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/*

 * 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 int tcf_pedit_init(struct rtattr *rta, struct rtattr *est,

                          struct tc_action *a, int ovr, int bind)

{

        struct rtattr *tb[TCA_PEDIT_MAX];

        struct tc_pedit *parm;

        int ret = 0;

        struct tcf_pedit *p;

        struct tcf_common *pc;

        struct tc_pedit_key *keys = NULL;

        int ksize;

        if (rta == NULL || rtattr_parse_nested(tb, TCA_PEDIT_MAX, rta) < 0)

                return -EINVAL;

        if (tb[TCA_PEDIT_PARMS - 1] == NULL ||

            RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < sizeof(*parm))

                return -EINVAL;

        parm = RTA_DATA(tb[TCA_PEDIT_PARMS-1]);

        ksize = parm->nkeys * sizeof(struct tc_pedit_key);

        if (RTA_PAYLOAD(tb[TCA_PEDIT_PARMS-1]) < 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 += skb->len;

        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;

        RTA_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);

        RTA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);

        kfree(opt);

        return skb->len;

rtattr_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);