Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>
---
net/netfilter/xt_TCPMSS.c | 46 ++++++++++++-------------------------
1 files changed, 15 insertions(+), 31 deletions(-)
diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c
index 217e2b6..1be63e6 100644
--- 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 == AF_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();
@@ -178,9 +182,10 @@ 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),
- iph->ihl * 4,
- sizeof(*iph) + sizeof(struct tcphdr));
+ ret = tcpmss_mangle_packet(skb, targinfo,
+ tcpmss_reverse_mtu(skb, AF_INET),
+ iph->ihl * 4,
+ sizeof(*iph) + sizeof(struct tcphdr));
if (ret < 0)
return NF_DROP;
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, AF_INET6),
tcphoff,
sizeof(*ipv6h) + sizeof(struct tcphdr));
if (ret < 0)
--
1.5.4.4
--
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