act_skbedit.c

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/*
 * Copyright (c) 2008, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Author: Alexander Duyck <[email protected]>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>

#include <linux/tc_act/tc_skbedit.h>
#include <net/tc_act/tc_skbedit.h>

#define SKBEDIT_TAB_MASK     15
static struct tcf_common *tcf_skbedit_ht[SKBEDIT_TAB_MASK + 1];
static u32 skbedit_idx_gen;
static DEFINE_RWLOCK(skbedit_lock);

static struct tcf_hashinfo skbedit_hash_info = {
    .htab   =   tcf_skbedit_ht,
    .hmask  =   SKBEDIT_TAB_MASK,
    .lock   =   &skbedit_lock,
};

static int tcf_skbedit(struct sk_buff *skb, const struct tc_action *a,
               struct tcf_result *res)
{
    struct tcf_skbedit *d = a->priv;

    spin_lock(&d->tcf_lock);
    d->tcf_tm.lastuse = jiffies;
    bstats_update(&d->tcf_bstats, skb);

    if (d->flags & SKBEDIT_F_PRIORITY)
        skb->priority = d->priority;
    if (d->flags & SKBEDIT_F_QUEUE_MAPPING &&
        skb->dev->real_num_tx_queues > d->queue_mapping)
        skb_set_queue_mapping(skb, d->queue_mapping);
    if (d->flags & SKBEDIT_F_MARK)
        skb->mark = d->mark;

    spin_unlock(&d->tcf_lock);
    return d->tcf_action;
}

static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = {
    [TCA_SKBEDIT_PARMS]     = { .len = sizeof(struct tc_skbedit) },
    [TCA_SKBEDIT_PRIORITY]      = { .len = sizeof(u32) },
    [TCA_SKBEDIT_QUEUE_MAPPING] = { .len = sizeof(u16) },
    [TCA_SKBEDIT_MARK]      = { .len = sizeof(u32) },
};

static int tcf_skbedit_init(struct nlattr *nla, struct nlattr *est,
             struct tc_action *a, int ovr, int bind)
{
    struct nlattr *tb[TCA_SKBEDIT_MAX + 1];
    struct tc_skbedit *parm;
    struct tcf_skbedit *d;
    struct tcf_common *pc;
    u32 flags = 0, *priority = NULL, *mark = NULL;
    u16 *queue_mapping = NULL;
    int ret = 0, err;

    if (nla == NULL)
        return -EINVAL;

    err = nla_parse_nested(tb, TCA_SKBEDIT_MAX, nla, skbedit_policy);
    if (err < 0)
        return err;

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

    if (tb[TCA_SKBEDIT_PRIORITY] != NULL) {
        flags |= SKBEDIT_F_PRIORITY;
        priority = nla_data(tb[TCA_SKBEDIT_PRIORITY]);
    }

    if (tb[TCA_SKBEDIT_QUEUE_MAPPING] != NULL) {
        flags |= SKBEDIT_F_QUEUE_MAPPING;
        queue_mapping = nla_data(tb[TCA_SKBEDIT_QUEUE_MAPPING]);
    }

    if (tb[TCA_SKBEDIT_MARK] != NULL) {
        flags |= SKBEDIT_F_MARK;
        mark = nla_data(tb[TCA_SKBEDIT_MARK]);
    }

    if (!flags)
        return -EINVAL;

    parm = nla_data(tb[TCA_SKBEDIT_PARMS]);

    pc = tcf_hash_check(parm->index, a, bind, &skbedit_hash_info);
    if (!pc) {
        pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
                     &skbedit_idx_gen, &skbedit_hash_info);
        if (IS_ERR(pc))
            return PTR_ERR(pc);

        d = to_skbedit(pc);
        ret = ACT_P_CREATED;
    } else {
        d = to_skbedit(pc);
        if (!ovr) {
            tcf_hash_release(pc, bind, &skbedit_hash_info);
            return -EEXIST;
        }
    }

    spin_lock_bh(&d->tcf_lock);

    d->flags = flags;
    if (flags & SKBEDIT_F_PRIORITY)
        d->priority = *priority;
    if (flags & SKBEDIT_F_QUEUE_MAPPING)
        d->queue_mapping = *queue_mapping;
    if (flags & SKBEDIT_F_MARK)
        d->mark = *mark;

    d->tcf_action = parm->action;

    spin_unlock_bh(&d->tcf_lock);

    if (ret == ACT_P_CREATED)
        tcf_hash_insert(pc, &skbedit_hash_info);
    return ret;
}

static int tcf_skbedit_cleanup(struct tc_action *a, int bind)
{
    struct tcf_skbedit *d = a->priv;

    if (d)
        return tcf_hash_release(&d->common, bind, &skbedit_hash_info);
    return 0;
}

static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
                int bind, int ref)
{
    unsigned char *b = skb_tail_pointer(skb);
    struct tcf_skbedit *d = a->priv;
    struct tc_skbedit opt = {
        .index   = d->tcf_index,
        .refcnt  = d->tcf_refcnt - ref,
        .bindcnt = d->tcf_bindcnt - bind,
        .action  = d->tcf_action,
    };
    struct tcf_t t;

    if (nla_put(skb, TCA_SKBEDIT_PARMS, sizeof(opt), &opt))
        goto nla_put_failure;
    if ((d->flags & SKBEDIT_F_PRIORITY) &&
        nla_put(skb, TCA_SKBEDIT_PRIORITY, sizeof(d->priority),
            &d->priority))
        goto nla_put_failure;
    if ((d->flags & SKBEDIT_F_QUEUE_MAPPING) &&
        nla_put(skb, TCA_SKBEDIT_QUEUE_MAPPING,
            sizeof(d->queue_mapping), &d->queue_mapping))
        goto nla_put_failure;
    if ((d->flags & SKBEDIT_F_MARK) &&
        nla_put(skb, TCA_SKBEDIT_MARK, sizeof(d->mark),
            &d->mark))
        goto nla_put_failure;
    t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
    t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
    t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
    if (nla_put(skb, TCA_SKBEDIT_TM, sizeof(t), &t))
        goto nla_put_failure;
    return skb->len;

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

static struct tc_action_ops act_skbedit_ops = {
    .kind       =   "skbedit",
    .hinfo      =   &skbedit_hash_info,
    .type       =   TCA_ACT_SKBEDIT,
    .capab      =   TCA_CAP_NONE,
    .owner      =   THIS_MODULE,
    .act        =   tcf_skbedit,
    .dump       =   tcf_skbedit_dump,
    .cleanup    =   tcf_skbedit_cleanup,
    .init       =   tcf_skbedit_init,
    .walk       =   tcf_generic_walker,
};

MODULE_AUTHOR("Alexander Duyck, <[email protected]>");
MODULE_DESCRIPTION("SKB Editing");
MODULE_LICENSE("GPL");

static int __init skbedit_init_module(void)
{
    return tcf_register_action(&act_skbedit_ops);
}

static void __exit skbedit_cleanup_module(void)
{
    tcf_unregister_action(&act_skbedit_ops);
}

module_init(skbedit_init_module);
module_exit(skbedit_cleanup_module);