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Commit a8c9486b authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipmr: RCU protection for mfc_cache_array 



Use RCU & RTNL protection for mfc_cache_array[]

ipmr_cache_find() is called under rcu_read_lock();

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4c968709

include/linux/mroute.h

+1 −0
Original line number Diff line number Diff line
@@ -213,6 +213,7 @@ struct mfc_cache { 
			unsigned char ttls[MAXVIFS];	/* TTL thresholds		*/

		} res;

	} mfc_un;

	struct rcu_head	rcu;

};



#define MFC_STATIC		1

net/ipv4/ipmr.c

+47 −40
Original line number Diff line number Diff line
@@ -577,11 +577,18 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify, 
	return 0;

}



static inline void ipmr_cache_free(struct mfc_cache *c)

static void ipmr_cache_free_rcu(struct rcu_head *head)

{

	struct mfc_cache *c = container_of(head, struct mfc_cache, rcu);



	kmem_cache_free(mrt_cachep, c);

}



static inline void ipmr_cache_free(struct mfc_cache *c)

{

	call_rcu(&c->rcu, ipmr_cache_free_rcu);

}



/* Destroy an unresolved cache entry, killing queued skbs

   and reporting error to netlink readers.

 */
@@ -781,6 +788,7 @@ static int vif_add(struct net *net, struct mr_table *mrt, 
	return 0;

}



/* called with rcu_read_lock() */

static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt,

					 __be32 origin,

					 __be32 mcastgrp)
@@ -788,7 +796,7 @@ static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt, 
	int line = MFC_HASH(mcastgrp, origin);

	struct mfc_cache *c;



	list_for_each_entry(c, &mrt->mfc_cache_array[line], list) {

	list_for_each_entry_rcu(c, &mrt->mfc_cache_array[line], list) {

		if (c->mfc_origin == origin && c->mfc_mcastgrp == mcastgrp)

			return c;

	}
@@ -801,8 +809,8 @@ static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt, 
static struct mfc_cache *ipmr_cache_alloc(void)

{

	struct mfc_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_KERNEL);

	if (c == NULL)

		return NULL;



	if (c)

		c->mfc_un.res.minvif = MAXVIFS;

	return c;

}
@@ -810,10 +818,11 @@ static struct mfc_cache *ipmr_cache_alloc(void) 
static struct mfc_cache *ipmr_cache_alloc_unres(void)

{

	struct mfc_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_ATOMIC);

	if (c == NULL)

		return NULL;



	if (c) {

		skb_queue_head_init(&c->mfc_un.unres.unresolved);

		c->mfc_un.unres.expires = jiffies + 10*HZ;

	}

	return c;

}
@@ -1040,9 +1049,7 @@ static int ipmr_mfc_delete(struct mr_table *mrt, struct mfcctl *mfc) 
	list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[line], list) {

		if (c->mfc_origin == mfc->mfcc_origin.s_addr &&

		    c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr) {

			write_lock_bh(&mrt_lock);

			list_del(&c->list);

			write_unlock_bh(&mrt_lock);

			list_del_rcu(&c->list);



			ipmr_cache_free(c);

			return 0;
@@ -1095,9 +1102,7 @@ static int ipmr_mfc_add(struct net *net, struct mr_table *mrt, 
	if (!mrtsock)

		c->mfc_flags |= MFC_STATIC;



	write_lock_bh(&mrt_lock);

	list_add(&c->list, &mrt->mfc_cache_array[line]);

	write_unlock_bh(&mrt_lock);

	list_add_rcu(&c->list, &mrt->mfc_cache_array[line]);



	/*

	 *	Check to see if we resolved a queued list. If so we
@@ -1151,10 +1156,7 @@ static void mroute_clean_tables(struct mr_table *mrt) 
		list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[i], list) {

			if (c->mfc_flags & MFC_STATIC)

				continue;

			write_lock_bh(&mrt_lock);

			list_del(&c->list);

			write_unlock_bh(&mrt_lock);



			list_del_rcu(&c->list);

			ipmr_cache_free(c);

		}

	}
@@ -1422,19 +1424,19 @@ int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg) 
		if (copy_from_user(&sr, arg, sizeof(sr)))

			return -EFAULT;



		read_lock(&mrt_lock);

		rcu_read_lock();

		c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr);

		if (c) {

			sr.pktcnt = c->mfc_un.res.pkt;

			sr.bytecnt = c->mfc_un.res.bytes;

			sr.wrong_if = c->mfc_un.res.wrong_if;

			read_unlock(&mrt_lock);

			rcu_read_unlock();



			if (copy_to_user(arg, &sr, sizeof(sr)))

				return -EFAULT;

			return 0;

		}

		read_unlock(&mrt_lock);

		rcu_read_unlock();

		return -EADDRNOTAVAIL;

	default:

		return -ENOIOCTLCMD;
@@ -1764,7 +1766,7 @@ int ip_mr_input(struct sk_buff *skb) 
		    }

