text: /* net/sched/sch_dsmark.c - Differentiated Services field marker */
  
  /* Written 1998-2000 by Werner Almesberger, EPFL ICA */
  
  
  #include <linux/config.h>
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/string.h>
  #include <linux/errno.h>
  #include <linux/skbuff.h>
  #include <linux/netdevice.h> /* for pkt_sched */
  #include <linux/rtnetlink.h>
  #include <net/pkt_sched.h>
  #include <net/dsfield.h>
  #include <net/inet_ecn.h>
  #include <asm/byteorder.h>
  
  
  #if 1 /* control */
  #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
  #else
  #define DPRINTK(format,args...)
  #endif
  
  #if 0 /* data */
  #define D2PRINTK(format,args...) printk(KERN_DEBUG format,##args)
  #else
  #define D2PRINTK(format,args...)
  #endif
  
  
  #define PRIV(sch) ((struct dsmark_qdisc_data *) (sch)->data)
  
  
  /*
   * 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;
  };
  
  
  /* ------------------------- Class/flow operations ------------------------- */
  
  
  static int dsmark_graft(struct Qdisc *sch,unsigned long arg,
      struct Qdisc *new,struct Qdisc **old)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  
  	DPRINTK("dsmark_graft(sch %p,[qdisc %p],new %p,old %p)\n",sch,p,new,
  	    old);
  	if (!new)
  		new = &noop_qdisc;
  	sch_tree_lock(sch);
  	*old = xchg(&p->q,new);
  	if (*old)
  		qdisc_reset(*old);
  	sch->q.qlen = 0;
  	sch_tree_unlock(sch); /* @@@ move up ? */
          return 0;
  }
  
  
  static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  
  	return p->q;
  }
  
  
  static unsigned long dsmark_get(struct Qdisc *sch,u32 classid)
  {
  	struct dsmark_qdisc_data *p __attribute__((unused)) = PRIV(sch);
  
  	DPRINTK("dsmark_get(sch %p,[qdisc %p],classid %x)\n",sch,p,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 int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
      struct rtattr **tca, unsigned long *arg)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  	struct rtattr *opt = tca[TCA_OPTIONS-1];
  	struct rtattr *tb[TCA_DSMARK_MAX];
  
  	DPRINTK("dsmark_change(sch %p,[qdisc %p],classid %x,parent %x),"
  	    "arg 0x%lx\n",sch,p,classid,parent,*arg);
  	if (*arg > p->indices)
  		return -ENOENT;
  	if (!opt || rtattr_parse(tb, TCA_DSMARK_MAX, RTA_DATA(opt),
  				 RTA_PAYLOAD(opt)))
  		return -EINVAL;
  	if (tb[TCA_DSMARK_MASK-1]) {
  		if (!RTA_PAYLOAD(tb[TCA_DSMARK_MASK-1]))
  			return -EINVAL;
  		p->mask[*arg-1] = *(__u8 *) RTA_DATA(tb[TCA_DSMARK_MASK-1]);
  	}
  	if (tb[TCA_DSMARK_VALUE-1]) {
  		if (!RTA_PAYLOAD(tb[TCA_DSMARK_VALUE-1]))
  			return -EINVAL;
  		p->value[*arg-1] = *(__u8 *) RTA_DATA(tb[TCA_DSMARK_VALUE-1]);
  	}
  	return 0;
  }
  
  
  static int dsmark_delete(struct Qdisc *sch,unsigned long arg)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  
  	if (!arg || arg > p->indices)
  		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 = PRIV(sch);
  	int i;
  
  	DPRINTK("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])
  			continue;
  		if (walker->count >= walker->skip) {
  			if (walker->fn(sch, i+1, walker) < 0) {
  				walker->stop = 1;
  				break;
  			}
  		}
                  walker->count++;
          }
  }
  
  
  static struct tcf_proto **dsmark_find_tcf(struct Qdisc *sch,unsigned long cl)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  
  	return &p->filter_list;
  }
  
  
  /* --------------------------- Qdisc operations ---------------------------- */
  
  
  static int dsmark_enqueue(struct sk_buff *skb,struct Qdisc *sch)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  	struct tcf_result res;
  	int result;
  	int ret = NET_XMIT_POLICED;
  
  	D2PRINTK("dsmark_enqueue(skb %p,sch %p,[qdisc %p])\n",skb,sch,p);
  	if (p->set_tc_index) {
  		switch (skb->protocol) {
  			case __constant_htons(ETH_P_IP):
  				skb->tc_index = ipv4_get_dsfield(skb->nh.iph)
  					& ~INET_ECN_MASK;
  				break;
  			case __constant_htons(ETH_P_IPV6):
  				skb->tc_index = ipv6_get_dsfield(skb->nh.ipv6h)
  					& ~INET_ECN_MASK;
  				break;
  			default:
  				skb->tc_index = 0;
  				break;
  		};
  	}
  	result = TC_POLICE_OK; /* be nice to gcc */
  	if (TC_H_MAJ(skb->priority) == sch->handle) {
  		skb->tc_index = TC_H_MIN(skb->priority);
  	} else {
  		result = tc_classify(skb,p->filter_list,&res);
  		D2PRINTK("result %d class 0x%04x\n",result,res.classid);
  		switch (result) {
  #ifdef CONFIG_NET_CLS_POLICE
  			case TC_POLICE_SHOT:
  				kfree_skb(skb);
  				break;
  #if 0
  			case TC_POLICE_RECLASSIFY:
  				/* FIXME: what to do here ??? */
  #endif
  #endif
  			case TC_POLICE_OK:
  				skb->tc_index = TC_H_MIN(res.classid);
  				break;
  			case TC_POLICE_UNSPEC:
  				/* fall through */
  			default:
  				if (p->default_index != NO_DEFAULT_INDEX)
  					skb->tc_index = p->default_index;
  				break;
  		};
  	}
  	if (
  #ifdef CONFIG_NET_CLS_POLICE
  	    result == TC_POLICE_SHOT ||
  #endif
  
  	    ((ret = p->q->enqueue(skb,p->q)) != 0)) {
  		sch->stats.drops++;
  		return ret;
  	}
  	sch->stats.bytes += skb->len;
  	sch->stats.packets++;
  	sch->q.qlen++;
  	return ret;
  }
  
  
  static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  	struct sk_buff *skb;
  	int index;
  
  	D2PRINTK("dsmark_dequeue(sch %p,[qdisc %p])\n",sch,p);
  	skb = p->q->ops->dequeue(p->q);
  	if (!skb)
  		return NULL;
  	sch->q.qlen--;
  	index = skb->tc_index & (p->indices-1);
  	D2PRINTK("index %d->%d\n",skb->tc_index,index);
  	switch (skb->protocol) {
  		case __constant_htons(ETH_P_IP):
  			ipv4_change_dsfield(skb->nh.iph,
  			    p->mask[index],p->value[index]);
  			break;
  		case __constant_htons(ETH_P_IPV6):
  			ipv6_change_dsfield(skb->nh.ipv6h,
  			    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",
  				       htons(skb->protocol));
  			break;
  	};
  	return skb;
  }
  
  
  static int dsmark_requeue(struct sk_buff *skb,struct Qdisc *sch)
  {
  	int ret;
  	struct dsmark_qdisc_data *p = PRIV(sch);
  
  	D2PRINTK("dsmark_requeue(skb %p,sch %p,[qdisc %p])\n",skb,sch,p);
          if ((ret = p->q->ops->requeue(skb, p->q)) == 0) {
  		sch->q.qlen++;
  		return 0;
  	}
  	sch->stats.drops++;
  	return ret;
  }
  
  
  static unsigned int dsmark_drop(struct Qdisc *sch)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  	unsigned int len;
  	
  	DPRINTK("dsmark_reset(sch %p,[qdisc %p])\n",sch,p);
  	if (!p->q->ops->drop)
  		return 0;
  	if (!(len = p->q->ops->drop(p->q)))
  		return 0;
  	sch->q.qlen--;
  	return len;
  }
  
  
  int dsmark_init(struct Qdisc *sch,struct rtattr *opt)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  	struct rtattr *tb[TCA_DSMARK_MAX];
  	__u16 tmp;
  
  	DPRINTK("dsmark_init(sch %p,[qdisc %p],opt %p)\n",sch,p,opt);
  	if (!opt ||
  	    rtattr_parse(tb,TCA_DSMARK_MAX,RTA_DATA(opt),RTA_PAYLOAD(opt)) < 0 ||
  	    !tb[TCA_DSMARK_INDICES-1] ||
  	    RTA_PAYLOAD(tb[TCA_DSMARK_INDICES-1]) < sizeof(__u16))
                  return -EINVAL;
  	p->indices = *(__u16 *) RTA_DATA(tb[TCA_DSMARK_INDICES-1]);
  	if (!p->indices)
  		return -EINVAL;
  	for (tmp = p->indices; tmp != 1; tmp >>= 1) {
  		if (tmp & 1)
  			return -EINVAL;
  	}
  	p->default_index = NO_DEFAULT_INDEX;
  	if (tb[TCA_DSMARK_DEFAULT_INDEX-1]) {
  		if (RTA_PAYLOAD(tb[TCA_DSMARK_DEFAULT_INDEX-1]) < sizeof(__u16))
  			return -EINVAL;
  		p->default_index =
  		    *(__u16 *) RTA_DATA(tb[TCA_DSMARK_DEFAULT_INDEX-1]);
  	}
  	p->set_tc_index = !!tb[TCA_DSMARK_SET_TC_INDEX-1];
  	p->mask = kmalloc(p->indices*2,GFP_KERNEL);
  	if (!p->mask)
  		return -ENOMEM;
  	p->value = p->mask+p->indices;
  	memset(p->mask,0xff,p->indices);
  	memset(p->value,0,p->indices);
  	if (!(p->q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops)))
  		p->q = &noop_qdisc;
  	DPRINTK("dsmark_init: qdisc %p\n",&p->q);
  	MOD_INC_USE_COUNT;
  	return 0;
  }
  
