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root/net/sched/sch_dsmark.c

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DEFINITIONS

This source file includes following definitions.
  1. dsmark_valid_index
  2. dsmark_graft
  3. dsmark_leaf
  4. dsmark_get
  5. dsmark_bind_filter
  6. dsmark_put
  7. dsmark_change
  8. dsmark_delete
  9. dsmark_walk
  10. dsmark_find_tcf
  11. dsmark_enqueue
  12. dsmark_dequeue
  13. dsmark_requeue
  14. dsmark_drop
  15. dsmark_init
  16. dsmark_reset
  17. dsmark_destroy
  18. dsmark_dump_class
  19. dsmark_dump
  20. dsmark_module_init
  21. dsmark_module_exit

/* net/sched/sch_dsmark.c - Differentiated Services field marker */

/* Written 1998-2000 by Werner Almesberger, EPFL ICA */


#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/bitops.h>
#include <net/pkt_sched.h>
#include <net/dsfield.h>
#include <net/inet_ecn.h>
#include <asm/byteorder.h>

/*
 * classid      class           marking
 * -------      -----           -------
 *   n/a          0             n/a
 *   x:0          1             use entry [0]
 *   ...         ...            ...
 *   x:y y>0     y+1            use entry [y]
 *   ...         ...            ...
 * x:indices-1  indices         use entry [indices-1]
 *   ...         ...            ...
 *   x:y         y+1            use entry [y & (indices-1)]
 *   ...         ...            ...
 * 0xffff       0x10000         use entry [indices-1]
 */


#define NO_DEFAULT_INDEX        (1 << 16)

struct dsmark_qdisc_data {
        struct Qdisc            *q;
        struct tcf_proto        *filter_list;
        u8                      *mask;  /* "owns" the array */
        u8                      *value;
        u16                     indices;
        u32                     default_index;  /* index range is 0...0xffff */
        int                     set_tc_index;
};

static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
{
        return (index <= p->indices && index > 0);
}

/* ------------------------- Class/flow operations ------------------------- */

static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
                        struct Qdisc *new, struct Qdisc **old)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);

        pr_debug("dsmark_graft(sch %p,[qdisc %p],new %p,old %p)\n",
                sch, p, new, old);

        if (new == NULL) {
                new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
                                        &pfifo_qdisc_ops,
                                        sch->handle);
                if (new == NULL)
                        new = &noop_qdisc;
        }

        sch_tree_lock(sch);
        *old = xchg(&p->q, new);
        qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
        qdisc_reset(*old);
        sch_tree_unlock(sch);

        return 0;
}

static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        return p->q;
}

static unsigned long dsmark_get(struct Qdisc *sch, u32 classid)
{
        pr_debug("dsmark_get(sch %p,[qdisc %p],classid %x)\n",
                sch, qdisc_priv(sch), classid);

        return TC_H_MIN(classid) + 1;
}

static unsigned long dsmark_bind_filter(struct Qdisc *sch,
                                        unsigned long parent, u32 classid)
{
        return dsmark_get(sch, classid);
}

static void dsmark_put(struct Qdisc *sch, unsigned long cl)
{
}

static const struct nla_policy dsmark_policy[TCA_DSMARK_MAX + 1] = {
        [TCA_DSMARK_INDICES]            = { .type = NLA_U16 },
        [TCA_DSMARK_DEFAULT_INDEX]      = { .type = NLA_U16 },
        [TCA_DSMARK_SET_TC_INDEX]       = { .type = NLA_FLAG },
        [TCA_DSMARK_MASK]               = { .type = NLA_U8 },
        [TCA_DSMARK_VALUE]              = { .type = NLA_U8 },
};

static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
                         struct nlattr **tca, unsigned long *arg)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        struct nlattr *opt = tca[TCA_OPTIONS];
        struct nlattr *tb[TCA_DSMARK_MAX + 1];
        int err = -EINVAL;
        u8 mask = 0;

        pr_debug("dsmark_change(sch %p,[qdisc %p],classid %x,parent %x),"
                "arg 0x%lx\n", sch, p, classid, parent, *arg);

        if (!dsmark_valid_index(p, *arg)) {
                err = -ENOENT;
                goto errout;
        }

        if (!opt)
                goto errout;

        err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
        if (err < 0)
                goto errout;

        if (tb[TCA_DSMARK_MASK])
                mask = nla_get_u8(tb[TCA_DSMARK_MASK]);

        if (tb[TCA_DSMARK_VALUE])
                p->value[*arg-1] = nla_get_u8(tb[TCA_DSMARK_VALUE]);

        if (tb[TCA_DSMARK_MASK])
                p->mask[*arg-1] = mask;

        err = 0;

errout:
        return err;
}

static int dsmark_delete(struct Qdisc *sch, unsigned long arg)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);

        if (!dsmark_valid_index(p, arg))
                return -EINVAL;

        p->mask[arg-1] = 0xff;
        p->value[arg-1] = 0;

        return 0;
}

static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        int i;

        pr_debug("dsmark_walk(sch %p,[qdisc %p],walker %p)\n", sch, p, walker);

        if (walker->stop)
                return;

        for (i = 0; i < p->indices; i++) {
                if (p->mask[i] == 0xff && !p->value[i])
                        goto ignore;
                if (walker->count >= walker->skip) {
                        if (walker->fn(sch, i+1, walker) < 0) {
                                walker->stop = 1;
                                break;
                        }
                }
ignore:
                walker->count++;
        }
}

static inline struct tcf_proto **dsmark_find_tcf(struct Qdisc *sch,
                                                 unsigned long cl)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        return &p->filter_list;
}

/* --------------------------- Qdisc operations ---------------------------- */

static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        int err;

        pr_debug("dsmark_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);

        if (p->set_tc_index) {
                switch (skb->protocol) {
                case htons(ETH_P_IP):
                        if (skb_cow_head(skb, sizeof(struct iphdr)))
                                goto drop;

                        skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
                                & ~INET_ECN_MASK;
                        break;

                case htons(ETH_P_IPV6):
                        if (skb_cow_head(skb, sizeof(struct ipv6hdr)))
                                goto drop;

                        skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
                                & ~INET_ECN_MASK;
                        break;
                default:
                        skb->tc_index = 0;
                        break;
                }
        }

        if (TC_H_MAJ(skb->priority) == sch->handle)
                skb->tc_index = TC_H_MIN(skb->priority);
        else {
                struct tcf_result res;
                int result = tc_classify(skb, p->filter_list, &res);

                pr_debug("result %d class 0x%04x\n", result, res.classid);

                switch (result) {
#ifdef CONFIG_NET_CLS_ACT
                case TC_ACT_QUEUED:
                case TC_ACT_STOLEN:
                        kfree_skb(skb);
                        return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;

                case TC_ACT_SHOT:
                        goto drop;
#endif
                case TC_ACT_OK:
                        skb->tc_index = TC_H_MIN(res.classid);
                        break;

                default:
                        if (p->default_index != NO_DEFAULT_INDEX)
                                skb->tc_index = p->default_index;
                        break;
                }
        }

        err = qdisc_enqueue(skb, p->q);
        if (err != NET_XMIT_SUCCESS) {
                if (net_xmit_drop_count(err))
                        sch->qstats.drops++;
                return err;
        }

        sch->bstats.bytes += qdisc_pkt_len(skb);
        sch->bstats.packets++;
        sch->q.qlen++;

        return NET_XMIT_SUCCESS;

drop:
        kfree_skb(skb);
        sch->qstats.drops++;
        return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
}

static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        struct sk_buff *skb;
        u32 index;

        pr_debug("dsmark_dequeue(sch %p,[qdisc %p])\n", sch, p);

        skb = p->q->ops->dequeue(p->q);
        if (skb == NULL)
                return NULL;

        sch->q.qlen--;

        index = skb->tc_index & (p->indices - 1);
        pr_debug("index %d->%d\n", skb->tc_index, index);

        switch (skb->protocol) {
        case htons(ETH_P_IP):
                ipv4_change_dsfield(ip_hdr(skb), p->mask[index],
                                    p->value[index]);
                        break;
        case htons(ETH_P_IPV6):
                ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],
                                    p->value[index]);
                        break;
        default:
                /*
                 * Only complain if a change was actually attempted.
                 * This way, we can send non-IP traffic through dsmark
                 * and don't need yet another qdisc as a bypass.
                 */
                if (p->mask[index] != 0xff || p->value[index])
                        printk(KERN_WARNING
                               "dsmark_dequeue: unsupported protocol %d\n",
                               ntohs(skb->protocol));
                break;
        }

        return skb;
}

static int dsmark_requeue(struct sk_buff *skb, struct Qdisc *sch)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        int err;

        pr_debug("dsmark_requeue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);

        err = p->q->ops->requeue(skb, p->q);
        if (err != NET_XMIT_SUCCESS) {
                if (net_xmit_drop_count(err))
                        sch->qstats.drops++;
                return err;
        }

        sch->q.qlen++;
        sch->qstats.requeues++;

        return NET_XMIT_SUCCESS;
}

static unsigned int dsmark_drop(struct Qdisc *sch)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        unsigned int len;

        pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);

        if (p->q->ops->drop == NULL)
                return 0;

        len = p->q->ops->drop(p->q);
        if (len)
                sch->q.qlen--;

        return len;
}

static int dsmark_init(struct Qdisc *sch, struct nlattr *opt)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        struct nlattr *tb[TCA_DSMARK_MAX + 1];
        int err = -EINVAL;
        u32 default_index = NO_DEFAULT_INDEX;
        u16 indices;
        u8 *mask;

        pr_debug("dsmark_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);

        if (!opt)
                goto errout;

        err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
        if (err < 0)
                goto errout;

        err = -EINVAL;
        indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);

        if (hweight32(indices) != 1)
                goto errout;

        if (tb[TCA_DSMARK_DEFAULT_INDEX])
                default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);

        mask = kmalloc(indices * 2, GFP_KERNEL);
        if (mask == NULL) {
                err = -ENOMEM;
                goto errout;
        }

        p->mask = mask;
        memset(p->mask, 0xff, indices);

        p->value = p->mask + indices;
        memset(p->value, 0, indices);

        p->indices = indices;
        p->default_index = default_index;
        p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);

        p->q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
                                 &pfifo_qdisc_ops, sch->handle);
        if (p->q == NULL)
                p->q = &noop_qdisc;

        pr_debug("dsmark_init: qdisc %p\n", p->q);

        err = 0;
errout:
        return err;
}

static void dsmark_reset(struct Qdisc *sch)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);

        pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
        qdisc_reset(p->q);
        sch->q.qlen = 0;
}

static void dsmark_destroy(struct Qdisc *sch)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);

        pr_debug("dsmark_destroy(sch %p,[qdisc %p])\n", sch, p);

        tcf_destroy_chain(&p->filter_list);
        qdisc_destroy(p->q);
        kfree(p->mask);
}

static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
                             struct sk_buff *skb, struct tcmsg *tcm)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        struct nlattr *opts = NULL;

        pr_debug("dsmark_dump_class(sch %p,[qdisc %p],class %ld\n", sch, p, cl);

        if (!dsmark_valid_index(p, cl))
                return -EINVAL;

        tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl-1);
        tcm->tcm_info = p->q->handle;

        opts = nla_nest_start(skb, TCA_OPTIONS);
        if (opts == NULL)
                goto nla_put_failure;
        NLA_PUT_U8(skb, TCA_DSMARK_MASK, p->mask[cl-1]);
        NLA_PUT_U8(skb, TCA_DSMARK_VALUE, p->value[cl-1]);

        return nla_nest_end(skb, opts);

nla_put_failure:
        nla_nest_cancel(skb, opts);
        return -EMSGSIZE;
}

static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
{
        struct dsmark_qdisc_data *p = qdisc_priv(sch);
        struct nlattr *opts = NULL;

        opts = nla_nest_start(skb, TCA_OPTIONS);
        if (opts == NULL)
                goto nla_put_failure;
        NLA_PUT_U16(skb, TCA_DSMARK_INDICES, p->indices);

        if (p->default_index != NO_DEFAULT_INDEX)
                NLA_PUT_U16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index);

        if (p->set_tc_index)
                NLA_PUT_FLAG(skb, TCA_DSMARK_SET_TC_INDEX);

        return nla_nest_end(skb, opts);

nla_put_failure:
        nla_nest_cancel(skb, opts);
        return -EMSGSIZE;
}

static const struct Qdisc_class_ops dsmark_class_ops = {
        .graft          =       dsmark_graft,
        .leaf           =       dsmark_leaf,
        .get            =       dsmark_get,
        .put            =       dsmark_put,
        .change         =       dsmark_change,
        .delete         =       dsmark_delete,
        .walk           =       dsmark_walk,
        .tcf_chain      =       dsmark_find_tcf,
        .bind_tcf       =       dsmark_bind_filter,
        .unbind_tcf     =       dsmark_put,
        .dump           =       dsmark_dump_class,
};

static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
        .next           =       NULL,
        .cl_ops         =       &dsmark_class_ops,
        .id             =       "dsmark",
        .priv_size      =       sizeof(struct dsmark_qdisc_data),
        .enqueue        =       dsmark_enqueue,
        .dequeue        =       dsmark_dequeue,
        .requeue        =       dsmark_requeue,
        .drop           =       dsmark_drop,
        .init           =       dsmark_init,
        .reset          =       dsmark_reset,
        .destroy        =       dsmark_destroy,
        .change         =       NULL,
        .dump           =       dsmark_dump,
        .owner          =       THIS_MODULE,
};

static int __init dsmark_module_init(void)
{
        return register_qdisc(&dsmark_qdisc_ops);
}

static void __exit dsmark_module_exit(void)
{
        unregister_qdisc(&dsmark_qdisc_ops);
}

module_init(dsmark_module_init)
module_exit(dsmark_module_exit)

MODULE_LICENSE("GPL");

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