	}



	read_lock(&mrt_lock);

	/* already under rcu_read_lock() */

	cache = ipmr_cache_find(mrt, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);



	/*
@@ -1776,13 +1778,12 @@ int ip_mr_input(struct sk_buff *skb) 
		if (local) {

			struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);

			ip_local_deliver(skb);

			if (skb2 == NULL) {

				read_unlock(&mrt_lock);

			if (skb2 == NULL)

				return -ENOBUFS;

			}

			skb = skb2;

		}



		read_lock(&mrt_lock);

		vif = ipmr_find_vif(mrt, skb->dev);

		if (vif >= 0) {

			int err2 = ipmr_cache_unresolved(mrt, vif, skb);
@@ -1795,8 +1796,8 @@ int ip_mr_input(struct sk_buff *skb) 
		return -ENODEV;

	}



	read_lock(&mrt_lock);

	ip_mr_forward(net, mrt, skb, cache, local);



	read_unlock(&mrt_lock);



	if (local)
@@ -1963,7 +1964,7 @@ int ipmr_get_route(struct net *net, 
	if (mrt == NULL)

		return -ENOENT;



	read_lock(&mrt_lock);

	rcu_read_lock();

	cache = ipmr_cache_find(mrt, rt->rt_src, rt->rt_dst);



	if (cache == NULL) {
@@ -1973,18 +1974,21 @@ int ipmr_get_route(struct net *net, 
		int vif;



		if (nowait) {

			read_unlock(&mrt_lock);

			rcu_read_unlock();

			return -EAGAIN;

		}



		dev = skb->dev;

		read_lock(&mrt_lock);

		if (dev == NULL || (vif = ipmr_find_vif(mrt, dev)) < 0) {

			read_unlock(&mrt_lock);

			rcu_read_unlock();

			return -ENODEV;

		}

		skb2 = skb_clone(skb, GFP_ATOMIC);

		if (!skb2) {

			read_unlock(&mrt_lock);

			rcu_read_unlock();

			return -ENOMEM;

		}
@@ -1997,13 +2001,16 @@ int ipmr_get_route(struct net *net, 
		iph->version = 0;

		err = ipmr_cache_unresolved(mrt, vif, skb2);

		read_unlock(&mrt_lock);

		rcu_read_unlock();

		return err;

	}



	read_lock(&mrt_lock);

	if (!nowait && (rtm->rtm_flags & RTM_F_NOTIFY))

		cache->mfc_flags |= MFC_NOTIFY;

	err = __ipmr_fill_mroute(mrt, skb, cache, rtm);

	read_unlock(&mrt_lock);

	rcu_read_unlock();

	return err;

}
@@ -2055,14 +2062,14 @@ static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb) 
	s_h = cb->args[1];

	s_e = cb->args[2];



	read_lock(&mrt_lock);

	rcu_read_lock();

	ipmr_for_each_table(mrt, net) {

		if (t < s_t)

			goto next_table;

		if (t > s_t)

			s_h = 0;

		for (h = s_h; h < MFC_LINES; h++) {

			list_for_each_entry(mfc, &mrt->mfc_cache_array[h], list) {

			list_for_each_entry_rcu(mfc, &mrt->mfc_cache_array[h], list) {

				if (e < s_e)

					goto next_entry;

				if (ipmr_fill_mroute(mrt, skb,
@@ -2080,7 +2087,7 @@ next_table: 
		t++;

	}

done:

	read_unlock(&mrt_lock);

	rcu_read_unlock();



	cb->args[2] = e;

	cb->args[1] = h;
@@ -2213,14 +2220,14 @@ static struct mfc_cache *ipmr_mfc_seq_idx(struct net *net, 
	struct mr_table *mrt = it->mrt;

	struct mfc_cache *mfc;



	read_lock(&mrt_lock);

	rcu_read_lock();

	for (it->ct = 0; it->ct < MFC_LINES; it->ct++) {

		it->cache = &mrt->mfc_cache_array[it->ct];

		list_for_each_entry(mfc, it->cache, list)

		list_for_each_entry_rcu(mfc, it->cache, list)

			if (pos-- == 0)

				return mfc;

	}

	read_unlock(&mrt_lock);

	rcu_read_unlock();



	spin_lock_bh(&mfc_unres_lock);

	it->cache = &mrt->mfc_unres_queue;
@@ -2279,7 +2286,7 @@ static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos) 
	}



	/* exhausted cache_array, show unresolved */

	read_unlock(&mrt_lock);

	rcu_read_unlock();

	it->cache = &mrt->mfc_unres_queue;

	it->ct = 0;
@@ -2302,7 +2309,7 @@ static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v) 
	if (it->cache == &mrt->mfc_unres_queue)

		spin_unlock_bh(&mfc_unres_lock);

	else if (it->cache == &mrt->mfc_cache_array[it->ct])

		read_unlock(&mrt_lock);

		rcu_read_unlock();

}



static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)