Commit 2d665034 authored by Petr Machata's avatar Petr Machata Committed by David S. Miller
Browse files

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: 5a963eb6 ("ip6_gre: Add ERSPAN native tunnel support")
Signed-off-by: default avatarPetr Machata <petrm@mellanox.com>
Acked-by: default avatarWilliam Tu <u9012063@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c8632fc3

net/ipv6/ip6_gre.c

+65 −9
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ 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);



/* Tunnel hash table */
@@ -1754,6 +1755,19 @@ static const struct net_device_ops ip6gre_tap_netdev_ops = { 
	.ndo_get_iflink = ip6_tnl_get_iflink,

};



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;
@@ -1777,12 +1791,7 @@ 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;
@@ -1790,7 +1799,7 @@ static int ip6erspan_tap_init(struct net_device *dev) 
		dev->mtu -= 8;



	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;

	ip6gre_tnl_link_config(tunnel, 1);

	ip6erspan_tnl_link_config(tunnel, 1);



	return 0;

}
@@ -2121,6 +2130,53 @@ static void ip6erspan_tap_setup(struct net_device *dev) 
	netif_keep_dst(dev);

}



static int ip6erspan_newlink(struct net *src_net, struct net_device *dev,

			     struct nlattr *tb[], struct nlattr *data[],

			     struct netlink_ext_ack *extack)

{

	int err = ip6gre_newlink_common(src_net, dev, tb, data, extack);

	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;

}



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;

}



static int ip6erspan_changelink(struct net_device *dev, struct nlattr *tb[],

				struct nlattr *data[],

				struct netlink_ext_ack *extack)

{

	struct ip6gre_net *ign = net_generic(dev_net(dev), ip6gre_net_id);

	struct __ip6_tnl_parm p;

	struct ip6_tnl *t;



	t = ip6gre_changelink_common(dev, tb, data, &p, extack);

	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;

}



static struct rtnl_link_ops ip6gre_link_ops __read_mostly = {

	.kind		= "ip6gre",

	.maxtype	= IFLA_GRE_MAX,
@@ -2157,8 +2213,8 @@ 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,

	.get_size	= ip6gre_get_size,

	.fill_info	= ip6gre_fill_info,

	.get_link_net	= ip6_tnl_get_link_net,

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