netlink: add netlink_dump_control structure for netlink_dump_start()
[linux-flexiantxendom0-3.2.10.git] / net / netlink / genetlink.c
index 1b897bc..9f40441 100644 (file)
@@ -3,45 +3,58 @@
  *
  *             Authors:        Jamal Hadi Salim
  *                             Thomas Graf <tgraf@suug.ch>
+ *                             Johannes Berg <johannes@sipsolutions.net>
  */
 
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/slab.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 <linux/bitmap.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)
+void genl_lock(void)
 {
        mutex_lock(&genl_mutex);
 }
+EXPORT_SYMBOL(genl_lock);
 
-static int genl_trylock(void)
+void genl_unlock(void)
 {
-       return !mutex_trylock(&genl_mutex);
+       mutex_unlock(&genl_mutex);
 }
+EXPORT_SYMBOL(genl_unlock);
 
-static void genl_unlock(void)
+#ifdef CONFIG_PROVE_LOCKING
+int lockdep_genl_is_held(void)
 {
-       mutex_unlock(&genl_mutex);
-
-       if (genl_sock && genl_sock->sk_receive_queue.qlen)
-               genl_sock->sk_data_ready(genl_sock, 0);
+       return lockdep_is_held(&genl_mutex);
 }
+EXPORT_SYMBOL(lockdep_genl_is_held);
+#endif
 
 #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];
+/*
+ * Bitmap of multicast groups that are currently in use.
+ *
+ * To avoid an allocation at boot of just one unsigned long,
+ * declare it global instead.
+ * Bit 0 is marked as already used since group 0 is invalid.
+ */
+static unsigned long mc_group_start = 0x1;
+static unsigned long *mc_groups = &mc_group_start;
+static unsigned long mc_groups_longs = 1;
 
 static int genl_ctrl_event(int event, void *data);
 
@@ -93,27 +106,166 @@ static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
 /* 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 genl_generate_id(void)
 {
-       static u16 id_gen_idx;
-       int overflowed = 0;
+       static u16 id_gen_idx = GENL_MIN_ID;
+       int i;
 
-       do {
-               if (id_gen_idx == 0)
+       for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
+               if (!genl_family_find_byid(id_gen_idx))
+                       return id_gen_idx;
+               if (++id_gen_idx > GENL_MAX_ID)
                        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;
+       return 0;
+}
+
+static struct genl_multicast_group notify_grp;
+
+/**
+ * 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');
+
+       genl_lock();
+
+       /* special-case our own group */
+       if (grp == &notify_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 {
+               err = netlink_change_ngroups(init_net.genl_sock,
+                                            mc_groups_longs * BITS_PER_LONG);
+               if (err)
+                       goto out;
+       }
 
-       } while (genl_family_find_byid(id_gen_idx));
+       grp->id = id;
+       set_bit(id, mc_groups);
+       list_add_tail(&grp->list, &family->mcast_groups);
+       grp->family = family;
 
-       return id_gen_idx;
+       genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
+ out:
+       genl_unlock();
+       return err;
+}
+EXPORT_SYMBOL(genl_register_mc_group);
+
+static void __genl_unregister_mc_group(struct genl_family *family,
+                                      struct genl_multicast_group *grp)
+{
+       struct net *net;
+       BUG_ON(grp->family != family);
+
+       netlink_table_grab();
+       rcu_read_lock();
+       for_each_net_rcu(net)
+               __netlink_clear_multicast_users(net->genl_sock, grp->id);
+       rcu_read_unlock();
+       netlink_table_ungrab();
+
+       clear_bit(grp->id, mc_groups);
+       list_del(&grp->list);
+       genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
+       grp->id = 0;
+       grp->family = NULL;
+}
+
+/**
+ * genl_unregister_mc_group - unregister a multicast group
+ *
+ * Unregisters the specified multicast group and notifies userspace
+ * about it. All current listeners on the group are removed.
+ *
+ * Note: It is not necessary to unregister all multicast groups before
+ *       unregistering the family, unregistering the family will cause
+ *       all assigned multicast groups to be unregistered automatically.
+ *
+ * @family: Generic netlink family the group belongs to.
+ * @grp: The group to unregister, must have been registered successfully
+ *      previously.
+ */
+void genl_unregister_mc_group(struct genl_family *family,
+                             struct genl_multicast_group *grp)
+{
+       genl_lock();
+       __genl_unregister_mc_group(family, grp);
+       genl_unlock();
+}
+EXPORT_SYMBOL(genl_unregister_mc_group);
+
+static void genl_unregister_mc_groups(struct genl_family *family)
+{
+       struct genl_multicast_group *grp, *tmp;
+
+       list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
+               __genl_unregister_mc_group(family, grp);
 }
 
