Commit c431f89b authored by Vlad Buslov's avatar Vlad Buslov Committed by David S. Miller
Browse files

net: sched: split tc_ctl_tfilter into three handlers 



tc_ctl_tfilter handles three netlink message types: RTM_NEWTFILTER,
RTM_DELTFILTER, RTM_GETTFILTER. However, implementation of this function
involves a lot of branching on specific message type because most of the
code is message-specific. This significantly complicates adding new
functionality and doesn't provide much benefit of code reuse.

Split tc_ctl_tfilter to three standalone functions that handle filter new,
delete and get requests.

The only truly protocol independent part of tc_ctl_tfilter is code that
looks up queue, class, and block. Refactor this code to standalone
tcf_block_find function that is used by all three new handlers.

Signed-off-by: default avatarVlad Buslov <vladbu@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent af066ed3

net/sched/cls_api.c

+293 −145
Original line number Diff line number Diff line
@@ -437,6 +437,78 @@ static struct tcf_block *tcf_block_lookup(struct net *net, u32 block_index) 
	return idr_find(&tn->idr, block_index);

}



/* Find tcf block.

 * Set q, parent, cl when appropriate.

 */



static struct tcf_block *tcf_block_find(struct net *net, struct Qdisc **q,

					u32 *parent, unsigned long *cl,

					int ifindex, u32 block_index,

					struct netlink_ext_ack *extack)

{

	struct tcf_block *block;



	if (ifindex == TCM_IFINDEX_MAGIC_BLOCK) {

		block = tcf_block_lookup(net, block_index);

		if (!block) {

			NL_SET_ERR_MSG(extack, "Block of given index was not found");

			return ERR_PTR(-EINVAL);

		}

	} else {

		const struct Qdisc_class_ops *cops;

		struct net_device *dev;



		/* Find link */

		dev = __dev_get_by_index(net, ifindex);

		if (!dev)

			return ERR_PTR(-ENODEV);



		/* Find qdisc */

		if (!*parent) {

			*q = dev->qdisc;

			*parent = (*q)->handle;

		} else {

			*q = qdisc_lookup(dev, TC_H_MAJ(*parent));

			if (!*q) {

				NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists");

				return ERR_PTR(-EINVAL);

			}

		}



		/* Is it classful? */

		cops = (*q)->ops->cl_ops;

		if (!cops) {

			NL_SET_ERR_MSG(extack, "Qdisc not classful");

			return ERR_PTR(-EINVAL);

		}



		if (!cops->tcf_block) {

			NL_SET_ERR_MSG(extack, "Class doesn't support blocks");

			return ERR_PTR(-EOPNOTSUPP);

		}



		/* Do we search for filter, attached to class? */

		if (TC_H_MIN(*parent)) {

			*cl = cops->find(*q, *parent);

			if (*cl == 0) {

				NL_SET_ERR_MSG(extack, "Specified class doesn't exist");

				return ERR_PTR(-ENOENT);

			}

		}



		/* And the last stroke */

		block = cops->tcf_block(*q, *cl, extack);

		if (!block)

			return ERR_PTR(-EINVAL);

		if (tcf_block_shared(block)) {

			NL_SET_ERR_MSG(extack, "This filter block is shared. Please use the block index to manipulate the filters");

			return ERR_PTR(-EOPNOTSUPP);

		}

	}



	return block;

}



static struct tcf_chain *tcf_block_chain_zero(struct tcf_block *block)

{

	return list_first_entry(&block->chain_list, struct tcf_chain, list);
@@ -984,9 +1056,7 @@ static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb, 
			       q, parent, 0, event, false);

}



/* Add/change/delete/get a filter node */



static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,

static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n,

			  struct netlink_ext_ack *extack)

{

	struct net *net = sock_net(skb->sk);
@@ -1007,8 +1077,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, 
	int err;

	int tp_created;



	if ((n->nlmsg_type != RTM_GETTFILTER) &&

	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))

	if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))

		return -EPERM;



replay:
@@ -1026,24 +1095,13 @@ replay: 
	cl = 0;



	if (prio == 0) {

		switch (n->nlmsg_type) {

		case RTM_DELTFILTER:

			if (protocol || t->tcm_handle || tca[TCA_KIND]) {

				NL_SET_ERR_MSG(extack, "Cannot flush filters with protocol, handle or kind set");

				return -ENOENT;

			}

			break;

		case RTM_NEWTFILTER:

		/* If no priority is provided by the user,

		 * we allocate one.

