netfilter: nftables: ctnetlink event type set support

netfilter: nftables: ctnetlink event type set support

[Florian Westphal]

nftables equivalent for -j CT --ctevents.

Unlike iptables this doesn't work with conntrack templates,
it must be used with the real conntrack objects instead (i.e.,
after conntrack picked the packet up for processing).

patch #1 is for kernel, 2 and 3 for libnftnl/nftables userland.

[PATCH nf-next 1/3] netfilter: nft_ct: allow to set ctnetlink event types of a connection

[Florian Westphal]

by default the kernel emits all ctnetlink events for a connection.
This allows to select the types of events to generate for a connection.

This allows to e.g. only send DESTROY events but no NEW/UPDATE ones.

This was already possible via iptables' CT target.
The nft version has the advantage that it can also be used with
already-established conntracks.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/uapi/linux/netfilter/nf_tables.h |  2 ++
 net/netfilter/nft_ct.c                   | 19 ++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 8f3842690d17..683f6f88fcac 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -901,6 +901,7 @@ enum nft_rt_attributes {
  * @NFT_CT_BYTES: conntrack bytes
  * @NFT_CT_AVGPKT: conntrack average bytes per packet
  * @NFT_CT_ZONE: conntrack zone
+ * @NFT_CT_EVENTMASK: ctnetlink events to be generated for this conntrack
  */
 enum nft_ct_keys {
 	NFT_CT_STATE,
@@ -921,6 +922,7 @@ enum nft_ct_keys {
 	NFT_CT_BYTES,
 	NFT_CT_AVGPKT,
 	NFT_CT_ZONE,
+	NFT_CT_EVENTMASK,
 };
 
 /**
diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 6e23dbbedd7f..4f642977f8a5 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -264,7 +264,7 @@ static void nft_ct_set_eval(const struct nft_expr *expr,
 	struct nf_conn *ct;
 
 	ct = nf_ct_get(skb, &ctinfo);
-	if (ct == NULL)
+	if (ct == NULL || nf_ct_is_template(ct))
 		return;
 
 	switch (priv->key) {
@@ -284,6 +284,16 @@ static void nft_ct_set_eval(const struct nft_expr *expr,
 				      NF_CT_LABELS_MAX_SIZE / sizeof(u32));
 		break;
 #endif
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+	case NFT_CT_EVENTMASK: {
+		struct nf_conntrack_ecache *e = nf_ct_ecache_find(ct);
+		u16 ctmask = (u16)regs->data[priv->sreg];
+
+		if (e && e->ctmask != ctmask)
+			e->ctmask = ctmask;
+		break;
+	}
+#endif
 	default:
 		break;
 	}
@@ -539,6 +549,13 @@ static int nft_ct_set_init(const struct nft_ctx *ctx,
 		len = sizeof(u16);
 		break;
 #endif
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+	case NFT_CT_EVENTMASK:
+		if (tb[NFTA_CT_DIRECTION])
+			return -EINVAL;
+		len = sizeof(u32);
+		break;
+#endif
 	default:
 		return -EOPNOTSUPP;
 	}
-- 
2.10.2

Re: [PATCH nf-next 1/3] netfilter: nft_ct: allow to set ctnetlink event types of a connection

[Pablo Neira Ayuso]

On Sat, Apr 15, 2017 at 10:45:03AM +0200, Florian Westphal wrote:
> by default the kernel emits all ctnetlink events for a connection.
> This allows to select the types of events to generate for a connection.
> 
> This allows to e.g. only send DESTROY events but no NEW/UPDATE ones.
> 
> This was already possible via iptables' CT target.
> The nft version has the advantage that it can also be used with
> already-established conntracks.
> 
> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
>  include/uapi/linux/netfilter/nf_tables.h |  2 ++
>  net/netfilter/nft_ct.c                   | 19 ++++++++++++++++++-
>  2 files changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
> index 8f3842690d17..683f6f88fcac 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -901,6 +901,7 @@ enum nft_rt_attributes {
>   * @NFT_CT_BYTES: conntrack bytes
>   * @NFT_CT_AVGPKT: conntrack average bytes per packet
>   * @NFT_CT_ZONE: conntrack zone
> + * @NFT_CT_EVENTMASK: ctnetlink events to be generated for this conntrack
>   */
>  enum nft_ct_keys {
>  	NFT_CT_STATE,
> @@ -921,6 +922,7 @@ enum nft_ct_keys {
>  	NFT_CT_BYTES,
>  	NFT_CT_AVGPKT,
>  	NFT_CT_ZONE,
> +	NFT_CT_EVENTMASK,
>  };
>  
>  /**
> diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
> index 6e23dbbedd7f..4f642977f8a5 100644
> --- a/net/netfilter/nft_ct.c
> +++ b/net/netfilter/nft_ct.c
> @@ -264,7 +264,7 @@ static void nft_ct_set_eval(const struct nft_expr *expr,
>  	struct nf_conn *ct;
>  
>  	ct = nf_ct_get(skb, &ctinfo);
> -	if (ct == NULL)
> +	if (ct == NULL || nf_ct_is_template(ct))

