net/sched/sch_dsmark.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /* 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/slab.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/pkt_cls.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 mask_value {
 	u8			mask;
 	u8			value;
 };

 struct dsmark_qdisc_data {
 	struct Qdisc		*q;
 	struct tcf_proto __rcu	*filter_list;
 	struct tcf_block	*block;
 	struct mask_value	*mv;
 	u16			indices;
 	u8			set_tc_index;
 	u32			default_index;	/* index range is 0...0xffff */
 #define DSMARK_EMBEDDED_SZ	16
 	struct mask_value	embedded[DSMARK_EMBEDDED_SZ];
 };

 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 netlink_ext_ack *extack)
 {
 	struct dsmark_qdisc_data *p = qdisc_priv(sch);

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

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

 	*old = qdisc_replace(sch, new, &p->q);
 	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_find(struct Qdisc *sch, u32 classid)
 {
 	return TC_H_MIN(classid) + 1;
 }

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

 	return dsmark_find(sch, classid);
 }

 static void dsmark_unbind_filter(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 netlink_ext_ack *extack)
 {
 	struct dsmark_qdisc_data *p = qdisc_priv(sch);
 	struct nlattr *opt = tca[TCA_OPTIONS];
 	struct nlattr *tb[TCA_DSMARK_MAX + 1];
 	int err = -EINVAL;

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

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

 	if (!opt)
 		goto errout;

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

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

 	if (tb[TCA_DSMARK_MASK])
 		p->mv[*arg - 1].mask = nla_get_u8(tb[TCA_DSMARK_MASK]);

 	err = 0;

 errout:
 	return err;
 }

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

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

 	p->mv[arg - 1].mask = 0xff;
 	p->mv[arg - 1].value = 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("%s(sch %p,[qdisc %p],walker %p)\n",
 		 __func__, sch, p, walker);

 	if (walker->stop)
 		return;

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

 static struct tcf_block *dsmark_tcf_block(struct Qdisc *sch, unsigned long cl,
 					  struct netlink_ext_ack *extack)
 {
 	struct dsmark_qdisc_data *p = qdisc_priv(sch);

 	return p->block;
 }

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

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

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

 	if (p->set_tc_index) {
 		int wlen = skb_network_offset(skb);

 		switch (skb_protocol(skb, true)) {
 		case htons(ETH_P_IP):
 			wlen += sizeof(struct iphdr);
 			if (!pskb_may_pull(skb, wlen) ||
 			    skb_try_make_writable(skb, wlen))
 				goto drop;

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

 		case htons(ETH_P_IPV6):
 			wlen += sizeof(struct ipv6hdr);
 			if (!pskb_may_pull(skb, wlen) ||
 			    skb_try_make_writable(skb, wlen))
 				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;
 		struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
 		int result = tcf_classify(skb, fl, &res, false);

 		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:
 		case TC_ACT_TRAP:
 			__qdisc_drop(skb, to_free);
 			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, to_free);
 	if (err != NET_XMIT_SUCCESS) {
 		if (net_xmit_drop_count(err))
 			qdisc_qstats_drop(sch);
 		return err;
 	}

 	sch->qstats.backlog += len;
 	sch->q.qlen++;

 	return NET_XMIT_SUCCESS;

 drop:
 	qdisc_drop(skb, sch, to_free);
 	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("%s(sch %p,[qdisc %p])\n", __func__, sch, p);

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

 	qdisc_bstats_update(sch, skb);
 	qdisc_qstats_backlog_dec(sch, skb);
 	sch->q.qlen--;

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

 	switch (skb_protocol(skb, true)) {
 	case htons(ETH_P_IP):
 		ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,
 				    p->mv[index].value);
 			break;
 	case htons(ETH_P_IPV6):
 		ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,
 				    p->mv[index].value);
 			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->mv[index].mask != 0xff || p->mv[index].value)
 			pr_warn("%s: unsupported protocol %d\n",
 				__func__, ntohs(skb_protocol(skb, true)));
 		break;
 	}

 	return skb;
 }

 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 {
 	struct dsmark_qdisc_data *p = qdisc_priv(sch);

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

 	return p->q->ops->peek(p->q);
 }

 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt,
 		       struct netlink_ext_ack *extack)
 {
 	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;
 	int i;

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

 	if (!opt)
 		goto errout;

 	err = tcf_block_get(&p->block, &p->filter_list, sch, extack);
 	if (err)
 		return err;

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

 	err = -EINVAL;
 	if (!tb[TCA_DSMARK_INDICES])
 		goto errout;
 	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]);

 	if (indices <= DSMARK_EMBEDDED_SZ)
 		p->mv = p->embedded;
 	else
 		p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);
 	if (!p->mv) {
 		err = -ENOMEM;
 		goto errout;
 	}
 	for (i = 0; i < indices; i++) {
 		p->mv[i].mask = 0xff;
 		p->mv[i].value = 0;
 	}
 	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(sch->dev_queue, &pfifo_qdisc_ops, sch->handle,
 				 NULL);
 	if (p->q == NULL)
 		p->q = &noop_qdisc;
 	else
 		qdisc_hash_add(p->q, true);

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

 	err = 0;
 errout:
 	return err;
 }

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

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

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

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

 	tcf_block_put(p->block);
 	qdisc_put(p->q);
 	if (p->mv != p->embedded)
 		kfree(p->mv);
 }

 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("%s(sch %p,[qdisc %p],class %ld\n", __func__, 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_noflag(skb, TCA_OPTIONS);
 	if (opts == NULL)
 		goto nla_put_failure;
 	if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) ||
 	    nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))
 		goto nla_put_failure;

 	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_noflag(skb, TCA_OPTIONS);
 	if (opts == NULL)
 		goto nla_put_failure;
 	if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
 		goto nla_put_failure;

 	if (p->default_index != NO_DEFAULT_INDEX &&
 	    nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
 		goto nla_put_failure;

 	if (p->set_tc_index &&
 	    nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
 		goto nla_put_failure;

 	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,
 	.find		=	dsmark_find,
 	.change		=	dsmark_change,
 	.delete		=	dsmark_delete,
 	.walk		=	dsmark_walk,
 	.tcf_block	=	dsmark_tcf_block,
 	.bind_tcf	=	dsmark_bind_filter,
 	.unbind_tcf	=	dsmark_unbind_filter,
 	.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,
 	.peek		=	dsmark_peek,
 	.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");
	// SPDX-License-Identifier: GPL-2.0-only
	/* 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/slab.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/pkt_cls.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 mask_value {
	u8 mask;
	u8 value;
	};

	struct dsmark_qdisc_data {
	struct Qdisc *q;
	struct tcf_proto __rcu *filter_list;
	struct tcf_block *block;
	struct mask_value *mv;
	u16 indices;
	u8 set_tc_index;
	u32 default_index; /* index range is 0...0xffff */
	#define DSMARK_EMBEDDED_SZ 16
	struct mask_value embedded[DSMARK_EMBEDDED_SZ];
	};

	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 netlink_ext_ack *extack)
	{
	struct dsmark_qdisc_data *p = qdisc_priv(sch);

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

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

	*old = qdisc_replace(sch, new, &p->q);
	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_find(struct Qdisc *sch, u32 classid)
	{
	return TC_H_MIN(classid) + 1;
	}

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

	return dsmark_find(sch, classid);
	}

	static void dsmark_unbind_filter(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 netlink_ext_ack *extack)
	{
	struct dsmark_qdisc_data *p = qdisc_priv(sch);
	struct nlattr *opt = tca[TCA_OPTIONS];
	struct nlattr *tb[TCA_DSMARK_MAX + 1];
	int err = -EINVAL;

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

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

	if (!opt)
	goto errout;

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

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

	if (tb[TCA_DSMARK_MASK])
	p->mv[*arg - 1].mask = nla_get_u8(tb[TCA_DSMARK_MASK]);

	err = 0;

	errout:
	return err;
	}

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

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

	p->mv[arg - 1].mask = 0xff;
	p->mv[arg - 1].value = 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("%s(sch %p,[qdisc %p],walker %p)\n",
	__func__, sch, p, walker);

	if (walker->stop)
	return;

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

	static struct tcf_block dsmark_tcf_block(struct Qdisc sch, unsigned long cl,
	struct netlink_ext_ack *extack)
	{
	struct dsmark_qdisc_data *p = qdisc_priv(sch);

	return p->block;
	}

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

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

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

	if (p->set_tc_index) {
	int wlen = skb_network_offset(skb);

	switch (skb_protocol(skb, true)) {
	case htons(ETH_P_IP):
	wlen += sizeof(struct iphdr);
	if (!pskb_may_pull(skb, wlen) \|\|
	skb_try_make_writable(skb, wlen))
	goto drop;

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

	case htons(ETH_P_IPV6):
	wlen += sizeof(struct ipv6hdr);
	if (!pskb_may_pull(skb, wlen) \|\|
	skb_try_make_writable(skb, wlen))
	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;
	struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
	int result = tcf_classify(skb, fl, &res, false);

	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:
	case TC_ACT_TRAP:
	__qdisc_drop(skb, to_free);
	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, to_free);
	if (err != NET_XMIT_SUCCESS) {
	if (net_xmit_drop_count(err))
	qdisc_qstats_drop(sch);
	return err;
	}

	sch->qstats.backlog += len;
	sch->q.qlen++;

	return NET_XMIT_SUCCESS;

	drop:
	qdisc_drop(skb, sch, to_free);
	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("%s(sch %p,[qdisc %p])\n", __func__, sch, p);

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

	qdisc_bstats_update(sch, skb);
	qdisc_qstats_backlog_dec(sch, skb);
	sch->q.qlen--;

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

	switch (skb_protocol(skb, true)) {
	case htons(ETH_P_IP):
	ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,
	p->mv[index].value);
	break;
	case htons(ETH_P_IPV6):
	ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,
	p->mv[index].value);
	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->mv[index].mask != 0xff \|\| p->mv[index].value)
	pr_warn("%s: unsupported protocol %d\n",
	__func__, ntohs(skb_protocol(skb, true)));
	break;
	}

	return skb;
	}

	static struct sk_buff dsmark_peek(struct Qdisc sch)
	{
	struct dsmark_qdisc_data *p = qdisc_priv(sch);

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

	return p->q->ops->peek(p->q);
	}

	static int dsmark_init(struct Qdisc sch, struct nlattr opt,
	struct netlink_ext_ack *extack)
	{
	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;
	int i;

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

	if (!opt)
	goto errout;

	err = tcf_block_get(&p->block, &p->filter_list, sch, extack);
	if (err)
	return err;

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

	err = -EINVAL;
	if (!tb[TCA_DSMARK_INDICES])
	goto errout;
	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]);

	if (indices <= DSMARK_EMBEDDED_SZ)
	p->mv = p->embedded;
	else
	p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);
	if (!p->mv) {
	err = -ENOMEM;
	goto errout;
	}
	for (i = 0; i < indices; i++) {
	p->mv[i].mask = 0xff;
	p->mv[i].value = 0;
	}
	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(sch->dev_queue, &pfifo_qdisc_ops, sch->handle,
	NULL);
	if (p->q == NULL)
	p->q = &noop_qdisc;
	else
	qdisc_hash_add(p->q, true);

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

	err = 0;
	errout:
	return err;
	}

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

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

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

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

	tcf_block_put(p->block);
	qdisc_put(p->q);
	if (p->mv != p->embedded)
	kfree(p->mv);
	}

	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("%s(sch %p,[qdisc %p],class %ld\n", __func__, 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_noflag(skb, TCA_OPTIONS);
	if (opts == NULL)
	goto nla_put_failure;
	if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) \|\|
	nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))
	goto nla_put_failure;

	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_noflag(skb, TCA_OPTIONS);
	if (opts == NULL)
	goto nla_put_failure;
	if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
	goto nla_put_failure;

	if (p->default_index != NO_DEFAULT_INDEX &&
	nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
	goto nla_put_failure;

	if (p->set_tc_index &&
	nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
	goto nla_put_failure;

	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,
	.find = dsmark_find,
	.change = dsmark_change,
	.delete = dsmark_delete,
	.walk = dsmark_walk,
	.tcf_block = dsmark_tcf_block,
	.bind_tcf = dsmark_bind_filter,
	.unbind_tcf = dsmark_unbind_filter,
	.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,
	.peek = dsmark_peek,
	.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");