sit: allow to configure 6rd tunnels via netlink

This patch add the support of 6RD tunnels management via netlink.
Note that netdev_state_change() is now called when 6RD parameters are updated.

6RD parameters are updated only if there is at least one 6RD attribute.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 128 insertions, 25 deletions

diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
index 5ab0c8ddc2bc..aee73d0611fb 100644
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h
@@ -49,6 +49,10 @@ enum {
         IFLA_IPTUN_FLAGS,
         IFLA_IPTUN_PROTO,
         IFLA_IPTUN_PMTUDISC,
+        IFLA_IPTUN_6RD_PREFIX,
+        IFLA_IPTUN_6RD_RELAY_PREFIX,
+        IFLA_IPTUN_6RD_PREFIXLEN,
+        IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
         __IFLA_IPTUN_MAX,
 };
 #define IFLA_IPTUN_MAX  (__IFLA_IPTUN_MAX - 1)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index fee21c6c3ebf..80cb3829831c 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -936,6 +936,38 @@ static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
         netdev_state_change(t->dev);
 }
 
+#ifdef CONFIG_IPV6_SIT_6RD
+static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
+                                   struct ip_tunnel_6rd *ip6rd)
+{
+        struct in6_addr prefix;
+        __be32 relay_prefix;
+
+        if (ip6rd->relay_prefixlen > 32 ||
+            ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
+                return -EINVAL;
+
+        ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
+        if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
+                return -EINVAL;
+        if (ip6rd->relay_prefixlen)
+                relay_prefix = ip6rd->relay_prefix &
+                               htonl(0xffffffffUL <<
+                                     (32 - ip6rd->relay_prefixlen));
+        else
+                relay_prefix = 0;
+        if (relay_prefix != ip6rd->relay_prefix)
+                return -EINVAL;
+
+        t->ip6rd.prefix = prefix;
+        t->ip6rd.relay_prefix = relay_prefix;
+        t->ip6rd.prefixlen = ip6rd->prefixlen;
+        t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
+        netdev_state_change(t->dev);
+        return 0;
+}
+#endif
+
 static int
 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 {
@@ -1105,31 +1137,9 @@ ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
                 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))
+                        err = ipip6_tunnel_update_6rd(t, &ip6rd);
+                        if (err < 0)
                                 goto done;
-                        if (ip6rd.relay_prefixlen)
-                                relay_prefix = ip6rd.relay_prefix &
-                                               htonl(0xffffffffUL <<
-                                                     (32 - ip6rd.relay_prefixlen));
-                        else
-                                relay_prefix = 0;
-                        if (relay_prefix != ip6rd.relay_prefix)
-                                goto done;
-
-                        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(dev, sitn);
 
@@ -1261,11 +1271,53 @@ static void ipip6_netlink_parms(struct nlattr *data[],
                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
 }
 
+#ifdef CONFIG_IPV6_SIT_6RD
+/* This function returns true when 6RD attributes are present in the nl msg */
+static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
+                                    struct ip_tunnel_6rd *ip6rd)
+{
+        bool ret = false;
+        memset(ip6rd, 0, sizeof(*ip6rd));
+
+        if (!data)
+                return ret;
+
+        if (data[IFLA_IPTUN_6RD_PREFIX]) {
+                ret = true;
+                nla_memcpy(&ip6rd->prefix, data[IFLA_IPTUN_6RD_PREFIX],
+                           sizeof(struct in6_addr));
+        }
+
+        if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
+                ret = true;
+                ip6rd->relay_prefix =
+                        nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
+        }
+
+        if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
+                ret = true;
+                ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
+        }
+
+        if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
+                ret = true;
+                ip6rd->relay_prefixlen =
+                        nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
+        }
+
+        return ret;
+}
+#endif
+
 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
                          struct nlattr *tb[], struct nlattr *data[])
 {
         struct net *net = dev_net(dev);
         struct ip_tunnel *nt;
+#ifdef CONFIG_IPV6_SIT_6RD
+        struct ip_tunnel_6rd ip6rd;
+#endif
+        int err;
 
         nt = netdev_priv(dev);
         ipip6_netlink_parms(data, &nt->parms);
@@ -1273,7 +1325,16 @@ static int ipip6_newlink(struct net *src_net, struct net_device *dev,
         if (ipip6_tunnel_locate(net, &nt->parms, 0))
                 return -EEXIST;
 
-        return ipip6_tunnel_create(dev);
+        err = ipip6_tunnel_create(dev);
+        if (err < 0)
+                return err;
+
+#ifdef CONFIG_IPV6_SIT_6RD
+        if (ipip6_netlink_6rd_parms(data, &ip6rd))
+                err = ipip6_tunnel_update_6rd(nt, &ip6rd);
+#endif
+
+        return err;
 }
 
 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
@@ -1283,6 +1344,9 @@ static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
         struct ip_tunnel_parm p;
         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
 
         if (dev == sitn->fb_tunnel_dev)
                 return -EINVAL;
@@ -1302,6 +1366,12 @@ static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
                 t = netdev_priv(dev);
 
         ipip6_tunnel_update(t, &p);
+
+#ifdef CONFIG_IPV6_SIT_6RD
+        if (ipip6_netlink_6rd_parms(data, &ip6rd))
+                return ipip6_tunnel_update_6rd(t, &ip6rd);
+#endif
+
         return 0;
 }
 
@@ -1322,6 +1392,16 @@ static size_t ipip6_get_size(const struct net_device *dev)
                 nla_total_size(1) +
                 /* IFLA_IPTUN_FLAGS */
                 nla_total_size(2) +
+#ifdef CONFIG_IPV6_SIT_6RD
+                /* IFLA_IPTUN_6RD_PREFIX */
+                nla_total_size(sizeof(struct in6_addr)) +
+                /* IFLA_IPTUN_6RD_RELAY_PREFIX */
+                nla_total_size(4) +
+                /* IFLA_IPTUN_6RD_PREFIXLEN */
+                nla_total_size(2) +
+                /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
+                nla_total_size(2) +
+#endif
                 0;
 }
 
@@ -1339,6 +1419,19 @@ static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
                        !!(parm->iph.frag_off & htons(IP_DF))) ||
             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
                 goto nla_put_failure;
+
+#ifdef CONFIG_IPV6_SIT_6RD
+        if (nla_put(skb, IFLA_IPTUN_6RD_PREFIX, sizeof(struct in6_addr),
+                    &tunnel->ip6rd.prefix) ||
+            nla_put_be32(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
+                         tunnel->ip6rd.relay_prefix) ||
+            nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
+                        tunnel->ip6rd.prefixlen) ||
+            nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
+                        tunnel->ip6rd.relay_prefixlen))
+                goto nla_put_failure;
+#endif
+
         return 0;
 
 nla_put_failure:
@@ -1353,6 +1446,12 @@ static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
+#ifdef CONFIG_IPV6_SIT_6RD
+        [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
+        [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
+        [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
+        [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
+#endif
 };
 
 static struct rtnl_link_ops sit_link_ops __read_mostly = {