I wonder if this should go in a oneliner, given this is fixing the
fact that we may end up using the template. So someone has a chance to
pass it to -stable. I'll be fine either way, no problem.

Another comment below.

>  		return;
>  
>  	switch (priv->key) {
> @@ -284,6 +284,16 @@ static void nft_ct_set_eval(const struct nft_expr *expr,
>  				      NF_CT_LABELS_MAX_SIZE / sizeof(u32));
>  		break;
>  #endif
> +#ifdef CONFIG_NF_CONNTRACK_EVENTS
> +	case NFT_CT_EVENTMASK: {
> +		struct nf_conntrack_ecache *e = nf_ct_ecache_find(ct);
> +		u16 ctmask = (u16)regs->data[priv->sreg];

Liping added helpers to fetch data from registers, I think it
applies to this case too.

Thanks!

Re: [PATCH nf-next 1/3] netfilter: nft_ct: allow to set ctnetlink event types of a connection

[Florian Westphal]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> I wonder if this should go in a oneliner, given this is fixing the
> fact that we may end up using the template. So someone has a chance to
> pass it to -stable. I'll be fine either way, no problem.

Ok. will do.

> > +#ifdef CONFIG_NF_CONNTRACK_EVENTS
> > +	case NFT_CT_EVENTMASK: {
> > +		struct nf_conntrack_ecache *e = nf_ct_ecache_find(ct);
> > +		u16 ctmask = (u16)regs->data[priv->sreg];
> 
> Liping added helpers to fetch data from registers, I think it
> applies to this case too.

Right, I forgot about this, thanks for noticing.
Having such huge backlog is crap, I won't do this again, ever :(

Re: [PATCH nf-next 1/3] netfilter: nft_ct: allow to set ctnetlink event types of a connection

[Pablo Neira Ayuso]

On Sat, Apr 15, 2017 at 11:44:39AM +0200, Florian Westphal wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > I wonder if this should go in a oneliner, given this is fixing the
> > fact that we may end up using the template. So someone has a chance to
> > pass it to -stable. I'll be fine either way, no problem.
> 
> Ok. will do.

Thanks Florian.

> > > +#ifdef CONFIG_NF_CONNTRACK_EVENTS
> > > +	case NFT_CT_EVENTMASK: {
> > > +		struct nf_conntrack_ecache *e = nf_ct_ecache_find(ct);
> > > +		u16 ctmask = (u16)regs->data[priv->sreg];
> > 
> > Liping added helpers to fetch data from registers, I think it
> > applies to this case too.
> 
> Right, I forgot about this, thanks for noticing.
> Having such huge backlog is crap, I won't do this again, ever :(

I tend to repeat this to myself... but sometimes it doesn't seem to
work ;)

[PATCH libnftnl 2/3] src: ct eventmask support

[Florian Westphal]

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/linux/netfilter/nf_tables.h | 2 ++
 src/expr/ct.c                       | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index 8f3842690d17..683f6f88fcac 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -901,6 +901,7 @@ enum nft_rt_attributes {
  * @NFT_CT_BYTES: conntrack bytes
  * @NFT_CT_AVGPKT: conntrack average bytes per packet
  * @NFT_CT_ZONE: conntrack zone
+ * @NFT_CT_EVENTMASK: ctnetlink events to be generated for this conntrack
  */
 enum nft_ct_keys {
 	NFT_CT_STATE,
@@ -921,6 +922,7 @@ enum nft_ct_keys {
 	NFT_CT_BYTES,
 	NFT_CT_AVGPKT,
 	NFT_CT_ZONE,
+	NFT_CT_EVENTMASK,
 };
 
