1 files changed, 108 insertions, 0 deletions

diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h
new file mode 100644
index 000000000000..f87845e2e965
--- /dev/null
+++ b/include/net/inet_ecn.h
@@ -0,0 +1,108 @@
+#ifndef _INET_ECN_H_
+#define _INET_ECN_H_
+
+#include <linux/ip.h>
+#include <net/dsfield.h>
+
+enum {
+        INET_ECN_NOT_ECT = 0,
+        INET_ECN_ECT_1 = 1,
+        INET_ECN_ECT_0 = 2,
+        INET_ECN_CE = 3,
+        INET_ECN_MASK = 3,
+};
+
+static inline int INET_ECN_is_ce(__u8 dsfield)
+{
+        return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
+}
+
+static inline int INET_ECN_is_not_ect(__u8 dsfield)
+{
+        return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
+}
+
+static inline int INET_ECN_is_capable(__u8 dsfield)
+{
+        return (dsfield & INET_ECN_ECT_0);
+}
+
+static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
+{
+        outer &= ~INET_ECN_MASK;
+        outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
+                                          INET_ECN_ECT_0;
+        return outer;
+}
+
+#define INET_ECN_xmit(sk) do { inet_sk(sk)->tos |= INET_ECN_ECT_0; } while (0)
+#define INET_ECN_dontxmit(sk) \
+        do { inet_sk(sk)->tos &= ~INET_ECN_MASK; } while (0)
+
+#define IP6_ECN_flow_init(label) do {           \
+      (label) &= ~htonl(INET_ECN_MASK << 20);   \
+    } while (0)
+
+#define IP6_ECN_flow_xmit(sk, label) do {                               \
+        if (INET_ECN_is_capable(inet_sk(sk)->tos))                      \
+                (label) |= __constant_htons(INET_ECN_ECT_0 << 4);       \
+    } while (0)
+
+static inline void IP_ECN_set_ce(struct iphdr *iph)
+{
+        u32 check = iph->check;
+        u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
+
+        /*
+         * After the last operation we have (in binary):
+         * INET_ECN_NOT_ECT => 01
+         * INET_ECN_ECT_1   => 10
+         * INET_ECN_ECT_0   => 11
+         * INET_ECN_CE      => 00
+         */
+        if (!(ecn & 2))
+                return;
+
+        /*
+         * The following gives us:
+         * INET_ECN_ECT_1 => check += htons(0xFFFD)
+         * INET_ECN_ECT_0 => check += htons(0xFFFE)
+         */
+        check += htons(0xFFFB) + htons(ecn);
+
+        iph->check = check + (check>=0xFFFF);
+        iph->tos |= INET_ECN_CE;
+}
+
+static inline void IP_ECN_clear(struct iphdr *iph)
+{
+        iph->tos &= ~INET_ECN_MASK;
+}
+
+static inline void ipv4_copy_dscp(struct iphdr *outer, struct iphdr *inner)
+{
+        u32 dscp = ipv4_get_dsfield(outer) & ~INET_ECN_MASK;
+        ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
+}
+
+struct ipv6hdr;
+
+static inline void IP6_ECN_set_ce(struct ipv6hdr *iph)
+{
+        if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
+                return;
+        *(u32*)iph |= htonl(INET_ECN_CE << 20);
+}
+
+static inline void IP6_ECN_clear(struct ipv6hdr *iph)
+{
+        *(u32*)iph &= ~htonl(INET_ECN_MASK << 20);
+}
+
+static inline void ipv6_copy_dscp(struct ipv6hdr *outer, struct ipv6hdr *inner)
+{
+        u32 dscp = ipv6_get_dsfield(outer) & ~INET_ECN_MASK;
+        ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
+}
+
+#endif