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, 125 insertions, 0 deletions

diff --git a/include/linux/l2tp.h b/include/linux/l2tp.h
index deff7bca4e05..4bdb31df8e72 100644
--- a/include/linux/l2tp.h
+++ b/include/linux/l2tp.h
@@ -11,6 +11,8 @@
 #ifdef __KERNEL__
 #include <linux/socket.h>
 #include <linux/in.h>
+#else
+#include <netinet/in.h>
 #endif
 
 #define IPPROTO_L2TP		115
@@ -21,6 +23,7 @@
  * @l2tp_addr:    protocol specific address information
  * @l2tp_conn_id: connection id of tunnel
  */
+#define __SOCK_SIZE__	16		/* sizeof(struct sockaddr)	*/
 struct sockaddr_l2tpip {
 	/* The first fields must match struct sockaddr_in */
 	sa_family_t	l2tp_family;	/* AF_INET */
@@ -35,4 +38,126 @@ struct sockaddr_l2tpip {
 			      sizeof(__u32)];
 };
 
+/*****************************************************************************
+ *  NETLINK_GENERIC netlink family.
+ *****************************************************************************/
+
+/*
+ * Commands.
+ * Valid TLVs of each command are:-
+ * TUNNEL_CREATE	- CONN_ID, pw_type, netns, ifname, ipinfo, udpinfo, udpcsum, vlanid
+ * TUNNEL_DELETE	- CONN_ID
+ * TUNNEL_MODIFY	- CONN_ID, udpcsum
+ * TUNNEL_GETSTATS	- CONN_ID, (stats)
+ * TUNNEL_GET		- CONN_ID, (...)
+ * SESSION_CREATE	- SESSION_ID, PW_TYPE, offset, data_seq, cookie, peer_cookie, offset, l2spec
+ * SESSION_DELETE	- SESSION_ID
+ * SESSION_MODIFY	- SESSION_ID, data_seq
+ * SESSION_GET		- SESSION_ID, (...)
+ * SESSION_GETSTATS	- SESSION_ID, (stats)
+ *
+ */
+enum {
+	L2TP_CMD_NOOP,
+	L2TP_CMD_TUNNEL_CREATE,
+	L2TP_CMD_TUNNEL_DELETE,
+	L2TP_CMD_TUNNEL_MODIFY,
+	L2TP_CMD_TUNNEL_GET,
+	L2TP_CMD_SESSION_CREATE,
+	L2TP_CMD_SESSION_DELETE,
+	L2TP_CMD_SESSION_MODIFY,
+	L2TP_CMD_SESSION_GET,
+	__L2TP_CMD_MAX,
+};
+
+#define L2TP_CMD_MAX			(__L2TP_CMD_MAX - 1)
+
+/*
+ * ATTR types defined for L2TP
+ */
+enum {
+	L2TP_ATTR_NONE,			/* no data */
+	L2TP_ATTR_PW_TYPE,		/* u16, enum l2tp_pwtype */
+	L2TP_ATTR_ENCAP_TYPE,		/* u16, enum l2tp_encap_type */
+	L2TP_ATTR_OFFSET,		/* u16 */
+	L2TP_ATTR_DATA_SEQ,		/* u16 */
+	L2TP_ATTR_L2SPEC_TYPE,		/* u8, enum l2tp_l2spec_type */
+	L2TP_ATTR_L2SPEC_LEN,		/* u8, enum l2tp_l2spec_type */
+	L2TP_ATTR_PROTO_VERSION,	/* u8 */
+	L2TP_ATTR_IFNAME,		/* string */
+	L2TP_ATTR_CONN_ID,		/* u32 */
+	L2TP_ATTR_PEER_CONN_ID,		/* u32 */
+	L2TP_ATTR_SESSION_ID,		/* u32 */
+	L2TP_ATTR_PEER_SESSION_ID,	/* u32 */
+	L2TP_ATTR_UDP_CSUM,		/* u8 */
+	L2TP_ATTR_VLAN_ID,		/* u16 */
+	L2TP_ATTR_COOKIE,		/* 0, 4 or 8 bytes */
+	L2TP_ATTR_PEER_COOKIE,		/* 0, 4 or 8 bytes */
+	L2TP_ATTR_DEBUG,		/* u32 */
+	L2TP_ATTR_RECV_SEQ,		/* u8 */
+	L2TP_ATTR_SEND_SEQ,		/* u8 */
+	L2TP_ATTR_LNS_MODE,		/* u8 */
+	L2TP_ATTR_USING_IPSEC,		/* u8 */
+	L2TP_ATTR_RECV_TIMEOUT,		/* msec */
+	L2TP_ATTR_FD,			/* int */
+	L2TP_ATTR_IP_SADDR,		/* u32 */
+	L2TP_ATTR_IP_DADDR,		/* u32 */
+	L2TP_ATTR_UDP_SPORT,		/* u16 */
+	L2TP_ATTR_UDP_DPORT,		/* u16 */
+	L2TP_ATTR_MTU,			/* u16 */
+	L2TP_ATTR_MRU,			/* u16 */
+	L2TP_ATTR_STATS,		/* nested */
+	__L2TP_ATTR_MAX,
+};
+
+#define L2TP_ATTR_MAX			(__L2TP_ATTR_MAX - 1)
+
+/* Nested in L2TP_ATTR_STATS */
+enum {
+	L2TP_ATTR_STATS_NONE,		/* no data */
+	L2TP_ATTR_TX_PACKETS,		/* u64 */
+	L2TP_ATTR_TX_BYTES,		/* u64 */
+	L2TP_ATTR_TX_ERRORS,		/* u64 */
+	L2TP_ATTR_RX_PACKETS,		/* u64 */
+	L2TP_ATTR_RX_BYTES,		/* u64 */
+	L2TP_ATTR_RX_SEQ_DISCARDS,	/* u64 */
+	L2TP_ATTR_RX_OOS_PACKETS,	/* u64 */
+	L2TP_ATTR_RX_ERRORS,		/* u64 */
+	__L2TP_ATTR_STATS_MAX,
+};
+
+#define L2TP_ATTR_STATS_MAX		(__L2TP_ATTR_STATS_MAX - 1)
+
+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,
+};
+
+enum l2tp_seqmode {
+	L2TP_SEQ_NONE = 0,
+	L2TP_SEQ_IP = 1,
+	L2TP_SEQ_ALL = 2,
+};
+
+/*
+ * NETLINK_GENERIC related info
+ */
+#define L2TP_GENL_NAME		"l2tp"
+#define L2TP_GENL_VERSION	0x1
+
 #endif