 /**
diff --git a/src/expr/ct.c b/src/expr/ct.c
index cdd08e95c86c..0fba0d668010 100644
--- a/src/expr/ct.c
+++ b/src/expr/ct.c
@@ -32,7 +32,7 @@ struct nftnl_expr_ct {
 #define IP_CT_DIR_REPLY		1
 
 #ifndef NFT_CT_MAX
-#define NFT_CT_MAX (NFT_CT_ZONE + 1)
+#define NFT_CT_MAX (NFT_CT_EVENTMASK + 1)
 #endif
 
 static int
@@ -171,6 +171,7 @@ static const char *ctkey2str_array[NFT_CT_MAX] = {
 	[NFT_CT_BYTES]		= "bytes",
 	[NFT_CT_AVGPKT]		= "avgpkt",
 	[NFT_CT_ZONE]		= "zone",
+	[NFT_CT_EVENTMASK]	= "eventmask",
 };
 
 static const char *ctkey2str(uint32_t ctkey)
-- 
2.10.2

[PATCH nft 3/3] ct: add conntrack event mask support

[Florian Westphal]

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 doc/nft.xml                                   | 15 +++++
 include/datatype.h                            |  1 +
 include/linux/netfilter/nf_conntrack_common.h | 80 ++++++---------------------
 include/linux/netfilter/nf_tables.h           |  2 +
 src/ct.c                                      | 30 ++++++++++
 tests/py/any/ct.t                             |  6 ++
 tests/py/any/ct.t.payload                     | 20 +++++++
 7 files changed, 90 insertions(+), 64 deletions(-)

diff --git a/doc/nft.xml b/doc/nft.xml
index 57cf5cf11352..4d0e89cd2054 100644
--- a/doc/nft.xml
+++ b/doc/nft.xml
@@ -3864,6 +3864,7 @@ ip6 filter output log flags all
 					<command>ct</command>
 					<group choice="req">
 						<arg>mark</arg>
+						<arg>eventmask</arg>
 						<arg>label</arg>
 						<arg>zone</arg>
 					</group>
@@ -3894,6 +3895,12 @@ ip6 filter output log flags all
 						</thead>
 						<tbody>
 							<row>
+								<entry>eventmask</entry>
+								<entry>conntrack event bits</entry>
+								<entry>bitmask, integer (32 bit)</entry>
+							</row>
+
+							<row>
 								<entry>helper</entry>
 								<entry>name of ct helper object to assign to the connection</entry>
 								<entry>quoted string</entry>
@@ -3940,6 +3947,14 @@ table inet raw {
 }
 				</programlisting>
 			</example>
+			<example>
+					<title>restrict events reported by ctnetlink</title>
+				<programlisting>
+ct eventmask set new or related or destroy
+				</programlisting>
+			</example>
+
+
 			</para>
 		</refsect2>
 		<refsect2>
diff --git a/include/datatype.h b/include/datatype.h
index e614b96e880b..04b7d8808cea 100644
--- a/include/datatype.h
+++ b/include/datatype.h
@@ -83,6 +83,7 @@ enum datatypes {
 	TYPE_ECN,
 	TYPE_FIB_ADDR,
 	TYPE_BOOLEAN,
+	TYPE_CT_EVENTBIT,
 	__TYPE_MAX
 };
 #define TYPE_MAX		(__TYPE_MAX - 1)
diff --git a/include/linux/netfilter/nf_conntrack_common.h b/include/linux/netfilter/nf_conntrack_common.h
index 27a1895218db..768ff251308b 100644
--- a/include/linux/netfilter/nf_conntrack_common.h
+++ b/include/linux/netfilter/nf_conntrack_common.h
@@ -79,73 +79,25 @@ enum ip_conntrack_status {
 	IPS_FIXED_TIMEOUT = (1 << IPS_FIXED_TIMEOUT_BIT),
 };
 
