
{
struct batadv_neigh_node *tmp_neigh_node;
struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
rcu_read_lock();
list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
bonding_list) {
if (!first_candidate)
first_candidate = tmp_neigh_node;
/* recv_if == NULL on the first node. */
if (tmp_neigh_node->if_incoming == recv_if)
continue;
if (router && tmp_neigh_node->tq_avg <= router->tq_avg)
continue;
if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
continue;
/* decrement refcount of previously selected router */
if (router)
batadv_neigh_node_free_ref(router);
/* we found a better router (or at least one valid router) */
router = tmp_neigh_node;
}
/* use the first candidate if nothing was found. */
if (!router && first_candidate &&
atomic_inc_not_zero(&first_candidate->refcount))
router = first_candidate;
rcu_read_unlock();
return router;
}
/**
* batadv_check_unicast_packet - Check for malformed unicast packets
* @bat_priv: the bat priv with all the soft interface information
* @skb: packet to check
* @hdr_size: size of header to pull
*
* Check for short header and bad addresses in given packet. Returns negative
* value when check fails and 0 otherwise. The negative value depends on the
* reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
* and -EREMOTE for non-local (other host) destination.
*/
static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size)
{
struct ethhdr *ethhdr;
/* drop packet if it has not necessary minimum size */
if (unlikely(!pskb_may_pull(skb, hdr_size)))
return -ENODATA;
ethhdr = eth_hdr(skb);
/* packet with unicast indication but broadcast recipient */
if (is_broadcast_ether_addr(ethhdr->h_dest))
return -EBADR;
/* packet with broadcast sender address */
if (is_broadcast_ether_addr(ethhdr->h_source))
return -EBADR;
/* not for me */
if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
return -EREMOTE;
return 0;
}
int batadv_recv_tt_query(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
{
struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
struct batadv_tt_query_packet *tt_query;
uint16_t tt_size;
int hdr_size = sizeof(*tt_query);
char tt_flag;
size_t packet_size;
if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
return NET_RX_DROP;
/* I could need to modify it */
if (skb_cow(skb, sizeof(struct batadv_tt_query_packet)) < 0)
goto out;
tt_query = (struct batadv_tt_query_packet *)skb->data;
switch (tt_query->flags & BATADV_TT_QUERY_TYPE_MASK) {
case BATADV_TT_REQUEST:
batadv_inc_counter(bat_priv, BATADV_CNT_TT_REQUEST_RX);
/* If we cannot provide an answer the tt_request is
* forwarded
*/
if (!batadv_send_tt_response(bat_priv, tt_query)) {
if (tt_query->flags & BATADV_TT_FULL_TABLE)
tt_flag = 'F';
else
tt_flag = '.';
batadv_dbg(BATADV_DBG_TT, bat_priv,
"Routing TT_REQUEST to %pM [%c]\n",
tt_query->dst,
tt_flag);
return batadv_route_unicast_packet(skb, recv_if);
}
break;
case BATADV_TT_RESPONSE:
batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_RX);
if (batadv_is_my_mac(bat_priv, tt_query->dst)) {
/* packet needs to be linearized to access the TT
* changes
*/
if (skb_linearize(skb) < 0)
goto out;
/* skb_linearize() possibly changed skb->data */
tt_query = (struct batadv_tt_query_packet *)skb->data;
tt_size = batadv_tt_len(ntohs(tt_query->tt_data));
/* Ensure we have all the claimed data */
packet_size = sizeof(struct batadv_tt_query_packet);
packet_size += tt_size;
if (unlikely(skb_headlen(skb) < packet_size))
goto out;
batadv_handle_tt_response(bat_priv, tt_query);
} else {
if (tt_query->flags & BATADV_TT_FULL_TABLE)
tt_flag = 'F';
else
tt_flag = '.';
batadv_dbg(BATADV_DBG_TT, bat_priv,
"Routing TT_RESPONSE to %pM [%c]\n",
tt_query->dst,
tt_flag);
return batadv_route_unicast_packet(skb, recv_if);
}
break;
}
out:
/* returning NET_RX_DROP will make the caller function kfree the skb */
return NET_RX_DROP;
}
int batadv_recv_roam_adv(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
{
struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
struct batadv_roam_adv_packet *roam_adv_packet;
struct batadv_orig_node *orig_node;
if (batadv_check_unicast_packet(bat_priv, skb,
sizeof(*roam_adv_packet)) < 0)
goto out;
batadv_inc_counter(bat_priv, BATADV_CNT_TT_ROAM_ADV_RX);
roam_adv_packet = (struct batadv_roam_adv_packet *)skb->data;
if (!batadv_is_my_mac(bat_priv, roam_adv_packet->dst))
return batadv_route_unicast_packet(skb, recv_if);
/* check if it is a backbone gateway. we don't accept
* roaming advertisement from it, as it has the same
* entries as we have.
