[PATCH] net: tcp: move sk_rx_dst_set call after tcp_create_openreq_child()

[PATCH] net: tcp: move sk_rx_dst_set call after tcp_create_openreq_child()

[Neal Cardwell]

This commit removes the sk_rx_dst_set calls from
tcp_create_openreq_child(), because at that point the icsk_af_ops
field of ipv6_mapped TCP sockets has not been set to its proper final
value.

Instead, to make sure we get the right sk_rx_dst_set variant
appropriate for the address family of the new connection, we have
tcp_v{4,6}_syn_recv_sock() directly call the appropriate function
shortly after the call to tcp_create_openreq_child() returns.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reported-by: Artem Savkov <artem.savkov@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/tcp_ipv4.c      |    1 +
 net/ipv4/tcp_minisocks.c |    2 --
 net/ipv6/tcp_ipv6.c      |    3 +++
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 7678237..5bf2040 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1462,6 +1462,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 		goto exit_nonewsk;
 
 	newsk->sk_gso_type = SKB_GSO_TCPV4;
+	inet_sk_rx_dst_set(newsk, skb);
 
 	newtp		      = tcp_sk(newsk);
 	newinet		      = inet_sk(newsk);
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index d9c9dce..6ff7f10 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -387,8 +387,6 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
 		struct tcp_sock *oldtp = tcp_sk(sk);
 		struct tcp_cookie_values *oldcvp = oldtp->cookie_values;
 
-		newicsk->icsk_af_ops->sk_rx_dst_set(newsk, skb);
-
 		/* TCP Cookie Transactions require space for the cookie pair,
 		 * as it differs for each connection.  There is no need to
 		 * copy any s_data_payload stored at the original socket.
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index bb9ce2b..492c2d9 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -81,6 +81,8 @@ static void	__tcp_v6_send_check(struct sk_buff *skb,
 				    const struct in6_addr *saddr,
 				    const struct in6_addr *daddr);
 
+static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb);
+
 static const struct inet_connection_sock_af_ops ipv6_mapped;
 static const struct inet_connection_sock_af_ops ipv6_specific;
 #ifdef CONFIG_TCP_MD5SIG
@@ -1270,6 +1272,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 
 	newsk->sk_gso_type = SKB_GSO_TCPV6;
 	__ip6_dst_store(newsk, dst, NULL, NULL);
+	inet6_sk_rx_dst_set(newsk, skb);
 
 	newtcp6sk = (struct tcp6_sock *)newsk;
 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
-- 
1.7.7.3

Re: [PATCH] net: tcp: move sk_rx_dst_set call after tcp_create_openreq_child()

[Eric Dumazet]

On Sat, 2012-08-18 at 23:56 -0400, Neal Cardwell wrote:
> This commit removes the sk_rx_dst_set calls from
> tcp_create_openreq_child(), because at that point the icsk_af_ops
> field of ipv6_mapped TCP sockets has not been set to its proper final
> value.
> 
> Instead, to make sure we get the right sk_rx_dst_set variant
> appropriate for the address family of the new connection, we have
> tcp_v{4,6}_syn_recv_sock() directly call the appropriate function
> shortly after the call to tcp_create_openreq_child() returns.
> 
> Signed-off-by: Neal Cardwell <ncardwell@google.com>
> Reported-by: Artem Savkov <artem.savkov@gmail.com>
> Cc: Eric Dumazet <edumazet@google.com>
> ---


>  		 * copy any s_data_payload stored at the original socket.
> diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
> index bb9ce2b..492c2d9 100644
> --- a/net/ipv6/tcp_ipv6.c
> +++ b/net/ipv6/tcp_ipv6.c
> @@ -81,6 +81,8 @@ static void	__tcp_v6_send_check(struct sk_buff *skb,
>  				    const struct in6_addr *saddr,
>  				    const struct in6_addr *daddr);
>  
> +static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb);
> +


Hi Neal, thanks for taking care of this.

Could you move inet6_sk_rx_dst_set() definition to avoid this forward ?