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Message-Id: <1339524380-2707-5-git-send-email-pablo@netfilter.org>
Date: Tue, 12 Jun 2012 20:06:17 +0200
From: pablo@...filter.org
To: netfilter-devel@...r.kernel.org
Cc: netdev@...r.kernel.org
Subject: [PATCH 4/7] netfilter: add glue code to integrate nfnetlink_queue and ctnetlink
From: Pablo Neira Ayuso <pablo@...filter.org>
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: Pablo Neira Ayuso <pablo@...filter.org>
---
include/linux/netfilter.h | 10 ++
include/linux/netfilter/nfnetlink_queue.h | 3 +
net/netfilter/core.c | 4 +
net/netfilter/nf_conntrack_netlink.c | 146 ++++++++++++++++++++++++++++-
net/netfilter/nfnetlink_queue.c | 47 ++++++++++
5 files changed, 209 insertions(+), 1 deletion(-)
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 4541f33..ba65bfb 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -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
diff --git a/include/linux/netfilter/nfnetlink_queue.h b/include/linux/netfilter/nfnetlink_queue.h
index a6c1dda..e0d8fd8 100644
--- a/include/linux/netfilter/nfnetlink_queue.h
+++ b/include/linux/netfilter/nfnetlink_queue.h
@@ -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 */
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index e19f365..7eef845 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -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
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index a088920..3b03a86 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -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 +2558,12 @@ 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);
+ printk("registering nf_queue and ctnetlink interaction\n");
+#endif
return 0;
err_unreg_exp_subsys:
@@ -2442,6 +2581,11 @@ 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);
+ printk("unregistering nf_queue and ctnetlink interaction\n");
+#endif
}
module_init(ctnetlink_init);
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 630da3d..ab1fd1c 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -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;
@@ -732,6 +765,7 @@ 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 +784,19 @@ 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)
--
1.7.10
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