From: Joe Stringer <joestrin...@nicira.com>
From upstream f87c10a8aa1e ("ipv4: introduce ip_dst_mtu_maybe_forward
and protect forwarding path against pmtu spoofing")
Signed-off-by: Joe Stringer <joestrin...@nicira.com>
---
acinclude.m4 | 1 +
datapath/linux/compat/include/net/ip.h | 39 ++++++++++++++++++++++++++++++++++
2 files changed, 40 insertions(+)
diff --git a/acinclude.m4 b/acinclude.m4
index 5aaaa1081262..78da9402b2c0 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -348,6 +348,7 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
OVS_GREP_IFELSE([$KSRC/include/net/ip.h], [inet_get_local_port_range.*net],
[OVS_DEFINE([HAVE_INET_GET_LOCAL_PORT_RANGE_USING_NET])])
OVS_GREP_IFELSE([$KSRC/include/net/ip.h], [ip_is_fragment])
+ OVS_GREP_IFELSE([$KSRC/include/net/ip.h], [ip_skb_dst_mtu])
OVS_GREP_IFELSE([$KSRC/include/net/dst_metadata.h], [metadata_dst])
OVS_GREP_IFELSE([$KSRC/include/linux/net.h], [sock_create_kern.*net],
diff --git a/datapath/linux/compat/include/net/ip.h
b/datapath/linux/compat/include/net/ip.h
index a9401a7f0e7c..ead6e2904ba7 100644
--- a/datapath/linux/compat/include/net/ip.h
+++ b/datapath/linux/compat/include/net/ip.h
@@ -22,4 +22,43 @@ static inline void rpl_inet_get_local_port_range(struct net
*net, int *low,
#endif
+/* IPv4 datagram length is stored into 16bit field (tot_len) */
+#ifndef IP_MAX_MTU
+#define IP_MAX_MTU 0xFFFFU
+#endif
+
+#ifndef HAVE_IP_SKB_DST_MTU
+static inline bool rpl_ip_sk_use_pmtu(const struct sock *sk)
+{
+ return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
+}
+#define ip_sk_use_pmtu rpl_ip_sk_use_pmtu
+
+static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry
*dst,
+ bool forwarding)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,14,0)
+ struct net *net = dev_net(dst->dev);
+
+ if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
+ dst_metric_locked(dst, RTAX_MTU) ||
+ !forwarding)
+ return dst_mtu(dst);
+#endif
+
+ return min(dst->dev->mtu, IP_MAX_MTU);
+}
+
+static inline unsigned int rpl_ip_skb_dst_mtu(const struct sk_buff *skb)
+{
+ if (!skb->sk || ip_sk_use_pmtu(skb->sk)) {
+ bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
+ return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
+ } else {
+ return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);
+ }
+}
+#define ip_skb_dst_mtu rpl_ip_skb_dst_mtu
+#endif /* HAVE_IP_SKB_DST_MTU */
+
#endif
--
2.1.4
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