[NETFILTER]: nfnetlink_queue: remove useless enqueue status codes

[GitHub/exynos8895/android_kernel_samsung_universal8895.git] / net / netfilter / nfnetlink_queue.c

/*
 * This is a module which is used for queueing packets and communicating with
 * userspace via nfetlink.
 *
 * (C) 2005 by Harald Welte <laforge@netfilter.org>
 *
 * Based on the old ipv4-only ip_queue.c:
 * (C) 2000-2002 James Morris <jmorris@intercode.com.au>
 * (C) 2003-2005 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#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>
#include <linux/netfilter/nfnetlink_queue.h>
#include <linux/list.h>
#include <net/sock.h>
#include <net/netfilter/nf_queue.h>

#include <asm/atomic.h>

#ifdef CONFIG_BRIDGE_NETFILTER
#include "../bridge/br_private.h"
#endif

#define NFQNL_QMAX_DEFAULT 1024

struct nfqnl_instance {
        struct hlist_node hlist;                /* global list of queues */
        struct rcu_head rcu;

        int peer_pid;
        unsigned int queue_maxlen;
        unsigned int copy_range;
        unsigned int queue_total;
        unsigned int queue_dropped;
        unsigned int queue_user_dropped;

        unsigned int id_sequence;               /* 'sequence' of pkt ids */

        u_int16_t queue_num;                    /* number of this queue */
        u_int8_t copy_mode;

        spinlock_t lock;

        struct list_head queue_list;            /* packets in queue */
};

typedef int (*nfqnl_cmpfn)(struct nf_queue_entry *, unsigned long);

static DEFINE_SPINLOCK(instances_lock);

#define INSTANCE_BUCKETS        16
static struct hlist_head instance_table[INSTANCE_BUCKETS] __read_mostly;

static inline u_int8_t instance_hashfn(u_int16_t queue_num)
{
        return ((queue_num >> 8) | queue_num) % INSTANCE_BUCKETS;
}

static struct nfqnl_instance *
instance_lookup(u_int16_t queue_num)
{
        struct hlist_head *head;
        struct hlist_node *pos;
        struct nfqnl_instance *inst;

        head = &instance_table[instance_hashfn(queue_num)];
        hlist_for_each_entry_rcu(inst, pos, head, hlist) {
                if (inst->queue_num == queue_num)
                        return inst;
        }
        return NULL;
}

static struct nfqnl_instance *
instance_create(u_int16_t queue_num, int pid)
{
        struct nfqnl_instance *inst = NULL;
        unsigned int h;

        spin_lock(&instances_lock);
        if (instance_lookup(queue_num))
                goto out_unlock;

        inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
        if (!inst)
                goto out_unlock;

        inst->queue_num = queue_num;
        inst->peer_pid = pid;
        inst->queue_maxlen = NFQNL_QMAX_DEFAULT;
        inst->copy_range = 0xfffff;
        inst->copy_mode = NFQNL_COPY_NONE;
        spin_lock_init(&inst->lock);
        INIT_LIST_HEAD(&inst->queue_list);
        INIT_RCU_HEAD(&inst->rcu);

        if (!try_module_get(THIS_MODULE))
                goto out_free;

        h = instance_hashfn(queue_num);
        hlist_add_head_rcu(&inst->hlist, &instance_table[h]);

        spin_unlock(&instances_lock);

        return inst;

out_free:
        kfree(inst);
out_unlock:
        spin_unlock(&instances_lock);
        return NULL;
}

static void nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn,
                        unsigned long data);

static void
instance_destroy_rcu(struct rcu_head *head)
{
        struct nfqnl_instance *inst = container_of(head, struct nfqnl_instance,
                                                   rcu);

        nfqnl_flush(inst, NULL, 0);
        kfree(inst);
        module_put(THIS_MODULE);
}

static void
__instance_destroy(struct nfqnl_instance *inst)
{
        hlist_del_rcu(&inst->hlist);
        call_rcu(&inst->rcu, instance_destroy_rcu);
}

static void
instance_destroy(struct nfqnl_instance *inst)
{
        spin_lock(&instances_lock);
        __instance_destroy(inst);
        spin_unlock(&instances_lock);
}

static inline void
__enqueue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry)
{
       list_add_tail(&entry->list, &queue->queue_list);
       queue->queue_total++;
}

static struct nf_queue_entry *
find_dequeue_entry(struct nfqnl_instance *queue, unsigned int id)
{
        struct nf_queue_entry *entry = NULL, *i;

        spin_lock_bh(&queue->lock);

        list_for_each_entry(i, &queue->queue_list, list) {
                if (i->id == id) {
                        entry = i;
                        break;
                }
        }

        if (entry) {
                list_del(&entry->list);
                queue->queue_total--;
        }

        spin_unlock_bh(&queue->lock);

        return entry;
}

static void
nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn, unsigned long data)
{
        struct nf_queue_entry *entry, *next;

        spin_lock_bh(&queue->lock);
        list_for_each_entry_safe(entry, next, &queue->queue_list, list) {
                if (!cmpfn || cmpfn(entry, data)) {
                        list_del(&entry->list);
                        queue->queue_total--;
                        nf_reinject(entry, NF_DROP);
                }
        }
        spin_unlock_bh(&queue->lock);
}

static struct sk_buff *
nfqnl_build_packet_message(struct nfqnl_instance *queue,
                           struct nf_queue_entry *entry)
{
        sk_buff_data_t old_tail;
        size_t size;
        size_t data_len = 0;
        struct sk_buff *skb;
        struct nfqnl_msg_packet_hdr pmsg;
        struct nlmsghdr *nlh;
        struct nfgenmsg *nfmsg;
        struct sk_buff *entskb = entry->skb;
        struct net_device *indev;
        struct net_device *outdev;

        size =    NLMSG_ALIGN(sizeof(struct nfgenmsg))
                + nla_total_size(sizeof(struct nfqnl_msg_packet_hdr))
                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
#ifdef CONFIG_BRIDGE_NETFILTER
                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
#endif
                + nla_total_size(sizeof(u_int32_t))     /* mark */
                + nla_total_size(sizeof(struct nfqnl_msg_packet_hw))
                + nla_total_size(sizeof(struct nfqnl_msg_packet_timestamp));

        outdev = entry->outdev;

        spin_lock_bh(&queue->lock);

        switch ((enum nfqnl_config_mode)queue->copy_mode) {
        case NFQNL_COPY_META:
        case NFQNL_COPY_NONE:
                data_len = 0;
                break;

        case NFQNL_COPY_PACKET:
                if ((entskb->ip_summed == CHECKSUM_PARTIAL ||
                     entskb->ip_summed == CHECKSUM_COMPLETE) &&
                    skb_checksum_help(entskb)) {
                        spin_unlock_bh(&queue->lock);
                        return NULL;
                }
                if (queue->copy_range == 0
                    || queue->copy_range > entskb->len)
                        data_len = entskb->len;
                else
                        data_len = queue->copy_range;

                size += nla_total_size(data_len);
                break;
        }

        entry->id = queue->id_sequence++;

        spin_unlock_bh(&queue->lock);

        skb = alloc_skb(size, GFP_ATOMIC);
        if (!skb)
                goto nlmsg_failure;

        old_tail = skb->tail;
        nlh = NLMSG_PUT(skb, 0, 0,
                        NFNL_SUBSYS_QUEUE << 8 | NFQNL_MSG_PACKET,
                        sizeof(struct nfgenmsg));
        nfmsg = NLMSG_DATA(nlh);
        nfmsg->nfgen_family = entry->pf;
        nfmsg->version = NFNETLINK_V0;
        nfmsg->res_id = htons(queue->queue_num);

        pmsg.packet_id          = htonl(entry->id);
        pmsg.hw_protocol        = entskb->protocol;
        pmsg.hook               = entry->hook;

        NLA_PUT(skb, NFQA_PACKET_HDR, sizeof(pmsg), &pmsg);

        indev = entry->indev;
        if (indev) {
#ifndef CONFIG_BRIDGE_NETFILTER
                NLA_PUT_BE32(skb, NFQA_IFINDEX_INDEV, htonl(indev->ifindex));
#else
                if (entry->pf == PF_BRIDGE) {
                        /* Case 1: indev is physical input device, we need to
                         * look for bridge group (when called from
                         * netfilter_bridge) */
                        NLA_PUT_BE32(skb, NFQA_IFINDEX_PHYSINDEV,
                                     htonl(indev->ifindex));
                        /* this is the bridge group "brX" */
                        NLA_PUT_BE32(skb, NFQA_IFINDEX_INDEV,
                                     htonl(indev->br_port->br->dev->ifindex));
                } else {
                        /* Case 2: indev is bridge group, we need to look for
                         * physical device (when called from ipv4) */
                        NLA_PUT_BE32(skb, NFQA_IFINDEX_INDEV,
                                     htonl(indev->ifindex));
                        if (entskb->nf_bridge && entskb->nf_bridge->physindev)
                                NLA_PUT_BE32(skb, NFQA_IFINDEX_PHYSINDEV,
                                             htonl(entskb->nf_bridge->physindev->ifindex));
                }
#endif
        }

