[NETFILTER]: Add refcounting and /proc/net/netfilter interface to nfnetlink_queue

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 221 insertions, 28 deletions

diff --git a/include/linux/netfilter/nfnetlink_queue.h b/include/linux/netfilter/nfnetlink_queue.h
index edb463a87eb4..e142b0ff7c08 100644
--- a/include/linux/netfilter/nfnetlink_queue.h
+++ b/include/linux/netfilter/nfnetlink_queue.h
@@ -81,5 +81,6 @@ enum nfqnl_attr_config {
         NFQA_CFG_PARAMS,                /* nfqnl_msg_config_params */
         __NFQA_CFG_MAX
 };
+#define NFQA_CFG_MAX (__NFQA_CFG_MAX-1)
 
 #endif /* _NFNETLINK_QUEUE_H */
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 24032610c425..eab309e3d42e 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -20,6 +20,7 @@
 #include <linux/notifier.h>
 #include <linux/netdevice.h>
 #include <linux/netfilter.h>
+#include <linux/proc_fs.h>
 #include <linux/netfilter_ipv4.h>
 #include <linux/netfilter_ipv6.h>
 #include <linux/netfilter/nfnetlink.h>
@@ -48,6 +49,7 @@ struct nfqnl_queue_entry {
 
 struct nfqnl_instance {
         struct hlist_node hlist;                /* global list of queues */
+        atomic_t use;
 
         int peer_pid;
         unsigned int queue_maxlen;
@@ -105,17 +107,28 @@ __instance_lookup(u_int16_t queue_num)
 }
 
 static struct nfqnl_instance *
-instance_lookup(u_int16_t queue_num)
+instance_lookup_get(u_int16_t queue_num)
 {
         struct nfqnl_instance *inst;
 
         read_lock_bh(&instances_lock);
         inst = __instance_lookup(queue_num);
+        if (inst)
+                atomic_inc(&inst->use);
         read_unlock_bh(&instances_lock);
 
         return inst;
 }
 
+static void
+instance_put(struct nfqnl_instance *inst)
+{
+        if (inst && atomic_dec_and_test(&inst->use)) {
+                QDEBUG("kfree(inst=%p)\n", inst);
+                kfree(inst);
+        }
+}
+
 static struct nfqnl_instance *
 instance_create(u_int16_t queue_num, int pid)
 {
@@ -141,6 +154,8 @@ instance_create(u_int16_t queue_num, int pid)
         inst->copy_range = 0xfffff;
         inst->copy_mode = NFQNL_COPY_NONE;
         atomic_set(&inst->id_sequence, 0);
+        /* needs to be two, since we _put() after creation */
+        atomic_set(&inst->use, 2);
         inst->lock = SPIN_LOCK_UNLOCKED;
         INIT_LIST_HEAD(&inst->queue_list);
 
@@ -182,8 +197,8 @@ _instance_destroy2(struct nfqnl_instance *inst, int lock)
         /* then flush all pending skbs from the queue */
         nfqnl_flush(inst, NF_DROP);
 
-        /* and finally free the data structure */
-        kfree(inst);
+        /* and finally put the refcount */
+        instance_put(inst);
 
         module_put(THIS_MODULE);
 }
@@ -471,7 +486,7 @@ nfqnl_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
 
         QDEBUG("entered\n");
 
-        queue = instance_lookup(queuenum);
+        queue = instance_lookup_get(queuenum);
         if (!queue) {
                 QDEBUG("no queue instance matching\n");
                 return -EINVAL;
@@ -479,7 +494,8 @@ nfqnl_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
 
         if (queue->copy_mode == NFQNL_COPY_NONE) {
                 QDEBUG("mode COPY_NONE, aborting\n");
-                return -EAGAIN;
+                status = -EAGAIN;
+                goto err_out_put;
         }
 
         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
@@ -487,7 +503,8 @@ nfqnl_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
                 if (net_ratelimit())
                         printk(KERN_ERR 
                                 "nf_queue: OOM in nfqnl_enqueue_packet()\n");
-                return -ENOMEM;
+                status = -ENOMEM;
+                goto err_out_put;
         }
 
         entry->info = info;
@@ -523,6 +540,7 @@ nfqnl_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
         __enqueue_entry(queue, entry);
 
         spin_unlock_bh(&queue->lock);
+        instance_put(queue);
         return status;
 
 err_out_free_nskb:
@@ -533,6 +551,8 @@ err_out_unlock:
 
 err_out_free:
         kfree(entry);
+err_out_put:
+        instance_put(queue);
         return status;
 }
 
@@ -685,6 +705,12 @@ static struct notifier_block nfqnl_rtnl_notifier = {
         .notifier_call  = nfqnl_rcv_nl_event,
 };
 
+static const int nfqa_verdict_min[NFQA_MAX] = {
+        [NFQA_VERDICT_HDR-1]    = sizeof(struct nfqnl_msg_verdict_hdr),
+        [NFQA_MARK-1]           = sizeof(u_int32_t),
+        [NFQA_PAYLOAD-1]        = 0,
+};
+
 static int
 nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
                    struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
@@ -696,26 +722,40 @@ nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
         struct nfqnl_instance *queue;
         unsigned int verdict;
         struct nfqnl_queue_entry *entry;
+        int err;
 
