Commit 9cb01766 authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
Browse files

netfilter: add glue code to integrate nfnetlink_queue and ctnetlink



This patch allows you to include the conntrack information together
with the packet that is sent to user-space via NFQUEUE.

Previously, there was no integration between ctnetlink and
nfnetlink_queue. If you wanted to access conntrack information
from your libnetfilter_queue program, you required to query
ctnetlink from user-space to obtain it. Thus, delaying the packet
processing even more.

Including the conntrack information is optional, you can set it
via NFQA_CFG_F_CONNTRACK flag with the new NFQA_CFG_FLAGS attribute.
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 1afc5679
......@@ -393,6 +393,16 @@ nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *) __rcu;
extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
struct nf_conn;
struct nlattr;
struct nfq_ct_hook {
size_t (*build_size)(const struct nf_conn *ct);
int (*build)(struct sk_buff *skb, struct nf_conn *ct);
int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
};
extern struct nfq_ct_hook *nfq_ct_hook;
#else
static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
#endif
......
......@@ -42,6 +42,8 @@ enum nfqnl_attr_type {
NFQA_IFINDEX_PHYSOUTDEV, /* __u32 ifindex */
NFQA_HWADDR, /* nfqnl_msg_packet_hw */
NFQA_PAYLOAD, /* opaque data payload */
NFQA_CT, /* nf_conntrack_netlink.h */
NFQA_CT_INFO, /* enum ip_conntrack_info */
__NFQA_MAX
};
......@@ -92,5 +94,6 @@ enum nfqnl_attr_config {
/* Flags for NFQA_CFG_FLAGS */
#define NFQA_CFG_F_FAIL_OPEN (1 << 0)
#define NFQA_CFG_F_CONNTRACK (1 << 1)
#endif /* _NFNETLINK_QUEUE_H */
......@@ -264,6 +264,10 @@ void nf_conntrack_destroy(struct nf_conntrack *nfct)
rcu_read_unlock();
}
EXPORT_SYMBOL(nf_conntrack_destroy);
struct nfq_ct_hook *nfq_ct_hook;
EXPORT_SYMBOL_GPL(nfq_ct_hook);
#endif /* CONFIG_NF_CONNTRACK */
#ifdef CONFIG_PROC_FS
......
......@@ -1620,6 +1620,140 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
return err;
}
#if defined(CONFIG_NETFILTER_NETLINK_QUEUE) || \
defined(CONFIG_NETFILTER_NETLINK_QUEUE_MODULE)
static size_t
ctnetlink_nfqueue_build_size(const struct nf_conn *ct)
{
return 3 * nla_total_size(0) /* CTA_TUPLE_ORIG|REPL|MASTER */
+ 3 * nla_total_size(0) /* CTA_TUPLE_IP */
+ 3 * nla_total_size(0) /* CTA_TUPLE_PROTO */
+ 3 * nla_total_size(sizeof(u_int8_t)) /* CTA_PROTO_NUM */
+ nla_total_size(sizeof(u_int32_t)) /* CTA_ID */
+ nla_total_size(sizeof(u_int32_t)) /* CTA_STATUS */
+ nla_total_size(sizeof(u_int32_t)) /* CTA_TIMEOUT */
+ nla_total_size(0) /* CTA_PROTOINFO */
+ nla_total_size(0) /* CTA_HELP */
+ nla_total_size(NF_CT_HELPER_NAME_LEN) /* CTA_HELP_NAME */
+ ctnetlink_secctx_size(ct)
#ifdef CONFIG_NF_NAT_NEEDED
+ 2 * nla_total_size(0) /* CTA_NAT_SEQ_ADJ_ORIG|REPL */
+ 6 * nla_total_size(sizeof(u_int32_t)) /* CTA_NAT_SEQ_OFFSET */
#endif
#ifdef CONFIG_NF_CONNTRACK_MARK
+ nla_total_size(sizeof(u_int32_t)) /* CTA_MARK */
#endif
+ ctnetlink_proto_size(ct)
;
}
static int
ctnetlink_nfqueue_build(struct sk_buff *skb, struct nf_conn *ct)
{
struct nlattr *nest_parms;
rcu_read_lock();
nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);
