Re: [PATCH net-next v9 10/10] tcp: make dropreason in tcp_child_process() work

[Kuniyuki Iwashima <kuniyu@amazon.com>]

From: Jason Xing <kerneljasonxing@gmail.com>
Date: Fri, 23 Feb 2024 18:28:51 +0800
> From: Jason Xing <kernelxing@tencent.com>
> 
> It's time to let it work right now. We've already prepared for this:)
> 
> Signed-off-by: Jason Xing <kernelxing@tencent.com>
> Reviewed-by: Eric Dumazet <edumazet@google.com>
> Reviewed-by: David Ahern <dsahern@kernel.org>

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>


> --
> v9
> Link: https://lore.kernel.org/netdev/c5640fc4-16dc-4058-97c6-bd84bae4fda1@kernel.org/
> Link: https://lore.kernel.org/netdev/CANn89iKE2vYz_6sYd=u3HbqdgiU0BWhdMY9-ivs0Rcht+X+Rfg@mail.gmail.com/
> 1. add reviewed-by tag (David)
> 2. add reviewed-by tag (Eric)
> 
> v8
> Link: https://lore.kernel.org/netdev/CANn89i+huvL_Zidru_sNHbjwgM7==-q49+mgJq7vZPRgH6DgKg@mail.gmail.com/
> Link: https://lore.kernel.org/netdev/CANn89iKmaZZSnk5+CCtSH43jeUgRWNQPV4cjc0vpWNT7nHnQQg@mail.gmail.com/
> 1. squash v7 patch [11/11] into the current patch.
> 2. refine the rcv codes. (Eric)
> 
> v7
> Link: https://lore.kernel.org/all/20240219043815.98410-1-kuniyu@amazon.com/
> 1. adjust the related part of code only since patch [04/11] is changed.
> ---
>  net/ipv4/tcp_ipv4.c | 12 +++++++-----
>  net/ipv6/tcp_ipv6.c | 16 ++++++++++------
>  2 files changed, 17 insertions(+), 11 deletions(-)
> 
> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> index c79e25549972..a22ee5838751 100644
> --- a/net/ipv4/tcp_ipv4.c
> +++ b/net/ipv4/tcp_ipv4.c
> @@ -1907,7 +1907,6 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
>  		return 0;
>  	}
>  
> -	reason = SKB_DROP_REASON_NOT_SPECIFIED;
>  	if (tcp_checksum_complete(skb))
>  		goto csum_err;
>  
> @@ -1917,7 +1916,8 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
>  		if (!nsk)
>  			return 0;
>  		if (nsk != sk) {
> -			if (tcp_child_process(sk, nsk, skb)) {
> +			reason = tcp_child_process(sk, nsk, skb);
> +			if (reason) {
>  				rsk = nsk;
>  				goto reset;
>  			}
> @@ -2276,10 +2276,12 @@ int tcp_v4_rcv(struct sk_buff *skb)
>  		if (nsk == sk) {
>  			reqsk_put(req);
>  			tcp_v4_restore_cb(skb);
> -		} else if (tcp_child_process(sk, nsk, skb)) {
> -			tcp_v4_send_reset(nsk, skb);
> -			goto discard_and_relse;
>  		} else {
> +			drop_reason = tcp_child_process(sk, nsk, skb);
> +			if (drop_reason) {
> +				tcp_v4_send_reset(nsk, skb);
> +				goto discard_and_relse;
> +			}
>  			sock_put(sk);
>  			return 0;
>  		}
> diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
> index 4f8464e04b7f..f677f0fa5196 100644
> --- a/net/ipv6/tcp_ipv6.c
> +++ b/net/ipv6/tcp_ipv6.c
> @@ -1623,7 +1623,6 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
>  	if (np->rxopt.all)
>  		opt_skb = skb_clone_and_charge_r(skb, sk);
>  
> -	reason = SKB_DROP_REASON_NOT_SPECIFIED;
>  	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
>  		struct dst_entry *dst;
>  
> @@ -1654,8 +1653,11 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
>  		struct sock *nsk = tcp_v6_cookie_check(sk, skb);
>  
>  		if (nsk != sk) {
> -			if (nsk && tcp_child_process(sk, nsk, skb))
> -				goto reset;
> +			if (nsk) {
> +				reason = tcp_child_process(sk, nsk, skb);
> +				if (reason)
> +					goto reset;
> +			}
>  			if (opt_skb)
>  				__kfree_skb(opt_skb);
>  			return 0;
> @@ -1854,10 +1856,12 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
>  		if (nsk == sk) {
>  			reqsk_put(req);
>  			tcp_v6_restore_cb(skb);
> -		} else if (tcp_child_process(sk, nsk, skb)) {
> -			tcp_v6_send_reset(nsk, skb);
> -			goto discard_and_relse;
>  		} else {
> +			drop_reason = tcp_child_process(sk, nsk, skb);
> +			if (drop_reason) {
> +				tcp_v6_send_reset(nsk, skb);
> +				goto discard_and_relse;
> +			}
>  			sock_put(sk);
>  			return 0;
>  		}
> -- 
> 2.37.3