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Commit b80d0b93 authored by William Tu's avatar William Tu Committed by David S. Miller
Browse files

net: ip6_gre: fix tunnel metadata device sharing. 



Currently ip6gre and ip6erspan share single metadata mode device,
using 'collect_md_tun'.  Thus, when doing:
  ip link add dev ip6gre11 type ip6gretap external
  ip link add dev ip6erspan12 type ip6erspan external
  RTNETLINK answers: File exists
simply fails due to the 2nd tries to create the same collect_md_tun.

The patch fixes it by adding a separate collect md tunnel device
for the ip6erspan, 'collect_md_tun_erspan'.  As a result, a couple
of places need to refactor/split up in order to distinguish ip6gre
and ip6erspan.

First, move the collect_md check at ip6gre_tunnel_{unlink,link} and
create separate function {ip6gre,ip6ersapn}_tunnel_{link_md,unlink_md}.
Then before link/unlink, make sure the link_md/unlink_md is called.
Finally, a separate ndo_uninit is created for ip6erspan.  Tested it
using the samples/bpf/test_tunnel_bpf.sh.

Fixes: ef7baf5e ("ip6_gre: add ip6 erspan collect_md mode")
Signed-off-by: default avatarWilliam Tu <u9012063@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d775f26b

net/ipv6/ip6_gre.c

+79 −22
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ struct ip6gre_net { 
	struct ip6_tnl __rcu *tunnels[4][IP6_GRE_HASH_SIZE];



	struct ip6_tnl __rcu *collect_md_tun;

	struct ip6_tnl __rcu *collect_md_tun_erspan;

	struct net_device *fb_tunnel_dev;

};
@@ -233,7 +234,12 @@ static struct ip6_tnl *ip6gre_tunnel_lookup(struct net_device *dev, 
	if (cand)

		return cand;



	if (gre_proto == htons(ETH_P_ERSPAN) ||

	    gre_proto == htons(ETH_P_ERSPAN2))

		t = rcu_dereference(ign->collect_md_tun_erspan);

	else

		t = rcu_dereference(ign->collect_md_tun);



	if (t && t->dev->flags & IFF_UP)

		return t;
@@ -262,6 +268,31 @@ static struct ip6_tnl __rcu **__ip6gre_bucket(struct ip6gre_net *ign, 
	return &ign->tunnels[prio][h];

}



static void ip6gre_tunnel_link_md(struct ip6gre_net *ign, struct ip6_tnl *t)

{

	if (t->parms.collect_md)

		rcu_assign_pointer(ign->collect_md_tun, t);

}



static void ip6erspan_tunnel_link_md(struct ip6gre_net *ign, struct ip6_tnl *t)

{

	if (t->parms.collect_md)

		rcu_assign_pointer(ign->collect_md_tun_erspan, t);

}



static void ip6gre_tunnel_unlink_md(struct ip6gre_net *ign, struct ip6_tnl *t)

{

	if (t->parms.collect_md)

		rcu_assign_pointer(ign->collect_md_tun, NULL);

}



static void ip6erspan_tunnel_unlink_md(struct ip6gre_net *ign,

				       struct ip6_tnl *t)

{

	if (t->parms.collect_md)

		rcu_assign_pointer(ign->collect_md_tun_erspan, NULL);

}



static inline struct ip6_tnl __rcu **ip6gre_bucket(struct ip6gre_net *ign,

		const struct ip6_tnl *t)

{
@@ -272,9 +303,6 @@ static void ip6gre_tunnel_link(struct ip6gre_net *ign, struct ip6_tnl *t) 
{

	struct ip6_tnl __rcu **tp = ip6gre_bucket(ign, t);



	if (t->parms.collect_md)

		rcu_assign_pointer(ign->collect_md_tun, t);



	rcu_assign_pointer(t->next, rtnl_dereference(*tp));

	rcu_assign_pointer(*tp, t);

}
@@ -284,9 +312,6 @@ static void ip6gre_tunnel_unlink(struct ip6gre_net *ign, struct ip6_tnl *t) 
	struct ip6_tnl __rcu **tp;

	struct ip6_tnl *iter;



	if (t->parms.collect_md)

		rcu_assign_pointer(ign->collect_md_tun, NULL);



	for (tp = ip6gre_bucket(ign, t);

	     (iter = rtnl_dereference(*tp)) != NULL;

	     tp = &iter->next) {
@@ -375,11 +400,23 @@ static struct ip6_tnl *ip6gre_tunnel_locate(struct net *net, 
	return NULL;

}



static void ip6erspan_tunnel_uninit(struct net_device *dev)

