diff options
Diffstat (limited to 'net/netlink/genetlink.c')
| -rw-r--r-- | net/netlink/genetlink.c | 948 |
1 files changed, 948 insertions, 0 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c new file mode 100644 index 00000000..1781d991 --- /dev/null +++ b/net/netlink/genetlink.c @@ -0,0 +1,948 @@ +/* + * NETLINK Generic Netlink Family + * + * 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> + +static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ + +void genl_lock(void) +{ + mutex_lock(&genl_mutex); +} +EXPORT_SYMBOL(genl_lock); + +void genl_unlock(void) +{ + mutex_unlock(&genl_mutex); +} +EXPORT_SYMBOL(genl_unlock); + +#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); + +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 = GENL_MIN_ID; + int i; + + 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; + } + + 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 == ¬ify_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; + } + + grp->id = id; + set_bit(id, mc_groups); + list_add_tail(&grp->list, &family->mcast_groups); + grp->family = family; + + 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); +} + +/** + * 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; + } + + if (ops->dumpit) + ops->flags |= GENL_CMD_CAP_DUMP; + if (ops->doit) + ops->flags |= GENL_CMD_CAP_DO; + if (ops->policy) + ops->flags |= GENL_CMD_CAP_HASPOL; + + 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; +} +EXPORT_SYMBOL(genl_register_ops); + +/** + * 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; +} +EXPORT_SYMBOL(genl_unregister_ops); + +/** + * 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); + INIT_LIST_HEAD(&family->mcast_groups); + + genl_lock(); + + if (genl_family_find_byname(family->name)) { + 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; + } else if (genl_family_find_byid(family->id)) { + err = -EEXIST; + goto errout_locked; + } + + 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; +} +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 + * @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(); + + 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; + + 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; +} +EXPORT_SYMBOL(genl_unregister_family); + +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; + + family = genl_family_find_byid(nlh->nlmsg_type); + 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; + + ops = genl_get_cmd(hdr->cmd, family); + if (ops == NULL) + return -EOPNOTSUPP; + + if ((ops->flags & GENL_ADMIN_PERM) && + security_netlink_recv(skb, CAP_NET_ADMIN)) + return -EPERM; + + if (nlh->nlmsg_flags & NLM_F_DUMP) { + if (ops->dumpit == NULL) + return -EOPNOTSUPP; + + genl_unlock(); + err = netlink_dump_start(net->genl_sock, skb, nlh, + ops->dumpit, ops->done); + genl_lock(); + return err; + } + + if (ops->doit == NULL) + return -EOPNOTSUPP; + + if (family->attrbuf) { + err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr, + ops->policy); + if (err < 0) + return err; + } + + 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; + 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 err; +} + +static void genl_rcv(struct sk_buff *skb) +{ + genl_lock(); + netlink_rcv_skb(skb, &genl_rcv_msg); + genl_unlock(); +} + +/************************************************************************** + * Controller + **************************************************************************/ + +static struct genl_family genl_ctrl = { + .id = GENL_ID_CTRL, + .name = "nlctrl", + .version = 0x2, + .maxattr = CTRL_ATTR_MAX, + .netnsok = true, +}; + +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_ctrl, flags, cmd); + 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); + NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version); + NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize); + NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr); + + if (!list_empty(&family->ops_list)) { + struct nlattr *nla_ops; + struct genl_ops *ops; + int idx = 1; + + nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); + if (nla_ops == NULL) + goto nla_put_failure; + + list_for_each_entry(ops, &family->ops_list, ops_list) { + struct nlattr *nest; + + nest = nla_nest_start(skb, idx++); + if (nest == NULL) + goto nla_put_failure; + + NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd); + NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags); + + nla_nest_end(skb, nest); + } + + 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: + 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) +{ + + 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]; + + 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, + 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_family_msg(struct genl_family *family, + 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_info(family, pid, seq, 0, skb, cmd); + if (err < 0) { + nlmsg_free(skb); + return ERR_PTR(err); + } + + return skb; +} + +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 }, +}; + +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); + err = -ENOENT; + } + + if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { + char *name; + + name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); + res = genl_family_find_byname(name); + err = -ENOENT; + } + + 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)) + 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; + + /* genl is still initialising */ + if (!init_net.genl_sock) + return 0; + + switch (event) { + case CTRL_CMD_NEWFAMILY: + case CTRL_CMD_DELFAMILY: + 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; +} + +static struct genl_ops genl_ctrl_ops = { + .cmd = CTRL_CMD_GETFAMILY, + .doit = ctrl_getfamily, + .dumpit = ctrl_dumpfamily, + .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; + + for (i = 0; i < GENL_FAM_TAB_SIZE; i++) + INIT_LIST_HEAD(&family_ht[i]); + + err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1); + if (err < 0) + goto problem; + + netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV); + + err = register_pernet_subsys(&genl_pernet_ops); + if (err) + goto problem; + + err = genl_register_mc_group(&genl_ctrl, ¬ify_grp); + if (err < 0) + goto problem; + + return 0; + +problem: + panic("GENL: Cannot register controller: %d\n", err); +} + +subsys_initcall(genl_init); + +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); |