Hi everyone,
For one thing, I've changed the orig_node->router dereference as discussed on IRC, now using an extra getter method for that to reduce the lines of code for rcu-dereferencing, rcu-locking and refcounting for the router pointer and to make it easier to keep track of the right refcounting (Patch 4/5). Note, that the previous version was pretty simple, by just using rcu_dereference() everywhere. However, this current version is a little more invasive, so would be great if someone could double check that I didn't introduce any new mem-leaks or null-pointer-dereferences due to wrong refcounting. It already took me quite some time to find and squash two bugs I had introduced with this, so there might be even more in there. I double checked it myself and also tested it in a 4 node chain toplogy vm setup, though.
For Patch 5/5, I've removed the "TQ value" from the patch subject. For the TQ window locking is definitely needed, whether tq_avg needs locking as well still needs to be checked. If so, that could be done with a separate patch though.
Patches 1,2,3 are just some smaller changes. Let me know what you think about them.
Cheers, Linus
This decreases the size of find_router() by outsourcing the router search for the bonding and interface alternating modes to their own sub functions. This shall make it easier to keep track of the correct refcounting later.
Sigend-off-by: Linus Lüssing linus.luessing@web.de --- routing.c | 176 +++++++++++++++++++++++++++++++++++-------------------------- 1 files changed, 101 insertions(+), 75 deletions(-)
diff --git a/batman-adv/routing.c b/batman-adv/routing.c index c172f5d..c00d861 100644 --- a/batman-adv/routing.c +++ b/batman-adv/routing.c @@ -1092,6 +1092,102 @@ out: 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 neigh_node *find_bond_router(struct orig_node *primary_orig, + struct hard_iface *recv_if) +{ + struct neigh_node *tmp_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 && + atomic_inc_not_zero(&tmp_neigh_node->refcount)) { + 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 neigh_node *find_ifalter_router(struct orig_node *primary_orig, + struct hard_iface *recv_if) +{ + struct neigh_node *tmp_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; + + /* if we don't have a router yet + * or this one is better, choose it. */ + if ((!router) || + (tmp_neigh_node->tq_avg > router->tq_avg)) { + /* decrement refcount of + * previously selected router */ + if (router) + neigh_node_free_ref(router); + + router = tmp_neigh_node; + atomic_inc_not_zero(&router->refcount); + } + + neigh_node_free_ref(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; +} + /* find a suitable router for this originator, and use * bonding if possible. increases the found neighbors * refcount.*/ @@ -1101,7 +1197,7 @@ struct neigh_node *find_router(struct bat_priv *bat_priv, { struct orig_node *primary_orig_node; struct orig_node *router_orig; - struct neigh_node *router, *first_candidate, *tmp_neigh_node; + struct neigh_node *router; static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0}; int bonding_enabled;
@@ -1157,82 +1253,12 @@ struct neigh_node *find_router(struct bat_priv *bat_priv, * in. */
neigh_node_free_ref(router); - first_candidate = NULL; - router = NULL;
- if (bonding_enabled) { - /* in the bonding case, send the packets in a round - * robin fashion over the remaining interfaces. */ + if (bonding_enabled) + router = find_bond_router(primary_orig_node, recv_if); + else + router = find_ifalter_router(primary_orig_node, recv_if);
- list_for_each_entry_rcu(tmp_neigh_node, - &primary_orig_node->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 && - atomic_inc_not_zero(&tmp_neigh_node->refcount)) { - 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) { - rcu_read_unlock(); - return NULL; - } - - /* selected should point to the next element - * after the current router */ - spin_lock_bh(&primary_orig_node->neigh_list_lock); - /* this is a list_move(), which unfortunately - * does not exist as rcu version */ - list_del_rcu(&primary_orig_node->bond_list); - list_add_rcu(&primary_orig_node->bond_list, - &router->bonding_list); - spin_unlock_bh(&primary_orig_node->neigh_list_lock); - - } else { - /* if bonding is disabled, use the best of the - * remaining candidates which are not using - * this interface. */ - list_for_each_entry_rcu(tmp_neigh_node, - &primary_orig_node->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; - - /* if we don't have a router yet - * or this one is better, choose it. */ - if ((!router) || - (tmp_neigh_node->tq_avg > router->tq_avg)) { - /* decrement refcount of - * previously selected router */ - if (router) - neigh_node_free_ref(router); - - router = tmp_neigh_node; - atomic_inc_not_zero(&router->refcount); - } - - neigh_node_free_ref(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; - } return_router: rcu_read_unlock(); return router;
Make the return value explicit instead of (void *).