{

	struct ip6_tnl *t = netdev_priv(dev);

	struct ip6gre_net *ign = net_generic(t->net, ip6gre_net_id);



	ip6erspan_tunnel_unlink_md(ign, t);

	ip6gre_tunnel_unlink(ign, t);

	dst_cache_reset(&t->dst_cache);

	dev_put(dev);

}



static void ip6gre_tunnel_uninit(struct net_device *dev)

{

	struct ip6_tnl *t = netdev_priv(dev);

	struct ip6gre_net *ign = net_generic(t->net, ip6gre_net_id);



	ip6gre_tunnel_unlink_md(ign, t);

	ip6gre_tunnel_unlink(ign, t);

	dst_cache_reset(&t->dst_cache);

	dev_put(dev);
@@ -1806,7 +1843,7 @@ static int ip6erspan_tap_init(struct net_device *dev) 


static const struct net_device_ops ip6erspan_netdev_ops = {

	.ndo_init =		ip6erspan_tap_init,

	.ndo_uninit =		ip6gre_tunnel_uninit,

	.ndo_uninit =		ip6erspan_tunnel_uninit,

	.ndo_start_xmit =	ip6erspan_tunnel_xmit,

	.ndo_set_mac_address =	eth_mac_addr,

	.ndo_validate_addr =	eth_validate_addr,
@@ -1875,8 +1912,6 @@ static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev, 
				 struct netlink_ext_ack *extack)

{

	struct ip6_tnl *nt;

	struct net *net = dev_net(dev);

	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);

	struct ip_tunnel_encap ipencap;

	int err;
@@ -1889,16 +1924,6 @@ static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev, 
			return err;

	}



	ip6gre_netlink_parms(data, &nt->parms);



	if (nt->parms.collect_md) {

		if (rtnl_dereference(ign->collect_md_tun))

			return -EEXIST;

	} else {

		if (ip6gre_tunnel_find(net, &nt->parms, dev->type))

			return -EEXIST;

	}



	if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])

		eth_hw_addr_random(dev);
@@ -1922,12 +1947,26 @@ static int ip6gre_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);

	struct ip6gre_net *ign;

	int err;



	ip6gre_netlink_parms(data, &nt->parms);

	ign = net_generic(net, ip6gre_net_id);



	if (nt->parms.collect_md) {

		if (rtnl_dereference(ign->collect_md_tun))

			return -EEXIST;

	} else {

		if (ip6gre_tunnel_find(net, &nt->parms, dev->type))

			return -EEXIST;

	}



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

	if (!err) {

		ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);

		ip6gre_tunnel_link_md(ign, nt);

		ip6gre_tunnel_link(net_generic(net, ip6gre_net_id), nt);

	}

	return err;
@@ -1979,8 +2018,10 @@ static int ip6gre_changelink(struct net_device *dev, struct nlattr *tb[], 
	if (IS_ERR(t))

		return PTR_ERR(t);



	ip6gre_tunnel_unlink_md(ign, t);

	ip6gre_tunnel_unlink(ign, t);

	ip6gre_tnl_change(t, &p, !tb[IFLA_MTU]);

	ip6gre_tunnel_link_md(ign, t);

	ip6gre_tunnel_link(ign, t);

	return 0;

}
@@ -2134,12 +2175,26 @@ 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);

	struct ip6gre_net *ign;

	int err;



	ip6gre_netlink_parms(data, &nt->parms);

	ign = net_generic(net, ip6gre_net_id);



	if (nt->parms.collect_md) {

		if (rtnl_dereference(ign->collect_md_tun_erspan))

			return -EEXIST;

	} else {

		if (ip6gre_tunnel_find(net, &nt->parms, dev->type))

			return -EEXIST;

	}



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

	if (!err) {

		ip6erspan_tnl_link_config(nt, !tb[IFLA_MTU]);

		ip6erspan_tunnel_link_md(ign, nt);

		ip6gre_tunnel_link(net_generic(net, ip6gre_net_id), nt);

	}

	return err;
@@ -2171,8 +2226,10 @@ static int ip6erspan_changelink(struct net_device *dev, struct nlattr *tb[], 
	if (IS_ERR(t))

		return PTR_ERR(t);



	ip6gre_tunnel_unlink_md(ign, t);

	ip6gre_tunnel_unlink(ign, t);

	ip6erspan_tnl_change(t, &p, !tb[IFLA_MTU]);

	ip6erspan_tunnel_link_md(ign, t);

	ip6gre_tunnel_link(ign, t);

	return 0;

}