		 */

		if (n->nlmsg_flags & NLM_F_CREATE) {

			prio = TC_H_MAKE(0x80000000U, 0U);

			prio_allocate = true;

				break;

			}

			/* fall-through */

		default:

		} else {

			NL_SET_ERR_MSG(extack, "Invalid filter command with priority of zero");

			return -ENOENT;

		}
@@ -1051,67 +1109,12 @@ replay: 


	/* Find head of filter chain. */



	if (t->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {

		block = tcf_block_lookup(net, t->tcm_block_index);

		if (!block) {

			NL_SET_ERR_MSG(extack, "Block of given index was not found");

			err = -EINVAL;

			goto errout;

		}

	} else {

		const struct Qdisc_class_ops *cops;

		struct net_device *dev;



		/* Find link */

		dev = __dev_get_by_index(net, t->tcm_ifindex);

		if (!dev)

			return -ENODEV;



		/* Find qdisc */

		if (!parent) {

			q = dev->qdisc;

			parent = q->handle;

		} else {

			q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));

			if (!q) {

				NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists");

				return -EINVAL;

			}

		}



		/* Is it classful? */

		cops = q->ops->cl_ops;

		if (!cops) {

			NL_SET_ERR_MSG(extack, "Qdisc not classful");

			return -EINVAL;

		}



		if (!cops->tcf_block) {

			NL_SET_ERR_MSG(extack, "Class doesn't support blocks");

			return -EOPNOTSUPP;

		}



		/* Do we search for filter, attached to class? */

		if (TC_H_MIN(parent)) {

			cl = cops->find(q, parent);

			if (cl == 0) {

				NL_SET_ERR_MSG(extack, "Specified class doesn't exist");

				return -ENOENT;

			}

		}



		/* And the last stroke */

		block = cops->tcf_block(q, cl, extack);

		if (!block) {

			err = -EINVAL;

	block = tcf_block_find(net, &q, &parent, &cl,

			       t->tcm_ifindex, t->tcm_block_index, extack);

	if (IS_ERR(block)) {

		err = PTR_ERR(block);

		goto errout;

	}

		if (tcf_block_shared(block)) {

			NL_SET_ERR_MSG(extack, "This filter block is shared. Please use the block index to manipulate the filters");

			err = -EOPNOTSUPP;

			goto errout;

		}

	}



	chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;

	if (chain_index > TC_ACT_EXT_VAL_MASK) {
@@ -1119,19 +1122,10 @@ replay: 
		err = -EINVAL;

		goto errout;

	}

	chain = tcf_chain_get(block, chain_index,

			      n->nlmsg_type == RTM_NEWTFILTER);

	chain = tcf_chain_get(block, chain_index, true);

	if (!chain) {

		NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");

		err = n->nlmsg_type == RTM_NEWTFILTER ? -ENOMEM : -EINVAL;

		goto errout;

	}



	if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {

		tfilter_notify_chain(net, skb, block, q, parent, n,

				     chain, RTM_DELTFILTER);

		tcf_chain_flush(chain);

		err = 0;

		err = -ENOMEM;

		goto errout;

	}
@@ -1152,8 +1146,7 @@ replay: 
			goto errout;

		}



		if (n->nlmsg_type != RTM_NEWTFILTER ||

		    !(n->nlmsg_flags & NLM_F_CREATE)) {

		if (!(n->nlmsg_flags & NLM_F_CREATE)) {

			NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");

			err = -ENOENT;

			goto errout;
@@ -1178,35 +1171,133 @@ replay: 
	fh = tp->ops->get(tp, t->tcm_handle);



	if (!fh) {

		if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {

			tcf_chain_tp_remove(chain, &chain_info, tp);

		if (!(n->nlmsg_flags & NLM_F_CREATE)) {

			NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");

			err = -ENOENT;

			goto errout;

		}

	} else if (n->nlmsg_flags & NLM_F_EXCL) {

		NL_SET_ERR_MSG(extack, "Filter already exists");

		err = -EEXIST;

		goto errout;

	}



	err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,

			      n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE,

			      extack);

	if (err == 0) {

		if (tp_created)

			tcf_chain_tp_insert(chain, &chain_info, tp);

		tfilter_notify(net, skb, n, tp, block, q, parent, fh,

				       RTM_DELTFILTER, false);

			tcf_proto_destroy(tp, extack);

			       RTM_NEWTFILTER, false);

	} else {

		if (tp_created)

			tcf_proto_destroy(tp, NULL);

	}



errout:

	if (chain)

		tcf_chain_put(chain);

	if (err == -EAGAIN)

		/* Replay the request. */

		goto replay;

	return err;

}



static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,

			  struct netlink_ext_ack *extack)

{

	struct net *net = sock_net(skb->sk);

	struct nlattr *tca[TCA_MAX + 1];

	struct tcmsg *t;

	u32 protocol;

	u32 prio;

	u32 parent;

	u32 chain_index;

	struct Qdisc *q = NULL;

	struct tcf_chain_info chain_info;

	struct tcf_chain *chain = NULL;

	struct tcf_block *block;

	struct tcf_proto *tp = NULL;

	unsigned long cl = 0;

	void *fh = NULL;

	int err;



	if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))

		return -EPERM;



	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);

	if (err < 0)

		return err;



	t = nlmsg_data(n);

	protocol = TC_H_MIN(t->tcm_info);

	prio = TC_H_MAJ(t->tcm_info);

	parent = t->tcm_parent;



	if (prio == 0 && (protocol || t->tcm_handle || tca[TCA_KIND])) {

		NL_SET_ERR_MSG(extack, "Cannot flush filters with protocol, handle or kind set");

		return -ENOENT;

	}



	/* Find head of filter chain. */



	block = tcf_block_find(net, &q, &parent, &cl,

			       t->tcm_ifindex, t->tcm_block_index, extack);

	if (IS_ERR(block)) {

		err = PTR_ERR(block);

		goto errout;

	}



	chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;

	if (chain_index > TC_ACT_EXT_VAL_MASK) {

		NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");

		err = -EINVAL;

		goto errout;

	}

	chain = tcf_chain_get(block, chain_index, false);

	if (!chain) {

		NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");

		err = -EINVAL;

		goto errout;

	}



	if (prio == 0) {

		tfilter_notify_chain(net, skb, block, q, parent, n,

				     chain, RTM_DELTFILTER);

		tcf_chain_flush(chain);

		err = 0;

		goto errout;

	}



		if (n->nlmsg_type != RTM_NEWTFILTER ||

		    !(n->nlmsg_flags & NLM_F_CREATE)) {

			NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");

			err = -ENOENT;

	tp = tcf_chain_tp_find(chain, &chain_info, protocol,

			       prio, false);

	if (!tp || IS_ERR(tp)) {

		NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");

		err = PTR_ERR(tp);

		goto errout;

	} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {

		NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");

		err = -EINVAL;

		goto errout;

	}



	fh = tp->ops->get(tp, t->tcm_handle);



	if (!fh) {

		if (t->tcm_handle == 0) {

			tcf_chain_tp_remove(chain, &chain_info, tp);

			tfilter_notify(net, skb, n, tp, block, q, parent, fh,

				       RTM_DELTFILTER, false);

			tcf_proto_destroy(tp, extack);

			err = 0;

		} else {

			NL_SET_ERR_MSG(extack, "Specified filter handle not found");

			err = -ENOENT;

		}

	} else {

		bool last;



		switch (n->nlmsg_type) {

		case RTM_NEWTFILTER:

			if (n->nlmsg_flags & NLM_F_EXCL) {

				if (tp_created)

					tcf_proto_destroy(tp, NULL);

				NL_SET_ERR_MSG(extack, "Filter already exists");

				err = -EEXIST;

				goto errout;

			}

			break;

		case RTM_DELTFILTER:

		err = tfilter_del_notify(net, skb, n, tp, block,

					 q, parent, fh, false, &last,

					 extack);
@@ -1216,39 +1307,96 @@ replay: 
			tcf_chain_tp_remove(chain, &chain_info, tp);

			tcf_proto_destroy(tp, extack);

		}

			goto errout;

		case RTM_GETTFILTER:

			err = tfilter_notify(net, skb, n, tp, block, q, parent,

					     fh, RTM_NEWTFILTER, true);

	}



errout:

	if (chain)

		tcf_chain_put(chain);

	return err;

}



static int tc_get_tfilter(struct sk_buff *skb, struct nlmsghdr *n,

			  struct netlink_ext_ack *extack)

{

	struct net *net = sock_net(skb->sk);

	struct nlattr *tca[TCA_MAX + 1];

	struct tcmsg *t;

	u32 protocol;

	u32 prio;

	u32 parent;

	u32 chain_index;

	struct Qdisc *q = NULL;

	struct tcf_chain_info chain_info;

	struct tcf_chain *chain = NULL;

	struct tcf_block *block;

	struct tcf_proto *tp = NULL;

	unsigned long cl = 0;

	void *fh = NULL;

	int err;



	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);

	if (err < 0)

				NL_SET_ERR_MSG(extack, "Failed to send filter notify message");

		return err;



	t = nlmsg_data(n);

	protocol = TC_H_MIN(t->tcm_info);

	prio = TC_H_MAJ(t->tcm_info);

	parent = t->tcm_parent;



	if (prio == 0) {

		NL_SET_ERR_MSG(extack, "Invalid filter command with priority of zero");

		return -ENOENT;

	}



	/* Find head of filter chain. */



	block = tcf_block_find(net, &q, &parent, &cl,

			       t->tcm_ifindex, t->tcm_block_index, extack);

	if (IS_ERR(block)) {

		err = PTR_ERR(block);

		goto errout;

	}



	chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;

	if (chain_index > TC_ACT_EXT_VAL_MASK) {

		NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");

		err = -EINVAL;

		goto errout;

		default:

			NL_SET_ERR_MSG(extack, "Invalid netlink message type");

	}

	chain = tcf_chain_get(block, chain_index, false);

	if (!chain) {

		NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");

		err = -EINVAL;

		goto errout;

	}



	tp = tcf_chain_tp_find(chain, &chain_info, protocol,

			       prio, false);

	if (!tp || IS_ERR(tp)) {

		NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");

		err = PTR_ERR(tp);

		goto errout;

	} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {

		NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");

		err = -EINVAL;

		goto errout;

	}



	err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,

			      n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE,

			      extack);

	if (err == 0) {

		if (tp_created)

			tcf_chain_tp_insert(chain, &chain_info, tp);

		tfilter_notify(net, skb, n, tp, block, q, parent, fh,

			       RTM_NEWTFILTER, false);

	fh = tp->ops->get(tp, t->tcm_handle);



	if (!fh) {

		NL_SET_ERR_MSG(extack, "Specified filter handle not found");

		err = -ENOENT;

	} else {

		if (tp_created)

			tcf_proto_destroy(tp, NULL);

		err = tfilter_notify(net, skb, n, tp, block, q, parent,

				     fh, RTM_NEWTFILTER, true);

		if (err < 0)

			NL_SET_ERR_MSG(extack, "Failed to send filter notify message");

	}



errout:

	if (chain)

		tcf_chain_put(chain);

	if (err == -EAGAIN)

		/* Replay the request. */

		goto replay;

	return err;

}
@@ -1634,9 +1782,9 @@ static int __init tc_filter_init(void) 
	if (err)

		goto err_register_pernet_subsys;



	rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, 0);

	rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, 0);

	rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,

	rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_new_tfilter, NULL, 0);

	rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_del_tfilter, NULL, 0);

	rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_get_tfilter,

		      tc_dump_tfilter, 0);



	return 0;

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