if (!nest_parms)
goto nla_put_failure;
if (ctnetlink_dump_tuples(skb, nf_ct_tuple(ct, IP_CT_DIR_ORIGINAL)) < 0)
goto nla_put_failure;
nla_nest_end(skb, nest_parms);
nest_parms = nla_nest_start(skb, CTA_TUPLE_REPLY | NLA_F_NESTED);
if (!nest_parms)
goto nla_put_failure;
if (ctnetlink_dump_tuples(skb, nf_ct_tuple(ct, IP_CT_DIR_REPLY)) < 0)
goto nla_put_failure;
nla_nest_end(skb, nest_parms);
if (nf_ct_zone(ct)) {
if (nla_put_be16(skb, CTA_ZONE, htons(nf_ct_zone(ct))))
goto nla_put_failure;
}
if (ctnetlink_dump_id(skb, ct) < 0)
goto nla_put_failure;
if (ctnetlink_dump_status(skb, ct) < 0)
goto nla_put_failure;
if (ctnetlink_dump_timeout(skb, ct) < 0)
goto nla_put_failure;
if (ctnetlink_dump_protoinfo(skb, ct) < 0)
goto nla_put_failure;
if (ctnetlink_dump_helpinfo(skb, ct) < 0)
goto nla_put_failure;
#ifdef CONFIG_NF_CONNTRACK_SECMARK
if (ct->secmark && ctnetlink_dump_secctx(skb, ct) < 0)
goto nla_put_failure;
#endif
if (ct->master && ctnetlink_dump_master(skb, ct) < 0)
goto nla_put_failure;
if ((ct->status & IPS_SEQ_ADJUST) &&
ctnetlink_dump_nat_seq_adj(skb, ct) < 0)
goto nla_put_failure;
#ifdef CONFIG_NF_CONNTRACK_MARK
if (ct->mark && ctnetlink_dump_mark(skb, ct) < 0)
goto nla_put_failure;
#endif
rcu_read_unlock();
return 0;
nla_put_failure:
rcu_read_unlock();
return -ENOSPC;
}
static int
ctnetlink_nfqueue_parse_ct(const struct nlattr *cda[], struct nf_conn *ct)
{
int err;
if (cda[CTA_TIMEOUT]) {
err = ctnetlink_change_timeout(ct, cda);
if (err < 0)
return err;
}
if (cda[CTA_STATUS]) {
err = ctnetlink_change_status(ct, cda);
if (err < 0)
return err;
}
if (cda[CTA_HELP]) {
err = ctnetlink_change_helper(ct, cda);
if (err < 0)
return err;
}
#if defined(CONFIG_NF_CONNTRACK_MARK)
if (cda[CTA_MARK])
ct->mark = ntohl(nla_get_be32(cda[CTA_MARK]));
#endif
return 0;
}
static int
ctnetlink_nfqueue_parse(const struct nlattr *attr, struct nf_conn *ct)
{
struct nlattr *cda[CTA_MAX+1];
nla_parse_nested(cda, CTA_MAX, attr, ct_nla_policy);
return ctnetlink_nfqueue_parse_ct((const struct nlattr **)cda, ct);
}
static struct nfq_ct_hook ctnetlink_nfqueue_hook = {
.build_size = ctnetlink_nfqueue_build_size,
.build = ctnetlink_nfqueue_build,
.parse = ctnetlink_nfqueue_parse,
};
#endif /* CONFIG_NETFILTER_NETLINK_QUEUE */
/***********************************************************************
* EXPECT
***********************************************************************/
......@@ -2424,7 +2558,11 @@ static int __init ctnetlink_init(void)
pr_err("ctnetlink_init: cannot register pernet operations\n");
goto err_unreg_exp_subsys;
}
#if defined(CONFIG_NETFILTER_NETLINK_QUEUE) || \
defined(CONFIG_NETFILTER_NETLINK_QUEUE_MODULE)
/* setup interaction between nf_queue and nf_conntrack_netlink. */
RCU_INIT_POINTER(nfq_ct_hook, &ctnetlink_nfqueue_hook);
#endif
return 0;
err_unreg_exp_subsys:
......@@ -2442,6 +2580,10 @@ static void __exit ctnetlink_exit(void)
unregister_pernet_subsys(&ctnetlink_net_ops);
nfnetlink_subsys_unregister(&ctnl_exp_subsys);
nfnetlink_subsys_unregister(&ctnl_subsys);
#if defined(CONFIG_NETFILTER_NETLINK_QUEUE) || \
defined(CONFIG_NETFILTER_NETLINK_QUEUE_MODULE)
RCU_INIT_POINTER(nfq_ct_hook, NULL);
#endif
}
module_init(ctnetlink_init);
......