Signed-off-by: Linus Lüssing linus.luessing@web.de --- gateway_client.c | 2 +- gateway_client.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/batman-adv/gateway_client.c b/batman-adv/gateway_client.c index 3cc4355..27b87ad 100644 --- a/batman-adv/gateway_client.c +++ b/batman-adv/gateway_client.c @@ -42,7 +42,7 @@ static void gw_node_free_ref(struct gw_node *gw_node) call_rcu(&gw_node->rcu, gw_node_free_rcu); }
-void *gw_get_selected(struct bat_priv *bat_priv) +struct orig_node *gw_get_selected(struct bat_priv *bat_priv) { struct gw_node *curr_gateway_tmp; struct orig_node *orig_node = NULL; diff --git a/batman-adv/gateway_client.h b/batman-adv/gateway_client.h index 2aa4391..97c31d1 100644 --- a/batman-adv/gateway_client.h +++ b/batman-adv/gateway_client.h @@ -24,7 +24,7 @@
void gw_deselect(struct bat_priv *bat_priv); void gw_election(struct bat_priv *bat_priv); -void *gw_get_selected(struct bat_priv *bat_priv); +struct orig_node *gw_get_selected(struct bat_priv *bat_priv); void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node); void gw_node_update(struct bat_priv *bat_priv, struct orig_node *orig_node, uint8_t new_gwflags);
gw_get_selected() can get us the desired orig_node directly, therefore reusing that function in gw_check_election().
Signed-off-by: Linus Lüssing linus.luessing@web.de --- gateway_client.c | 23 ++++++++++++----------- 1 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/batman-adv/gateway_client.c b/batman-adv/gateway_client.c index 27b87ad..879ac15 100644 --- a/batman-adv/gateway_client.c +++ b/batman-adv/gateway_client.c @@ -23,6 +23,7 @@ #include "gateway_client.h" #include "gateway_common.h" #include "hard-interface.h" +#include "originator.h" #include <linux/ip.h> #include <linux/ipv6.h> #include <linux/udp.h> @@ -203,28 +204,25 @@ void gw_election(struct bat_priv *bat_priv)
void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node) { - struct gw_node *curr_gateway_tmp; + struct orig_node *curr_gw_orig; 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(); - curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw); - if (!curr_gateway_tmp) - goto out_rcu; - - if (!curr_gateway_tmp->orig_node) - goto deselect_rcu; - - if (!curr_gateway_tmp->orig_node->router) + if (!curr_gw_orig->router) goto deselect_rcu;
/* this node already is the gateway */ - if (curr_gateway_tmp->orig_node == orig_node) + if (curr_gw_orig == orig_node) goto out_rcu;
if (!orig_node->router) goto out_rcu;
- gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg; + gw_tq_avg = curr_gw_orig->router->tq_avg; rcu_read_unlock();
orig_tq_avg = orig_node->router->tq_avg; @@ -255,6 +253,9 @@ deselect_rcu: deselect: gw_deselect(bat_priv); out: + if (curr_gw_orig) + orig_node_free_ref(curr_gw_orig); + return; }
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 --- gateway_client.c | 78 ++++++++++++++++++------------ icmp_socket.c | 18 +------ originator.c | 25 +++++++++- originator.h | 1 + routing.c | 139 +++++++++++++++++++++++------------------------------ send.c | 19 +++++--- types.h | 4 +- vis.c | 70 +++++++++++++-------------- 8 files changed, 180 insertions(+), 174 deletions(-)
diff --git a/batman-adv/gateway_client.c b/batman-adv/gateway_client.c index 879ac15..d41ae97 100644 --- a/batman-adv/gateway_client.c +++ b/batman-adv/gateway_client.c @@ -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; @@ -133,26 +134,28 @@ 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) + router = orig_node_get_router(gw_node->orig_node); + if (!router) continue;
- if (gw_node->deleted) + if (gw_node->deleted) { + neigh_node_free_ref(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;
@@ -164,19 +167,25 @@ 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 - " @@ -187,45 +196,47 @@ 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; + goto out;
- if (!orig_node->router) - goto out_rcu; + router_orig = orig_node_get_router(orig_node); + if (!router_orig) + goto out;
