netdev - Re: [PATCH net-next v2] ipv4: tcp: remove per net tcp

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Date:	Sat, 21 Jul 2012 10:28:51 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Hiroaki SHIMODA <shimoda.hiroaki@...il.com>
Cc:	davem@...emloft.net, netdev@...r.kernel.org, therbert@...gle.com,
	wsommerfeld@...gle.com
Subject: Re: [PATCH net-next v2] ipv4: tcp: remove per net tcp_sock


On Sat, 2012-07-21 at 17:00 +0900, Hiroaki SHIMODA wrote:
> On Thu, 19 Jul 2012 19:34:03 +0200
> Eric Dumazet <eric.dumazet@...il.com> wrote:
> 
> > +static DEFINE_PER_CPU(struct inet_sock, unicast_sock) = {
> > +	.sk = {
> > +		.__sk_common = {
> > +			.skc_refcnt = ATOMIC_INIT(1),
> > +		},
> > +		.sk_wmem_alloc	= ATOMIC_INIT(1),
> > +		.sk_allocation	= GFP_ATOMIC,
> > +		.sk_flags	= (1UL << SOCK_USE_WRITE_QUEUE),
> > +	},
> > +	.pmtudisc = IP_PMTUDISC_WANT,
> > +};
> 
> RST packet generated from unicast_sock have 0 TTL value.
> I think ".uc_ttl = -1" is needed in above initialization.

Good catch, thanks a lot !

[PATCH net-next] ipv4: tcp: set unicast_sock uc_ttl to -1

Set unicast_sock uc_ttl to -1 so that we select the right ttl,
instead of sending packets with a 0 ttl.

Bug added in commit be9f4a44e7d4 (ipv4: tcp: remove per net tcp_sock)

Signed-off-by: Hiroaki SHIMODA <shimoda.hiroaki@...il.com>
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/ipv4/ip_output.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index c528f84..665abbb 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1476,7 +1476,8 @@ static DEFINE_PER_CPU(struct inet_sock, unicast_sock) = {
 		.sk_allocation	= GFP_ATOMIC,
 		.sk_flags	= (1UL << SOCK_USE_WRITE_QUEUE),
 	},
-	.pmtudisc = IP_PMTUDISC_WANT,
+	.pmtudisc	= IP_PMTUDISC_WANT,
+	.uc_ttl		= -1,
 };
 
 void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,


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