![YOSHIFUJI Hideaki](/assets/img/avatar_default.png)
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
608 lines
13 KiB
C
608 lines
13 KiB
C
/*
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* NETLINK Generic Netlink Family
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*
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* Authors: Jamal Hadi Salim
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* Thomas Graf <tgraf@suug.ch>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/string.h>
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#include <linux/skbuff.h>
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#include <linux/mutex.h>
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#include <net/sock.h>
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#include <net/genetlink.h>
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struct sock *genl_sock = NULL;
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static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
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static void genl_lock(void)
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{
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mutex_lock(&genl_mutex);
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}
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static int genl_trylock(void)
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{
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return !mutex_trylock(&genl_mutex);
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}
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static void genl_unlock(void)
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{
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mutex_unlock(&genl_mutex);
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if (genl_sock && genl_sock->sk_receive_queue.qlen)
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genl_sock->sk_data_ready(genl_sock, 0);
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}
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#define GENL_FAM_TAB_SIZE 16
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#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
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static struct list_head family_ht[GENL_FAM_TAB_SIZE];
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static int genl_ctrl_event(int event, void *data);
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static inline unsigned int genl_family_hash(unsigned int id)
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{
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return id & GENL_FAM_TAB_MASK;
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}
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static inline struct list_head *genl_family_chain(unsigned int id)
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{
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return &family_ht[genl_family_hash(id)];
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}
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static struct genl_family *genl_family_find_byid(unsigned int id)
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{
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struct genl_family *f;
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list_for_each_entry(f, genl_family_chain(id), family_list)
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if (f->id == id)
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return f;
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return NULL;
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}
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static struct genl_family *genl_family_find_byname(char *name)
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{
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struct genl_family *f;
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int i;
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for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
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list_for_each_entry(f, genl_family_chain(i), family_list)
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if (strcmp(f->name, name) == 0)
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return f;
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return NULL;
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}
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static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
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{
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struct genl_ops *ops;
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list_for_each_entry(ops, &family->ops_list, ops_list)
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if (ops->cmd == cmd)
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return ops;
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return NULL;
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}
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/* Of course we are going to have problems once we hit
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* 2^16 alive types, but that can only happen by year 2K
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*/
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static inline u16 genl_generate_id(void)
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{
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static u16 id_gen_idx;
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int overflowed = 0;
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do {
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if (id_gen_idx == 0)
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id_gen_idx = GENL_MIN_ID;
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if (++id_gen_idx > GENL_MAX_ID) {
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if (!overflowed) {
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overflowed = 1;
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id_gen_idx = 0;
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continue;
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} else
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return 0;
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}
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} while (genl_family_find_byid(id_gen_idx));
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return id_gen_idx;
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}
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/**
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* genl_register_ops - register generic netlink operations
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* @family: generic netlink family
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* @ops: operations to be registered
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*
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* Registers the specified operations and assigns them to the specified
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* family. Either a doit or dumpit callback must be specified or the
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* operation will fail. Only one operation structure per command
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* identifier may be registered.
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*
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* See include/net/genetlink.h for more documenation on the operations
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* structure.
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*
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* Returns 0 on success or a negative error code.
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*/
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int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
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{
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int err = -EINVAL;
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if (ops->dumpit == NULL && ops->doit == NULL)
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goto errout;
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if (genl_get_cmd(ops->cmd, family)) {
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err = -EEXIST;
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goto errout;
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}
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if (ops->dumpit)
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ops->flags |= GENL_CMD_CAP_DUMP;
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if (ops->doit)
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ops->flags |= GENL_CMD_CAP_DO;
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if (ops->policy)
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ops->flags |= GENL_CMD_CAP_HASPOL;
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genl_lock();
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list_add_tail(&ops->ops_list, &family->ops_list);
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genl_unlock();
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genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
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err = 0;
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errout:
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return err;
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}
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/**
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* genl_unregister_ops - unregister generic netlink operations
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* @family: generic netlink family
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* @ops: operations to be unregistered
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*
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* Unregisters the specified operations and unassigns them from the
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* specified family. The operation blocks until the current message
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* processing has finished and doesn't start again until the
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* unregister process has finished.
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*
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* Note: It is not necessary to unregister all operations before
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* unregistering the family, unregistering the family will cause
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* all assigned operations to be unregistered automatically.
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*
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* Returns 0 on success or a negative error code.
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*/
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int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
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{
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struct genl_ops *rc;
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genl_lock();
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list_for_each_entry(rc, &family->ops_list, ops_list) {
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if (rc == ops) {
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list_del(&ops->ops_list);
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genl_unlock();
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genl_ctrl_event(CTRL_CMD_DELOPS, ops);
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return 0;
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}
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}
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genl_unlock();
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return -ENOENT;
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}
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/**
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* genl_register_family - register a generic netlink family
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* @family: generic netlink family
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*
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* Registers the specified family after validating it first. Only one
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* family may be registered with the same family name or identifier.
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* The family id may equal GENL_ID_GENERATE causing an unique id to
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* be automatically generated and assigned.
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*
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* Return 0 on success or a negative error code.
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*/
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int genl_register_family(struct genl_family *family)
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{
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int err = -EINVAL;
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if (family->id && family->id < GENL_MIN_ID)
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goto errout;
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if (family->id > GENL_MAX_ID)
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goto errout;
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INIT_LIST_HEAD(&family->ops_list);
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genl_lock();
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if (genl_family_find_byname(family->name)) {
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err = -EEXIST;
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goto errout_locked;
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}
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if (genl_family_find_byid(family->id)) {
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err = -EEXIST;
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goto errout_locked;
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}
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if (family->id == GENL_ID_GENERATE) {
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u16 newid = genl_generate_id();
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if (!newid) {
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err = -ENOMEM;
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goto errout_locked;
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}
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family->id = newid;
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}
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if (family->maxattr) {
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family->attrbuf = kmalloc((family->maxattr+1) *
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sizeof(struct nlattr *), GFP_KERNEL);
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if (family->attrbuf == NULL) {
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err = -ENOMEM;
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goto errout_locked;
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}
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} else
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family->attrbuf = NULL;
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list_add_tail(&family->family_list, genl_family_chain(family->id));
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genl_unlock();
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genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
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return 0;
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errout_locked:
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genl_unlock();
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errout:
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return err;
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}
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/**
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* genl_unregister_family - unregister generic netlink family
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* @family: generic netlink family
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*
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* Unregisters the specified family.
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*
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* Returns 0 on success or a negative error code.
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*/
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int genl_unregister_family(struct genl_family *family)
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{
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struct genl_family *rc;
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genl_lock();
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list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
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if (family->id != rc->id || strcmp(rc->name, family->name))
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continue;
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list_del(&rc->family_list);
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INIT_LIST_HEAD(&family->ops_list);
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genl_unlock();
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kfree(family->attrbuf);
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genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
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return 0;
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}
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genl_unlock();
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return -ENOENT;
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}
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static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
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int *errp)
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{
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struct genl_ops *ops;
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struct genl_family *family;
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struct genl_info info;
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struct genlmsghdr *hdr = nlmsg_data(nlh);
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int hdrlen, err = -EINVAL;
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if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
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goto ignore;
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if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
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goto ignore;
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family = genl_family_find_byid(nlh->nlmsg_type);
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if (family == NULL) {
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err = -ENOENT;
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goto errout;
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}
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hdrlen = GENL_HDRLEN + family->hdrsize;
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if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
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goto errout;
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ops = genl_get_cmd(hdr->cmd, family);
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if (ops == NULL) {
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err = -EOPNOTSUPP;
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goto errout;
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}
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if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb, CAP_NET_ADMIN)) {
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err = -EPERM;
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goto errout;
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}
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if (nlh->nlmsg_flags & NLM_F_DUMP) {
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if (ops->dumpit == NULL) {
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err = -EOPNOTSUPP;
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goto errout;
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}
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*errp = err = netlink_dump_start(genl_sock, skb, nlh,
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ops->dumpit, ops->done);
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if (err == 0)
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skb_pull(skb, min(NLMSG_ALIGN(nlh->nlmsg_len),
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skb->len));
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return -1;
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}
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if (ops->doit == NULL) {
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err = -EOPNOTSUPP;
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goto errout;
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}
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if (family->attrbuf) {
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err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
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ops->policy);
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if (err < 0)
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goto errout;
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}
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info.snd_seq = nlh->nlmsg_seq;
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info.snd_pid = NETLINK_CB(skb).pid;
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info.nlhdr = nlh;
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info.genlhdr = nlmsg_data(nlh);
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info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
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info.attrs = family->attrbuf;
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*errp = err = ops->doit(skb, &info);
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return err;
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ignore:
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return 0;
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errout:
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*errp = err;
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return -1;
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}
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static void genl_rcv(struct sock *sk, int len)
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{
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unsigned int qlen = 0;
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do {
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if (genl_trylock())
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return;
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netlink_run_queue(sk, &qlen, genl_rcv_msg);
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genl_unlock();
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} while (qlen && genl_sock && genl_sock->sk_receive_queue.qlen);
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}
