Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * net/sched/em_cmp.c   Simple packet data comparison ematch

 *

 *              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:     Thomas Graf <tgraf@suug.ch>

 */

#include <linux/module.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/skbuff.h>

#include <linux/tc_ematch/tc_em_cmp.h>

#include <net/pkt_cls.h>

static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp)

{

        return unlikely(cmp->flags & TCF_EM_CMP_TRANS);

}

static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em,

                        struct tcf_pkt_info *info)

{

        struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data;

        unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off;

        u32 val = 0;

        if (!tcf_valid_offset(skb, ptr, cmp->align))

                return 0;

        switch (cmp->align) {

                case TCF_EM_ALIGN_U8:

                        val = *ptr;

                        break;

                case TCF_EM_ALIGN_U16:

                        val = *ptr << 8;

                        val |= *(ptr+1);

                        if (cmp_needs_transformation(cmp))

                                val = be16_to_cpu(val);

                        break;

                case TCF_EM_ALIGN_U32:

                        /* Worth checking boundries? The branching seems

                         * to get worse. Visit again. */

                        val = *ptr << 24;

                        val |= *(ptr+1) << 16;

                        val |= *(ptr+2) << 8;

                        val |= *(ptr+3);

                        if (cmp_needs_transformation(cmp))

                                val = be32_to_cpu(val);

                        break;

                default:

                        return 0;

        }

        if (cmp->mask)

                val &= cmp->mask;

        switch (cmp->opnd) {

                case TCF_EM_OPND_EQ:

                        return val == cmp->val;

                case TCF_EM_OPND_LT:

                        return val < cmp->val;

                case TCF_EM_OPND_GT:

                        return val > cmp->val;

        }

        return 0;

}

static struct tcf_ematch_ops em_cmp_ops = {

        .kind     = TCF_EM_CMP,

        .datalen  = sizeof(struct tcf_em_cmp),

        .match    = em_cmp_match,

        .owner    = THIS_MODULE,

        .link     = LIST_HEAD_INIT(em_cmp_ops.link)

};

static int __init init_em_cmp(void)

{

        return tcf_em_register(&em_cmp_ops);

}

static void __exit exit_em_cmp(void)

{

        tcf_em_unregister(&em_cmp_ops);

}

MODULE_LICENSE("GPL");

module_init(init_em_cmp);

module_exit(exit_em_cmp);

MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);