1 files changed, 44 insertions, 27 deletions

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 04306989d054..8c5707db53c5 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -27,11 +27,23 @@
 /* This maximum ha length copied from the definition of struct neighbour */
 #define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))
 
+enum mpls_payload_type {
+        MPT_UNSPEC, /* IPv4 or IPv6 */
+        MPT_IPV4 = 4,
+        MPT_IPV6 = 6,
+
+        /* Other types not implemented:
+         *  - Pseudo-wire with or without control word (RFC4385)
+         *  - GAL (RFC5586)
+         */
+};
+
 struct mpls_route { /* next hop label forwarding entry */
         struct net_device __rcu *rt_dev;
         struct rcu_head         rt_rcu;
         u32                     rt_label[MAX_NEW_LABELS];
         u8                      rt_protocol; /* routing protocol that set this entry */
+        u8                      rt_payload_type;
         u8                      rt_labels;
         u8                      rt_via_alen;
         u8                      rt_via_table;
@@ -96,16 +108,8 @@ EXPORT_SYMBOL_GPL(mpls_pkt_too_big);
 static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
                         struct mpls_entry_decoded dec)
 {
-        /* RFC4385 and RFC5586 encode other packets in mpls such that
-         * they don't conflict with the ip version number, making
-         * decoding by examining the ip version correct in everything
-         * except for the strangest cases.
-         *
-         * The strange cases if we choose to support them will require
-         * manual configuration.
-         */
-        struct iphdr *hdr4;
-        bool success = true;
+        enum mpls_payload_type payload_type;
+        bool success = false;
 
         /* The IPv4 code below accesses through the IPv4 header
          * checksum, which is 12 bytes into the packet.
@@ -120,23 +124,32 @@ static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
         if (!pskb_may_pull(skb, 12))
                 return false;
 
-        /* Use ip_hdr to find the ip protocol version */
-        hdr4 = ip_hdr(skb);
-        if (hdr4->version == 4) {
+        payload_type = rt->rt_payload_type;
+        if (payload_type == MPT_UNSPEC)
+                payload_type = ip_hdr(skb)->version;
+
+        switch (payload_type) {
+        case MPT_IPV4: {
+                struct iphdr *hdr4 = ip_hdr(skb);
                 skb->protocol = htons(ETH_P_IP);
                 csum_replace2(&hdr4->check,
                               htons(hdr4->ttl << 8),
                               htons(dec.ttl << 8));
                 hdr4->ttl = dec.ttl;
+                success = true;
+                break;
         }
-        else if (hdr4->version == 6) {
+        case MPT_IPV6: {
                 struct ipv6hdr *hdr6 = ipv6_hdr(skb);
                 skb->protocol = htons(ETH_P_IPV6);
                 hdr6->hop_limit = dec.ttl;
+                success = true;
+                break;
         }
-        else
-                /* version 0 and version 1 are used by pseudo wires */
-                success = false;
+        case MPT_UNSPEC:
+                break;
+        }
+
         return success;
 }
 
@@ -255,16 +268,17 @@ static const struct nla_policy rtm_mpls_policy[RTA_MAX+1] = {
 };
 
 struct mpls_route_config {
-        u32             rc_protocol;
-        u32             rc_ifindex;
-        u16             rc_via_table;
-        u16             rc_via_alen;
-        u8              rc_via[MAX_VIA_ALEN];
-        u32             rc_label;
-        u32             rc_output_labels;
-        u32             rc_output_label[MAX_NEW_LABELS];
-        u32             rc_nlflags;
-        struct nl_info  rc_nlinfo;
+        u32                     rc_protocol;
+        u32                     rc_ifindex;
+        u16                     rc_via_table;
+        u16                     rc_via_alen;
+        u8                      rc_via[MAX_VIA_ALEN];
+        u32                     rc_label;
+        u32                     rc_output_labels;
+        u32                     rc_output_label[MAX_NEW_LABELS];
+        u32                     rc_nlflags;
+        enum mpls_payload_type  rc_payload_type;
+        struct nl_info          rc_nlinfo;
 };
 
 static struct mpls_route *mpls_rt_alloc(size_t alen)
@@ -493,6 +507,7 @@ static int mpls_route_add(struct mpls_route_config *cfg)
                 rt->rt_label[i] = cfg->rc_output_label[i];
         rt->rt_protocol = cfg->rc_protocol;
         RCU_INIT_POINTER(rt->rt_dev, dev);
+        rt->rt_payload_type = cfg->rc_payload_type;
         rt->rt_via_table = cfg->rc_via_table;
         memcpy(rt->rt_via, cfg->rc_via, cfg->rc_via_alen);
 
@@ -1047,6 +1062,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
                         goto nort0;
                 RCU_INIT_POINTER(rt0->rt_dev, lo);
                 rt0->rt_protocol = RTPROT_KERNEL;
+                rt0->rt_payload_type = MPT_IPV4;
                 rt0->rt_via_table = NEIGH_LINK_TABLE;
                 memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
         }
@@ -1057,6 +1073,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
                         goto nort2;
                 RCU_INIT_POINTER(rt2->rt_dev, lo);
                 rt2->rt_protocol = RTPROT_KERNEL;
+                rt2->rt_payload_type = MPT_IPV6;
                 rt2->rt_via_table = NEIGH_LINK_TABLE;
                 memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
         }