[linux-2.6-block.git] / net / core / fib_rules.c

/*
 * net/core/fib_rules.c		Generic Routing Rules
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License as
 *	published by the Free Software Foundation, version 2.
 *
 * Authors:	Thomas Graf <tgraf@suug.ch>
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/fib_rules.h>

int fib_default_rule_add(struct fib_rules_ops *ops,
			 u32 pref, u32 table, u32 flags)
{
	struct fib_rule *r;

	r = kzalloc(ops->rule_size, GFP_KERNEL);
	if (r == NULL)
		return -ENOMEM;

	atomic_set(&r->refcnt, 1);
	r->action = FR_ACT_TO_TBL;
	r->pref = pref;
	r->table = table;
	r->flags = flags;
	r->fr_net = hold_net(ops->fro_net);

	/* The lock is not required here, the list in unreacheable
	 * at the moment this function is called */
	list_add_tail(&r->list, &ops->rules_list);
	return 0;
}
EXPORT_SYMBOL(fib_default_rule_add);

static void notify_rule_change(int event, struct fib_rule *rule,
			       struct fib_rules_ops *ops, struct nlmsghdr *nlh,
			       u32 pid);

static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
{
	struct fib_rules_ops *ops;

	rcu_read_lock();
	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
		if (ops->family == family) {
			if (!try_module_get(ops->owner))
				ops = NULL;
			rcu_read_unlock();
			return ops;
		}
	}
	rcu_read_unlock();

	return NULL;
}

static void rules_ops_put(struct fib_rules_ops *ops)
{
	if (ops)
		module_put(ops->owner);
}

static void flush_route_cache(struct fib_rules_ops *ops)
{
	if (ops->flush_cache)
		ops->flush_cache();
}

int fib_rules_register(struct fib_rules_ops *ops)
{
	int err = -EEXIST;
	struct fib_rules_ops *o;
	struct net *net;

	net = ops->fro_net;

	if (ops->rule_size < sizeof(struct fib_rule))
		return -EINVAL;

	if (ops->match == NULL || ops->configure == NULL ||
	    ops->compare == NULL || ops->fill == NULL ||
	    ops->action == NULL)
		return -EINVAL;

	spin_lock(&net->rules_mod_lock);
	list_for_each_entry(o, &net->rules_ops, list)
		if (ops->family == o->family)
			goto errout;

	hold_net(net);
	list_add_tail_rcu(&ops->list, &net->rules_ops);
	err = 0;
errout:
	spin_unlock(&net->rules_mod_lock);

	return err;
}

EXPORT_SYMBOL_GPL(fib_rules_register);

void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
{
	struct fib_rule *rule, *tmp;

	list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
		list_del_rcu(&rule->list);
		fib_rule_put(rule);
	}
}
EXPORT_SYMBOL_GPL(fib_rules_cleanup_ops);

void fib_rules_unregister(struct fib_rules_ops *ops)
{
	struct net *net = ops->fro_net;

	spin_lock(&net->rules_mod_lock);
	list_del_rcu(&ops->list);
	fib_rules_cleanup_ops(ops);
	spin_unlock(&net->rules_mod_lock);

	synchronize_rcu();
	release_net(net);
}

EXPORT_SYMBOL_GPL(fib_rules_unregister);

static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
			  struct flowi *fl, int flags)
{
	int ret = 0;

	if (rule->ifindex && (rule->ifindex != fl->iif))
		goto out;

	if ((rule->mark ^ fl->mark) & rule->mark_mask)
		goto out;

	ret = ops->match(rule, fl, flags);
out:
	return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
}

int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
		     int flags, struct fib_lookup_arg *arg)
{
	struct fib_rule *rule;
	int err;

	rcu_read_lock();

	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
jumped:
		if (!fib_rule_match(rule, ops, fl, flags))
			continue;

		if (rule->action == FR_ACT_GOTO) {
			struct fib_rule *target;

			target = rcu_dereference(rule->ctarget);
			if (target == NULL) {
				continue;
			} else {
				rule = target;
				goto jumped;
			}
		} else if (rule->action == FR_ACT_NOP)
			continue;
		else
			err = ops->action(rule, fl, flags, arg);

		if (err != -EAGAIN) {
			fib_rule_get(rule);
			arg->rule = rule;
			goto out;
		}
	}

	err = -ESRCH;
out:
	rcu_read_unlock();

	return err;
}

EXPORT_SYMBOL_GPL(fib_rules_lookup);

static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
			    struct fib_rules_ops *ops)
{
	int err = -EINVAL;

	if (frh->src_len)
		if (tb[FRA_SRC] == NULL ||
		    frh->src_len > (ops->addr_size * 8) ||
		    nla_len(tb[FRA_SRC]) != ops->addr_size)
			goto errout;

	if (frh->dst_len)
		if (tb[FRA_DST] == NULL ||
		    frh->dst_len > (ops->addr_size * 8) ||
		    nla_len(tb[FRA_DST]) != ops->addr_size)
			goto errout;

	err = 0;
errout:
	return err;
}

static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
	struct net *net = sock_net(skb->sk);
	struct fib_rule_hdr *frh = nlmsg_data(nlh);
	struct fib_rules_ops *ops = NULL;
	struct fib_rule *rule, *r, *last = NULL;
	struct nlattr *tb[FRA_MAX+1];
	int err = -EINVAL, unresolved = 0;

