1 files changed, 76 insertions, 0 deletions

diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h
index 2fa14691869c..aab73757bc4d 100644
--- a/include/net/inet_ecn.h
+++ b/include/net/inet_ecn.h
@@ -15,6 +15,8 @@ enum {
         INET_ECN_MASK = 3,
 };
 
+extern int sysctl_tunnel_ecn_log;
+
 static inline int INET_ECN_is_ce(__u8 dsfield)
 {
         return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
@@ -145,4 +147,78 @@ static inline int INET_ECN_set_ce(struct sk_buff *skb)
         return 0;
 }
 
+/*
+ * RFC 6080 4.2
+ *  To decapsulate the inner header at the tunnel egress, a compliant
+ *  tunnel egress MUST set the outgoing ECN field to the codepoint at the
+ *  intersection of the appropriate arriving inner header (row) and outer
+ *  header (column) in Figure 4
+ *
+ *      +---------+------------------------------------------------+
+ *      |Arriving |            Arriving Outer Header               |
+ *      |   Inner +---------+------------+------------+------------+
+ *      |  Header | Not-ECT | ECT(0)     | ECT(1)     |     CE     |
+ *      +---------+---------+------------+------------+------------+
+ *      | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)|
+ *      |  ECT(0) |  ECT(0) | ECT(0)     | ECT(1)     |     CE     |
+ *      |  ECT(1) |  ECT(1) | ECT(1) (!) | ECT(1)     |     CE     |
+ *      |    CE   |      CE |     CE     |     CE(!!!)|     CE     |
+ *      +---------+---------+------------+------------+------------+
+ *
+ *             Figure 4: New IP in IP Decapsulation Behaviour
+ *
+ *  returns 0 on success
+ *          1 if something is broken and should be logged (!!! above)
+ *          2 if packet should be dropped
+ */
+static inline int INET_ECN_decapsulate(struct sk_buff *skb,
+                                       __u8 outer, __u8 inner)
+{
+        if (INET_ECN_is_not_ect(inner)) {
+                switch (outer & INET_ECN_MASK) {
+                case INET_ECN_NOT_ECT:
+                        return 0;
+                case INET_ECN_ECT_0:
+                case INET_ECN_ECT_1:
+                        return 1;
+                case INET_ECN_CE:
+                        return 2;
+                }
+        }
+
+        if (INET_ECN_is_ce(outer))
+                INET_ECN_set_ce(skb);
+
+        return 0;
+}
+
+static inline int IP_ECN_decapsulate(const struct iphdr *oiph,
+                                     struct sk_buff *skb)
+{
+        __u8 inner;
+
+        if (skb->protocol == htons(ETH_P_IP))
+                inner = ip_hdr(skb)->tos;
+        else if (skb->protocol == htons(ETH_P_IPV6))
+                inner = ipv6_get_dsfield(ipv6_hdr(skb));
+        else
+                return 0;
+
+        return INET_ECN_decapsulate(skb, oiph->tos, inner);
+}
+
+static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h,
+                                      struct sk_buff *skb)
+{
+        __u8 inner;
+
+        if (skb->protocol == htons(ETH_P_IP))
+                inner = ip_hdr(skb)->tos;
+        else if (skb->protocol == htons(ETH_P_IPV6))
+                inner = ipv6_get_dsfield(ipv6_hdr(skb));
+        else
+                return 0;
+
+        return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner);
+}
 #endif