sch_api.c

Linux Kernel 2.6.9 for OMAP1710

	struct Qdisc *q = NULL;
	struct Qdisc *p = NULL;
	int err;

	if ((dev = __dev_get_by_index(tcm->tcm_ifindex)) == NULL)
		return -ENODEV;

	if (clid) {
		if (clid != TC_H_ROOT) {
			if (clid != TC_H_INGRESS) {
				if ((p = qdisc_lookup(dev, TC_H_MAJ(clid))) == NULL)
					return -ENOENT;
				q = qdisc_leaf(p, clid);
			} else { /*ingress */
				q = dev->qdisc_ingress;
			}
		} else {
			q = dev->qdisc_sleeping;
		}

		/* It may be default qdisc, ignore it */
		if (q && q->handle == 0)
			q = NULL;

		if (!q || !tcm->tcm_handle || q->handle != tcm->tcm_handle) {
			if (tcm->tcm_handle) {
				if (q && !(n->nlmsg_flags&NLM_F_REPLACE))
					return -EEXIST;
				if (TC_H_MIN(tcm->tcm_handle))
					return -EINVAL;
				if ((q = qdisc_lookup(dev, tcm->tcm_handle)) == NULL)
					goto create_n_graft;
				if (n->nlmsg_flags&NLM_F_EXCL)
					return -EEXIST;
				if (tca[TCA_KIND-1] && rtattr_strcmp(tca[TCA_KIND-1], q->ops->id))
					return -EINVAL;
				if (q == p ||
				    (p && check_loop(q, p, 0)))
					return -ELOOP;
				atomic_inc(&q->refcnt);
				goto graft;
			} else {
				if (q == NULL)
					goto create_n_graft;

				/* This magic test requires explanation.
				 *
				 *   We know, that some child q is already
				 *   attached to this parent and have choice:
				 *   either to change it or to create/graft new one.
				 *
				 *   1. We are allowed to create/graft only
				 *   if CREATE and REPLACE flags are set.
				 *
				 *   2. If EXCL is set, requestor wanted to say,
				 *   that qdisc tcm_handle is not expected
				 *   to exist, so that we choose create/graft too.
				 *
				 *   3. The last case is when no flags are set.
				 *   Alas, it is sort of hole in API, we
				 *   cannot decide what to do unambiguously.
				 *   For now we select create/graft, if
				 *   user gave KIND, which does not match existing.
				 */
				if ((n->nlmsg_flags&NLM_F_CREATE) &&
				    (n->nlmsg_flags&NLM_F_REPLACE) &&
				    ((n->nlmsg_flags&NLM_F_EXCL) ||
				     (tca[TCA_KIND-1] &&
				      rtattr_strcmp(tca[TCA_KIND-1], q->ops->id))))
					goto create_n_graft;
			}
		}
	} else {
		if (!tcm->tcm_handle)
			return -EINVAL;
		q = qdisc_lookup(dev, tcm->tcm_handle);
	}

	/* Change qdisc parameters */
	if (q == NULL)
		return -ENOENT;
	if (n->nlmsg_flags&NLM_F_EXCL)
		return -EEXIST;
	if (tca[TCA_KIND-1] && rtattr_strcmp(tca[TCA_KIND-1], q->ops->id))
		return -EINVAL;
	err = qdisc_change(q, tca);
	if (err == 0)
		qdisc_notify(skb, n, clid, NULL, q);
	return err;

create_n_graft:
	if (!(n->nlmsg_flags&NLM_F_CREATE))
		return -ENOENT;
	if (clid == TC_H_INGRESS)
		q = qdisc_create(dev, tcm->tcm_parent, tca, &err);
        else
		q = qdisc_create(dev, tcm->tcm_handle, tca, &err);
	if (q == NULL)
		return err;