	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
		goto errout;

	ops = lookup_rules_ops(net, frh->family);
	if (ops == NULL) {
		err = -EAFNOSUPPORT;
		goto errout;
	}

	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
	if (err < 0)
		goto errout;

	err = validate_rulemsg(frh, tb, ops);
	if (err < 0)
		goto errout;

	rule = kzalloc(ops->rule_size, GFP_KERNEL);
	if (rule == NULL) {
		err = -ENOMEM;
		goto errout;
	}
	rule->fr_net = hold_net(net);

	if (tb[FRA_PRIORITY])
		rule->pref = nla_get_u32(tb[FRA_PRIORITY]);

	if (tb[FRA_IFNAME]) {
		struct net_device *dev;

		rule->ifindex = -1;
		nla_strlcpy(rule->ifname, tb[FRA_IFNAME], IFNAMSIZ);
		dev = __dev_get_by_name(net, rule->ifname);
		if (dev)
			rule->ifindex = dev->ifindex;
	}

	if (tb[FRA_FWMARK]) {
		rule->mark = nla_get_u32(tb[FRA_FWMARK]);
		if (rule->mark)
			/* compatibility: if the mark value is non-zero all bits
			 * are compared unless a mask is explicitly specified.
			 */
			rule->mark_mask = 0xFFFFFFFF;
	}

	if (tb[FRA_FWMASK])
		rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);

	rule->action = frh->action;
	rule->flags = frh->flags;
	rule->table = frh_get_table(frh, tb);

	if (!rule->pref && ops->default_pref)
		rule->pref = ops->default_pref(ops);

	err = -EINVAL;
	if (tb[FRA_GOTO]) {
		if (rule->action != FR_ACT_GOTO)
			goto errout_free;

		rule->target = nla_get_u32(tb[FRA_GOTO]);
		/* Backward jumps are prohibited to avoid endless loops */
		if (rule->target <= rule->pref)
			goto errout_free;

		list_for_each_entry(r, &ops->rules_list, list) {
			if (r->pref == rule->target) {
				rule->ctarget = r;
				break;
			}
		}

		if (rule->ctarget == NULL)
			unresolved = 1;
	} else if (rule->action == FR_ACT_GOTO)
		goto errout_free;

	err = ops->configure(rule, skb, nlh, frh, tb);
	if (err < 0)
		goto errout_free;

	list_for_each_entry(r, &ops->rules_list, list) {
		if (r->pref > rule->pref)
			break;
		last = r;
	}

	fib_rule_get(rule);

	if (ops->unresolved_rules) {
		/*
		 * There are unresolved goto rules in the list, check if
		 * any of them are pointing to this new rule.
		 */
		list_for_each_entry(r, &ops->rules_list, list) {
			if (r->action == FR_ACT_GOTO &&
			    r->target == rule->pref) {
				BUG_ON(r->ctarget != NULL);
				rcu_assign_pointer(r->ctarget, rule);
				if (--ops->unresolved_rules == 0)
					break;
			}
		}
	}

	if (rule->action == FR_ACT_GOTO)
		ops->nr_goto_rules++;

	if (unresolved)
		ops->unresolved_rules++;

	if (last)
		list_add_rcu(&rule->list, &last->list);
	else
		list_add_rcu(&rule->list, &ops->rules_list);

	notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid);
	flush_route_cache(ops);
	rules_ops_put(ops);
	return 0;

errout_free:
	release_net(rule->fr_net);
	kfree(rule);
errout:
	rules_ops_put(ops);
	return err;
}

static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
	struct net *net = sock_net(skb->sk);
	struct fib_rule_hdr *frh = nlmsg_data(nlh);
	struct fib_rules_ops *ops = NULL;
	struct fib_rule *rule, *tmp;
	struct nlattr *tb[FRA_MAX+1];
	int err = -EINVAL;

	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
		goto errout;

	ops = lookup_rules_ops(net, frh->family);
	if (ops == NULL) {
		err = -EAFNOSUPPORT;
		goto errout;
	}

	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
	if (err < 0)
		goto errout;

	err = validate_rulemsg(frh, tb, ops);
	if (err < 0)
		goto errout;

	list_for_each_entry(rule, &ops->rules_list, list) {
		if (frh->action && (frh->action != rule->action))
			continue;

		if (frh->table && (frh_get_table(frh, tb) != rule->table))
			continue;

		if (tb[FRA_PRIORITY] &&
		    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
			continue;

		if (tb[FRA_IFNAME] &&
		    nla_strcmp(tb[FRA_IFNAME], rule->ifname))
			continue;

		if (tb[FRA_FWMARK] &&
		    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
			continue;

		if (tb[FRA_FWMASK] &&
		    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
			continue;

		if (!ops->compare(rule, frh, tb))
			continue;

		if (rule->flags & FIB_RULE_PERMANENT) {
			err = -EPERM;
			goto errout;
		}

		list_del_rcu(&rule->list);

		if (rule->action == FR_ACT_GOTO)
			ops->nr_goto_rules--;

