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Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ip_forward.c7
-rw-r--r--net/ipv4/ip_output.c8
-rw-r--r--net/ipv4/route.c3
-rw-r--r--net/ipv4/sysctl_net_ipv4.c7
4 files changed, 17 insertions, 8 deletions
diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c
index 694de3b7aebf..e9f1217a8afd 100644
--- a/net/ipv4/ip_forward.c
+++ b/net/ipv4/ip_forward.c
@@ -54,6 +54,7 @@ static int ip_forward_finish(struct sk_buff *skb)
int ip_forward(struct sk_buff *skb)
{
+ u32 mtu;
struct iphdr *iph; /* Our header */
struct rtable *rt; /* Route we use */
struct ip_options *opt = &(IPCB(skb)->opt);
@@ -88,11 +89,13 @@ int ip_forward(struct sk_buff *skb)
if (opt->is_strictroute && rt->rt_uses_gateway)
goto sr_failed;
- if (unlikely(skb->len > dst_mtu(&rt->dst) && !skb_is_gso(skb) &&
+ IPCB(skb)->flags |= IPSKB_FORWARDED;
+ mtu = ip_dst_mtu_maybe_forward(&rt->dst, true);
+ if (unlikely(skb->len > mtu && !skb_is_gso(skb) &&
(ip_hdr(skb)->frag_off & htons(IP_DF))) && !skb->local_df) {
IP_INC_STATS(dev_net(rt->dst.dev), IPSTATS_MIB_FRAGFAILS);
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
- htonl(dst_mtu(&rt->dst)));
+ htonl(mtu));
goto drop;
}
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index df184616493f..9a78804cfe9c 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -449,6 +449,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
__be16 not_last_frag;
struct rtable *rt = skb_rtable(skb);
int err = 0;
+ bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
dev = rt->dst.dev;
@@ -458,12 +459,13 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
iph = ip_hdr(skb);
+ mtu = ip_dst_mtu_maybe_forward(&rt->dst, forwarding);
if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->local_df) ||
(IPCB(skb)->frag_max_size &&
- IPCB(skb)->frag_max_size > dst_mtu(&rt->dst)))) {
+ IPCB(skb)->frag_max_size > mtu))) {
IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
- htonl(ip_skb_dst_mtu(skb)));
+ htonl(mtu));
kfree_skb(skb);
return -EMSGSIZE;
}
@@ -473,7 +475,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
*/
hlen = iph->ihl * 4;
- mtu = dst_mtu(&rt->dst) - hlen; /* Size of data space */
+ mtu = mtu - hlen; /* Size of data space */
#ifdef CONFIG_BRIDGE_NETFILTER
if (skb->nf_bridge)
mtu -= nf_bridge_mtu_reduction(skb);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index f8da28278014..25071b48921c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -112,9 +112,6 @@
#define RT_FL_TOS(oldflp4) \
((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
-/* IPv4 datagram length is stored into 16bit field (tot_len) */
-#define IP_MAX_MTU 0xFFFF
-
#define RT_GC_TIMEOUT (300*HZ)
static int ip_rt_max_size;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 1d2480ac2bb6..44eba052b43d 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -831,6 +831,13 @@ static struct ctl_table ipv4_net_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec
},
+ {
+ .procname = "ip_forward_use_pmtu",
+ .data = &init_net.ipv4.sysctl_ip_fwd_use_pmtu,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
{ }
};