[NETFILTER]: Add refcounting and /proc/net/netfilter interface to nfnetlink_queue
authorHarald Welte <laforge@netfilter.org>
Wed, 10 Aug 2005 02:50:45 +0000 (19:50 -0700)
committerDavid S. Miller <davem@sunset.davemloft.net>
Mon, 29 Aug 2005 22:38:01 +0000 (15:38 -0700)
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/linux/netfilter/nfnetlink_queue.h
net/netfilter/nfnetlink_queue.c

index edb463a87eb4f36d748bdf6c4840ff222117e51f..e142b0ff7c08b6e1bb05939897b62e2fabfabbae 100644 (file)
@@ -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 */
index 24032610c4255ee0a9b79df8adc6f7b42808afd3..eab309e3d42ed2e36adc349bd2fedaf815ebc43d 100644 (file)
@@ -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;