// SPDX-License-Identifier: GPL-2.0-only
/*
 * This is a module which is used for queueing packets and communicating with
 * userspace via nfnetlink.
 *
 * (C) 2005 by Harald Welte <laforge@netfilter.org>
 * (C) 2007 by Patrick McHardy <kaber@trash.net>
 *
 * 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>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/slab.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_bridge.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_queue.h>
#include <linux/netfilter/nf_conntrack_common.h>
#include <linux/list.h>
#include <linux/cgroup-defs.h>
#include <linux/rhashtable.h>
#include <linux/jhash.h>
#include <net/gso.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/netfilter/nf_queue.h>
#include <net/netns/generic.h>

#include <linux/atomic.h>

#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
#include "../bridge/br_private.h"
#endif

#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#include <net/netfilter/nf_conntrack.h>
#endif

#define NFQNL_QMAX_DEFAULT 1024
#define NFQNL_HASH_MIN     1024
#define NFQNL_HASH_MAX     1048576

/* We're using struct nlattr which has 16bit nla_len. Note that nla_len
 * includes the header length. Thus, the maximum packet length that we
 * support is 65531 bytes. We send truncated packets if the specified length
 * is larger than that.  Userspace can check for presence of NFQA_CAP_LEN
 * attribute to detect truncation.
 */
#define NFQNL_MAX_COPY_RANGE (0xffff - NLA_HDRLEN)

/* Composite key for packet lookup: (net, queue_num, packet_id) */
struct nfqnl_packet_key {
        possible_net_t net;
        u32 packet_id;
        u16 queue_num;
} __aligned(sizeof(u32));  /* jhash2 requires 32-bit alignment */

/* Global rhashtable - one for entire system, all netns */
static struct rhashtable nfqnl_packet_map __read_mostly;

/* Helper to initialize composite key */
static inline void nfqnl_init_key(struct nfqnl_packet_key *key,
                                  struct net *net, u32 packet_id, u16 queue_num)
{
        memset(key, 0, sizeof(*key));
        write_pnet(&key->net, net);
        key->packet_id = packet_id;
        key->queue_num = queue_num;
}

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

        u32 peer_portid;
        unsigned int queue_maxlen;
        unsigned int copy_range;
        unsigned int queue_dropped;
        unsigned int queue_user_dropped;


        u_int16_t queue_num;                    /* number of this queue */
        u_int8_t copy_mode;
        u_int32_t flags;                        /* Set using NFQA_CFG_FLAGS */
/*
 * Following fields are dirtied for each queued packet,
 * keep them in same cache line if possible.
 */
        spinlock_t      lock    ____cacheline_aligned_in_smp;
        unsigned int    queue_total;
        unsigned int    id_sequence;            /* 'sequence' of pkt ids */
        struct list_head queue_list;            /* packets in queue */
};

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

static unsigned int nfnl_queue_net_id __read_mostly;

#define INSTANCE_BUCKETS        16
struct nfnl_queue_net {
        spinlock_t instances_lock;
        struct hlist_head instance_table[INSTANCE_BUCKETS];
};

static struct nfnl_queue_net *nfnl_queue_pernet(struct net *net)
{
        return net_generic(net, nfnl_queue_net_id);
}

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

/* Extract composite key from nf_queue_entry for hashing */
static u32 nfqnl_packet_obj_hashfn(const void *data, u32 len, u32 seed)
{
        const struct nf_queue_entry *entry = data;
        struct nfqnl_packet_key key;

        nfqnl_init_key(&key, entry->state.net, entry->id, entry->queue_num);

        return jhash2((u32 *)&key, sizeof(key) / sizeof(u32), seed);
}

/* Compare stack-allocated key against entry */
static int nfqnl_packet_obj_cmpfn(struct rhashtable_compare_arg *arg,
                                  const void *obj)
{
        const struct nfqnl_packet_key *key = arg->key;
        const struct nf_queue_entry *entry = obj;

        return !net_eq(entry->state.net, read_pnet(&key->net)) ||
               entry->queue_num != key->queue_num ||
               entry->id != key->packet_id;
}

static const struct rhashtable_params nfqnl_rhashtable_params = {
        .head_offset = offsetof(struct nf_queue_entry, hash_node),
        .key_len = sizeof(struct nfqnl_packet_key),
        .obj_hashfn = nfqnl_packet_obj_hashfn,
        .obj_cmpfn = nfqnl_packet_obj_cmpfn,
        .automatic_shrinking = true,
        .min_size = NFQNL_HASH_MIN,
        .max_size = NFQNL_HASH_MAX,
};

static struct nfqnl_instance *
instance_lookup(struct nfnl_queue_net *q, u_int16_t queue_num)
{
        struct hlist_head *head;
        struct nfqnl_instance *inst;

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

static struct nfqnl_instance *
instance_create(struct nfnl_queue_net *q, u_int16_t queue_num, u32 portid)
{
        struct nfqnl_instance *inst;
        unsigned int h;
        int err;

        inst = kzalloc_obj(*inst, GFP_KERNEL_ACCOUNT);
        if (!inst)
                return ERR_PTR(-ENOMEM);

        inst->queue_num = queue_num;
        inst->peer_portid = portid;
        inst->queue_maxlen = NFQNL_QMAX_DEFAULT;
        inst->copy_range = NFQNL_MAX_COPY_RANGE;
        inst->copy_mode = NFQNL_COPY_NONE;
        spin_lock_init(&inst->lock);
        INIT_LIST_HEAD(&inst->queue_list);

        spin_lock(&q->instances_lock);
        if (instance_lookup(q, queue_num)) {
                err = -EEXIST;
                goto out_unlock;
        }

        if (!try_module_get(THIS_MODULE)) {
                err = -EAGAIN;
                goto out_unlock;
        }

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

        spin_unlock(&q->instances_lock);

        return inst;

out_unlock:
        spin_unlock(&q->instances_lock);
        kfree(inst);
        return ERR_PTR(err);
}

