l2tp: netlink api for l2tpv3 ipv6 unmanaged tunnels

This patch adds support for unmanaged L2TPv3 tunnels over IPv6 using
the netlink API. We already support unmanaged L2TPv3 tunnels over
IPv4. A patch to iproute2 to make use of this feature will be
submitted separately.

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

1 files changed, 61 insertions, 17 deletions

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index f1bfae3e1ba6..55fc569c8170 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1366,31 +1366,68 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
 {
         int err = -EINVAL;
         struct sockaddr_in udp_addr;
+#if IS_ENABLED(CONFIG_IPV6)
+        struct sockaddr_in6 udp6_addr;
+#endif
         struct sockaddr_l2tpip ip_addr;
         struct socket *sock = NULL;
 
         switch (cfg->encap) {
         case L2TP_ENCAPTYPE_UDP:
-                err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
-                if (err < 0)
-                        goto out;
+#if IS_ENABLED(CONFIG_IPV6)
+                if (cfg->local_ip6 && cfg->peer_ip6) {
+                        err = sock_create(AF_INET6, SOCK_DGRAM, 0, sockp);
+                        if (err < 0)
+                                goto out;
 
-                sock = *sockp;
+                        sock = *sockp;
 
-                memset(&udp_addr, 0, sizeof(udp_addr));
-                udp_addr.sin_family = AF_INET;
-                udp_addr.sin_addr = cfg->local_ip;
-                udp_addr.sin_port = htons(cfg->local_udp_port);
-                err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr));
-                if (err < 0)
-                        goto out;
+                        memset(&udp6_addr, 0, sizeof(udp6_addr));
+                        udp6_addr.sin6_family = AF_INET6;
+                        memcpy(&udp6_addr.sin6_addr, cfg->local_ip6,
+                               sizeof(udp6_addr.sin6_addr));
+                        udp6_addr.sin6_port = htons(cfg->local_udp_port);
+                        err = kernel_bind(sock, (struct sockaddr *) &udp6_addr,
+                                          sizeof(udp6_addr));
+                        if (err < 0)
+                                goto out;
 
-                udp_addr.sin_family = AF_INET;
-                udp_addr.sin_addr = cfg->peer_ip;
-                udp_addr.sin_port = htons(cfg->peer_udp_port);
-                err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0);
-                if (err < 0)
-                        goto out;
+                        udp6_addr.sin6_family = AF_INET6;
+                        memcpy(&udp6_addr.sin6_addr, cfg->peer_ip6,
+                               sizeof(udp6_addr.sin6_addr));
+                        udp6_addr.sin6_port = htons(cfg->peer_udp_port);
+                        err = kernel_connect(sock,
+                                             (struct sockaddr *) &udp6_addr,
+                                             sizeof(udp6_addr), 0);
+                        if (err < 0)
+                                goto out;
+                } else
+#endif
+                {
+                        err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
+                        if (err < 0)
+                                goto out;
+
+                        sock = *sockp;
+
+                        memset(&udp_addr, 0, sizeof(udp_addr));
+                        udp_addr.sin_family = AF_INET;
+                        udp_addr.sin_addr = cfg->local_ip;
+                        udp_addr.sin_port = htons(cfg->local_udp_port);
+                        err = kernel_bind(sock, (struct sockaddr *) &udp_addr,
+                                          sizeof(udp_addr));
+                        if (err < 0)
+                                goto out;
+
+                        udp_addr.sin_family = AF_INET;
+                        udp_addr.sin_addr = cfg->peer_ip;
+                        udp_addr.sin_port = htons(cfg->peer_udp_port);
+                        err = kernel_connect(sock,
+                                             (struct sockaddr *) &udp_addr,
+                                             sizeof(udp_addr), 0);
+                        if (err < 0)
+                                goto out;
+                }
 
                 if (!cfg->use_udp_checksums)
                         sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
@@ -1398,6 +1435,13 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
                 break;
 
         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;