 /**
@@ -159,6 +311,7 @@ int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 errout:
        return err;
 }
+EXPORT_SYMBOL(genl_register_ops);
 
 /**
  * genl_unregister_ops - unregister generic netlink operations
@@ -193,6 +346,7 @@ int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 
        return -ENOENT;
 }
+EXPORT_SYMBOL(genl_unregister_ops);
 
 /**
  * genl_register_family - register a generic netlink family
@@ -216,6 +370,7 @@ int genl_register_family(struct genl_family *family)
                goto errout;
 
        INIT_LIST_HEAD(&family->ops_list);
+       INIT_LIST_HEAD(&family->mcast_groups);
 
        genl_lock();
 
@@ -224,11 +379,6 @@ int genl_register_family(struct genl_family *family)
                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();
 
@@ -238,6 +388,9 @@ int genl_register_family(struct genl_family *family)
                }
 
                family->id = newid;
+       } else if (genl_family_find_byid(family->id)) {
+               err = -EEXIST;
+               goto errout_locked;
        }
 
        if (family->maxattr) {
@@ -262,6 +415,53 @@ errout_locked:
 errout:
        return err;
 }
+EXPORT_SYMBOL(genl_register_family);
+
+/**
+ * genl_register_family_with_ops - register a generic netlink family
+ * @family: generic netlink family
+ * @ops: operations to be registered
+ * @n_ops: number of elements to register
+ *
+ * Registers the specified family and operations from the specified table.
+ * 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.
+ *
+ * Either a doit or dumpit callback must be specified for every registered
+ * operation or the function will fail. Only one operation structure per
+ * command identifier may be registered.
+ *
+ * See include/net/genetlink.h for more documenation on the operations
+ * structure.
+ *
+ * This is equivalent to calling genl_register_family() followed by
+ * genl_register_ops() for every operation entry in the table taking
+ * care to unregister the family on error path.
+ *
+ * Return 0 on success or a negative error code.
+ */
+int genl_register_family_with_ops(struct genl_family *family,
+       struct genl_ops *ops, size_t n_ops)
+{
+       int err, i;
+
+       err = genl_register_family(family);
+       if (err)
+               return err;
+
+       for (i = 0; i < n_ops; ++i, ++ops) {
+               err = genl_register_ops(family, ops);
+               if (err)
+                       goto err_out;
+       }
+       return 0;
+err_out:
+       genl_unregister_family(family);
+       return err;
+}
+EXPORT_SYMBOL(genl_register_family_with_ops);
 
 /**
  * genl_unregister_family - unregister generic netlink family
@@ -277,6 +477,8 @@ int genl_unregister_family(struct genl_family *family)
 
        genl_lock();
 