- gw_tq_avg = curr_gw_orig->router->tq_avg; - rcu_read_unlock(); - - 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) @@ -243,18 +254,16 @@ 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; } @@ -366,19 +375,23 @@ 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"), @@ -386,6 +399,8 @@ static int _write_buffer_text(struct bat_priv *bat_priv, (up > 2048 ? "MBit" : "KBit"));
rcu_read_unlock(); + neigh_node_free_ref(router); +out: return ret; }
@@ -423,10 +438,9 @@ int gw_client_seq_print_text(struct seq_file *seq, void *offset) if (gw_node->deleted) continue;
- if (!gw_node->orig_node->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(); diff --git a/batman-adv/icmp_socket.c b/batman-adv/icmp_socket.c index 34ce56c..49079c2 100644 --- a/batman-adv/icmp_socket.c +++ b/batman-adv/icmp_socket.c @@ -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; @@ -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); diff --git a/batman-adv/originator.c b/batman-adv/originator.c index 0b91330..4989bbb 100644 --- a/batman-adv/originator.c +++ b/batman-adv/originator.c @@ -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, @@ -421,24 +436,28 @@ 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) + if (neigh_node->tq_avg == 0) { + neigh_node_free_ref(neigh_node); continue; + }
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);
+ neigh_node_free_ref(neigh_node); + hlist_for_each_entry_rcu(neigh_node, node_tmp, &orig_node->neigh_list, list) { seq_printf(seq, " %pM (%3i)", neigh_node->addr, diff --git a/batman-adv/originator.h b/batman-adv/originator.h index 5cc0110..e1d641f 100644 --- a/batman-adv/originator.h +++ b/batman-adv/originator.h @@ -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); diff --git a/batman-adv/routing.c b/batman-adv/routing.c index c00d861..9780a62 100644 --- a/batman-adv/routing.c +++ b/batman-adv/routing.c @@ -89,8 +89,10 @@ static void update_route(struct bat_priv *bat_priv, { struct neigh_node *neigh_node_tmp;
+ neigh_node_tmp = orig_node_get_router(orig_node); + /* route deleted */ - if ((orig_node->router) && (!neigh_node)) { + if ((neigh_node_tmp) && (!neigh_node)) {
bat_dbg(DBG_ROUTES, bat_priv, "Deleting route towards: %pM\n", orig_node->orig); @@ -98,7 +100,7 @@ static void update_route(struct bat_priv *bat_priv, "originator timed out");
/* route added */ - } else if ((!orig_node->router) && (neigh_node)) { + } else if ((!neigh_node_tmp) && (neigh_node)) {
bat_dbg(DBG_ROUTES, bat_priv, "Adding route towards: %pM (via %pM)\n", @@ -112,13 +114,16 @@ static void update_route(struct bat_priv *bat_priv, "Changing route towards: %pM " "(now via %pM - was via %pM)\n", orig_node->orig, neigh_node->addr, - orig_node->router->addr); + neigh_node_tmp->addr); }
if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount)) neigh_node = NULL; - neigh_node_tmp = orig_node->router; - orig_node->router = neigh_node; + + spin_lock_bh(&orig_node->neigh_list_lock); + rcu_assign_pointer(orig_node->router, neigh_node); + spin_unlock_bh(&orig_node->neigh_list_lock); + if (neigh_node_tmp) neigh_node_free_ref(neigh_node_tmp); } @@ -128,16 +133,21 @@ void update_routes(struct bat_priv *bat_priv, struct orig_node *orig_node, struct neigh_node *neigh_node, unsigned char *hna_buff, int hna_buff_len) { + struct neigh_node *router = orig_node_get_router(orig_node);
if (!orig_node) return;
- if (orig_node->router != neigh_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); + + if (router) + neigh_node_free_ref(router); }
static int is_bidirectional_neigh(struct orig_node *orig_node, @@ -288,8 +298,8 @@ static void bonding_candidate_add(struct orig_node *orig_node, 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 +308,12 @@ static void bonding_candidate_add(struct orig_node *orig_node, 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 +359,9 @@ candidate_del:
out: spin_unlock_bh(&orig_node->neigh_list_lock); - return; + + if (router) + neigh_node_free_ref(router); }