-        queue = instance_lookup(queue_num);
+        if (nfattr_bad_size(nfqa, NFQA_MAX, nfqa_verdict_min)) {
+                QDEBUG("bad attribute size\n");
+                return -EINVAL;
+        }
+
+        queue = instance_lookup_get(queue_num);
         if (!queue)
                 return -ENODEV;
 
-        if (queue->peer_pid != NETLINK_CB(skb).pid)
-                return -EPERM;
+        if (queue->peer_pid != NETLINK_CB(skb).pid) {
+                err = -EPERM;
+                goto err_out_put;
+        }
 
-        if (!nfqa[NFQA_VERDICT_HDR-1])
-                return -EINVAL;
+        if (!nfqa[NFQA_VERDICT_HDR-1]) {
+                err = -EINVAL;
+                goto err_out_put;
+        }
 
         vhdr = NFA_DATA(nfqa[NFQA_VERDICT_HDR-1]);
         verdict = ntohl(vhdr->verdict);
 
-        if ((verdict & NF_VERDICT_MASK) > NF_MAX_VERDICT)
-                return -EINVAL;
+        if ((verdict & NF_VERDICT_MASK) > NF_MAX_VERDICT) {
+                err = -EINVAL;
+                goto err_out_put;
+        }
 
         entry = find_dequeue_entry(queue, id_cmp, ntohl(vhdr->id));
-        if (entry == NULL)
-                return -ENOENT;
+        if (entry == NULL) {
+                err = -ENOENT;
+                goto err_out_put;
+        }
 
         if (nfqa[NFQA_PAYLOAD-1]) {
                 if (nfqnl_mangle(NFA_DATA(nfqa[NFQA_PAYLOAD-1]),
@@ -727,7 +767,12 @@ nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
                 skb->nfmark = ntohl(*(u_int32_t *)NFA_DATA(nfqa[NFQA_MARK-1]));
                 
         issue_verdict(entry, verdict);
+        instance_put(queue);
         return 0;
+
+err_out_put:
+        instance_put(queue);
+        return err;
 }
 
 static int
@@ -737,6 +782,11 @@ nfqnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
         return -ENOTSUPP;
 }
 
+static const int nfqa_cfg_min[NFQA_CFG_MAX] = {
+        [NFQA_CFG_CMD-1]        = sizeof(struct nfqnl_msg_config_cmd),
+        [NFQA_CFG_PARAMS-1]     = sizeof(struct nfqnl_msg_config_params),
+};
+
 static int
 nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
                   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
@@ -744,10 +794,16 @@ nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
         u_int16_t queue_num = ntohs(nfmsg->res_id);
         struct nfqnl_instance *queue;
+        int ret = 0;
 
         QDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
 
-        queue = instance_lookup(queue_num);
+        if (nfattr_bad_size(nfqa, NFQA_CFG_MAX, nfqa_cfg_min)) {
+                QDEBUG("bad attribute size\n");
+                return -EINVAL;
+        }
+
+        queue = instance_lookup_get(queue_num);
         if (nfqa[NFQA_CFG_CMD-1]) {
                 struct nfqnl_msg_config_cmd *cmd;
                 cmd = NFA_DATA(nfqa[NFQA_CFG_CMD-1]);
@@ -766,17 +822,19 @@ nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
                         if (!queue)
                                 return -ENODEV;
 
-                        if (queue->peer_pid != NETLINK_CB(skb).pid)
-                                return -EPERM;
+                        if (queue->peer_pid != NETLINK_CB(skb).pid) {
+                                ret = -EPERM;
+                                goto out_put;
+                        }
 
                         instance_destroy(queue);
                         break;
                 case NFQNL_CFG_CMD_PF_BIND:
                         QDEBUG("registering queue handler for pf=%u\n",
                                 ntohs(cmd->pf));
-                        return nf_register_queue_handler(ntohs(cmd->pf),
-                                                         nfqnl_enqueue_packet,
-                                                         NULL);
+                        ret = nf_register_queue_handler(ntohs(cmd->pf),
+                                                        nfqnl_enqueue_packet,
+                                                        NULL);
 
                         break;
                 case NFQNL_CFG_CMD_PF_UNBIND:
@@ -784,20 +842,23 @@ nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
                                 ntohs(cmd->pf));
                         /* This is a bug and a feature.  We can unregister
                          * other handlers(!) */
-                        return nf_unregister_queue_handler(ntohs(cmd->pf));
+                        ret = nf_unregister_queue_handler(ntohs(cmd->pf));
                         break;
                 default:
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        break;
                 }
         } else {
                 if (!queue) {
                         QDEBUG("no config command, and no instance ENOENT\n");
-                        return -ENOENT;
+                        ret = -ENOENT;
+                        goto out_put;
                 }
 
                 if (queue->peer_pid != NETLINK_CB(skb).pid) {
                         QDEBUG("no config command, and wrong pid\n");
-                        return -EPERM;
+                        ret = -EPERM;
+                        goto out_put;
                 }
         }
 
