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lwtunnel: autoload of lwt modules

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The lwt implementations using net devices can autoload using the
existing mechanism using IFLA_INFO_KIND. However, there's no mechanism
that lwt modules not using net devices can use.

Therefore, add the ability to autoload modules registering lwt
operations for lwt implementations not using a net device so that
users don't have to manually load the modules.

Only users with the CAP_NET_ADMIN capability can cause modules to be
loaded, which is ensured by rtnetlink_rcv_msg rejecting non-RTM_GETxxx
messages for users without this capability, and by
lwtunnel_build_state not being called in response to RTM_GETxxx
messages.

Signed-off-by: Robert Shearman <rshearma@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Robert Shearman 2016-02-19 09:43:16 +00:00 committed by David S. Miller
parent e817af27e0
commit 745041e2aa
2 changed files with 40 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
include/net/lwtunnel.h
View file

@ -170,6 +170,8 @@ static inline int lwtunnel_input(struct sk_buff *skb)
return -EOPNOTSUPP;
}
#endif
#endif /* CONFIG_LWTUNNEL */
#define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
#endif /* __NET_LWTUNNEL_H */

37
net/core/lwtunnel.c
View file

@ -27,6 +27,31 @@
#include <net/rtnetlink.h>
#include <net/ip6_fib.h>
#ifdef CONFIG_MODULES
static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type)
{
/* Only lwt encaps implemented without using an interface for
* the encap need to return a string here.
*/
switch (encap_type) {
case LWTUNNEL_ENCAP_MPLS:
return "MPLS";
case LWTUNNEL_ENCAP_ILA:
return "ILA";
case LWTUNNEL_ENCAP_IP6:
case LWTUNNEL_ENCAP_IP:
case LWTUNNEL_ENCAP_NONE:
case __LWTUNNEL_ENCAP_MAX:
/* should not have got here */
WARN_ON(1);
break;
}
return NULL;
}
#endif /* CONFIG_MODULES */
struct lwtunnel_state *lwtunnel_state_alloc(int encap_len)
{
struct lwtunnel_state *lws;
@ -85,6 +110,18 @@ int lwtunnel_build_state(struct net_device *dev, u16 encap_type,
ret = -EOPNOTSUPP;
rcu_read_lock();
ops = rcu_dereference(lwtun_encaps[encap_type]);
#ifdef CONFIG_MODULES
if (!ops) {
const char *encap_type_str = lwtunnel_encap_str(encap_type);
if (encap_type_str) {
rcu_read_unlock();
request_module("rtnl-lwt-%s", encap_type_str);
rcu_read_lock();
ops = rcu_dereference(lwtun_encaps[encap_type]);
}
}
#endif
if (likely(ops && ops->build_state))
ret = ops->build_state(dev, encap, family, cfg, lws);
rcu_read_unlock();