[iptables PATCH v5 1/2] extensions: libxt_conntrack: print xlate state as set

[iptables PATCH v5 1/2] extensions: libxt_conntrack: print xlate state as set

[Alexander Mikhalitsyn]

Currently, state_xlate_print function prints statemask as comma-separated sequence of enabled
statemask flags. But if we have inverted conntrack ctstate condition then we have to use more
complex expression because nft not supports syntax like "ct state != related,established".

Reproducer:
$ iptables -A INPUT -d 127.0.0.1/32 -p tcp -m conntrack ! --ctstate RELATED,ESTABLISHED -j DROP
$ nft list ruleset
...
meta l4proto tcp ip daddr 127.0.0.1 ct state != related,established counter packets 0 bytes 0 drop
...

it will fail if we try to load this rule:
$ nft -f nft_test
../nft_test:6:97-97: Error: syntax error, unexpected comma, expecting newline or semicolon

Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
---
 extensions/libxt_conntrack.c      | 38 +++++++++++++++++++++++++-------------
 extensions/libxt_conntrack.txlate |  5 ++++-
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/extensions/libxt_conntrack.c b/extensions/libxt_conntrack.c
index 7734509..91f9e4a 100644
--- a/extensions/libxt_conntrack.c
+++ b/extensions/libxt_conntrack.c
@@ -1148,30 +1148,43 @@ static void state_save(const void *ip, const struct xt_entry_match *match)
 	state_print_state(sinfo->statemask);
 }
 
-static void state_xlate_print(struct xt_xlate *xl, unsigned int statemask)
+static void state_xlate_print(struct xt_xlate *xl, unsigned int statemask, int inverted)
 {
 	const char *sep = "";
+	int one_flag_set;
+
+	one_flag_set = !(statemask & (statemask - 1));
+
+	if (inverted && !one_flag_set)
+		xt_xlate_add(xl, "& (");
+	else if (inverted)
+		xt_xlate_add(xl, "& ");
 
 	if (statemask & XT_CONNTRACK_STATE_INVALID) {
 		xt_xlate_add(xl, "%s%s", sep, "invalid");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statemask & XT_CONNTRACK_STATE_BIT(IP_CT_NEW)) {
 		xt_xlate_add(xl, "%s%s", sep, "new");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statemask & XT_CONNTRACK_STATE_BIT(IP_CT_RELATED)) {
 		xt_xlate_add(xl, "%s%s", sep, "related");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statemask & XT_CONNTRACK_STATE_BIT(IP_CT_ESTABLISHED)) {
 		xt_xlate_add(xl, "%s%s", sep, "established");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statemask & XT_CONNTRACK_STATE_UNTRACKED) {
 		xt_xlate_add(xl, "%s%s", sep, "untracked");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
+
+	if (inverted && !one_flag_set)
+		xt_xlate_add(xl, ") == 0");
+	else if (inverted)
+		xt_xlate_add(xl, " == 0");
 }
 
 static int state_xlate(struct xt_xlate *xl,
@@ -1180,9 +1193,9 @@ static int state_xlate(struct xt_xlate *xl,
 	const struct xt_conntrack_mtinfo3 *sinfo =
 		(const void *)params->match->data;
 
-	xt_xlate_add(xl, "ct state %s", sinfo->invert_flags & XT_CONNTRACK_STATE ?
-					"!= " : "");
-	state_xlate_print(xl, sinfo->state_mask);
+	xt_xlate_add(xl, "ct state ");
+	state_xlate_print(xl, sinfo->state_mask,
+			  sinfo->invert_flags & XT_CONNTRACK_STATE);
 	xt_xlate_add(xl, " ");
 	return 1;
 }
@@ -1256,10 +1269,9 @@ static int _conntrack3_mt_xlate(struct xt_xlate *xl,
 				     sinfo->state_mask & XT_CONNTRACK_STATE_SNAT ? "snat" : "dnat");
 			space = " ";
 		} else {
-			xt_xlate_add(xl, "%sct state %s", space,
-				     sinfo->invert_flags & XT_CONNTRACK_STATE ?
-				     "!= " : "");
-			state_xlate_print(xl, sinfo->state_mask);
+			xt_xlate_add(xl, "%sct state ", space);
+			state_xlate_print(xl, sinfo->state_mask,
+					  sinfo->invert_flags & XT_CONNTRACK_STATE);
 			space = " ";
 		}
 	}
diff --git a/extensions/libxt_conntrack.txlate b/extensions/libxt_conntrack.txlate
index d374f8a..5ab85b1 100644
--- a/extensions/libxt_conntrack.txlate
+++ b/extensions/libxt_conntrack.txlate
@@ -2,7 +2,10 @@ iptables-translate -t filter -A INPUT -m conntrack --ctstate NEW,RELATED -j ACCE
 nft add rule ip filter INPUT ct state new,related counter accept
 
 ip6tables-translate -t filter -A INPUT -m conntrack ! --ctstate NEW,RELATED -j ACCEPT
-nft add rule ip6 filter INPUT ct state != new,related counter accept
+nft add rule ip6 filter INPUT ct state & (new|related) == 0 counter accept
+
+ip6tables-translate -t filter -A INPUT -m conntrack ! --ctstate NEW -j ACCEPT
+nft add rule ip6 filter INPUT ct state & new == 0 counter accept
 
 iptables-translate -t filter -A INPUT -m conntrack --ctproto UDP -j ACCEPT
 nft add rule ip filter INPUT ct original protocol 17 counter accept
-- 
1.8.3.1