graft:
	if (1) {
		struct Qdisc *old_q = NULL;
		err = qdisc_graft(dev, p, clid, q, &old_q);
		if (err) {
			if (q) {
				spin_lock_bh(&dev->queue_lock);
				qdisc_destroy(q);
				spin_unlock_bh(&dev->queue_lock);
			}
			return err;
		}
		qdisc_notify(skb, n, clid, old_q, q);
		if (old_q) {
			spin_lock_bh(&dev->queue_lock);
			qdisc_destroy(old_q);
			spin_unlock_bh(&dev->queue_lock);
		}
	}
	return 0;
}

int qdisc_copy_stats(struct sk_buff *skb, struct tc_stats *st, spinlock_t *lock)
{
	spin_lock_bh(lock);
	RTA_PUT(skb, TCA_STATS, sizeof(struct tc_stats), st);
	spin_unlock_bh(lock);
	return 0;

rtattr_failure:
	spin_unlock_bh(lock);
	return -1;
}


static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
			 u32 pid, u32 seq, unsigned flags, int event)
{
	struct tcmsg *tcm;
	struct nlmsghdr  *nlh;
	unsigned char	 *b = skb->tail;

	nlh = NLMSG_PUT(skb, pid, seq, event, sizeof(*tcm));
	nlh->nlmsg_flags = flags;
	tcm = NLMSG_DATA(nlh);
	tcm->tcm_family = AF_UNSPEC;
	tcm->tcm_ifindex = q->dev->ifindex;
	tcm->tcm_parent = clid;
	tcm->tcm_handle = q->handle;
	tcm->tcm_info = atomic_read(&q->refcnt);
	RTA_PUT(skb, TCA_KIND, IFNAMSIZ, q->ops->id);
	if (q->ops->dump && q->ops->dump(q, skb) < 0)
		goto rtattr_failure;
	q->stats.qlen = q->q.qlen;
	if (qdisc_copy_stats(skb, &q->stats, q->stats_lock))
		goto rtattr_failure;
	nlh->nlmsg_len = skb->tail - b;
	return skb->len;

nlmsg_failure:
rtattr_failure:
	skb_trim(skb, b - skb->data);
	return -1;
}

static int qdisc_notify(struct sk_buff *oskb, struct nlmsghdr *n,
			u32 clid, struct Qdisc *old, struct Qdisc *new)
{
	struct sk_buff *skb;
	u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	if (old && old->handle) {
		if (tc_fill_qdisc(skb, old, clid, pid, n->nlmsg_seq, 0, RTM_DELQDISC) < 0)
			goto err_out;
	}
	if (new) {
		if (tc_fill_qdisc(skb, new, clid, pid, n->nlmsg_seq, old ? NLM_F_REPLACE : 0, RTM_NEWQDISC) < 0)
			goto err_out;
	}

	if (skb->len)
		return rtnetlink_send(skb, pid, RTMGRP_TC, n->nlmsg_flags&NLM_F_ECHO);

err_out:
	kfree_skb(skb);
	return -EINVAL;
}

static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
{
	int idx, q_idx;
	int s_idx, s_q_idx;
	struct net_device *dev;
	struct Qdisc *q;

	s_idx = cb->args[0];
	s_q_idx = q_idx = cb->args[1];
	read_lock(&dev_base_lock);
	for (dev=dev_base, idx=0; dev; dev = dev->next, idx++) {
		if (idx < s_idx)
			continue;
		if (idx > s_idx)
			s_q_idx = 0;
		read_lock_bh(&qdisc_tree_lock);
		q_idx = 0;
		list_for_each_entry(q, &dev->qdisc_list, list) {
			if (q_idx < s_q_idx) {
				q_idx++;
				continue;
			}
			if (tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).pid,
					  cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWQDISC) <= 0) {
				read_unlock_bh(&qdisc_tree_lock);
				goto done;
			}
			q_idx++;
		}
		read_unlock_bh(&qdisc_tree_lock);
	}

done:
	read_unlock(&dev_base_lock);

	cb->args[0] = idx;
	cb->args[1] = q_idx;

	return skb->len;
}



/************************************************
 *	Traffic classes manipulation.		*
 ************************************************/



static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
{
	struct tcmsg *tcm = NLMSG_DATA(n);
	struct rtattr **tca = arg;
	struct net_device *dev;
	struct Qdisc *q = NULL;
	struct Qdisc_class_ops *cops;
	unsigned long cl = 0;
	unsigned long new_cl;
	u32 pid = tcm->tcm_parent;
	u32 clid = tcm->tcm_handle;
	u32 qid = TC_H_MAJ(clid);
	int err;

	if ((dev = __dev_get_by_index(tcm->tcm_ifindex)) == NULL)
		return -ENODEV;

