Re: [PATCH 1/3] netfilter: xt_ipvs (netfilter matcher for IPVS)

From: Patrick McHardy
Date: Wed Sep 02 2009 - 10:54:23 EST


Hannes Eder wrote:
> This implements the kernel-space side of the netfilter matcher
> xt_ipvs.

Looks mostly fine to me, just one question:

> +bool ipvs_mt(const struct sk_buff *skb, const struct xt_match_param *par)
> +{
> + const struct xt_ipvs *data = par->matchinfo;
> + const u_int8_t family = par->family;
> + struct ip_vs_iphdr iph;
> + struct ip_vs_protocol *pp;
> + struct ip_vs_conn *cp;
> + int af;
> + bool match = true;
> +
> + if (data->bitmask == XT_IPVS_IPVS_PROPERTY) {
> + match = skb->ipvs_property ^
> + !!(data->invert & XT_IPVS_IPVS_PROPERTY);
> + goto out;
> + }
> +
> + /* other flags than XT_IPVS_IPVS_PROPERTY are set */
> + if (!skb->ipvs_property) {
> + match = false;
> + goto out;
> + }
> +
> + switch (skb->protocol) {
> + case htons(ETH_P_IP):
> + af = AF_INET;
> + break;
> +#ifdef CONFIG_IP_VS_IPV6
> + case htons(ETH_P_IPV6):
> + af = AF_INET6;
> + break;
> +#endif
> + default:
> + match = false;
> + goto out;
> + }

In the NF_INET_LOCAL_OUT hook skb->protocol is invalid. So if you
don't need this, it would make sense to restrict the match to the
other hooks.

Even easier would be to use par->family, which contains the address
family and doesn't need any translation.
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