1 files changed, 579 insertions, 0 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
new file mode 100644
index 000000000000..287cfcc56951
--- /dev/null
+++ b/net/netlink/genetlink.c
@@ -0,0 +1,579 @@
+/*
+ * 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 <net/sock.h>
+#include <net/genetlink.h>
+
+struct sock *genl_sock = NULL;
+
+static DECLARE_MUTEX(genl_sem); /* serialization of message processing */
+
+static void genl_lock(void)
+{
+        down(&genl_sem);
+}
+
+static int genl_trylock(void)
+{
+        return down_trylock(&genl_sem);
+}
+
+static void genl_unlock(void)
+{
+        up(&genl_sem);
+
+        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 (!try_module_get(family->owner)) {
+                err = -EBUSY;
+                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;
+                }
+        } 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();
+
+                module_put(family->owner);
+                kfree(family->attrbuf);
+                genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
+                return 0;
+        }
+
+        genl_unlock();
+
+        return -ENOENT;
+}
+
+static inline 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, int 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,
+        .owner = THIS_MODULE,
+};
+
+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 -ENOMEM;
+        }
+
+        return 0;
+
+errout_register:
+        genl_unregister_family(&genl_ctrl);
+errout:
+        panic("GENL: Cannot register controller: %d\n", err);
+        return 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);