Commit 971b4ad8 authored by Jiri Pirko's avatar Jiri Pirko Committed by Paolo Abeni
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genetlink: introduce helpers to do filtered multicast 



Currently it is possible for netlink kernel user to pass custom
filter function to broadcast send function netlink_broadcast_filtered().
However, this is not exposed to multicast send and to generic
netlink users.

Extend the api and introduce a netlink helper nlmsg_multicast_filtered()
and a generic netlink helper genlmsg_multicast_netns_filtered()
to allow generic netlink families to specify filter function
while sending multicast messages.

Signed-off-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 403863e9

include/net/genetlink.h

+31 −4
Original line number Diff line number Diff line
@@ -449,22 +449,49 @@ static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 
}



/**

 * genlmsg_multicast_netns - multicast a netlink message to a specific netns

 * genlmsg_multicast_netns_filtered - multicast a netlink message

 *				      to a specific netns with filter

 *				      function

 * @family: the generic netlink family

 * @net: the net namespace

 * @skb: netlink message as socket buffer

 * @portid: own netlink portid to avoid sending to yourself

 * @group: offset of multicast group in groups array

 * @flags: allocation flags

 * @filter: filter function

 * @filter_data: filter function private data

 *

 * Return: 0 on success, negative error code for failure.

 */

static inline int genlmsg_multicast_netns(const struct genl_family *family,

static inline int

genlmsg_multicast_netns_filtered(const struct genl_family *family,

				 struct net *net, struct sk_buff *skb,

					  u32 portid, unsigned int group, gfp_t flags)

				 u32 portid, unsigned int group, gfp_t flags,

				 netlink_filter_fn filter,

				 void *filter_data)

{

	if (WARN_ON_ONCE(group >= family->n_mcgrps))

		return -EINVAL;

	group = family->mcgrp_offset + group;

	return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);

	return nlmsg_multicast_filtered(net->genl_sock, skb, portid, group,

					flags, filter, filter_data);

}



/**

 * genlmsg_multicast_netns - multicast a netlink message to a specific netns

 * @family: the generic netlink family

 * @net: the net namespace

 * @skb: netlink message as socket buffer

 * @portid: own netlink portid to avoid sending to yourself

 * @group: offset of multicast group in groups array

 * @flags: allocation flags

 */

static inline int genlmsg_multicast_netns(const struct genl_family *family,

					  struct net *net, struct sk_buff *skb,

					  u32 portid, unsigned int group, gfp_t flags)

{

	return genlmsg_multicast_netns_filtered(family, net, skb, portid,

						group, flags, NULL, NULL);

}



/**

include/net/netlink.h

+27 −4
Original line number Diff line number Diff line
@@ -1087,27 +1087,50 @@ static inline void nlmsg_free(struct sk_buff *skb) 
}



/**

 * nlmsg_multicast - multicast a netlink message

 * nlmsg_multicast_filtered - multicast a netlink message with filter function

 * @sk: netlink socket to spread messages to

 * @skb: netlink message as socket buffer

 * @portid: own netlink portid to avoid sending to yourself

 * @group: multicast group id

 * @flags: allocation flags

 * @filter: filter function

 * @filter_data: filter function private data

 *

 * Return: 0 on success, negative error code for failure.

 */

static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,

				  u32 portid, unsigned int group, gfp_t flags)

static inline int nlmsg_multicast_filtered(struct sock *sk, struct sk_buff *skb,

					   u32 portid, unsigned int group,

					   gfp_t flags,

					   netlink_filter_fn filter,

					   void *filter_data)

{

	int err;



	NETLINK_CB(skb).dst_group = group;



	err = netlink_broadcast(sk, skb, portid, group, flags);

	err = netlink_broadcast_filtered(sk, skb, portid, group, flags,

					 filter, filter_data);

	if (err > 0)

		err = 0;



	return err;

}



/**

 * nlmsg_multicast - multicast a netlink message

 * @sk: netlink socket to spread messages to

 * @skb: netlink message as socket buffer

 * @portid: own netlink portid to avoid sending to yourself

 * @group: multicast group id

 * @flags: allocation flags

 */

static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,

				  u32 portid, unsigned int group, gfp_t flags)

{

	return nlmsg_multicast_filtered(sk, skb, portid, group, flags,

					NULL, NULL);

}



/**

 * nlmsg_unicast - unicast a netlink message

 * @sk: netlink socket to spread message to