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);

        rcu_read_lock();
        nfqnl_flush(inst, NULL, 0);
        rcu_read_unlock();
        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 nfnl_queue_net *q, struct nfqnl_instance *inst)
{
        spin_lock(&q->instances_lock);
        __instance_destroy(inst);
        spin_unlock(&q->instances_lock);
}

static int
__enqueue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry)
{
        int err;

        entry->queue_num = queue->queue_num;

        err = rhashtable_insert_fast(&nfqnl_packet_map, &entry->hash_node,
                                     nfqnl_rhashtable_params);
        if (unlikely(err))
                return err;

        list_add_tail(&entry->list, &queue->queue_list);
        queue->queue_total++;

        return 0;
}

static void
__dequeue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry)
{
        rhashtable_remove_fast(&nfqnl_packet_map, &entry->hash_node,
                               nfqnl_rhashtable_params);
        list_del(&entry->list);
        queue->queue_total--;
}

static struct nf_queue_entry *
find_dequeue_entry(struct nfqnl_instance *queue, unsigned int id,
                   struct net *net)
{
        struct nfqnl_packet_key key;
        struct nf_queue_entry *entry;

        nfqnl_init_key(&key, net, id, queue->queue_num);

        spin_lock_bh(&queue->lock);
        entry = rhashtable_lookup_fast(&nfqnl_packet_map, &key,
                                       nfqnl_rhashtable_params);

        if (entry)
                __dequeue_entry(queue, entry);

        spin_unlock_bh(&queue->lock);

        return entry;
}

static unsigned int nf_iterate(struct sk_buff *skb,
                               struct nf_hook_state *state,
                               const struct nf_hook_entries *hooks,
                               unsigned int *index)
{
        const struct nf_hook_entry *hook;
        unsigned int verdict, i = *index;

        while (i < hooks->num_hook_entries) {
                hook = &hooks->hooks[i];
repeat:
                verdict = nf_hook_entry_hookfn(hook, skb, state);
                if (verdict != NF_ACCEPT) {
                        *index = i;
                        if (verdict != NF_REPEAT)
                                return verdict;
                        goto repeat;
                }
                i++;
        }

        *index = i;
        return NF_ACCEPT;
}

static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
{
        switch (pf) {
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
        case NFPROTO_BRIDGE:
                return rcu_dereference(net->nf.hooks_bridge[hooknum]);
#endif
        case NFPROTO_IPV4:
                return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
        case NFPROTO_IPV6:
                return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
        default:
                WARN_ON_ONCE(1);
                return NULL;
        }

        return NULL;
}

static int nf_ip_reroute(struct sk_buff *skb, const struct nf_queue_entry *entry)
{
#ifdef CONFIG_INET
        const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);

        if (entry->state.hook == NF_INET_LOCAL_OUT) {
                const struct iphdr *iph = ip_hdr(skb);

                if (!(iph->tos == rt_info->tos &&
                      skb->mark == rt_info->mark &&
                      iph->daddr == rt_info->daddr &&
                      iph->saddr == rt_info->saddr))
                        return ip_route_me_harder(entry->state.net, entry->state.sk,
                                                  skb, RTN_UNSPEC);
        }
#endif
        return 0;
}

static int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry)
{
        const struct nf_ipv6_ops *v6ops;
        int ret = 0;

        switch (entry->state.pf) {
        case AF_INET:
                ret = nf_ip_reroute(skb, entry);
                break;
        case AF_INET6:
                v6ops = rcu_dereference(nf_ipv6_ops);
                if (v6ops)
                        ret = v6ops->reroute(skb, entry);
                break;
        }
        return ret;
}

/* caller must hold rcu read-side lock */
static void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
{
        const struct nf_hook_entry *hook_entry;
        const struct nf_hook_entries *hooks;
        struct sk_buff *skb = entry->skb;
        const struct net *net;
        unsigned int i;
        int err;
        u8 pf;

        net = entry->state.net;
        pf = entry->state.pf;

        hooks = nf_hook_entries_head(net, pf, entry->state.hook);

        i = entry->hook_index;
        if (!hooks || i >= hooks->num_hook_entries) {
                kfree_skb_reason(skb, SKB_DROP_REASON_NETFILTER_DROP);
                nf_queue_entry_free(entry);
                return;
        }

        hook_entry = &hooks->hooks[i];

        /* Continue traversal iff userspace said ok... */
        if (verdict == NF_REPEAT)
                verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);

        if (verdict == NF_ACCEPT) {
                if (nf_reroute(skb, entry) < 0)
                        verdict = NF_DROP;
        }

        if (verdict == NF_ACCEPT) {
next_hook:
                ++i;
                verdict = nf_iterate(skb, &entry->state, hooks, &i);
        }

        switch (verdict & NF_VERDICT_MASK) {
        case NF_ACCEPT:
        case NF_STOP:
                local_bh_disable();
                entry->state.okfn(entry->state.net, entry->state.sk, skb);
                local_bh_enable();
                break;
        case NF_QUEUE:
                err = nf_queue(skb, &entry->state, i, verdict);
                if (err == 1)
                        goto next_hook;
                break;
        case NF_STOLEN:
                break;
        default:
                kfree_skb(skb);
        }

        nf_queue_entry_free(entry);
}

/* return true if the entry has an unconfirmed conntrack attached that isn't owned by us
 * exclusively.
 */
static bool nf_ct_drop_unconfirmed(const struct nf_queue_entry *entry, bool *is_unconfirmed)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
        struct nf_conn *ct = (void *)skb_nfct(entry->skb);

        if (!ct || nf_ct_is_confirmed(ct))
                return false;

        if (is_unconfirmed)
                *is_unconfirmed = true;

        /* in some cases skb_clone() can occur after initial conntrack
         * pickup, but conntrack assumes exclusive skb->_nfct ownership for
         * unconfirmed entries.
         *
         * This happens for br_netfilter and with ip multicast routing.
         * This can't be solved with serialization here because one clone
         * could have been queued for local delivery or could be transmitted
         * in parallel on another CPU.
         */
        return refcount_read(&ct->ct_general.use) > 1;
#endif
        return false;
}

static void nfqnl_reinject(struct nf_queue_entry *entry, unsigned int verdict)
{
        const struct nf_ct_hook *ct_hook;

        if (verdict == NF_ACCEPT ||
            verdict == NF_REPEAT ||
            verdict == NF_STOP) {
                unsigned int ct_verdict = verdict;

                rcu_read_lock();
                ct_hook = rcu_dereference(nf_ct_hook);
                if (ct_hook)
                        ct_verdict = ct_hook->update(entry->state.net, entry->skb);
                rcu_read_unlock();

                switch (ct_verdict & NF_VERDICT_MASK) {
                case NF_ACCEPT:
                        /* follow userspace verdict, could be REPEAT */
                        break;
                case NF_STOLEN:
                        nf_queue_entry_free(entry);
                        return;
                default:
                        verdict = ct_verdict & NF_VERDICT_MASK;
                        break;
                }
        }

        if (verdict != NF_DROP && entry->nf_ct_is_unconfirmed) {
                /* If first queued segment was already reinjected then
                 * there is a good chance the ct entry is now confirmed.
                 *
                 * Handle the rare cases:
                 *  - out-of-order verdict
                 *  - threaded userspace reinjecting in parallel
                 *  - first segment was dropped
                 *
                 * In all of those cases we can't handle this packet
                 * because we can't be sure that another CPU won't modify
                 * nf_conn->ext in parallel which isn't allowed.
                 */
                if (nf_ct_drop_unconfirmed(entry, NULL))
                        verdict = NF_DROP;
        }

        nf_reinject(entry, verdict);
}

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)) {
                        __dequeue_entry(queue, entry);
                        nfqnl_reinject(entry, NF_DROP);
                }
        }
        spin_unlock_bh(&queue->lock);
}

static int
nfqnl_put_packet_info(struct sk_buff *nlskb, struct sk_buff *packet,
                      bool csum_verify)
{
        __u32 flags = 0;

