/* 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/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)
  ",

  		sch, p, new, old);

  
  	if (new == NULL) {

  		new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,

  					sch->handle);

  		if (new == NULL)
  			new = &noop_qdisc;
  	}

  	sch_tree_lock(sch);

  	*old = p->q;
  	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)
  ",
  		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
  ", 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)
  ", 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])
  ", 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
  ", 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->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])
  ", sch, p);

  	skb = p->q->ops->dequeue(p->q);

  	if (skb == NULL)

  		return NULL;

  	qdisc_bstats_update(sch, skb);

  	sch->q.qlen--;

  
  	index = skb->tc_index & (p->indices - 1);

  	pr_debug("index %d->%d
  ", 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])

  			pr_warning("dsmark_dequeue: unsupported protocol %d
  ",
  				   ntohs(skb->protocol));

  		break;

  	}

  	return skb;
  }

  static struct sk_buff *dsmark_peek(struct Qdisc *sch)
  {
  	struct dsmark_qdisc_data *p = qdisc_priv(sch);
  
  	pr_debug("dsmark_peek(sch %p,[qdisc %p])
  ", sch, p);
  
  	return p->q->ops->peek(p->q);
  }

  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])
  ", 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)
  ", 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(sch->dev_queue, &pfifo_qdisc_ops, sch->handle);

  	if (p->q == NULL)

  		p->q = &noop_qdisc;

  	pr_debug("dsmark_init: qdisc %p
  ", 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])
  ", 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])
  ", 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
  ", 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,

  	.peek		=	dsmark_peek,

  	.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");