net_sched: switch to rcu_work

[mirror_ubuntu-hirsute-kernel.git] / net / sched / cls_u32.c

/*
 * net/sched/cls_u32.c  Ugly (or Universal) 32bit key Packet Classifier.
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *      The filters are packed to hash tables of key nodes
 *      with a set of 32bit key/mask pairs at every node.
 *      Nodes reference next level hash tables etc.
 *
 *      This scheme is the best universal classifier I managed to
 *      invent; it is not super-fast, but it is not slow (provided you
 *      program it correctly), and general enough.  And its relative
 *      speed grows as the number of rules becomes larger.
 *
 *      It seems that it represents the best middle point between
 *      speed and manageability both by human and by machine.
 *
 *      It is especially useful for link sharing combined with QoS;
 *      pure RSVP doesn't need such a general approach and can use
 *      much simpler (and faster) schemes, sort of cls_rsvp.c.
 *
 *      JHS: We should remove the CONFIG_NET_CLS_IND from here
 *      eventually when the meta match extension is made available
 *
 *      nfmark match added by Catalin(ux aka Dino) BOIE <catab at umbrella.ro>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/percpu.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/bitmap.h>
#include <linux/netdevice.h>
#include <linux/hash.h>
#include <net/netlink.h>
#include <net/act_api.h>
#include <net/pkt_cls.h>
#include <linux/idr.h>

struct tc_u_knode {
        struct tc_u_knode __rcu *next;
        u32                     handle;
        struct tc_u_hnode __rcu *ht_up;
        struct tcf_exts         exts;
#ifdef CONFIG_NET_CLS_IND
        int                     ifindex;
#endif
        u8                      fshift;
        struct tcf_result       res;
        struct tc_u_hnode __rcu *ht_down;
#ifdef CONFIG_CLS_U32_PERF
        struct tc_u32_pcnt __percpu *pf;
#endif
        u32                     flags;
#ifdef CONFIG_CLS_U32_MARK
        u32                     val;
        u32                     mask;
        u32 __percpu            *pcpu_success;
#endif
        struct tcf_proto        *tp;
        struct rcu_work         rwork;
        /* The 'sel' field MUST be the last field in structure to allow for
         * tc_u32_keys allocated at end of structure.
         */
        struct tc_u32_sel       sel;
};

struct tc_u_hnode {
        struct tc_u_hnode __rcu *next;
        u32                     handle;
        u32                     prio;
        struct tc_u_common      *tp_c;
        int                     refcnt;
        unsigned int            divisor;
        struct idr              handle_idr;
        struct rcu_head         rcu;
        u32                     flags;
        /* The 'ht' field MUST be the last field in structure to allow for
         * more entries allocated at end of structure.
         */
        struct tc_u_knode __rcu *ht[1];
};

struct tc_u_common {
        struct tc_u_hnode __rcu *hlist;
        void                    *ptr;
        int                     refcnt;
        struct idr              handle_idr;
        struct hlist_node       hnode;
        struct rcu_head         rcu;
};

static inline unsigned int u32_hash_fold(__be32 key,
                                         const struct tc_u32_sel *sel,
                                         u8 fshift)
{
        unsigned int h = ntohl(key & sel->hmask) >> fshift;

        return h;
}

static int u32_classify(struct sk_buff *skb, const struct tcf_proto *tp,
                        struct tcf_result *res)
{
        struct {
                struct tc_u_knode *knode;
                unsigned int      off;
        } stack[TC_U32_MAXDEPTH];

        struct tc_u_hnode *ht = rcu_dereference_bh(tp->root);
        unsigned int off = skb_network_offset(skb);
        struct tc_u_knode *n;
        int sdepth = 0;
        int off2 = 0;
        int sel = 0;
#ifdef CONFIG_CLS_U32_PERF
        int j;
#endif
        int i, r;

next_ht:
        n = rcu_dereference_bh(ht->ht[sel]);

next_knode:
        if (n) {
                struct tc_u32_key *key = n->sel.keys;

#ifdef CONFIG_CLS_U32_PERF
                __this_cpu_inc(n->pf->rcnt);
                j = 0;
#endif

                if (tc_skip_sw(n->flags)) {
                        n = rcu_dereference_bh(n->next);
                        goto next_knode;
                }

#ifdef CONFIG_CLS_U32_MARK
                if ((skb->mark & n->mask) != n->val) {
                        n = rcu_dereference_bh(n->next);
                        goto next_knode;
                } else {
                        __this_cpu_inc(*n->pcpu_success);
                }
#endif

                for (i = n->sel.nkeys; i > 0; i--, key++) {
                        int toff = off + key->off + (off2 & key->offmask);
                        __be32 *data, hdata;

                        if (skb_headroom(skb) + toff > INT_MAX)
                                goto out;

                        data = skb_header_pointer(skb, toff, 4, &hdata);
                        if (!data)
                                goto out;
                        if ((*data ^ key->val) & key->mask) {
                                n = rcu_dereference_bh(n->next);
                                goto next_knode;
                        }
#ifdef CONFIG_CLS_U32_PERF
                        __this_cpu_inc(n->pf->kcnts[j]);
                        j++;
#endif
                }

                ht = rcu_dereference_bh(n->ht_down);
                if (!ht) {
check_terminal:
                        if (n->sel.flags & TC_U32_TERMINAL) {