-/* Connection tracking event bits */
-enum ip_conntrack_events
-{
-	/* New conntrack */
-	IPCT_NEW_BIT = 0,
-	IPCT_NEW = (1 << IPCT_NEW_BIT),
-
-	/* Expected connection */
-	IPCT_RELATED_BIT = 1,
-	IPCT_RELATED = (1 << IPCT_RELATED_BIT),
-
-	/* Destroyed conntrack */
-	IPCT_DESTROY_BIT = 2,
-	IPCT_DESTROY = (1 << IPCT_DESTROY_BIT),
-
-	/* Timer has been refreshed */
-	IPCT_REFRESH_BIT = 3,
-	IPCT_REFRESH = (1 << IPCT_REFRESH_BIT),
-
-	/* Status has changed */
-	IPCT_STATUS_BIT = 4,
-	IPCT_STATUS = (1 << IPCT_STATUS_BIT),
-
-	/* Update of protocol info */
-	IPCT_PROTOINFO_BIT = 5,
-	IPCT_PROTOINFO = (1 << IPCT_PROTOINFO_BIT),
-
-	/* Volatile protocol info */
-	IPCT_PROTOINFO_VOLATILE_BIT = 6,
-	IPCT_PROTOINFO_VOLATILE = (1 << IPCT_PROTOINFO_VOLATILE_BIT),
-
-	/* New helper for conntrack */
-	IPCT_HELPER_BIT = 7,
-	IPCT_HELPER = (1 << IPCT_HELPER_BIT),
-
-	/* Update of helper info */
-	IPCT_HELPINFO_BIT = 8,
-	IPCT_HELPINFO = (1 << IPCT_HELPINFO_BIT),
-
-	/* Volatile helper info */
-	IPCT_HELPINFO_VOLATILE_BIT = 9,
-	IPCT_HELPINFO_VOLATILE = (1 << IPCT_HELPINFO_VOLATILE_BIT),
-
-	/* NAT info */
-	IPCT_NATINFO_BIT = 10,
-	IPCT_NATINFO = (1 << IPCT_NATINFO_BIT),
-
-	/* Counter highest bit has been set, unused */
-	IPCT_COUNTER_FILLING_BIT = 11,
-	IPCT_COUNTER_FILLING = (1 << IPCT_COUNTER_FILLING_BIT),
-
-	/* Mark is set */
-	IPCT_MARK_BIT = 12,
-	IPCT_MARK = (1 << IPCT_MARK_BIT),
-
-	/* NAT sequence adjustment */
-	IPCT_NATSEQADJ_BIT = 13,
-	IPCT_NATSEQADJ = (1 << IPCT_NATSEQADJ_BIT),
-
-	/* Secmark is set */
-	IPCT_SECMARK_BIT = 14,
-	IPCT_SECMARK = (1 << IPCT_SECMARK_BIT),
+/* Connection tracking event types */
+enum ip_conntrack_events {
+	IPCT_NEW,		/* new conntrack */
+	IPCT_RELATED,		/* related conntrack */
+	IPCT_DESTROY,		/* destroyed conntrack */
+	IPCT_REPLY,		/* connection has seen two-way traffic */
+	IPCT_ASSURED,		/* connection status has changed to assured */
+	IPCT_PROTOINFO,		/* protocol information has changed */
+	IPCT_HELPER,		/* new helper has been set */
+	IPCT_MARK,		/* new mark has been set */
+	IPCT_SEQADJ,		/* sequence adjustment has changed */
+	IPCT_NATSEQADJ = IPCT_SEQADJ,
+	IPCT_SECMARK,		/* new security mark has been set */
+	IPCT_LABEL,		/* new connlabel has been set */
 };
 
 enum ip_conntrack_expect_events {
-	IPEXP_NEW_BIT = 0,
-	IPEXP_NEW = (1 << IPEXP_NEW_BIT),
+	IPEXP_NEW,		/* new expectation */
+	IPEXP_DESTROY,		/* destroyed expectation */
 };
 
 
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index 8f3842690d17..683f6f88fcac 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -901,6 +901,7 @@ enum nft_rt_attributes {
  * @NFT_CT_BYTES: conntrack bytes
  * @NFT_CT_AVGPKT: conntrack average bytes per packet
  * @NFT_CT_ZONE: conntrack zone
+ * @NFT_CT_EVENTMASK: ctnetlink events to be generated for this conntrack
  */
 enum nft_ct_keys {
 	NFT_CT_STATE,
@@ -921,6 +922,7 @@ enum nft_ct_keys {
 	NFT_CT_BYTES,
 	NFT_CT_AVGPKT,
 	NFT_CT_ZONE,
+	NFT_CT_EVENTMASK,
 };
 