	/*
	   parent == TC_H_UNSPEC - unspecified parent.
	   parent == TC_H_ROOT   - class is root, which has no parent.
	   parent == X:0	 - parent is root class.
	   parent == X:Y	 - parent is a node in hierarchy.
	   parent == 0:Y	 - parent is X:Y, where X:0 is qdisc.

	   handle == 0:0	 - generate handle from kernel pool.
	   handle == 0:Y	 - class is X:Y, where X:0 is qdisc.
	   handle == X:Y	 - clear.
	   handle == X:0	 - root class.
	 */

	/* Step 1. Determine qdisc handle X:0 */

	if (pid != TC_H_ROOT) {
		u32 qid1 = TC_H_MAJ(pid);

		if (qid && qid1) {
			/* If both majors are known, they must be identical. */
			if (qid != qid1)
				return -EINVAL;
		} else if (qid1) {
			qid = qid1;
		} else if (qid == 0)
			qid = dev->qdisc_sleeping->handle;

		/* Now qid is genuine qdisc handle consistent
		   both with parent and child.

		   TC_H_MAJ(pid) still may be unspecified, complete it now.
		 */
		if (pid)
			pid = TC_H_MAKE(qid, pid);
	} else {
		if (qid == 0)
			qid = dev->qdisc_sleeping->handle;
	}

	/* OK. Locate qdisc */
	if ((q = qdisc_lookup(dev, qid)) == NULL) 
		return -ENOENT;

	/* An check that it supports classes */
	cops = q->ops->cl_ops;
	if (cops == NULL)
		return -EINVAL;

	/* Now try to get class */
	if (clid == 0) {
		if (pid == TC_H_ROOT)
			clid = qid;
	} else
		clid = TC_H_MAKE(qid, clid);

	if (clid)
		cl = cops->get(q, clid);

	if (cl == 0) {
		err = -ENOENT;
		if (n->nlmsg_type != RTM_NEWTCLASS || !(n->nlmsg_flags&NLM_F_CREATE))
			goto out;
	} else {
		switch (n->nlmsg_type) {
		case RTM_NEWTCLASS:	
			err = -EEXIST;
			if (n->nlmsg_flags&NLM_F_EXCL)
				goto out;
			break;
		case RTM_DELTCLASS:
			err = cops->delete(q, cl);
			if (err == 0)
				tclass_notify(skb, n, q, cl, RTM_DELTCLASS);
			goto out;
		case RTM_GETTCLASS:
			err = tclass_notify(skb, n, q, cl, RTM_NEWTCLASS);
			goto out;
		default:
			err = -EINVAL;
			goto out;
		}
	}

	new_cl = cl;
	err = cops->change(q, clid, pid, tca, &new_cl);
	if (err == 0)
		tclass_notify(skb, n, q, new_cl, RTM_NEWTCLASS);

out:
	if (cl)
		cops->put(q, cl);

	return err;
}


static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
			  unsigned long cl,
			  u32 pid, u32 seq, unsigned flags, int event)
{
	struct tcmsg *tcm;
	struct nlmsghdr  *nlh;
	unsigned char	 *b = skb->tail;

