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-rw-r--r--include/net/genetlink.h5
-rw-r--r--net/netlink/genetlink.c59
2 files changed, 64 insertions, 0 deletions
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index 38620da4aa7a..3ed31e5a445b 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -31,6 +31,9 @@ struct genl_info;
* do additional, common, filtering and return an error
* @post_doit: called after an operation's doit callback, it may
* undo operations done by pre_doit, for example release locks
+ * @mcast_bind: a socket bound to the given multicast group (which
+ * is given as the offset into the groups array)
+ * @mcast_unbind: a socket was unbound from the given multicast group
* @attrbuf: buffer to store parsed attributes
* @family_list: family list
* @mcgrps: multicast groups used by this family (private)
@@ -53,6 +56,8 @@ struct genl_family {
void (*post_doit)(const struct genl_ops *ops,
struct sk_buff *skb,
struct genl_info *info);
+ int (*mcast_bind)(int group);
+ void (*mcast_unbind)(int group);
struct nlattr ** attrbuf; /* private */
const struct genl_ops * ops; /* private */
const struct genl_multicast_group *mcgrps; /* private */
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 76393f2f4b22..05bf40bbd189 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -983,11 +983,70 @@ static struct genl_multicast_group genl_ctrl_groups[] = {
{ .name = "notify", },
};
+static int genl_bind(int group)
+{
+ int i, err;
+ bool found = false;
+
+ down_read(&cb_lock);
+ for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
+ struct genl_family *f;
+
+ list_for_each_entry(f, genl_family_chain(i), family_list) {
+ if (group >= f->mcgrp_offset &&
+ group < f->mcgrp_offset + f->n_mcgrps) {
+ int fam_grp = group - f->mcgrp_offset;
+
+ if (f->mcast_bind)
+ err = f->mcast_bind(fam_grp);
+ else
+ err = 0;
+ found = true;
+ break;
+ }
+ }
+ }
+ up_read(&cb_lock);
+
+ if (WARN_ON(!found))
+ err = 0;
+
+ return err;
+}
+
+static void genl_unbind(int group)
+{
+ int i;
+ bool found = false;
+
+ down_read(&cb_lock);
+ for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
+ struct genl_family *f;
+
+ list_for_each_entry(f, genl_family_chain(i), family_list) {
+ if (group >= f->mcgrp_offset &&
+ group < f->mcgrp_offset + f->n_mcgrps) {
+ int fam_grp = group - f->mcgrp_offset;
+
+ if (f->mcast_unbind)
+ f->mcast_unbind(fam_grp);
+ found = true;
+ break;
+ }
+ }
+ }
+ up_read(&cb_lock);
+
+ WARN_ON(!found);
+}
+
static int __net_init genl_pernet_init(struct net *net)
{
struct netlink_kernel_cfg cfg = {
.input = genl_rcv,
.flags = NL_CFG_F_NONROOT_RECV,
+ .bind = genl_bind,
+ .unbind = genl_unbind,
};
/* we'll bump the group number right afterwards */