        if (packet->ip_summed == CHECKSUM_PARTIAL)
                flags = NFQA_SKB_CSUMNOTREADY;
        else if (csum_verify)
                flags = NFQA_SKB_CSUM_NOTVERIFIED;

        if (skb_is_gso(packet))
                flags |= NFQA_SKB_GSO;

        return flags ? nla_put_be32(nlskb, NFQA_SKB_INFO, htonl(flags)) : 0;
}

static int nfqnl_put_sk_uidgid(struct sk_buff *skb, struct sock *sk)
{
        const struct cred *cred;

        if (!sk_fullsock(sk))
                return 0;

        read_lock_bh(&sk->sk_callback_lock);
        if (sk->sk_socket && sk->sk_socket->file) {
                cred = sk->sk_socket->file->f_cred;
                if (nla_put_be32(skb, NFQA_UID,
                    htonl(from_kuid_munged(&init_user_ns, cred->fsuid))))
                        goto nla_put_failure;
                if (nla_put_be32(skb, NFQA_GID,
                    htonl(from_kgid_munged(&init_user_ns, cred->fsgid))))
                        goto nla_put_failure;
        }
        read_unlock_bh(&sk->sk_callback_lock);
        return 0;

nla_put_failure:
        read_unlock_bh(&sk->sk_callback_lock);
        return -1;
}

static int nfqnl_put_sk_classid(struct sk_buff *skb, struct sock *sk)
{
#if IS_ENABLED(CONFIG_CGROUP_NET_CLASSID)
        if (sk && sk_fullsock(sk)) {
                u32 classid = sock_cgroup_classid(&sk->sk_cgrp_data);

                if (classid && nla_put_be32(skb, NFQA_CGROUP_CLASSID, htonl(classid)))
                        return -1;
        }
#endif
        return 0;
}

static int nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsm_context *ctx)
{
        int seclen = 0;
#if IS_ENABLED(CONFIG_NETWORK_SECMARK)

        if (!skb || !sk_fullsock(skb->sk))
                return 0;

        read_lock_bh(&skb->sk->sk_callback_lock);

        if (skb->secmark)
                seclen = security_secid_to_secctx(skb->secmark, ctx);
        read_unlock_bh(&skb->sk->sk_callback_lock);
#endif
        return seclen;
}

static u32 nfqnl_get_bridge_size(struct nf_queue_entry *entry)
{
        struct sk_buff *entskb = entry->skb;
        u32 nlalen = 0;

        if (entry->state.pf != PF_BRIDGE || !skb_mac_header_was_set(entskb))
                return 0;

        if (skb_vlan_tag_present(entskb))
                nlalen += nla_total_size(nla_total_size(sizeof(__be16)) +
                                         nla_total_size(sizeof(__be16)));

        if (entskb->network_header > entskb->mac_header)
                nlalen += nla_total_size((entskb->network_header -
                                          entskb->mac_header));

        return nlalen;
}

static int nfqnl_put_bridge(struct nf_queue_entry *entry, struct sk_buff *skb)
{
        struct sk_buff *entskb = entry->skb;

        if (entry->state.pf != PF_BRIDGE || !skb_mac_header_was_set(entskb))
                return 0;

        if (skb_vlan_tag_present(entskb)) {
                struct nlattr *nest;

                nest = nla_nest_start(skb, NFQA_VLAN);
                if (!nest)
                        goto nla_put_failure;

                if (nla_put_be16(skb, NFQA_VLAN_TCI, htons(entskb->vlan_tci)) ||
                    nla_put_be16(skb, NFQA_VLAN_PROTO, entskb->vlan_proto))
                        goto nla_put_failure;

                nla_nest_end(skb, nest);
        }

        if (entskb->mac_header < entskb->network_header) {
                int len = (int)(entskb->network_header - entskb->mac_header);

                if (nla_put(skb, NFQA_L2HDR, len, skb_mac_header(entskb)))
                        goto nla_put_failure;
        }

        return 0;

nla_put_failure:
        return -1;
}

static int nf_queue_checksum_help(struct sk_buff *entskb)
{
        if (skb_csum_is_sctp(entskb))
                return skb_crc32c_csum_help(entskb);

        return skb_checksum_help(entskb);
}

static struct sk_buff *
nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
                           struct nf_queue_entry *entry,
                           __be32 **packet_id_ptr)
{
        size_t size;
        size_t data_len = 0, cap_len = 0;
        unsigned int hlen = 0;
        struct sk_buff *skb;
        struct nlattr *nla;
        struct nfqnl_msg_packet_hdr *pmsg;
        struct nlmsghdr *nlh;
        struct sk_buff *entskb = entry->skb;
        struct net_device *indev;
        struct net_device *outdev;
        struct nf_conn *ct = NULL;
        enum ip_conntrack_info ctinfo = 0;
        const struct nfnl_ct_hook *nfnl_ct;
        bool csum_verify;
        struct lsm_context ctx = { NULL, 0, 0 };
        int seclen = 0;
        ktime_t tstamp;

        size = nlmsg_total_size(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 */
#if IS_ENABLED(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(u_int32_t))     /* priority */
                + nla_total_size(sizeof(struct nfqnl_msg_packet_hw))
                + nla_total_size(sizeof(u_int32_t))     /* skbinfo */
#if IS_ENABLED(CONFIG_CGROUP_NET_CLASSID)
                + nla_total_size(sizeof(u_int32_t))     /* classid */
#endif
                + nla_total_size(sizeof(u_int32_t));    /* cap_len */

        tstamp = skb_tstamp_cond(entskb, false);
        if (tstamp)
                size += nla_total_size(sizeof(struct nfqnl_msg_packet_timestamp));

        size += nfqnl_get_bridge_size(entry);

        if (entry->state.hook <= NF_INET_FORWARD ||
           (entry->state.hook == NF_INET_POST_ROUTING && entskb->sk == NULL))
                csum_verify = !skb_csum_unnecessary(entskb);
        else
                csum_verify = false;

        outdev = entry->state.out;

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

        case NFQNL_COPY_PACKET:
                if (!(queue->flags & NFQA_CFG_F_GSO) &&
                    entskb->ip_summed == CHECKSUM_PARTIAL &&
                    nf_queue_checksum_help(entskb))
                        return NULL;

                data_len = READ_ONCE(queue->copy_range);
                if (data_len > entskb->len)
                        data_len = entskb->len;

                hlen = skb_zerocopy_headlen(entskb);
                hlen = min_t(unsigned int, hlen, data_len);
                size += sizeof(struct nlattr) + hlen;
                cap_len = entskb->len;
                break;
        }

        nfnl_ct = rcu_dereference(nfnl_ct_hook);