	nlh = NLMSG_PUT(skb, pid, seq, event, sizeof(*tcm));
	nlh->nlmsg_flags = flags;
	tcm = NLMSG_DATA(nlh);
	tcm->tcm_family = AF_UNSPEC;
	tcm->tcm_ifindex = q->dev->ifindex;
	tcm->tcm_parent = q->handle;
	tcm->tcm_handle = q->handle;
	tcm->tcm_info = 0;
	RTA_PUT(skb, TCA_KIND, IFNAMSIZ, q->ops->id);
	if (q->ops->cl_ops->dump && q->ops->cl_ops->dump(q, cl, skb, tcm) < 0)
		goto rtattr_failure;
	nlh->nlmsg_len = skb->tail - b;
	return skb->len;

nlmsg_failure:
rtattr_failure:
	skb_trim(skb, b - skb->data);
	return -1;
}

static int tclass_notify(struct sk_buff *oskb, struct nlmsghdr *n,
			  struct Qdisc *q, unsigned long cl, int event)
{
	struct sk_buff *skb;
	u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	if (tc_fill_tclass(skb, q, cl, pid, n->nlmsg_seq, 0, event) < 0) {
		kfree_skb(skb);
		return -EINVAL;
	}

	return rtnetlink_send(skb, pid, RTMGRP_TC, n->nlmsg_flags&NLM_F_ECHO);
}

struct qdisc_dump_args
{
	struct qdisc_walker w;
	struct sk_buff *skb;
	struct netlink_callback *cb;
};

static int qdisc_class_dump(struct Qdisc *q, unsigned long cl, struct qdisc_walker *arg)
{
	struct qdisc_dump_args *a = (struct qdisc_dump_args *)arg;

	return tc_fill_tclass(a->skb, q, cl, NETLINK_CB(a->cb->skb).pid,
			      a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTCLASS);
}

static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
{
	int t;
	int s_t;
	struct net_device *dev;
	struct Qdisc *q;
	struct tcmsg *tcm = (struct tcmsg*)NLMSG_DATA(cb->nlh);
	struct qdisc_dump_args arg;

	if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
		return 0;
	if ((dev = dev_get_by_index(tcm->tcm_ifindex)) == NULL)
		return 0;

	s_t = cb->args[0];
	t = 0;

	read_lock_bh(&qdisc_tree_lock);
	list_for_each_entry(q, &dev->qdisc_list, list) {
		if (t < s_t || !q->ops->cl_ops ||
		    (tcm->tcm_parent &&
		     TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
			t++;
			continue;
		}
		if (t > s_t)
			memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
		arg.w.fn = qdisc_class_dump;
		arg.skb = skb;
		arg.cb = cb;
		arg.w.stop  = 0;
		arg.w.skip = cb->args[1];
		arg.w.count = 0;
		q->ops->cl_ops->walk(q, &arg.w);
		cb->args[1] = arg.w.count;
		if (arg.w.stop)
			break;
		t++;
	}
	read_unlock_bh(&qdisc_tree_lock);

	cb->args[0] = t;

	dev_put(dev);
	return skb->len;
}

int psched_us_per_tick = 1;
int psched_tick_per_us = 1;

#ifdef CONFIG_PROC_FS
static int psched_show(struct seq_file *seq, void *v)
{
	seq_printf(seq, "%08x %08x %08x %08x\n",
		      psched_tick_per_us, psched_us_per_tick,
		      1000000, HZ);

	return 0;
}

static int psched_open(struct inode *inode, struct file *file)
{
	return single_open(file, psched_show, PDE(inode)->data);
}

static struct file_operations psched_fops = {
	.owner = THIS_MODULE,
	.open = psched_open,
	.read  = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};	
#endif

#ifdef CONFIG_NET_SCH_CLK_GETTIMEOFDAY
int psched_tod_diff(int delta_sec, int bound)
{
	int delta;

	if (bound <= 1000000 || delta_sec > (0x7FFFFFFF/1000000)-1)
		return bound;
	delta = delta_sec * 1000000;
	if (delta > bound)
		delta = bound;
	return delta;
}
EXPORT_SYMBOL(psched_tod_diff);
#endif

