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Commit 7b204afd authored by Robert Olsson's avatar Robert Olsson Committed by David S. Miller
Browse files

[IPV4]: Use RCU locking in fib_rules. 



Signed-off-by: default avatarRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d8dcffee

net/ipv4/fib_rules.c

+68 −45
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ 
#include <linux/skbuff.h>

#include <linux/netlink.h>

#include <linux/init.h>

#include <linux/list.h>

#include <linux/rcupdate.h>



#include <net/ip.h>

#include <net/protocol.h>
@@ -52,7 +54,7 @@ 


struct fib_rule

{

	struct fib_rule *r_next;

	struct hlist_node hlist;

	atomic_t	r_clntref;

	u32		r_preference;

	unsigned char	r_table;
@@ -75,6 +77,7 @@ struct fib_rule 
#endif

	char		r_ifname[IFNAMSIZ];

	int		r_dead;

	struct		rcu_head rcu;

};



static struct fib_rule default_rule = {
@@ -85,7 +88,6 @@ static struct fib_rule default_rule = { 
};



static struct fib_rule main_rule = {

	.r_next =	&default_rule,

	.r_clntref =	ATOMIC_INIT(2),

	.r_preference =	0x7FFE,

	.r_table =	RT_TABLE_MAIN,
@@ -93,23 +95,24 @@ static struct fib_rule main_rule = { 
};



static struct fib_rule local_rule = {

	.r_next =	&main_rule,

	.r_clntref =	ATOMIC_INIT(2),

	.r_table =	RT_TABLE_LOCAL,

	.r_action =	RTN_UNICAST,

};



static struct fib_rule *fib_rules = &local_rule;

static DEFINE_RWLOCK(fib_rules_lock);

struct hlist_head fib_rules;



/* writer func called from netlink -- rtnl_sem hold*/



int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)

{

	struct rtattr **rta = arg;

	struct rtmsg *rtm = NLMSG_DATA(nlh);

	struct fib_rule *r, **rp;

	struct fib_rule *r;

	struct hlist_node *node;

	int err = -ESRCH;



	for (rp=&fib_rules; (r=*rp) != NULL; rp=&r->r_next) {

	hlist_for_each_entry(r, node, &fib_rules, hlist) {

		if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 4) == 0) &&

		    rtm->rtm_src_len == r->r_src_len &&

		    rtm->rtm_dst_len == r->r_dst_len &&
@@ -126,10 +129,8 @@ int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) 
			if (r == &local_rule)

				break;



			write_lock_bh(&fib_rules_lock);

			*rp = r->r_next;

			hlist_del_rcu(&r->hlist);

			r->r_dead = 1;

			write_unlock_bh(&fib_rules_lock);

			fib_rule_put(r);

			err = 0;

			break;
@@ -150,21 +151,30 @@ static struct fib_table *fib_empty_table(void) 
	return NULL;

}



static inline void fib_rule_put_rcu(struct rcu_head *head)

{

	struct fib_rule *r = container_of(head, struct fib_rule, rcu);

	kfree(r);

}



void fib_rule_put(struct fib_rule *r)

{

	if (atomic_dec_and_test(&r->r_clntref)) {

		if (r->r_dead)

			kfree(r);

			call_rcu(&r->rcu, fib_rule_put_rcu);

		else

			printk("Freeing alive rule %p\n", r);

	}

}



/* writer func called from netlink -- rtnl_sem hold*/



int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)

{

	struct rtattr **rta = arg;

	struct rtmsg *rtm = NLMSG_DATA(nlh);

	struct fib_rule *r, *new_r, **rp;

	struct fib_rule *r, *new_r, *last = NULL;

	struct hlist_node *node = NULL;

	unsigned char table_id;



	if (rtm->rtm_src_len > 32 || rtm->rtm_dst_len > 32 ||
@@ -188,6 +198,7 @@ int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) 
	if (!new_r)

		return -ENOMEM;

	memset(new_r, 0, sizeof(*new_r));



	if (rta[RTA_SRC-1])

		memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4);

	if (rta[RTA_DST-1])
@@ -220,28 +231,28 @@ int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) 
	if (rta[RTA_FLOW-1])

		memcpy(&new_r->r_tclassid, RTA_DATA(rta[RTA_FLOW-1]), 4);

#endif

	r = container_of(fib_rules.first, struct fib_rule, hlist);



	rp = &fib_rules;

	if (!new_r->r_preference) {

		r = fib_rules;

		if (r && (r = r->r_next) != NULL) {

			rp = &fib_rules->r_next;

		if (r && r->hlist.next != NULL) {

			r = container_of(r->hlist.next, struct fib_rule, hlist);

			if (r->r_preference)

				new_r->r_preference = r->r_preference - 1;

		}

	}



	while ( (r = *rp) != NULL ) {

	hlist_for_each_entry(r, node, &fib_rules, hlist) {

		if (r->r_preference > new_r->r_preference)

			break;

		rp = &r->r_next;

		last = r;

