netfilter: xt_TCPMSS: Refactor the codes to decrease one condition check and more readable

The origin codes perform two condition checks with dst_mtu(skb_dst(skb))
and in_mtu. And the last statement is "min(dst_mtu(skb_dst(skb)),
in_mtu) - minlen". It may let reader think about how about the result.
Would it be negative.

Now assign the result of min(dst_mtu(skb_dst(skb)), in_mtu) to a new
variable, then only perform one condition check, and it is more readable.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Gao Feng 2016-09-07 10:40:24 +08:00 committed by Pablo Neira Ayuso
parent 4004d5c374
commit 50f4c7b73f

View File

@ -110,18 +110,14 @@ tcpmss_mangle_packet(struct sk_buff *skb,
if (info->mss == XT_TCPMSS_CLAMP_PMTU) { if (info->mss == XT_TCPMSS_CLAMP_PMTU) {
struct net *net = par->net; struct net *net = par->net;
unsigned int in_mtu = tcpmss_reverse_mtu(net, skb, family); unsigned int in_mtu = tcpmss_reverse_mtu(net, skb, family);
unsigned int min_mtu = min(dst_mtu(skb_dst(skb)), in_mtu);
if (dst_mtu(skb_dst(skb)) <= minlen) { if (min_mtu <= minlen) {
net_err_ratelimited("unknown or invalid path-MTU (%u)\n", net_err_ratelimited("unknown or invalid path-MTU (%u)\n",
dst_mtu(skb_dst(skb))); min_mtu);
return -1; return -1;
} }
if (in_mtu <= minlen) { newmss = min_mtu - minlen;
net_err_ratelimited("unknown or invalid path-MTU (%u)\n",
in_mtu);
return -1;
}
newmss = min(dst_mtu(skb_dst(skb)), in_mtu) - minlen;
} else } else
newmss = info->mss; newmss = info->mss;