2 files changed, 135 insertions, 8 deletions

diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index ead6c7a42f44..f56199827452 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -170,6 +170,25 @@ config IPV6_SIT
 
           Saying M here will produce a module called sit. If unsure, say Y.
 
+config IPV6_SIT_6RD
+        bool "IPv6: IPv6 Rapid Development (6RD) (EXPERIMENTAL)"
+        depends on IPV6_SIT && EXPERIMENTAL
+        default n
+        ---help---
+          IPv6 Rapid Deployment (6rd; draft-ietf-softwire-ipv6-6rd) builds upon
+          mechanisms of 6to4 (RFC3056) to enable a service provider to rapidly
+          deploy IPv6 unicast service to IPv4 sites to which it provides
+          customer premise equipment.  Like 6to4, it utilizes stateless IPv6 in
+          IPv4 encapsulation in order to transit IPv4-only network
+          infrastructure.  Unlike 6to4, a 6rd service provider uses an IPv6
+          prefix of its own in place of the fixed 6to4 prefix.
+
+          With this option enabled, the SIT driver offers 6rd functionality by
+          providing additional ioctl API to configure the IPv6 Prefix for in
+          stead of static 2002::/16 for 6to4.
+
+          If unsure, say N.
+
 config IPV6_NDISC_NODETYPE
         bool
 
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 99da272951dc..6955654262a5 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -161,6 +161,21 @@ static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
         write_unlock_bh(&ipip6_lock);
 }
 
+static void ipip6_tunnel_clone_6rd(struct ip_tunnel *t, struct sit_net *sitn)
+{
+#ifdef CONFIG_IPV6_SIT_6RD
+        if (t->dev == sitn->fb_tunnel_dev) {
+                ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
+                t->ip6rd.relay_prefix = 0;
+                t->ip6rd.prefixlen = 16;
+                t->ip6rd.relay_prefixlen = 0;
+        } else {
+                struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
+                memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
+        }
+#endif
+}
+
 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
                 struct ip_tunnel_parm *parms, int create)
 {
@@ -213,6 +228,8 @@ static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
 
         dev_hold(dev);
 
+        ipip6_tunnel_clone_6rd(t, sitn);
+
         ipip6_tunnel_link(sitn, nt);
         return nt;
 
@@ -532,17 +549,41 @@ out:
         return 0;
 }
 
-/* Returns the embedded IPv4 address if the IPv6 address
-   comes from 6to4 (RFC 3056) addr space */
-
-static inline __be32 try_6to4(struct in6_addr *v6dst)
+/*
+ * Returns the embedded IPv4 address if the IPv6 address
+ * comes from 6rd / 6to4 (RFC 3056) addr space.
+ */
+static inline
+__be32 try_6rd(struct in6_addr *v6dst, struct ip_tunnel *tunnel)
 {
         __be32 dst = 0;
 
+#ifdef CONFIG_IPV6_SIT_6RD
+        if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
+                              tunnel->ip6rd.prefixlen)) {
+                unsigned pbw0, pbi0;
+                int pbi1;
+                u32 d;
+
+                pbw0 = tunnel->ip6rd.prefixlen >> 5;
+                pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
+
+                d = (ntohl(tunnel->ip6rd.prefix.s6_addr32[pbw0]) << pbi0) >>
+                    tunnel->ip6rd.relay_prefixlen;
+
+                pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
+                if (pbi1 > 0)
+                        d |= ntohl(tunnel->ip6rd.prefix.s6_addr32[pbw0 + 1]) >>
+                             (32 - pbi1);
+
+                dst = tunnel->ip6rd.relay_prefix | htonl(d);
+        }
+#else
         if (v6dst->s6_addr16[0] == htons(0x2002)) {
                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
         }
+#endif
         return dst;
 }
 
@@ -596,7 +637,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
         }
 
         if (!dst)
-                dst = try_6to4(&iph6->daddr);
+                dst = try_6rd(&iph6->daddr, tunnel);
 
         if (!dst) {
                 struct neighbour *neigh = NULL;
@@ -786,9 +827,15 @@ ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
         struct ip_tunnel *t;
         struct net *net = dev_net(dev);
         struct sit_net *sitn = net_generic(net, sit_net_id);
+#ifdef CONFIG_IPV6_SIT_6RD
+        struct ip_tunnel_6rd ip6rd;
+#endif
 
         switch (cmd) {
         case SIOCGETTUNNEL:
+#ifdef CONFIG_IPV6_SIT_6RD
+        case SIOCGET6RD:
+#endif
                 t = NULL;
                 if (dev == sitn->fb_tunnel_dev) {
                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
@@ -799,9 +846,25 @@ ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
                 }
                 if (t == NULL)
                         t = netdev_priv(dev);
-                memcpy(&p, &t->parms, sizeof(p));
-                if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
-                        err = -EFAULT;
+
+                err = -EFAULT;
+                if (cmd == SIOCGETTUNNEL) {
+                        memcpy(&p, &t->parms, sizeof(p));
+                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
+                                         sizeof(p)))
+                                goto done;
+#ifdef CONFIG_IPV6_SIT_6RD
+                } else {
+                        ipv6_addr_copy(&ip6rd.prefix, &t->ip6rd.prefix);
+                        ip6rd.relay_prefix = t->ip6rd.relay_prefix;
+                        ip6rd.prefixlen = t->ip6rd.prefixlen;
+                        ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
+                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
+                                         sizeof(ip6rd)))
+                                goto done;
+#endif
+                }
+                err = 0;
                 break;
 
         case SIOCADDTUNNEL:
@@ -922,6 +985,51 @@ ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
                 netdev_state_change(dev);
                 break;
 
+#ifdef CONFIG_IPV6_SIT_6RD
+        case SIOCADD6RD:
+        case SIOCCHG6RD:
+        case SIOCDEL6RD:
+                err = -EPERM;
+                if (!capable(CAP_NET_ADMIN))
+                        goto done;
+
+                err = -EFAULT;
+                if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
+                                   sizeof(ip6rd)))
+                        goto done;
+
+                t = netdev_priv(dev);
+
+                if (cmd != SIOCDEL6RD) {
+                        struct in6_addr prefix;
+                        __be32 relay_prefix;
+
+                        err = -EINVAL;
+                        if (ip6rd.relay_prefixlen > 32 ||
+                            ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
+                                goto done;
+
+                        ipv6_addr_prefix(&prefix, &ip6rd.prefix,
+                                         ip6rd.prefixlen);
+                        if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
+                                goto done;
+                        relay_prefix = ip6rd.relay_prefix &
+                                       htonl(0xffffffffUL <<
+                                             (32 - ip6rd.relay_prefixlen));
+                        if (relay_prefix != ip6rd.relay_prefix)
+                                goto done;
+
+                        ipv6_addr_copy(&t->ip6rd.prefix, &prefix);
+                        t->ip6rd.relay_prefix = relay_prefix;
+                        t->ip6rd.prefixlen = ip6rd.prefixlen;
+                        t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
+                } else
+                        ipip6_tunnel_clone_6rd(t, sitn);
+
+                err = 0;
+                break;
+#endif
+
         default:
                 err = -EINVAL;
         }