mpls: VPLS support

[work-in-progress, works but needs changes]
[v2: refactored lots of things, e.g. dst_metadata, no more genetlink]
[v4: removed pointless include/net/vpls.h, squashed pseudowire control
word support, squashed netlink lwtunnel access bits]

Signed-off-by: David Lamparter <equinox@diac24.net>

Author: eqvinox

include/net/dst_metadata.h

@@ -8,19 +8,25 @@
 enum metadata_type {
 	METADATA_IP_TUNNEL,
 	METADATA_HW_PORT_MUX,
+	METADATA_VPLS,
 };
 
 struct hw_port_info {
 	struct net_device *lower_dev;
 	u32 port_id;
 };
 
+struct vpls_info {
+	u32 pw_label;
+};
+
 struct metadata_dst {
 	struct dst_entry		dst;
 	enum metadata_type		type;
 	union {
 		struct ip_tunnel_info	tun_info;
 		struct hw_port_info	port_info;
+		struct vpls_info	vpls_info;
 	} u;
 };
 
@@ -54,6 +60,15 @@ static inline struct ip_tunnel_info *skb_tunnel_info(struct sk_buff *skb)
 	return NULL;
 }
 
+static inline struct vpls_info *skb_vpls_info(struct sk_buff *skb)
+{
+	struct metadata_dst *md_dst = skb_metadata_dst(skb);
+	if (md_dst && md_dst->type == METADATA_VPLS)
+		return &md_dst->u.vpls_info;
+	return NULL;
+}
+
+
 static inline bool skb_valid_dst(const struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
@@ -74,6 +89,9 @@ static inline int metadata_dst_cmp(const struct metadata_dst *a,
 	case METADATA_HW_PORT_MUX:
 		return memcmp(&a->u.port_info, &b->u.port_info,
 			      sizeof(a->u.port_info));
+	case METADATA_VPLS:
+		return memcmp(&a->u.vpls_info, &b->u.vpls_info,
+			      sizeof(a->u.vpls_info));
 	case METADATA_IP_TUNNEL:
 		return memcmp(&a->u.tun_info, &b->u.tun_info,
 			      sizeof(a->u.tun_info) +
@@ -220,4 +238,10 @@ static inline struct metadata_dst *ipv6_tun_rx_dst(struct sk_buff *skb,
 				  0, ip6_flowlabel(ip6h), flags, tunnel_id,
 				  md_size);
 }
+
+static inline struct metadata_dst *vpls_rx_dst(void)
+{
+	return metadata_dst_alloc(0, METADATA_VPLS, GFP_ATOMIC);
+}
+
 #endif /* __NET_DST_METADATA_H */

include/uapi/linux/lwtunnel.h

@@ -12,6 +12,7 @@ enum lwtunnel_encap_types {
 	LWTUNNEL_ENCAP_SEG6,
 	LWTUNNEL_ENCAP_BPF,
 	LWTUNNEL_ENCAP_SEG6_LOCAL,
+	LWTUNNEL_ENCAP_PSEUDOWIRE,
 	__LWTUNNEL_ENCAP_MAX,
 };
 
@@ -67,4 +68,11 @@ enum {
 
 #define LWT_BPF_MAX_HEADROOM 256
 
+enum {
+	LWT_PSEUDOWIRE_LOCAL_LABEL,
+	__LWT_PSEUDOWIRE_MAX,
+};
+
+#define LWT_PSEUDOWIRE_MAX (__LWT_PSEUDOWIRE_MAX - 1)
+
 #endif /* _UAPI_LWTUNNEL_H_ */

net/core/lwtunnel.c

@@ -49,6 +49,7 @@ static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type)
 	case LWTUNNEL_ENCAP_IP6:
 	case LWTUNNEL_ENCAP_IP:
 	case LWTUNNEL_ENCAP_NONE:
+	case LWTUNNEL_ENCAP_PSEUDOWIRE:
 	case __LWTUNNEL_ENCAP_MAX:
 		/* should not have got here */
 		WARN_ON(1);

net/mpls/Kconfig

@@ -27,6 +27,17 @@ config MPLS_ROUTING
 	---help---
 	 Add support for forwarding of mpls packets.
 
+config MPLS_VPLS
+	bool "VPLS support"
+	default y
+	depends on MPLS_ROUTING && BRIDGE_NETFILTER=n
+	---help---
+	 Add support for de-&encapsulating VPLS.  Not compatible with
+	 bridge netfilter due to the latter stomping over VPLS' dst metadata.
+
+comment "disable 'Bridged IP/ARP packets filtering' for VPLS support"
+	depends on BRIDGE_NETFILTER
+
 config MPLS_IPTUNNEL
 	tristate "MPLS: IP over MPLS tunnel support"
 	depends on LWTUNNEL && MPLS_ROUTING

net/mpls/Makefile

@@ -6,3 +6,4 @@ obj-$(CONFIG_MPLS_ROUTING) += mpls_router.o
 obj-$(CONFIG_MPLS_IPTUNNEL) += mpls_iptunnel.o
 
 mpls_router-y := af_mpls.o
+mpls_router-$(CONFIG_MPLS_VPLS) += vpls.o