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root/net/sched/act_pedit.c

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DEFINITIONS

This source file includes following definitions.
  1. tcf_pedit_init
  2. tcf_pedit_cleanup
  3. tcf_pedit
  4. tcf_pedit_dump
  5. pedit_init_module
  6. pedit_cleanup_module

/*
 * net/sched/pedit.c    Generic packet editor
 *
 *              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:     Jamal Hadi Salim (2002-4)
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/module.h>
#include <linux/init.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <linux/tc_act/tc_pedit.h>
#include <net/tc_act/tc_pedit.h>

#define PEDIT_TAB_MASK  15
static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1];
static u32 pedit_idx_gen;
static DEFINE_RWLOCK(pedit_lock);

static struct tcf_hashinfo pedit_hash_info = {
        .htab   =       tcf_pedit_ht,
        .hmask  =       PEDIT_TAB_MASK,
        .lock   =       &pedit_lock,
};

static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
        [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tcf_pedit) },
};

static int tcf_pedit_init(struct nlattr *nla, struct nlattr *est,
                          struct tc_action *a, int ovr, int bind)
{
        struct nlattr *tb[TCA_PEDIT_MAX + 1];
        struct tc_pedit *parm;
        int ret = 0, err;
        struct tcf_pedit *p;
        struct tcf_common *pc;
        struct tc_pedit_key *keys = NULL;
        int ksize;

        if (nla == NULL)
                return -EINVAL;

        err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy);
        if (err < 0)
                return err;

        if (tb[TCA_PEDIT_PARMS] == NULL)
                return -EINVAL;
        parm = nla_data(tb[TCA_PEDIT_PARMS]);
        ksize = parm->nkeys * sizeof(struct tc_pedit_key);
        if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize)
                return -EINVAL;

        pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info);
        if (!pc) {
                if (!parm->nkeys)
                        return -EINVAL;
                pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
                                     &pedit_idx_gen, &pedit_hash_info);
                if (unlikely(!pc))
                        return -ENOMEM;
                p = to_pedit(pc);
                keys = kmalloc(ksize, GFP_KERNEL);
                if (keys == NULL) {
                        kfree(pc);
                        return -ENOMEM;
                }
                ret = ACT_P_CREATED;
        } else {
                p = to_pedit(pc);
                if (!ovr) {
                        tcf_hash_release(pc, bind, &pedit_hash_info);
                        return -EEXIST;
                }
                if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
                        keys = kmalloc(ksize, GFP_KERNEL);
                        if (keys == NULL)
                                return -ENOMEM;
                }
        }

        spin_lock_bh(&p->tcf_lock);
        p->tcfp_flags = parm->flags;
        p->tcf_action = parm->action;
        if (keys) {
                kfree(p->tcfp_keys);
                p->tcfp_keys = keys;
                p->tcfp_nkeys = parm->nkeys;
        }
        memcpy(p->tcfp_keys, parm->keys, ksize);
        spin_unlock_bh(&p->tcf_lock);
        if (ret == ACT_P_CREATED)
                tcf_hash_insert(pc, &pedit_hash_info);
        return ret;
}

static int tcf_pedit_cleanup(struct tc_action *a, int bind)
{
        struct tcf_pedit *p = a->priv;

        if (p) {
                struct tc_pedit_key *keys = p->tcfp_keys;
                if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) {
                        kfree(keys);
                        return 1;
                }
        }
        return 0;
}

static int tcf_pedit(struct sk_buff *skb, struct tc_action *a,
                     struct tcf_result *res)
{
        struct tcf_pedit *p = a->priv;
        int i, munged = 0;
        u8 *pptr;

        if (!(skb->tc_verd & TC_OK2MUNGE)) {
                /* should we set skb->cloned? */
                if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
                        return p->tcf_action;
                }
        }

        pptr = skb_network_header(skb);

        spin_lock(&p->tcf_lock);

        p->tcf_tm.lastuse = jiffies;

        if (p->tcfp_nkeys > 0) {
                struct tc_pedit_key *tkey = p->tcfp_keys;

                for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
                        u32 *ptr;
                        int offset = tkey->off;

                        if (tkey->offmask) {
                                if (skb->len > tkey->at) {
                                         char *j = pptr + tkey->at;
                                         offset += ((*j & tkey->offmask) >>
                                                   tkey->shift);
                                } else {
                                        goto bad;
                                }
                        }

                        if (offset % 4) {
                                printk("offset must be on 32 bit boundaries\n");
                                goto bad;
                        }
                        if (offset > 0 && offset > skb->len) {
                                printk("offset %d cant exceed pkt length %d\n",
                                       offset, skb->len);
                                goto bad;
                        }

                        ptr = (u32 *)(pptr+offset);
                        /* just do it, baby */
                        *ptr = ((*ptr & tkey->mask) ^ tkey->val);
                        munged++;
                }

                if (munged)
                        skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
                goto done;
        } else {
                printk("pedit BUG: index %d\n", p->tcf_index);
        }

bad:
        p->tcf_qstats.overlimits++;
done:
        p->tcf_bstats.bytes += qdisc_pkt_len(skb);
        p->tcf_bstats.packets++;
        spin_unlock(&p->tcf_lock);
        return p->tcf_action;
}

static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
                          int bind, int ref)
{
        unsigned char *b = skb_tail_pointer(skb);
        struct tcf_pedit *p = a->priv;
        struct tc_pedit *opt;
        struct tcf_t t;
        int s;

        s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);

        /* netlink spinlocks held above us - must use ATOMIC */
        opt = kzalloc(s, GFP_ATOMIC);
        if (unlikely(!opt))
                return -ENOBUFS;

        memcpy(opt->keys, p->tcfp_keys,
               p->tcfp_nkeys * sizeof(struct tc_pedit_key));
        opt->index = p->tcf_index;
        opt->nkeys = p->tcfp_nkeys;
        opt->flags = p->tcfp_flags;
        opt->action = p->tcf_action;
        opt->refcnt = p->tcf_refcnt - ref;
        opt->bindcnt = p->tcf_bindcnt - bind;

        NLA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
        t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
        t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
        t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
        NLA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);
        kfree(opt);
        return skb->len;

nla_put_failure:
        nlmsg_trim(skb, b);
        kfree(opt);
        return -1;
}

static struct tc_action_ops act_pedit_ops = {
        .kind           =       "pedit",
        .hinfo          =       &pedit_hash_info,
        .type           =       TCA_ACT_PEDIT,
        .capab          =       TCA_CAP_NONE,
        .owner          =       THIS_MODULE,
        .act            =       tcf_pedit,
        .dump           =       tcf_pedit_dump,
        .cleanup        =       tcf_pedit_cleanup,
        .lookup         =       tcf_hash_search,
        .init           =       tcf_pedit_init,
        .walk           =       tcf_generic_walker
};

MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
MODULE_DESCRIPTION("Generic Packet Editor actions");
MODULE_LICENSE("GPL");

static int __init pedit_init_module(void)
{
        return tcf_register_action(&act_pedit_ops);
}

static void __exit pedit_cleanup_module(void)
{
        tcf_unregister_action(&act_pedit_ops);
}

module_init(pedit_init_module);
module_exit(pedit_cleanup_module);


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