/* * NETLINK Generic Netlink Family * * Authors: Jamal Hadi Salim * Thomas Graf * Johannes Berg */ #include #include #include #include #include #include #include #include #include #include #include #include #include static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ static DECLARE_RWSEM(cb_lock); void genl_lock(void) { mutex_lock(&genl_mutex); } EXPORT_SYMBOL(genl_lock); void genl_unlock(void) { mutex_unlock(&genl_mutex); } EXPORT_SYMBOL(genl_unlock); #ifdef CONFIG_LOCKDEP int lockdep_genl_is_held(void) { return lockdep_is_held(&genl_mutex); } EXPORT_SYMBOL(lockdep_genl_is_held); #endif static void genl_lock_all(void) { down_write(&cb_lock); genl_lock(); } static void genl_unlock_all(void) { genl_unlock(); up_write(&cb_lock); } #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. * Bit 1 is marked as already used since the drop-monitor code * abuses the API and thinks it can statically use group 1. * That group will typically conflict with other groups that * any proper users use. * Bit 17 is marked as already used since the VFS quota code * also abused this API and relied on family == group ID, we * cater to that by giving it a static family and group ID. */ static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_VFS_DQUOT); 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 const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) { int i; for (i = 0; i < family->n_ops; i++) if (family->ops[i].cmd == cmd) return &family->ops[i]; 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 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 (id_gen_idx != GENL_ID_VFS_DQUOT && !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'); BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL); genl_lock_all(); /* special-case our own group and hacks */ if (grp == ¬ify_grp) id = GENL_ID_CTRL; else if (strcmp(family->name, "NET_DM") == 0) id = 1; else if (strcmp(family->name, "VFS_DQUOT") == 0) id = GENL_ID_VFS_DQUOT; 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_all(); 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(); if (grp->id != 1) clear_bit(grp->id, mc_groups); list_del(&grp->list); genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp); grp->id = 0; grp->family = NULL; } 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); } static int genl_validate_ops(struct genl_family *family) { const struct genl_ops *ops = family->ops; unsigned int n_ops = family->n_ops; int i, j; if (WARN_ON(n_ops && !ops)) return -EINVAL; if (!n_ops) return 0; for (i = 0; i < n_ops; i++) { if (ops[i].dumpit == NULL && ops[i].doit == NULL) return -EINVAL; for (j = i + 1; j < n_ops; j++) if (ops[i].cmd == ops[j].cmd) return -EINVAL; } /* family is not registered yet, so no locking needed */ family->ops = ops; family->n_ops = n_ops; return 0; } /** * __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. * * The family's ops array must already be assigned, you can use the * genl_register_family_with_ops() helper function. * * 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; err = genl_validate_ops(family); if (err) return err; INIT_LIST_HEAD(&family->mcast_groups); genl_lock_all(); 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->parallel_ops) { 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_all(); genl_ctrl_event(CTRL_CMD_NEWFAMILY, family); return 0; errout_locked: genl_unlock_all(); errout: return err; } EXPORT_SYMBOL(__genl_register_family); /** * 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_all(); 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); family->n_ops = 0; genl_unlock_all(); kfree(family->attrbuf); genl_ctrl_event(CTRL_CMD_DELFAMILY, family); return 0; } genl_unlock_all(); return -ENOENT; } EXPORT_SYMBOL(genl_unregister_family); /** * genlmsg_put - Add generic netlink header to netlink message * @skb: socket buffer holding the message * @portid: netlink portid 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 portid, u32 seq, struct genl_family *family, int flags, u8 cmd) { struct nlmsghdr *nlh; struct genlmsghdr *hdr; nlh = nlmsg_put(skb, portid, 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_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) { /* our ops are always const - netlink API doesn't propagate that */ const struct genl_ops *ops = cb->data; int rc; genl_lock(); rc = ops->dumpit(skb, cb); genl_unlock(); return rc; } static int genl_lock_done(struct netlink_callback *cb) { /* our ops are always const - netlink API doesn't propagate that */ const struct genl_ops *ops = cb->data; int rc = 0; if (ops->done) { genl_lock(); rc = ops->done(cb); genl_unlock(); } return rc; } static int genl_family_rcv_msg(struct genl_family *family, struct sk_buff *skb, struct nlmsghdr *nlh) { const struct genl_ops *ops; struct net *net = sock_net(skb->sk); struct genl_info info; struct genlmsghdr *hdr = nlmsg_data(nlh); struct nlattr **attrbuf; int hdrlen, err; /* 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) && !capable(CAP_NET_ADMIN)) return -EPERM; if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) { int rc; if (ops->dumpit == NULL) return -EOPNOTSUPP; if (!family->parallel_ops) { struct netlink_dump_control c = { .module = family->module, /* we have const, but the netlink API doesn't */ .data = (void *)ops, .dump = genl_lock_dumpit, .done = genl_lock_done, }; genl_unlock(); rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); genl_lock(); } else { struct netlink_dump_control c = { .module = family->module, .dump = ops->dumpit, .done = ops->done, }; rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); } return rc; } if (ops->doit == NULL) return -EOPNOTSUPP; if (family->maxattr && family->parallel_ops) { attrbuf = kmalloc((family->maxattr+1) * sizeof(struct nlattr *), GFP_KERNEL); if (attrbuf == NULL) return -ENOMEM; } else attrbuf = family->attrbuf; if (attrbuf) { err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, ops->policy); if (err < 0) goto out; } info.snd_seq = nlh->nlmsg_seq; info.snd_portid = NETLINK_CB(skb).portid; info.nlhdr = nlh; info.genlhdr = nlmsg_data(nlh); info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; info.attrs = 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) goto out; } err = ops->doit(skb, &info); if (family->post_doit) family->post_doit(ops, skb, &info); out: if (family->parallel_ops) kfree(attrbuf); return err; } static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) { struct genl_family *family; int err; family = genl_family_find_byid(nlh->nlmsg_type); if (family == NULL) return -ENOENT; if (!family->parallel_ops) genl_lock(); err = genl_family_rcv_msg(family, skb, nlh); if (!family->parallel_ops) genl_unlock(); return err; } static void genl_rcv(struct sk_buff *skb) { down_read(&cb_lock); netlink_rcv_skb(skb, &genl_rcv_msg); up_read(&cb_lock); } /************************************************************************** * 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 portid, u32 seq, u32 flags, struct sk_buff *skb, u8 cmd) { void *hdr; hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); if (hdr == NULL) return -1; if (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)) goto nla_put_failure; if (family->n_ops) { struct nlattr *nla_ops; int i; nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); if (nla_ops == NULL) goto nla_put_failure; for (i = 0; i < family->n_ops; i++) { struct nlattr *nest; const struct genl_ops *ops = &family->ops[i]; u32 op_flags = ops->flags; if (ops->dumpit) op_flags |= GENL_CMD_CAP_DUMP; if (ops->doit) op_flags |= GENL_CMD_CAP_DO; if (ops->policy) op_flags |= GENL_CMD_CAP_HASPOL; nest = nla_nest_start(skb, i + 1); if (nest == NULL) goto nla_put_failure; if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) goto nla_put_failure; 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; if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) || nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, grp->name)) goto nla_put_failure; 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 portid, u32 seq, u32 flags, struct sk_buff *skb, u8 cmd) { void *hdr; struct nlattr *nla_grps; struct nlattr *nest; hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); if (hdr == NULL) return -1; if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) || nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id)) goto nla_put_failure; 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; if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) || nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, grp->name)) goto nla_put_failure; 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).portid, 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 portid, 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, portid, 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 portid, 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, portid, 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); #ifdef CONFIG_MODULES if (res == NULL) { genl_unlock(); up_read(&cb_lock); request_module("net-pf-%d-proto-%d-family-%s", PF_NETLINK, NETLINK_GENERIC, name); down_read(&cb_lock); genl_lock(); res = genl_family_find_byname(name); } #endif 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_portid, 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) { struct netlink_kernel_cfg cfg = { .input = genl_rcv, .flags = NL_CFG_F_NONROOT_RECV, }; /* we'll bump the group number right afterwards */ net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 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); if (err < 0) goto problem; 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 portid, 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, portid, group, flags); if (err) goto error; } prev = net; } return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); error: kfree_skb(skb); return err; } int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group, gfp_t flags) { return genlmsg_mcast(skb, portid, group, flags); } EXPORT_SYMBOL(genlmsg_multicast_allns); void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, 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, portid, group, report, flags); } EXPORT_SYMBOL(genl_notify);