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net: ensure correct skb->tstamp in various fragmenters 

Thomas found that some forwarded packets would be stuck
in FQ packet scheduler because their skb->tstamp contained
timestamps far in the future.

We thought we addressed this point in commit 8203e2d844
("net: clear skb->tstamp in forwarding paths") but there
is still an issue when/if a packet needs to be fragmented.

In order to meet EDT requirements, we have to make sure all
fragments get the original skb->tstamp.

Note that this original skb->tstamp should be zero in
forwarding path, but might have a non zero value in
output path if user decided so.

Fixes: fb420d5d91 ("tcp/fq: move back to CLOCK_MONOTONIC")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Thomas Bartschies <Thomas.Bartschies@cvk.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
alistair/sunxi64-5.4-dsi
Eric Dumazet 2019-10-16 18:00:56 -07:00 committed by David S. Miller
parent 63158ac0ba
commit 9669fffc14
4 changed files with 12 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
net/bridge/netfilter/nf_conntrack_bridge.c
View File

@ -33,6 +33,7 @@ static int nf_br_ip_fragment(struct net *net, struct sock *sk,
{
int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
unsigned int hlen, ll_rs, mtu;
ktime_t tstamp = skb->tstamp;
struct ip_frag_state state;
struct iphdr *iph;
int err;
@ -80,6 +81,7 @@ static int nf_br_ip_fragment(struct net *net, struct sock *sk,
if (iter.frag)
ip_fraglist_prepare(skb, &iter);
skb->tstamp = tstamp;
err = output(net, sk, data, skb);
if (err || !iter.frag)
break;
@ -104,6 +106,7 @@ slow_path:
goto blackhole;
}
skb2->tstamp = tstamp;
err = output(net, sk, data, skb2);
if (err)
goto blackhole;

3
net/ipv4/ip_output.c
View File

@ -771,6 +771,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
struct rtable *rt = skb_rtable(skb);
unsigned int mtu, hlen, ll_rs;
struct ip_fraglist_iter iter;
ktime_t tstamp = skb->tstamp;
struct ip_frag_state state;
int err = 0;
@ -846,6 +847,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
ip_fraglist_prepare(skb, &iter);
}
skb->tstamp = tstamp;
err = output(net, sk, skb);
if (!err)
@ -900,6 +902,7 @@ slow_path:
/*
* Put this fragment into the sending queue.
*/
skb2->tstamp = tstamp;
err = output(net, sk, skb2);
if (err)
goto fail;

3
net/ipv6/ip6_output.c
View File

@ -768,6 +768,7 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
inet6_sk(skb->sk) : NULL;
struct ip6_frag_state state;
unsigned int mtu, hlen, nexthdr_offset;
ktime_t tstamp = skb->tstamp;
int hroom, err = 0;
__be32 frag_id;
u8 *prevhdr, nexthdr = 0;
@ -855,6 +856,7 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
if (iter.frag)
ip6_fraglist_prepare(skb, &iter);
skb->tstamp = tstamp;
err = output(net, sk, skb);
if (!err)
IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
@ -913,6 +915,7 @@ slow_path:
/*
* Put this fragment into the sending queue.
*/
frag->tstamp = tstamp;
err = output(net, sk, frag);
if (err)
goto fail;

3
net/ipv6/netfilter.c
View File

@ -119,6 +119,7 @@ int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
struct sk_buff *))
{
int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
ktime_t tstamp = skb->tstamp;
struct ip6_frag_state state;
u8 *prevhdr, nexthdr = 0;
unsigned int mtu, hlen;
@ -183,6 +184,7 @@ int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
if (iter.frag)
ip6_fraglist_prepare(skb, &iter);
skb->tstamp = tstamp;
err = output(net, sk, data, skb);
if (err || !iter.frag)
break;
@ -215,6 +217,7 @@ slow_path:
goto blackhole;
}
skb2->tstamp = tstamp;
err = output(net, sk, data, skb2);
if (err)
goto blackhole;