[L2TP]: Changes to existing ppp and socket kernel headers for L2TP

Add struct sockaddr_pppol2tp to carry L2TP-specific address
information for the PPPoX (PPPoL2TP) socket. Unfortunately we can't
use the union inside struct sockaddr_pppox because the L2TP-specific
data is larger than the current size of the union and we must preserve
the size of struct sockaddr_pppox for binary compatibility.

Also add a PPPIOCGL2TPSTATS ioctl to allow userspace to obtain
L2TP counters and state from the kernel.

Add new if_pppol2tp.h header.

[ Modified to use aligned_u64 in statistics structure -DaveM ]

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 2 deletions

diff --git a/include/linux/if_pppox.h b/include/linux/if_pppox.h
index 6f987be60fe2..25652545ba6e 100644
--- a/include/linux/if_pppox.h
+++ b/include/linux/if_pppox.h
@@ -27,6 +27,7 @@
 #include <asm/semaphore.h>
 #include <linux/ppp_channel.h>
 #endif /* __KERNEL__ */
+#include <linux/if_pppol2tp.h>
 
 /* For user-space programs to pick up these definitions
  * which they wouldn't get otherwise without defining __KERNEL__
@@ -50,8 +51,9 @@ struct pppoe_addr{
  * Protocols supported by AF_PPPOX 
  */ 
 #define PX_PROTO_OE    0 /* Currently just PPPoE */
-#define PX_MAX_PROTO   1        
- 
+#define PX_PROTO_OL2TP 1 /* Now L2TP also */
+#define PX_MAX_PROTO   2
+
 struct sockaddr_pppox { 
        sa_family_t     sa_family;            /* address family, AF_PPPOX */ 
        unsigned int    sa_protocol;          /* protocol identifier */ 
@@ -60,6 +62,16 @@ struct sockaddr_pppox {
        }sa_addr; 
 }__attribute__ ((packed)); 
 
+/* The use of the above union isn't viable because the size of this
+ * struct must stay fixed over time -- applications use sizeof(struct
+ * sockaddr_pppox) to fill it. We use a protocol specific sockaddr
+ * type instead.
+ */
+struct sockaddr_pppol2tp {
+        sa_family_t     sa_family;      /* address family, AF_PPPOX */
+        unsigned int    sa_protocol;    /* protocol identifier */
+        struct pppol2tp_addr pppol2tp;
+}__attribute__ ((packed));
 
 /*********************************************************************
  *