diff options
Diffstat (limited to 'net/netfilter/nfnetlink_cttimeout.c')
| -rw-r--r-- | net/netfilter/nfnetlink_cttimeout.c | 585 |
1 files changed, 585 insertions, 0 deletions
diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c new file mode 100644 index 00000000000..476accd1714 --- /dev/null +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -0,0 +1,585 @@ +/* + * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org> + * (C) 2012 by Vyatta Inc. <http://www.vyatta.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation (or any later at your option). + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/rculist.h> +#include <linux/rculist_nulls.h> +#include <linux/types.h> +#include <linux/timer.h> +#include <linux/security.h> +#include <linux/skbuff.h> +#include <linux/errno.h> +#include <linux/netlink.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/slab.h> + +#include <linux/netfilter.h> +#include <net/netlink.h> +#include <net/sock.h> +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_core.h> +#include <net/netfilter/nf_conntrack_l3proto.h> +#include <net/netfilter/nf_conntrack_l4proto.h> +#include <net/netfilter/nf_conntrack_tuple.h> +#include <net/netfilter/nf_conntrack_timeout.h> + +#include <linux/netfilter/nfnetlink.h> +#include <linux/netfilter/nfnetlink_cttimeout.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); +MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning"); + +static LIST_HEAD(cttimeout_list); + +static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = { + [CTA_TIMEOUT_NAME] = { .type = NLA_NUL_STRING, + .len = CTNL_TIMEOUT_NAME_MAX - 1}, + [CTA_TIMEOUT_L3PROTO] = { .type = NLA_U16 }, + [CTA_TIMEOUT_L4PROTO] = { .type = NLA_U8 }, + [CTA_TIMEOUT_DATA] = { .type = NLA_NESTED }, +}; + +static int +ctnl_timeout_parse_policy(void *timeouts, struct nf_conntrack_l4proto *l4proto, + struct net *net, const struct nlattr *attr) +{ + int ret = 0; + + if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) { + struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1]; + + ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max, + attr, l4proto->ctnl_timeout.nla_policy); + if (ret < 0) + return ret; + + ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeouts); + } + return ret; +} + +static int +cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, + const struct nlattr * const cda[]) +{ + __u16 l3num; + __u8 l4num; + struct nf_conntrack_l4proto *l4proto; + struct ctnl_timeout *timeout, *matching = NULL; + struct net *net = sock_net(skb->sk); + char *name; + int ret; + + if (!cda[CTA_TIMEOUT_NAME] || + !cda[CTA_TIMEOUT_L3PROTO] || + !cda[CTA_TIMEOUT_L4PROTO] || + !cda[CTA_TIMEOUT_DATA]) + return -EINVAL; + + name = nla_data(cda[CTA_TIMEOUT_NAME]); + l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO])); + l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]); + + list_for_each_entry(timeout, &cttimeout_list, head) { + if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) + continue; + + if (nlh->nlmsg_flags & NLM_F_EXCL) + return -EEXIST; + + matching = timeout; + break; + } + + l4proto = nf_ct_l4proto_find_get(l3num, l4num); + + /* This protocol is not supportted, skip. */ + if (l4proto->l4proto != l4num) { + ret = -EOPNOTSUPP; + goto err_proto_put; + } + + if (matching) { + if (nlh->nlmsg_flags & NLM_F_REPLACE) { + /* You cannot replace one timeout policy by another of + * different kind, sorry. + */ + if (matching->l3num != l3num || + matching->l4proto->l4proto != l4num) { + ret = -EINVAL; + goto err_proto_put; + } + + ret = ctnl_timeout_parse_policy(&matching->data, + l4proto, net, + cda[CTA_TIMEOUT_DATA]); + return ret; + } + ret = -EBUSY; + goto err_proto_put; + } + + timeout = kzalloc(sizeof(struct