[PATCH v3 15/30] ipv6: frags: rewrite ip6_expire_frag_queue()

Stephen Hemminger
2018-09-13T20:09:22Z

From: Eric Dumazet <edumazet@google.com>

Make it similar to IPv4 ip_expire(), and release the lock
before calling icmp functions.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 05c0b86b9696802fd0ce5676a92a63f1b455bdf3)
---
net/ipv6/reassembly.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 905a8aee2671..2127da130dc2 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -92,7 +92,9 @@ EXPORT_SYMBOL(ip6_frag_init);
void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq)
{
struct net_device *dev = NULL;
+ struct sk_buff *head;

+ rcu_read_lock();
spin_lock(&fq->q.lock);

if (fq->q.flags & INET_FRAG_COMPLETE)
@@ -100,28 +102,34 @@ void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq)

inet_frag_kill(&fq->q);

- rcu_read_lock();
dev = dev_get_by_index_rcu(net, fq->iif);
if (!dev)
- goto out_rcu_unlock;
+ goto out;

__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);

/* Don't send error if the first segment did not arrive. */
- if (!(fq->q.flags & INET_FRAG_FIRST_IN) || !fq->q.fragments)
- goto out_rcu_unlock;
+ head = fq->q.fragments;
+ if (!(fq->q.flags & INET_FRAG_FIRST_IN) || !head)
+ goto out;

/* But use as source device on which LAST ARRIVED
* segment was received. And do not use fq->dev
* pointer directly, device might already disappeared.
*/
- fq->q.fragments->dev = dev;
- icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
-out_rcu_unlock:
- rcu_read_unlock();
+ head->dev = dev;
+ skb_get(head);
+ spin_unlock(&fq->q.lock);
+
+ icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
+ kfree_skb(head);
+ goto out_rcu_unlock;
+
out:
spin_unlock(&fq->q.lock);
+out_rcu_unlock:
+ rcu_read_unlock();
inet_frag_put(&fq->q);
}
EXPORT_SYMBOL(ip6_expire_frag_queue);
--
2.18.0