Commit e1f8f78f authored by Petr Machata's avatar Petr Machata Committed by David S. Miller
Browse files

net: ip_gre: Separate ERSPAN newlink / changelink callbacks 



ERSPAN shares most of the code path with GRE and gretap code. While that
helps keep the code compact, it is also error prone. Currently a broken
userspace can turn a gretap tunnel into a de facto ERSPAN one by passing
IFLA_GRE_ERSPAN_VER. There has been a similar issue in ip6gretap in the
past.

To prevent these problems in future, split the newlink and changelink code
paths. Split the ERSPAN code out of ipgre_netlink_parms() into a new
function erspan_netlink_parms(). Extract a piece of common logic from
ipgre_newlink() and ipgre_changelink() into ipgre_newlink_encap_setup().
Add erspan_newlink() and erspan_changelink().

Fixes: 84e54fe0 ("gre: introduce native tunnel support for ERSPAN")
Signed-off-by: default avatarPetr Machata <petrm@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 46ea929b

net/ipv4/ip_gre.c

+85 −18
Original line number Diff line number Diff line
@@ -1153,6 +1153,22 @@ static int ipgre_netlink_parms(struct net_device *dev, 
	if (data[IFLA_GRE_FWMARK])

		*fwmark = nla_get_u32(data[IFLA_GRE_FWMARK]);



	return 0;

}



static int erspan_netlink_parms(struct net_device *dev,

				struct nlattr *data[],

				struct nlattr *tb[],

				struct ip_tunnel_parm *parms,

				__u32 *fwmark)

{

	struct ip_tunnel *t = netdev_priv(dev);

	int err;



	err = ipgre_netlink_parms(dev, data, tb, parms, fwmark);

	if (err)

		return err;



	if (data[IFLA_GRE_ERSPAN_VER]) {

		t->erspan_ver = nla_get_u8(data[IFLA_GRE_ERSPAN_VER]);
@@ -1276,25 +1292,54 @@ static void ipgre_tap_setup(struct net_device *dev) 
	ip_tunnel_setup(dev, gre_tap_net_id);

}



static int

ipgre_newlink_encap_setup(struct net_device *dev, struct nlattr *data[])

{

	struct ip_tunnel_encap ipencap;



	if (ipgre_netlink_encap_parms(data, &ipencap)) {

		struct ip_tunnel *t = netdev_priv(dev);

		int err = ip_tunnel_encap_setup(t, &ipencap);



		if (err < 0)

			return err;

	}



	return 0;

}



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

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

			 struct netlink_ext_ack *extack)

{

	struct ip_tunnel_parm p;

	struct ip_tunnel_encap ipencap;

	__u32 fwmark = 0;

	int err;



	if (ipgre_netlink_encap_parms(data, &ipencap)) {

		struct ip_tunnel *t = netdev_priv(dev);

		err = ip_tunnel_encap_setup(t, &ipencap);

	err = ipgre_newlink_encap_setup(dev, data);

	if (err)

		return err;



	err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);

	if (err < 0)

		return err;

	return ip_tunnel_newlink(dev, tb, &p, fwmark);

}



	err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);

	if (err < 0)

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

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

			  struct netlink_ext_ack *extack)

{

	struct ip_tunnel_parm p;

	__u32 fwmark = 0;

	int err;



	err = ipgre_newlink_encap_setup(dev, data);

	if (err)

		return err;



	err = erspan_netlink_parms(dev, data, tb, &p, &fwmark);

	if (err)

		return err;

	return ip_tunnel_newlink(dev, tb, &p, fwmark);

}
@@ -1304,17 +1349,13 @@ static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[], 
			    struct netlink_ext_ack *extack)

{

	struct ip_tunnel *t = netdev_priv(dev);

	struct ip_tunnel_encap ipencap;

	__u32 fwmark = t->fwmark;

	struct ip_tunnel_parm p;

	int err;



	if (ipgre_netlink_encap_parms(data, &ipencap)) {

		err = ip_tunnel_encap_setup(t, &ipencap);



		if (err < 0)

	err = ipgre_newlink_encap_setup(dev, data);

	if (err)

		return err;

	}



	err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);

	if (err < 0)
@@ -1327,12 +1368,38 @@ static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[], 
	t->parms.i_flags = p.i_flags;

	t->parms.o_flags = p.o_flags;



	if (strcmp(dev->rtnl_link_ops->kind, "erspan"))

	ipgre_link_update(dev, !tb[IFLA_MTU]);



	return 0;

}



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

			     struct nlattr *data[],

			     struct netlink_ext_ack *extack)

{

	struct ip_tunnel *t = netdev_priv(dev);

	__u32 fwmark = t->fwmark;

	struct ip_tunnel_parm p;

	int err;



	err = ipgre_newlink_encap_setup(dev, data);

	if (err)

		return err;



	err = erspan_netlink_parms(dev, data, tb, &p, &fwmark);

	if (err < 0)

		return err;



	err = ip_tunnel_changelink(dev, tb, &p, fwmark);

	if (err < 0)

		return err;



	t->parms.i_flags = p.i_flags;

	t->parms.o_flags = p.o_flags;



	return 0;

}



static size_t ipgre_get_size(const struct net_device *dev)

{

	return
@@ -1519,8 +1586,8 @@ static struct rtnl_link_ops erspan_link_ops __read_mostly = { 
	.priv_size	= sizeof(struct ip_tunnel),

	.setup		= erspan_setup,

	.validate	= erspan_validate,

	.newlink	= ipgre_newlink,

	.changelink	= ipgre_changelink,

	.newlink	= erspan_newlink,

	.changelink	= erspan_changelink,

	.dellink	= ip_tunnel_dellink,

	.get_size	= ipgre_get_size,

	.fill_info	= ipgre_fill_info,

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