Commit 745041e2 authored by Robert Shearman's avatar Robert Shearman Committed by David S. Miller
Browse files

lwtunnel: autoload of lwt modules 



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: default avatarRobert Shearman <rshearma@brocade.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e817af27

include/net/lwtunnel.h

+3 −1
Original line number Diff line number Diff line
@@ -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 */

net/core/lwtunnel.c

+37 −0
Original line number Diff line number Diff line
@@ -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();

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