/* copy primary address for bonding */ @@ -372,7 +383,8 @@ static void update_orig(struct bat_priv *bat_priv, unsigned char *hna_buff, int hna_buff_len, char is_duplicate) { - struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL; + struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL, + *router = NULL; struct orig_node *orig_node_tmp; struct hlist_node *node; int tmp_hna_buff_len; @@ -441,19 +453,18 @@ static void update_orig(struct bat_priv *bat_priv,
/* 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 +485,7 @@ static void update_orig(struct bat_priv *bat_priv, 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 +507,8 @@ unlock: 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 +616,7 @@ void receive_bat_packet(struct ethhdr *ethhdr, 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; 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 +761,15 @@ void receive_bat_packet(struct ethhdr *ethhdr, 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); @@ -825,6 +840,11 @@ out_neigh: 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); + orig_node_free_ref(orig_node); }
@@ -886,23 +906,13 @@ static int recv_my_icmp_packet(struct bat_priv *bat_priv,
/* 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; - - neigh_node = orig_node->router; + goto out;
+ 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 out;
/* create a copy of the skb, if needed, to modify it. */ if (skb_cow(skb, sizeof(struct ethhdr)) < 0) @@ -918,10 +928,7 @@ static int recv_my_icmp_packet(struct bat_priv *bat_priv,
send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr); ret = NET_RX_SUCCESS; - goto out;
-unlock: - rcu_read_unlock(); out: if (neigh_node) neigh_node_free_ref(neigh_node); @@ -952,23 +959,13 @@ static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv, goto out;
/* get routing information */ - rcu_read_lock(); orig_node = orig_hash_find(bat_priv, icmp_packet->orig); - if (!orig_node) - goto unlock; - - neigh_node = orig_node->router; + goto out;
+ 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 out;
/* create a copy of the skb, if needed, to modify it. */ if (skb_cow(skb, sizeof(struct ethhdr)) < 0) @@ -984,10 +981,7 @@ static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv,
send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr); ret = NET_RX_SUCCESS; - goto out;
-unlock: - rcu_read_unlock(); out: if (neigh_node) neigh_node_free_ref(neigh_node); @@ -1050,23 +1044,13 @@ int recv_icmp_packet(struct sk_buff *skb, struct hard_iface *recv_if) 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; - - neigh_node = orig_node->router; + goto out;
+ 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 out;
/* create a copy of the skb, if needed, to modify it. */ if (skb_cow(skb, sizeof(struct ethhdr)) < 0) @@ -1080,10 +1064,7 @@ int recv_icmp_packet(struct sk_buff *skb, struct hard_iface *recv_if) /* route it */ send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr); ret = NET_RX_SUCCESS; - goto out;
-unlock: - rcu_read_unlock(); out: if (neigh_node) neigh_node_free_ref(neigh_node); @@ -1204,7 +1185,8 @@ struct neigh_node *find_router(struct bat_priv *bat_priv, 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 @@ -1213,9 +1195,8 @@ struct neigh_node *find_router(struct bat_priv *bat_priv,
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; } diff --git a/batman-adv/send.c b/batman-adv/send.c index d49e54d..e78670c 100644 --- a/batman-adv/send.c +++ b/batman-adv/send.c @@ -308,6 +308,7 @@ void schedule_forward_packet(struct orig_node *orig_node, struct hard_iface *if_incoming) { struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface); + struct neigh_node *router; unsigned char in_tq, in_ttl, tq_avg = 0; unsigned long send_time;
@@ -316,6 +317,8 @@ void schedule_forward_packet(struct orig_node *orig_node, return; }
+ router = orig_node_get_router(orig_node); + in_tq = batman_packet->tq; in_ttl = batman_packet->ttl;
@@ -324,20 +327,22 @@ void schedule_forward_packet(struct orig_node *orig_node,
