batman-adv: Make orig_node->router an rcu protected pointer
The rcu protected macros rcu_dereference() and rcu_assign_pointer()
for the orig_node->router need to be used, as well as spin/rcu locking.
Otherwise we might end up using a router pointer pointing to already
freed memory.
Therefore this commit introduces the safe getter method
orig_node_get_router().
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index f212abe..b7d43ca 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -87,18 +87,20 @@
struct neigh_node *neigh_node,
unsigned char *hna_buff, int hna_buff_len)
{
- struct neigh_node *neigh_node_tmp;
+ struct neigh_node *curr_router;
+
+ curr_router = orig_node_get_router(orig_node);
/* route deleted */
- if ((orig_node->router) && (!neigh_node)) {
+ if ((curr_router) && (!neigh_node)) {
bat_dbg(DBG_ROUTES, bat_priv, "Deleting route towards: %pM\n",
orig_node->orig);
hna_global_del_orig(bat_priv, orig_node,
"originator timed out");
- /* route added */
- } else if ((!orig_node->router) && (neigh_node)) {
+ /* route added */
+ } else if ((!curr_router) && (neigh_node)) {
bat_dbg(DBG_ROUTES, bat_priv,
"Adding route towards: %pM (via %pM)\n",
@@ -106,21 +108,29 @@
hna_global_add_orig(bat_priv, orig_node,
hna_buff, hna_buff_len);
- /* route changed */
+ /* route changed */
} else {
bat_dbg(DBG_ROUTES, bat_priv,
"Changing route towards: %pM "
"(now via %pM - was via %pM)\n",
orig_node->orig, neigh_node->addr,
- orig_node->router->addr);
+ curr_router->addr);
}
+ if (curr_router)
+ 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;
- neigh_node_tmp = orig_node->router;
- orig_node->router = neigh_node;
- if (neigh_node_tmp)
- neigh_node_free_ref(neigh_node_tmp);
+
+ 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)
+ neigh_node_free_ref(curr_router);
}
@@ -128,16 +138,23 @@
struct neigh_node *neigh_node, unsigned char *hna_buff,
int hna_buff_len)
{
+ struct neigh_node *router = NULL;
if (!orig_node)
- return;
+ goto out;
- if (orig_node->router != neigh_node)
+ router = orig_node_get_router(orig_node);
+
+ if (router != neigh_node)
update_route(bat_priv, orig_node, neigh_node,
hna_buff, hna_buff_len);
/* may be just HNA changed */
else
update_HNA(bat_priv, orig_node, hna_buff, hna_buff_len);
+
+out:
+ if (router)
+ neigh_node_free_ref(router);
}
static int is_bidirectional_neigh(struct orig_node *orig_node,
@@ -288,8 +305,8 @@
struct neigh_node *neigh_node)
{
struct hlist_node *node;
- struct neigh_node *tmp_neigh_node;
- uint8_t best_tq, interference_candidate = 0;
+ struct neigh_node *tmp_neigh_node, *router = NULL;
+ uint8_t interference_candidate = 0;
spin_lock_bh(&orig_node->neigh_list_lock);
@@ -298,13 +315,12 @@
neigh_node->orig_node->primary_addr))
goto candidate_del;
- if (!orig_node->router)
+ router = orig_node_get_router(orig_node);
+ if (!router)
goto candidate_del;
- best_tq = orig_node->router->tq_avg;
-
/* ... and is good enough to be considered */
- if (neigh_node->tq_avg < best_tq - BONDING_TQ_THRESHOLD)
+ if (neigh_node->tq_avg < router->tq_avg - BONDING_TQ_THRESHOLD)
goto candidate_del;
/**
@@ -350,7 +366,9 @@
out:
spin_unlock_bh(&orig_node->neigh_list_lock);
- return;
+
+ if (router)
+ neigh_node_free_ref(router);
}
/* copy primary address for bonding */
@@ -373,6 +391,7 @@
char is_duplicate)
{
struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL;
+ struct neigh_node *router = NULL;
struct orig_node *orig_node_tmp;
struct hlist_node *node;
int tmp_hna_buff_len;
@@ -441,19 +460,18 @@
/* if this neighbor already is our next hop there is nothing
* to change */
- if (orig_node->router == neigh_node)
+ router = orig_node_get_router(orig_node);
+ if (router == neigh_node)
goto update_hna;
/* if this neighbor does not offer a better TQ we won't consider it */
- if ((orig_node->router) &&
- (orig_node->router->tq_avg > neigh_node->tq_avg))
+ if (router && (router->tq_avg > neigh_node->tq_avg))
goto update_hna;
/* if the TQ is the same and the link not more symetric we
* won't consider it either */
- if ((orig_node->router) &&
- (neigh_node->tq_avg == orig_node->router->tq_avg)) {
- orig_node_tmp = orig_node->router->orig_node;
+ if (router && (neigh_node->tq_avg == router->tq_avg)) {
+ orig_node_tmp = router->orig_node;
spin_lock_bh(&orig_node_tmp->ogm_cnt_lock);
bcast_own_sum_orig =
orig_node_tmp->bcast_own_sum[if_incoming->if_num];
@@ -474,7 +492,7 @@
goto update_gw;
update_hna:
- update_routes(bat_priv, orig_node, orig_node->router,
+ update_routes(bat_priv, orig_node, router,
hna_buff, tmp_hna_buff_len);
update_gw:
@@ -496,6 +514,8 @@
out:
if (neigh_node)
neigh_node_free_ref(neigh_node);
+ if (router)
+ neigh_node_free_ref(router);
}
/* checks whether the host restarted and is in the protection time.
