--- /dev/null
+/*
+ * NETLINK Generic Netlink Family
+ *
+ * Authors: Jamal Hadi Salim
+ * Thomas Graf <tgraf@suug.ch>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/mutex.h>
+#include <net/sock.h>
+#include <net/genetlink.h>
+
+struct sock *genl_sock = NULL;
+
+static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
+
+static void genl_lock(void)
+{
+ mutex_lock(&genl_mutex);
+}
+
+static int genl_trylock(void)
+{
+ return !mutex_trylock(&genl_mutex);
+}
+
+static void genl_unlock(void)
+{
+ mutex_unlock(&genl_mutex);
+
+ if (genl_sock && genl_sock->sk_receive_queue.qlen)
+ genl_sock->sk_data_ready(genl_sock, 0);
+}
+
+#define GENL_FAM_TAB_SIZE 16
+#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
+
+static struct list_head family_ht[GENL_FAM_TAB_SIZE];
+
+static int genl_ctrl_event(int event, void *data);
+
+static inline unsigned int genl_family_hash(unsigned int id)
+{
+ return id & GENL_FAM_TAB_MASK;
+}
+
+static inline struct list_head *genl_family_chain(unsigned int id)
+{
+ return &family_ht[genl_family_hash(id)];
+}
+
+static struct genl_family *genl_family_find_byid(unsigned int id)
+{
+ struct genl_family *f;
+
+ list_for_each_entry(f, genl_family_chain(id), family_list)
+ if (f->id == id)
+ return f;
+
+ return NULL;
+}
+
+static struct genl_family *genl_family_find_byname(char *name)
+{
+ struct genl_family *f;
+ int i;
+
+ for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
+ list_for_each_entry(f, genl_family_chain(i), family_list)
+ if (strcmp(f->name, name) == 0)
+ return f;
+
+ return NULL;
+}
+
+static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
+{
+ struct genl_ops *ops;
+
+ list_for_each_entry(ops, &family->ops_list, ops_list)
+ if (ops->cmd == cmd)
+ return ops;
+
+ return NULL;
+}
+
+/* Of course we are going to have problems once we hit
+ * 2^16 alive types, but that can only happen by year 2K
+*/
+static inline u16 genl_generate_id(void)
+{
+ static u16 id_gen_idx;
+ int overflowed = 0;
+
+ do {
+ if (id_gen_idx == 0)
+ id_gen_idx = GENL_MIN_ID;
+
+ if (++id_gen_idx > GENL_MAX_ID) {
+ if (!overflowed) {
+ overflowed = 1;
+ id_gen_idx = 0;
+ continue;
+ } else
+ return 0;
+ }
+
+ } while (genl_family_find_byid(id_gen_idx));
+
+ return id_gen_idx;
+}
+
+/**
+ * genl_register_ops - register generic netlink operations
+ * @family: generic netlink family
+ * @ops: operations to be registered
+ *
+ * Registers the specified operations and assigns them to the specified
+ * family. Either a doit or dumpit callback must be specified or the
+ * operation will fail. Only one operation structure per command
+ * identifier may be registered.
+ *
+ * See include/net/genetlink.h for more documenation on the operations
+ * structure.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
+{
+ int err = -EINVAL;
+
+ if (ops->dumpit == NULL && ops->doit == NULL)
+ goto errout;
+
+ if (genl_get_cmd(ops->cmd, family)) {
+ err = -EEXIST;
+ goto errout;
+ }
+
+ genl_lock();
+ list_add_tail(&ops->ops_list, &family->ops_list);
+ genl_unlock();
+
+ genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
+ err = 0;
+errout:
+ return err;
+}
+
+/**
+ * genl_unregister_ops - unregister generic netlink operations
+ * @family: generic netlink family
+ * @ops: operations to be unregistered
+ *
+ * Unregisters the specified operations and unassigns them from the
+ * specified family. The operation blocks until the current message
+ * processing has finished and doesn't start again until the
+ * unregister process has finished.