#ifdef CONFIG_NET_SCH_CLK_CPU
psched_tdiff_t psched_clock_per_hz;
int psched_clock_scale;
EXPORT_SYMBOL(psched_clock_per_hz);
EXPORT_SYMBOL(psched_clock_scale);

psched_time_t psched_time_base;
cycles_t psched_time_mark;
EXPORT_SYMBOL(psched_time_mark);
EXPORT_SYMBOL(psched_time_base);

/*
 * Periodically adjust psched_time_base to avoid overflow
 * with 32-bit get_cycles(). Safe up to 4GHz CPU.
 */
static void psched_tick(unsigned long);
static struct timer_list psched_timer = TIMER_INITIALIZER(psched_tick, 0, 0);

static void psched_tick(unsigned long dummy)
{
	if (sizeof(cycles_t) == sizeof(u32)) {
		psched_time_t dummy_stamp;
		PSCHED_GET_TIME(dummy_stamp);
		psched_timer.expires = jiffies + 1*HZ;
		add_timer(&psched_timer);
	}
}

int __init psched_calibrate_clock(void)
{
	psched_time_t stamp, stamp1;
	struct timeval tv, tv1;
	psched_tdiff_t delay;
	long rdelay;
	unsigned long stop;

	psched_tick(0);
	stop = jiffies + HZ/10;
	PSCHED_GET_TIME(stamp);
	do_gettimeofday(&tv);
	while (time_before(jiffies, stop)) {
		barrier();
		cpu_relax();
	}
	PSCHED_GET_TIME(stamp1);
	do_gettimeofday(&tv1);

	delay = PSCHED_TDIFF(stamp1, stamp);
	rdelay = tv1.tv_usec - tv.tv_usec;
	rdelay += (tv1.tv_sec - tv.tv_sec)*1000000;
	if (rdelay > delay)
		return -1;
	delay /= rdelay;
	psched_tick_per_us = delay;
	while ((delay>>=1) != 0)
		psched_clock_scale++;
	psched_us_per_tick = 1<<psched_clock_scale;
	psched_clock_per_hz = (psched_tick_per_us*(1000000/HZ))>>psched_clock_scale;
	return 0;
}
#endif

static int __init pktsched_init(void)
{
	struct rtnetlink_link *link_p;

#ifdef CONFIG_NET_SCH_CLK_CPU
	if (psched_calibrate_clock() < 0)
		return -1;
#elif defined(CONFIG_NET_SCH_CLK_JIFFIES)
	psched_tick_per_us = HZ<<PSCHED_JSCALE;
	psched_us_per_tick = 1000000;
#endif

	link_p = rtnetlink_links[PF_UNSPEC];

	/* Setup rtnetlink links. It is made here to avoid
	   exporting large number of public symbols.
	 */

	if (link_p) {
		link_p[RTM_NEWQDISC-RTM_BASE].doit = tc_modify_qdisc;
		link_p[RTM_DELQDISC-RTM_BASE].doit = tc_get_qdisc;
		link_p[RTM_GETQDISC-RTM_BASE].doit = tc_get_qdisc;
		link_p[RTM_GETQDISC-RTM_BASE].dumpit = tc_dump_qdisc;
		link_p[RTM_NEWTCLASS-RTM_BASE].doit = tc_ctl_tclass;
		link_p[RTM_DELTCLASS-RTM_BASE].doit = tc_ctl_tclass;
		link_p[RTM_GETTCLASS-RTM_BASE].doit = tc_ctl_tclass;
		link_p[RTM_GETTCLASS-RTM_BASE].dumpit = tc_dump_tclass;
	}

	register_qdisc(&pfifo_qdisc_ops);
	register_qdisc(&bfifo_qdisc_ops);
	proc_net_fops_create("psched", 0, &psched_fops);

	return 0;
}

subsys_initcall(pktsched_init);

EXPORT_SYMBOL(qdisc_copy_stats);
EXPORT_SYMBOL(qdisc_get_rtab);
EXPORT_SYMBOL(qdisc_put_rtab);
EXPORT_SYMBOL(register_qdisc);
EXPORT_SYMBOL(unregister_qdisc);