datapath: ip6_gre: Fix ip6erspan hlen calculation

commit 2d665034f239412927b1e71329f20f001c92da09
Author: Petr Machata <petrm@mellanox.com>
Date:   Thu May 17 16:36:51 2018 +0200

    net: ip6_gre: Fix ip6erspan hlen calculation

    Even though ip6erspan_tap_init() sets up hlen and tun_hlen according to
    what ERSPAN needs, it goes ahead to call ip6gre_tnl_link_config() which
    overwrites these settings with GRE-specific ones.

    Similarly for changelink callbacks, which are handled by
    ip6gre_changelink() calls ip6gre_tnl_change() calls
    ip6gre_tnl_link_config() as well.

    The difference ends up being 12 vs. 20 bytes, and this is generally not
    a problem, because a 12-byte request likely ends up allocating more and
    the extra 8 bytes are thus available. However correct it is not.

    So replace the newlink and changelink callbacks with an ERSPAN-specific
    ones, reusing the newly-introduced _common() functions.

    Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
    Signed-off-by: Petr Machata <petrm@mellanox.com>
    Acked-by: William Tu <u9012063@gmail.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Reviewed-by: Greg Rose <gvrose8192@gmail.com>
Tested-by: Greg Rose <gvrose8192@gmail.com>

diff --git a/datapath/linux/compat/ip6_gre.c b/datapath/linux/compat/ip6_gre.c
index 7c06d732285c5c7bd1fcb679d9dc3862c4c9eb7d..3a82c3d0fc6bede6831758cb3603907f40ee7710 100644 (file)
--- a/datapath/linux/compat/ip6_gre.c
+++ b/datapath/linux/compat/ip6_gre.c
@@ -79,6 +79,7 @@ static int ip6gre_tunnel_init(struct net_device *dev);
 static void ip6gre_tunnel_setup(struct net_device *dev);
 static void ip6gre_tunnel_link(struct ip6gre_net *ign, struct ip6_tnl *t);
 static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu);
+static void ip6erspan_tnl_link_config(struct ip6_tnl *t, int set_mtu);
 
 #define gre_calc_hlen rpl_ip_gre_calc_hlen
 static int rpl_ip_gre_calc_hlen(__be16 o_flags)
@@ -1979,6 +1980,19 @@ static const struct net_device_ops ip6gre_tap_netdev_ops = {
 #endif
 };
 
+static int ip6erspan_calc_hlen(struct ip6_tnl *tunnel)
+{
+       int t_hlen;
+
+       tunnel->tun_hlen = 8;
+       tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
+                      erspan_hdr_len(tunnel->parms.erspan_ver);
+
+       t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
+       tunnel->dev->hard_header_len = LL_MAX_HEADER + t_hlen;
+       return t_hlen;
+}
+
 static int ip6erspan_tap_init(struct net_device *dev)
 {
        struct ip6_tnl *tunnel;
@@ -2002,12 +2016,7 @@ static int ip6erspan_tap_init(struct net_device *dev)
                return ret;
        }
 
-       tunnel->tun_hlen = 8;
-       tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
-                      erspan_hdr_len(tunnel->parms.erspan_ver);
-       t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
-
-       dev->hard_header_len = LL_MAX_HEADER + t_hlen;
+       t_hlen = ip6erspan_calc_hlen(tunnel);
        dev->mtu = ETH_DATA_LEN - t_hlen;
        if (dev->type == ARPHRD_ETHER)
                dev->mtu -= ETH_HLEN;
@@ -2016,7 +2025,7 @@ static int ip6erspan_tap_init(struct net_device *dev)
 
        dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
        tunnel = netdev_priv(dev);
-       ip6gre_tnl_link_config(tunnel, 1);
+       ip6erspan_tnl_link_config(tunnel, 1);
 
        return 0;
 }
@@ -2387,6 +2396,72 @@ static void ip6erspan_tap_setup(struct net_device *dev)
        netif_keep_dst(dev);
 }
 
+#ifdef HAVE_IP6GRE_EXTACK
+static int rpl_ip6erspan_newlink(struct net *src_net, struct net_device *dev,
+                                struct nlattr *tb[], struct nlattr *data[],
+                                struct netlink_ext_ack *extack)
+#else
+static int rpl_ip6erspan_newlink(struct net *src_net, struct net_device *dev,
+                                struct nlattr *tb[], struct nlattr *data[])
+#endif
+{
+#ifdef HAVE_IP6GRE_EXTACK
+       int err = ip6gre_newlink_common(src_net, dev, tb, data, extack);
+#else
+       int err = ip6gre_newlink_common(src_net, dev, tb, data);
+#endif
+       struct ip6_tnl *nt = netdev_priv(dev);
+       struct net *net = dev_net(dev);
+
+       if (!err) {
+               ip6erspan_tnl_link_config(nt, !tb[IFLA_MTU]);
+               ip6gre_tunnel_link(net_generic(net, ip6gre_net_id), nt);
+       }
+       return err;
+}
+#define ip6erspan_newlink rpl_ip6erspan_newlink
+
+static void ip6erspan_tnl_link_config(struct ip6_tnl *t, int set_mtu)
+{
+       ip6gre_tnl_link_config_common(t);
+       ip6gre_tnl_link_config_route(t, set_mtu, ip6erspan_calc_hlen(t));
+}
+
+static int ip6erspan_tnl_change(struct ip6_tnl *t,
+                               const struct __ip6_tnl_parm *p, int set_mtu)
+{
+       ip6gre_tnl_copy_tnl_parm(t, p);
+       ip6erspan_tnl_link_config(t, set_mtu);
+       return 0;
+}
+
+#ifdef HAVE_IP6GRE_EXTACK
+static int rpl_ip6erspan_changelink(struct net_device *dev, struct nlattr *tb[],
+                                   struct nlattr *data[],
+                                   struct netlink_ext_ack *extack)
+#else
+static int rpl_ip6erspan_changelink(struct net_device *dev, struct nlattr *tb[],
+                                   struct nlattr *data[])
+#endif
+{
+       struct ip6gre_net *ign = net_generic(dev_net(dev), ip6gre_net_id);
+       struct __ip6_tnl_parm p;
+       struct ip6_tnl *t;
+#ifdef HAVE_IP6GRE_EXTACK
+       t = ip6gre_changelink_common(dev, tb, data, &p, extack);
+#else
+       t = ip6gre_changelink_common(dev, tb, data, &p);
+#endif
+       if (IS_ERR(t))
+               return PTR_ERR(t);
+
+       ip6gre_tunnel_unlink(ign, t);
+       ip6erspan_tnl_change(t, &p, !tb[IFLA_MTU]);
+       ip6gre_tunnel_link(ign, t);
+       return 0;
+}
+#define ip6erspan_changelink rpl_ip6erspan_changelink
+
 static struct rtnl_link_ops ip6gre_link_ops __read_mostly = {
        .kind           = "ip6gre",
        .maxtype        = RPL_IFLA_GRE_MAX,
@@ -2428,8 +2503,8 @@ static struct rtnl_link_ops ip6erspan_tap_ops __read_mostly = {
        .priv_size      = sizeof(struct ip6_tnl),
        .setup          = ip6erspan_tap_setup,
        .validate       = ip6erspan_tap_validate,
-       .newlink        = ip6gre_newlink,
-       .changelink     = ip6gre_changelink,
+       .newlink        = ip6erspan_newlink,
+       .changelink     = ip6erspan_changelink,
        .dellink        = ip6gre_dellink,
        .get_size       = ip6gre_get_size,
        .fill_info      = ip6gre_fill_info,