Re: [GIT] Networking

Eric Dumazet
2011-09-18T20:35:38Z

Le dimanche 18 septembre 2011 à 12:55 -0700, Linus Torvalds a écrit :
> On Sun, Sep 18, 2011 at 12:48 PM, Markus Trippelsdorf
> <markus@trippelsdorf.de> 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@trippelsdorf.de>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
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,