netfilter: xt_TPROXY: remove pr_debug invocations

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.

diff from v1 -> v2:
* converted if statement one-liner style
* x == NULL is now !x

Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

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;
 }
 
@@ -122,16 +114,12 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
 	int tproto;
 
 	tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
-	if (tproto < 0) {
+	if (tproto < 0)
-		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) {
+	if (!hp)
-		pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
 		return NF_DROP;
-	}
 
 	/* check if there's an ongoing connection on the packet
 	 * addresses, this happens if the redirect already happened
@@ -168,19 +156,10 @@ 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;
 }