......@@ -30,6 +30,7 @@
#include <linux/list.h>
#include <net/sock.h>
#include <net/netfilter/nf_queue.h>
#include <net/netfilter/nf_conntrack.h>
#include <linux/atomic.h>
......@@ -233,6 +234,9 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
struct sk_buff *entskb = entry->skb;
struct net_device *indev;
struct net_device *outdev;
struct nfq_ct_hook *nfq_ct;
struct nf_conn *ct = NULL;
enum ip_conntrack_info uninitialized_var(ctinfo);
size = NLMSG_SPACE(sizeof(struct nfgenmsg))
+ nla_total_size(sizeof(struct nfqnl_msg_packet_hdr))
......@@ -266,6 +270,17 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
break;
}
/* rcu_read_lock()ed by __nf_queue already. */
nfq_ct = rcu_dereference(nfq_ct_hook);
if (nfq_ct != NULL && (queue->flags & NFQA_CFG_F_CONNTRACK)) {
ct = nf_ct_get(entskb, &ctinfo);
if (ct) {
if (!nf_ct_is_untracked(ct))
size += nfq_ct->build_size(ct);
else
ct = NULL;
}
}
skb = alloc_skb(size, GFP_ATOMIC);
if (!skb)
......@@ -389,6 +404,24 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
BUG();
}
if (ct) {
struct nlattr *nest_parms;
u_int32_t tmp;
nest_parms = nla_nest_start(skb, NFQA_CT | NLA_F_NESTED);
if (!nest_parms)
goto nla_put_failure;
if (nfq_ct->build(skb, ct) < 0)
goto nla_put_failure;
nla_nest_end(skb, nest_parms);
tmp = ctinfo;
if (nla_put_u32(skb, NFQA_CT_INFO, htonl(ctinfo)))
goto nla_put_failure;
}
nlh->nlmsg_len = skb->tail - old_tail;
return skb;
......@@ -632,6 +665,7 @@ static const struct nla_policy nfqa_verdict_policy[NFQA_MAX+1] = {
[NFQA_VERDICT_HDR] = { .len = sizeof(struct nfqnl_msg_verdict_hdr) },
[NFQA_MARK] = { .type = NLA_U32 },
[NFQA_PAYLOAD] = { .type = NLA_UNSPEC },
[NFQA_CT] = { .type = NLA_UNSPEC },
};
static const struct nla_policy nfqa_verdict_batch_policy[NFQA_MAX+1] = {
......@@ -732,6 +766,7 @@ nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
struct nfqnl_instance *queue;
unsigned int verdict;
struct nf_queue_entry *entry;
struct nfq_ct_hook *nfq_ct;
queue = instance_lookup(queue_num);
if (!queue)
......@@ -750,6 +785,19 @@ nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
if (entry == NULL)
return -ENOENT;
rcu_read_lock();
nfq_ct = rcu_dereference(nfq_ct_hook);
if (nfq_ct != NULL &&
(queue->flags & NFQA_CFG_F_CONNTRACK) && nfqa[NFQA_CT]) {
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
ct = nf_ct_get(entry->skb, &ctinfo);
if (ct && !nf_ct_is_untracked(ct))
nfq_ct->parse(nfqa[NFQA_CT], ct);
}
rcu_read_unlock();
if (nfqa[NFQA_PAYLOAD]) {
if (nfqnl_mangle(nla_data(nfqa[NFQA_PAYLOAD]),
nla_len(nfqa[NFQA_PAYLOAD]), entry) < 0)
......
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