genetlink: make netns aware

This makes generic netlink network namespace aware. No
generic netlink families except for the controller family
are made namespace aware, they need to be checked one by
one and then set the family->netnsok member to true.

A new function genlmsg_multicast_netns() is introduced to
allow sending a multicast message in a given namespace,
for example when it applies to an object that lives in
that namespace, a new function genlmsg_multicast_allns()
to send a message to all network namespaces (for objects
that do not have an associated netns).

The function genlmsg_multicast() is changed to multicast
the message in just init_net, which is currently correct
for all generic netlink families since they only work in
init_net right now. Some will later want to work in all
net namespaces because they do not care about the netns
at all -- those will have to be converted to use one of
the new functions genlmsg_multicast_allns() or
genlmsg_multicast_netns() whenever they are made netns
aware in some way.

After this patch families can easily decide whether or
not they should be available in all net namespaces. Many
genl families us it for objects not related to networking
and should therefore be available in all namespaces, but
that will have to be done on a per family basis.

Note that this doesn't touch on the checkpoint/restart
problem where network namespaces could be used, genl
families and multicast groups are numbered globally and
I see no easy way of changing that, especially since it
must be possible to multicast to all network namespaces
for those families that do not care about netns.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 5 deletions

diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 888adbcca30c..ea8384d3caa7 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -108,7 +108,7 @@ static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
 /*
  * Send taskstats data in @skb to listener with nl_pid @pid
  */
-static int send_reply(struct sk_buff *skb, pid_t pid)
+static int send_reply(struct sk_buff *skb, struct genl_info *info)
 {
         struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
         void *reply = genlmsg_data(genlhdr);
@@ -120,7 +120,7 @@ static int send_reply(struct sk_buff *skb, pid_t pid)
                 return rc;
         }
 
-        return genlmsg_unicast(skb, pid);
+        return genlmsg_reply(skb, info);
 }
 
 /*
@@ -150,7 +150,7 @@ static void send_cpu_listeners(struct sk_buff *skb,
                         if (!skb_next)
                                 break;
                 }
-                rc = genlmsg_unicast(skb_cur, s->pid);
+                rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
                 if (rc == -ECONNREFUSED) {
                         s->valid = 0;
                         delcount++;
@@ -418,7 +418,7 @@ static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
                 goto err;
         }
 
-        rc = send_reply(rep_skb, info->snd_pid);
+        rc = send_reply(rep_skb, info);
 
 err:
         fput_light(file, fput_needed);
@@ -487,7 +487,7 @@ free_return_rc:
         } else
                 goto err;
 
-        return send_reply(rep_skb, info->snd_pid);
+        return send_reply(rep_skb, info);
 err:
         nlmsg_free(rep_skb);
         return rc;