genetlink: make multicast groups const, prevent abuse

Register generic netlink multicast groups as an array with
the family and give them contiguous group IDs. Then instead
of passing the global group ID to the various functions that
send messages, pass the ID relative to the family - for most
families that's just 0 because the only have one group.

This avoids the list_head and ID in each group, adding a new
field for the mcast group ID offset to the family.

At the same time, this allows us to prevent abusing groups
again like the quota and dropmon code did, since we can now
check that a family only uses a group it owns.

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

1 files changed, 7 insertions, 15 deletions

diff --git a/net/ieee802154/nl-mac.c b/net/ieee802154/nl-mac.c
index 28d493032132..ba5c1e002f37 100644
--- a/net/ieee802154/nl-mac.c
+++ b/net/ieee802154/nl-mac.c
@@ -39,14 +39,6 @@
 
 #include "ieee802154.h"
 
-struct genl_multicast_group ieee802154_coord_mcgrp = {
-        .name           = IEEE802154_MCAST_COORD_NAME,
-};
-
-struct genl_multicast_group ieee802154_beacon_mcgrp = {
-        .name           = IEEE802154_MCAST_BEACON_NAME,
-};
-
 int ieee802154_nl_assoc_indic(struct net_device *dev,
                 struct ieee802154_addr *addr, u8 cap)
 {
@@ -72,7 +64,7 @@ int ieee802154_nl_assoc_indic(struct net_device *dev,
             nla_put_u8(msg, IEEE802154_ATTR_CAPABILITY, cap))
                 goto nla_put_failure;
 
-        return ieee802154_nl_mcast(msg, ieee802154_coord_mcgrp.id);
+        return ieee802154_nl_mcast(msg, IEEE802154_COORD_MCGRP);
 
 nla_put_failure:
         nlmsg_free(msg);
@@ -98,7 +90,7 @@ int ieee802154_nl_assoc_confirm(struct net_device *dev, u16 short_addr,
             nla_put_u16(msg, IEEE802154_ATTR_SHORT_ADDR, short_addr) ||
             nla_put_u8(msg, IEEE802154_ATTR_STATUS, status))
                 goto nla_put_failure;
-        return ieee802154_nl_mcast(msg, ieee802154_coord_mcgrp.id);
+        return ieee802154_nl_mcast(msg, IEEE802154_COORD_MCGRP);
 
 nla_put_failure:
         nlmsg_free(msg);
@@ -133,7 +125,7 @@ int ieee802154_nl_disassoc_indic(struct net_device *dev,
         }
         if (nla_put_u8(msg, IEEE802154_ATTR_REASON, reason))
                 goto nla_put_failure;
-        return ieee802154_nl_mcast(msg, ieee802154_coord_mcgrp.id);
+        return ieee802154_nl_mcast(msg, IEEE802154_COORD_MCGRP);
 
 nla_put_failure:
         nlmsg_free(msg);
@@ -157,7 +149,7 @@ int ieee802154_nl_disassoc_confirm(struct net_device *dev, u8 status)
                     dev->dev_addr) ||
             nla_put_u8(msg, IEEE802154_ATTR_STATUS, status))
                 goto nla_put_failure;
-        return ieee802154_nl_mcast(msg, ieee802154_coord_mcgrp.id);
+        return ieee802154_nl_mcast(msg, IEEE802154_COORD_MCGRP);
 
 nla_put_failure:
         nlmsg_free(msg);
@@ -183,7 +175,7 @@ int ieee802154_nl_beacon_indic(struct net_device *dev,
             nla_put_u16(msg, IEEE802154_ATTR_COORD_SHORT_ADDR, coord_addr) ||
             nla_put_u16(msg, IEEE802154_ATTR_COORD_PAN_ID, panid))
                 goto nla_put_failure;
-        return ieee802154_nl_mcast(msg, ieee802154_coord_mcgrp.id);
+        return ieee802154_nl_mcast(msg, IEEE802154_COORD_MCGRP);
 
 nla_put_failure:
         nlmsg_free(msg);
@@ -214,7 +206,7 @@ int ieee802154_nl_scan_confirm(struct net_device *dev,
             (edl &&
              nla_put(msg, IEEE802154_ATTR_ED_LIST, 27, edl)))
                 goto nla_put_failure;
-        return ieee802154_nl_mcast(msg, ieee802154_coord_mcgrp.id);
+        return ieee802154_nl_mcast(msg, IEEE802154_COORD_MCGRP);
 
 nla_put_failure:
         nlmsg_free(msg);
@@ -238,7 +230,7 @@ int ieee802154_nl_start_confirm(struct net_device *dev, u8 status)
                     dev->dev_addr) ||
             nla_put_u8(msg, IEEE802154_ATTR_STATUS, status))
                 goto nla_put_failure;
-        return ieee802154_nl_mcast(msg, ieee802154_coord_mcgrp.id);
+        return ieee802154_nl_mcast(msg, IEEE802154_COORD_MCGRP);
 
 nla_put_failure:
         nlmsg_free(msg);