l2tp: Add netlink control API for L2TP

In L2TPv3, we need to create/delete/modify/query L2TP tunnel and
session contexts. The number of parameters is significant. So let's
use netlink. Userspace uses this API to control L2TP tunnel/session
contexts in the kernel.

The previous pppol2tp driver was managed using [gs]etsockopt(). This
API is retained for backwards compatibility. Unlike L2TPv2 which
carries only PPP frames, L2TPv3 can carry raw ethernet frames or other
frame types and these do not always have an associated socket
family. Therefore, we need a way to use L2TP sessions that doesn't
require a socket type for each supported frame type. Hence netlink is
used.

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 20 deletions

diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index d239598..2974d9a 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -33,26 +33,6 @@ enum {
 	L2TP_MSG_DATA		= (1 << 3),	/* data packets */
 };
 
-enum l2tp_pwtype {
-	L2TP_PWTYPE_NONE = 0x0000,
-	L2TP_PWTYPE_ETH_VLAN = 0x0004,
-	L2TP_PWTYPE_ETH = 0x0005,
-	L2TP_PWTYPE_PPP = 0x0007,
-	L2TP_PWTYPE_PPP_AC = 0x0008,
-	L2TP_PWTYPE_IP = 0x000b,
-	__L2TP_PWTYPE_MAX
-};
-
-enum l2tp_l2spec_type {
-	L2TP_L2SPECTYPE_NONE,
-	L2TP_L2SPECTYPE_DEFAULT,
-};
-
-enum l2tp_encap_type {
-	L2TP_ENCAPTYPE_UDP,
-	L2TP_ENCAPTYPE_IP,
-};
-
 struct sk_buff;
 
 struct l2tp_stats {
@@ -87,6 +67,7 @@ struct l2tp_session_cfg {
 						 * control of LNS. */
 	int			debug;		/* bitmask of debug message
 						 * categories */
+	u16			vlan_id;	/* VLAN pseudowire only */
 	u16			offset;		/* offset to payload */
 	u16			l2specific_len;	/* Layer 2 specific length */
 	u16			l2specific_type; /* Layer 2 specific type */
@@ -98,6 +79,7 @@ struct l2tp_session_cfg {
 						  * (in jiffies) */
 	int			mtu;
 	int			mru;
+	char			*ifname;
 };
 
 struct l2tp_session {
@@ -124,6 +106,7 @@ struct l2tp_session {
 	atomic_t		ref_count;
 
 	char			name[32];	/* for logging */
+	char			ifname[IFNAMSIZ];
 	unsigned		data_seq:2;	/* data sequencing level
 						 * 0 => none, 1 => IP only,
 						 * 2 => all
@@ -192,6 +175,11 @@ struct l2tp_tunnel {
 	uint8_t			priv[0];	/* private data */
 };
 
+struct l2tp_nl_cmd_ops {
+	int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
+	int (*session_delete)(struct l2tp_session *session);
+};
+
 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 {
 	return &tunnel->priv[0];
@@ -224,11 +212,14 @@ out:
 
 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
+extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 
 extern int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp);
+extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 extern struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
+extern int l2tp_session_delete(struct l2tp_session *session);
 extern void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
 extern void l2tp_session_free(struct l2tp_session *session);
 extern void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, unsigned char *ptr, unsigned char *optr, u16 hdrflags, int length, int (*payload_hook)(struct sk_buff *skb));
@@ -241,6 +232,9 @@ extern void l2tp_tunnel_destruct(struct sock *sk);
 extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 extern void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 
+extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
+extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
+
 /* Tunnel reference counts. Incremented per session that is added to
  * the tunnel.
  */