linux-kernel - Re: [PATCH net-next v1] tcp: Add mark for TIMEWAIT sockets

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Date:   Wed, 9 May 2018 22:45:16 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Jon Maxwell <jmaxwell37@...il.com>, davem@...emloft.net
Cc:     kuznet@....inr.ac.ru, yoshfuji@...ux-ipv6.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        jmaxwell@...hat.com
Subject: Re: [PATCH net-next v1] tcp: Add mark for TIMEWAIT sockets



On 05/09/2018 10:21 PM, Jon Maxwell wrote:

...

>  	if (th->rst)
> @@ -723,11 +724,17 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
>  	arg.tos = ip_hdr(skb)->tos;
>  	arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
>  	local_bh_disable();
> -	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
> +	ctl_sk = *this_cpu_ptr(net->ipv4.tcp_sk);
> +	if (sk && sk->sk_state == TCP_TIME_WAIT)
> +		ctl_sk->sk_mark = inet_twsk(sk)->tw_mark;
> +	else if (sk && sk_fullsock(sk))

I do not believe we could have a non fullsock here ?

A request socket (SYN_RECV state) at this point is not expected. 


So you can factorize :

if (sk)
        ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
			  inet_twsk(sk)->tw_mark : sk->sk_mark;

(same remark for IPv6)


> +		ctl_sk->sk_mark = sk->sk_mark;
> +	ip_send_unicast_reply(ctl_sk,
>  			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
>  			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
>  			      &arg, arg.iov[0].iov_len);