#include <linux/genetlink.h>
 #include <net/netlink.h>
+#include <net/net_namespace.h>
 
 /**
  * struct genl_multicast_group - generic netlink multicast group
  * @name: name of family
  * @version: protocol version
  * @maxattr: maximum number of attributes supported
+ * @netnsok: set to true if the family can handle network
+ *     namespaces and should be presented in all of them
  * @attrbuf: buffer to store parsed attributes
  * @ops_list: list of all assigned operations
  * @family_list: family list
        char                    name[GENL_NAMSIZ];
        unsigned int            version;
        unsigned int            maxattr;
+       bool                    netnsok;
        struct nlattr **        attrbuf;        /* private */
        struct list_head        ops_list;       /* private */
        struct list_head        family_list;    /* private */
        struct genlmsghdr *     genlhdr;
        void *                  userhdr;
        struct nlattr **        attrs;
+#ifdef CONFIG_NET_NS
+       struct net *            _net;
+#endif
 };
 
+#ifdef CONFIG_NET_NS
+static inline struct net *genl_info_net(struct genl_info *info)
+{
+       return info->_net;
+}
+
+static inline void genl_info_net_set(struct genl_info *info, struct net *net)
+{
+       info->_net = net;
+}
+#else
+static inline struct net *genl_info_net(struct genl_info *info)
+{
+       return &init_net;
+}
+
+static inline void genl_info_net_set(struct genl_info *info, struct net *net)
+{
+}
+#endif
+
 /**
  * struct genl_ops - generic netlink operations
  * @cmd: command identifier
 extern void genl_unregister_mc_group(struct genl_family *family,
                                     struct genl_multicast_group *grp);
 
-extern struct sock *genl_sock;
-
 /**
  * genlmsg_put - Add generic netlink header to netlink message
  * @skb: socket buffer holding the message
 }
 
 /**
- * genlmsg_multicast - multicast a netlink message
+ * genlmsg_multicast_netns - multicast a netlink message to a specific netns
+ * @net: the net namespace
+ * @skb: netlink message as socket buffer
+ * @pid: own netlink pid to avoid sending to yourself
+ * @group: multicast group id
+ * @flags: allocation flags
+ */
+static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
+                                         u32 pid, unsigned int group, gfp_t flags)
+{
+       return nlmsg_multicast(net->genl_sock, skb, pid, group, flags);
+}
+
+/**
+ * genlmsg_multicast - multicast a netlink message to the default netns
  * @skb: netlink message as socket buffer
  * @pid: own netlink pid to avoid sending to yourself
  * @group: multicast group id
 static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid,
                                    unsigned int group, gfp_t flags)
 {
-       return nlmsg_multicast(genl_sock, skb, pid, group, flags);
+       return genlmsg_multicast_netns(&init_net, skb, pid, group, flags);
 }
 
+/**
+ * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
+ * @skb: netlink message as socket buffer
+ * @pid: own netlink pid to avoid sending to yourself
+ * @group: multicast group id
+ * @flags: allocation flags
+ *
+ * This function must hold the RTNL or rcu_read_lock().
+ */
+int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid,
+                           unsigned int group, gfp_t flags);
+
 /**
  * genlmsg_unicast - unicast a netlink message
  * @skb: netlink message as socket buffer
  * @pid: netlink pid of the destination socket
  */
-static inline int genlmsg_unicast(struct sk_buff *skb, u32 pid)
+static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 pid)
 {
-       return nlmsg_unicast(genl_sock, skb, pid);
+       return nlmsg_unicast(net->genl_sock, skb, pid);
 }
 
 /**
  */
 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
 {
-       return genlmsg_unicast(skb, info->snd_pid);
+       return genlmsg_unicast(genl_info_net(info), skb, info->snd_pid);
 }
 