		/*
		 * Check if this rule is a target to any of them. If so,
		 * disable them. As this operation is eventually very
		 * expensive, it is only performed if goto rules have
		 * actually been added.
		 */
		if (ops->nr_goto_rules > 0) {
			list_for_each_entry(tmp, &ops->rules_list, list) {
				if (tmp->ctarget == rule) {
					rcu_assign_pointer(tmp->ctarget, NULL);
					ops->unresolved_rules++;
				}
			}
		}

		synchronize_rcu();
		notify_rule_change(RTM_DELRULE, rule, ops, nlh,
				   NETLINK_CB(skb).pid);
		fib_rule_put(rule);
		flush_route_cache(ops);
		rules_ops_put(ops);
		return 0;
	}

	err = -ENOENT;
errout:
	rules_ops_put(ops);
	return err;
}

static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
					 struct fib_rule *rule)
{
	size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
			 + nla_total_size(IFNAMSIZ) /* FRA_IFNAME */
			 + nla_total_size(4) /* FRA_PRIORITY */
			 + nla_total_size(4) /* FRA_TABLE */
			 + nla_total_size(4) /* FRA_FWMARK */
			 + nla_total_size(4); /* FRA_FWMASK */

	if (ops->nlmsg_payload)
		payload += ops->nlmsg_payload(rule);

	return payload;
}

static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
			    u32 pid, u32 seq, int type, int flags,
			    struct fib_rules_ops *ops)
{
	struct nlmsghdr *nlh;
	struct fib_rule_hdr *frh;

	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
	if (nlh == NULL)
		return -EMSGSIZE;

	frh = nlmsg_data(nlh);
	frh->table = rule->table;
	NLA_PUT_U32(skb, FRA_TABLE, rule->table);
	frh->res1 = 0;
	frh->res2 = 0;
	frh->action = rule->action;
	frh->flags = rule->flags;

	if (rule->action == FR_ACT_GOTO && rule->ctarget == NULL)
		frh->flags |= FIB_RULE_UNRESOLVED;

	if (rule->ifname[0]) {
		NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname);

		if (rule->ifindex == -1)
			frh->flags |= FIB_RULE_DEV_DETACHED;
	}

	if (rule->pref)
		NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);

	if (rule->mark)
		NLA_PUT_U32(skb, FRA_FWMARK, rule->mark);

	if (rule->mark_mask || rule->mark)
		NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask);

	if (rule->target)
		NLA_PUT_U32(skb, FRA_GOTO, rule->target);

	if (ops->fill(rule, skb, nlh, frh) < 0)
		goto nla_put_failure;

	return nlmsg_end(skb, nlh);

nla_put_failure:
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
}

static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
		      struct fib_rules_ops *ops)
{
	int idx = 0;
	struct fib_rule *rule;

	list_for_each_entry(rule, &ops->rules_list, list) {
		if (idx < cb->args[1])
			goto skip;

		if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid,
				     cb->nlh->nlmsg_seq, RTM_NEWRULE,
				     NLM_F_MULTI, ops) < 0)
			break;
skip:
		idx++;
	}
	cb->args[1] = idx;
	rules_ops_put(ops);

	return skb->len;
}

static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct net *net = sock_net(skb->sk);
	struct fib_rules_ops *ops;
	int idx = 0, family;

	family = rtnl_msg_family(cb->nlh);
	if (family != AF_UNSPEC) {
		/* Protocol specific dump request */
		ops = lookup_rules_ops(net, family);
		if (ops == NULL)
			return -EAFNOSUPPORT;

		return dump_rules(skb, cb, ops);
	}

	rcu_read_lock();
	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
		if (idx < cb->args[0] || !try_module_get(ops->owner))
			goto skip;

		if (dump_rules(skb, cb, ops) < 0)
			break;

		cb->args[1] = 0;
	skip:
		idx++;
	}
	rcu_read_unlock();
	cb->args[0] = idx;

	return skb->len;
}

static void notify_rule_change(int event, struct fib_rule *rule,
			       struct fib_rules_ops *ops, struct nlmsghdr *nlh,
			       u32 pid)
{
	struct net *net;
	struct sk_buff *skb;
	int err = -ENOBUFS;

	net = ops->fro_net;
	skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
	if (skb == NULL)
		goto errout;

	err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
	if (err < 0) {
		/* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
		WARN_ON(err == -EMSGSIZE);
		kfree_skb(skb);
		goto errout;
	}

	err = rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
errout:
	if (err < 0)
		rtnl_set_sk_err(net, ops->nlgroup, err);
}

static void attach_rules(struct list_head *rules, struct net_device *dev)
{
	struct fib_rule *rule;

	list_for_each_entry(rule, rules, list) {
		if (rule->ifindex == -1 &&
		    strcmp(dev->name, rule->ifname) == 0)
			rule->ifindex = dev->ifindex;
	}
}

static void detach_rules(struct list_head *rules, struct net_device *dev)
{
	struct fib_rule *rule;

	list_for_each_entry(rule, rules, list)
		if (rule->ifindex == dev->ifindex)
			rule->ifindex = -1;
}


static int fib_rules_event(struct notifier_block *this, unsigned long event,
			    void *ptr)
{
	struct net_device *dev = ptr;
	struct net *net = dev_net(dev);
	struct fib_rules_ops *ops;

	ASSERT_RTNL();
	rcu_read_lock();

	switch (event) {
	case NETDEV_REGISTER:
		list_for_each_entry(ops, &net->rules_ops, list)
			attach_rules(&ops->rules_list, dev);
		break;

	case NETDEV_UNREGISTER:
		list_for_each_entry(ops, &net->rules_ops, list)
			detach_rules(&ops->rules_list, dev);
		break;
	}

	rcu_read_unlock();

	return NOTIFY_DONE;
}

static struct notifier_block fib_rules_notifier = {
	.notifier_call = fib_rules_event,
};

static int fib_rules_net_init(struct net *net)
{
	INIT_LIST_HEAD(&net->rules_ops);
	spin_lock_init(&net->rules_mod_lock);
	return 0;
}

static struct pernet_operations fib_rules_net_ops = {
	.init = fib_rules_net_init,
};

static int __init fib_rules_init(void)
{
	int err;
	rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL);
	rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL);
	rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule);

	err = register_netdevice_notifier(&fib_rules_notifier);
	if (err < 0)
		goto fail;

	err = register_pernet_subsys(&fib_rules_net_ops);
	if (err < 0)
		goto fail_unregister;
	return 0;

fail_unregister:
	unregister_netdevice_notifier(&fib_rules_notifier);
fail:
	rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
	rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
	rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
	return err;
}

subsys_initcall(fib_rules_init);
Commit	Line	Data
14c0b97d TG	1	/*
	2	* net/core/fib_rules.c Generic Routing Rules
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License as
	6	* published by the Free Software Foundation, version 2.
	7	*
	8	* Authors: Thomas Graf <tgraf@suug.ch>
	9	*/
	10
14c0b97d TG	11	#include <linux/types.h>
	12	#include <linux/kernel.h>
	13	#include <linux/list.h>
e9dc8653	14	#include <net/net_namespace.h>
881d966b	15	#include <net/sock.h>
14c0b97d TG	16	#include <net/fib_rules.h>
14c0b97d TG	17
2994c638 DL	18	int fib_default_rule_add(struct fib_rules_ops *ops,
	19	u32 pref, u32 table, u32 flags)
	20	{
	21	struct fib_rule *r;
	22
	23	r = kzalloc(ops->rule_size, GFP_KERNEL);
	24	if (r == NULL)
	25	return -ENOMEM;
	26
	27	atomic_set(&r->refcnt, 1);
	28	r->action = FR_ACT_TO_TBL;
	29	r->pref = pref;
	30	r->table = table;
	31	r->flags = flags;
3661a910	32	r->fr_net = hold_net(ops->fro_net);
2994c638 DL	33
	34	/* The lock is not required here, the list in unreacheable
	35	* at the moment this function is called */
	36	list_add_tail(&r->list, &ops->rules_list);
	37	return 0;
	38	}
	39	EXPORT_SYMBOL(fib_default_rule_add);
	40
9e3a5487	41	static void notify_rule_change(int event, struct fib_rule *rule,
c17084d2 TG	42	struct fib_rules_ops ops, struct nlmsghdr nlh,
c17084d2 TG	43	u32 pid);
14c0b97d	44
5fd30ee7	45	static struct fib_rules_ops lookup_rules_ops(struct net net, int family)
14c0b97d TG	46	{
	47	struct fib_rules_ops *ops;
	48
	49	rcu_read_lock();
5fd30ee7	50	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
14c0b97d TG	51	if (ops->family == family) {
	52	if (!try_module_get(ops->owner))
	53	ops = NULL;
	54	rcu_read_unlock();
	55	return ops;
	56	}
	57	}
	58	rcu_read_unlock();
	59
	60	return NULL;
	61	}
	62
	63	static void rules_ops_put(struct fib_rules_ops *ops)
	64	{
	65	if (ops)
	66	module_put(ops->owner);
	67	}
	68
73417f61 TG	69	static void flush_route_cache(struct fib_rules_ops *ops)
	70	{
	71	if (ops->flush_cache)
	72	ops->flush_cache();
	73	}
	74
9e3a5487	75	int fib_rules_register(struct fib_rules_ops *ops)
14c0b97d TG	76	{
	77	int err = -EEXIST;
	78	struct fib_rules_ops *o;
9e3a5487 DL	79	struct net *net;
	80
	81	net = ops->fro_net;
14c0b97d TG	82
	83	if (ops->rule_size < sizeof(struct fib_rule))
	84	return -EINVAL;
	85
	86	if (ops->match == NULL \|\| ops->configure == NULL \|\|
	87	ops->compare == NULL \|\| ops->fill == NULL \|\|
	88	ops->action == NULL)
	89	return -EINVAL;
	90
5fd30ee7 DL	91	spin_lock(&net->rules_mod_lock);
5fd30ee7 DL	92	list_for_each_entry(o, &net->rules_ops, list)
14c0b97d TG	93	if (ops->family == o->family)
	94	goto errout;
	95
5fd30ee7 DL	96	hold_net(net);
5fd30ee7 DL	97	list_add_tail_rcu(&ops->list, &net->rules_ops);
14c0b97d TG	98	err = 0;
14c0b97d TG	99	errout:
5fd30ee7	100	spin_unlock(&net->rules_mod_lock);
14c0b97d TG	101
	102	return err;
	103	}
	104
	105	EXPORT_SYMBOL_GPL(fib_rules_register);
	106
9eb87f3f	107	void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
14c0b97d TG	108	{
	109	struct fib_rule rule, tmp;
	110
76c72d4f	111	list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
14c0b97d TG	112	list_del_rcu(&rule->list);
	113	fib_rule_put(rule);
	114	}
	115	}
9eb87f3f	116	EXPORT_SYMBOL_GPL(fib_rules_cleanup_ops);
14c0b97d	117
9e3a5487	118	void fib_rules_unregister(struct fib_rules_ops *ops)
14c0b97d	119	{
9e3a5487	120	struct net *net = ops->fro_net;
14c0b97d	121
5fd30ee7	122	spin_lock(&net->rules_mod_lock);
72132c1b DL	123	list_del_rcu(&ops->list);
72132c1b DL	124	fib_rules_cleanup_ops(ops);
5fd30ee7	125	spin_unlock(&net->rules_mod_lock);
14c0b97d TG	126
14c0b97d TG	127	synchronize_rcu();
72132c1b	128	release_net(net);
14c0b97d TG	129	}
	130
	131	EXPORT_SYMBOL_GPL(fib_rules_unregister);
	132
3dfbcc41 TG	133	static int fib_rule_match(struct fib_rule rule, struct fib_rules_ops ops,
	134	struct flowi *fl, int flags)
	135	{
	136	int ret = 0;
	137
	138	if (rule->ifindex && (rule->ifindex != fl->iif))
	139	goto out;
	140
	141	if ((rule->mark ^ fl->mark) & rule->mark_mask)
	142	goto out;
	143
	144	ret = ops->match(rule, fl, flags);
	145	out:
	146	return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
	147	}
	148
14c0b97d TG	149	int fib_rules_lookup(struct fib_rules_ops ops, struct flowi fl,
	150	int flags, struct fib_lookup_arg *arg)
	151	{
	152	struct fib_rule *rule;
	153	int err;
	154
	155	rcu_read_lock();
	156
76c72d4f	157	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
0947c9fe	158	jumped:
3dfbcc41	159	if (!fib_rule_match(rule, ops, fl, flags))
14c0b97d TG	160	continue;
14c0b97d TG	161
0947c9fe TG	162	if (rule->action == FR_ACT_GOTO) {
	163	struct fib_rule *target;
	164
	165	target = rcu_dereference(rule->ctarget);
	166	if (target == NULL) {
	167	continue;
	168	} else {
	169	rule = target;
	170	goto jumped;
	171	}
fa0b2d1d TG	172	} else if (rule->action == FR_ACT_NOP)
