diff options
Diffstat (limited to '')
| -rw-r--r-- | net/netlink/genetlink.c | 1096 |
1 files changed, 1096 insertions, 0 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c new file mode 100644 index 000000000..ede73ecfb --- /dev/null +++ b/net/netlink/genetlink.c @@ -0,0 +1,1096 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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 <linux/rwsem.h> +#include <linux/idr.h> +#include <net/sock.h> +#include <net/genetlink.h> + +static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ +static DECLARE_RWSEM(cb_lock); + +atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0); +DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq); + +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 +bool 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); +} + +static DEFINE_IDR(genl_fam_idr); + +/* + * 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 16 is marked as used since it's used for generic netlink + * and the code no longer marks pre-reserved IDs as used. + * 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. + * Bit 18 is marked as already used since the PMCRAID driver + * did the same thing as the VFS quota code (maybe copied?) + */ +static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | + BIT(GENL_ID_VFS_DQUOT) | + BIT(GENL_ID_PMCRAID); +static unsigned long *mc_groups = &mc_group_start; +static unsigned long mc_groups_longs = 1; + +static int genl_ctrl_event(int event, const struct genl_family *family, + const struct genl_multicast_group *grp, + int grp_id); + +static const struct genl_family *genl_family_find_byid(unsigned int id) +{ + return idr_find(&genl_fam_idr, id); +} + +static const struct genl_family *genl_family_find_byname(char *name) +{ + const struct genl_family *family; + unsigned int id; + + idr_for_each_entry(&genl_fam_idr, family, id) + if (strcmp(family->name, name) == 0) + return family; + + return NULL; +} + +static const struct genl_ops *genl_get_cmd(u8 cmd, + const 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; +} + +static int genl_allocate_reserve_groups(int n_groups, int *first_id) +{ + unsigned long *new_groups; + int start = 0; + int i; + int id; + bool fits; + + do { + if (start == 0) + id = find_first_zero_bit(mc_groups, + mc_groups_longs * + BITS_PER_LONG); + else + id = find_next_zero_bit(mc_groups, + mc_groups_longs * BITS_PER_LONG, + start); + + fits = true; + for (i = id; + i < min_t(int, id + n_groups, + mc_groups_longs * BITS_PER_LONG); + i++) { + if (test_bit(i, mc_groups)) { + start = i; + fits = false; + break; + } + } + + if (id + n_groups > mc_groups_longs * BITS_PER_LONG) { + unsigned long new_longs = mc_groups_longs + + BITS_TO_LONGS(n_groups); + size_t nlen = new_longs * sizeof(unsigned long); + + if (mc_groups == &mc_group_start) { + new_groups = kzalloc(nlen, GFP_KERNEL); + if (!new_groups) + return -ENOMEM; + mc_groups = new_groups; + *mc_groups = mc_group_start; + } else { + new_groups = krealloc(mc_groups, nlen, + GFP_KERNEL); + if (!new_groups) + return -ENOMEM; + mc_groups = new_groups; + for (i = 0; i < BITS_TO_LONGS(n_groups); i++) + mc_groups[mc_groups_longs + i] = 0; + } + mc_groups_longs = new_longs; + } + } while (!fits); + + for (i = id; i < id + n_groups; i++) + set_bit(i, mc_groups); + *first_id = id; + return 0; +} + +static struct genl_family genl_ctrl; + +static int genl_validate_assign_mc_groups(struct genl_family *family) +{ + int first_id; + int n_groups = family->n_mcgrps; + int err = 0, i; + bool groups_allocated = false; + + if (!n_groups) + return 0; + + for (i = 0; i < n_groups; i++) { + const struct genl_multicast_group *grp = &family->mcgrps[i]; + + if (WARN_ON(grp->name[0] == '\0')) + return -EINVAL; + if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL)) + return -EINVAL; + } + + /* special-case our own group and hacks */ + if (family == &genl_ctrl) { + first_id = GENL_ID_CTRL; + BUG_ON(n_groups != 1); + } else if (strcmp(family->name, "NET_DM") == 0) { + first_id = 1; + BUG_ON(n_groups != 1); + } else if (family->id == GENL_ID_VFS_DQUOT) { + first_id = GENL_ID_VFS_DQUOT; + BUG_ON(n_groups != 1); + } else if (family->id == GENL_ID_PMCRAID) { + first_id = GENL_ID_PMCRAID; + BUG_ON(n_groups != 1); + } else { + groups_allocated = true; + err = genl_allocate_reserve_groups(n_groups, &first_id); + if (err) + return err; + } + + family->mcgrp_offset = first_id; + + /* if still initializing, can't and don't need to to realloc bitmaps */ + if (!init_net.genl_sock) + return 0; + + 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. + */ + break; + } + } + rcu_read_unlock(); + netlink_table_ungrab(); + } else { + err = netlink_change_ngroups(init_net.genl_sock, + mc_groups_longs * BITS_PER_LONG); + } + + if (groups_allocated && err) { + for (i = 0; i < family->n_mcgrps; i++) + clear_bit(family->mcgrp_offset + i, mc_groups); + } + + return err; +} + +static void genl_unregister_mc_groups(const struct genl_family *family) +{ + struct net *net; + int i; + + netlink_table_grab(); + rcu_read_lock(); + for_each_net_rcu(net) { + for (i = 0; i < family->n_mcgrps; i++) + __netlink_clear_multicast_users( + net->genl_sock, family->mcgrp_offset + i); + } + rcu_read_unlock(); + netlink_table_ungrab(); + + for (i = 0; i < family->n_mcgrps; i++) { + int grp_id = family->mcgrp_offset + i; + + if (grp_id != 1) + clear_bit(grp_id, mc_groups); + genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, + &family->mcgrps[i], grp_id); + } +} + +static int genl_validate_ops(const 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; + } + + 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's ops, multicast groups and module pointer must already + * be assigned. + * + * Return 0 on success or a negative error code. + */ +int genl_register_family(struct genl_family *family) +{ + int err, i; + int start = GENL_START_ALLOC, end = GENL_MAX_ID; + + err = genl_validate_ops(family); + if (err) + return err; + + genl_lock_all(); + + if (genl_family_find_byname(family->name)) { + err = -EEXIST; + goto errout_locked; + } + + /* + * Sadly, a few cases need to be special-cased + * due to them having previously abused the API + * and having used their family ID also as their + * multicast group ID, so we use reserved IDs + * for both to be sure we can do that mapping. + */ + if (family == &genl_ctrl) { + /* and this needs to be special for initial family lookups */ + start = end = GENL_ID_CTRL; + } else if (strcmp(family->name, "pmcraid") == 0) { + start = end = GENL_ID_PMCRAID; + } else if (strcmp(family->name, "VFS_DQUOT") == 0) { + start = end = GENL_ID_VFS_DQUOT; + } + + if (family->maxattr && !family->parallel_ops) { + family->attrbuf = kmalloc_array(family->maxattr + 1, + sizeof(struct nlattr *), + GFP_KERNEL); + if (family->attrbuf == NULL) { + err = -ENOMEM; + goto errout_locked; + } + } else + family->attrbuf = NULL; + + family->id = idr_alloc(&genl_fam_idr, family, + start, end + 1, GFP_KERNEL); + if (family->id < 0) { + err = family->id; + goto errout_free; + } + + err = genl_validate_assign_mc_groups(family); + if (err) + goto errout_remove; + + genl_unlock_all(); + + /* send all events */ + genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0); + for (i = 0; i < family->n_mcgrps; i++) + genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, + &family->mcgrps[i], family->mcgrp_offset + i); + + return 0; + +errout_remove: + idr_remove(&genl_fam_idr, family->id); +errout_free: + kfree(family->attrbuf); +errout_locked: + genl_unlock_all(); + 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(const struct genl_family *family) +{ + genl_lock_all(); + + if (!genl_family_find_byid(family->id)) { + genl_unlock_all(); + return -ENOENT; + } + + genl_unregister_mc_groups(family); + + idr_remove(&genl_fam_idr, family->id); + + up_write(&cb_lock); + wait_event(genl_sk_destructing_waitq, + atomic_read(&genl_sk_destructing_cnt) == 0); + genl_unlock(); + + kfree(family->attrbuf); + + genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); + + return 0; +} +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, + const 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_start(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->start) { + genl_lock(); + rc = ops->start(cb); + genl_unlock(); + } + return rc; +} + +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(const struct genl_family *family, + struct sk_buff *skb, + struct nlmsghdr *nlh, + struct netlink_ext_ack *extack) +{ + 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) && + !netlink_capable(skb, CAP_NET_ADMIN)) + return -EPERM; + + if ((ops->flags & GENL_UNS_ADMIN_PERM) && + !netlink_ns_capable(skb, net->user_ns, 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, + .start = genl_lock_start, + .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, + .start = ops->start, + .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_array(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, extack); + 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; + info.extack = extack; + 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 netlink_ext_ack *extack) +{ + const 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, extack); + + 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; + +static int ctrl_fill_info(const 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 (family->n_mcgrps) { + struct nlattr *nla_grps; + int i; + + nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); + if (nla_grps == NULL) + goto nla_put_failure; + + for (i = 0; i < family->n_mcgrps; i++) { + struct nlattr *nest; + const struct genl_multicast_group *grp; + + grp = &family->mcgrps[i]; + + nest = nla_nest_start(skb, i + 1); + if (nest == NULL) + goto nla_put_failure; + + if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, + family->mcgrp_offset + i) || + 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); + } + + genlmsg_end(skb, hdr); + return 0; + +nla_put_failure: + genlmsg_cancel(skb, hdr); + return -EMSGSIZE; +} + +static int ctrl_fill_mcgrp_info(const struct genl_family *family, + const struct genl_multicast_group *grp, + int grp_id, 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, family->name) || + nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, 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); + + genlmsg_end(skb, hdr); + return 0; + +nla_put_failure: + genlmsg_cancel(skb, hdr); + return -EMSGSIZE; +} + +static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) +{ + int n = 0; + struct genl_family *rt; + struct net *net = sock_net(skb->sk); + int fams_to_skip = cb->args[0]; + unsigned int id; + + idr_for_each_entry(&genl_fam_idr, rt, id) { + 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) { + n--; + break; + } + } + + cb->args[0] = n; + return skb->len; +} + +static struct sk_buff *ctrl_build_family_msg(const 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(const struct genl_family *family, + const struct genl_multicast_group *grp, + int grp_id, 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(family, grp, grp_id, 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; + const 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, const struct genl_family *family, + const struct genl_multicast_group *grp, + int grp_id) +{ + struct sk_buff *msg; + + /* genl is still initialising */ + if (!init_net.genl_sock) + return 0; + + switch (event) { + case CTRL_CMD_NEWFAMILY: + case CTRL_CMD_DELFAMILY: + WARN_ON(grp); + msg = ctrl_build_family_msg(family, 0, 0, event); + break; + case CTRL_CMD_NEWMCAST_GRP: + case CTRL_CMD_DELMCAST_GRP: + BUG_ON(!grp); + msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); + break; + default: + return -EINVAL; + } + + if (IS_ERR(msg)) + return PTR_ERR(msg); + + if (!family->netnsok) { + genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, + 0, GFP_KERNEL); + } else { + rcu_read_lock(); + genlmsg_multicast_allns(&genl_ctrl, msg, 0, + 0, GFP_ATOMIC); + rcu_read_unlock(); + } + + return 0; +} + +static const struct genl_ops genl_ctrl_ops[] = { + { + .cmd = CTRL_CMD_GETFAMILY, + .doit = ctrl_getfamily, + .dumpit = ctrl_dumpfamily, + .policy = ctrl_policy, + }, +}; + +static const struct genl_multicast_group genl_ctrl_groups[] = { + { .name = "notify", }, +}; + +static struct genl_family genl_ctrl __ro_after_init = { + .module = THIS_MODULE, + .ops = genl_ctrl_ops, + .n_ops = ARRAY_SIZE(genl_ctrl_ops), + .mcgrps = genl_ctrl_groups, + .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups), + .id = GENL_ID_CTRL, + .name = "nlctrl", + .version = 0x2, + .maxattr = CTRL_ATTR_MAX, + .netnsok = true, +}; + +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 err; + + err = genl_register_family(&genl_ctrl); + if (err < 0) + goto problem; + + err = register_pernet_subsys(&genl_pernet_ops); + if (err) + goto problem; + + return 0; + +problem: + panic("GENL: Cannot register controller: %d\n", err); +} + +subsys_initcall(genl_init); + +/** + * genl_family_attrbuf - return family's attrbuf + * @family: the family + * + * Return the family's attrbuf, while validating that it's + * actually valid to access it. + * + * You cannot use this function with a family that has parallel_ops + * and you can only use it within (pre/post) doit/dumpit callbacks. + */ +struct nlattr **genl_family_attrbuf(const struct genl_family *family) +{ + if (!WARN_ON(family->parallel_ops)) + lockdep_assert_held(&genl_mutex); + + return family->attrbuf; +} +EXPORT_SYMBOL(genl_family_attrbuf); + +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; + bool delivered = false; + 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) + delivered = true; + else if (err != -ESRCH) + goto error; + } + + prev = net; + } + + err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); + if (!err) + delivered = true; + else if (err != -ESRCH) + return err; + return delivered ? 0 : -ESRCH; + error: + kfree_skb(skb); + return err; +} + +int genlmsg_multicast_allns(const struct genl_family *family, + struct sk_buff *skb, u32 portid, + unsigned int group, gfp_t flags) +{ + if (WARN_ON_ONCE(group >= family->n_mcgrps)) + return -EINVAL; + group = family->mcgrp_offset + group; + return genlmsg_mcast(skb, portid, group, flags); +} +EXPORT_SYMBOL(genlmsg_multicast_allns); + +void genl_notify(const struct genl_family *family, struct sk_buff *skb, + struct genl_info *info, u32 group, gfp_t flags) +{ + struct net *net = genl_info_net(info); + struct sock *sk = net->genl_sock; + int report = 0; + + if (info->nlhdr) + report = nlmsg_report(info->nlhdr); + + if (WARN_ON_ONCE(group >= family->n_mcgrps)) + return; + group = family->mcgrp_offset + group; + nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); +} +EXPORT_SYMBOL(genl_notify); |