Commit db1a75bd authored by Jan Engelhardt's avatar Jan Engelhardt Committed by David S. Miller
Browse files

netfilter: xt_TCPMSS: collapse tcpmss_reverse_mtu{4,6} into one function 



Signed-off-by: default avatarJan Engelhardt <jengelh@medozas.de>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 72961ecf

net/netfilter/xt_TCPMSS.c

+13 −29
Original line number Diff line number Diff line
@@ -147,17 +147,21 @@ tcpmss_mangle_packet(struct sk_buff *skb, 
	return TCPOLEN_MSS;

}



static u_int32_t tcpmss_reverse_mtu4(const struct iphdr *iph)

static u_int32_t tcpmss_reverse_mtu(const struct sk_buff *skb,

				    unsigned int family)

{

	struct flowi fl = {

		.fl4_dst = iph->saddr,

	};

	struct flowi fl = {};

	const struct nf_afinfo *ai;

	struct rtable *rt = NULL;

	u_int32_t mtu     = ~0U;



	if (family == PF_INET)

		fl.fl4_dst = ip_hdr(skb)->saddr;

	else

		fl.fl6_dst = ipv6_hdr(skb)->saddr;



	rcu_read_lock();

	ai = nf_get_afinfo(AF_INET);

	ai = nf_get_afinfo(family);

	if (ai != NULL)

		ai->route((struct dst_entry **)&rt, &fl);

	rcu_read_unlock();
@@ -178,7 +182,8 @@ tcpmss_tg4(struct sk_buff *skb, const struct net_device *in, 
	__be16 newlen;

	int ret;



	ret = tcpmss_mangle_packet(skb, targinfo, tcpmss_reverse_mtu4(iph),

	ret = tcpmss_mangle_packet(skb, targinfo,

				   tcpmss_reverse_mtu(skb, PF_INET),

				   iph->ihl * 4,

				   sizeof(*iph) + sizeof(struct tcphdr));

	if (ret < 0)
@@ -193,28 +198,6 @@ tcpmss_tg4(struct sk_buff *skb, const struct net_device *in, 
}



#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)

static u_int32_t tcpmss_reverse_mtu6(const struct ipv6hdr *iph)

{

	struct flowi fl = {

		.fl6_dst = iph->saddr,

	};

	const struct nf_afinfo *ai;

	struct rtable *rt = NULL;

	u_int32_t mtu     = ~0U;



	rcu_read_lock();

	ai = nf_get_afinfo(AF_INET6);

	if (ai != NULL)

		ai->route((struct dst_entry **)&rt, &fl);

	rcu_read_unlock();



	if (rt != NULL) {

		mtu = dst_mtu(&rt->u.dst);

		dst_release(&rt->u.dst);

	}

	return mtu;

}



static unsigned int

tcpmss_tg6(struct sk_buff *skb, const struct net_device *in,

           const struct net_device *out, unsigned int hooknum,
@@ -229,7 +212,8 @@ tcpmss_tg6(struct sk_buff *skb, const struct net_device *in, 
	tcphoff = ipv6_skip_exthdr(skb, sizeof(*ipv6h), &nexthdr);

	if (tcphoff < 0)

		return NF_DROP;

	ret = tcpmss_mangle_packet(skb, targinfo, tcpmss_reverse_mtu6(ipv6h),

	ret = tcpmss_mangle_packet(skb, targinfo,

				   tcpmss_reverse_mtu(skb, PF_INET6),

				   tcphoff,

				   sizeof(*ipv6h) + sizeof(struct tcphdr));

	if (ret < 0)