                                *res = n->res;
#ifdef CONFIG_NET_CLS_IND
                                if (!tcf_match_indev(skb, n->ifindex)) {
                                        n = rcu_dereference_bh(n->next);
                                        goto next_knode;
                                }
#endif
#ifdef CONFIG_CLS_U32_PERF
                                __this_cpu_inc(n->pf->rhit);
#endif
                                r = tcf_exts_exec(skb, &n->exts, res);
                                if (r < 0) {
                                        n = rcu_dereference_bh(n->next);
                                        goto next_knode;
                                }

                                return r;
                        }
                        n = rcu_dereference_bh(n->next);
                        goto next_knode;
                }

                /* PUSH */
                if (sdepth >= TC_U32_MAXDEPTH)
                        goto deadloop;
                stack[sdepth].knode = n;
                stack[sdepth].off = off;
                sdepth++;

                ht = rcu_dereference_bh(n->ht_down);
                sel = 0;
                if (ht->divisor) {
                        __be32 *data, hdata;

                        data = skb_header_pointer(skb, off + n->sel.hoff, 4,
                                                  &hdata);
                        if (!data)
                                goto out;
                        sel = ht->divisor & u32_hash_fold(*data, &n->sel,
                                                          n->fshift);
                }
                if (!(n->sel.flags & (TC_U32_VAROFFSET | TC_U32_OFFSET | TC_U32_EAT)))
                        goto next_ht;

                if (n->sel.flags & (TC_U32_OFFSET | TC_U32_VAROFFSET)) {
                        off2 = n->sel.off + 3;
                        if (n->sel.flags & TC_U32_VAROFFSET) {
                                __be16 *data, hdata;

                                data = skb_header_pointer(skb,
                                                          off + n->sel.offoff,
                                                          2, &hdata);
                                if (!data)
                                        goto out;
                                off2 += ntohs(n->sel.offmask & *data) >>
                                        n->sel.offshift;
                        }
                        off2 &= ~3;
                }
                if (n->sel.flags & TC_U32_EAT) {
                        off += off2;
                        off2 = 0;
                }

                if (off < skb->len)
                        goto next_ht;
        }

        /* POP */
        if (sdepth--) {
                n = stack[sdepth].knode;
                ht = rcu_dereference_bh(n->ht_up);
                off = stack[sdepth].off;
                goto check_terminal;
        }
out:
        return -1;

deadloop:
        net_warn_ratelimited("cls_u32: dead loop\n");
        return -1;
}

static struct tc_u_hnode *u32_lookup_ht(struct tc_u_common *tp_c, u32 handle)
{
        struct tc_u_hnode *ht;

        for (ht = rtnl_dereference(tp_c->hlist);
             ht;
             ht = rtnl_dereference(ht->next))
                if (ht->handle == handle)
                        break;

        return ht;
}

static struct tc_u_knode *u32_lookup_key(struct tc_u_hnode *ht, u32 handle)
{
        unsigned int sel;
        struct tc_u_knode *n = NULL;

        sel = TC_U32_HASH(handle);
        if (sel > ht->divisor)
                goto out;

        for (n = rtnl_dereference(ht->ht[sel]);
             n;
             n = rtnl_dereference(n->next))
                if (n->handle == handle)
                        break;
out:
        return n;
}


static void *u32_get(struct tcf_proto *tp, u32 handle)
{
        struct tc_u_hnode *ht;
        struct tc_u_common *tp_c = tp->data;

        if (TC_U32_HTID(handle) == TC_U32_ROOT)
                ht = rtnl_dereference(tp->root);
        else
                ht = u32_lookup_ht(tp_c, TC_U32_HTID(handle));

        if (!ht)
                return NULL;

        if (TC_U32_KEY(handle) == 0)
                return ht;

        return u32_lookup_key(ht, handle);
}

/* Protected by rtnl lock */
static u32 gen_new_htid(struct tc_u_common *tp_c, struct tc_u_hnode *ptr)
{
        int id = idr_alloc_cyclic(&tp_c->handle_idr, ptr, 1, 0x7FF, GFP_KERNEL);
        if (id < 0)
                return 0;
        return (id | 0x800U) << 20;
}

static struct hlist_head *tc_u_common_hash;

#define U32_HASH_SHIFT 10
#define U32_HASH_SIZE (1 << U32_HASH_SHIFT)

static void *tc_u_common_ptr(const struct tcf_proto *tp)
{
        struct tcf_block *block = tp->chain->block;

        /* The block sharing is currently supported only
         * for classless qdiscs. In that case we use block
         * for tc_u_common identification. In case the
         * block is not shared, block->q is a valid pointer
         * and we can use that. That works for classful qdiscs.
         */
        if (tcf_block_shared(block))
                return block;
        else
                return block->q;
}

static unsigned int tc_u_hash(const struct tcf_proto *tp)
{
        return hash_ptr(tc_u_common_ptr(tp), U32_HASH_SHIFT);
}

static struct tc_u_common *tc_u_common_find(const struct tcf_proto *tp)
{
        struct tc_u_common *tc;
        unsigned int h;

        h = tc_u_hash(tp);
        hlist_for_each_entry(tc, &tc_u_common_hash[h], hnode) {
                if (tc->ptr == tc_u_common_ptr(tp))
                        return tc;
        }
        return NULL;
}

static int u32_init(struct tcf_proto *tp)
{
        struct tc_u_hnode *root_ht;
        struct tc_u_common *tp_c;
        unsigned int h;

        tp_c = tc_u_common_find(tp);

        root_ht = kzalloc(sizeof(*root_ht), GFP_KERNEL);
        if (root_ht == NULL)
                return -ENOBUFS;

        root_ht->refcnt++;
        root_ht->handle = tp_c ? gen_new_htid(tp_c, root_ht) : 0x80000000;
        root_ht->prio = tp->prio;
        idr_init(&root_ht->handle_idr);

        if (tp_c == NULL) {
                tp_c = kzalloc(sizeof(*tp_c), GFP_KERNEL);
                if (tp_c == NULL) {
                        kfree(root_ht);
                        return -ENOBUFS;
                }
                tp_c->ptr = tc_u_common_ptr(tp);
                INIT_HLIST_NODE(&tp_c->hnode);
                idr_init(&tp_c->handle_idr);

                h = tc_u_hash(tp);
                hlist_add_head(&tp_c->hnode, &tc_u_common_hash[h]);
        }

        tp_c->refcnt++;
        RCU_INIT_POINTER(root_ht->next, tp_c->hlist);
        rcu_assign_pointer(tp_c->hlist, root_ht);
        root_ht->tp_c = tp_c;

        rcu_assign_pointer(tp->root, root_ht);
        tp->data = tp_c;
        return 0;
}

static int u32_destroy_key(struct tcf_proto *tp, struct tc_u_knode *n,
                           bool free_pf)
{
        struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);

        tcf_exts_destroy(&n->exts);
        tcf_exts_put_net(&n->exts);
        if (ht && --ht->refcnt == 0)
                kfree(ht);
#ifdef CONFIG_CLS_U32_PERF
        if (free_pf)
                free_percpu(n->pf);
#endif
#ifdef CONFIG_CLS_U32_MARK
        if (free_pf)
                free_percpu(n->pcpu_success);
#endif
        kfree(n);
        return 0;
}

/* u32_delete_key_rcu should be called when free'ing a copied
 * version of a tc_u_knode obtained from u32_init_knode(). When
 * copies are obtained from u32_init_knode() the statistics are
 * shared between the old and new copies to allow readers to
 * continue to update the statistics during the copy. To support
 * this the u32_delete_key_rcu variant does not free the percpu
 * statistics.
 */
static void u32_delete_key_work(struct work_struct *work)
{
        struct tc_u_knode *key = container_of(to_rcu_work(work),
                                              struct tc_u_knode,
                                              rwork);
        rtnl_lock();
        u32_destroy_key(key->tp, key, false);
        rtnl_unlock();
}

/* u32_delete_key_freepf_rcu is the rcu callback variant
 * that free's the entire structure including the statistics
 * percpu variables. Only use this if the key is not a copy
 * returned by u32_init_knode(). See u32_delete_key_rcu()
 * for the variant that should be used with keys return from
 * u32_init_knode()
 */
static void u32_delete_key_freepf_work(struct work_struct *work)
{
        struct tc_u_knode *key = container_of(to_rcu_work(work),
                                              struct tc_u_knode,
                                              rwork);
        rtnl_lock();
        u32_destroy_key(key->tp, key, true);
        rtnl_unlock();
}

static int u32_delete_key(struct tcf_proto *tp, struct tc_u_knode *key)
{
        struct tc_u_knode __rcu **kp;
        struct tc_u_knode *pkp;
        struct tc_u_hnode *ht = rtnl_dereference(key->ht_up);

        if (ht) {
                kp = &ht->ht[TC_U32_HASH(key->handle)];
                for (pkp = rtnl_dereference(*kp); pkp;
                     kp = &pkp->next, pkp = rtnl_dereference(*kp)) {
                        if (pkp == key) {
                                RCU_INIT_POINTER(*kp, key->next);

                                tcf_unbind_filter(tp, &key->res);
                                idr_remove(&ht->handle_idr, key->handle);
                                tcf_exts_get_net(&key->exts);
                                tcf_queue_work(&key->rwork, u32_delete_key_freepf_work);
                                return 0;
                        }
                }
        }
        WARN_ON(1);
        return 0;
}

static void u32_clear_hw_hnode(struct tcf_proto *tp, struct tc_u_hnode *h,
                               struct netlink_ext_ack *extack)
{
        struct tcf_block *block = tp->chain->block;
        struct tc_cls_u32_offload cls_u32 = {};

        tc_cls_common_offload_init(&cls_u32.common, tp, h->flags, extack);
        cls_u32.command = TC_CLSU32_DELETE_HNODE;
        cls_u32.hnode.divisor = h->divisor;
        cls_u32.hnode.handle = h->handle;
        cls_u32.hnode.prio = h->prio;

        tc_setup_cb_call(block, NULL, TC_SETUP_CLSU32, &cls_u32, false);
}

static int u32_replace_hw_hnode(struct tcf_proto *tp, struct tc_u_hnode *h,
                                u32 flags, struct netlink_ext_ack *extack)
{
        struct tcf_block *block = tp->chain->block;
        struct tc_cls_u32_offload cls_u32 = {};
        bool skip_sw = tc_skip_sw(flags);
        bool offloaded = false;
        int err;

        tc_cls_common_offload_init(&cls_u32.common, tp, flags, extack);
        cls_u32.command = TC_CLSU32_NEW_HNODE;
        cls_u32.hnode.divisor = h->divisor;
        cls_u32.hnode.handle = h->handle;
        cls_u32.hnode.prio = h->prio;

        err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSU32, &cls_u32, skip_sw);
        if (err < 0) {
                u32_clear_hw_hnode(tp, h, NULL);
                return err;
        } else if (err > 0) {
                offloaded = true;
        }

        if (skip_sw && !offloaded)
                return -EINVAL;

        return 0;
}

static void u32_remove_hw_knode(struct tcf_proto *tp, struct tc_u_knode *n,
                                struct netlink_ext_ack *extack)
{
        struct tcf_block *block = tp->chain->block;
        struct tc_cls_u32_offload cls_u32 = {};