  
  static void dsmark_reset(struct Qdisc *sch)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  
  	DPRINTK("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 = PRIV(sch);
  	struct tcf_proto *tp;
  
  	DPRINTK("dsmark_destroy(sch %p,[qdisc %p])\n",sch,p);
  	while (p->filter_list) {
  		tp = p->filter_list;
  		p->filter_list = tp->next;
  		tcf_destroy(tp);
  	}
  	qdisc_destroy(p->q);
  	p->q = &noop_qdisc;
  	kfree(p->mask);
  	MOD_DEC_USE_COUNT;
  }
  
  
  static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
      struct sk_buff *skb, struct tcmsg *tcm)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  	unsigned char *b = skb->tail;
  	struct rtattr *rta;
  
  	DPRINTK("dsmark_dump_class(sch %p,[qdisc %p],class %ld\n",sch,p,cl);
  	if (!cl || cl > p->indices)
  		return -EINVAL;
  	tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle),cl-1);
  	rta = (struct rtattr *) b;
  	RTA_PUT(skb,TCA_OPTIONS,0,NULL);
  	RTA_PUT(skb,TCA_DSMARK_MASK,1,&p->mask[cl-1]);
  	RTA_PUT(skb,TCA_DSMARK_VALUE,1,&p->value[cl-1]);
  	rta->rta_len = skb->tail-b;
  	return skb->len;
  
  rtattr_failure:
  	skb_trim(skb,b-skb->data);
  	return -1;
  }
  
  static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
  {
  	struct dsmark_qdisc_data *p = PRIV(sch);
  	unsigned char *b = skb->tail;
  	struct rtattr *rta;
  
  	rta = (struct rtattr *) b;
  	RTA_PUT(skb,TCA_OPTIONS,0,NULL);
  	RTA_PUT(skb,TCA_DSMARK_INDICES,sizeof(__u16),&p->indices);
  	if (p->default_index != NO_DEFAULT_INDEX) {
  		__u16 tmp = p->default_index;
  
  		RTA_PUT(skb,TCA_DSMARK_DEFAULT_INDEX, sizeof(__u16), &tmp);
  	}
  	if (p->set_tc_index)
  		RTA_PUT(skb, TCA_DSMARK_SET_TC_INDEX, 0, NULL);
  	rta->rta_len = skb->tail-b;
  	return skb->len;
  
  rtattr_failure:
  	skb_trim(skb,b-skb->data);
  	return -1;
  }
  
  static struct Qdisc_class_ops dsmark_class_ops =
  {
  	dsmark_graft,			/* graft */
  	dsmark_leaf,			/* leaf */
  	dsmark_get,			/* get */
  	dsmark_put,			/* put */
  	dsmark_change,			/* change */
  	dsmark_delete,			/* delete */
  	dsmark_walk,			/* walk */
  
  	dsmark_find_tcf,		/* tcf_chain */
  	dsmark_bind_filter,		/* bind_tcf */
  	dsmark_put,			/* unbind_tcf */
  
  	dsmark_dump_class,		/* dump */
  };
  
  struct Qdisc_ops dsmark_qdisc_ops =
  {
  	NULL,				/* next */
  	&dsmark_class_ops,		/* cl_ops */
  	"dsmark",
  	sizeof(struct dsmark_qdisc_data),
  
  	dsmark_enqueue,			/* enqueue */
  	dsmark_dequeue,			/* dequeue */
  	dsmark_requeue,			/* requeue */
  	dsmark_drop,			/* drop */
  
  	dsmark_init,			/* init */
  	dsmark_reset,			/* reset */
  	dsmark_destroy,			/* destroy */
  	NULL,				/* change */
  
  	dsmark_dump			/* dump */
  };
  
  #ifdef MODULE
  int init_module(void)
  {
  	return register_qdisc(&dsmark_qdisc_ops);
  }
  
  
  void cleanup_module(void) 
  {
  	unregister_qdisc(&dsmark_qdisc_ops);
  }
  #endif
  MODULE_LICENSE("GPL");
  