        if (outdev) {
#ifndef CONFIG_BRIDGE_NETFILTER
                NLA_PUT_BE32(skb, NFQA_IFINDEX_OUTDEV, htonl(outdev->ifindex));
#else
                if (entry->pf == PF_BRIDGE) {
                        /* Case 1: outdev is physical output device, we need to
                         * look for bridge group (when called from
                         * netfilter_bridge) */
                        NLA_PUT_BE32(skb, NFQA_IFINDEX_PHYSOUTDEV,
                                     htonl(outdev->ifindex));
                        /* this is the bridge group "brX" */
                        NLA_PUT_BE32(skb, NFQA_IFINDEX_OUTDEV,
                                     htonl(outdev->br_port->br->dev->ifindex));
                } else {
                        /* Case 2: outdev is bridge group, we need to look for
                         * physical output device (when called from ipv4) */
                        NLA_PUT_BE32(skb, NFQA_IFINDEX_OUTDEV,
                                     htonl(outdev->ifindex));
                        if (entskb->nf_bridge && entskb->nf_bridge->physoutdev)
                                NLA_PUT_BE32(skb, NFQA_IFINDEX_PHYSOUTDEV,
                                             htonl(entskb->nf_bridge->physoutdev->ifindex));
                }
#endif
        }

        if (entskb->mark)
                NLA_PUT_BE32(skb, NFQA_MARK, htonl(entskb->mark));

        if (indev && entskb->dev) {
                struct nfqnl_msg_packet_hw phw;
                int len = dev_parse_header(entskb, phw.hw_addr);
                if (len) {
                        phw.hw_addrlen = htons(len);
                        NLA_PUT(skb, NFQA_HWADDR, sizeof(phw), &phw);
                }
        }

        if (entskb->tstamp.tv64) {
                struct nfqnl_msg_packet_timestamp ts;
                struct timeval tv = ktime_to_timeval(entskb->tstamp);
                ts.sec = cpu_to_be64(tv.tv_sec);
                ts.usec = cpu_to_be64(tv.tv_usec);

                NLA_PUT(skb, NFQA_TIMESTAMP, sizeof(ts), &ts);
        }

        if (data_len) {
                struct nlattr *nla;
                int size = nla_attr_size(data_len);

                if (skb_tailroom(skb) < nla_total_size(data_len)) {
                        printk(KERN_WARNING "nf_queue: no tailroom!\n");
                        goto nlmsg_failure;
                }

                nla = (struct nlattr *)skb_put(skb, nla_total_size(data_len));
                nla->nla_type = NFQA_PAYLOAD;
                nla->nla_len = size;

                if (skb_copy_bits(entskb, 0, nla_data(nla), data_len))
                        BUG();
        }

        nlh->nlmsg_len = skb->tail - old_tail;
        return skb;

nlmsg_failure:
nla_put_failure:
        if (skb)
                kfree_skb(skb);
        if (net_ratelimit())
                printk(KERN_ERR "nf_queue: error creating packet message\n");
        return NULL;
}

static int
nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
{
        struct sk_buff *nskb;
        struct nfqnl_instance *queue;
        int err;

        /* rcu_read_lock()ed by nf_hook_slow() */
        queue = instance_lookup(queuenum);
        if (!queue)
                goto err_out;

        if (queue->copy_mode == NFQNL_COPY_NONE)
                goto err_out;

        nskb = nfqnl_build_packet_message(queue, entry);
        if (nskb == NULL)
                goto err_out;

        spin_lock_bh(&queue->lock);

        if (!queue->peer_pid)
                goto err_out_free_nskb;

        if (queue->queue_total >= queue->queue_maxlen) {
                queue->queue_dropped++;
                if (net_ratelimit())
                          printk(KERN_WARNING "nf_queue: full at %d entries, "
                                 "dropping packets(s). Dropped: %d\n",
                                 queue->queue_total, queue->queue_dropped);
                goto err_out_free_nskb;
        }