	173	continue;
	174	else
0947c9fe TG	175	err = ops->action(rule, fl, flags, arg);
0947c9fe TG	176
14c0b97d TG	177	if (err != -EAGAIN) {
	178	fib_rule_get(rule);
	179	arg->rule = rule;
	180	goto out;
	181	}
	182	}
	183
83886b6b	184	err = -ESRCH;
14c0b97d TG	185	out:
	186	rcu_read_unlock();
	187
	188	return err;
	189	}
	190
	191	EXPORT_SYMBOL_GPL(fib_rules_lookup);
	192
e1701c68 TG	193	static int validate_rulemsg(struct fib_rule_hdr frh, struct nlattr *tb,
	194	struct fib_rules_ops *ops)
	195	{
	196	int err = -EINVAL;
	197
	198	if (frh->src_len)
	199	if (tb[FRA_SRC] == NULL \|\|
	200	frh->src_len > (ops->addr_size * 8) \|\|
	201	nla_len(tb[FRA_SRC]) != ops->addr_size)
	202	goto errout;
	203
	204	if (frh->dst_len)
	205	if (tb[FRA_DST] == NULL \|\|
	206	frh->dst_len > (ops->addr_size * 8) \|\|
	207	nla_len(tb[FRA_DST]) != ops->addr_size)
	208	goto errout;
	209
	210	err = 0;
	211	errout:
	212	return err;
	213	}
	214
9d9e6a58	215	static int fib_nl_newrule(struct sk_buff skb, struct nlmsghdr nlh, void *arg)
14c0b97d	216	{
3b1e0a65	217	struct net *net = sock_net(skb->sk);
14c0b97d TG	218	struct fib_rule_hdr *frh = nlmsg_data(nlh);
	219	struct fib_rules_ops *ops = NULL;
	220	struct fib_rule rule, r, *last = NULL;
	221	struct nlattr *tb[FRA_MAX+1];
0947c9fe	222	int err = -EINVAL, unresolved = 0;
14c0b97d TG	223
	224	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
	225	goto errout;
	226
5fd30ee7	227	ops = lookup_rules_ops(net, frh->family);
14c0b97d	228	if (ops == NULL) {
2fe195cf	229	err = -EAFNOSUPPORT;
14c0b97d TG	230	goto errout;
	231	}
	232
	233	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
	234	if (err < 0)
	235	goto errout;
	236
e1701c68 TG	237	err = validate_rulemsg(frh, tb, ops);
	238	if (err < 0)
	239	goto errout;
	240
14c0b97d TG	241	rule = kzalloc(ops->rule_size, GFP_KERNEL);
	242	if (rule == NULL) {
	243	err = -ENOMEM;
	244	goto errout;
	245	}
3661a910	246	rule->fr_net = hold_net(net);
14c0b97d TG	247
	248	if (tb[FRA_PRIORITY])
	249	rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
	250
	251	if (tb[FRA_IFNAME]) {
	252	struct net_device *dev;
	253
	254	rule->ifindex = -1;
5176f91e	255	nla_strlcpy(rule->ifname, tb[FRA_IFNAME], IFNAMSIZ);
881d966b	256	dev = __dev_get_by_name(net, rule->ifname);
14c0b97d TG	257	if (dev)
	258	rule->ifindex = dev->ifindex;
	259	}
	260
b8964ed9 TG	261	if (tb[FRA_FWMARK]) {
	262	rule->mark = nla_get_u32(tb[FRA_FWMARK]);
	263	if (rule->mark)
	264	/* compatibility: if the mark value is non-zero all bits
	265	* are compared unless a mask is explicitly specified.
	266	*/
	267	rule->mark_mask = 0xFFFFFFFF;
	268	}
	269
	270	if (tb[FRA_FWMASK])
	271	rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
	272
14c0b97d TG	273	rule->action = frh->action;
14c0b97d TG	274	rule->flags = frh->flags;
9e762a4a	275	rule->table = frh_get_table(frh, tb);
14c0b97d TG	276
14c0b97d TG	277	if (!rule->pref && ops->default_pref)
868d13ac	278	rule->pref = ops->default_pref(ops);
14c0b97d	279
0947c9fe TG	280	err = -EINVAL;
	281	if (tb[FRA_GOTO]) {
	282	if (rule->action != FR_ACT_GOTO)
	283	goto errout_free;
	284
	285	rule->target = nla_get_u32(tb[FRA_GOTO]);
	286	/* Backward jumps are prohibited to avoid endless loops */
	287	if (rule->target <= rule->pref)
	288	goto errout_free;
	289
76c72d4f	290	list_for_each_entry(r, &ops->rules_list, list) {
0947c9fe TG	291	if (r->pref == rule->target) {
	292	rule->ctarget = r;
	293	break;
	294	}
	295	}
	296
	297	if (rule->ctarget == NULL)
	298	unresolved = 1;
	299	} else if (rule->action == FR_ACT_GOTO)
	300	goto errout_free;
	301
14c0b97d TG	302	err = ops->configure(rule, skb, nlh, frh, tb);
	303	if (err < 0)
	304	goto errout_free;
	305
76c72d4f	306	list_for_each_entry(r, &ops->rules_list, list) {
14c0b97d TG	307	if (r->pref > rule->pref)
	308	break;
	309	last = r;
	310	}
	311
	312	fib_rule_get(rule);
	313
0947c9fe TG	314	if (ops->unresolved_rules) {
	315	/*
	316	* There are unresolved goto rules in the list, check if
	317	* any of them are pointing to this new rule.
	318	*/
76c72d4f	319	list_for_each_entry(r, &ops->rules_list, list) {
0947c9fe TG	320	if (r->action == FR_ACT_GOTO &&
	321	r->target == rule->pref) {
	322	BUG_ON(r->ctarget != NULL);
	323	rcu_assign_pointer(r->ctarget, rule);
	324	if (--ops->unresolved_rules == 0)
	325	break;
	326	}
	327	}
	328	}
	329
	330	if (rule->action == FR_ACT_GOTO)
	331	ops->nr_goto_rules++;
	332
	333	if (unresolved)
	334	ops->unresolved_rules++;
	335
14c0b97d TG	336	if (last)
	337	list_add_rcu(&rule->list, &last->list);
	338	else
76c72d4f	339	list_add_rcu(&rule->list, &ops->rules_list);
14c0b97d	340
9e3a5487	341	notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid);
73417f61	342	flush_route_cache(ops);
14c0b97d TG	343	rules_ops_put(ops);
	344	return 0;
	345
	346	errout_free:
3661a910	347	release_net(rule->fr_net);
14c0b97d TG	348	kfree(rule);
	349	errout:
	350	rules_ops_put(ops);
	351	return err;
	352	}
	353
9d9e6a58	354	static int fib_nl_delrule(struct sk_buff skb, struct nlmsghdr nlh, void *arg)
14c0b97d	355	{
3b1e0a65	356	struct net *net = sock_net(skb->sk);
14c0b97d TG	357	struct fib_rule_hdr *frh = nlmsg_data(nlh);
14c0b97d TG	358	struct fib_rules_ops *ops = NULL;
0947c9fe	359	struct fib_rule rule, tmp;
14c0b97d TG	360	struct nlattr *tb[FRA_MAX+1];
	361	int err = -EINVAL;
	362
	363	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
	364	goto errout;
	365
5fd30ee7	366	ops = lookup_rules_ops(net, frh->family);
14c0b97d	367	if (ops == NULL) {
2fe195cf	368	err = -EAFNOSUPPORT;
14c0b97d TG	369	goto errout;
	370	}
	371
	372	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
	373	if (err < 0)
	374	goto errout;
	375
e1701c68 TG	376	err = validate_rulemsg(frh, tb, ops);
	377	if (err < 0)
	378	goto errout;
	379
76c72d4f	380	list_for_each_entry(rule, &ops->rules_list, list) {
14c0b97d TG	381	if (frh->action && (frh->action != rule->action))
	382	continue;
	383
9e762a4a	384	if (frh->table && (frh_get_table(frh, tb) != rule->table))
14c0b97d TG	385	continue;
	386
	387	if (tb[FRA_PRIORITY] &&
	388	(rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
	389	continue;
	390
	391	if (tb[FRA_IFNAME] &&
	392	nla_strcmp(tb[FRA_IFNAME], rule->ifname))
	393	continue;
	394
b8964ed9 TG	395	if (tb[FRA_FWMARK] &&
	396	(rule->mark != nla_get_u32(tb[FRA_FWMARK])))
	397	continue;
	398
	399	if (tb[FRA_FWMASK] &&
	400	(rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
	401	continue;
	402
14c0b97d TG	403	if (!ops->compare(rule, frh, tb))
	404	continue;
	405
	406	if (rule->flags & FIB_RULE_PERMANENT) {
	407	err = -EPERM;
	408	goto errout;
	409	}
	410
	411	list_del_rcu(&rule->list);
0947c9fe TG	412
	413	if (rule->action == FR_ACT_GOTO)
	414	ops->nr_goto_rules--;
	415
	416	/*
	417	* Check if this rule is a target to any of them. If so,
	418	* disable them. As this operation is eventually very
	419	* expensive, it is only performed if goto rules have
	420	* actually been added.
	421	*/
	422	if (ops->nr_goto_rules > 0) {
76c72d4f	423	list_for_each_entry(tmp, &ops->rules_list, list) {
0947c9fe TG	424	if (tmp->ctarget == rule) {
	425	rcu_assign_pointer(tmp->ctarget, NULL);
	426	ops->unresolved_rules++;
	427	}
	428	}
	429	}
	430
14c0b97d	431	synchronize_rcu();
9e3a5487	432	notify_rule_change(RTM_DELRULE, rule, ops, nlh,
c17084d2	433	NETLINK_CB(skb).pid);
14c0b97d	434	fib_rule_put(rule);
73417f61	435	flush_route_cache(ops);
14c0b97d TG	436	rules_ops_put(ops);
	437	return 0;
	438	}
	439
	440	err = -ENOENT;
	441	errout:
	442	rules_ops_put(ops);
	443	return err;
	444	}
	445
339bf98f TG	446	static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
	447	struct fib_rule *rule)
	448	{
	449	size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
	450	+ nla_total_size(IFNAMSIZ) /* FRA_IFNAME */
	451	+ nla_total_size(4) /* FRA_PRIORITY */
	452	+ nla_total_size(4) /* FRA_TABLE */
	453	+ nla_total_size(4) /* FRA_FWMARK */
	454	+ nla_total_size(4); /* FRA_FWMASK */
	455
	456	if (ops->nlmsg_payload)
	457	payload += ops->nlmsg_payload(rule);
	458
	459	return payload;
	460	}
	461
14c0b97d TG	462	static int fib_nl_fill_rule(struct sk_buff skb, struct fib_rule rule,
	463	u32 pid, u32 seq, int type, int flags,
	464	struct fib_rules_ops *ops)
	465	{
	466	struct nlmsghdr *nlh;
	467	struct fib_rule_hdr *frh;
	468
	469	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
	470	if (nlh == NULL)
26932566	471	return -EMSGSIZE;
14c0b97d TG	472
	473	frh = nlmsg_data(nlh);
	474	frh->table = rule->table;
9e762a4a	475	NLA_PUT_U32(skb, FRA_TABLE, rule->table);
14c0b97d TG	476	frh->res1 = 0;
	477	frh->res2 = 0;
	478	frh->action = rule->action;
	479	frh->flags = rule->flags;
	480
0947c9fe TG	481	if (rule->action == FR_ACT_GOTO && rule->ctarget == NULL)
	482	frh->flags \|= FIB_RULE_UNRESOLVED;
	483
2b443683	484	if (rule->ifname[0]) {
14c0b97d TG	485	NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname);
14c0b97d TG	486
2b443683 TG	487	if (rule->ifindex == -1)
	488	frh->flags \|= FIB_RULE_DEV_DETACHED;
	489	}
	490
14c0b97d TG	491	if (rule->pref)
	492	NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);
	493
b8964ed9 TG	494	if (rule->mark)
	495	NLA_PUT_U32(skb, FRA_FWMARK, rule->mark);
	496
	497	if (rule->mark_mask \|\| rule->mark)
	498	NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask);
	499
0947c9fe TG	500	if (rule->target)
	501	NLA_PUT_U32(skb, FRA_GOTO, rule->target);
	502
14c0b97d TG	503	if (ops->fill(rule, skb, nlh, frh) < 0)
	504	goto nla_put_failure;
	505
	506	return nlmsg_end(skb, nlh);
	507
	508	nla_put_failure:
26932566 PM	509	nlmsg_cancel(skb, nlh);
26932566 PM	510	return -EMSGSIZE;
14c0b97d TG	511	}
14c0b97d TG	512
c454673d TG	513	static int dump_rules(struct sk_buff skb, struct netlink_callback cb,
c454673d TG	514	struct fib_rules_ops *ops)