	}



	new_r->r_next = r;

	atomic_inc(&new_r->r_clntref);

	write_lock_bh(&fib_rules_lock);

	*rp = new_r;

	write_unlock_bh(&fib_rules_lock);



	if (last)

		hlist_add_after_rcu(&last->hlist, &new_r->hlist);

	else

		hlist_add_before_rcu(&new_r->hlist, &r->hlist);



	return 0;

}
@@ -254,30 +265,30 @@ u32 fib_rules_tclass(struct fib_result *res) 
}

#endif



/* callers should hold rtnl semaphore */



static void fib_rules_detach(struct net_device *dev)

{

	struct hlist_node *node;

	struct fib_rule *r;



	for (r=fib_rules; r; r=r->r_next) {

		if (r->r_ifindex == dev->ifindex) {

			write_lock_bh(&fib_rules_lock);

	hlist_for_each_entry(r, node, &fib_rules, hlist) {

		if (r->r_ifindex == dev->ifindex)

			r->r_ifindex = -1;

			write_unlock_bh(&fib_rules_lock);

		}



	}

}



/* callers should hold rtnl semaphore */



static void fib_rules_attach(struct net_device *dev)

{

	struct hlist_node *node;

	struct fib_rule *r;



	for (r=fib_rules; r; r=r->r_next) {

		if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {

			write_lock_bh(&fib_rules_lock);

	hlist_for_each_entry(r, node, &fib_rules, hlist) {

		if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0)

			r->r_ifindex = dev->ifindex;

			write_unlock_bh(&fib_rules_lock);

		}

	}

}
@@ -286,14 +297,17 @@ int fib_lookup(const struct flowi *flp, struct fib_result *res) 
	int err;

	struct fib_rule *r, *policy;

	struct fib_table *tb;

	struct hlist_node *node;



	u32 daddr = flp->fl4_dst;

	u32 saddr = flp->fl4_src;



FRprintk("Lookup: %u.%u.%u.%u <- %u.%u.%u.%u ",

	NIPQUAD(flp->fl4_dst), NIPQUAD(flp->fl4_src));

	read_lock(&fib_rules_lock);

	for (r = fib_rules; r; r=r->r_next) {



	rcu_read_lock();



	hlist_for_each_entry_rcu(r, node, &fib_rules, hlist) {

		if (((saddr^r->r_src) & r->r_srcmask) ||

		    ((daddr^r->r_dst) & r->r_dstmask) ||

		    (r->r_tos && r->r_tos != flp->fl4_tos) ||
@@ -309,14 +323,14 @@ FRprintk("tb %d r %d ", r->r_table, r->r_action); 
			policy = r;

			break;

		case RTN_UNREACHABLE:

			read_unlock(&fib_rules_lock);

			rcu_read_unlock();

			return -ENETUNREACH;

		default:

		case RTN_BLACKHOLE:

			read_unlock(&fib_rules_lock);

			rcu_read_unlock();

			return -EINVAL;

		case RTN_PROHIBIT:

			read_unlock(&fib_rules_lock);

			rcu_read_unlock();

			return -EACCES;

		}
@@ -327,16 +341,16 @@ FRprintk("tb %d r %d ", r->r_table, r->r_action); 
			res->r = policy;

			if (policy)

				atomic_inc(&policy->r_clntref);

			read_unlock(&fib_rules_lock);

			rcu_read_unlock();

			return 0;

		}

		if (err < 0 && err != -EAGAIN) {

			read_unlock(&fib_rules_lock);

			rcu_read_unlock();

			return err;

		}

	}

FRprintk("FAILURE\n");

	read_unlock(&fib_rules_lock);

	rcu_read_unlock();

	return -ENETUNREACH;

}
@@ -414,20 +428,25 @@ static __inline__ int inet_fill_rule(struct sk_buff *skb, 
	return -1;

}



/* callers should hold rtnl semaphore */



int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)

{

	int idx;

	int idx = 0;

	int s_idx = cb->args[0];

	struct fib_rule *r;

	struct hlist_node *node;



	rcu_read_lock();

	hlist_for_each_entry(r, node, &fib_rules, hlist) {



	read_lock(&fib_rules_lock);

	for (r=fib_rules, idx=0; r; r = r->r_next, idx++) {

		if (idx < s_idx)

			continue;

		if (inet_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)

			break;

		idx++;

	}

	read_unlock(&fib_rules_lock);

	rcu_read_unlock();

	cb->args[0] = idx;



	return skb->len;
@@ -435,5 +454,9 @@ int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb) 


void __init fib_rules_init(void)

{

	INIT_HLIST_HEAD(&fib_rules);

	hlist_add_head(&local_rule.hlist, &fib_rules);

	hlist_add_after(&local_rule.hlist, &main_rule.hlist);

	hlist_add_after(&main_rule.hlist, &default_rule.hlist);

	register_netdevice_notifier(&fib_rules_notifier);

}