ctnl_timeout) + + l4proto->ctnl_timeout.obj_size, GFP_KERNEL); + if (timeout == NULL) { + ret = -ENOMEM; + goto err_proto_put; + } + + ret = ctnl_timeout_parse_policy(&timeout->data, l4proto, net, + cda[CTA_TIMEOUT_DATA]); + if (ret < 0) + goto err; + + strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME])); + timeout->l3num = l3num; + timeout->l4proto = l4proto; + atomic_set(&timeout->refcnt, 1); + list_add_tail_rcu(&timeout->head, &cttimeout_list); + + return 0; +err: + kfree(timeout); +err_proto_put: + nf_ct_l4proto_put(l4proto); + return ret; +} + +static int +ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type, + int event, struct ctnl_timeout *timeout) +{ + struct nlmsghdr *nlh; + struct nfgenmsg *nfmsg; + unsigned int flags = portid ? NLM_F_MULTI : 0; + struct nf_conntrack_l4proto *l4proto = timeout->l4proto; + + event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8; + nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags); + if (nlh == NULL) + goto nlmsg_failure; + + nfmsg = nlmsg_data(nlh); + nfmsg->nfgen_family = AF_UNSPEC; + nfmsg->version = NFNETLINK_V0; + nfmsg->res_id = 0; + + if (nla_put_string(skb, CTA_TIMEOUT_NAME, timeout->name) || + nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)) || + nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) || + nla_put_be32(skb, CTA_TIMEOUT_USE, + htonl(atomic_read(&timeout->refcnt)))) + goto nla_put_failure; + + if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) { + struct nlattr *nest_parms; + int ret; + + nest_parms = nla_nest_start(skb, + CTA_TIMEOUT_DATA | NLA_F_NESTED); + if (!nest_parms) + goto nla_put_failure; + + ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data); + if (ret < 0) + goto nla_put_failure; + + nla_nest_end(skb, nest_parms); + } + + nlmsg_end(skb, nlh); + return skb->len; + +nlmsg_failure: +nla_put_failure: + nlmsg_cancel(skb, nlh); + return -1; +} + +static int +ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb) +{ + struct ctnl_timeout *cur, *last; + + if (cb->args[2]) + return 0; + + last = (struct ctnl_timeout *)cb->args[1]; + if (cb->args[1]) + cb->args[1] = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(cur, &cttimeout_list, head) { + if (last) { + if (cur != last) + continue; + + last = NULL; + } + if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, + NFNL_MSG_TYPE(cb->nlh->nlmsg_type), + IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) { + cb->args[1] = (unsigned long)cur; + break; + } + } + if (!cb->args[1]) + cb->args[2] = 1; + rcu_read_unlock(); + return skb->len; +} + +static int +cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, + const struct nlattr * const cda[]) +{ + int ret = -ENOENT; + char *name; + struct ctnl_timeout *cur; + + if (nlh->nlmsg_flags & NLM_F_DUMP) { + struct netlink_dump_control c = { + .dump = ctnl_timeout_dump, + }; + return netlink_dump_start(ctnl, skb, nlh, &c); + } + + if (!cda[CTA_TIMEOUT_NAME]) + return -EINVAL; + name = nla_data(cda[CTA_TIMEOUT_NAME]); + + list_for_each_entry(cur, &cttimeout_list, head) { + struct sk_buff *skb2; + + if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) + continue; + + skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (skb2 == NULL) { + ret = -ENOMEM; + break; + } + + ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid, + nlh->nlmsg_seq, + NFNL_MSG_TYPE(nlh->nlmsg_type), + IPCTNL_MSG_TIMEOUT_NEW, cur); + if (ret <= 0) { + kfree_skb(skb2); + break; + } + ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, + MSG_DONTWAIT); + if (ret > 0) + ret = 0; + + /* this avoids a loop in nfnetlink. */ + return ret == -EAGAIN ? -ENOBUFS : ret; + } + return ret; +} + +/* try to delete object, fail if it is still in use. */ +static int