Subject: Re: [PATCH net-next] tcp: fix build fong CONFIG_MPTCP=n

From: Florian Westphal <[email-masked]>
Date: Sat, 1 Aug 2020 09:46:45 +0200

Eric Dumazet <[email-masked]> wrote:
> Fixes these errors:
> 
> net/ipv4/syncookies.c: In function 'tcp_get_cookie_sock':
> net/ipv4/syncookies.c:216:19: error: 'struct tcp_request_sock' has no
> member named 'drop_req'
>   216 |   if (tcp_rsk(req)->drop_req) {
>       |                   ^~
> net/ipv4/syncookies.c: In function 'cookie_tcp_reqsk_alloc':
> net/ipv4/syncookies.c:289:27: warning: unused variable 'treq'
> [-Wunused-variable]
>   289 |  struct tcp_request_sock *treq;
>       |                           ^~~~

Ugh, sorry about this.

> make[3]: *** [scripts/Makefile.build:280: net/ipv4/syncookies.o] Error 1
> make[3]: *** Waiting for unfinished jobs....
>
> Fixes: 9466a1ccebbe ("mptcp: enable JOIN requests even if cookies are in use")
> Signed-off-by: Eric Dumazet <[email-masked]>
> Cc: Florian Westphal <[email-masked]>
> ---
>  net/ipv4/syncookies.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
> index 11b20474be8310d7070750a1c7b4013f2fba2f55..f0794f0232bae749244fff35d8b96b1f561a5e87 100644
> --- a/net/ipv4/syncookies.c
> +++ b/net/ipv4/syncookies.c
> @@ -213,7 +213,7 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
>  		tcp_sk(child)->tsoffset = tsoff;
>  		sock_rps_save_rxhash(child, skb);
>  
> -		if (tcp_rsk(req)->drop_req) {
> +		if (rsk_drop_req(req)) {

This hunk breaks join self test for mptcp, but it should not. Looks like
cookie path missed a ->is_mptcp = 1 somewhere.  Investigating.