diff options
Diffstat (limited to 'net/netfilter/nfnetlink_log.c')
-rw-r--r-- | net/netfilter/nfnetlink_log.c | 73 |
1 files changed, 43 insertions, 30 deletions
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c index fc9a211e629e..6a1572b0ab41 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -66,9 +66,10 @@ struct nfulnl_instance { u_int16_t group_num; /* number of this queue */ u_int16_t flags; u_int8_t copy_mode; + struct rcu_head rcu; }; -static DEFINE_RWLOCK(instances_lock); +static DEFINE_SPINLOCK(instances_lock); static atomic_t global_seq; #define INSTANCE_BUCKETS 16 @@ -88,7 +89,7 @@ __instance_lookup(u_int16_t group_num) struct nfulnl_instance *inst; head = &instance_table[instance_hashfn(group_num)]; - hlist_for_each_entry(inst, pos, head, hlist) { + hlist_for_each_entry_rcu(inst, pos, head, hlist) { if (inst->group_num == group_num) return inst; } @@ -106,22 +107,26 @@ instance_lookup_get(u_int16_t group_num) { struct nfulnl_instance *inst; - read_lock_bh(&instances_lock); + rcu_read_lock_bh(); inst = __instance_lookup(group_num); - if (inst) - instance_get(inst); - read_unlock_bh(&instances_lock); + if (inst && !atomic_inc_not_zero(&inst->use)) + inst = NULL; + rcu_read_unlock_bh(); return inst; } +static void nfulnl_instance_free_rcu(struct rcu_head *head) +{ + kfree(container_of(head, struct nfulnl_instance, rcu)); + module_put(THIS_MODULE); +} + static void instance_put(struct nfulnl_instance *inst) { - if (inst && atomic_dec_and_test(&inst->use)) { - kfree(inst); - module_put(THIS_MODULE); - } + if (inst && atomic_dec_and_test(&inst->use)) + call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu); } static void nfulnl_timer(unsigned long data); @@ -132,7 +137,7 @@ instance_create(u_int16_t group_num, int pid) struct nfulnl_instance *inst; int err; - write_lock_bh(&instances_lock); + spin_lock_bh(&instances_lock); if (__instance_lookup(group_num)) { err = -EEXIST; goto out_unlock; @@ -166,32 +171,37 @@ instance_create(u_int16_t group_num, int pid) inst->copy_mode = NFULNL_COPY_PACKET; inst->copy_range = NFULNL_COPY_RANGE_MAX; - hlist_add_head(&inst->hlist, + hlist_add_head_rcu(&inst->hlist, &instance_table[instance_hashfn(group_num)]); - write_unlock_bh(&instances_lock); + spin_unlock_bh(&instances_lock); return inst; out_unlock: - write_unlock_bh(&instances_lock); + spin_unlock_bh(&instances_lock); return ERR_PTR(err); } static void __nfulnl_flush(struct nfulnl_instance *inst); +/* called with BH disabled */ static void __instance_destroy(struct nfulnl_instance *inst) { /* first pull it out of the global list */ - hlist_del(&inst->hlist); + hlist_del_rcu(&inst->hlist); /* then flush all pending packets from skb */ - spin_lock_bh(&inst->lock); + spin_lock(&inst->lock); + + /* lockless readers wont be able to use us */ + inst->copy_mode = NFULNL_COPY_DISABLED; + if (inst->skb) __nfulnl_flush(inst); - spin_unlock_bh(&inst->lock); + spin_unlock(&inst->lock); /* and finally put the refcount */ instance_put(inst); @@ -200,9 +210,9 @@ __instance_destroy(struct nfulnl_instance *inst) static inline void instance_destroy(struct nfulnl_instance *inst) { - write_lock_bh(&instances_lock); + spin_lock_bh(&instances_lock); __instance_destroy(inst); - write_unlock_bh(&instances_lock); + spin_unlock_bh(&instances_lock); } static int @@ -403,8 +413,9 @@ __build_packet_message(struct nfulnl_instance *inst, NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSINDEV, htonl(indev->ifindex)); /* this is the bridge group "brX" */ + /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */ NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_INDEV, - htonl(indev->br_port->br->dev->ifindex)); + htonl(br_port_get_rcu(indev)->br->dev->ifindex)); } else { /* Case 2: indev is bridge group, we need to look for * physical device (when called from ipv4) */ @@ -430,8 +441,9 @@ __build_packet_message(struct nfulnl_instance *inst, NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, htonl(outdev->ifindex)); /* this is the bridge group "brX" */ + /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */ NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_OUTDEV, - htonl(outdev->br_port->br->dev->ifindex)); + htonl(br_port_get_rcu(outdev)->br->dev->ifindex)); } else { /* Case 2: indev is a bridge group, we need to look * for physical device (when called from ipv4) */ @@ -619,6 +631,7 @@ nfulnl_log_packet(u_int8_t pf, size += nla_total_size(data_len); break; + case NFULNL_COPY_DISABLED: default: goto unlock_and_release; } @@ -672,7 +685,7 @@ nfulnl_rcv_nl_event(struct notifier_block *this, int i; /* destroy all instances for this pid */ - write_lock_bh(&instances_lock); + spin_lock_bh(&instances_lock); for (i = 0; i < INSTANCE_BUCKETS; i++) { struct hlist_node *tmp, *t2; struct nfulnl_instance *inst; @@ -684,7 +697,7 @@ nfulnl_rcv_nl_event(struct notifier_block *this, __instance_destroy(inst); } } - write_unlock_bh(&instances_lock); + spin_unlock_bh(&instances_lock); } return NOTIFY_DONE; } @@ -861,19 +874,19 @@ static struct hlist_node *get_first(struct iter_state *st) for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) { if (!hlist_empty(&instance_table[st->bucket])) - return instance_table[st->bucket].first; + return rcu_dereference_bh(instance_table[st->bucket].first); } return NULL; } static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h) { - h = h->next; + h = rcu_dereference_bh(h->next); while (!h) { if (++st->bucket >= INSTANCE_BUCKETS) return NULL; - h = instance_table[st->bucket].first; + h = rcu_dereference_bh(instance_table[st->bucket].first); } return h; } @@ -890,9 +903,9 @@ static struct hlist_node *get_idx(struct iter_state *st, loff_t pos) } static void *seq_start(struct seq_file *seq, loff_t *pos) - __acquires(instances_lock) + __acquires(rcu_bh) { - read_lock_bh(&instances_lock); + rcu_read_lock_bh(); return get_idx(seq->private, *pos); } @@ -903,9 +916,9 @@ static void *seq_next(struct seq_file *s, void *v, loff_t *pos) } static void seq_stop(struct seq_file *s, void *v) - __releases(instances_lock) + __releases(rcu_bh) { - read_unlock_bh(&instances_lock); + rcu_read_unlock_bh(); } static int seq_show(struct seq_file *s, void *v) |