        tc_cls_common_offload_init(&cls_u32.common, tp, n->flags, extack);
        cls_u32.command = TC_CLSU32_DELETE_KNODE;
        cls_u32.knode.handle = n->handle;

        tc_setup_cb_call(block, NULL, TC_SETUP_CLSU32, &cls_u32, false);
        tcf_block_offload_dec(block, &n->flags);
}

static int u32_replace_hw_knode(struct tcf_proto *tp, struct tc_u_knode *n,
                                u32 flags, struct netlink_ext_ack *extack)
{
        struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
        struct tcf_block *block = tp->chain->block;
        struct tc_cls_u32_offload cls_u32 = {};
        bool skip_sw = tc_skip_sw(flags);
        int err;

        tc_cls_common_offload_init(&cls_u32.common, tp, flags, extack);
        cls_u32.command = TC_CLSU32_REPLACE_KNODE;
        cls_u32.knode.handle = n->handle;
        cls_u32.knode.fshift = n->fshift;
#ifdef CONFIG_CLS_U32_MARK
        cls_u32.knode.val = n->val;
        cls_u32.knode.mask = n->mask;
#else
        cls_u32.knode.val = 0;
        cls_u32.knode.mask = 0;
#endif
        cls_u32.knode.sel = &n->sel;
        cls_u32.knode.exts = &n->exts;
        if (n->ht_down)
                cls_u32.knode.link_handle = ht->handle;

        err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSU32, &cls_u32, skip_sw);
        if (err < 0) {
                u32_remove_hw_knode(tp, n, NULL);
                return err;
        } else if (err > 0) {
                tcf_block_offload_inc(block, &n->flags);
        }

        if (skip_sw && !(n->flags & TCA_CLS_FLAGS_IN_HW))
                return -EINVAL;

        return 0;
}

static void u32_clear_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht,
                            struct netlink_ext_ack *extack)
{
        struct tc_u_knode *n;
        unsigned int h;

        for (h = 0; h <= ht->divisor; h++) {
                while ((n = rtnl_dereference(ht->ht[h])) != NULL) {
                        RCU_INIT_POINTER(ht->ht[h],
                                         rtnl_dereference(n->next));
                        tcf_unbind_filter(tp, &n->res);
                        u32_remove_hw_knode(tp, n, extack);
                        idr_remove(&ht->handle_idr, n->handle);
                        if (tcf_exts_get_net(&n->exts))
                                tcf_queue_work(&n->rwork, u32_delete_key_freepf_work);
                        else
                                u32_destroy_key(n->tp, n, true);
                }
        }
}

static int u32_destroy_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht,
                             struct netlink_ext_ack *extack)
{
        struct tc_u_common *tp_c = tp->data;
        struct tc_u_hnode __rcu **hn;
        struct tc_u_hnode *phn;

        WARN_ON(ht->refcnt);

        u32_clear_hnode(tp, ht, extack);

        hn = &tp_c->hlist;
        for (phn = rtnl_dereference(*hn);
             phn;
             hn = &phn->next, phn = rtnl_dereference(*hn)) {
                if (phn == ht) {
                        u32_clear_hw_hnode(tp, ht, extack);
                        idr_destroy(&ht->handle_idr);
                        idr_remove(&tp_c->handle_idr, ht->handle);
                        RCU_INIT_POINTER(*hn, ht->next);
                        kfree_rcu(ht, rcu);
                        return 0;
                }
        }

        return -ENOENT;
}

static bool ht_empty(struct tc_u_hnode *ht)
{
        unsigned int h;

        for (h = 0; h <= ht->divisor; h++)
                if (rcu_access_pointer(ht->ht[h]))
                        return false;

        return true;
}

static void u32_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
{
        struct tc_u_common *tp_c = tp->data;
        struct tc_u_hnode *root_ht = rtnl_dereference(tp->root);

        WARN_ON(root_ht == NULL);

        if (root_ht && --root_ht->refcnt == 0)
                u32_destroy_hnode(tp, root_ht, extack);

        if (--tp_c->refcnt == 0) {
                struct tc_u_hnode *ht;

                hlist_del(&tp_c->hnode);

                while ((ht = rtnl_dereference(tp_c->hlist)) != NULL) {
                        u32_clear_hnode(tp, ht, extack);
                        RCU_INIT_POINTER(tp_c->hlist, ht->next);

                        /* u32_destroy_key() will later free ht for us, if it's
                         * still referenced by some knode
                         */
                        if (--ht->refcnt == 0)
                                kfree_rcu(ht, rcu);
                }

                idr_destroy(&tp_c->handle_idr);
                kfree(tp_c);
        }

        tp->data = NULL;
}

static int u32_delete(struct tcf_proto *tp, void *arg, bool *last,
                      struct netlink_ext_ack *extack)
{
        struct tc_u_hnode *ht = arg;
        struct tc_u_hnode *root_ht = rtnl_dereference(tp->root);
        struct tc_u_common *tp_c = tp->data;
        int ret = 0;

        if (ht == NULL)
                goto out;

        if (TC_U32_KEY(ht->handle)) {
                u32_remove_hw_knode(tp, (struct tc_u_knode *)ht, extack);
                ret = u32_delete_key(tp, (struct tc_u_knode *)ht);
                goto out;
        }

        if (root_ht == ht) {
                NL_SET_ERR_MSG_MOD(extack, "Not allowed to delete root node");
                return -EINVAL;
        }

