Re: [GIT] Networking

[Eric Dumazet]

Le dimanche 18 septembre 2011 Ã 12:55 -0700, Linus Torvalds a Ãcrit :
> On Sun, Sep 18, 2011 at 12:48 PM, Markus Trippelsdorf
> <markus@xxxxxxxxxxxxxxx> wrote:
> >
> > The following works for me:
> 
> No it doesn't. It may *compile* for you, but it doesn't work for you.
> It avoids all the other stuff that tcp_syn_flood_action() also does
> (notably the printout).
> 
> The real fix looks to be either:
> 
>  - make an empty (inline/macro) cookie_v4_init_sequence() for the
> non-syncookie config case
> 

Yes, this one seems the less ugly.

Frankly, we should remove CONFIG_SYN_COOKIE option...

Sorry for the mess, dont blame David on this, since netdev guys
probably always use CONFIG_SYN_COOKIE.

Thanks

[PATCH] tcp: fix build error if !CONFIG_SYN_COOKIE

commit 946cedccbd7387 (tcp: Change possible SYN flooding messages)
added a build error if CONFIG_SYN_COOKIE=n

Reported-by: Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
---
 include/net/tcp.h |   19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index e9b48b0..f860d64 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -431,17 +431,34 @@ extern int tcp_disconnect(struct sock *sk, int flags);
 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, 
 				    struct ip_options *opt);
+#ifdef CONFIG_SYN_COOKIE
 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 
 				     __u16 *mss);
+#else
+static inline __u32 cookie_v4_init_sequence(struct sock *sk,
+					    struct sk_buff *skb,
+					    __u16 *mss)
+{
+	return 0;
+}
+#endif
 
 extern __u32 cookie_init_timestamp(struct request_sock *req);
 extern bool cookie_check_timestamp(struct tcp_options_received *opt, bool *);
 
 /* From net/ipv6/syncookies.c */
 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
+#ifdef CONFIG_SYN_COOKIE
 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
 				     __u16 *mss);
-
+#else
+static inline __u32 cookie_v6_init_sequence(struct sock *sk,
+					    struct sk_buff *skb,
+					    __u16 *mss)
+{
+	return 0;
+}
+#endif
 /* tcp_output.c */
 
 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,


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