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);
 	}