On Tue, 2017-05-09 at 21:40 +0800, Hangbin Liu wrote:
>
> I saw we checked the dev in this function
>
> dev = skb->dev;
> if (dev) {
> fq->iif = dev->ifindex;
> skb->dev = NULL;
> }
>
> and upper caller ipv6_frag_rcv()
>
> fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
> skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
>
>
> Apologise that I did not do enough research to make sure whether skb->dev
> could be NULL or not. I will do the check recently and reply when got a
> confirmation.
If really having a NULL dev is possible, I would rather change things
this way, as your fix has side effects.
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index
e1da5b888cc4901711d573075f8ae4eada7f086e..6c0a2b74ba705cbe13b4e7522d958a9c3d395c29
100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -77,7 +77,7 @@ static u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
static struct inet_frags ip6_frags;
static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
- struct net_device *dev);
+ struct net_device *dev, struct inet6_dev *idev);
/*
* callers should be careful not to use the hash value outside the ipfrag_lock
@@ -209,6 +209,7 @@ fq_find(struct net *net, __be32 id, const struct in6_addr
*src,
static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
struct frag_hdr *fhdr, int nhoff)
{
+ struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
struct sk_buff *prev, *next;
struct net_device *dev;
int offset, end, fragsize;
@@ -223,8 +224,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct
sk_buff *skb,
((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
if ((unsigned int)end > IPV6_MAXPLEN) {
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_INHDRERRORS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
((u8 *)&fhdr->frag_off -
skb_network_header(skb)));
@@ -258,8 +258,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct
sk_buff *skb,
/* RFC2460 says always send parameter problem in
* this case. -DaveM
*/
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_INHDRERRORS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
offsetof(struct ipv6hdr,
payload_len));
return -1;
@@ -354,7 +353,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct
sk_buff *skb,
unsigned long orefdst = skb->_skb_refdst;
skb->_skb_refdst = 0UL;
- res = ip6_frag_reasm(fq, prev, dev);
+ res = ip6_frag_reasm(fq, prev, dev, idev);
skb->_skb_refdst = orefdst;
return res;
}
@@ -365,8 +364,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct
sk_buff *skb,
discard_fq:
inet_frag_kill(&fq->q, &ip6_frags);
err:
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_REASMFAILS);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMFAILS);
kfree_skb(skb);
return -1;
}
@@ -381,7 +379,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct
sk_buff *skb,
* the last and the first frames arrived and all the bits are here.
*/
static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
- struct net_device *dev)
+ struct net_device *dev, struct inet6_dev *idev)
{
struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
struct sk_buff *fp, *head = fq->q.fragments;
@@ -505,9 +503,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct
sk_buff *prev,
skb_postpush_rcsum(head, skb_network_header(head),
skb_network_header_len(head));
- rcu_read_lock();
- __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
- rcu_read_unlock();
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_REASMOKS);
fq->q.fragments = NULL;
fq->q.fragments_tail = NULL;
return 1;
