diff options
Diffstat (limited to 'net/netfilter/nfnetlink_acct.c')
| -rw-r--r-- | net/netfilter/nfnetlink_acct.c | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/net/netfilter/nfnetlink_acct.c b/net/netfilter/nfnetlink_acct.c new file mode 100644 index 000000000000..11ba013e47f6 --- /dev/null +++ b/net/netfilter/nfnetlink_acct.c @@ -0,0 +1,361 @@ +/* + * (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org> + * (C) 2011 Intra2net AG <http://www.intra2net.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/skbuff.h> +#include <linux/netlink.h> +#include <linux/rculist.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <net/netlink.h> +#include <net/sock.h> +#include <asm/atomic.h> + +#include <linux/netfilter.h> +#include <linux/netfilter/nfnetlink.h> +#include <linux/netfilter/nfnetlink_acct.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); +MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure"); + +static LIST_HEAD(nfnl_acct_list); + +struct nf_acct { + atomic64_t pkts; + atomic64_t bytes; + struct list_head head; + atomic_t refcnt; + char name[NFACCT_NAME_MAX]; + struct rcu_head rcu_head; +}; + +static int +nfnl_acct_new(struct sock *nfnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, const struct nlattr * const tb[]) +{ + struct nf_acct *nfacct, *matching = NULL; + char *acct_name; + + if (!tb[NFACCT_NAME]) + return -EINVAL; + + acct_name = nla_data(tb[NFACCT_NAME]); + + list_for_each_entry(nfacct, &nfnl_acct_list, head) { + if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0) + continue; + + if (nlh->nlmsg_flags & NLM_F_EXCL) + return -EEXIST; + + matching = nfacct; + break; + } + + if (matching) { + if (nlh->nlmsg_flags & NLM_F_REPLACE) { + /* reset counters if you request a replacement. */ + atomic64_set(&matching->pkts, 0); + atomic64_set(&matching->bytes, 0); + return 0; + } + return -EBUSY; + } + + nfacct = kzalloc(sizeof(struct nf_acct), GFP_KERNEL); + if (nfacct == NULL) + return -ENOMEM; + + strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX); + + if (tb[NFACCT_BYTES]) { + atomic64_set(&nfacct->bytes, + be64_to_cpu(nla_get_u64(tb[NFACCT_BYTES]))); + } + if (tb[NFACCT_PKTS]) { + atomic64_set(&nfacct->pkts, + be64_to_cpu(nla_get_u64(tb[NFACCT_PKTS]))); + } + atomic_set(&nfacct->refcnt, 1); + list_add_tail_rcu(&nfacct->head, &nfnl_acct_list); + return 0; +} + +static int +nfnl_acct_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type, + int event, struct nf_acct *acct) +{ + struct nlmsghdr *nlh; + struct nfgenmsg *nfmsg; + unsigned int flags = pid ? NLM_F_MULTI : 0; + u64 pkts, bytes; + + event |= NFNL_SUBSYS_ACCT << 8; + nlh = nlmsg_put(skb, pid, 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; + + NLA_PUT_STRING(skb, NFACCT_NAME, acct->name); + + if (type == NFNL_MSG_ACCT_GET_CTRZERO) { + pkts = atomic64_xchg(&acct->pkts, 0); + bytes = atomic64_xchg(&acct->bytes, 0); + } else { + pkts = atomic64_read(&acct->pkts); + bytes = atomic64_read(&acct->bytes); + } + NLA_PUT_BE64(skb, NFACCT_PKTS, cpu_to_be64(pkts)); + NLA_PUT_BE64(skb, NFACCT_BYTES, cpu_to_be64(bytes)); + NLA_PUT_BE32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt))); + + nlmsg_end(skb, nlh); + return skb->len; + +nlmsg_failure: +nla_put_failure: + nlmsg_cancel(skb, nlh); + return -1; +} + +static int +nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb) +{ + struct nf_acct *cur, *last; + + if (cb->args[2]) + return 0; + + last = (struct nf_acct *)cb->args[1]; + if (cb->args[1]) + cb->args[1] = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { + if (last && cur != last) + continue; + + if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).pid, + cb->nlh->nlmsg_seq, + NFNL_MSG_TYPE(cb->nlh->nlmsg_type), + NFNL_MSG_ACCT_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 +nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, const struct nlattr * const tb[]) +{ + int ret = -ENOENT; + struct nf_acct *cur; + char *acct_name; + + if (nlh->nlmsg_flags & NLM_F_DUMP) { + return netlink_dump_start(nfnl, skb, nlh, nfnl_acct_dump, + NULL, 0); + } + + if (!tb[NFACCT_NAME]) + return -EINVAL; + acct_name = nla_data(tb[NFACCT_NAME]); + + list_for_each_entry(cur, &nfnl_acct_list, head) { + struct sk_buff *skb2; + + if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) + continue; + + skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (skb2 == NULL) { + ret = -ENOMEM; + break; + } + + ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).pid, + nlh->nlmsg_seq, + NFNL_MSG_TYPE(nlh->nlmsg_type), + NFNL_MSG_ACCT_NEW, cur); + if (ret <= 0) { + kfree_skb(skb2); + break; + } + ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).pid, + 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 nfnl_acct_try_del(struct nf_acct *cur) +{ + int ret = 0; + + /* we want to avoid races with nfnl_acct_find_get. */ + if (atomic_dec_and_test(&cur->refcnt)) { + /* We are protected by nfnl mutex. */ + list_del_rcu(&cur->head); + kfree_rcu(cur, rcu_head); + } else { + /* still in use, restore reference counter. */ + atomic_inc(&cur->refcnt); + ret = -EBUSY; + } + return ret; +} + +static int +nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, const struct nlattr * const tb[]) +{ + char *acct_name; + struct nf_acct *cur; + int ret = -ENOENT; + + if (!tb[NFACCT_NAME]) { + list_for_each_entry(cur, &nfnl_acct_list, head) + nfnl_acct_try_del(cur); + + return 0; + } + acct_name = nla_data(tb[NFACCT_NAME]); + + list_for_each_entry(cur, &nfnl_acct_list, head) { + if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0) + continue; + + ret = nfnl_acct_try_del(cur); + if (ret < 0) + return ret; + + break; + } + return ret; +} + +static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = { + [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 }, + [NFACCT_BYTES] = { .type = NLA_U64 }, + [NFACCT_PKTS] = { .type = NLA_U64 }, +}; + +static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = { + [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new, + .attr_count = NFACCT_MAX, + .policy = nfnl_acct_policy }, + [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get, + .attr_count = NFACCT_MAX, + .policy = nfnl_acct_policy }, + [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get, + .attr_count = NFACCT_MAX, + .policy = nfnl_acct_policy }, + [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del, + .attr_count = NFACCT_MAX, + .policy = nfnl_acct_policy }, +}; + +static const struct nfnetlink_subsystem nfnl_acct_subsys = { + .name = "acct", + .subsys_id = NFNL_SUBSYS_ACCT, + .cb_count = NFNL_MSG_ACCT_MAX, + .cb = nfnl_acct_cb, +}; + +MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT); + +struct nf_acct *nfnl_acct_find_get(const char *acct_name) +{ + struct nf_acct *cur, *acct = NULL; + + rcu_read_lock(); + list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { + if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) + continue; + + if (!try_module_get(THIS_MODULE)) + goto err; + + if (!atomic_inc_not_zero(&cur->refcnt)) { + module_put(THIS_MODULE); + goto err; + } + + acct = cur; + break; + } +err: + rcu_read_unlock(); + return acct; +} +EXPORT_SYMBOL_GPL(nfnl_acct_find_get); + +void nfnl_acct_put(struct nf_acct *acct) +{ + atomic_dec(&acct->refcnt); + module_put(THIS_MODULE); +} +EXPORT_SYMBOL_GPL(nfnl_acct_put); + +void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct) +{ + atomic64_inc(&nfacct->pkts); + atomic64_add(skb->len, &nfacct->bytes); +} +EXPORT_SYMBOL_GPL(nfnl_acct_update); + +static int __init nfnl_acct_init(void) +{ + int ret; + + pr_info("nfnl_acct: registering with nfnetlink.\n"); + ret = nfnetlink_subsys_register(&nfnl_acct_subsys); + if (ret < 0) { + pr_err("nfnl_acct_init: cannot register with nfnetlink.\n"); + goto err_out; + } + return 0; +err_out: + return ret; +} + +static void __exit nfnl_acct_exit(void) +{ + struct nf_acct *cur, *tmp; + + pr_info("nfnl_acct: unregistering from nfnetlink.\n"); + nfnetlink_subsys_unregister(&nfnl_acct_subsys); + + list_for_each_entry_safe(cur, tmp, &nfnl_acct_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. */ + kfree_rcu(cur, rcu_head); + } +} + +module_init(nfnl_acct_init); +module_exit(nfnl_acct_exit); |