netdev - Re: [PATCH] netfilter: xt_TPROXY: remove pr

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Date:   Tue, 12 Jul 2022 11:56:02 -0700
From:   Nathan Chancellor <nathan@...nel.org>
To:     Justin Stitt <justinstitt@...gle.com>
Cc:     pablo@...filter.org, coreteam@...filter.org, davem@...emloft.net,
        edumazet@...gle.com, fw@...len.de, kadlec@...filter.org,
        kuba@...nel.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, ndesaulniers@...gle.com,
        netdev@...r.kernel.org, netfilter-devel@...r.kernel.org,
        pabeni@...hat.com, trix@...hat.com
Subject: Re: [PATCH] netfilter: xt_TPROXY: remove pr_debug invocations

Hi Justin,

On Tue, Jul 12, 2022 at 11:34:52AM -0700, Justin Stitt wrote:
> pr_debug calls are no longer needed in this file.
> 
> Pablo suggested "a patch to remove these pr_debug calls". This patch has
> some other beneficial collateral as it also silences multiple Clang
> -Wformat warnings that were present in the pr_debug calls.
> 
> Suggested-by: Pablo Neira Ayuso <pablo@...filter.org>
> Signed-off-by: Justin Stitt <justinstitt@...gle.com>

Thanks for the patch!

Reviewed-by: Nathan Chancellor <nathan@...nel.org>

Couple of style comments below that probably warrant a v2, you can carry
the above tag forward for future revisions. No need to give me a
"Suggested-by".

> ---
> Suggestion here: https://lore.kernel.org/all/Ys0zZACWwGilTwHx@salvia/
> 
>  net/netfilter/xt_TPROXY.c | 19 -------------------
>  1 file changed, 19 deletions(-)
> 
> diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
> index 459d0696c91a..dc7284e6357b 100644
> --- a/net/netfilter/xt_TPROXY.c
> +++ b/net/netfilter/xt_TPROXY.c
> @@ -74,18 +74,10 @@ tproxy_tg4(struct net *net, struct sk_buff *skb, __be32 laddr, __be16 lport,
>  		/* This should be in a separate target, but we don't do multiple
>  		   targets on the same rule yet */
>  		skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
> -
> -		pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
> -			 iph->protocol, &iph->daddr, ntohs(hp->dest),
> -			 &laddr, ntohs(lport), skb->mark);
> -
>  		nf_tproxy_assign_sock(skb, sk);
>  		return NF_ACCEPT;
>  	}
>  
> -	pr_debug("no socket, dropping: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
> -		 iph->protocol, &iph->saddr, ntohs(hp->source),
> -		 &iph->daddr, ntohs(hp->dest), skb->mark);
>  	return NF_DROP;
>  }
>  
> @@ -123,13 +115,11 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
>  
>  	tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
>  	if (tproto < 0) {

checkpatch.pl should have warned that these if statement braces here and
below are no longer necessary because there is only one statement within
them now.

	if (tproto < 0)
		return NF_DROP;

I believe it is important to do these types of style cleanups when doing
a larger change so that people do not try to do them as standalone
changes, which can irritate maintainers.

> -		pr_debug("unable to find transport header in IPv6 packet, dropping\n");
>  		return NF_DROP;
>  	}
>  
>  	hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
>  	if (hp == NULL) {
> -		pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
>  		return NF_DROP;
>  	}

	if (hp == NULL)
		return NF_DROP;

could even go a step farther and make it

	if (!hp)
		return NF_DROP;

if there is a warning about that.

>  
> @@ -168,19 +158,10 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
>  		/* This should be in a separate target, but we don't do multiple
>  		   targets on the same rule yet */
>  		skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
> -
> -		pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
> -			 tproto, &iph->saddr, ntohs(hp->source),
> -			 laddr, ntohs(lport), skb->mark);
> -
>  		nf_tproxy_assign_sock(skb, sk);
>  		return NF_ACCEPT;
>  	}
>  
> -	pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
> -		 tproto, &iph->saddr, ntohs(hp->source),
> -		 &iph->daddr, ntohs(hp->dest), skb->mark);
> -
>  	return NF_DROP;
>  }
>  
> -- 
> 2.37.0.144.g8ac04bfd2-goog
>