 /**
diff --git a/src/ct.c b/src/ct.c
index fd8ca87a21fb..5014265a3427 100644
--- a/src/ct.c
+++ b/src/ct.c
@@ -100,6 +100,34 @@ static const struct datatype ct_status_type = {
 	.sym_tbl	= &ct_status_tbl,
 };
 
+static const struct symbol_table ct_events_tbl = {
+	.base		= BASE_HEXADECIMAL,
+	.symbols	= {
+		SYMBOL("new",		1 << IPCT_NEW),
+		SYMBOL("related",	1 << IPCT_RELATED),
+		SYMBOL("destroy",	1 << IPCT_DESTROY),
+		SYMBOL("reply",		1 << IPCT_REPLY),
+		SYMBOL("assured",	1 << IPCT_ASSURED),
+		SYMBOL("protoinfo",	1 << IPCT_PROTOINFO),
+		SYMBOL("helper",	1 << IPCT_HELPER),
+		SYMBOL("mark",		1 << IPCT_MARK),
+		SYMBOL("seqadj",	1 << IPCT_SEQADJ),
+		SYMBOL("secmark",	1 << IPCT_SECMARK),
+		SYMBOL("label",		1 << IPCT_LABEL),
+		SYMBOL_LIST_END
+	},
+};
+
+static const struct datatype ct_event_type = {
+	.type		= TYPE_CT_EVENTBIT,
+	.name		= "ct_event",
+	.desc		= "conntrack event bits",
+	.byteorder	= BYTEORDER_HOST_ENDIAN,
+	.size		= 4 * BITS_PER_BYTE,
+	.basetype	= &bitmask_type,
+	.sym_tbl	= &ct_events_tbl,
+};
+
 static struct symbol_table *ct_label_tbl;
 
 #define CT_LABEL_BIT_SIZE 128
@@ -236,6 +264,8 @@ static const struct ct_template ct_templates[] = {
 					      BYTEORDER_HOST_ENDIAN, 64),
 	[NFT_CT_ZONE]		= CT_TEMPLATE("zone", &integer_type,
 					      BYTEORDER_HOST_ENDIAN, 16),
+	[NFT_CT_EVENTMASK]	= CT_TEMPLATE("eventmask", &ct_event_type,
+					      BYTEORDER_HOST_ENDIAN, 32),
 };
 
 static void ct_print(enum nft_ct_keys key, int8_t dir)
diff --git a/tests/py/any/ct.t b/tests/py/any/ct.t
index 6f32d29c0c40..96a80f84a218 100644
--- a/tests/py/any/ct.t
+++ b/tests/py/any/ct.t
@@ -96,6 +96,12 @@ ct original mark 42;fail
 # swapped key and direction
 ct mark original;fail
 
+ct eventmask set new;ok
+ct eventmask set new or related or destroy or foobar;fail
+ct eventmask set 'new | related | destroy | label';ok;ct eventmask set new | related | destroy | label
+ct eventmask set 1;ok;ct eventmask set new
+ct eventmask set 0x0;ok
+
 ct label 127;ok
 ct label set 127;ok
 ct label 128;fail
diff --git a/tests/py/any/ct.t.payload b/tests/py/any/ct.t.payload
index e4c7f62b69f5..6077e5da63b8 100644
--- a/tests/py/any/ct.t.payload
+++ b/tests/py/any/ct.t.payload
@@ -391,6 +391,26 @@ ip test-ip4 output
   [ bitwise reg 1 = (reg=1 & 0x00000020 ) ^ 0x00000000 ]
   [ cmp neq reg 1 0x00000000 ]
 
+# ct eventmask set new
+ip test-ip4 output
+  [ immediate reg 1 0x00000001 ]
+  [ ct set eventmask with reg 1 ]
+
+# ct eventmask set 'new | related | destroy | label'
+ip test-ip4 output
+  [ immediate reg 1 0x00000407 ]
+  [ ct set eventmask with reg 1 ]
+
+# ct eventmask set 1
+ip test-ip4 output
+  [ immediate reg 1 0x00000001 ]
+  [ ct set eventmask with reg 1 ]
+
+# ct eventmask set 0x0
+ip test-ip4 output
+  [ immediate reg 1 0x00000000 ]
+  [ ct set eventmask with reg 1 ]
+
 # ct label 127
 ip test-ip4 output
   [ ct load label => reg 1 ]
-- 
2.10.2