@@ -603,6 +623,8 @@
struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
struct hard_iface *hard_iface;
struct orig_node *orig_neigh_node, *orig_node;
+ struct neigh_node *router = NULL, *router_router = NULL;
+ struct neigh_node *orig_neigh_router = NULL;
char has_directlink_flag;
char is_my_addr = 0, is_my_orig = 0, is_my_oldorig = 0;
char is_broadcast = 0, is_bidirectional, is_single_hop_neigh;
@@ -747,14 +769,15 @@
goto out;
}
+ router = orig_node_get_router(orig_node);
+ if (router)
+ router_router = orig_node_get_router(router->orig_node);
+
/* avoid temporary routing loops */
- if ((orig_node->router) &&
- (orig_node->router->orig_node->router) &&
- (compare_eth(orig_node->router->addr,
- batman_packet->prev_sender)) &&
+ if (router && router_router &&
+ (compare_eth(router->addr, batman_packet->prev_sender)) &&
!(compare_eth(batman_packet->orig, batman_packet->prev_sender)) &&
- (compare_eth(orig_node->router->addr,
- orig_node->router->orig_node->router->addr))) {
+ (compare_eth(router->addr, router_router->addr))) {
bat_dbg(DBG_BATMAN, bat_priv,
"Drop packet: ignoring all rebroadcast packets that "
"may make me loop (sender: %pM)\n", ethhdr->h_source);
@@ -769,9 +792,11 @@
if (!orig_neigh_node)
goto out;
+ orig_neigh_router = orig_node_get_router(orig_neigh_node);
+
/* drop packet if sender is not a direct neighbor and if we
* don't route towards it */
- if (!is_single_hop_neigh && (!orig_neigh_node->router)) {
+ if (!is_single_hop_neigh && (!orig_neigh_router)) {
bat_dbg(DBG_BATMAN, bat_priv,
"Drop packet: OGM via unknown neighbor!\n");
goto out_neigh;
@@ -825,6 +850,13 @@
if ((orig_neigh_node) && (!is_single_hop_neigh))
orig_node_free_ref(orig_neigh_node);
out:
+ if (router)
+ neigh_node_free_ref(router);
+ if (router_router)
+ neigh_node_free_ref(router_router);
+ if (orig_neigh_router)
+ neigh_node_free_ref(orig_neigh_router);
+
orig_node_free_ref(orig_node);
}
@@ -869,7 +901,7 @@
struct sk_buff *skb, size_t icmp_len)
{
struct orig_node *orig_node = NULL;
- struct neigh_node *neigh_node = NULL;
+ struct neigh_node *router = NULL;
struct icmp_packet_rr *icmp_packet;
int ret = NET_RX_DROP;
@@ -886,23 +918,13 @@
/* answer echo request (ping) */
/* get routing information */
- rcu_read_lock();
orig_node = orig_hash_find(bat_priv, icmp_packet->orig);
-
if (!orig_node)
- goto unlock;
+ goto out;
- neigh_node = orig_node->router;
-
- if (!neigh_node)
- goto unlock;
-
- if (!atomic_inc_not_zero(&neigh_node->refcount)) {
- neigh_node = NULL;
- goto unlock;
- }
-
- rcu_read_unlock();
+ router = orig_node_get_router(orig_node);
+ if (!router)
+ goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
@@ -916,15 +938,12 @@
icmp_packet->msg_type = ECHO_REPLY;
icmp_packet->ttl = TTL;
- send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
+ send_skb_packet(skb, router->if_incoming, router->addr);
ret = NET_RX_SUCCESS;
- goto out;
-unlock:
- rcu_read_unlock();
out:
- if (neigh_node)
- neigh_node_free_ref(neigh_node);
+ if (router)