#if IS_ENABLED(CONFIG_NF_CONNTRACK)
        if (queue->flags & NFQA_CFG_F_CONNTRACK) {
                if (nfnl_ct != NULL) {
                        ct = nf_ct_get(entskb, &ctinfo);
                        if (ct != NULL)
                                size += nfnl_ct->build_size(ct);
                }
        }
#endif

        if (queue->flags & NFQA_CFG_F_UID_GID) {
                size += (nla_total_size(sizeof(u_int32_t))      /* uid */
                        + nla_total_size(sizeof(u_int32_t)));   /* gid */
        }

        if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) {
                seclen = nfqnl_get_sk_secctx(entskb, &ctx);
                if (seclen < 0)
                        return NULL;
                if (seclen)
                        size += nla_total_size(seclen);
        }

        skb = alloc_skb(size, GFP_ATOMIC);
        if (!skb) {
                skb_tx_error(entskb);
                goto nlmsg_failure;
        }

        nlh = nfnl_msg_put(skb, 0, 0,
                           nfnl_msg_type(NFNL_SUBSYS_QUEUE, NFQNL_MSG_PACKET),
                           0, entry->state.pf, NFNETLINK_V0,
                           htons(queue->queue_num));
        if (!nlh) {
                skb_tx_error(entskb);
                kfree_skb(skb);
                goto nlmsg_failure;
        }

        nla = __nla_reserve(skb, NFQA_PACKET_HDR, sizeof(*pmsg));
        pmsg = nla_data(nla);
        pmsg->hw_protocol       = entskb->protocol;
        pmsg->hook              = entry->state.hook;
        *packet_id_ptr          = &pmsg->packet_id;

        indev = entry->state.in;
        if (indev) {
#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
                if (nla_put_be32(skb, NFQA_IFINDEX_INDEV, htonl(indev->ifindex)))
                        goto nla_put_failure;
#else
                if (entry->state.pf == PF_BRIDGE) {
                        /* Case 1: indev is physical input device, we need to
                         * look for bridge group (when called from
                         * netfilter_bridge) */
                        if (nla_put_be32(skb, NFQA_IFINDEX_PHYSINDEV,
                                         htonl(indev->ifindex)) ||
                        /* this is the bridge group "brX" */
                        /* rcu_read_lock()ed by __nf_queue */
                            nla_put_be32(skb, NFQA_IFINDEX_INDEV,
                                         htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
                                goto nla_put_failure;
                } else {
                        int physinif;

                        /* Case 2: indev is bridge group, we need to look for
                         * physical device (when called from ipv4) */
                        if (nla_put_be32(skb, NFQA_IFINDEX_INDEV,
                                         htonl(indev->ifindex)))
                                goto nla_put_failure;

                        physinif = nf_bridge_get_physinif(entskb);
                        if (physinif &&
                            nla_put_be32(skb, NFQA_IFINDEX_PHYSINDEV,
                                         htonl(physinif)))
                                goto nla_put_failure;
                }
#endif
        }

        if (outdev) {
#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
                if (nla_put_be32(skb, NFQA_IFINDEX_OUTDEV, htonl(outdev->ifindex)))
                        goto nla_put_failure;
#else
                if (entry->state.pf == PF_BRIDGE) {
                        /* Case 1: outdev is physical output device, we need to
                         * look for bridge group (when called from
                         * netfilter_bridge) */
                        if (nla_put_be32(skb, NFQA_IFINDEX_PHYSOUTDEV,
                                         htonl(outdev->ifindex)) ||
                        /* this is the bridge group "brX" */
                        /* rcu_read_lock()ed by __nf_queue */
                            nla_put_be32(skb, NFQA_IFINDEX_OUTDEV,
                                         htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
                                goto nla_put_failure;
                } else {
                        int physoutif;

                        /* Case 2: outdev is bridge group, we need to look for
                         * physical output device (when called from ipv4) */
                        if (nla_put_be32(skb, NFQA_IFINDEX_OUTDEV,
                                         htonl(outdev->ifindex)))
                                goto nla_put_failure;

                        physoutif = nf_bridge_get_physoutif(entskb);
                        if (physoutif &&
                            nla_put_be32(skb, NFQA_IFINDEX_PHYSOUTDEV,
                                         htonl(physoutif)))
                                goto nla_put_failure;
                }
#endif
        }

        if (entskb->mark &&
            nla_put_be32(skb, NFQA_MARK, htonl(entskb->mark)))
                goto nla_put_failure;

        if (entskb->priority &&
            nla_put_be32(skb, NFQA_PRIORITY, htonl(entskb->priority)))
                goto nla_put_failure;

        if (indev && entskb->dev &&
            skb_mac_header_was_set(entskb) &&
            skb_mac_header_len(entskb) != 0) {
                struct nfqnl_msg_packet_hw phw;
                int len;

                memset(&phw, 0, sizeof(phw));
                len = dev_parse_header(entskb, phw.hw_addr);
                if (len) {
                        phw.hw_addrlen = htons(len);
                        if (nla_put(skb, NFQA_HWADDR, sizeof(phw), &phw))
                                goto nla_put_failure;
                }
        }

        if (nfqnl_put_bridge(entry, skb) < 0)
                goto nla_put_failure;

        if (entry->state.hook <= NF_INET_FORWARD && tstamp) {
                struct nfqnl_msg_packet_timestamp ts;
                struct timespec64 kts = ktime_to_timespec64(tstamp);

                ts.sec = cpu_to_be64(kts.tv_sec);
                ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);

                if (nla_put(skb, NFQA_TIMESTAMP, sizeof(ts), &ts))
                        goto nla_put_failure;
        }

        if ((queue->flags & NFQA_CFG_F_UID_GID) && entskb->sk &&
            nfqnl_put_sk_uidgid(skb, entskb->sk) < 0)
                goto nla_put_failure;

        if (nfqnl_put_sk_classid(skb, entskb->sk) < 0)
                goto nla_put_failure;

        if (seclen > 0 && nla_put(skb, NFQA_SECCTX, ctx.len, ctx.context))
                goto nla_put_failure;

        if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0)
                goto nla_put_failure;

        if (cap_len > data_len &&
            nla_put_be32(skb, NFQA_CAP_LEN, htonl(cap_len)))
                goto nla_put_failure;

        if (nfqnl_put_packet_info(skb, entskb, csum_verify))
                goto nla_put_failure;

        if (data_len) {
                struct nlattr *nla;

                if (skb_tailroom(skb) < sizeof(*nla) + hlen)
                        goto nla_put_failure;

                nla = skb_put(skb, sizeof(*nla));
                nla->nla_type = NFQA_PAYLOAD;
                nla->nla_len = nla_attr_size(data_len);

                if (skb_zerocopy(skb, entskb, data_len, hlen))
                        goto nla_put_failure;
        }

        nlh->nlmsg_len = skb->len;
        if (seclen >= 0)
                security_release_secctx(&ctx);
        return skb;

nla_put_failure:
        skb_tx_error(entskb);
        kfree_skb(skb);
        net_err_ratelimited("nf_queue: error creating packet message\n");
nlmsg_failure:
        if (seclen >= 0)
                security_release_secctx(&ctx);
        return NULL;
}

static int
__nfqnl_enqueue_packet(struct net *net, struct nfqnl_instance *queue,
                        struct nf_queue_entry *entry)
{
        struct sk_buff *nskb;
        int err = -ENOBUFS;
        __be32 *packet_id_ptr;
        int failopen = 0;

        nskb = nfqnl_build_packet_message(net, queue, entry, &packet_id_ptr);
        if (nskb == NULL) {
                err = -ENOMEM;
                goto err_out;
        }
        spin_lock_bh(&queue->lock);

        if (queue->queue_total >= queue->queue_maxlen)
                goto err_out_queue_drop;

        entry->id = ++queue->id_sequence;
        *packet_id_ptr = htonl(entry->id);