        if (ht->refcnt == 1) {
                ht->refcnt--;
                u32_destroy_hnode(tp, ht, extack);
        } else {
                NL_SET_ERR_MSG_MOD(extack, "Can not delete in-use filter");
                return -EBUSY;
        }

out:
        *last = true;
        if (root_ht) {
                if (root_ht->refcnt > 1) {
                        *last = false;
                        goto ret;
                }
                if (root_ht->refcnt == 1) {
                        if (!ht_empty(root_ht)) {
                                *last = false;
                                goto ret;
                        }
                }
        }

        if (tp_c->refcnt > 1) {
                *last = false;
                goto ret;
        }

        if (tp_c->refcnt == 1) {
                struct tc_u_hnode *ht;

                for (ht = rtnl_dereference(tp_c->hlist);
                     ht;
                     ht = rtnl_dereference(ht->next))
                        if (!ht_empty(ht)) {
                                *last = false;
                                break;
                        }
        }

ret:
        return ret;
}

static u32 gen_new_kid(struct tc_u_hnode *ht, u32 htid)
{
        u32 index = htid | 0x800;
        u32 max = htid | 0xFFF;

        if (idr_alloc_u32(&ht->handle_idr, NULL, &index, max, GFP_KERNEL)) {
                index = htid + 1;
                if (idr_alloc_u32(&ht->handle_idr, NULL, &index, max,
                                 GFP_KERNEL))
                        index = max;
        }

        return index;
}

static const struct nla_policy u32_policy[TCA_U32_MAX + 1] = {
        [TCA_U32_CLASSID]       = { .type = NLA_U32 },
        [TCA_U32_HASH]          = { .type = NLA_U32 },
        [TCA_U32_LINK]          = { .type = NLA_U32 },
        [TCA_U32_DIVISOR]       = { .type = NLA_U32 },
        [TCA_U32_SEL]           = { .len = sizeof(struct tc_u32_sel) },
        [TCA_U32_INDEV]         = { .type = NLA_STRING, .len = IFNAMSIZ },
        [TCA_U32_MARK]          = { .len = sizeof(struct tc_u32_mark) },
        [TCA_U32_FLAGS]         = { .type = NLA_U32 },
};

static int u32_set_parms(struct net *net, struct tcf_proto *tp,
                         unsigned long base, struct tc_u_hnode *ht,
                         struct tc_u_knode *n, struct nlattr **tb,
                         struct nlattr *est, bool ovr,
                         struct netlink_ext_ack *extack)
{
        int err;

        err = tcf_exts_validate(net, tp, tb, est, &n->exts, ovr, extack);
        if (err < 0)
                return err;

        if (tb[TCA_U32_LINK]) {
                u32 handle = nla_get_u32(tb[TCA_U32_LINK]);
                struct tc_u_hnode *ht_down = NULL, *ht_old;

                if (TC_U32_KEY(handle)) {
                        NL_SET_ERR_MSG_MOD(extack, "u32 Link handle must be a hash table");
                        return -EINVAL;
                }

                if (handle) {
                        ht_down = u32_lookup_ht(ht->tp_c, handle);

                        if (!ht_down) {
                                NL_SET_ERR_MSG_MOD(extack, "Link hash table not found");
                                return -EINVAL;
                        }
                        ht_down->refcnt++;
                }

                ht_old = rtnl_dereference(n->ht_down);
                rcu_assign_pointer(n->ht_down, ht_down);

                if (ht_old)
                        ht_old->refcnt--;
        }
        if (tb[TCA_U32_CLASSID]) {
                n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
                tcf_bind_filter(tp, &n->res, base);
        }

#ifdef CONFIG_NET_CLS_IND
        if (tb[TCA_U32_INDEV]) {
                int ret;
                ret = tcf_change_indev(net, tb[TCA_U32_INDEV], extack);
                if (ret < 0)
                        return -EINVAL;
                n->ifindex = ret;
        }
#endif
        return 0;
}

static void u32_replace_knode(struct tcf_proto *tp, struct tc_u_common *tp_c,
                              struct tc_u_knode *n)
{
        struct tc_u_knode __rcu **ins;
        struct tc_u_knode *pins;
        struct tc_u_hnode *ht;

        if (TC_U32_HTID(n->handle) == TC_U32_ROOT)
                ht = rtnl_dereference(tp->root);
        else
                ht = u32_lookup_ht(tp_c, TC_U32_HTID(n->handle));

        ins = &ht->ht[TC_U32_HASH(n->handle)];

        /* The node must always exist for it to be replaced if this is not the
         * case then something went very wrong elsewhere.
         */
        for (pins = rtnl_dereference(*ins); ;
             ins = &pins->next, pins = rtnl_dereference(*ins))
                if (pins->handle == n->handle)
                        break;

        idr_replace(&ht->handle_idr, n, n->handle);
        RCU_INIT_POINTER(n->next, pins->next);
        rcu_assign_pointer(*ins, n);
}

static struct tc_u_knode *u32_init_knode(struct tcf_proto *tp,
                                         struct tc_u_knode *n)
{
        struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
        struct tc_u32_sel *s = &n->sel;
        struct tc_u_knode *new;

        new = kzalloc(sizeof(*n) + s->nkeys*sizeof(struct tc_u32_key),
                      GFP_KERNEL);

        if (!new)
                return NULL;

        RCU_INIT_POINTER(new->next, n->next);
        new->handle = n->handle;
        RCU_INIT_POINTER(new->ht_up, n->ht_up);

#ifdef CONFIG_NET_CLS_IND
        new->ifindex = n->ifindex;
#endif
        new->fshift = n->fshift;
        new->res = n->res;
        new->flags = n->flags;
        RCU_INIT_POINTER(new->ht_down, ht);

        /* bump reference count as long as we hold pointer to structure */
        if (ht)
                ht->refcnt++;

#ifdef CONFIG_CLS_U32_PERF
        /* Statistics may be incremented by readers during update
         * so we must keep them in tact. When the node is later destroyed
         * a special destroy call must be made to not free the pf memory.
         */
        new->pf = n->pf;
#endif

#ifdef CONFIG_CLS_U32_MARK
        new->val = n->val;
        new->mask = n->mask;
        /* Similarly success statistics must be moved as pointers */
        new->pcpu_success = n->pcpu_success;
#endif
        new->tp = tp;
        memcpy(&new->sel, s, sizeof(*s) + s->nkeys*sizeof(struct tc_u32_key));

        if (tcf_exts_init(&new->exts, TCA_U32_ACT, TCA_U32_POLICE)) {
                kfree(new);
                return NULL;
        }

        return new;
}

static int u32_change(struct net *net, struct sk_buff *in_skb,
                      struct tcf_proto *tp, unsigned long base, u32 handle,
                      struct nlattr **tca, void **arg, bool ovr,
                      struct netlink_ext_ack *extack)
{
        struct tc_u_common *tp_c = tp->data;
        struct tc_u_hnode *ht;
        struct tc_u_knode *n;
        struct tc_u32_sel *s;
        struct nlattr *opt = tca[TCA_OPTIONS];
        struct nlattr *tb[TCA_U32_MAX + 1];
        u32 htid, flags = 0;
        int err;
#ifdef CONFIG_CLS_U32_PERF
        size_t size;
#endif

        if (!opt) {
                if (handle) {
                        NL_SET_ERR_MSG_MOD(extack, "Filter handle requires options");
                        return -EINVAL;
                } else {
                        return 0;
                }
        }

        err = nla_parse_nested(tb, TCA_U32_MAX, opt, u32_policy, extack);
        if (err < 0)
                return err;

        if (tb[TCA_U32_FLAGS]) {
                flags = nla_get_u32(tb[TCA_U32_FLAGS]);
                if (!tc_flags_valid(flags)) {
                        NL_SET_ERR_MSG_MOD(extack, "Invalid filter flags");
                        return -EINVAL;
                }
        }

        n = *arg;
        if (n) {
                struct tc_u_knode *new;

                if (TC_U32_KEY(n->handle) == 0) {
                        NL_SET_ERR_MSG_MOD(extack, "Key node id cannot be zero");
                        return -EINVAL;
                }

                if ((n->flags ^ flags) &
                    ~(TCA_CLS_FLAGS_IN_HW | TCA_CLS_FLAGS_NOT_IN_HW)) {
                        NL_SET_ERR_MSG_MOD(extack, "Key node flags do not match passed flags");
                        return -EINVAL;
                }

                new = u32_init_knode(tp, n);
                if (!new)
                        return -ENOMEM;

                err = u32_set_parms(net, tp, base,
                                    rtnl_dereference(n->ht_up), new, tb,
                                    tca[TCA_RATE], ovr, extack);

                if (err) {
                        u32_destroy_key(tp, new, false);
                        return err;
                }

                err = u32_replace_hw_knode(tp, new, flags, extack);
                if (err) {
                        u32_destroy_key(tp, new, false);
                        return err;
                }

                if (!tc_in_hw(new->flags))
                        new->flags |= TCA_CLS_FLAGS_NOT_IN_HW;

                u32_replace_knode(tp, tp_c, new);
                tcf_unbind_filter(tp, &n->res);
                tcf_exts_get_net(&n->exts);
                tcf_queue_work(&n->rwork, u32_delete_key_work);
                return 0;
        }

        if (tb[TCA_U32_DIVISOR]) {
                unsigned int divisor = nla_get_u32(tb[TCA_U32_DIVISOR]);

                if (--divisor > 0x100) {
                        NL_SET_ERR_MSG_MOD(extack, "Exceeded maximum 256 hash buckets");
                        return -EINVAL;
                }
                if (TC_U32_KEY(handle)) {
                        NL_SET_ERR_MSG_MOD(extack, "Divisor can only be used on a hash table");
                        return -EINVAL;
                }
                ht = kzalloc(sizeof(*ht) + divisor*sizeof(void *), GFP_KERNEL);
                if (ht == NULL)
                        return -ENOBUFS;
                if (handle == 0) {
                        handle = gen_new_htid(tp->data, ht);
                        if (handle == 0) {
                                kfree(ht);
                                return -ENOMEM;
                        }
                } else {
                        err = idr_alloc_u32(&tp_c->handle_idr, ht, &handle,
                                            handle, GFP_KERNEL);
                        if (err) {
                                kfree(ht);
                                return err;
                        }
                }
                ht->tp_c = tp_c;
                ht->refcnt = 1;
                ht->divisor = divisor;
                ht->handle = handle;
                ht->prio = tp->prio;
                idr_init(&ht->handle_idr);
                ht->flags = flags;

                err = u32_replace_hw_hnode(tp, ht, flags, extack);
                if (err) {
                        idr_remove(&tp_c->handle_idr, handle);
                        kfree(ht);
                        return err;
                }

                RCU_INIT_POINTER(ht->next, tp_c->hlist);
                rcu_assign_pointer(tp_c->hlist, ht);
                *arg = ht;

                return 0;
        }

        if (tb[TCA_U32_HASH]) {
                htid = nla_get_u32(tb[TCA_U32_HASH]);
                if (TC_U32_HTID(htid) == TC_U32_ROOT) {
                        ht = rtnl_dereference(tp->root);
                        htid = ht->handle;
                } else {
                        ht = u32_lookup_ht(tp->data, TC_U32_HTID(htid));
                        if (!ht) {
                                NL_SET_ERR_MSG_MOD(extack, "Specified hash table not found");
                                return -EINVAL;
                        }
                }
        } else {
                ht = rtnl_dereference(tp->root);
                htid = ht->handle;
        }

        if (ht->divisor < TC_U32_HASH(htid)) {
                NL_SET_ERR_MSG_MOD(extack, "Specified hash table buckets exceed configured value");
                return -EINVAL;
        }

        if (handle) {
                if (TC_U32_HTID(handle) && TC_U32_HTID(handle ^ htid)) {
                        NL_SET_ERR_MSG_MOD(extack, "Handle specified hash table address mismatch");
                        return -EINVAL;
                }
                handle = htid | TC_U32_NODE(handle);
                err = idr_alloc_u32(&ht->handle_idr, NULL, &handle, handle,
                                    GFP_KERNEL);
                if (err)
                        return err;
        } else
                handle = gen_new_kid(ht, htid);

        if (tb[TCA_U32_SEL] == NULL) {
                NL_SET_ERR_MSG_MOD(extack, "Selector not specified");
                err = -EINVAL;
                goto erridr;
        }

        s = nla_data(tb[TCA_U32_SEL]);

        n = kzalloc(sizeof(*n) + s->nkeys*sizeof(struct tc_u32_key), GFP_KERNEL);
        if (n == NULL) {
                err = -ENOBUFS;
                goto erridr;
        }

#ifdef CONFIG_CLS_U32_PERF
        size = sizeof(struct tc_u32_pcnt) + s->nkeys * sizeof(u64);
        n->pf = __alloc_percpu(size, __alignof__(struct tc_u32_pcnt));
        if (!n->pf) {
                err = -ENOBUFS;
                goto errfree;
        }
#endif

        memcpy(&n->sel, s, sizeof(*s) + s->nkeys*sizeof(struct tc_u32_key));
        RCU_INIT_POINTER(n->ht_up, ht);
        n->handle = handle;
        n->fshift = s->hmask ? ffs(ntohl(s->hmask)) - 1 : 0;
        n->flags = flags;
        n->tp = tp;

        err = tcf_exts_init(&n->exts, TCA_U32_ACT, TCA_U32_POLICE);
        if (err < 0)
                goto errout;

#ifdef CONFIG_CLS_U32_MARK
        n->pcpu_success = alloc_percpu(u32);
        if (!n->pcpu_success) {
                err = -ENOMEM;
                goto errout;
        }

        if (tb[TCA_U32_MARK]) {
                struct tc_u32_mark *mark;

                mark = nla_data(tb[TCA_U32_MARK]);
                n->val = mark->val;
                n->mask = mark->mask;
        }
#endif

        err = u32_set_parms(net, tp, base, ht, n, tb, tca[TCA_RATE], ovr,
                            extack);
        if (err == 0) {
                struct tc_u_knode __rcu **ins;
                struct tc_u_knode *pins;

                err = u32_replace_hw_knode(tp, n, flags, extack);
                if (err)
                        goto errhw;

                if (!tc_in_hw(n->flags))
                        n->flags |= TCA_CLS_FLAGS_NOT_IN_HW;

                ins = &ht->ht[TC_U32_HASH(handle)];
                for (pins = rtnl_dereference(*ins); pins;
                     ins = &pins->next, pins = rtnl_dereference(*ins))
                        if (TC_U32_NODE(handle) < TC_U32_NODE(pins->handle))
                                break;

                RCU_INIT_POINTER(n->next, pins);
                rcu_assign_pointer(*ins, n);
                *arg = n;
                return 0;
        }

errhw:
#ifdef CONFIG_CLS_U32_MARK
        free_percpu(n->pcpu_success);
#endif

errout:
        tcf_exts_destroy(&n->exts);
#ifdef CONFIG_CLS_U32_PERF
errfree:
        free_percpu(n->pf);
#endif
        kfree(n);
erridr:
        idr_remove(&ht->handle_idr, handle);
        return err;
}

static void u32_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
        struct tc_u_common *tp_c = tp->data;
        struct tc_u_hnode *ht;
        struct tc_u_knode *n;
        unsigned int h;

        if (arg->stop)
                return;

        for (ht = rtnl_dereference(tp_c->hlist);
             ht;
             ht = rtnl_dereference(ht->next)) {
                if (ht->prio != tp->prio)
                        continue;
                if (arg->count >= arg->skip) {
                        if (arg->fn(tp, ht, arg) < 0) {
                                arg->stop = 1;
                                return;
                        }
                }
                arg->count++;
                for (h = 0; h <= ht->divisor; h++) {
                        for (n = rtnl_dereference(ht->ht[h]);
                             n;
                             n = rtnl_dereference(n->next)) {
                                if (arg->count < arg->skip) {
                                        arg->count++;
                                        continue;
                                }
                                if (arg->fn(tp, n, arg) < 0) {
                                        arg->stop = 1;
                                        return;
                                }
                                arg->count++;
                        }
                }
        }
}

static void u32_bind_class(void *fh, u32 classid, unsigned long cl)
{
        struct tc_u_knode *n = fh;

        if (n && n->res.classid == classid)
                n->res.class = cl;
}

static int u32_dump(struct net *net, struct tcf_proto *tp, void *fh,
                    struct sk_buff *skb, struct tcmsg *t)
{
        struct tc_u_knode *n = fh;
        struct tc_u_hnode *ht_up, *ht_down;
        struct nlattr *nest;