+ *
+ * Note: It is not necessary to unregister all operations before
+ * unregistering the family, unregistering the family will cause
+ * all assigned operations to be unregistered automatically.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
+{
+ struct genl_ops *rc;
+
+ genl_lock();
+ list_for_each_entry(rc, &family->ops_list, ops_list) {
+ if (rc == ops) {
+ list_del(&ops->ops_list);
+ genl_unlock();
+ genl_ctrl_event(CTRL_CMD_DELOPS, ops);
+ return 0;
+ }
+ }
+ genl_unlock();
+
+ return -ENOENT;
+}
+
+/**
+ * genl_register_family - register a generic netlink family
+ * @family: generic netlink family
+ *
+ * Registers the specified family after validating it first. Only one
+ * family may be registered with the same family name or identifier.
+ * The family id may equal GENL_ID_GENERATE causing an unique id to
+ * be automatically generated and assigned.
+ *
+ * Return 0 on success or a negative error code.
+ */
+int genl_register_family(struct genl_family *family)
+{
+ int err = -EINVAL;
+
+ if (family->id && family->id < GENL_MIN_ID)
+ goto errout;
+
+ if (family->id > GENL_MAX_ID)
+ goto errout;
+
+ INIT_LIST_HEAD(&family->ops_list);
+
+ genl_lock();
+
+ if (genl_family_find_byname(family->name)) {
+ err = -EEXIST;
+ goto errout_locked;
+ }
+
+ if (genl_family_find_byid(family->id)) {
+ err = -EEXIST;
+ goto errout_locked;
+ }
+
+ if (family->id == GENL_ID_GENERATE) {
+ u16 newid = genl_generate_id();
+
+ if (!newid) {
+ err = -ENOMEM;
+ goto errout_locked;
+ }
+
+ family->id = newid;
+ }
+
+ if (family->maxattr) {
+ family->attrbuf = kmalloc((family->maxattr+1) *
+ sizeof(struct nlattr *), GFP_KERNEL);
+ if (family->attrbuf == NULL) {
+ err = -ENOMEM;
+ goto errout_locked;
+ }
+ } else
+ family->attrbuf = NULL;
+
+ list_add_tail(&family->family_list, genl_family_chain(family->id));
+ genl_unlock();
+
+ genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
+
+ return 0;
+
+errout_locked:
+ genl_unlock();
+errout:
+ return err;
+}
+
+/**
+ * genl_unregister_family - unregister generic netlink family
+ * @family: generic netlink family
+ *
+ * Unregisters the specified family.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int genl_unregister_family(struct genl_family *family)
+{
+ struct genl_family *rc;
+
+ genl_lock();
+
+ list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
+ if (family->id != rc->id || strcmp(rc->name, family->name))
+ continue;
+
+ list_del(&rc->family_list);
+ INIT_LIST_HEAD(&family->ops_list);
+ genl_unlock();
+
+ kfree(family->attrbuf);
+ genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
+ return 0;
+ }
+
+ genl_unlock();
+
+ return -ENOENT;
+}
+
+static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
+ int *errp)
+{
+ struct genl_ops *ops;
+ struct genl_family *family;
+ struct genl_info info;
+ struct genlmsghdr *hdr = nlmsg_data(nlh);
+ int hdrlen, err = -EINVAL;
+
+ if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
+ goto ignore;
+
+ if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
+ goto ignore;
+
+ family = genl_family_find_byid(nlh->nlmsg_type);
+ if (family == NULL) {
+ err = -ENOENT;
+ goto errout;
+ }
+
+ hdrlen = GENL_HDRLEN + family->hdrsize;
+ if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+ goto errout;
+
+ ops = genl_get_cmd(hdr->cmd, family);
+ if (ops == NULL) {
+ err = -EOPNOTSUPP;
+ goto errout;
+ }
+
+ if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb)) {
+ err = -EPERM;
+ goto errout;
+ }
+
+ if (nlh->nlmsg_flags & NLM_F_DUMP) {
+ if (ops->dumpit == NULL) {
+ err = -EOPNOTSUPP;
+ goto errout;
+ }
+
+ *errp = err = netlink_dump_start(genl_sock, skb, nlh,
+ ops->dumpit, NULL);
+ if (err == 0)
+ skb_pull(skb, min(NLMSG_ALIGN(nlh->nlmsg_len),
+ skb->len));
+ return -1;
+ }
+
+ if (ops->doit == NULL) {
+ err = -EOPNOTSUPP;
+ goto errout;
+ }
+
+ if (family->attrbuf) {
+ err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
+ ops->policy);
+ if (err < 0)
+ goto errout;
+ }
+
+ info.snd_seq = nlh->nlmsg_seq;
+ info.snd_pid = NETLINK_CB(skb).pid;
+ info.nlhdr = nlh;
+ info.genlhdr = nlmsg_data(nlh);
+ info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
+ info.attrs = family->attrbuf;
+
+ *errp = err = ops->doit(skb, &info);
+ return err;
+
+ignore:
+ return 0;
+
+errout:
+ *errp = err;
+ return -1;
+}
+
+static void genl_rcv(struct sock *sk, int len)
+{
+ unsigned int qlen = 0;
+
+ do {
+ if (genl_trylock())
+ return;
+ netlink_run_queue(sk, &qlen, genl_rcv_msg);
+ genl_unlock();
+ } while (qlen && genl_sock && genl_sock->sk_receive_queue.qlen);
+}
+
+/**************************************************************************
+ * Controller
+ **************************************************************************/
+
+static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
+ u32 flags, struct sk_buff *skb, u8 cmd)
+{
+ void *hdr;
+
+ hdr = genlmsg_put(skb, pid, seq, GENL_ID_CTRL, 0, flags, cmd,
+ family->version);
+ if (hdr == NULL)
+ return -1;
+
+ NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
+ NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
+
+ return genlmsg_end(skb, hdr);
+
+nla_put_failure:
+ return genlmsg_cancel(skb, hdr);
+}
+
+static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
+{
+
+ int i, n = 0;
+ struct genl_family *rt;
+ int chains_to_skip = cb->args[0];
+ int fams_to_skip = cb->args[1];
+
+ for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
+ if (i < chains_to_skip)
+ continue;
+ n = 0;
+ list_for_each_entry(rt, genl_family_chain(i), family_list) {
+ if (++n < fams_to_skip)
+ continue;
+ if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
+ cb->nlh->nlmsg_seq, NLM_F_MULTI,
+ skb, CTRL_CMD_NEWFAMILY) < 0)
+ goto errout;
+ }
+
+ fams_to_skip = 0;
+ }
+
+errout:
+ cb->args[0] = i;
+ cb->args[1] = n;
+
+ return skb->len;
+}
+
+static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid,
+ int seq, u8 cmd)
+{
+ struct sk_buff *skb;
+ int err;
+
+ skb = nlmsg_new(NLMSG_GOODSIZE);
+ if (skb == NULL)
+ return ERR_PTR(-ENOBUFS);
+
+ err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
+ if (err < 0) {
+ nlmsg_free(skb);
+ return ERR_PTR(err);
+ }
+
+ return skb;
+}
+
+static struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] __read_mostly = {
+ [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
+ [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_STRING },
+};
+
+static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
+{
+ struct sk_buff *msg;
+ struct genl_family *res = NULL;
+ int err = -EINVAL;
+
+ if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
+ u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
+ res = genl_family_find_byid(id);
+ }
+
+ if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
+ char name[GENL_NAMSIZ];
+
+ if (nla_strlcpy(name, info->attrs[CTRL_ATTR_FAMILY_NAME],
+ GENL_NAMSIZ) >= GENL_NAMSIZ)
+ goto errout;
+
+ res = genl_family_find_byname(name);
+ }
+
+ if (res == NULL) {
+ err = -ENOENT;
+ goto errout;
+ }
+
+ msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq,
+ CTRL_CMD_NEWFAMILY);
+ if (IS_ERR(msg)) {
+ err = PTR_ERR(msg);
+ goto errout;
+ }
+
+ err = genlmsg_unicast(msg, info->snd_pid);
+errout:
+ return err;
+}
+
+static int genl_ctrl_event(int event, void *data)
+{
+ struct sk_buff *msg;
+
+ if (genl_sock == NULL)
+ return 0;
+
+ switch (event) {
+ 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);
+ break;
+ }
+
+ return 0;
+}
+
+static struct genl_ops genl_ctrl_ops = {
+ .cmd = CTRL_CMD_GETFAMILY,
+ .doit = ctrl_getfamily,
+ .dumpit = ctrl_dumpfamily,
+ .policy = ctrl_policy,
+};
+
+static struct genl_family genl_ctrl = {
+ .id = GENL_ID_CTRL,
+ .name = "nlctrl",
+ .version = 0x1,
+ .maxattr = CTRL_ATTR_MAX,
+};
+
+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);
git://git.onelab.eu / linux-2.6.git / blobdiff