ctnl_timeout_try_del(struct ctnl_timeout *timeout) +{ + int ret = 0; + + /* we want to avoid races with nf_ct_timeout_find_get. */ + if (atomic_dec_and_test(&timeout->refcnt)) { + /* We are protected by nfnl mutex. */ + list_del_rcu(&timeout->head); + nf_ct_l4proto_put(timeout->l4proto); + kfree_rcu(timeout, rcu_head); + } else { + /* still in use, restore reference counter. */ + atomic_inc(&timeout->refcnt); + ret = -EBUSY; + } + return ret; +} + +static int +cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, + const struct nlattr * const cda[]) +{ + char *name; + struct ctnl_timeout *cur; + int ret = -ENOENT; + + if (!cda[CTA_TIMEOUT_NAME]) { + list_for_each_entry(cur, &cttimeout_list, head) + ctnl_timeout_try_del(cur); + + return 0; + } + name = nla_data(cda[CTA_TIMEOUT_NAME]); + + list_for_each_entry(cur, &cttimeout_list, head) { + if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) + continue; + + ret = ctnl_timeout_try_del(cur); + if (ret < 0) + return ret; + + break; + } + return ret; +} + +static int +cttimeout_default_set(struct sock *ctnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, + const struct nlattr * const cda[]) +{ + __u16 l3num; + __u8 l4num; + struct nf_conntrack_l4proto *l4proto; + struct net *net = sock_net(skb->sk); + unsigned int *timeouts; + int ret; + + if (!cda[CTA_TIMEOUT_L3PROTO] || + !cda[CTA_TIMEOUT_L4PROTO] || + !cda[CTA_TIMEOUT_DATA]) + return -EINVAL; + + l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO])); + l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]); + l4proto = nf_ct_l4proto_find_get(l3num, l4num); + + /* This protocol is not supported, skip. */ + if (l4proto->l4proto != l4num) { + ret = -EOPNOTSUPP; + goto err; + } + + timeouts = l4proto->get_timeouts(net); + + ret = ctnl_timeout_parse_policy(timeouts, l4proto, net, + cda[CTA_TIMEOUT_DATA]); + if (ret < 0) + goto err; + + nf_ct_l4proto_put(l4proto); + return 0; +err: + nf_ct_l4proto_put(l4proto); + return ret; +} + +static int +cttimeout_default_fill_info(struct net *net, struct sk_buff *skb, u32 portid, + u32 seq, u32 type, int event, + struct nf_conntrack_l4proto *l4proto) +{ + struct nlmsghdr *nlh; + struct nfgenmsg *nfmsg; + unsigned int flags = portid ? NLM_F_MULTI : 0; + + event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8; + nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags); + if (nlh == NULL) + goto nlmsg_failure; + + nfmsg = nlmsg_data(nlh); + nfmsg->nfgen_family = AF_UNSPEC; + nfmsg->version = NFNETLINK_V0; + nfmsg->res_id = 0; + + if (nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(l4proto->l3proto)) || + nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, l4proto->l4proto)) + goto nla_put_failure; + + if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) { + struct nlattr *nest_parms; + unsigned int *timeouts = l4proto->get_timeouts(net); + int ret; + + nest_parms = nla_nest_start(skb, + CTA_TIMEOUT_DATA | NLA_F_NESTED); + if (!nest_parms) + goto nla_put_failure; + + ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, timeouts); + if (ret < 0) + goto nla_put_failure; + + nla_nest_end(skb, nest_parms); + } + + nlmsg_end(skb, nlh); + return skb->len; + +nlmsg_failure: +nla_put_failure: + nlmsg_cancel(skb, nlh); + return -1; +} + +static int cttimeout_default_get(struct sock *ctnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, + const struct nlattr * const cda[]) +{ + __u16 l3num; + __u8 l4num; + struct nf_conntrack_l4proto *l4proto; + struct net *net = sock_net(skb->sk); + struct sk_buff *skb2; + int ret, err; + + if (!cda[CTA_TIMEOUT_L3PROTO] || !cda[CTA_TIMEOUT_L4PROTO]) + return -EINVAL; + + l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO])); + l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]); + l4proto = nf_ct_l4proto_find_get(l3num, l4num); + + /* This protocol is not supported, skip. */ + if (l4proto->l4proto != l4num) { + err = -EOPNOTSUPP; + goto err; + } + + skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (skb2 == NULL) { + err = -ENOMEM; + goto err; + } + + ret = cttimeout_default_fill_info(net, skb2, NETLINK_CB(skb).portid, + nlh->nlmsg_seq, + NFNL_MSG_TYPE(nlh->nlmsg_type), + IPCTNL_MSG_TIMEOUT_DEFAULT_SET, + l4proto); + if (ret <= 0) { + kfree_skb(skb2); + err = -ENOMEM; + goto err; + } + ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, MSG_DONTWAIT); + if (ret > 0) + ret = 0; + + /* this avoids a loop in nfnetlink. */ + return ret == -EAGAIN ? -ENOBUFS : ret; +err: + nf_ct_l4proto_put(l4proto); + return err; +} + +#ifdef CONFIG_NF_CONNTRACK_TIMEOUT +static struct ctnl_timeout *ctnl_timeout_find_get(const char *name) +{ + struct ctnl_timeout *timeout, *matching = NULL; + + rcu_read_lock(); + list_for_each_entry_rcu(timeout, &cttimeout_list, head) { + if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) + continue; + + if (!try_module_get(THIS_MODULE)) + goto err; + + if (!atomic_inc_not_zero(&timeout->refcnt)) { + module_put(THIS_MODULE); + goto err; + } + matching = timeout; + break; + } +err: + rcu_read_unlock(); + return matching; +} + +static void ctnl_timeout_put(struct ctnl_timeout *timeout) +{ + atomic_dec(&timeout->refcnt); + module_put(THIS_MODULE); +} +#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ + +static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = { + [IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout, + .attr_count = CTA_TIMEOUT_MAX, + .policy = cttimeout_nla_policy }, + [IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout, + .attr_count = CTA_TIMEOUT_MAX, + .policy = cttimeout_nla_policy }, + [IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout, + .attr_count = CTA_TIMEOUT_MAX, + .policy = cttimeout_nla_policy }, + [IPCTNL_MSG_TIMEOUT_DEFAULT_SET]= { .call = cttimeout_default_set, + .attr_count = CTA_TIMEOUT_MAX, + .policy = cttimeout_nla_policy }, + [IPCTNL_MSG_TIMEOUT_DEFAULT_GET]= { .call = cttimeout_default_get, + .attr_count = CTA_TIMEOUT_MAX, + .policy = cttimeout_nla_policy }, +}; + +static const struct nfnetlink_subsystem cttimeout_subsys = { + .name = "conntrack_timeout", + .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT, + .cb_count = IPCTNL_MSG_TIMEOUT_MAX, + .cb = cttimeout_cb, +}; + +MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT); + +static int __init cttimeout_init(void) +{ + int ret; + + ret = nfnetlink_subsys_register(&cttimeout_subsys); + if (ret < 0) { + pr_err("cttimeout_init: cannot register cttimeout with " + "nfnetlink.\n"); + goto err_out; + } +#ifdef CONFIG_NF_CONNTRACK_TIMEOUT + RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get); + RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put); +#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ + return 0; + +err_out: + return ret; +} + +static void __exit cttimeout_exit(void) +{ + struct ctnl_timeout *cur, *tmp; + + pr_info("cttimeout: unregistering from nfnetlink.\n"); + + nfnetlink_subsys_unregister(&cttimeout_subsys); + list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) { + list_del_rcu(&cur->head); + /* We are sure that our objects have no clients at this point, + * it's safe to release them all without checking refcnt. + */ + nf_ct_l4proto_put(cur->l4proto); + kfree_rcu(cur, rcu_head); + } +#ifdef CONFIG_NF_CONNTRACK_TIMEOUT + RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL); + RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL); +#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ +} + +module_init(cttimeout_init); +module_exit(cttimeout_exit); |