@@ -51,6 +51,9 @@ struct genl_info;
* @split_ops: the split do/dump form of operation definition
* @n_split_ops: number of entries in @split_ops, not that with split do/dump
* ops the number of entries is not the same as number of commands
+ * @sock_priv_size: the size of per-socket private memory
+ * @sock_priv_init: the per-socket private memory initializer
+ * @sock_priv_destroy: the per-socket private memory destructor
*
* Attribute policies (the combination of @policy and @maxattr fields)
* can be attached at the family level or at the operation level.
@@ -84,11 +87,17 @@ struct genl_family {
const struct genl_multicast_group *mcgrps;
struct module *module;
+ size_t sock_priv_size;
+ void (*sock_priv_init)(void *priv);
+ void (*sock_priv_destroy)(void *priv);
+
/* private: internal use only */
/* protocol family identifier */
int id;
/* starting number of multicast group IDs in this family */
unsigned int mcgrp_offset;
+ /* list of per-socket privs */
+ struct xarray *sock_privs;
};
/**
@@ -298,6 +307,8 @@ static inline bool genl_info_is_ntf(const struct genl_info *info)
return !info->nlhdr;
}
+void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk);
+void *genl_sk_priv_get(struct genl_family *family, struct sock *sk);
int genl_register_family(struct genl_family *family);
int genl_unregister_family(const struct genl_family *family);
void genl_notify(const struct genl_family *family, struct sk_buff *skb,
@@ -631,6 +631,138 @@ static int genl_validate_ops(const struct genl_family *family)
return 0;
}
+static void *genl_sk_priv_alloc(struct genl_family *family)
+{
+ void *priv;
+
+ priv = kzalloc(family->sock_priv_size, GFP_KERNEL);
+ if (!priv)
+ return ERR_PTR(-ENOMEM);
+
+ if (family->sock_priv_init)
+ family->sock_priv_init(priv);
+
+ return priv;
+}
+
+static void genl_sk_priv_free(const struct genl_family *family, void *priv)
+{
+ if (family->sock_priv_destroy)
+ family->sock_priv_destroy(priv);
+ kfree(priv);
+}
+
+static int genl_sk_privs_alloc(struct genl_family *family)
+{
+ if (!family->sock_priv_size)
+ return 0;
+
+ family->sock_privs = kzalloc(sizeof(*family->sock_privs), GFP_KERNEL);
+ if (!family->sock_privs)
+ return -ENOMEM;
+ xa_init(family->sock_privs);
+ return 0;
+}
+
+static void genl_sk_privs_free(const struct genl_family *family)
+{
+ unsigned long id;
+ void *priv;
+
+ if (!family->sock_priv_size)
+ return;
+
+ xa_for_each(family->sock_privs, id, priv)
+ genl_sk_priv_free(family, priv);
+
+ xa_destroy(family->sock_privs);
+ kfree(family->sock_privs);
+}
+
+static void genl_sk_priv_free_by_sock(struct genl_family *family,
+ struct sock *sk)
+{
+ void *priv;
+
+ if (!family->sock_priv_size)
+ return;
+ priv = xa_erase(family->sock_privs, (unsigned long) sk);
+ if (!priv)
+ return;
+ genl_sk_priv_free(family, priv);
+}
+
+static void genl_release(struct sock *sk, unsigned long *groups)
+{
+ struct genl_family *family;
+ unsigned int id;
+
+ down_read(&cb_lock);
+
+ idr_for_each_entry(&genl_fam_idr, family, id)
+ genl_sk_priv_free_by_sock(family, sk);
+
+ up_read(&cb_lock);
+}
+
+/**
+ * __genl_sk_priv_get - Get family private pointer for socket, if exists
+ *
+ * @family: family
+ * @sk: socket
+ *
+ * Lookup a private memory for a Generic netlink family and specified socket.
+ *
+ * Caller should make sure this is called in RCU read locked section.
+ *
+ * Return: valid pointer on success, otherwise negative error value
+ * encoded by ERR_PTR(), NULL in case priv does not exist.
+ */
+void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk)
+{
+ if (WARN_ON_ONCE(!family->sock_privs))
+ return ERR_PTR(-EINVAL);
+ return xa_load(family->sock_privs, (unsigned long) sk);
+}
+
+/**
+ * genl_sk_priv_get - Get family private pointer for socket
+ *
+ * @family: family
+ * @sk: socket
+ *
+ * Lookup a private memory for a Generic netlink family and specified socket.
+ * Allocate the private memory in case it was not already done.
+ *
+ * Return: valid pointer on success, otherwise negative error value
+ * encoded by ERR_PTR().
+ */
+void *genl_sk_priv_get(struct genl_family *family, struct sock *sk)
+{
+ void *priv, *old_priv;
+
+ priv = __genl_sk_priv_get(family, sk);
+ if (priv)
+ return priv;
+
+ /* priv for the family does not exist so far, create it. */
+
+ priv = genl_sk_priv_alloc(family);
+ if (IS_ERR(priv))
+ return ERR_CAST(priv);
+
+ old_priv = xa_cmpxchg(family->sock_privs, (unsigned long) sk, NULL,
+ priv, GFP_KERNEL);
+ if (old_priv) {
+ genl_sk_priv_free(family, priv);
+ if (xa_is_err(old_priv))
+ return ERR_PTR(xa_err(old_priv));
+ /* Race happened, priv for the socket was already inserted. */
+ return old_priv;
+ }
+ return priv;
+}
+
/**
* genl_register_family - register a generic netlink family
* @family: generic netlink family
@@ -659,6 +791,10 @@ int genl_register_family(struct genl_family *family)
goto errout_locked;
}
+ err = genl_sk_privs_alloc(family);
+ if (err)
+ goto errout_locked;
+
/*
* Sadly, a few cases need to be special-cased
* due to them having previously abused the API
@@ -679,7 +815,7 @@ int genl_register_family(struct genl_family *family)
start, end + 1, GFP_KERNEL);
if (family->id < 0) {
err = family->id;
- goto errout_locked;
+ goto errout_sk_privs_free;
}
err = genl_validate_assign_mc_groups(family);
@@ -698,6 +834,8 @@ int genl_register_family(struct genl_family *family)
errout_remove:
idr_remove(&genl_fam_idr, family->id);
+errout_sk_privs_free:
+ genl_sk_privs_free(family);
errout_locked:
genl_unlock_all();
return err;
@@ -728,6 +866,9 @@ int genl_unregister_family(const struct genl_family *family)
up_write(&cb_lock);
wait_event(genl_sk_destructing_waitq,
atomic_read(&genl_sk_destructing_cnt) == 0);
+
+ genl_sk_privs_free(family);
+
genl_unlock();
genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
@@ -1708,6 +1849,7 @@ static int __net_init genl_pernet_init(struct net *net)
.input = genl_rcv,
.flags = NL_CFG_F_NONROOT_RECV,
.bind = genl_bind,
+ .release = genl_release,
};
/* we'll bump the group number right afterwards */