        /* Insert into hash BEFORE unicast. If failure don't send to userspace. */
        err = __enqueue_entry(queue, entry);
        if (unlikely(err))
                goto err_out_queue_drop;

        /* nfnetlink_unicast will either free the nskb or add it to a socket */
        err = nfnetlink_unicast(nskb, net, queue->peer_portid);
        if (err < 0) {
                /* Unicast failed - remove entry we just inserted */
                __dequeue_entry(queue, entry);

                if (queue->flags & NFQA_CFG_F_FAIL_OPEN) {
                        failopen = 1;
                        err = 0;
                } else {
                        queue->queue_user_dropped++;
                }
                goto err_out_unlock;
        }

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

err_out_queue_drop:
        if (queue->flags & NFQA_CFG_F_FAIL_OPEN) {
                failopen = 1;
                err = 0;
        } else {
                queue->queue_dropped++;

                if (queue->queue_total >= queue->queue_maxlen)
                        net_warn_ratelimited("nf_queue: full at %d entries, dropping packets(s)\n",
                                             queue->queue_total);
                else
                        net_warn_ratelimited("nf_queue: hash insert failed: %d\n", err);
        }
        kfree_skb(nskb);
err_out_unlock:
        spin_unlock_bh(&queue->lock);
        if (failopen)
                nfqnl_reinject(entry, NF_ACCEPT);
err_out:
        return err;
}

static struct nf_queue_entry *
nf_queue_entry_dup(struct nf_queue_entry *e)
{
        struct nf_queue_entry *entry = kmemdup(e, e->size, GFP_ATOMIC);

        if (!entry)
                return NULL;

        if (nf_queue_entry_get_refs(entry))
                return entry;

        kfree(entry);
        return NULL;
}

#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
/* When called from bridge netfilter, skb->data must point to MAC header
 * before calling skb_gso_segment(). Else, original MAC header is lost
 * and segmented skbs will be sent to wrong destination.
 */
static void nf_bridge_adjust_skb_data(struct sk_buff *skb)
{
        if (nf_bridge_info_get(skb))
                __skb_push(skb, skb->network_header - skb->mac_header);
}

static void nf_bridge_adjust_segmented_data(struct sk_buff *skb)
{
        if (nf_bridge_info_get(skb))
                __skb_pull(skb, skb->network_header - skb->mac_header);
}
#else
#define nf_bridge_adjust_skb_data(s) do {} while (0)
#define nf_bridge_adjust_segmented_data(s) do {} while (0)
#endif

static int
__nfqnl_enqueue_packet_gso(struct net *net, struct nfqnl_instance *queue,
                           struct sk_buff *skb, struct nf_queue_entry *entry)
{
        int ret = -ENOMEM;
        struct nf_queue_entry *entry_seg;

        nf_bridge_adjust_segmented_data(skb);

        if (skb->next == NULL) { /* last packet, no need to copy entry */
                struct sk_buff *gso_skb = entry->skb;
                entry->skb = skb;
                ret = __nfqnl_enqueue_packet(net, queue, entry);
                if (ret)
                        entry->skb = gso_skb;
                return ret;
        }

        skb_mark_not_on_list(skb);

        entry_seg = nf_queue_entry_dup(entry);
        if (entry_seg) {
                entry_seg->skb = skb;
                ret = __nfqnl_enqueue_packet(net, queue, entry_seg);
                if (ret)
                        nf_queue_entry_free(entry_seg);
        }
        return ret;
}

static int
nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
{
        struct sk_buff *skb, *segs, *nskb;
        bool ct_is_unconfirmed = false;
        struct nfqnl_instance *queue;
        unsigned int queued;
        int err = -ENOBUFS;
        struct net *net = entry->state.net;
        struct nfnl_queue_net *q = nfnl_queue_pernet(net);

        /* rcu_read_lock()ed by nf_hook_thresh */
        queue = instance_lookup(q, queuenum);
        if (!queue)
                return -ESRCH;

        if (queue->copy_mode == NFQNL_COPY_NONE)
                return -EINVAL;

        skb = entry->skb;

        switch (entry->state.pf) {
        case NFPROTO_IPV4:
                skb->protocol = htons(ETH_P_IP);
                break;
        case NFPROTO_IPV6:
                skb->protocol = htons(ETH_P_IPV6);
                break;
        }

        /* Check if someone already holds another reference to
         * unconfirmed ct.  If so, we cannot queue the skb:
         * concurrent modifications of nf_conn->ext are not
         * allowed and we can't know if another CPU isn't
         * processing the same nf_conn entry in parallel.
         */
        if (nf_ct_drop_unconfirmed(entry, &ct_is_unconfirmed))
                return -EINVAL;

        if (!skb_is_gso(skb) || ((queue->flags & NFQA_CFG_F_GSO) && !skb_is_gso_sctp(skb)))
                return __nfqnl_enqueue_packet(net, queue, entry);

        nf_bridge_adjust_skb_data(skb);
        segs = skb_gso_segment(skb, 0);
        /* Does not use PTR_ERR to limit the number of error codes that can be
         * returned by nf_queue.  For instance, callers rely on -ESRCH to
         * mean 'ignore this hook'.
         */
        if (IS_ERR_OR_NULL(segs))
                goto out_err;
        queued = 0;
        err = 0;

        skb_list_walk_safe(segs, segs, nskb) {
                if (ct_is_unconfirmed && queued > 0) {
                        /* skb_gso_segment() increments the ct refcount.
                         * This is a problem for unconfirmed (not in hash)
                         * entries, those can race when reinjections happen
                         * in parallel.
                         *
                         * Annotate this for all queued entries except the
                         * first one.
                         *
                         * As long as the first one is reinjected first it
                         * will do the confirmation for us.
                         */
                        entry->nf_ct_is_unconfirmed = ct_is_unconfirmed;
                }

                if (err == 0)
                        err = __nfqnl_enqueue_packet_gso(net, queue,
                                                        segs, entry);
                if (err == 0)
                        queued++;
                else
                        kfree_skb(segs);
        }

        if (queued) {
                if (err) /* some segments are already queued */
                        nf_queue_entry_free(entry);
                kfree_skb(skb);
                return 0;
        }
 out_err:
        nf_bridge_adjust_segmented_data(skb);
        return err;
}

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

        if (diff < 0) {
                unsigned int min_len = skb_transport_offset(e->skb);

                if (data_len < min_len)
                        return -EINVAL;

                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)) {
                        nskb = skb_copy_expand(e->skb, skb_headroom(e->skb),
                                               diff, GFP_ATOMIC);
                        if (!nskb)
                                return -ENOMEM;
                        kfree_skb(e->skb);
                        e->skb = nskb;
                }
                skb_put(e->skb, diff);
        }
        if (skb_ensure_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;
                if (range == 0 || range > NFQNL_MAX_COPY_RANGE)
                        queue->copy_range = NFQNL_MAX_COPY_RANGE;
                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 IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
        int physinif, physoutif;

        physinif = nf_bridge_get_physinif(entry->skb);
        physoutif = nf_bridge_get_physoutif(entry->skb);

        if (physinif == ifindex || physoutif == ifindex)
                return 1;
#endif
        if (entry->state.in)
                if (entry->state.in->ifindex == ifindex)
                        return 1;
        if (entry->state.out)
                if (entry->state.out->ifindex == ifindex)
                        return 1;

        return 0;
}

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

        rcu_read_lock();

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

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

        rcu_read_unlock();
}

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

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

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

static void nfqnl_nf_hook_drop(struct net *net)
{
        struct nfnl_queue_net *q = nfnl_queue_pernet(net);
        int i;

        /* This function is also called on net namespace error unwind,
         * when pernet_ops->init() failed and ->exit() functions of the
         * previous pernet_ops gets called.
         *
         * This may result in a call to nfqnl_nf_hook_drop() before
         * struct nfnl_queue_net was allocated.
         */
        if (!q)
                return;

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

                hlist_for_each_entry_rcu(inst, head, hlist)
                        nfqnl_flush(inst, NULL, 0);
        }
}

static int
nfqnl_rcv_nl_event(struct notifier_block *this,
                   unsigned long event, void *ptr)
{
        struct netlink_notify *n = ptr;
        struct nfnl_queue_net *q = nfnl_queue_pernet(n->net);

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

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

                        hlist_for_each_entry_safe(inst, t2, head, hlist) {
                                if (n->portid == inst->peer_portid)
                                        __instance_destroy(inst);
                        }
                }
                spin_unlock(&q->instances_lock);
        }
        return NOTIFY_DONE;
}

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

static const struct nla_policy nfqa_vlan_policy[NFQA_VLAN_MAX + 1] = {
        [NFQA_VLAN_TCI]         = { .type = NLA_U16},
        [NFQA_VLAN_PROTO]       = { .type = NLA_U16},
};

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 },
        [NFQA_CT]               = { .type = NLA_UNSPEC },
        [NFQA_EXP]              = { .type = NLA_UNSPEC },
        [NFQA_VLAN]             = { .type = NLA_NESTED },
        [NFQA_PRIORITY]         = { .type = NLA_U32 },
};

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

static struct nfqnl_instance *
verdict_instance_lookup(struct nfnl_queue_net *q, u16 queue_num, u32 nlportid)
{
        struct nfqnl_instance *queue;

        queue = instance_lookup(q, queue_num);
        if (!queue)
                return ERR_PTR(-ENODEV);

        if (queue->peer_portid != nlportid)
                return ERR_PTR(-EPERM);

        return queue;
}

static struct nfqnl_msg_verdict_hdr*
verdicthdr_get(const struct nlattr * const nfqa[])
{
        struct nfqnl_msg_verdict_hdr *vhdr;
        unsigned int verdict;

        if (!nfqa[NFQA_VERDICT_HDR])
                return NULL;

        vhdr = nla_data(nfqa[NFQA_VERDICT_HDR]);
        verdict = ntohl(vhdr->verdict) & NF_VERDICT_MASK;
        if (verdict > NF_MAX_VERDICT || verdict == NF_STOLEN)
                return NULL;
        return vhdr;
}

static int nfq_id_after(unsigned int id, unsigned int max)
{
        return (int)(id - max) > 0;
}

static int nfqnl_recv_verdict_batch(struct sk_buff *skb,
                                    const struct nfnl_info *info,
                                    const struct nlattr * const nfqa[])
{
        struct nfnl_queue_net *q = nfnl_queue_pernet(info->net);
        u16 queue_num = ntohs(info->nfmsg->res_id);
        struct nf_queue_entry *entry, *tmp;
        struct nfqnl_msg_verdict_hdr *vhdr;
        struct nfqnl_instance *queue;
        unsigned int verdict, maxid;
        LIST_HEAD(batch_list);

        queue = verdict_instance_lookup(q, queue_num,
                                        NETLINK_CB(skb).portid);
        if (IS_ERR(queue))
                return PTR_ERR(queue);

        vhdr = verdicthdr_get(nfqa);
        if (!vhdr)
                return -EINVAL;

        verdict = ntohl(vhdr->verdict);
        maxid = ntohl(vhdr->id);

        spin_lock_bh(&queue->lock);

        list_for_each_entry_safe(entry, tmp, &queue->queue_list, list) {
                if (nfq_id_after(entry->id, maxid))
                        break;
                __dequeue_entry(queue, entry);
                list_add_tail(&entry->list, &batch_list);
        }

        spin_unlock_bh(&queue->lock);

        if (list_empty(&batch_list))
                return -ENOENT;

        list_for_each_entry_safe(entry, tmp, &batch_list, list) {
                if (nfqa[NFQA_MARK])
                        entry->skb->mark = ntohl(nla_get_be32(nfqa[NFQA_MARK]));

                if (nfqa[NFQA_PRIORITY])
                        entry->skb->priority = ntohl(nla_get_be32(nfqa[NFQA_PRIORITY]));

                nfqnl_reinject(entry, verdict);
        }
        return 0;
}

static struct nf_conn *nfqnl_ct_parse(const struct nfnl_ct_hook *nfnl_ct,
                                      const struct nlmsghdr *nlh,
                                      const struct nlattr * const nfqa[],
                                      struct nf_queue_entry *entry,
                                      enum ip_conntrack_info *ctinfo)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
        struct nf_conn *ct;

        ct = nf_ct_get(entry->skb, ctinfo);
        if (ct == NULL)
                return NULL;

        if (nfnl_ct->parse(nfqa[NFQA_CT], ct) < 0)
                return NULL;

        if (nfqa[NFQA_EXP])
                nfnl_ct->attach_expect(nfqa[NFQA_EXP], ct,
                                      NETLINK_CB(entry->skb).portid,
                                      nlmsg_report(nlh));
        return ct;
#else
        return NULL;
#endif
}

static int nfqa_parse_bridge(struct nf_queue_entry *entry,
                             const struct nlattr * const nfqa[])
{
        if (nfqa[NFQA_VLAN]) {
                struct nlattr *tb[NFQA_VLAN_MAX + 1];
                int err;

                err = nla_parse_nested_deprecated(tb, NFQA_VLAN_MAX,
                                                  nfqa[NFQA_VLAN],
                                                  nfqa_vlan_policy, NULL);
                if (err < 0)
                        return err;

                if (!tb[NFQA_VLAN_TCI] || !tb[NFQA_VLAN_PROTO])
                        return -EINVAL;