        /* nfnetlink_unicast will either free the nskb or add it to a socket */
        err = nfnetlink_unicast(nskb, queue->peer_pid, MSG_DONTWAIT);
        if (err < 0) {
                queue->queue_user_dropped++;
                goto err_out_unlock;
        }

        __enqueue_entry(queue, entry);

        spin_unlock_bh(&queue->lock);
        return 0;

err_out_free_nskb:
        kfree_skb(nskb);
err_out_unlock:
        spin_unlock_bh(&queue->lock);
err_out:
        return -1;
}

static int
nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e)
{
        int diff;
        int err;

        diff = data_len - e->skb->len;
        if (diff < 0) {
                if (pskb_trim(e->skb, data_len))
                        return -ENOMEM;
        } else if (diff > 0) {
                if (data_len > 0xFFFF)
                        return -EINVAL;
                if (diff > skb_tailroom(e->skb)) {
                        err = pskb_expand_head(e->skb, 0,
                                               diff - skb_tailroom(e->skb),
                                               GFP_ATOMIC);
                        if (err) {
                                printk(KERN_WARNING "nf_queue: OOM "
                                      "in mangle, dropping packet\n");
                                return err;
                        }
                }
                skb_put(e->skb, diff);
        }
        if (!skb_make_writable(e->skb, data_len))
                return -ENOMEM;
        skb_copy_to_linear_data(e->skb, data, data_len);
        e->skb->ip_summed = CHECKSUM_NONE;
        return 0;
}

static int
nfqnl_set_mode(struct nfqnl_instance *queue,
               unsigned char mode, unsigned int range)
{
        int status = 0;

        spin_lock_bh(&queue->lock);
        switch (mode) {
        case NFQNL_COPY_NONE:
        case NFQNL_COPY_META:
                queue->copy_mode = mode;
                queue->copy_range = 0;
                break;

        case NFQNL_COPY_PACKET:
                queue->copy_mode = mode;
                /* we're using struct nlattr which has 16bit nla_len */
                if (range > 0xffff)
                        queue->copy_range = 0xffff;
                else
                        queue->copy_range = range;
                break;

        default:
                status = -EINVAL;

        }
        spin_unlock_bh(&queue->lock);

        return status;
}

static int
dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex)
{
        if (entry->indev)
                if (entry->indev->ifindex == ifindex)
                        return 1;
        if (entry->outdev)
                if (entry->outdev->ifindex == ifindex)
                        return 1;
#ifdef CONFIG_BRIDGE_NETFILTER
        if (entry->skb->nf_bridge) {
                if (entry->skb->nf_bridge->physindev &&
                    entry->skb->nf_bridge->physindev->ifindex == ifindex)
                        return 1;
                if (entry->skb->nf_bridge->physoutdev &&
                    entry->skb->nf_bridge->physoutdev->ifindex == ifindex)
                        return 1;
        }
#endif
        return 0;
}

/* drop all packets with either indev or outdev == ifindex from all queue
 * instances */
static void
nfqnl_dev_drop(int ifindex)
{
        int i;

        rcu_read_lock();

        for (i = 0; i < INSTANCE_BUCKETS; i++) {
                struct hlist_node *tmp;
                struct nfqnl_instance *inst;
                struct hlist_head *head = &instance_table[i];

                hlist_for_each_entry_rcu(inst, tmp, head, hlist)
                        nfqnl_flush(inst, dev_cmp, ifindex);
        }

        rcu_read_unlock();
}

#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)

static int
nfqnl_rcv_dev_event(struct notifier_block *this,
                    unsigned long event, void *ptr)
{
        struct net_device *dev = ptr;

        if (dev->nd_net != &init_net)
                return NOTIFY_DONE;

        /* Drop any packets associated with the downed device */
        if (event == NETDEV_DOWN)
                nfqnl_dev_drop(dev->ifindex);
        return NOTIFY_DONE;
}

static struct notifier_block nfqnl_dev_notifier = {
        .notifier_call  = nfqnl_rcv_dev_event,
};

static int
nfqnl_rcv_nl_event(struct notifier_block *this,
                   unsigned long event, void *ptr)
{
        struct netlink_notify *n = ptr;

        if (event == NETLINK_URELEASE &&
            n->protocol == NETLINK_NETFILTER && n->pid) {
                int i;

                /* destroy all instances for this pid */
                spin_lock(&instances_lock);
                for (i = 0; i < INSTANCE_BUCKETS; i++) {
                        struct hlist_node *tmp, *t2;
                        struct nfqnl_instance *inst;
                        struct hlist_head *head = &instance_table[i];

                        hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
                                if ((n->net == &init_net) &&
                                    (n->pid == inst->peer_pid))
                                        __instance_destroy(inst);
                        }
                }
                spin_unlock(&instances_lock);
        }
        return NOTIFY_DONE;
}

static struct notifier_block nfqnl_rtnl_notifier = {
        .notifier_call  = nfqnl_rcv_nl_event,
};

static const struct nla_policy nfqa_verdict_policy[NFQA_MAX+1] = {
        [NFQA_VERDICT_HDR]      = { .len = sizeof(struct nfqnl_msg_verdict_hdr) },
        [NFQA_MARK]             = { .type = NLA_U32 },
        [NFQA_PAYLOAD]          = { .type = NLA_UNSPEC },
};

static int
nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
                   struct nlmsghdr *nlh, struct nlattr *nfqa[])
{
        struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
        u_int16_t queue_num = ntohs(nfmsg->res_id);

        struct nfqnl_msg_verdict_hdr *vhdr;
        struct nfqnl_instance *queue;
        unsigned int verdict;
        struct nf_queue_entry *entry;
        int err;

        rcu_read_lock();
        queue = instance_lookup(queue_num);
        if (!queue) {
                err = -ENODEV;
                goto err_out_unlock;
        }

        if (queue->peer_pid != NETLINK_CB(skb).pid) {
                err = -EPERM;
                goto err_out_unlock;
        }

        if (!nfqa[NFQA_VERDICT_HDR]) {
                err = -EINVAL;
                goto err_out_unlock;
        }

        vhdr = nla_data(nfqa[NFQA_VERDICT_HDR]);
        verdict = ntohl(vhdr->verdict);

        if ((verdict & NF_VERDICT_MASK) > NF_MAX_VERDICT) {
                err = -EINVAL;
                goto err_out_unlock;
        }

        entry = find_dequeue_entry(queue, ntohl(vhdr->id));
        if (entry == NULL) {
                err = -ENOENT;
                goto err_out_unlock;
        }
        rcu_read_unlock();

        if (nfqa[NFQA_PAYLOAD]) {
                if (nfqnl_mangle(nla_data(nfqa[NFQA_PAYLOAD]),
                                 nla_len(nfqa[NFQA_PAYLOAD]), entry) < 0)
                        verdict = NF_DROP;
        }

        if (nfqa[NFQA_MARK])
                entry->skb->mark = ntohl(nla_get_be32(nfqa[NFQA_MARK]));

        nf_reinject(entry, verdict);
        return 0;

err_out_unlock:
        rcu_read_unlock();
        return err;
}

static int
nfqnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
                  struct nlmsghdr *nlh, struct nlattr *nfqa[])
{
        return -ENOTSUPP;
}

static const struct nla_policy nfqa_cfg_policy[NFQA_CFG_MAX+1] = {
        [NFQA_CFG_CMD]          = { .len = sizeof(struct nfqnl_msg_config_cmd) },
        [NFQA_CFG_PARAMS]       = { .len = sizeof(struct nfqnl_msg_config_params) },
};

static const struct nf_queue_handler nfqh = {
        .name   = "nf_queue",
        .outfn  = &nfqnl_enqueue_packet,
};

static int
nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
                  struct nlmsghdr *nlh, struct nlattr *nfqa[])
{
        struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
        u_int16_t queue_num = ntohs(nfmsg->res_id);
        struct nfqnl_instance *queue;
        struct nfqnl_msg_config_cmd *cmd = NULL;
        int ret = 0;

        if (nfqa[NFQA_CFG_CMD]) {
                cmd = nla_data(nfqa[NFQA_CFG_CMD]);