+       genl_unregister_mc_groups(family);
+
        list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
                if (family->id != rc->id || strcmp(rc->name, family->name))
                        continue;
@@ -294,11 +496,44 @@ int genl_unregister_family(struct genl_family *family)
 
        return -ENOENT;
 }
+EXPORT_SYMBOL(genl_unregister_family);
+
+/**
+ * genlmsg_put - Add generic netlink header to netlink message
+ * @skb: socket buffer holding the message
+ * @pid: netlink pid the message is addressed to
+ * @seq: sequence number (usually the one of the sender)
+ * @family: generic netlink family
+ * @flags netlink message flags
+ * @cmd: generic netlink command
+ *
+ * Returns pointer to user specific header
+ */
+void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
+                               struct genl_family *family, int flags, u8 cmd)
+{
+       struct nlmsghdr *nlh;
+       struct genlmsghdr *hdr;
+
+       nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN +
+                       family->hdrsize, flags);
+       if (nlh == NULL)
+               return NULL;
+
+       hdr = nlmsg_data(nlh);
+       hdr->cmd = cmd;
+       hdr->version = family->version;
+       hdr->reserved = 0;
+
+       return (char *) hdr + GENL_HDRLEN;
+}
+EXPORT_SYMBOL(genlmsg_put);
 
 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
        struct genl_ops *ops;
        struct genl_family *family;
+       struct net *net = sock_net(skb->sk);
        struct genl_info info;
        struct genlmsghdr *hdr = nlmsg_data(nlh);
        int hdrlen, err;
@@ -307,6 +542,10 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
        if (family == NULL)
                return -ENOENT;
 
+       /* this family doesn't exist in this netns */
+       if (!family->netnsok && !net_eq(net, &init_net))
+               return -ENOENT;
+
        hdrlen = GENL_HDRLEN + family->hdrsize;
        if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
                return -EINVAL;
@@ -316,17 +555,22 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                return -EOPNOTSUPP;
 
        if ((ops->flags & GENL_ADMIN_PERM) &&
-           security_netlink_recv(skb, CAP_NET_ADMIN))
+           !capable(CAP_NET_ADMIN))
                return -EPERM;
 
        if (nlh->nlmsg_flags & NLM_F_DUMP) {
                if (ops->dumpit == NULL)
                        return -EOPNOTSUPP;
 
-               err = netlink_dump_start(genl_sock, skb, nlh,
-                                        ops->dumpit, ops->done);
-               if (err == 0)
-                       err = -EINTR;
+               genl_unlock();
+               {
+                       struct netlink_dump_control c = {
+                               .dump = ops->dumpit,
+                               .done = ops->done,
+                       };
+                       err = netlink_dump_start(net->genl_sock, skb, nlh, &c);
+               }
+               genl_lock();
                return err;
        }
 
@@ -346,20 +590,28 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
        info.genlhdr = nlmsg_data(nlh);
        info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
        info.attrs = family->attrbuf;
+       genl_info_net_set(&info, net);
+       memset(&info.user_ptr, 0, sizeof(info.user_ptr));
+
+       if (family->pre_doit) {
+               err = family->pre_doit(ops, skb, &info);
+               if (err)
+                       return err;
+       }
+
+       err = ops->doit(skb, &info);
+
+       if (family->post_doit)
+               family->post_doit(ops, skb, &info);
 
-       return ops->doit(skb, &info);
+       return err;
 }
 
-static void genl_rcv(struct sock *sk, int len)
+static void genl_rcv(struct sk_buff *skb)
 {
-       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);
+       genl_lock();
+       netlink_rcv_skb(skb, &genl_rcv_msg);
+       genl_unlock();
 }
 
 /**************************************************************************
@@ -371,6 +623,7 @@ static struct genl_family genl_ctrl = {
        .name = "nlctrl",
        .version = 0x2,
        .maxattr = CTRL_ATTR_MAX,
+       .netnsok = true,
 };
 
 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
@@ -413,10 +666,73 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
                nla_nest_end(skb, nla_ops);
        }
 
+       if (!list_empty(&family->mcast_groups)) {
+               struct genl_multicast_group *grp;
+               struct nlattr *nla_grps;
+               int idx = 1;
+
+               nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+               if (nla_grps == NULL)
+                       goto nla_put_failure;
+
+               list_for_each_entry(grp, &family->mcast_groups, list) {
+                       struct nlattr *nest;
+
+                       nest = nla_nest_start(skb, idx++);
+                       if (nest == NULL)
+                               goto nla_put_failure;
+
+                       NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
+                       NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
+                                      grp->name);
+
+                       nla_nest_end(skb, nest);
+               }
+               nla_nest_end(skb, nla_grps);
+       }
+
        return genlmsg_end(skb, hdr);
 
 nla_put_failure:
-       return genlmsg_cancel(skb, hdr);
+       genlmsg_cancel(skb, hdr);
+       return -EMSGSIZE;
+}
+
+static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
+                               u32 seq, u32 flags, struct sk_buff *skb,
+                               u8 cmd)
+{
+       void *hdr;
+       struct nlattr *nla_grps;
+       struct nlattr *nest;
+
+       hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
+       if (hdr == NULL)
+               return -1;
+
+       NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
+       NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
+
+       nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+       if (nla_grps == NULL)
+               goto nla_put_failure;
+
+       nest = nla_nest_start(skb, 1);
+       if (nest == NULL)
+               goto nla_put_failure;
+
+       NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
+       NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
+                      grp->name);
+
+       nla_nest_end(skb, nest);
+       nla_nest_end(skb, nla_grps);
+
+       return genlmsg_end(skb, hdr);
+
+nla_put_failure:
+       genlmsg_cancel(skb, hdr);
+       return -EMSGSIZE;
 }
 
 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
@@ -424,17 +740,15 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 
        int i, n = 0;
        struct genl_family *rt;
+       struct net *net = sock_net(skb->sk);
        int chains_to_skip = cb->args[0];
        int fams_to_skip = cb->args[1];
 
-       if (chains_to_skip != 0)
-               genl_lock();
-
-       for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
-               if (i < chains_to_skip)
-                       continue;
+       for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
                n = 0;
                list_for_each_entry(rt, genl_family_chain(i), family_list) {
+                       if (!rt->netnsok && !net_eq(net, &init_net))
+                               continue;
                        if (++n < fams_to_skip)
                                continue;
                        if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
@@ -447,17 +761,14 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
        }
 
 errout:
-       if (chains_to_skip != 0)
-               genl_unlock();
-
        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)
+static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
+                                            u32 pid, int seq, u8 cmd)
 {
        struct sk_buff *skb;
        int err;
@@ -475,7 +786,26 @@ static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid,
        return skb;
 }
 
-static struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] __read_mostly = {
+static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
+                                           u32 pid, int seq, u8 cmd)
+{
+       struct sk_buff *skb;
+       int err;
+
+       skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+       if (skb == NULL)
+               return ERR_PTR(-ENOBUFS);
+
+       err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
+       if (err < 0) {
+               nlmsg_free(skb);
+               return ERR_PTR(err);
+       }
+
+       return skb;
+}
+
+static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
        [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
        [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
                                    .len = GENL_NAMSIZ - 1 },
@@ -490,6 +820,7 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
        if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
                u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
                res = genl_family_find_byid(id);
+               err = -ENOENT;
        }
 
        if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
@@ -497,41 +828,70 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 
                name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
                res = genl_family_find_byname(name);
-       }
-
-       if (res == NULL) {
+#ifdef CONFIG_MODULES
+               if (res == NULL) {
+                       genl_unlock();
+                       request_module("net-pf-%d-proto-%d-type-%s",
+                                      PF_NETLINK, NETLINK_GENERIC, name);
+                       genl_lock();
+                       res = genl_family_find_byname(name);
+               }
+#endif
                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;
+       if (res == NULL)
+               return err;
+
+       if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
+               /* family doesn't exist here */
+               return -ENOENT;
        }
 
-       err = genlmsg_reply(msg, info);
-errout:
-       return err;
+       msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
+                                   CTRL_CMD_NEWFAMILY);
+       if (IS_ERR(msg))
+               return PTR_ERR(msg);
+
+       return genlmsg_reply(msg, info);
 }
 
 static int genl_ctrl_event(int event, void *data)
 {
        struct sk_buff *msg;
+       struct genl_family *family;
+       struct genl_multicast_group *grp;
 
-       if (genl_sock == NULL)
+       /* genl is still initialising */
+       if (!init_net.genl_sock)
                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, GFP_KERNEL);
+               family = data;
+               msg = ctrl_build_family_msg(family, 0, 0, event);
                break;
+       case CTRL_CMD_NEWMCAST_GRP:
+       case CTRL_CMD_DELMCAST_GRP:
+               grp = data;
+               family = grp->family;
+               msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       if (IS_ERR(msg))
+               return PTR_ERR(msg);
+
+       if (!family->netnsok) {
+               genlmsg_multicast_netns(&init_net, msg, 0,
+                                       GENL_ID_CTRL, GFP_KERNEL);
+       } else {
+               rcu_read_lock();
+               genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
+               rcu_read_unlock();
        }
 
        return 0;
@@ -544,6 +904,37 @@ static struct genl_ops genl_ctrl_ops = {
        .policy         = ctrl_policy,
 };
 
+static struct genl_multicast_group notify_grp = {
+       .name           = "notify",
+};
+
+static int __net_init genl_pernet_init(struct net *net)
+{
+       /* we'll bump the group number right afterwards */
+       net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
+                                              genl_rcv, &genl_mutex,
+                                              THIS_MODULE);
+
+       if (!net->genl_sock && net_eq(net, &init_net))
+               panic("GENL: Cannot initialize generic netlink\n");
+
+       if (!net->genl_sock)
+               return -ENOMEM;
+
+       return 0;
+}
+
+static void __net_exit genl_pernet_exit(struct net *net)
+{
+       netlink_kernel_release(net->genl_sock);
+       net->genl_sock = NULL;
+}
+
+static struct pernet_operations genl_pernet_ops = {
+       .init = genl_pernet_init,
+       .exit = genl_pernet_exit,
+};
+
 static int __init genl_init(void)
 {
        int i, err;
@@ -551,32 +942,73 @@ static int __init genl_init(void)
        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);
+       err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
        if (err < 0)
-               goto errout_register;
+               goto problem;
 
        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");
+
+       err = register_pernet_subsys(&genl_pernet_ops);
+       if (err)
+               goto problem;
+
+       err = genl_register_mc_group(&genl_ctrl, &notify_grp);
+       if (err < 0)
+               goto problem;
 
        return 0;
 
-errout_register:
-       genl_unregister_family(&genl_ctrl);
-errout:
+problem:
        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);
+static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
+                        gfp_t flags)
+{
+       struct sk_buff *tmp;
+       struct net *net, *prev = NULL;
+       int err;
+
+       for_each_net_rcu(net) {
+               if (prev) {
+                       tmp = skb_clone(skb, flags);
+                       if (!tmp) {
+                               err = -ENOMEM;
+                               goto error;
+                       }
+                       err = nlmsg_multicast(prev->genl_sock, tmp,
+                                             pid, group, flags);
+                       if (err)
+                               goto error;
+               }
+
+               prev = net;
+       }
+
+       return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
+ error:
+       kfree_skb(skb);
+       return err;
+}
+
+int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
+                           gfp_t flags)
+{
+       return genlmsg_mcast(skb, pid, group, flags);
+}
+EXPORT_SYMBOL(genlmsg_multicast_allns);
+
+void genl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group,
+                struct nlmsghdr *nlh, gfp_t flags)
+{
+       struct sock *sk = net->genl_sock;
+       int report = 0;
+
+       if (nlh)
+               report = nlmsg_report(nlh);
+
+       nlmsg_notify(sk, skb, pid, group, report, flags);
+}
+EXPORT_SYMBOL(genl_notify);