/* rebroadcast tq of our best ranking neighbor to ensure the rebroadcast * of our best tq value */ - if ((orig_node->router) && (orig_node->router->tq_avg != 0)) { + if (router && router->tq_avg != 0) {
/* rebroadcast ogm of best ranking neighbor as is */ - if (!compare_eth(orig_node->router->addr, ethhdr->h_source)) { - batman_packet->tq = orig_node->router->tq_avg; + if (!compare_eth(router->addr, ethhdr->h_source)) { + batman_packet->tq = router->tq_avg;
- if (orig_node->router->last_ttl) - batman_packet->ttl = orig_node->router->last_ttl - - 1; + if (router->last_ttl) + batman_packet->ttl = router->last_ttl - 1; }
- tq_avg = orig_node->router->tq_avg; + tq_avg = router->tq_avg; }
+ if (router) + neigh_node_free_ref(router); + /* apply hop penalty */ batman_packet->tq = hop_penalty(batman_packet->tq, bat_priv);
diff --git a/batman-adv/types.h b/batman-adv/types.h index 83445cf..1854cbb 100644 --- a/batman-adv/types.h +++ b/batman-adv/types.h @@ -67,7 +67,7 @@ struct hard_iface { struct orig_node { uint8_t orig[ETH_ALEN]; uint8_t primary_addr[ETH_ALEN]; - struct neigh_node *router; + struct neigh_node __rcu *router; /* rcu protected pointer */ unsigned long *bcast_own; uint8_t *bcast_own_sum; unsigned long last_valid; @@ -83,7 +83,7 @@ struct orig_node { uint32_t last_bcast_seqno; struct hlist_head neigh_list; struct list_head frag_list; - spinlock_t neigh_list_lock; /* protects neighbor list */ + spinlock_t neigh_list_lock; /* protects neigh_list and router */ atomic_t refcount; struct rcu_head rcu; struct hlist_node hash_entry; diff --git a/batman-adv/vis.c b/batman-adv/vis.c index f90212f..3efd1ea 100644 --- a/batman-adv/vis.c +++ b/batman-adv/vis.c @@ -558,6 +558,7 @@ static int find_best_vis_server(struct bat_priv *bat_priv, struct vis_info *info) { struct hashtable_t *hash = bat_priv->orig_hash; + struct neigh_node *router; struct hlist_node *node; struct hlist_head *head; struct orig_node *orig_node; @@ -571,13 +572,17 @@ static int find_best_vis_server(struct bat_priv *bat_priv,
rcu_read_lock(); hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) { - if ((orig_node) && (orig_node->router) && - (orig_node->flags & VIS_SERVER) && - (orig_node->router->tq_avg > best_tq)) { - best_tq = orig_node->router->tq_avg; + router = orig_node_get_router(orig_node); + if (!router) + continue; + + if ((orig_node->flags & VIS_SERVER) && + (router->tq_avg > best_tq)) { + best_tq = router->tq_avg; memcpy(packet->target_orig, orig_node->orig, ETH_ALEN); } + neigh_node_free_ref(router); } rcu_read_unlock(); } @@ -633,19 +638,16 @@ static int generate_vis_packet(struct bat_priv *bat_priv)
rcu_read_lock(); hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) { - neigh_node = orig_node->router; - + neigh_node = orig_node_get_router(orig_node); if (!neigh_node) continue;
- if (!compare_eth(neigh_node->addr, orig_node->orig)) - continue; - - if (neigh_node->if_incoming->if_status != IF_ACTIVE) - continue; - - if (neigh_node->tq_avg < 1) + if (!compare_eth(neigh_node->addr, orig_node->orig) || + neigh_node->if_incoming->if_status != IF_ACTIVE || + neigh_node->tq_avg < 1) { + neigh_node_free_ref(neigh_node); continue; + }
/* fill one entry into buffer. */ entry = (struct vis_info_entry *) @@ -657,6 +659,8 @@ static int generate_vis_packet(struct bat_priv *bat_priv) entry->quality = neigh_node->tq_avg; packet->entries++;
+ neigh_node_free_ref(neigh_node); + if (vis_packet_full(info)) goto unlock; } @@ -725,6 +729,7 @@ static void purge_vis_packets(struct bat_priv *bat_priv) static void broadcast_vis_packet(struct bat_priv *bat_priv, struct vis_info *info) { + struct neigh_node *router; struct hashtable_t *hash = bat_priv->orig_hash; struct hlist_node *node; struct hlist_head *head; @@ -745,19 +750,26 @@ static void broadcast_vis_packet(struct bat_priv *bat_priv, rcu_read_lock(); hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) { /* if it's a vis server and reachable, send it. */ - if ((!orig_node) || (!orig_node->router)) - continue; if (!(orig_node->flags & VIS_SERVER)) continue; + + router = orig_node_get_router(orig_node); + if (!router) + continue; + /* don't send it if we already received the packet from - * this node. */ + * this node. */ if (recv_list_is_in(bat_priv, &info->recv_list, - orig_node->orig)) + orig_node->orig)) { + neigh_node_free_ref(router); continue; + }
