l2tp: Update PPP-over-L2TP driver to work over L2TPv3

This patch makes changes to the L2TP PPP code for L2TPv3.

The existing code has some assumptions about the L2TP header which are
broken by L2TPv3. Also the sockaddr_pppol2tp structure of the original
code is too small to support the increased size of the L2TPv3 tunnel
and session id, so a new sockaddr_pppol2tpv3 structure is needed. In
the socket calls, the size of this structure is used to tell if the
operation is for L2TPv2 or L2TPv3.

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>

2 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/if_pppol2tp.h b/include/linux/if_pppol2tp.h
index 1a1fb6e..184bc55 100644
--- a/include/linux/if_pppol2tp.h
+++ b/include/linux/if_pppol2tp.h
@@ -35,6 +35,20 @@ struct pppol2tp_addr {
 	__u16 d_tunnel, d_session;	/* For sending outgoing packets */
 };
 
+/* The L2TPv3 protocol changes tunnel and session ids from 16 to 32
+ * bits. So we need a different sockaddr structure.
+ */
+struct pppol2tpv3_addr {
+	pid_t	pid;			/* pid that owns the fd.
+					 * 0 => current */
+	int	fd;			/* FD of UDP or IP socket to use */
+
+	struct sockaddr_in addr;	/* IP address and port to send to */
+
+	__u32 s_tunnel, s_session;	/* For matching incoming packets */
+	__u32 d_tunnel, d_session;	/* For sending outgoing packets */
+};
+
 /* Socket options:
  * DEBUG	- bitmask of debug message categories
  * SENDSEQ	- 0 => don't send packets with sequence numbers
diff --git a/include/linux/if_pppox.h b/include/linux/if_pppox.h
index 90b5fae..a6577af 100644
--- a/include/linux/if_pppox.h
+++ b/include/linux/if_pppox.h
@@ -72,6 +72,15 @@ struct sockaddr_pppol2tp {
 	struct pppol2tp_addr pppol2tp;
 }__attribute__ ((packed));
 
+/* The L2TPv3 protocol changes tunnel and session ids from 16 to 32
+ * bits. So we need a different sockaddr structure.
+ */
+struct sockaddr_pppol2tpv3 {
+	sa_family_t     sa_family;      /* address family, AF_PPPOX */
+	unsigned int    sa_protocol;    /* protocol identifier */
+	struct pppol2tpv3_addr pppol2tp;
+} __attribute__ ((packed));
+
 /*********************************************************************
  *
  * ioctl interface for defining forwarding of connections