sit: support MPLS over IPv4

Extend the SIT driver to support MPLS over IPv4. This implementation
extends existing support for IPv6 over IPv4 and IPv4 over IPv4.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Dinan Gunawardena <dinan.gunawardena@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 917a5cd4b8fc79bb129ba8a004d1a877decef354..182b6a9be29dfba5514bb74c840afb36cbc367b0 100644 (file)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -688,12 +688,19 @@ out:
        return 0;
 }
 
-static const struct tnl_ptk_info tpi = {
+static const struct tnl_ptk_info ipip_tpi = {
        /* no tunnel info required for ipip. */
        .proto = htons(ETH_P_IP),
 };
 
-static int ipip_rcv(struct sk_buff *skb)
+#if IS_ENABLED(CONFIG_MPLS)
+static const struct tnl_ptk_info mplsip_tpi = {
+       /* no tunnel info required for mplsip. */
+       .proto = htons(ETH_P_MPLS_UC),
+};
+#endif
+
+static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
 {
        const struct iphdr *iph;
        struct ip_tunnel *tunnel;
@@ -702,15 +709,23 @@ static int ipip_rcv(struct sk_buff *skb)
        tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
                                     iph->saddr, iph->daddr);
        if (tunnel) {
-               if (tunnel->parms.iph.protocol != IPPROTO_IPIP &&
+               const struct tnl_ptk_info *tpi;
+
+               if (tunnel->parms.iph.protocol != ipproto &&
                    tunnel->parms.iph.protocol != 0)
                        goto drop;
 
                if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
                        goto drop;
-               if (iptunnel_pull_header(skb, 0, tpi.proto, false))
+#if IS_ENABLED(CONFIG_MPLS)
+               if (ipproto == IPPROTO_MPLS)
+                       tpi = &mplsip_tpi;
+               else
+#endif
+                       tpi = &ipip_tpi;
+               if (iptunnel_pull_header(skb, 0, tpi->proto, false))
                        goto drop;
-               return ip_tunnel_rcv(tunnel, skb, &tpi, NULL, log_ecn_error);
+               return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
        }
 
        return 1;
@@ -720,6 +735,18 @@ drop:
        return 0;
 }
 
+static int ipip_rcv(struct sk_buff *skb)
+{
+       return sit_tunnel_rcv(skb, IPPROTO_IPIP);
+}
+
+#if IS_ENABLED(CONFIG_MPLS)
+static int mplsip_rcv(struct sk_buff *skb)
+{
+       return sit_tunnel_rcv(skb, IPPROTO_MPLS);
+}
+#endif
+
 /*
  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
  * stores the embedded IPv4 address in v4dst and returns true.
@@ -958,7 +985,8 @@ tx_error:
        return NETDEV_TX_OK;
 }
 
-static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
+                                    struct net_device *dev, u8 ipproto)
 {
        struct ip_tunnel *tunnel = netdev_priv(dev);
        const struct iphdr  *tiph = &tunnel->parms.iph;
@@ -966,9 +994,9 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
        if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
                goto tx_error;
 
-       skb_set_inner_ipproto(skb, IPPROTO_IPIP);
+       skb_set_inner_ipproto(skb, ipproto);
 
-       ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
+       ip_tunnel_xmit(skb, dev, tiph, ipproto);
        return NETDEV_TX_OK;
 tx_error:
        kfree_skb(skb);
@@ -981,11 +1009,16 @@ static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
 {
        switch (skb->protocol) {
        case htons(ETH_P_IP):
-               ipip_tunnel_xmit(skb, dev);
+               sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
                break;
        case htons(ETH_P_IPV6):
                ipip6_tunnel_xmit(skb, dev);
                break;
+#if IS_ENABLED(CONFIG_MPLS)
+       case htons(ETH_P_MPLS_UC):
+               sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
+               break;
+#endif
        default:
                goto tx_err;
        }
@@ -1093,6 +1126,16 @@ static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
 }
 #endif
 
+bool ipip6_valid_ip_proto(u8 ipproto)
+{
+       return ipproto == IPPROTO_IPV6 ||
+               ipproto == IPPROTO_IPIP ||
+#if IS_ENABLED(CONFIG_MPLS)
+               ipproto == IPPROTO_MPLS ||
+#endif
+               ipproto == 0;
+}
+
 static int
 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 {
@@ -1152,9 +1195,7 @@ ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
                        goto done;
 
                err = -EINVAL;
-               if (p.iph.protocol != IPPROTO_IPV6 &&
-                   p.iph.protocol != IPPROTO_IPIP &&
-                   p.iph.protocol != 0)
+               if (!ipip6_valid_ip_proto(p.iph.protocol))
                        goto done;
                if (p.iph.version != 4 ||
                    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
@@ -1379,9 +1420,7 @@ static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
                return 0;
 
        proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
-       if (proto != IPPROTO_IPV6 &&
-           proto != IPPROTO_IPIP &&
-           proto != 0)
+       if (!ipip6_valid_ip_proto(proto))
                return -EINVAL;
 
        return 0;
@@ -1723,6 +1762,14 @@ static struct xfrm_tunnel ipip_handler __read_mostly = {
        .priority       =       2,
 };
 
+#if IS_ENABLED(CONFIG_MPLS)
+static struct xfrm_tunnel mplsip_handler __read_mostly = {
+       .handler        =       mplsip_rcv,
+       .err_handler    =       ipip6_err,
+       .priority       =       2,
+};
+#endif
+
 static void __net_exit sit_destroy_tunnels(struct net *net,
                                           struct list_head *head)
 {
@@ -1818,6 +1865,9 @@ static void __exit sit_cleanup(void)
        rtnl_link_unregister(&sit_link_ops);
        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
        xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
+#if IS_ENABLED(CONFIG_MPLS)
+       xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
+#endif
 
        unregister_pernet_device(&sit_net_ops);
        rcu_barrier(); /* Wait for completion of call_rcu()'s */
@@ -1827,7 +1877,7 @@ static int __init sit_init(void)
 {
        int err;
 
-       pr_info("IPv6 over IPv4 tunneling driver\n");
+       pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
 
        err = register_pernet_device(&sit_net_ops);
        if (err < 0)
@@ -1842,6 +1892,13 @@ static int __init sit_init(void)
                pr_info("%s: can't register ip4ip4\n", __func__);
                goto xfrm_tunnel4_failed;
        }
+#if IS_ENABLED(CONFIG_MPLS)
+       err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
+       if (err < 0) {
+               pr_info("%s: can't register mplsip\n", __func__);
+               goto xfrm_tunnel_mpls_failed;
+       }
+#endif
        err = rtnl_link_register(&sit_link_ops);
        if (err < 0)
                goto rtnl_link_failed;
@@ -1850,6 +1907,10 @@ out:
        return err;
 
 rtnl_link_failed:
+#if IS_ENABLED(CONFIG_MPLS)
+       xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
+xfrm_tunnel_mpls_failed:
+#endif
        xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
 xfrm_tunnel4_failed:
        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);