14c0b97d TG	515	{
	516	int idx = 0;
	517	struct fib_rule *rule;
14c0b97d	518
76c72d4f	519	list_for_each_entry(rule, &ops->rules_list, list) {
c454673d	520	if (idx < cb->args[1])
14c0b97d TG	521	goto skip;
	522
	523	if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid,
	524	cb->nlh->nlmsg_seq, RTM_NEWRULE,
	525	NLM_F_MULTI, ops) < 0)
	526	break;
	527	skip:
	528	idx++;
	529	}
c454673d	530	cb->args[1] = idx;
14c0b97d TG	531	rules_ops_put(ops);
	532
	533	return skb->len;
	534	}
	535
c454673d TG	536	static int fib_nl_dumprule(struct sk_buff skb, struct netlink_callback cb)
c454673d TG	537	{
3b1e0a65	538	struct net *net = sock_net(skb->sk);
c454673d TG	539	struct fib_rules_ops *ops;
	540	int idx = 0, family;
	541
	542	family = rtnl_msg_family(cb->nlh);
	543	if (family != AF_UNSPEC) {
	544	/* Protocol specific dump request */
5fd30ee7	545	ops = lookup_rules_ops(net, family);
c454673d TG	546	if (ops == NULL)
	547	return -EAFNOSUPPORT;
	548
	549	return dump_rules(skb, cb, ops);
	550	}
	551
	552	rcu_read_lock();
5fd30ee7	553	list_for_each_entry_rcu(ops, &net->rules_ops, list) {
c454673d TG	554	if (idx < cb->args[0] \|\| !try_module_get(ops->owner))
	555	goto skip;
	556
	557	if (dump_rules(skb, cb, ops) < 0)
	558	break;
	559
	560	cb->args[1] = 0;
	561	skip:
	562	idx++;
	563	}
	564	rcu_read_unlock();
	565	cb->args[0] = idx;
	566
	567	return skb->len;
	568	}
14c0b97d	569
9e3a5487	570	static void notify_rule_change(int event, struct fib_rule *rule,
c17084d2 TG	571	struct fib_rules_ops ops, struct nlmsghdr nlh,
c17084d2 TG	572	u32 pid)
14c0b97d	573	{
9e3a5487	574	struct net *net;
c17084d2 TG	575	struct sk_buff *skb;
c17084d2 TG	576	int err = -ENOBUFS;
14c0b97d	577
9e3a5487	578	net = ops->fro_net;
339bf98f	579	skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
14c0b97d	580	if (skb == NULL)
c17084d2 TG	581	goto errout;
	582
	583	err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
26932566 PM	584	if (err < 0) {
	585	/* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
	586	WARN_ON(err == -EMSGSIZE);
	587	kfree_skb(skb);
	588	goto errout;
	589	}
9e3a5487	590
5fd30ee7	591	err = rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
c17084d2 TG	592	errout:
c17084d2 TG	593	if (err < 0)
5fd30ee7	594	rtnl_set_sk_err(net, ops->nlgroup, err);
14c0b97d TG	595	}
	596
	597	static void attach_rules(struct list_head rules, struct net_device dev)
	598	{
	599	struct fib_rule *rule;
	600
	601	list_for_each_entry(rule, rules, list) {
	602	if (rule->ifindex == -1 &&
	603	strcmp(dev->name, rule->ifname) == 0)
	604	rule->ifindex = dev->ifindex;
	605	}
	606	}
	607
	608	static void detach_rules(struct list_head rules, struct net_device dev)
	609	{
	610	struct fib_rule *rule;
	611
	612	list_for_each_entry(rule, rules, list)
	613	if (rule->ifindex == dev->ifindex)
	614	rule->ifindex = -1;
	615	}
	616
	617
	618	static int fib_rules_event(struct notifier_block *this, unsigned long event,
	619	void *ptr)
	620	{
	621	struct net_device *dev = ptr;
c346dca1	622	struct net *net = dev_net(dev);
14c0b97d TG	623	struct fib_rules_ops *ops;
	624
	625	ASSERT_RTNL();
	626	rcu_read_lock();
	627
	628	switch (event) {
	629	case NETDEV_REGISTER:
5fd30ee7	630	list_for_each_entry(ops, &net->rules_ops, list)
76c72d4f	631	attach_rules(&ops->rules_list, dev);
14c0b97d TG	632	break;
	633
	634	case NETDEV_UNREGISTER:
5fd30ee7	635	list_for_each_entry(ops, &net->rules_ops, list)
76c72d4f	636	detach_rules(&ops->rules_list, dev);
14c0b97d TG	637	break;
	638	}
	639
	640	rcu_read_unlock();
	641
	642	return NOTIFY_DONE;
	643	}
	644
	645	static struct notifier_block fib_rules_notifier = {
	646	.notifier_call = fib_rules_event,
	647	};
	648
5fd30ee7 DL	649	static int fib_rules_net_init(struct net *net)
	650	{
	651	INIT_LIST_HEAD(&net->rules_ops);
	652	spin_lock_init(&net->rules_mod_lock);
	653	return 0;
	654	}
	655
	656	static struct pernet_operations fib_rules_net_ops = {
	657	.init = fib_rules_net_init,
	658	};
	659
14c0b97d TG	660	static int __init fib_rules_init(void)
14c0b97d TG	661	{
5fd30ee7	662	int err;
9d9e6a58 TG	663	rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL);
9d9e6a58 TG	664	rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL);
c454673d	665	rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule);
9d9e6a58	666
5fd30ee7 DL	667	err = register_netdevice_notifier(&fib_rules_notifier);
	668	if (err < 0)
	669	goto fail;
	670
	671	err = register_pernet_subsys(&fib_rules_net_ops);
	672	if (err < 0)
	673	goto fail_unregister;
	674	return 0;
	675
	676	fail_unregister:
	677	unregister_netdevice_notifier(&fib_rules_notifier);
	678	fail:
	679	rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
	680	rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
	681	rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
	682	return err;
14c0b97d TG	683	}
	684
	685	subsys_initcall(fib_rules_init);