linux-imx

/*

 * 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 <asm/unaligned.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 = get_unaligned_be16(ptr);

​

        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 = get_unaligned_be32(ptr);

​

        if (cmp_needs_transformation(cmp))

            val = be32_to_cpu(val);

        break;

​

    default:

        return 0;

    }

​

    if (cmp->mask)

        val &= cmp->mask;

​