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

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c
index 217e2b6863225acf4353e7cd6f4869df3ce1da56..beb5094703cb5e7c6d897bd34f0ccf4a4b86c7ce 100644 (file)
--- a/net/netfilter/xt_TCPMSS.c
+++ b/net/netfilter/xt_TCPMSS.c
@@ -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)