l2tp: Add L2TPv3 protocol support

The L2TPv3 protocol changes the layout of the L2TP packet
header. Tunnel and session ids change from 16-bit to 32-bit values,
data sequence numbers change from 16-bit to 24-bit values and PPP-specific
fields are moved into protocol-specific subheaders.

Although this patch introduces L2TPv3 protocol support, there are no
userspace interfaces to create L2TPv3 sessions yet.

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, 16 insertions, 5 deletions

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 3ad290dd830a..bee5b1413ec0 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -670,7 +670,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 
         /* Check that this session doesn't already exist */
         error = -EEXIST;
-        session = l2tp_session_find(tunnel, sp->pppol2tp.s_session);
+        session = l2tp_session_find(sock_net(sk), tunnel, sp->pppol2tp.s_session);
         if (session != NULL)
                 goto end;
 
@@ -678,7 +678,6 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
          * headers.
          */
         cfg.mtu = cfg.mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
-        cfg.hdr_len = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
         cfg.debug = tunnel->debug;
 
         /* Allocate and initialize a new session context. */
@@ -999,7 +998,7 @@ static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
                 if (stats.session_id != 0) {
                         /* resend to session ioctl handler */
                         struct l2tp_session *session =
-                                l2tp_session_find(tunnel, stats.session_id);
+                                l2tp_session_find(sock_net(sk), tunnel, stats.session_id);
                         if (session != NULL)
                                 err = pppol2tp_session_ioctl(session, cmd, arg);
                         else
@@ -1375,6 +1374,8 @@ end:
 
 /*****************************************************************************
  * /proc filesystem for debug
+ * Since the original pppol2tp driver provided /proc/net/pppol2tp for
+ * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
  *****************************************************************************/
 
 static unsigned int pppol2tp_net_id;
@@ -1391,14 +1392,24 @@ struct pppol2tp_seq_data {
 
 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
 {
-        pd->tunnel = l2tp_tunnel_find_nth(net, pd->tunnel_idx);
-        pd->tunnel_idx++;
+        for (;;) {
+                pd->tunnel = l2tp_tunnel_find_nth(net, pd->tunnel_idx);
+                pd->tunnel_idx++;
+
+                if (pd->tunnel == NULL)
+                        break;
+
+                /* Ignore L2TPv3 tunnels */
+                if (pd->tunnel->version < 3)
+                        break;
+        }
 }
 
 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
 {
         pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
         pd->session_idx++;
+
         if (pd->session == NULL) {
                 pd->session_idx = 0;
                 pppol2tp_next_tunnel(net, pd);