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>

3 files changed, 109 insertions, 21 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;
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index a8c943bf4140..0bf60fc88bb7 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -151,6 +151,10 @@ struct l2tp_tunnel_cfg {
         /* Used only for kernel-created sockets */
         struct in_addr          local_ip;
         struct in_addr          peer_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+        struct in6_addr         *local_ip6;
+        struct in6_addr         *peer_ip6;
+#endif
         u16                     local_udp_port;
         u16                     peer_udp_port;
         unsigned int            use_udp_checksums:1;
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 1dbb9772fc45..24edad0fd9ba 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -133,10 +133,25 @@ static int l2tp_nl_cmd_tunnel_create(struct sk_buff *skb, struct genl_info *info
         if (info->attrs[L2TP_ATTR_FD]) {
                 fd = nla_get_u32(info->attrs[L2TP_ATTR_FD]);
         } else {
-                if (info->attrs[L2TP_ATTR_IP_SADDR])
-                        cfg.local_ip.s_addr = nla_get_be32(info->attrs[L2TP_ATTR_IP_SADDR]);
-                if (info->attrs[L2TP_ATTR_IP_DADDR])
-                        cfg.peer_ip.s_addr = nla_get_be32(info->attrs[L2TP_ATTR_IP_DADDR]);
+#if IS_ENABLED(CONFIG_IPV6)
+                if (info->attrs[L2TP_ATTR_IP6_SADDR] &&
+                    info->attrs[L2TP_ATTR_IP6_DADDR]) {
+                        cfg.local_ip6 = nla_data(
+                                info->attrs[L2TP_ATTR_IP6_SADDR]);
+                        cfg.peer_ip6 = nla_data(
+                                info->attrs[L2TP_ATTR_IP6_DADDR]);
+                } else
+#endif
+                if (info->attrs[L2TP_ATTR_IP_SADDR] &&
+                    info->attrs[L2TP_ATTR_IP_DADDR]) {
+                        cfg.local_ip.s_addr = nla_get_be32(
+                                info->attrs[L2TP_ATTR_IP_SADDR]);
+                        cfg.peer_ip.s_addr = nla_get_be32(
+                                info->attrs[L2TP_ATTR_IP_DADDR]);
+                } else {
+                        ret = -EINVAL;
+                        goto out;
+                }
                 if (info->attrs[L2TP_ATTR_UDP_SPORT])
                         cfg.local_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_SPORT]);
                 if (info->attrs[L2TP_ATTR_UDP_DPORT])
@@ -225,6 +240,9 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
         struct nlattr *nest;
         struct sock *sk = NULL;
         struct inet_sock *inet;
+#if IS_ENABLED(CONFIG_IPV6)
+        struct ipv6_pinfo *np = NULL;
+#endif
         struct l2tp_stats stats;
         unsigned int start;
 
@@ -273,6 +291,11 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
         if (!sk)
                 goto out;
 
+#if IS_ENABLED(CONFIG_IPV6)
+        if (sk->sk_family == AF_INET6)
+                np = inet6_sk(sk);
+#endif
+
         inet = inet_sk(sk);
 
         switch (tunnel->encap) {
@@ -284,6 +307,15 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
                         goto nla_put_failure;
                 /* NOBREAK */
         case L2TP_ENCAPTYPE_IP:
+#if IS_ENABLED(CONFIG_IPV6)
+                if (np) {
+                        if (nla_put(skb, L2TP_ATTR_IP6_SADDR, sizeof(np->saddr),
+                                    &np->saddr) ||
+                            nla_put(skb, L2TP_ATTR_IP6_DADDR, sizeof(np->daddr),
+                                    &np->daddr))
+                                goto nla_put_failure;
+                } else
+#endif
                 if (nla_put_be32(skb, L2TP_ATTR_IP_SADDR, inet->inet_saddr) ||
                     nla_put_be32(skb, L2TP_ATTR_IP_DADDR, inet->inet_daddr))
                         goto nla_put_failure;
@@ -752,6 +784,14 @@ static struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
         [L2TP_ATTR_MTU]                 = { .type = NLA_U16, },
         [L2TP_ATTR_MRU]                 = { .type = NLA_U16, },
         [L2TP_ATTR_STATS]               = { .type = NLA_NESTED, },
+        [L2TP_ATTR_IP6_SADDR] = {
+                .type = NLA_BINARY,
+                .len = sizeof(struct in6_addr),
+        },
+        [L2TP_ATTR_IP6_DADDR] = {
+                .type = NLA_BINARY,
+                .len = sizeof(struct in6_addr),
+        },
         [L2TP_ATTR_IFNAME] = {
                 .type = NLA_NUL_STRING,
                 .len = IFNAMSIZ - 1,