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root/net/sched/cls_u32.c

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DEFINITIONS

This source file includes following definitions.
  1. u32_hash_fold
  2. u32_classify
  3. u32_lookup_ht
  4. u32_lookup_key
  5. u32_get
  6. u32_put
  7. gen_new_htid
  8. u32_init
  9. u32_destroy_key
  10. u32_delete_key
  11. u32_clear_hnode
  12. u32_destroy_hnode
  13. u32_destroy
  14. u32_delete
  15. gen_new_kid
  16. u32_set_parms
  17. u32_change
  18. u32_walk
  19. u32_dump
  20. init_u32
  21. exit_u32

/*
 * 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/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <net/netlink.h>
#include <net/act_api.h>
#include <net/pkt_cls.h>

struct tc_u_knode
{
        struct tc_u_knode       *next;
        u32                     handle;
        struct tc_u_hnode       *ht_up;
        struct tcf_exts         exts;
#ifdef CONFIG_NET_CLS_IND
        char                     indev[IFNAMSIZ];
#endif
        u8                      fshift;
        struct tcf_result       res;
        struct tc_u_hnode       *ht_down;
#ifdef CONFIG_CLS_U32_PERF
        struct tc_u32_pcnt      *pf;
#endif
#ifdef CONFIG_CLS_U32_MARK
        struct tc_u32_mark      mark;
#endif
        struct tc_u32_sel       sel;
};

struct tc_u_hnode
{
        struct tc_u_hnode       *next;
        u32                     handle;
        u32                     prio;
        struct tc_u_common      *tp_c;
        int                     refcnt;
        unsigned                divisor;
        struct tc_u_knode       *ht[1];
};

struct tc_u_common
{
        struct tc_u_hnode       *hlist;
        struct Qdisc            *q;
        int                     refcnt;
        u32                     hgenerator;
};

static const struct tcf_ext_map u32_ext_map = {
        .action = TCA_U32_ACT,
        .police = TCA_U32_POLICE
};

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

        return h;
}

static int u32_classify(struct sk_buff *skb, struct tcf_proto *tp, struct tcf_result *res)
{
        struct {
                struct tc_u_knode *knode;
                u8                *ptr;
        } stack[TC_U32_MAXDEPTH];

        struct tc_u_hnode *ht = (struct tc_u_hnode*)tp->root;
        u8 *ptr = skb_network_header(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 = ht->ht[sel];

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

#ifdef CONFIG_CLS_U32_PERF
                n->pf->rcnt +=1;
                j = 0;
#endif

#ifdef CONFIG_CLS_U32_MARK
                if ((skb->mark & n->mark.mask) != n->mark.val) {
                        n = n->next;
                        goto next_knode;
                } else {
                        n->mark.success++;
                }
#endif

                for (i = n->sel.nkeys; i>0; i--, key++) {

                        if ((*(__be32*)(ptr+key->off+(off2&key->offmask))^key->val)&key->mask) {
                                n = n->next;
                                goto next_knode;
                        }
#ifdef CONFIG_CLS_U32_PERF
                        n->pf->kcnts[j] +=1;
                        j++;
#endif
                }
                if (n->ht_down == NULL) {
check_terminal:
                        if (n->sel.flags&TC_U32_TERMINAL) {

                                *res = n->res;
#ifdef CONFIG_NET_CLS_IND
                                if (!tcf_match_indev(skb, n->indev)) {
                                        n = n->next;
                                        goto next_knode;
                                }
#endif
#ifdef CONFIG_CLS_U32_PERF
                                n->pf->rhit +=1;
#endif
                                r = tcf_exts_exec(skb, &n->exts, res);
                                if (r < 0) {
                                        n = n->next;
                                        goto next_knode;
                                }

                                return r;
                        }
                        n = n->next;
                        goto next_knode;
                }