        if (n == NULL)
                return skb->len;

        t->tcm_handle = n->handle;

        nest = nla_nest_start(skb, TCA_OPTIONS);
        if (nest == NULL)
                goto nla_put_failure;

        if (TC_U32_KEY(n->handle) == 0) {
                struct tc_u_hnode *ht = fh;
                u32 divisor = ht->divisor + 1;

                if (nla_put_u32(skb, TCA_U32_DIVISOR, divisor))
                        goto nla_put_failure;
        } else {
#ifdef CONFIG_CLS_U32_PERF
                struct tc_u32_pcnt *gpf;
                int cpu;
#endif

                if (nla_put(skb, TCA_U32_SEL,
                            sizeof(n->sel) + n->sel.nkeys*sizeof(struct tc_u32_key),
                            &n->sel))
                        goto nla_put_failure;

                ht_up = rtnl_dereference(n->ht_up);
                if (ht_up) {
                        u32 htid = n->handle & 0xFFFFF000;
                        if (nla_put_u32(skb, TCA_U32_HASH, htid))
                                goto nla_put_failure;
                }
                if (n->res.classid &&
                    nla_put_u32(skb, TCA_U32_CLASSID, n->res.classid))
                        goto nla_put_failure;

                ht_down = rtnl_dereference(n->ht_down);
                if (ht_down &&
                    nla_put_u32(skb, TCA_U32_LINK, ht_down->handle))
                        goto nla_put_failure;

                if (n->flags && nla_put_u32(skb, TCA_U32_FLAGS, n->flags))
                        goto nla_put_failure;

#ifdef CONFIG_CLS_U32_MARK
                if ((n->val || n->mask)) {
                        struct tc_u32_mark mark = {.val = n->val,
                                                   .mask = n->mask,
                                                   .success = 0};
                        int cpum;

                        for_each_possible_cpu(cpum) {
                                __u32 cnt = *per_cpu_ptr(n->pcpu_success, cpum);

                                mark.success += cnt;
                        }

                        if (nla_put(skb, TCA_U32_MARK, sizeof(mark), &mark))
                                goto nla_put_failure;
                }
#endif

                if (tcf_exts_dump(skb, &n->exts) < 0)
                        goto nla_put_failure;

#ifdef CONFIG_NET_CLS_IND
                if (n->ifindex) {
                        struct net_device *dev;
                        dev = __dev_get_by_index(net, n->ifindex);
                        if (dev && nla_put_string(skb, TCA_U32_INDEV, dev->name))
                                goto nla_put_failure;
                }
#endif
#ifdef CONFIG_CLS_U32_PERF
                gpf = kzalloc(sizeof(struct tc_u32_pcnt) +
                              n->sel.nkeys * sizeof(u64),
                              GFP_KERNEL);
                if (!gpf)
                        goto nla_put_failure;

                for_each_possible_cpu(cpu) {
                        int i;
                        struct tc_u32_pcnt *pf = per_cpu_ptr(n->pf, cpu);

                        gpf->rcnt += pf->rcnt;
                        gpf->rhit += pf->rhit;
                        for (i = 0; i < n->sel.nkeys; i++)
                                gpf->kcnts[i] += pf->kcnts[i];
                }

                if (nla_put_64bit(skb, TCA_U32_PCNT,
                                  sizeof(struct tc_u32_pcnt) +
                                  n->sel.nkeys * sizeof(u64),
                                  gpf, TCA_U32_PAD)) {
                        kfree(gpf);
                        goto nla_put_failure;
                }
                kfree(gpf);
#endif
        }

        nla_nest_end(skb, nest);

        if (TC_U32_KEY(n->handle))
                if (tcf_exts_dump_stats(skb, &n->exts) < 0)
                        goto nla_put_failure;
        return skb->len;

nla_put_failure:
        nla_nest_cancel(skb, nest);
        return -1;
}

static struct tcf_proto_ops cls_u32_ops __read_mostly = {
        .kind           =       "u32",
        .classify       =       u32_classify,
        .init           =       u32_init,
        .destroy        =       u32_destroy,
        .get            =       u32_get,
        .change         =       u32_change,
        .delete         =       u32_delete,
        .walk           =       u32_walk,
        .dump           =       u32_dump,
        .bind_class     =       u32_bind_class,
        .owner          =       THIS_MODULE,
};

static int __init init_u32(void)
{
        int i, ret;

        pr_info("u32 classifier\n");
#ifdef CONFIG_CLS_U32_PERF
        pr_info("    Performance counters on\n");
#endif
#ifdef CONFIG_NET_CLS_IND
        pr_info("    input device check on\n");
#endif
#ifdef CONFIG_NET_CLS_ACT
        pr_info("    Actions configured\n");
#endif
        tc_u_common_hash = kvmalloc_array(U32_HASH_SIZE,
                                          sizeof(struct hlist_head),
                                          GFP_KERNEL);
        if (!tc_u_common_hash)
                return -ENOMEM;

        for (i = 0; i < U32_HASH_SIZE; i++)
                INIT_HLIST_HEAD(&tc_u_common_hash[i]);

        ret = register_tcf_proto_ops(&cls_u32_ops);
        if (ret)
                kvfree(tc_u_common_hash);
        return ret;
}

static void __exit exit_u32(void)
{
        unregister_tcf_proto_ops(&cls_u32_ops);
        kvfree(tc_u_common_hash);
}

module_init(init_u32)
module_exit(exit_u32)
MODULE_LICENSE("GPL");