*/
if (batadv_bla_is_backbone_gw_orig(bat_priv, roam_adv_packet->src))
goto out;
orig_node = batadv_orig_hash_find(bat_priv, roam_adv_packet->src);
if (!orig_node)
goto out;
batadv_dbg(BATADV_DBG_TT, bat_priv,
"Received ROAMING_ADV from %pM (client %pM)\n",
roam_adv_packet->src, roam_adv_packet->client);
batadv_tt_global_add(bat_priv, orig_node, roam_adv_packet->client,
BATADV_TT_V14_CLIENT_ROAM,
atomic_read(&orig_node->last_ttvn) + 1);
batadv_orig_node_free_ref(orig_node);
out:
/* returning NET_RX_DROP will make the caller function kfree the skb */
return NET_RX_DROP;
}
/* find a suitable router for this originator, and use
* bonding if possible. increases the found neighbors
* refcount.
*/
struct batadv_neigh_node *
batadv_find_router(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
const struct batadv_hard_iface *recv_if)
{
struct batadv_orig_node *primary_orig_node;
struct batadv_orig_node *router_orig;
struct batadv_neigh_node *router;
static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
int bonding_enabled;
uint8_t *primary_addr;
if (!orig_node)
return NULL;
router = batadv_orig_node_get_router(orig_node);
if (!router)
goto err;
/* without bonding, the first node should
* always choose the default router.
*/
bonding_enabled = atomic_read(&bat_priv->bonding);
rcu_read_lock();
/* select default router to output */
router_orig = router->orig_node;
if (!router_orig)
goto err_unlock;
if ((!recv_if) && (!bonding_enabled))
goto return_router;
primary_addr = router_orig->primary_addr;
/* if we have something in the primary_addr, we can search
* for a potential bonding candidate.
*/
if (batadv_compare_eth(primary_addr, zero_mac))
goto return_router;
/* find the orig_node which has the primary interface. might
* even be the same as our router_orig in many cases
*/
if (batadv_compare_eth(primary_addr, router_orig->orig)) {
primary_orig_node = router_orig;
} else {
primary_orig_node = batadv_orig_hash_find(bat_priv,
primary_addr);
if (!primary_orig_node)
goto return_router;
batadv_orig_node_free_ref(primary_orig_node);
}
/* with less than 2 candidates, we can't do any
* bonding and prefer the original router.
*/
if (atomic_read(&primary_orig_node->bond_candidates) < 2)
goto return_router;
/* all nodes between should choose a candidate which
* is is not on the interface where the packet came
* in.
*/
batadv_neigh_node_free_ref(router);
if (bonding_enabled)
router = batadv_find_bond_router(primary_orig_node, recv_if);
else
router = batadv_find_ifalter_router(primary_orig_node, recv_if);
return_router:
if (router && router->if_incoming->if_status != BATADV_IF_ACTIVE)
goto err_unlock;
rcu_read_unlock();
return router;
err_unlock:
rcu_read_unlock();
err:
if (router)
batadv_neigh_node_free_ref(router);
return NULL;
}
static int batadv_route_unicast_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if)
{
struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
struct batadv_orig_node *orig_node = NULL;
struct batadv_neigh_node *neigh_node = NULL;
struct batadv_unicast_packet *unicast_packet;
struct ethhdr *ethhdr = eth_hdr(skb);
int res, ret = NET_RX_DROP;
struct sk_buff *new_skb;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
/* TTL exceeded */
if (unicast_packet->header.ttl < 2) {
pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
ethhdr->h_source, unicast_packet->dest);
goto out;
}
/* get routing information */
orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
if (!orig_node)
goto out;
/* find_router() increases neigh_nodes refcount if found. */
neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
if (!neigh_node)
goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto out;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
if (unicast_packet->header.packet_type == BATADV_UNICAST &&
atomic_read(&bat_priv->fragmentation) &&
skb->len > neigh_node->if_incoming->net_dev->mtu) {
ret = batadv_frag_send_skb(skb, bat_priv,
neigh_node->if_incoming,
neigh_node->addr);
goto out;
}
if (unicast_packet->header.packet_type == BATADV_UNICAST_FRAG &&
batadv_frag_can_reassemble(skb,
neigh_node->if_incoming->net_dev->mtu)) {
ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
if (ret == NET_RX_DROP)
goto out;
/* packet was buffered for late merge */
if (!new_skb) {
ret = NET_RX_SUCCESS;
goto out;
}
skb = new_skb;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
}
/* decrement ttl */
unicast_packet->header.ttl--;
res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
/* translate transmit result into receive result */
if (res == NET_XMIT_SUCCESS) {
/* skb was transmitted and consumed */
batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
skb->len + ETH_HLEN);
ret = NET_RX_SUCCESS;
} else if (res == -EINPROGRESS) {
/* skb was buffered and consumed */
ret = NET_RX_SUCCESS;
}
out:
if (neigh_node)
batadv_neigh_node_free_ref(neigh_node);
if (orig_node)
batadv_orig_node_free_ref(orig_node);
return ret;
}
/**
* batadv_reroute_unicast_packet - update the unicast header for re-routing
* @bat_priv: the bat priv with all the soft interface information
* @unicast_packet: the unicast header to be updated
* @dst_addr: the payload destination
*
* Search the translation table for dst_addr and update the unicast header with
* the new corresponding information (originator address where the destination
* client currently is and its known TTVN)
*
* Returns true if the packet header has been updated, false otherwise
*/
static bool
batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
struct batadv_unicast_packet *unicast_packet,
uint8_t *dst_addr)
{
struct batadv_orig_node *orig_node = NULL;
struct batadv_hard_iface *primary_if = NULL;
bool ret = false;
uint8_t *orig_addr, orig_ttvn;
if (batadv_is_my_client(bat_priv, dst_addr)) {
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto out;
orig_addr = primary_if->net_dev->dev_addr;
orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
} else {
orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr);
if (!orig_node)
goto out;
if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
goto out;
orig_addr = orig_node->orig;
orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
}
/* update the packet header */
memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
unicast_packet->ttvn = orig_ttvn;
ret = true;
out:
if (primary_if)
batadv_hardif_free_ref(primary_if);
if (orig_node)
batadv_orig_node_free_ref(orig_node);
return ret;
}
static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_len) {
uint8_t curr_ttvn, old_ttvn;
struct batadv_orig_node *orig_node;
struct ethhdr *ethhdr;
struct batadv_hard_iface *primary_if;
struct batadv_unicast_packet *unicast_packet;
int is_old_ttvn;
/* check if there is enough data before accessing it */
if (pskb_may_pull(skb, hdr_len + ETH_HLEN) < 0)
return 0;
/* create a copy of the skb (in case of for re-routing) to modify it. */
if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
return 0;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
ethhdr = (struct ethhdr *)(skb->data + hdr_len);
/* check if the destination client was served by this node and it is now
* roaming. In this case, it means that the node has got a ROAM_ADV
* message and that it knows the new destination in the mesh to re-route
* the packet to
*/
if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest)) {
if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
ethhdr->h_dest))
batadv_dbg_ratelimited(BATADV_DBG_TT,
bat_priv,
"Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
unicast_packet->dest,
ethhdr->h_dest);
/* at this point the mesh destination should have been
* substituted with the originator address found in the global
* table. If not, let the packet go untouched anyway because
* there is nothing the node can do
*/
return 1;
}
/* retrieve the TTVN known by this node for the packet destination. This
* value is used later to check if the node which sent (or re-routed
* last time) the packet had an updated information or not
*/
curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
orig_node = batadv_orig_hash_find(bat_priv,
unicast_packet->dest);
/* if it is not possible to find the orig_node representing the
* destination, the packet can immediately be dropped as it will
* not be possible to deliver it
*/
if (!orig_node)
return 0;
curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
batadv_orig_node_free_ref(orig_node);
}
/* check if the TTVN contained in the packet is fresher than what the
* node knows
*/
is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
if (!is_old_ttvn)
return 1;
old_ttvn = unicast_packet->ttvn;
/* the packet was forged based on outdated network information. Its
* destination can possibly be updated and forwarded towards the new
* target host
*/
if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
ethhdr->h_dest)) {
batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
"Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
unicast_packet->dest, ethhdr->h_dest,
old_ttvn, curr_ttvn);
return 1;
}
/* the packet has not been re-routed: either the destination is
* currently served by this node or there is no destination at all and
* it is possible to drop the packet
*/
if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
return 0;