                __vlan_hwaccel_put_tag(entry->skb,
                        nla_get_be16(tb[NFQA_VLAN_PROTO]),
                        ntohs(nla_get_be16(tb[NFQA_VLAN_TCI])));
        }

        if (nfqa[NFQA_L2HDR]) {
                int mac_header_len = entry->skb->network_header -
                        entry->skb->mac_header;

                if (mac_header_len != nla_len(nfqa[NFQA_L2HDR]))
                        return -EINVAL;
                else if (mac_header_len > 0)
                        memcpy(skb_mac_header(entry->skb),
                               nla_data(nfqa[NFQA_L2HDR]),
                               mac_header_len);
        }

        return 0;
}

static int nfqnl_recv_verdict(struct sk_buff *skb, const struct nfnl_info *info,
                              const struct nlattr * const nfqa[])
{
        struct nfnl_queue_net *q = nfnl_queue_pernet(info->net);
        u_int16_t queue_num = ntohs(info->nfmsg->res_id);
        const struct nfnl_ct_hook *nfnl_ct;
        struct nfqnl_msg_verdict_hdr *vhdr;
        enum ip_conntrack_info ctinfo;
        struct nfqnl_instance *queue;
        struct nf_queue_entry *entry;
        struct nf_conn *ct = NULL;
        unsigned int verdict;
        int err;

        queue = verdict_instance_lookup(q, queue_num,
                                        NETLINK_CB(skb).portid);
        if (IS_ERR(queue))
                return PTR_ERR(queue);

        vhdr = verdicthdr_get(nfqa);
        if (!vhdr)
                return -EINVAL;

        verdict = ntohl(vhdr->verdict);

        entry = find_dequeue_entry(queue, ntohl(vhdr->id), info->net);
        if (entry == NULL)
                return -ENOENT;

        /* rcu lock already held from nfnl->call_rcu. */
        nfnl_ct = rcu_dereference(nfnl_ct_hook);

        if (nfqa[NFQA_CT]) {
                if (nfnl_ct != NULL)
                        ct = nfqnl_ct_parse(nfnl_ct, info->nlh, nfqa, entry,
                                            &ctinfo);
        }

        if (entry->state.pf == PF_BRIDGE) {
                err = nfqa_parse_bridge(entry, nfqa);
                if (err < 0) {
                        nfqnl_reinject(entry, NF_DROP);
                        return err;
                }
        }

        if (nfqa[NFQA_PAYLOAD]) {
                u16 payload_len = nla_len(nfqa[NFQA_PAYLOAD]);
                int diff = payload_len - entry->skb->len;

                if (nfqnl_mangle(nla_data(nfqa[NFQA_PAYLOAD]),
                                 payload_len, entry, diff) < 0)
                        verdict = NF_DROP;

                if (ct && diff)
                        nfnl_ct->seq_adjust(entry->skb, ct, ctinfo, diff);
        }

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

        if (nfqa[NFQA_PRIORITY])
                entry->skb->priority = ntohl(nla_get_be32(nfqa[NFQA_PRIORITY]));

        nfqnl_reinject(entry, verdict);
        return 0;
}

static int nfqnl_recv_unsupp(struct sk_buff *skb, const struct nfnl_info *info,
                             const struct nlattr * const cda[])
{
        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) },
        [NFQA_CFG_QUEUE_MAXLEN] = { .type = NLA_U32 },
        [NFQA_CFG_MASK]         = { .type = NLA_U32 },
        [NFQA_CFG_FLAGS]        = { .type = NLA_U32 },
};

static const struct nf_queue_handler nfqh = {
        .outfn          = nfqnl_enqueue_packet,
        .nf_hook_drop   = nfqnl_nf_hook_drop,
};

static int nfqnl_recv_config(struct sk_buff *skb, const struct nfnl_info *info,
                             const struct nlattr * const nfqa[])
{
        struct nfnl_queue_net *q = nfnl_queue_pernet(info->net);
        u_int16_t queue_num = ntohs(info->nfmsg->res_id);
        struct nfqnl_msg_config_cmd *cmd = NULL;
        struct nfqnl_instance *queue;
        __u32 flags = 0, mask = 0;

        WARN_ON_ONCE(!lockdep_nfnl_is_held(NFNL_SUBSYS_QUEUE));

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

                /* Obsolete commands without queue context */
                switch (cmd->command) {
                case NFQNL_CFG_CMD_PF_BIND: return 0;
                case NFQNL_CFG_CMD_PF_UNBIND: return 0;
                }
        }

        /* Check if we support these flags in first place, dependencies should
         * be there too not to break atomicity.
         */
        if (nfqa[NFQA_CFG_FLAGS]) {
                if (!nfqa[NFQA_CFG_MASK]) {
                        /* A mask is needed to specify which flags are being
                         * changed.
                         */
                        return -EINVAL;
                }

                flags = ntohl(nla_get_be32(nfqa[NFQA_CFG_FLAGS]));
                mask = ntohl(nla_get_be32(nfqa[NFQA_CFG_MASK]));

                if (flags >= NFQA_CFG_F_MAX)
                        return -EOPNOTSUPP;

#if !IS_ENABLED(CONFIG_NETWORK_SECMARK)
                if (flags & mask & NFQA_CFG_F_SECCTX)
                        return -EOPNOTSUPP;
#endif
                if ((flags & mask & NFQA_CFG_F_CONNTRACK) &&
                    !rcu_access_pointer(nfnl_ct_hook)) {
#ifdef CONFIG_MODULES
                        nfnl_unlock(NFNL_SUBSYS_QUEUE);
                        request_module("ip_conntrack_netlink");
                        nfnl_lock(NFNL_SUBSYS_QUEUE);
                        if (rcu_access_pointer(nfnl_ct_hook))
                                return -EAGAIN;
#endif
                        return -EOPNOTSUPP;
                }
        }