+ neigh_node_free_ref(router);
if (orig_node)
orig_node_free_ref(orig_node);
return ret;
@@ -934,7 +953,7 @@
struct sk_buff *skb)
{
struct orig_node *orig_node = NULL;
- struct neigh_node *neigh_node = NULL;
+ struct neigh_node *router = NULL;
struct icmp_packet *icmp_packet;
int ret = NET_RX_DROP;
@@ -952,23 +971,13 @@
goto out;
/* get routing information */
- rcu_read_lock();
orig_node = orig_hash_find(bat_priv, icmp_packet->orig);
-
if (!orig_node)
- goto unlock;
+ goto out;
- neigh_node = orig_node->router;
-
- if (!neigh_node)
- goto unlock;
-
- if (!atomic_inc_not_zero(&neigh_node->refcount)) {
- neigh_node = NULL;
- goto unlock;
- }
-
- rcu_read_unlock();
+ router = orig_node_get_router(orig_node);
+ if (!router)
+ goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
@@ -982,15 +991,12 @@
icmp_packet->msg_type = TTL_EXCEEDED;
icmp_packet->ttl = TTL;
- send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
+ send_skb_packet(skb, router->if_incoming, router->addr);
ret = NET_RX_SUCCESS;
- goto out;
-unlock:
- rcu_read_unlock();
out:
- if (neigh_node)
- neigh_node_free_ref(neigh_node);
+ if (router)
+ neigh_node_free_ref(router);
if (orig_node)
orig_node_free_ref(orig_node);
return ret;
@@ -1003,7 +1009,7 @@
struct icmp_packet_rr *icmp_packet;
struct ethhdr *ethhdr;
struct orig_node *orig_node = NULL;
- struct neigh_node *neigh_node = NULL;
+ struct neigh_node *router = NULL;
int hdr_size = sizeof(struct icmp_packet);
int ret = NET_RX_DROP;
@@ -1050,23 +1056,13 @@
return recv_icmp_ttl_exceeded(bat_priv, skb);
/* get routing information */
- rcu_read_lock();
orig_node = orig_hash_find(bat_priv, icmp_packet->dst);
-
if (!orig_node)
- goto unlock;
+ goto out;
- neigh_node = orig_node->router;
-
- if (!neigh_node)
- goto unlock;
-
- if (!atomic_inc_not_zero(&neigh_node->refcount)) {
- neigh_node = NULL;
- goto unlock;
- }
-
- rcu_read_unlock();
+ router = orig_node_get_router(orig_node);
+ if (!router)
+ goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
@@ -1078,15 +1074,12 @@
icmp_packet->ttl--;
/* route it */
- send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
+ send_skb_packet(skb, router->if_incoming, router->addr);
ret = NET_RX_SUCCESS;
- goto out;
-unlock:
- rcu_read_unlock();
out:
- if (neigh_node)
- neigh_node_free_ref(neigh_node);
+ if (router)
+ neigh_node_free_ref(router);
if (orig_node)
orig_node_free_ref(orig_node);
return ret;
@@ -1208,7 +1201,8 @@
if (!orig_node)
return NULL;
- if (!orig_node->router)
+ router = orig_node_get_router(orig_node);
+ if (!router)
return NULL;
/* without bonding, the first node should
@@ -1217,9 +1211,8 @@
rcu_read_lock();
/* select default router to output */
- router = orig_node->router;
- router_orig = orig_node->router->orig_node;
- if (!router_orig || !atomic_inc_not_zero(&router->refcount)) {
+ router_orig = router->orig_node;
+ if (!router_orig) {
rcu_read_unlock();
return NULL;
}
@@ -1251,7 +1244,6 @@
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. */