                /* Commands without queue context - might sleep */
                switch (cmd->command) {
                case NFQNL_CFG_CMD_PF_BIND:
                        ret = nf_register_queue_handler(ntohs(cmd->pf),
                                                        &nfqh);
                        break;
                case NFQNL_CFG_CMD_PF_UNBIND:
                        ret = nf_unregister_queue_handler(ntohs(cmd->pf),
                                                          &nfqh);
                        break;
                default:
                        break;
                }

                if (ret < 0)
                        return ret;
        }

        rcu_read_lock();
        queue = instance_lookup(queue_num);
        if (queue && queue->peer_pid != NETLINK_CB(skb).pid) {
                ret = -EPERM;
                goto err_out_unlock;
        }

        if (cmd != NULL) {
                switch (cmd->command) {
                case NFQNL_CFG_CMD_BIND:
                        if (queue) {
                                ret = -EBUSY;
                                goto err_out_unlock;
                        }
                        queue = instance_create(queue_num, NETLINK_CB(skb).pid);
                        if (!queue) {
                                ret = -EINVAL;
                                goto err_out_unlock;
                        }
                        break;
                case NFQNL_CFG_CMD_UNBIND:
                        if (!queue) {
                                ret = -ENODEV;
                                goto err_out_unlock;
                        }
                        instance_destroy(queue);
                        break;
                case NFQNL_CFG_CMD_PF_BIND:
                case NFQNL_CFG_CMD_PF_UNBIND:
                        break;
                default:
                        ret = -EINVAL;
                        break;
                }
        }

        if (nfqa[NFQA_CFG_PARAMS]) {
                struct nfqnl_msg_config_params *params;

                if (!queue) {
                        ret = -ENODEV;
                        goto err_out_unlock;
                }
                params = nla_data(nfqa[NFQA_CFG_PARAMS]);
                nfqnl_set_mode(queue, params->copy_mode,
                                ntohl(params->copy_range));
        }

        if (nfqa[NFQA_CFG_QUEUE_MAXLEN]) {
                __be32 *queue_maxlen;

                if (!queue) {
                        ret = -ENODEV;
                        goto err_out_unlock;
                }
                queue_maxlen = nla_data(nfqa[NFQA_CFG_QUEUE_MAXLEN]);
                spin_lock_bh(&queue->lock);
                queue->queue_maxlen = ntohl(*queue_maxlen);
                spin_unlock_bh(&queue->lock);
        }

err_out_unlock:
        rcu_read_unlock();
        return ret;
}

static const struct nfnl_callback nfqnl_cb[NFQNL_MSG_MAX] = {
        [NFQNL_MSG_PACKET]      = { .call = nfqnl_recv_unsupp,
                                    .attr_count = NFQA_MAX, },
        [NFQNL_MSG_VERDICT]     = { .call = nfqnl_recv_verdict,
                                    .attr_count = NFQA_MAX,
                                    .policy = nfqa_verdict_policy },
        [NFQNL_MSG_CONFIG]      = { .call = nfqnl_recv_config,
                                    .attr_count = NFQA_CFG_MAX,
                                    .policy = nfqa_cfg_policy },
};

static const struct nfnetlink_subsystem nfqnl_subsys = {
        .name           = "nf_queue",
        .subsys_id      = NFNL_SUBSYS_QUEUE,
        .cb_count       = NFQNL_MSG_MAX,
        .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)
{
        spin_lock(&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)
{
        spin_unlock(&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,
                          inst->id_sequence, 1);
}

static const 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)
{
        return seq_open_private(file, &nfqnl_seq_ops,
                        sizeof(struct iter_state));
}

static const 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 nfnetlink_queue_init(void)
{
        int i, status = -ENOMEM;
#ifdef CONFIG_PROC_FS
        struct proc_dir_entry *proc_nfqueue;
#endif

        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) {
                printk(KERN_ERR "nf_queue: failed to create netlink socket\n");
                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;

#ifdef CONFIG_PROC_FS
cleanup_subsys:
        nfnetlink_subsys_unregister(&nfqnl_subsys);
#endif
cleanup_netlink_notifier:
        netlink_unregister_notifier(&nfqnl_rtnl_notifier);
        return status;
}

static void __exit nfnetlink_queue_fini(void)
{
        nf_unregister_queue_handlers(&nfqh);
        unregister_netdevice_notifier(&nfqnl_dev_notifier);
#ifdef CONFIG_PROC_FS
        remove_proc_entry("nfnetlink_queue", proc_net_netfilter);
#endif
        nfnetlink_subsys_unregister(&nfqnl_subsys);
        netlink_unregister_notifier(&nfqnl_rtnl_notifier);
}

MODULE_DESCRIPTION("netfilter packet queue handler");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_QUEUE);

module_init(nfnetlink_queue_init);
module_exit(nfnetlink_queue_fini);