memcpy(packet->target_orig, orig_node->orig, ETH_ALEN); - hard_iface = orig_node->router->if_incoming; - memcpy(dstaddr, orig_node->router->addr, ETH_ALEN); + hard_iface = router->if_incoming; + memcpy(dstaddr, router->addr, ETH_ALEN); + + neigh_node_free_ref(router);
skb = skb_clone(info->skb_packet, GFP_ATOMIC); if (skb) @@ -778,33 +790,19 @@ static void unicast_vis_packet(struct bat_priv *bat_priv,
packet = (struct vis_packet *)info->skb_packet->data;
- rcu_read_lock(); orig_node = orig_hash_find(bat_priv, packet->target_orig); - if (!orig_node) - goto unlock; - - neigh_node = orig_node->router; + goto out;
+ 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 out;
skb = skb_clone(info->skb_packet, GFP_ATOMIC); if (skb) send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
- goto out; - -unlock: - rcu_read_unlock(); out: if (neigh_node) neigh_node_free_ref(neigh_node);
Signed-off-by: Linus Lüssing linus.luessing@web.de --- originator.c | 1 + routing.c | 4 ++++ types.h | 1 + 3 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/batman-adv/originator.c b/batman-adv/originator.c index 4989bbb..4905619 100644 --- a/batman-adv/originator.c +++ b/batman-adv/originator.c @@ -102,6 +102,7 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
INIT_HLIST_NODE(&neigh_node->list); INIT_LIST_HEAD(&neigh_node->bonding_list); + spin_lock_init(&neigh_node->tq_lock);
memcpy(neigh_node->addr, neigh, ETH_ALEN); neigh_node->orig_node = orig_neigh_node; diff --git a/batman-adv/routing.c b/batman-adv/routing.c index 9780a62..cd578d4 100644 --- a/batman-adv/routing.c +++ b/batman-adv/routing.c @@ -408,10 +408,12 @@ static void update_orig(struct bat_priv *bat_priv, if (is_duplicate) continue;
+ spin_lock_bh(&tmp_neigh_node->tq_lock); ring_buffer_set(tmp_neigh_node->tq_recv, &tmp_neigh_node->tq_index, 0); tmp_neigh_node->tq_avg = ring_buffer_avg(tmp_neigh_node->tq_recv); + spin_unlock_bh(&tmp_neigh_node->tq_lock); }
if (!neigh_node) { @@ -436,10 +438,12 @@ static void update_orig(struct bat_priv *bat_priv, orig_node->flags = batman_packet->flags; neigh_node->last_valid = jiffies;
+ spin_lock_bh(&neigh_node->tq_lock); ring_buffer_set(neigh_node->tq_recv, &neigh_node->tq_index, batman_packet->tq); neigh_node->tq_avg = ring_buffer_avg(neigh_node->tq_recv); + spin_unlock_bh(&neigh_node->tq_lock);
if (!is_duplicate) { orig_node->last_ttl = batman_packet->ttl; diff --git a/batman-adv/types.h b/batman-adv/types.h index 1854cbb..091476d 100644 --- a/batman-adv/types.h +++ b/batman-adv/types.h @@ -125,6 +125,7 @@ struct neigh_node { struct rcu_head rcu; struct orig_node *orig_node; struct hard_iface *if_incoming; + spinlock_t tq_lock; /* protects: tq_recv, tq_index */ };
Hi,
For one thing, I've changed the orig_node->router dereference as discussed on IRC, now using an extra getter method for that to reduce the lines of code for rcu-dereferencing, rcu-locking and refcounting for the router pointer and to make it easier to keep track of the right refcounting (Patch 4/5). Note, that the previous version was pretty simple, by just using rcu_dereference() everywhere. However, this current version is a little more invasive, so would be great if someone could double check that I didn't introduce any new mem-leaks or null-pointer-dereferences due to wrong refcounting. It already took me quite some time to find and squash two bugs I had introduced with this, so there might be even more in there. I double checked it myself and also tested it in a 4 node chain toplogy vm setup, though.
after reviewing these patches I made some modifications before committing them in revision 1956-1960.
Thanks, Marek
b.a.t.m.a.n@lists.open-mesh.org
-
Linus Lüssing -
Marek Lindner