/**
* genl_register_mc_group - register a multicast group
*
* Registers the specified multicast group and notifies userspace
* about the new group.
*
* Returns 0 on success or a negative error code.
*
* @family: The generic netlink family the group shall be registered for.
* @grp: The group to register, must have a name.
*/
int genl_register_mc_group(struct genl_family *family,
struct genl_multicast_group *grp)
{
int id;
unsigned long *new_groups;
int err = 0;
BUG_ON(grp->name[0] == '\0');
BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);
genl_lock_all();
/* special-case our own group */
if (grp == ¬ify_grp)
id = GENL_ID_CTRL;
else
id = find_first_zero_bit(mc_groups,
mc_groups_longs * BITS_PER_LONG);
if (id >= mc_groups_longs * BITS_PER_LONG) {
size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
if (mc_groups == &mc_group_start) {
new_groups = kzalloc(nlen, GFP_KERNEL);
if (!new_groups) {
err = -ENOMEM;
goto out;
}
mc_groups = new_groups;
*mc_groups = mc_group_start;
} else {
new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
if (!new_groups) {
err = -ENOMEM;
goto out;
}
mc_groups = new_groups;
mc_groups[mc_groups_longs] = 0;
}
mc_groups_longs++;
}
if (family->netnsok) {
struct net *net;
netlink_table_grab();
rcu_read_lock();
for_each_net_rcu(net) {
err = __netlink_change_ngroups(net->genl_sock,
mc_groups_longs * BITS_PER_LONG);
if (err) {
/*
* No need to roll back, can only fail if
* memory allocation fails and then the
* number of _possible_ groups has been
* increased on some sockets which is ok.
*/
rcu_read_unlock();
netlink_table_ungrab();
goto out;
}
}
rcu_read_unlock();
netlink_table_ungrab();
} else {
static int genl_validate_assign_mc_groups(struct genl_family *family)
{
int first_id;
int n_groups = family->n_mcgrps;
int err = 0, i;
bool groups_allocated = false;
if (!n_groups)
return 0;
for (i = 0; i < n_groups; i++) {
const struct genl_multicast_group *grp = &family->mcgrps[i];
if (WARN_ON(grp->name[0] == '\0'))
return -EINVAL;
if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
return -EINVAL;
}
/* special-case our own group and hacks */
if (family == &genl_ctrl) {
first_id = GENL_ID_CTRL;
BUG_ON(n_groups != 1);
} else if (strcmp(family->name, "NET_DM") == 0) {
first_id = 1;
BUG_ON(n_groups != 1);
} else if (family->id == GENL_ID_VFS_DQUOT) {
first_id = GENL_ID_VFS_DQUOT;
BUG_ON(n_groups != 1);
} else if (family->id == GENL_ID_PMCRAID) {
first_id = GENL_ID_PMCRAID;
BUG_ON(n_groups != 1);
} else {
groups_allocated = true;
err = genl_allocate_reserve_groups(n_groups, &first_id);
if (err)
return err;
}
family->mcgrp_offset = first_id;
/* if still initializing, can't and don't need to to realloc bitmaps */
if (!init_net.genl_sock)
return 0;
if (family->netnsok) {
struct net *net;
netlink_table_grab();
rcu_read_lock();
for_each_net_rcu(net) {
err = __netlink_change_ngroups(net->genl_sock,
mc_groups_longs * BITS_PER_LONG);
if (err) {
/*
* No need to roll back, can only fail if
* memory allocation fails and then the
* number of _possible_ groups has been
* increased on some sockets which is ok.
*/
break;
}
}
rcu_read_unlock();
netlink_table_ungrab();
} else {