        /* Lookup queue under RCU. After peer_portid check (or for new queue
         * in BIND case), the queue is owned by the socket sending this message.
         * A socket cannot simultaneously send a message and close, so while
         * processing this CONFIG message, nfqnl_rcv_nl_event() (triggered by
         * socket close) cannot destroy this queue. Safe to use without RCU.
         */
        rcu_read_lock();
        queue = instance_lookup(q, queue_num);
        if (queue && queue->peer_portid != NETLINK_CB(skb).portid) {
                rcu_read_unlock();
                return -EPERM;
        }
        rcu_read_unlock();

        if (cmd != NULL) {
                switch (cmd->command) {
                case NFQNL_CFG_CMD_BIND:
                        if (queue)
                                return -EBUSY;
                        queue = instance_create(q, queue_num, NETLINK_CB(skb).portid);
                        if (IS_ERR(queue))
                                return PTR_ERR(queue);
                        break;
                case NFQNL_CFG_CMD_UNBIND:
                        if (!queue)
                                return -ENODEV;
                        instance_destroy(q, queue);
                        return 0;
                case NFQNL_CFG_CMD_PF_BIND:
                case NFQNL_CFG_CMD_PF_UNBIND:
                        break;
                default:
                        return -EOPNOTSUPP;
                }
        }

        if (!queue)
                return -ENODEV;

        if (nfqa[NFQA_CFG_PARAMS]) {
                struct nfqnl_msg_config_params *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 = nla_data(nfqa[NFQA_CFG_QUEUE_MAXLEN]);

                spin_lock_bh(&queue->lock);
                queue->queue_maxlen = ntohl(*queue_maxlen);
                spin_unlock_bh(&queue->lock);
        }

        if (nfqa[NFQA_CFG_FLAGS]) {
                spin_lock_bh(&queue->lock);
                queue->flags &= ~mask;
                queue->flags |= flags & mask;
                spin_unlock_bh(&queue->lock);
        }

        return 0;
}

static const struct nfnl_callback nfqnl_cb[NFQNL_MSG_MAX] = {
        [NFQNL_MSG_PACKET]      = {
                .call           = nfqnl_recv_unsupp,
                .type           = NFNL_CB_RCU,
                .attr_count     = NFQA_MAX,
        },
        [NFQNL_MSG_VERDICT]     = {
                .call           = nfqnl_recv_verdict,
                .type           = NFNL_CB_RCU,
                .attr_count     = NFQA_MAX,
                .policy         = nfqa_verdict_policy
        },
        [NFQNL_MSG_CONFIG]      = {
                .call           = nfqnl_recv_config,
                .type           = NFNL_CB_MUTEX,
                .attr_count     = NFQA_CFG_MAX,
                .policy         = nfqa_cfg_policy
        },
        [NFQNL_MSG_VERDICT_BATCH] = {
                .call           = nfqnl_recv_verdict_batch,
                .type           = NFNL_CB_RCU,
                .attr_count     = NFQA_MAX,
                .policy         = nfqa_verdict_batch_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 {
        struct seq_net_private p;
        unsigned int bucket;
};

static struct hlist_node *get_first(struct seq_file *seq)
{
        struct iter_state *st = seq->private;
        struct net *net;
        struct nfnl_queue_net *q;

        if (!st)
                return NULL;

        net = seq_file_net(seq);
        q = nfnl_queue_pernet(net);
        for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
                if (!hlist_empty(&q->instance_table[st->bucket]))
                        return q->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;
        struct net *net = seq_file_net(seq);

        h = h->next;
        while (!h) {
                struct nfnl_queue_net *q;

                if (++st->bucket >= INSTANCE_BUCKETS)
                        return NULL;

                q = nfnl_queue_pernet(net);
                h = q->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 *s, loff_t *pos)
        __acquires(nfnl_queue_pernet(seq_file_net(s))->instances_lock)
{
        spin_lock(&nfnl_queue_pernet(seq_file_net(s))->instances_lock);
        return get_idx(s, *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)
        __releases(nfnl_queue_pernet(seq_file_net(s))->instances_lock)
{
        spin_unlock(&nfnl_queue_pernet(seq_file_net(s))->instances_lock);
}

static int seq_show(struct seq_file *s, void *v)
{
        const struct nfqnl_instance *inst = v;

        seq_printf(s, "%5u %6u %5u %1u %5u %5u %5u %8u %2d\n",
                   inst->queue_num,
                   inst->peer_portid, inst->queue_total,
                   inst->copy_mode, inst->copy_range,
                   inst->queue_dropped, inst->queue_user_dropped,
                   inst->id_sequence, 1);
        return 0;
}

static const struct seq_operations nfqnl_seq_ops = {
        .start  = seq_start,
        .next   = seq_next,
        .stop   = seq_stop,
        .show   = seq_show,
};
#endif /* PROC_FS */

static int __net_init nfnl_queue_net_init(struct net *net)
{
        unsigned int i;
        struct nfnl_queue_net *q = nfnl_queue_pernet(net);

        for (i = 0; i < INSTANCE_BUCKETS; i++)
                INIT_HLIST_HEAD(&q->instance_table[i]);

        spin_lock_init(&q->instances_lock);

#ifdef CONFIG_PROC_FS
        if (!proc_create_net("nfnetlink_queue", 0440, net->nf.proc_netfilter,
                        &nfqnl_seq_ops, sizeof(struct iter_state)))
                return -ENOMEM;
#endif
        return 0;
}

static void __net_exit nfnl_queue_net_exit(struct net *net)
{
        struct nfnl_queue_net *q = nfnl_queue_pernet(net);
        unsigned int i;

#ifdef CONFIG_PROC_FS
        remove_proc_entry("nfnetlink_queue", net->nf.proc_netfilter);
#endif
        for (i = 0; i < INSTANCE_BUCKETS; i++)
                WARN_ON_ONCE(!hlist_empty(&q->instance_table[i]));
}

static struct pernet_operations nfnl_queue_net_ops = {
        .init           = nfnl_queue_net_init,
        .exit           = nfnl_queue_net_exit,
        .id             = &nfnl_queue_net_id,
        .size           = sizeof(struct nfnl_queue_net),
};

static int __init nfnetlink_queue_init(void)
{
        int status;

        status = rhashtable_init(&nfqnl_packet_map, &nfqnl_rhashtable_params);
        if (status < 0)
                return status;

        status = register_pernet_subsys(&nfnl_queue_net_ops);
        if (status < 0) {
                pr_err("failed to register pernet ops\n");
                goto cleanup_rhashtable;
        }

        netlink_register_notifier(&nfqnl_rtnl_notifier);
        status = nfnetlink_subsys_register(&nfqnl_subsys);
        if (status < 0) {
                pr_err("failed to create netlink socket\n");
                goto cleanup_netlink_notifier;
        }

        status = register_netdevice_notifier(&nfqnl_dev_notifier);
        if (status < 0) {
                pr_err("failed to register netdevice notifier\n");
                goto cleanup_netlink_subsys;
        }

        nf_register_queue_handler(&nfqh);

        return status;

cleanup_netlink_subsys:
        nfnetlink_subsys_unregister(&nfqnl_subsys);
cleanup_netlink_notifier:
        netlink_unregister_notifier(&nfqnl_rtnl_notifier);
        unregister_pernet_subsys(&nfnl_queue_net_ops);
cleanup_rhashtable:
        rhashtable_destroy(&nfqnl_packet_map);
        return status;
}

static void __exit nfnetlink_queue_fini(void)
{
        nf_unregister_queue_handler();
        unregister_netdevice_notifier(&nfqnl_dev_notifier);
        nfnetlink_subsys_unregister(&nfqnl_subsys);
        netlink_unregister_notifier(&nfqnl_rtnl_notifier);
        unregister_pernet_subsys(&nfnl_queue_net_ops);

        rhashtable_destroy(&nfqnl_packet_map);

        rcu_barrier(); /* Wait for completion of call_rcu()'s */
}

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);