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

                ht = n->ht_down;
                sel = 0;
                if (ht->divisor)
                        sel = ht->divisor&u32_hash_fold(*(__be32*)(ptr+n->sel.hoff), &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)
                                off2 += ntohs(n->sel.offmask & *(__be16*)(ptr+n->sel.offoff)) >>n->sel.offshift;
                        off2 &= ~3;
                }
                if (n->sel.flags&TC_U32_EAT) {
                        ptr += off2;
                        off2 = 0;
                }

                if (ptr < skb_tail_pointer(skb))
                        goto next_ht;
        }

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

deadloop:
        if (net_ratelimit())
                printk("cls_u32: dead loop\n");
        return -1;
}

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

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

        return ht;
}

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

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

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


static unsigned long 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 = tp->root;
        else
                ht = u32_lookup_ht(tp_c, TC_U32_HTID(handle));

        if (!ht)
                return 0;

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

        return (unsigned long)u32_lookup_key(ht, handle);
}

static void u32_put(struct tcf_proto *tp, unsigned long f)
{
}

static u32 gen_new_htid(struct tc_u_common *tp_c)
{
        int i = 0x800;

        do {
                if (++tp_c->hgenerator == 0x7FF)
                        tp_c->hgenerator = 1;
        } while (--i>0 && u32_lookup_ht(tp_c, (tp_c->hgenerator|0x800)<<20));

        return i > 0 ? (tp_c->hgenerator|0x800)<<20 : 0;
}

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

        tp_c = tp->q->u32_node;

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

        root_ht->divisor = 0;
        root_ht->refcnt++;
        root_ht->handle = tp_c ? gen_new_htid(tp_c) : 0x80000000;
        root_ht->prio = tp->prio;

        if (tp_c == NULL) {
                tp_c = kzalloc(sizeof(*tp_c), GFP_KERNEL);
                if (tp_c == NULL) {
                        kfree(root_ht);
                        return -ENOBUFS;
                }
                tp_c->q = tp->q;
                tp->q->u32_node = tp_c;
        }

        tp_c->refcnt++;
        root_ht->next = tp_c->hlist;
        tp_c->hlist = root_ht;
        root_ht->tp_c = tp_c;

        tp->root = root_ht;
        tp->data = tp_c;
        return 0;
}

static int u32_destroy_key(struct tcf_proto *tp, struct tc_u_knode *n)
{
        tcf_unbind_filter(tp, &n->res);
        tcf_exts_destroy(tp, &n->exts);
        if (n->ht_down)
                n->ht_down->refcnt--;
#ifdef CONFIG_CLS_U32_PERF
        kfree(n->pf);
#endif
        kfree(n);
        return 0;
}

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

        if (ht) {
                for (kp = &ht->ht[TC_U32_HASH(key->handle)]; *kp; kp = &(*kp)->next) {
                        if (*kp == key) {
                                tcf_tree_lock(tp);
                                *kp = key->next;
                                tcf_tree_unlock(tp);

                                u32_destroy_key(tp, key);
                                return 0;
                        }
                }
        }
        WARN_ON(1);
        return 0;
}

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

        for (h=0; h<=ht->divisor; h++) {
                while ((n = ht->ht[h]) != NULL) {
                        ht->ht[h] = n->next;

                        u32_destroy_key(tp, n);
                }
        }
}

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

        WARN_ON(ht->refcnt);

        u32_clear_hnode(tp, ht);

        for (hn = &tp_c->hlist; *hn; hn = &(*hn)->next) {
                if (*hn == ht) {
                        *hn = ht->next;
                        kfree(ht);
                        return 0;
                }
        }

        WARN_ON(1);
        return -ENOENT;
}

static void u32_destroy(struct tcf_proto *tp)
{
        struct tc_u_common *tp_c = tp->data;
        struct tc_u_hnode *root_ht = xchg(&tp->root, NULL);

        WARN_ON(root_ht == NULL);

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

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

                tp->q->u32_node = NULL;

                for (ht = tp_c->hlist; ht; ht = ht->next) {
                        ht->refcnt--;
                        u32_clear_hnode(tp, ht);
                }

                while ((ht = tp_c->hlist) != NULL) {
                        tp_c->hlist = ht->next;

                        WARN_ON(ht->refcnt != 0);

                        kfree(ht);
                }

                kfree(tp_c);
        }

        tp->data = NULL;
}

static int u32_delete(struct tcf_proto *tp, unsigned long arg)
{
        struct tc_u_hnode *ht = (struct tc_u_hnode*)arg;

        if (ht == NULL)
                return 0;

        if (TC_U32_KEY(ht->handle))
                return u32_delete_key(tp, (struct tc_u_knode*)ht);

        if (tp->root == ht)
                return -EINVAL;

        if (ht->refcnt == 1) {
                ht->refcnt--;
                u32_destroy_hnode(tp, ht);
        } else {
                return -EBUSY;
        }

        return 0;
}

static u32 gen_new_kid(struct tc_u_hnode *ht, u32 handle)
{
        struct tc_u_knode *n;
        unsigned i = 0x7FF;

        for (n=ht->ht[TC_U32_HASH(handle)]; n; n = n->next)
                if (i < TC_U32_NODE(n->handle))
                        i = TC_U32_NODE(n->handle);
        i++;

        return handle|(i>0xFFF ? 0xFFF : i);
}

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) },
};

static int u32_set_parms(struct tcf_proto *tp, unsigned long base,
                         struct tc_u_hnode *ht,
                         struct tc_u_knode *n, struct nlattr **tb,
                         struct nlattr *est)
{
        int err;
        struct tcf_exts e;

        err = tcf_exts_validate(tp, tb, est, &e, &u32_ext_map);
        if (err < 0)
                return err;

        err = -EINVAL;
        if (tb[TCA_U32_LINK]) {
                u32 handle = nla_get_u32(tb[TCA_U32_LINK]);
                struct tc_u_hnode *ht_down = NULL;

                if (TC_U32_KEY(handle))
                        goto errout;

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

                        if (ht_down == NULL)
                                goto errout;
                        ht_down->refcnt++;
                }

                tcf_tree_lock(tp);
                ht_down = xchg(&n->ht_down, ht_down);
                tcf_tree_unlock(tp);

                if (ht_down)
                        ht_down->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]) {
                err = tcf_change_indev(tp, n->indev, tb[TCA_U32_INDEV]);
                if (err < 0)
                        goto errout;
        }
#endif
        tcf_exts_change(tp, &n->exts, &e);

        return 0;
errout:
        tcf_exts_destroy(tp, &e);
        return err;
}

static int u32_change(struct tcf_proto *tp, unsigned long base, u32 handle,
                      struct nlattr **tca,
                      unsigned long *arg)
{
        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;
        int err;

        if (opt == NULL)
                return handle ? -EINVAL : 0;

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

        if ((n = (struct tc_u_knode*)*arg) != NULL) {
                if (TC_U32_KEY(n->handle) == 0)
                        return -EINVAL;

                return u32_set_parms(tp, base, n->ht_up, n, tb, tca[TCA_RATE]);
        }

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

                if (--divisor > 0x100)
                        return -EINVAL;
                if (TC_U32_KEY(handle))
                        return -EINVAL;
                if (handle == 0) {
                        handle = gen_new_htid(tp->data);
                        if (handle == 0)
                                return -ENOMEM;
                }
                ht = kzalloc(sizeof(*ht) + divisor*sizeof(void*), GFP_KERNEL);
                if (ht == NULL)
                        return -ENOBUFS;
                ht->tp_c = tp_c;
                ht->refcnt = 1;
                ht->divisor = divisor;
                ht->handle = handle;
                ht->prio = tp->prio;
                ht->next = tp_c->hlist;
                tp_c->hlist = ht;
                *arg = (unsigned long)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 = tp->root;
                        htid = ht->handle;
                } else {
                        ht = u32_lookup_ht(tp->data, TC_U32_HTID(htid));
                        if (ht == NULL)
                                return -EINVAL;
                }
        } else {
                ht = tp->root;
                htid = ht->handle;
        }

        if (ht->divisor < TC_U32_HASH(htid))
                return -EINVAL;

        if (handle) {
                if (TC_U32_HTID(handle) && TC_U32_HTID(handle^htid))
                        return -EINVAL;
                handle = htid | TC_U32_NODE(handle);
        } else
                handle = gen_new_kid(ht, htid);

        if (tb[TCA_U32_SEL] == NULL)
                return -EINVAL;

        s = nla_data(tb[TCA_U32_SEL]);

        n = kzalloc(sizeof(*n) + s->nkeys*sizeof(struct tc_u32_key), GFP_KERNEL);
        if (n == NULL)
                return -ENOBUFS;

#ifdef CONFIG_CLS_U32_PERF
        n->pf = kzalloc(sizeof(struct tc_u32_pcnt) + s->nkeys*sizeof(u64), GFP_KERNEL);
        if (n->pf == NULL) {
                kfree(n);
                return -ENOBUFS;
        }
#endif

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

#ifdef CONFIG_CLS_U32_MARK
        if (tb[TCA_U32_MARK]) {
                struct tc_u32_mark *mark;

                mark = nla_data(tb[TCA_U32_MARK]);
                memcpy(&n->mark, mark, sizeof(struct tc_u32_mark));
                n->mark.success = 0;
        }
#endif

        err = u32_set_parms(tp, base, ht, n, tb, tca[TCA_RATE]);
        if (err == 0) {
                struct tc_u_knode **ins;
                for (ins = &ht->ht[TC_U32_HASH(handle)]; *ins; ins = &(*ins)->next)
                        if (TC_U32_NODE(handle) < TC_U32_NODE((*ins)->handle))
                                break;

                n->next = *ins;
                wmb();
                *ins = n;

                *arg = (unsigned long)n;
                return 0;
        }
#ifdef CONFIG_CLS_U32_PERF
        kfree(n->pf);
#endif
        kfree(n);
        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 h;

        if (arg->stop)
                return;

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

static int u32_dump(struct tcf_proto *tp, unsigned long fh,
                     struct sk_buff *skb, struct tcmsg *t)
{
        struct tc_u_knode *n = (struct tc_u_knode*)fh;
        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 = (struct tc_u_hnode*)fh;
                u32 divisor = ht->divisor+1;
                NLA_PUT_U32(skb, TCA_U32_DIVISOR, divisor);
        } else {
                NLA_PUT(skb, TCA_U32_SEL,
                        sizeof(n->sel) + n->sel.nkeys*sizeof(struct tc_u32_key),
                        &n->sel);
                if (n->ht_up) {
                        u32 htid = n->handle & 0xFFFFF000;
                        NLA_PUT_U32(skb, TCA_U32_HASH, htid);
                }
                if (n->res.classid)
                        NLA_PUT_U32(skb, TCA_U32_CLASSID, n->res.classid);
                if (n->ht_down)
                        NLA_PUT_U32(skb, TCA_U32_LINK, n->ht_down->handle);

#ifdef CONFIG_CLS_U32_MARK
                if (n->mark.val || n->mark.mask)
                        NLA_PUT(skb, TCA_U32_MARK, sizeof(n->mark), &n->mark);
#endif

                if (tcf_exts_dump(skb, &n->exts, &u32_ext_map) < 0)
                        goto nla_put_failure;

#ifdef CONFIG_NET_CLS_IND
                if(strlen(n->indev))
                        NLA_PUT_STRING(skb, TCA_U32_INDEV, n->indev);
#endif
#ifdef CONFIG_CLS_U32_PERF
                NLA_PUT(skb, TCA_U32_PCNT,
                sizeof(struct tc_u32_pcnt) + n->sel.nkeys*sizeof(u64),
                        n->pf);
#endif
        }

        nla_nest_end(skb, nest);

        if (TC_U32_KEY(n->handle))
                if (tcf_exts_dump_stats(skb, &n->exts, &u32_ext_map) < 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,
        .put            =       u32_put,
        .change         =       u32_change,
        .delete         =       u32_delete,
        .walk           =       u32_walk,
        .dump           =       u32_dump,
        .owner          =       THIS_MODULE,
};

static int __init init_u32(void)
{
        printk("u32 classifier\n");
#ifdef CONFIG_CLS_U32_PERF
        printk("    Performance counters on\n");
#endif
#ifdef CONFIG_NET_CLS_IND
        printk("    input device check on \n");
#endif
#ifdef CONFIG_NET_CLS_ACT
        printk("    Actions configured \n");
#endif
        return register_tcf_proto_ops(&cls_u32_ops);
}

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

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

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