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net: ip6_gre: fix tunnel metadata device sharing.
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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: ef7baf5 ("ip6_gre: add ip6 erspan collect_md mode")
Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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William Tu authored and David S. Miller committed May 20, 2018
1 parent d775f26 commit b80d0b9
Showing 1 changed file with 79 additions and 22 deletions.
101 changes: 79 additions & 22 deletions net/ipv6/ip6_gre.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
};

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

t = rcu_dereference(ign->collect_md_tun);
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;

Expand Down Expand Up @@ -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)
{
Expand All @@ -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);
}
Expand All @@ -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) {
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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;

Expand All @@ -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);

Expand All @@ -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;
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
}
Expand Down

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