sch_dsmark.c 11.4 KB
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/* 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>
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#include <linux/bitops.h>
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#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;
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	u8			*mask;	/* "owns" the array */
	u8			*value;
	u16			indices;
	u32			default_index;	/* index range is 0...0xffff */
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	int			set_tc_index;
};

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

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static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
			struct Qdisc *new, struct Qdisc **old)
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{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	pr_debug("dsmark_graft(sch %p,[qdisc %p],new %p,old %p)\n",
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		sch, p, new, old);
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	if (new == NULL) {
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		new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
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					&pfifo_qdisc_ops,
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					sch->handle);
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		if (new == NULL)
			new = &noop_qdisc;
	}

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

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	return 0;
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}

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

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static unsigned long dsmark_get(struct Qdisc *sch, u32 classid)
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{
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	pr_debug("dsmark_get(sch %p,[qdisc %p],classid %x)\n",
		sch, qdisc_priv(sch), classid);
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	return TC_H_MIN(classid) + 1;
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}

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

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

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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 },
};

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

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

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	if (!opt)
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		goto errout;
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	err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
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	if (err < 0)
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		goto errout;
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	if (tb[TCA_DSMARK_MASK])
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		mask = nla_get_u8(tb[TCA_DSMARK_MASK]);
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	if (tb[TCA_DSMARK_VALUE])
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		p->value[*arg-1] = nla_get_u8(tb[TCA_DSMARK_VALUE]);
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	if (tb[TCA_DSMARK_MASK])
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		p->mask[*arg-1] = mask;

	err = 0;

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errout:
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	return err;
}
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static int dsmark_delete(struct Qdisc *sch, unsigned long arg)
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{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	if (!dsmark_valid_index(p, arg))
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		return -EINVAL;
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	p->mask[arg-1] = 0xff;
	p->value[arg-1] = 0;
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	return 0;
}

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

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

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

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

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

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	pr_debug("dsmark_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
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	if (p->set_tc_index) {
		switch (skb->protocol) {
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		case htons(ETH_P_IP):
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			if (skb_cow_head(skb, sizeof(struct iphdr)))
				goto drop;
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			skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
				& ~INET_ECN_MASK;
			break;
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		case htons(ETH_P_IPV6):
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			if (skb_cow_head(skb, sizeof(struct ipv6hdr)))
				goto drop;
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			skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
				& ~INET_ECN_MASK;
			break;
		default:
			skb->tc_index = 0;
			break;
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		}
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	}
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	if (TC_H_MAJ(skb->priority) == sch->handle)
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		skb->tc_index = TC_H_MIN(skb->priority);
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	else {
		struct tcf_result res;
		int result = tc_classify(skb, p->filter_list, &res);

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		pr_debug("result %d class 0x%04x\n", result, res.classid);
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		switch (result) {
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#ifdef CONFIG_NET_CLS_ACT
		case TC_ACT_QUEUED:
		case TC_ACT_STOLEN:
			kfree_skb(skb);
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			return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
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		case TC_ACT_SHOT:
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			goto drop;
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#endif
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		case TC_ACT_OK:
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			skb->tc_index = TC_H_MIN(res.classid);
			break;
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		default:
			if (p->default_index != NO_DEFAULT_INDEX)
				skb->tc_index = p->default_index;
			break;
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		}
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	}

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

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	return NET_XMIT_SUCCESS;
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drop:
	kfree_skb(skb);
	sch->qstats.drops++;
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	return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
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}
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static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	struct sk_buff *skb;
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	u32 index;

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	pr_debug("dsmark_dequeue(sch %p,[qdisc %p])\n", sch, p);
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	skb = p->q->ops->dequeue(p->q);
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	if (skb == NULL)
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		return NULL;
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	sch->q.qlen--;
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	index = skb->tc_index & (p->indices - 1);
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	pr_debug("index %d->%d\n", skb->tc_index, index);
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	switch (skb->protocol) {
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	case htons(ETH_P_IP):
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		ipv4_change_dsfield(ip_hdr(skb), p->mask[index],
				    p->value[index]);
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			break;
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	case htons(ETH_P_IPV6):
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		ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],
				    p->value[index]);
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			break;
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	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;
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	}
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	return skb;
}

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static int dsmark_requeue(struct sk_buff *skb, struct Qdisc *sch)
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{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	int err;
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	pr_debug("dsmark_requeue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
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	err = p->q->ops->requeue(skb, p->q);
	if (err != NET_XMIT_SUCCESS) {
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		if (net_xmit_drop_count(err))
			sch->qstats.drops++;
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		return err;
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	}

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

	return NET_XMIT_SUCCESS;
}
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static unsigned int dsmark_drop(struct Qdisc *sch)
{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	unsigned int len;
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	pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
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	if (p->q->ops->drop == NULL)
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		return 0;
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	len = p->q->ops->drop(p->q);
	if (len)
		sch->q.qlen--;

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	return len;
}

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

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

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

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	err = -EINVAL;
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	indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
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	if (hweight32(indices) != 1)
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		goto errout;

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	if (tb[TCA_DSMARK_DEFAULT_INDEX])
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		default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
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	mask = kmalloc(indices * 2, GFP_KERNEL);
	if (mask == NULL) {
		err = -ENOMEM;
		goto errout;
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	}
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	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;
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	p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
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	p->q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
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				 &pfifo_qdisc_ops, sch->handle);
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	if (p->q == NULL)
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		p->q = &noop_qdisc;
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	pr_debug("dsmark_init: qdisc %p\n", p->q);
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	err = 0;
errout:
	return err;
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}

static void dsmark_reset(struct Qdisc *sch)
{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
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	qdisc_reset(p->q);
	sch->q.qlen = 0;
}

static void dsmark_destroy(struct Qdisc *sch)
{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	pr_debug("dsmark_destroy(sch %p,[qdisc %p])\n", sch, p);
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	tcf_destroy_chain(&p->filter_list);
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	qdisc_destroy(p->q);
	kfree(p->mask);
}

static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
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			     struct sk_buff *skb, struct tcmsg *tcm)
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{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	struct nlattr *opts = NULL;
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	pr_debug("dsmark_dump_class(sch %p,[qdisc %p],class %ld\n", sch, p, cl);
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	if (!dsmark_valid_index(p, cl))
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		return -EINVAL;
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	tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl-1);
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	tcm->tcm_info = p->q->handle;
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	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]);
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	return nla_nest_end(skb, opts);
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nla_put_failure:
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	nla_nest_cancel(skb, opts);
	return -EMSGSIZE;
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}

static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
{
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	struct dsmark_qdisc_data *p = qdisc_priv(sch);
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	struct nlattr *opts = NULL;
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	opts = nla_nest_start(skb, TCA_OPTIONS);
	if (opts == NULL)
		goto nla_put_failure;
	NLA_PUT_U16(skb, TCA_DSMARK_INDICES, p->indices);
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	if (p->default_index != NO_DEFAULT_INDEX)
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		NLA_PUT_U16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index);
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	if (p->set_tc_index)
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		NLA_PUT_FLAG(skb, TCA_DSMARK_SET_TC_INDEX);
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	return nla_nest_end(skb, opts);
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nla_put_failure:
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	nla_nest_cancel(skb, opts);
	return -EMSGSIZE;
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}

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static const struct Qdisc_class_ops dsmark_class_ops = {
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	.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,
};

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static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
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	.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);
}
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static void __exit dsmark_module_exit(void)
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{
	unregister_qdisc(&dsmark_qdisc_ops);
}
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module_init(dsmark_module_init)
module_exit(dsmark_module_exit)
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MODULE_LICENSE("GPL");