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/**************************************************************************
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* Controller
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**************************************************************************/
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static struct genl_family genl_ctrl = {
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.id = GENL_ID_CTRL,
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.name = "nlctrl",
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.version = 0x2,
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.maxattr = CTRL_ATTR_MAX,
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};
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static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
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u32 flags, struct sk_buff *skb, u8 cmd)
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{
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void *hdr;
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hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
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if (hdr == NULL)
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return -1;
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NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
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NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
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NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
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NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
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NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
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if (!list_empty(&family->ops_list)) {
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struct nlattr *nla_ops;
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struct genl_ops *ops;
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int idx = 1;
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nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
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if (nla_ops == NULL)
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goto nla_put_failure;
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list_for_each_entry(ops, &family->ops_list, ops_list) {
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struct nlattr *nest;
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nest = nla_nest_start(skb, idx++);
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if (nest == NULL)
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goto nla_put_failure;
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NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
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NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
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nla_nest_end(skb, nest);
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}
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nla_nest_end(skb, nla_ops);
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}
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return genlmsg_end(skb, hdr);
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nla_put_failure:
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return genlmsg_cancel(skb, hdr);
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}
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static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
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{
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int i, n = 0;
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struct genl_family *rt;
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int chains_to_skip = cb->args[0];
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int fams_to_skip = cb->args[1];
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if (chains_to_skip != 0)
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genl_lock();
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for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
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if (i < chains_to_skip)
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continue;
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n = 0;
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list_for_each_entry(rt, genl_family_chain(i), family_list) {
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if (++n < fams_to_skip)
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continue;
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if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
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cb->nlh->nlmsg_seq, NLM_F_MULTI,
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skb, CTRL_CMD_NEWFAMILY) < 0)
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goto errout;
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}
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fams_to_skip = 0;
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}
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errout:
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if (chains_to_skip != 0)
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genl_unlock();
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cb->args[0] = i;
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cb->args[1] = n;
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return skb->len;
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}
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static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid,
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int seq, u8 cmd)
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{
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struct sk_buff *skb;
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int err;
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skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
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if (skb == NULL)
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return ERR_PTR(-ENOBUFS);
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err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
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if (err < 0) {
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nlmsg_free(skb);
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return ERR_PTR(err);
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}
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return skb;
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}
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static struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] __read_mostly = {
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[CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
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[CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
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.len = GENL_NAMSIZ - 1 },
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};
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static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
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{
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struct sk_buff *msg;
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struct genl_family *res = NULL;
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int err = -EINVAL;
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if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
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u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
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res = genl_family_find_byid(id);
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}
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if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
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char *name;
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name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
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res = genl_family_find_byname(name);
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}
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if (res == NULL) {
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err = -ENOENT;
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goto errout;
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}
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msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq,
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CTRL_CMD_NEWFAMILY);
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if (IS_ERR(msg)) {
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err = PTR_ERR(msg);
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goto errout;
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}
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err = genlmsg_reply(msg, info);
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errout:
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return err;
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}
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static int genl_ctrl_event(int event, void *data)
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{
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struct sk_buff *msg;
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if (genl_sock == NULL)
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return 0;
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switch (event) {
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case CTRL_CMD_NEWFAMILY:
|
|
case CTRL_CMD_DELFAMILY:
|
|
msg = ctrl_build_msg(data, 0, 0, event);
|
|
if (IS_ERR(msg))
|
|
return PTR_ERR(msg);
|
|
|
|
genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct genl_ops genl_ctrl_ops = {
|
|
.cmd = CTRL_CMD_GETFAMILY,
|
|
.doit = ctrl_getfamily,
|
|
.dumpit = ctrl_dumpfamily,
|
|
.policy = ctrl_policy,
|
|
};
|
|
|
|
static int __init genl_init(void)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
|
|
INIT_LIST_HEAD(&family_ht[i]);
|
|
|
|
err = genl_register_family(&genl_ctrl);
|
|
if (err < 0)
|
|
goto errout;
|
|
|
|
err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
|
|
if (err < 0)
|
|
goto errout_register;
|
|
|
|
netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
|
|
genl_sock = netlink_kernel_create(NETLINK_GENERIC, GENL_MAX_ID,
|
|
genl_rcv, THIS_MODULE);
|
|
if (genl_sock == NULL)
|
|
panic("GENL: Cannot initialize generic netlink\n");
|
|
|
|
return 0;
|
|
|
|
errout_register:
|
|
genl_unregister_family(&genl_ctrl);
|
|
errout:
|
|
panic("GENL: Cannot register controller: %d\n", err);
|
|
}
|
|
|
|
subsys_initcall(genl_init);
|
|
|
|
EXPORT_SYMBOL(genl_sock);
|
|
EXPORT_SYMBOL(genl_register_ops);
|
|
EXPORT_SYMBOL(genl_unregister_ops);
|
|
EXPORT_SYMBOL(genl_register_family);
|
|
EXPORT_SYMBOL(genl_unregister_family);
|