@@ -809,7 +870,9 @@ nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
                                 ntohl(params->copy_range));
         }
 
-        return 0;
+out_put:
+        instance_put(queue);
+        return ret;
 }
 
 static struct nfnl_callback nfqnl_cb[NFQNL_MSG_MAX] = {
@@ -829,14 +892,132 @@ static struct nfnetlink_subsystem nfqnl_subsys = {
         .cb             = nfqnl_cb,
 };
 
+#ifdef CONFIG_PROC_FS
+struct iter_state {
+        unsigned int bucket;
+};
+
+static struct hlist_node *get_first(struct seq_file *seq)
+{
+        struct iter_state *st = seq->private;
+
+        if (!st)
+                return NULL;
+
+        for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
+                if (!hlist_empty(&instance_table[st->bucket]))
+                        return instance_table[st->bucket].first;
+        }
+        return NULL;
+}
+
+static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
+{
+        struct iter_state *st = seq->private;
+
+        h = h->next;
+        while (!h) {
+                if (++st->bucket >= INSTANCE_BUCKETS)
+                        return NULL;
+
+                h = instance_table[st->bucket].first;
+        }
+        return h;
+}
+
+static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
+{
+        struct hlist_node *head;
+        head = get_first(seq);
+
+        if (head)
+                while (pos && (head = get_next(seq, head)))
+                        pos--;
+        return pos ? NULL : head;
+}
+
+static void *seq_start(struct seq_file *seq, loff_t *pos)
+{
+        read_lock_bh(&instances_lock);
+        return get_idx(seq, *pos);
+}
+
+static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+        (*pos)++;
+        return get_next(s, v);
+}
+
+static void seq_stop(struct seq_file *s, void *v)
+{
+        read_unlock_bh(&instances_lock);
+}
+
+static int seq_show(struct seq_file *s, void *v)
+{
+        const struct nfqnl_instance *inst = v;
+
+        return seq_printf(s, "%5d %6d %5d %1d %5d %5d %5d %8d %2d\n",
+                          inst->queue_num,
+                          inst->peer_pid, inst->queue_total,
+                          inst->copy_mode, inst->copy_range,
+                          inst->queue_dropped, inst->queue_user_dropped,
+                          atomic_read(&inst->id_sequence),
+                          atomic_read(&inst->use));
+}
+
+static struct seq_operations nfqnl_seq_ops = {
+        .start  = seq_start,
+        .next   = seq_next,
+        .stop   = seq_stop,
+        .show   = seq_show,
+};
+
+static int nfqnl_open(struct inode *inode, struct file *file)
+{
+        struct seq_file *seq;
+        struct iter_state *is;
+        int ret;
+
+        is = kmalloc(sizeof(*is), GFP_KERNEL);
+        if (!is)
+                return -ENOMEM;
+        memset(is, 0, sizeof(*is));
+        ret = seq_open(file, &nfqnl_seq_ops);
+        if (ret < 0)
+                goto out_free;
+        seq = file->private_data;
+        seq->private = is;
+        return ret;
+out_free:
+        kfree(is);
+        return ret;
+}
+
+static struct file_operations nfqnl_file_ops = {
+        .owner   = THIS_MODULE,
+        .open    = nfqnl_open,
+        .read    = seq_read,
+        .llseek  = seq_lseek,
+        .release = seq_release_private,
+};
+
+#endif /* PROC_FS */
+
 static int
 init_or_cleanup(int init)
 {
-        int status = -ENOMEM;
+        int i, status = -ENOMEM;
+#ifdef CONFIG_PROC_FS
+        struct proc_dir_entry *proc_nfqueue;
+#endif
         
         if (!init)
                 goto cleanup;
 
+        for (i = 0; i < INSTANCE_BUCKETS; i++)
+                INIT_HLIST_HEAD(&instance_table[i]);
+
         netlink_register_notifier(&nfqnl_rtnl_notifier);
         status = nfnetlink_subsys_register(&nfqnl_subsys);
         if (status < 0) {
@@ -844,14 +1025,25 @@ init_or_cleanup(int init)
                 goto cleanup_netlink_notifier;
         }
 
+#ifdef CONFIG_PROC_FS
+        proc_nfqueue = create_proc_entry("nfnetlink_queue", 0440,
+                                         proc_net_netfilter);
+        if (!proc_nfqueue)
+                goto cleanup_subsys;
+        proc_nfqueue->proc_fops = &nfqnl_file_ops;
+#endif
+
         register_netdevice_notifier(&nfqnl_dev_notifier);
+
         return status;
 
 cleanup:
         nf_unregister_queue_handlers(nfqnl_enqueue_packet);
         unregister_netdevice_notifier(&nfqnl_dev_notifier);
+#ifdef CONFIG_PROC_FS
+cleanup_subsys:
+#endif  
         nfnetlink_subsys_unregister(&nfqnl_subsys);
-        
 cleanup_netlink_notifier:
         netlink_unregister_notifier(&nfqnl_rtnl_notifier);
         return status;