l2tp: let iproute2 create L2TPv3 IP tunnels using IPv6

The netlink API lets users create unmanaged L2TPv3 tunnels using
iproute2. Until now, a request to create an unmanaged L2TPv3 IP
encapsulation tunnel over IPv6 would be rejected with
EPROTONOSUPPORT. Now that l2tp_ip6 implements sockets for L2TP IP
encapsulation over IPv6, we can add support for that tunnel type.

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

1 files changed, 50 insertions, 22 deletions

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 55fc569c8170..456b52d8f6d8 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1368,6 +1368,7 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
         struct sockaddr_in udp_addr;
 #if IS_ENABLED(CONFIG_IPV6)
         struct sockaddr_in6 udp6_addr;
+        struct sockaddr_l2tpip6 ip6_addr;
 #endif
         struct sockaddr_l2tpip ip_addr;
         struct socket *sock = NULL;
@@ -1437,32 +1438,59 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
         case L2TP_ENCAPTYPE_IP:
 #if IS_ENABLED(CONFIG_IPV6)
                 if (cfg->local_ip6 && cfg->peer_ip6) {
-                        /* IP encap over IPv6 not yet supported */
-                        err = -EPROTONOSUPPORT;
-                        goto out;
-                }
-#endif
-                err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
-                if (err < 0)
-                        goto out;
+                        err = sock_create(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP,
+                                          sockp);
+                        if (err < 0)
+                                goto out;
 
-                sock = *sockp;
+                        sock = *sockp;
 
-                memset(&ip_addr, 0, sizeof(ip_addr));
-                ip_addr.l2tp_family = AF_INET;
-                ip_addr.l2tp_addr = cfg->local_ip;
-                ip_addr.l2tp_conn_id = tunnel_id;
-                err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr));
-                if (err < 0)
-                        goto out;
+                        memset(&ip6_addr, 0, sizeof(ip6_addr));
+                        ip6_addr.l2tp_family = AF_INET6;
+                        memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
+                               sizeof(ip6_addr.l2tp_addr));
+                        ip6_addr.l2tp_conn_id = tunnel_id;
+                        err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
+                                          sizeof(ip6_addr));
+                        if (err < 0)
+                                goto out;
 
-                ip_addr.l2tp_family = AF_INET;
-                ip_addr.l2tp_addr = cfg->peer_ip;
-                ip_addr.l2tp_conn_id = peer_tunnel_id;
-                err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0);
-                if (err < 0)
-                        goto out;
+                        ip6_addr.l2tp_family = AF_INET6;
+                        memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
+                               sizeof(ip6_addr.l2tp_addr));
+                        ip6_addr.l2tp_conn_id = peer_tunnel_id;
+                        err = kernel_connect(sock,
+                                             (struct sockaddr *) &ip6_addr,
+                                             sizeof(ip6_addr), 0);
+                        if (err < 0)
+                                goto out;
+                } else
+#endif
+                {
+                        err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP,
+                                          sockp);
+                        if (err < 0)
+                                goto out;
 
+                        sock = *sockp;
+
+                        memset(&ip_addr, 0, sizeof(ip_addr));
+                        ip_addr.l2tp_family = AF_INET;
+                        ip_addr.l2tp_addr = cfg->local_ip;
+                        ip_addr.l2tp_conn_id = tunnel_id;
+                        err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
+                                          sizeof(ip_addr));
+                        if (err < 0)
+                                goto out;
+
+                        ip_addr.l2tp_family = AF_INET;
+                        ip_addr.l2tp_addr = cfg->peer_ip;
+                        ip_addr.l2tp_conn_id = peer_tunnel_id;
+                        err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
+                                             sizeof(ip_addr), 0);
+                        if (err < 0)
+                                goto out;
+                }
                 break;
 
         default: