diff options
Diffstat (limited to 'net/netfilter/nfnetlink.c')
| -rw-r--r-- | net/netfilter/nfnetlink.c | 811 |
1 files changed, 811 insertions, 0 deletions
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c new file mode 100644 index 000000000..c9fbe0f70 --- /dev/null +++ b/net/netfilter/nfnetlink.c @@ -0,0 +1,811 @@ +/* Netfilter messages via netlink socket. Allows for user space + * protocol helpers and general trouble making from userspace. + * + * (C) 2001 by Jay Schulist <jschlst@samba.org>, + * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org> + * (C) 2005-2017 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * Initial netfilter messages via netlink development funded and + * generally made possible by Network Robots, Inc. (www.networkrobots.com) + * + * Further development of this code funded by Astaro AG (http://www.astaro.com) + * + * This software may be used and distributed according to the terms + * of the GNU General Public License, incorporated herein by reference. + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/skbuff.h> +#include <linux/uaccess.h> +#include <net/sock.h> +#include <linux/init.h> +#include <linux/sched/signal.h> + +#include <net/netlink.h> +#include <net/netns/generic.h> +#include <linux/netfilter.h> +#include <linux/netfilter/nfnetlink.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); +MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); +MODULE_DESCRIPTION("Netfilter messages via netlink socket"); + +#define nfnl_dereference_protected(id) \ + rcu_dereference_protected(table[(id)].subsys, \ + lockdep_nfnl_is_held((id))) + +#define NFNL_MAX_ATTR_COUNT 32 + +static unsigned int nfnetlink_pernet_id __read_mostly; + +#ifdef CONFIG_NF_CONNTRACK_EVENTS +static DEFINE_SPINLOCK(nfnl_grp_active_lock); +#endif + +struct nfnl_net { + struct sock *nfnl; +}; + +static struct { + struct mutex mutex; + const struct nfnetlink_subsystem __rcu *subsys; +} table[NFNL_SUBSYS_COUNT]; + +static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT]; + +static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = { + [NFNL_SUBSYS_NONE] = "nfnl_subsys_none", + [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink", + [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp", + [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue", + [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog", + [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf", + [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset", + [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct", + [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout", + [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper", + [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables", + [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat", + [NFNL_SUBSYS_HOOK] = "nfnl_subsys_hook", +}; + +static const int nfnl_group2type[NFNLGRP_MAX+1] = { + [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK, + [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK, + [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK, + [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP, + [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP, + [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP, + [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES, + [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT, + [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES, +}; + +static struct nfnl_net *nfnl_pernet(struct net *net) +{ + return net_generic(net, nfnetlink_pernet_id); +} + +void nfnl_lock(__u8 subsys_id) +{ + mutex_lock(&table[subsys_id].mutex); +} +EXPORT_SYMBOL_GPL(nfnl_lock); + +void nfnl_unlock(__u8 subsys_id) +{ + mutex_unlock(&table[subsys_id].mutex); +} +EXPORT_SYMBOL_GPL(nfnl_unlock); + +#ifdef CONFIG_PROVE_LOCKING +bool lockdep_nfnl_is_held(u8 subsys_id) +{ + return lockdep_is_held(&table[subsys_id].mutex); +} +EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held); +#endif + +int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) +{ + u8 cb_id; + + /* Sanity-check attr_count size to avoid stack buffer overflow. */ + for (cb_id = 0; cb_id < n->cb_count; cb_id++) + if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT)) + return -EINVAL; + + nfnl_lock(n->subsys_id); + if (table[n->subsys_id].subsys) { + nfnl_unlock(n->subsys_id); + return -EBUSY; + } + rcu_assign_pointer(table[n->subsys_id].subsys, n); + nfnl_unlock(n->subsys_id); + + return 0; +} +EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); + +int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) +{ + nfnl_lock(n->subsys_id); + table[n->subsys_id].subsys = NULL; + nfnl_unlock(n->subsys_id); + synchronize_rcu(); + return 0; +} +EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); + +static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type) +{ + u8 subsys_id = NFNL_SUBSYS_ID(type); + + if (subsys_id >= NFNL_SUBSYS_COUNT) + return NULL; + + return rcu_dereference(table[subsys_id].subsys); +} + +static inline const struct nfnl_callback * +nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss) +{ + u8 cb_id = NFNL_MSG_TYPE(type); + + if (cb_id >= ss->cb_count) + return NULL; + + return &ss->cb[cb_id]; +} + +int nfnetlink_has_listeners(struct net *net, unsigned int group) +{ + struct nfnl_net *nfnlnet = nfnl_pernet(net); + + return netlink_has_listeners(nfnlnet->nfnl, group); +} +EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); + +int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid, + unsigned int group, int echo, gfp_t flags) +{ + struct nfnl_net *nfnlnet = nfnl_pernet(net); + + return nlmsg_notify(nfnlnet->nfnl, skb, portid, group, echo, flags); +} +EXPORT_SYMBOL_GPL(nfnetlink_send); + +int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error) +{ + struct nfnl_net *nfnlnet = nfnl_pernet(net); + + return netlink_set_err(nfnlnet->nfnl, portid, group, error); +} +EXPORT_SYMBOL_GPL(nfnetlink_set_err); + +int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid) +{ + struct nfnl_net *nfnlnet = nfnl_pernet(net); + int err; + + err = nlmsg_unicast(nfnlnet->nfnl, skb, portid); + if (err == -EAGAIN) + err = -ENOBUFS; + + return err; +} +EXPORT_SYMBOL_GPL(nfnetlink_unicast); + +void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid, + __u32 group, gfp_t allocation) +{ + struct nfnl_net *nfnlnet = nfnl_pernet(net); + + netlink_broadcast(nfnlnet->nfnl, skb, portid, group, allocation); +} +EXPORT_SYMBOL_GPL(nfnetlink_broadcast); + +/* Process one complete nfnetlink message. */ +static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, + struct netlink_ext_ack *extack) +{ + struct net *net = sock_net(skb->sk); + const struct nfnl_callback *nc; + const struct nfnetlink_subsystem *ss; + int type, err; + + /* All the messages must at least contain nfgenmsg */ + if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) + return 0; + + type = nlh->nlmsg_type; +replay: + rcu_read_lock(); + + ss = nfnetlink_get_subsys(type); + if (!ss) { +#ifdef CONFIG_MODULES + rcu_read_unlock(); + request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); + rcu_read_lock(); + ss = nfnetlink_get_subsys(type); + if (!ss) +#endif + { + rcu_read_unlock(); + return -EINVAL; + } + } + + nc = nfnetlink_find_client(type, ss); + if (!nc) { + rcu_read_unlock(); + return -EINVAL; + } + + { + int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); + struct nfnl_net *nfnlnet = nfnl_pernet(net); + u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); + struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1]; + struct nlattr *attr = (void *)nlh + min_len; + int attrlen = nlh->nlmsg_len - min_len; + __u8 subsys_id = NFNL_SUBSYS_ID(type); + struct nfnl_info info = { + .net = net, + .sk = nfnlnet->nfnl, + .nlh = nlh, + .nfmsg = nlmsg_data(nlh), + .extack = extack, + }; + + /* Sanity-check NFNL_MAX_ATTR_COUNT */ + if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) { + rcu_read_unlock(); + return -ENOMEM; + } + + err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count, + attr, attrlen, + ss->cb[cb_id].policy, extack); + if (err < 0) { + rcu_read_unlock(); + return err; + } + + if (!nc->call) { + rcu_read_unlock(); + return -EINVAL; + } + + switch (nc->type) { + case NFNL_CB_RCU: + err = nc->call(skb, &info, (const struct nlattr **)cda); + rcu_read_unlock(); + break; + case NFNL_CB_MUTEX: + rcu_read_unlock(); + nfnl_lock(subsys_id); + if (nfnl_dereference_protected(subsys_id) != ss || + nfnetlink_find_client(type, ss) != nc) { + nfnl_unlock(subsys_id); + err = -EAGAIN; + break; + } + err = nc->call(skb, &info, (const struct nlattr **)cda); + nfnl_unlock(subsys_id); + break; + default: + rcu_read_unlock(); + err = -EINVAL; + break; + } + if (err == -EAGAIN) + goto replay; + return err; + } +} + +struct nfnl_err { + struct list_head head; + struct nlmsghdr *nlh; + int err; + struct netlink_ext_ack extack; +}; + +static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err, + const struct netlink_ext_ack *extack) +{ + struct nfnl_err *nfnl_err; + + nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL); + if (nfnl_err == NULL) + return -ENOMEM; + + nfnl_err->nlh = nlh; + nfnl_err->err = err; + nfnl_err->extack = *extack; + list_add_tail(&nfnl_err->head, list); + + return 0; +} + +static void nfnl_err_del(struct nfnl_err *nfnl_err) +{ + list_del(&nfnl_err->head); + kfree(nfnl_err); +} + +static void nfnl_err_reset(struct list_head *err_list) +{ + struct nfnl_err *nfnl_err, *next; + + list_for_each_entry_safe(nfnl_err, next, err_list, head) + nfnl_err_del(nfnl_err); +} + +static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb) +{ + struct nfnl_err *nfnl_err, *next; + + list_for_each_entry_safe(nfnl_err, next, err_list, head) { + netlink_ack(skb, nfnl_err->nlh, nfnl_err->err, + &nfnl_err->extack); + nfnl_err_del(nfnl_err); + } +} + +enum { + NFNL_BATCH_FAILURE = (1 << 0), + NFNL_BATCH_DONE = (1 << 1), + NFNL_BATCH_REPLAY = (1 << 2), +}; + +static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, + u16 subsys_id, u32 genid) +{ + struct sk_buff *oskb = skb; + struct net *net = sock_net(skb->sk); + const struct nfnetlink_subsystem *ss; + const struct nfnl_callback *nc; + struct netlink_ext_ack extack; + LIST_HEAD(err_list); + u32 status; + int err; + + if (subsys_id >= NFNL_SUBSYS_COUNT) + return netlink_ack(skb, nlh, -EINVAL, NULL); +replay: + status = 0; +replay_abort: + skb = netlink_skb_clone(oskb, GFP_KERNEL); + if (!skb) + return netlink_ack(oskb, nlh, -ENOMEM, NULL); + + nfnl_lock(subsys_id); + ss = nfnl_dereference_protected(subsys_id); + if (!ss) { +#ifdef CONFIG_MODULES + nfnl_unlock(subsys_id); + request_module("nfnetlink-subsys-%d", subsys_id); + nfnl_lock(subsys_id); + ss = nfnl_dereference_protected(subsys_id); + if (!ss) +#endif + { + nfnl_unlock(subsys_id); + netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); + return kfree_skb(skb); + } + } + + if (!ss->valid_genid || !ss->commit || !ss->abort) { + nfnl_unlock(subsys_id); + netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); + return kfree_skb(skb); + } + + if (!try_module_get(ss->owner)) { + nfnl_unlock(subsys_id); + netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); + return kfree_skb(skb); + } + + if (!ss->valid_genid(net, genid)) { + module_put(ss->owner); + nfnl_unlock(subsys_id); + netlink_ack(oskb, nlh, -ERESTART, NULL); + return kfree_skb(skb); + } + + nfnl_unlock(subsys_id); + + while (skb->len >= nlmsg_total_size(0)) { + int msglen, type; + + if (fatal_signal_pending(current)) { + nfnl_err_reset(&err_list); + err = -EINTR; + status = NFNL_BATCH_FAILURE; + goto done; + } + + memset(&extack, 0, sizeof(extack)); + nlh = nlmsg_hdr(skb); + err = 0; + + if (nlh->nlmsg_len < NLMSG_HDRLEN || + skb->len < nlh->nlmsg_len || + nlmsg_len(nlh) < sizeof(struct nfgenmsg)) { + nfnl_err_reset(&err_list); + status |= NFNL_BATCH_FAILURE; + goto done; + } + + /* Only requests are handled by the kernel */ + if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { + err = -EINVAL; + goto ack; + } + + type = nlh->nlmsg_type; + if (type == NFNL_MSG_BATCH_BEGIN) { + /* Malformed: Batch begin twice */ + nfnl_err_reset(&err_list); + status |= NFNL_BATCH_FAILURE; + goto done; + } else if (type == NFNL_MSG_BATCH_END) { + status |= NFNL_BATCH_DONE; + goto done; + } else if (type < NLMSG_MIN_TYPE) { + err = -EINVAL; + goto ack; + } + + /* We only accept a batch with messages for the same + * subsystem. + */ + if (NFNL_SUBSYS_ID(type) != subsys_id) { + err = -EINVAL; + goto ack; + } + + nc = nfnetlink_find_client(type, ss); + if (!nc) { + err = -EINVAL; + goto ack; + } + + if (nc->type != NFNL_CB_BATCH) { + err = -EINVAL; + goto ack; + } + + { + int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); + struct nfnl_net *nfnlnet = nfnl_pernet(net); + struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1]; + struct nlattr *attr = (void *)nlh + min_len; + u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); + int attrlen = nlh->nlmsg_len - min_len; + struct nfnl_info info = { + .net = net, + .sk = nfnlnet->nfnl, + .nlh = nlh, + .nfmsg = nlmsg_data(nlh), + .extack = &extack, + }; + + /* Sanity-check NFTA_MAX_ATTR */ + if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) { + err = -ENOMEM; + goto ack; + } + + err = nla_parse_deprecated(cda, + ss->cb[cb_id].attr_count, + attr, attrlen, + ss->cb[cb_id].policy, NULL); + if (err < 0) + goto ack; + + err = nc->call(skb, &info, (const struct nlattr **)cda); + + /* The lock was released to autoload some module, we + * have to abort and start from scratch using the + * original skb. + */ + if (err == -EAGAIN) { + status |= NFNL_BATCH_REPLAY; + goto done; + } + } +ack: + if (nlh->nlmsg_flags & NLM_F_ACK || err) { + /* Errors are delivered once the full batch has been + * processed, this avoids that the same error is + * reported several times when replaying the batch. + */ + if (err == -ENOMEM || + nfnl_err_add(&err_list, nlh, err, &extack) < 0) { + /* We failed to enqueue an error, reset the + * list of errors and send OOM to userspace + * pointing to the batch header. + */ + nfnl_err_reset(&err_list); + netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM, + NULL); + status |= NFNL_BATCH_FAILURE; + goto done; + } + /* We don't stop processing the batch on errors, thus, + * userspace gets all the errors that the batch + * triggers. + */ + if (err) + status |= NFNL_BATCH_FAILURE; + } + + msglen = NLMSG_ALIGN(nlh->nlmsg_len); + if (msglen > skb->len) + msglen = skb->len; + skb_pull(skb, msglen); + } +done: + if (status & NFNL_BATCH_REPLAY) { + ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD); + nfnl_err_reset(&err_list); + kfree_skb(skb); + module_put(ss->owner); + goto replay; + } else if (status == NFNL_BATCH_DONE) { + err = ss->commit(net, oskb); + if (err == -EAGAIN) { + status |= NFNL_BATCH_REPLAY; + goto done; + } else if (err) { + ss->abort(net, oskb, NFNL_ABORT_NONE); + netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL); + } + } else { + enum nfnl_abort_action abort_action; + + if (status & NFNL_BATCH_FAILURE) + abort_action = NFNL_ABORT_NONE; + else + abort_action = NFNL_ABORT_VALIDATE; + + err = ss->abort(net, oskb, abort_action); + if (err == -EAGAIN) { + nfnl_err_reset(&err_list); + kfree_skb(skb); + module_put(ss->owner); + status |= NFNL_BATCH_FAILURE; + goto replay_abort; + } + } + + nfnl_err_deliver(&err_list, oskb); + kfree_skb(skb); + module_put(ss->owner); +} + +static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = { + [NFNL_BATCH_GENID] = { .type = NLA_U32 }, +}; + +static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh) +{ + int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); + struct nlattr *attr = (void *)nlh + min_len; + struct nlattr *cda[NFNL_BATCH_MAX + 1]; + int attrlen = nlh->nlmsg_len - min_len; + struct nfgenmsg *nfgenmsg; + int msglen, err; + u32 gen_id = 0; + u16 res_id; + + msglen = NLMSG_ALIGN(nlh->nlmsg_len); + if (msglen > skb->len) + msglen = skb->len; + + if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) + return; + + err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen, + nfnl_batch_policy, NULL); + if (err < 0) { + netlink_ack(skb, nlh, err, NULL); + return; + } + if (cda[NFNL_BATCH_GENID]) + gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID])); + + nfgenmsg = nlmsg_data(nlh); + skb_pull(skb, msglen); + /* Work around old nft using host byte order */ + if (nfgenmsg->res_id == (__force __be16)NFNL_SUBSYS_NFTABLES) + res_id = NFNL_SUBSYS_NFTABLES; + else + res_id = ntohs(nfgenmsg->res_id); + + nfnetlink_rcv_batch(skb, nlh, res_id, gen_id); +} + +static void nfnetlink_rcv(struct sk_buff *skb) +{ + struct nlmsghdr *nlh = nlmsg_hdr(skb); + + if (skb->len < NLMSG_HDRLEN || + nlh->nlmsg_len < NLMSG_HDRLEN || + skb->len < nlh->nlmsg_len) + return; + + if (!netlink_net_capable(skb, CAP_NET_ADMIN)) { + netlink_ack(skb, nlh, -EPERM, NULL); + return; + } + + if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) + nfnetlink_rcv_skb_batch(skb, nlh); + else + netlink_rcv_skb(skb, nfnetlink_rcv_msg); +} + +static void nfnetlink_bind_event(struct net *net, unsigned int group) +{ +#ifdef CONFIG_NF_CONNTRACK_EVENTS + int type, group_bit; + u8 v; + + /* All NFNLGRP_CONNTRACK_* group bits fit into u8. + * The other groups are not relevant and can be ignored. + */ + if (group >= 8) + return; + + type = nfnl_group2type[group]; + + switch (type) { + case NFNL_SUBSYS_CTNETLINK: + break; + case NFNL_SUBSYS_CTNETLINK_EXP: + break; + default: + return; + } + + group_bit = (1 << group); + + spin_lock(&nfnl_grp_active_lock); + v = READ_ONCE(nf_ctnetlink_has_listener); + if ((v & group_bit) == 0) { + v |= group_bit; + + /* read concurrently without nfnl_grp_active_lock held. */ + WRITE_ONCE(nf_ctnetlink_has_listener, v); + } + + spin_unlock(&nfnl_grp_active_lock); +#endif +} + +static int nfnetlink_bind(struct net *net, int group) +{ + const struct nfnetlink_subsystem *ss; + int type; + + if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) + return 0; + + type = nfnl_group2type[group]; + + rcu_read_lock(); + ss = nfnetlink_get_subsys(type << 8); + rcu_read_unlock(); + if (!ss) + request_module_nowait("nfnetlink-subsys-%d", type); + + nfnetlink_bind_event(net, group); + return 0; +} + +static void nfnetlink_unbind(struct net *net, int group) +{ +#ifdef CONFIG_NF_CONNTRACK_EVENTS + int type, group_bit; + + if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) + return; + + type = nfnl_group2type[group]; + + switch (type) { + case NFNL_SUBSYS_CTNETLINK: + break; + case NFNL_SUBSYS_CTNETLINK_EXP: + break; + default: + return; + } + + /* ctnetlink_has_listener is u8 */ + if (group >= 8) + return; + + group_bit = (1 << group); + + spin_lock(&nfnl_grp_active_lock); + if (!nfnetlink_has_listeners(net, group)) { + u8 v = READ_ONCE(nf_ctnetlink_has_listener); + + v &= ~group_bit; + + /* read concurrently without nfnl_grp_active_lock held. */ + WRITE_ONCE(nf_ctnetlink_has_listener, v); + } + spin_unlock(&nfnl_grp_active_lock); +#endif +} + +static int __net_init nfnetlink_net_init(struct net *net) +{ + struct nfnl_net *nfnlnet = nfnl_pernet(net); + struct netlink_kernel_cfg cfg = { + .groups = NFNLGRP_MAX, + .input = nfnetlink_rcv, + .bind = nfnetlink_bind, + .unbind = nfnetlink_unbind, + }; + + nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); + if (!nfnlnet->nfnl) + return -ENOMEM; + return 0; +} + +static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) +{ + struct nfnl_net *nfnlnet; + struct net *net; + + list_for_each_entry(net, net_exit_list, exit_list) { + nfnlnet = nfnl_pernet(net); + + netlink_kernel_release(nfnlnet->nfnl); + } +} + +static struct pernet_operations nfnetlink_net_ops = { + .init = nfnetlink_net_init, + .exit_batch = nfnetlink_net_exit_batch, + .id = &nfnetlink_pernet_id, + .size = sizeof(struct nfnl_net), +}; + +static int __init nfnetlink_init(void) +{ + int i; + + for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++) + BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE); + + for (i=0; i<NFNL_SUBSYS_COUNT; i++) + __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]); + + return register_pernet_subsys(&nfnetlink_net_ops); +} + +static void __exit nfnetlink_exit(void) +{ + unregister_pernet_subsys(&nfnetlink_net_ops); +} +module_init(nfnetlink_init); +module_exit(nfnetlink_exit); |