 /**
 
 #include <net/sock.h>
 #include <net/genetlink.h>
 
-struct sock *genl_sock = NULL;
-
 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
 
 static inline void genl_lock(void)
                mc_groups_longs++;
        }
 
-       err = netlink_change_ngroups(genl_sock,
-                                    mc_groups_longs * BITS_PER_LONG);
-       if (err)
-               goto out;
+       if (family->netnsok) {
+               struct net *net;
+
+               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();
+                               goto out;
+                       }
+               }
+               rcu_read_unlock();
+       } else {
+               err = netlink_change_ngroups(init_net.genl_sock,
+                                            mc_groups_longs * BITS_PER_LONG);
+               if (err)
+                       goto out;
+       }
 
        grp->id = id;
        set_bit(id, mc_groups);
 static void __genl_unregister_mc_group(struct genl_family *family,
                                       struct genl_multicast_group *grp)
 {
+       struct net *net;
        BUG_ON(grp->family != family);
-       netlink_clear_multicast_users(genl_sock, grp->id);
+
+       rcu_read_lock();
+       for_each_net_rcu(net)
+               netlink_clear_multicast_users(net->genl_sock, grp->id);
+       rcu_read_unlock();
+
        clear_bit(grp->id, mc_groups);
        list_del(&grp->list);
        genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 {
        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;
        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;
                        return -EOPNOTSUPP;
 
                genl_unlock();
-               err = netlink_dump_start(genl_sock, skb, nlh,
+               err = netlink_dump_start(net->genl_sock, skb, nlh,
                                         ops->dumpit, ops->done);
                genl_lock();
                return err;
        info.genlhdr = nlmsg_data(nlh);
        info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
        info.attrs = family->attrbuf;
+       genl_info_net_set(&info, net);
 
        return ops->doit(skb, &info);
 }
        .name = "nlctrl",
        .version = 0x2,
        .maxattr = CTRL_ATTR_MAX,
+       .netnsok = true,
 };
 
 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 
        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];
 
                        continue;
                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,
        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]) {
 
                name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
                res = genl_family_find_byname(name);
+               err = -ENOENT;
        }
 
-       if (res == NULL) {
-               err = -ENOENT;
-               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;
        }
 
        msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
                                    CTRL_CMD_NEWFAMILY);
-       if (IS_ERR(msg)) {
-               err = PTR_ERR(msg);
-               goto errout;
-       }
+       if (IS_ERR(msg))
+               return PTR_ERR(msg);
 
-       err = genlmsg_reply(msg, info);
-errout:
-       return err;
+       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_family_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);
-               if (IS_ERR(msg))
-                       return PTR_ERR(msg);
-
-               genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
                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;
        .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;
 
        err = genl_register_family(&genl_ctrl);
        if (err < 0)
-               goto errout;
+               goto problem;
 
        err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
        if (err < 0)
-               goto errout_register;
+               goto problem;
 
        netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 
-       /* we'll bump the group number right afterwards */
-       genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
-                                         genl_rcv, &genl_mutex, 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, ¬ify_grp);
        if (err < 0)
-               goto errout_register;
+               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);
 
 
        cfg80211_unlock_rdev(dev);
 
-       return genlmsg_unicast(msg, info->snd_pid);
+       return genlmsg_reply(msg, info);
 
  out_free:
        nlmsg_free(msg);
        dev_put(netdev);
        cfg80211_unlock_rdev(dev);
 
-       return genlmsg_unicast(msg, info->snd_pid);
+       return genlmsg_reply(msg, info);
 
  out_free:
        nlmsg_free(msg);
                goto nla_put_failure;
 
        genlmsg_end(msg, hdr);
-       err = genlmsg_unicast(msg, info->snd_pid);
+       err = genlmsg_reply(msg, info);
        goto out;
 
  nla_put_failure:
                                 dev, mac_addr, &sinfo) < 0)
                goto out_free;
 
-       err = genlmsg_unicast(msg, info->snd_pid);
+       err = genlmsg_reply(msg, info);
        goto out;
 
  out_free:
                                 dev, dst, next_hop, &pinfo) < 0)
                goto out_free;
 
-       err = genlmsg_unicast(msg, info->snd_pid);
+       err = genlmsg_reply(msg, info);
        goto out;
 
  out_free:
                        cur_params.dot11MeshHWMPnetDiameterTraversalTime);
        nla_nest_end(msg, pinfoattr);
        genlmsg_end(msg, hdr);
-       err = genlmsg_unicast(msg, info->snd_pid);
+       err = genlmsg_reply(msg, info);
        goto out;
 
  nla_put_failure:
        nla_nest_end(msg, nl_reg_rules);
 
        genlmsg_end(msg, hdr);
-       err = genlmsg_unicast(msg, info->snd_pid);
+       err = genlmsg_reply(msg, info);
        goto out;
 
 nla_put_failure: