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batman-adv: Make orig_node->router an rcu protected pointer
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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 <[email protected]>
Signed-off-by: Marek Lindner <[email protected]>
Signed-off-by: Sven Eckelmann <[email protected]>
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@T-X @ecsv
T-X authored and ecsv committed Apr 17, 2011
1 parent 57f0c07 commit e1a5382
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Showing 8 changed files with 232 additions and 212 deletions.
80 changes: 48 additions & 32 deletions net/batman-adv/gateway_client.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,7 @@ void gw_election(struct bat_priv *bat_priv)
{
struct hlist_node *node;
struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
struct neigh_node *router;
uint8_t max_tq = 0;
uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
int down, up;
Expand Down Expand Up @@ -133,26 +134,26 @@ void gw_election(struct bat_priv *bat_priv)
}

hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
if (!gw_node->orig_node->router)
if (gw_node->deleted)
continue;

if (gw_node->deleted)
router = orig_node_get_router(gw_node->orig_node);
if (!router)
continue;

switch (atomic_read(&bat_priv->gw_sel_class)) {
case 1: /* fast connection */
gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
&down, &up);

tmp_gw_factor = (gw_node->orig_node->router->tq_avg *
gw_node->orig_node->router->tq_avg *
tmp_gw_factor = (router->tq_avg * router->tq_avg *
down * 100 * 100) /
(TQ_LOCAL_WINDOW_SIZE *
TQ_LOCAL_WINDOW_SIZE * 64);

if ((tmp_gw_factor > max_gw_factor) ||
((tmp_gw_factor == max_gw_factor) &&
(gw_node->orig_node->router->tq_avg > max_tq)))
(router->tq_avg > max_tq)))
curr_gw_tmp = gw_node;
break;

Expand All @@ -164,19 +165,25 @@ void gw_election(struct bat_priv *bat_priv)
* soon as a better gateway appears which has
* $routing_class more tq points)
**/
if (gw_node->orig_node->router->tq_avg > max_tq)
if (router->tq_avg > max_tq)
curr_gw_tmp = gw_node;
break;
}

if (gw_node->orig_node->router->tq_avg > max_tq)
max_tq = gw_node->orig_node->router->tq_avg;
if (router->tq_avg > max_tq)
max_tq = router->tq_avg;

if (tmp_gw_factor > max_gw_factor)
max_gw_factor = tmp_gw_factor;

neigh_node_free_ref(router);
}

if (curr_gw != curr_gw_tmp) {
router = orig_node_get_router(curr_gw_tmp->orig_node);
if (!router)
goto out;

if ((curr_gw) && (!curr_gw_tmp))
bat_dbg(DBG_BATMAN, bat_priv,
"Removing selected gateway - "
Expand All @@ -187,45 +194,47 @@ void gw_election(struct bat_priv *bat_priv)
"(gw_flags: %i, tq: %i)\n",
curr_gw_tmp->orig_node->orig,
curr_gw_tmp->orig_node->gw_flags,
curr_gw_tmp->orig_node->router->tq_avg);
router->tq_avg);
else
bat_dbg(DBG_BATMAN, bat_priv,
"Changing route to gateway %pM "
"(gw_flags: %i, tq: %i)\n",
curr_gw_tmp->orig_node->orig,
curr_gw_tmp->orig_node->gw_flags,
curr_gw_tmp->orig_node->router->tq_avg);
router->tq_avg);

neigh_node_free_ref(router);
gw_select(bat_priv, curr_gw_tmp);
}

out:
rcu_read_unlock();
}

void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
{
struct orig_node *curr_gw_orig;
struct neigh_node *router_gw = NULL, *router_orig = NULL;
uint8_t gw_tq_avg, orig_tq_avg;

curr_gw_orig = gw_get_selected(bat_priv);
if (!curr_gw_orig)
goto deselect;

rcu_read_lock();
if (!curr_gw_orig->router)
goto deselect_rcu;
router_gw = orig_node_get_router(curr_gw_orig);
if (!router_gw)
goto deselect;

/* this node already is the gateway */
if (curr_gw_orig == orig_node)
goto out_rcu;

if (!orig_node->router)
goto out_rcu;
goto out;

gw_tq_avg = curr_gw_orig->router->tq_avg;
rcu_read_unlock();
router_orig = orig_node_get_router(orig_node);
if (!router_orig)
goto out;

orig_tq_avg = orig_node->router->tq_avg;
gw_tq_avg = router_gw->tq_avg;
orig_tq_avg = router_orig->tq_avg;

/* the TQ value has to be better */
if (orig_tq_avg < gw_tq_avg)
Expand All @@ -243,18 +252,16 @@ void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
"Restarting gateway selection: better gateway found (tq curr: "
"%i, tq new: %i)\n",
gw_tq_avg, orig_tq_avg);
goto deselect;

out_rcu:
rcu_read_unlock();
goto out;
deselect_rcu:
rcu_read_unlock();
deselect:
gw_deselect(bat_priv);
out:
if (curr_gw_orig)
orig_node_free_ref(curr_gw_orig);
if (router_gw)
neigh_node_free_ref(router_gw);
if (router_orig)
neigh_node_free_ref(router_orig);

return;
}
Expand Down Expand Up @@ -362,30 +369,39 @@ void gw_node_purge(struct bat_priv *bat_priv)
spin_unlock_bh(&bat_priv->gw_list_lock);
}

/**
* fails if orig_node has no router
*/
static int _write_buffer_text(struct bat_priv *bat_priv,
struct seq_file *seq, struct gw_node *gw_node)
{
struct gw_node *curr_gw;
int down, up, ret;
struct neigh_node *router;
int down, up, ret = -1;

gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);

router = orig_node_get_router(gw_node->orig_node);
if (!router)
goto out;

rcu_read_lock();
curr_gw = rcu_dereference(bat_priv->curr_gw);

ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
(curr_gw == gw_node ? "=>" : " "),
gw_node->orig_node->orig,
gw_node->orig_node->router->tq_avg,
gw_node->orig_node->router->addr,
gw_node->orig_node->router->if_incoming->net_dev->name,
router->tq_avg, router->addr,
router->if_incoming->net_dev->name,
gw_node->orig_node->gw_flags,
(down > 2048 ? down / 1024 : down),
(down > 2048 ? "MBit" : "KBit"),
(up > 2048 ? up / 1024 : up),
(up > 2048 ? "MBit" : "KBit"));

rcu_read_unlock();
neigh_node_free_ref(router);
out:
return ret;
}

Expand Down Expand Up @@ -423,10 +439,10 @@ int gw_client_seq_print_text(struct seq_file *seq, void *offset)
if (gw_node->deleted)
continue;

if (!gw_node->orig_node->router)
/* fails if orig_node has no router */
if (_write_buffer_text(bat_priv, seq, gw_node) < 0)
continue;

_write_buffer_text(bat_priv, seq, gw_node);
gw_count++;
}
rcu_read_unlock();
Expand Down
18 changes: 3 additions & 15 deletions net/batman-adv/icmp_socket.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -218,23 +218,13 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff,
if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
goto dst_unreach;

rcu_read_lock();
orig_node = orig_hash_find(bat_priv, icmp_packet->dst);

if (!orig_node)
goto unlock;

neigh_node = orig_node->router;
goto dst_unreach;

neigh_node = orig_node_get_router(orig_node);
if (!neigh_node)
goto unlock;

if (!atomic_inc_not_zero(&neigh_node->refcount)) {
neigh_node = NULL;
goto unlock;
}

rcu_read_unlock();
goto dst_unreach;

if (!neigh_node->if_incoming)
goto dst_unreach;
Expand All @@ -252,8 +242,6 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff,
send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
goto out;

unlock:
rcu_read_unlock();
dst_unreach:
icmp_packet->msg_type = DESTINATION_UNREACHABLE;
bat_socket_add_packet(socket_client, icmp_packet, packet_len);
Expand Down
37 changes: 28 additions & 9 deletions net/batman-adv/originator.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,21 @@ void neigh_node_free_ref(struct neigh_node *neigh_node)
call_rcu(&neigh_node->rcu, neigh_node_free_rcu);
}

/* increases the refcounter of a found router */
struct neigh_node *orig_node_get_router(struct orig_node *orig_node)
{
struct neigh_node *router;

rcu_read_lock();
router = rcu_dereference(orig_node->router);

if (router && !atomic_inc_not_zero(&router->refcount))
router = NULL;

rcu_read_unlock();
return router;
}

struct neigh_node *create_neighbor(struct orig_node *orig_node,
struct orig_node *orig_neigh_node,
uint8_t *neigh,
Expand Down Expand Up @@ -390,7 +405,7 @@ int orig_seq_print_text(struct seq_file *seq, void *offset)
struct hlist_node *node, *node_tmp;
struct hlist_head *head;
struct orig_node *orig_node;
struct neigh_node *neigh_node;
struct neigh_node *neigh_node, *neigh_node_tmp;
int batman_count = 0;
int last_seen_secs;
int last_seen_msecs;
Expand Down Expand Up @@ -421,37 +436,41 @@ int orig_seq_print_text(struct seq_file *seq, void *offset)

rcu_read_lock();
hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
if (!orig_node->router)
neigh_node = orig_node_get_router(orig_node);
if (!neigh_node)
continue;

if (orig_node->router->tq_avg == 0)
continue;
if (neigh_node->tq_avg == 0)
goto next;

last_seen_secs = jiffies_to_msecs(jiffies -
orig_node->last_valid) / 1000;
last_seen_msecs = jiffies_to_msecs(jiffies -
orig_node->last_valid) % 1000;

neigh_node = orig_node->router;
seq_printf(seq, "%pM %4i.%03is (%3i) %pM [%10s]:",
orig_node->orig, last_seen_secs,
last_seen_msecs, neigh_node->tq_avg,
neigh_node->addr,
neigh_node->if_incoming->net_dev->name);

hlist_for_each_entry_rcu(neigh_node, node_tmp,
hlist_for_each_entry_rcu(neigh_node_tmp, node_tmp,
&orig_node->neigh_list, list) {
seq_printf(seq, " %pM (%3i)", neigh_node->addr,
neigh_node->tq_avg);
seq_printf(seq, " %pM (%3i)",
neigh_node_tmp->addr,
neigh_node_tmp->tq_avg);
}

seq_printf(seq, "\n");
batman_count++;

next:
neigh_node_free_ref(neigh_node);
}
rcu_read_unlock();
}

if ((batman_count == 0))
if (batman_count == 0)
seq_printf(seq, "No batman nodes in range ...\n");

return 0;
Expand Down
1 change: 1 addition & 0 deletions net/batman-adv/originator.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
uint8_t *neigh,
struct hard_iface *if_incoming);
void neigh_node_free_ref(struct neigh_node *neigh_node);
struct neigh_node *orig_node_get_router(struct orig_node *orig_node);
int orig_seq_print_text(struct seq_file *seq, void *offset);
int orig_hash_add_if(struct hard_iface *hard_iface, int max_if_num);
int orig_hash_del_if(struct hard_iface *hard_iface, int max_if_num);
Expand Down
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