[iptables PATCH v5 2/2] extensions: libxt_conntrack: print xlate status as set

[Alexander Mikhalitsyn]

At the moment, status_xlate_print function prints statusmask as comma-separated
sequence of enabled statusmask flags. But if we have inverted conntrack ctstatus
condition then we have to use more complex expression (if more than one flag enabled)
because nft not supports syntax like "ct status != expected,assured".

Examples:
! --ctstatus CONFIRMED,ASSURED
should be translated as
ct status & (assured|confirmed) == 0

! --ctstatus CONFIRMED
can be translated as
ct status & confirmed == 0

See also netfilter/xt_conntrack.c (conntrack_mt() function as a reference).

Reproducer:
$ iptables -A INPUT -d 127.0.0.1/32 -p tcp -m conntrack ! --ctstatus expected,assured -j DROP
$ nft list ruleset
...
meta l4proto tcp ip daddr 127.0.0.1 ct status != expected,assured counter packets 0 bytes 0 drop
...

it will fail if we try to load this rule:
$ nft -f nft_test
../nft_test:6:97-97: Error: syntax error, unexpected comma, expecting newline or semicolon

Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
---
 extensions/libxt_conntrack.c      | 30 +++++++++++++++++++++---------
 extensions/libxt_conntrack.txlate |  8 +++++++-
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/extensions/libxt_conntrack.c b/extensions/libxt_conntrack.c
index 91f9e4a..7f7b45e 100644
--- a/extensions/libxt_conntrack.c
+++ b/extensions/libxt_conntrack.c
@@ -1200,26 +1200,39 @@ static int state_xlate(struct xt_xlate *xl,
 	return 1;
 }
 
-static void status_xlate_print(struct xt_xlate *xl, unsigned int statusmask)
+static void status_xlate_print(struct xt_xlate *xl, unsigned int statusmask, int inverted)
 {
 	const char *sep = "";
+	int one_flag_set;
+
+	one_flag_set = !(statusmask & (statusmask - 1));
+
+	if (inverted && !one_flag_set)
+		xt_xlate_add(xl, "& (");
+	else if (inverted)
+		xt_xlate_add(xl, "& ");
 
 	if (statusmask & IPS_EXPECTED) {
 		xt_xlate_add(xl, "%s%s", sep, "expected");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statusmask & IPS_SEEN_REPLY) {
 		xt_xlate_add(xl, "%s%s", sep, "seen-reply");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statusmask & IPS_ASSURED) {
 		xt_xlate_add(xl, "%s%s", sep, "assured");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statusmask & IPS_CONFIRMED) {
 		xt_xlate_add(xl, "%s%s", sep, "confirmed");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
+
+	if (inverted && !one_flag_set)
+		xt_xlate_add(xl, ") == 0");
+	else if (inverted)
+		xt_xlate_add(xl, " == 0");
 }
 
 static void addr_xlate_print(struct xt_xlate *xl,
@@ -1277,10 +1290,9 @@ static int _conntrack3_mt_xlate(struct xt_xlate *xl,
 	}
 
 	if (sinfo->match_flags & XT_CONNTRACK_STATUS) {
-		xt_xlate_add(xl, "%sct status %s", space,
-			     sinfo->invert_flags & XT_CONNTRACK_STATUS ?
-			     "!= " : "");
-		status_xlate_print(xl, sinfo->status_mask);
+		xt_xlate_add(xl, "%sct status ", space);
+		status_xlate_print(xl, sinfo->status_mask,
+				   sinfo->invert_flags & XT_CONNTRACK_STATUS);
 		space = " ";
 	}
 
diff --git a/extensions/libxt_conntrack.txlate b/extensions/libxt_conntrack.txlate
index 5ab85b1..8cc7c50 100644
--- a/extensions/libxt_conntrack.txlate
+++ b/extensions/libxt_conntrack.txlate
@@ -35,7 +35,13 @@ iptables-translate -t filter -A INPUT -m conntrack --ctstatus EXPECTED -j ACCEPT
 nft add rule ip filter INPUT ct status expected counter accept
 
 iptables-translate -t filter -A INPUT -m conntrack ! --ctstatus CONFIRMED -j ACCEPT
-nft add rule ip filter INPUT ct status != confirmed counter accept
+nft add rule ip filter INPUT ct status & confirmed == 0 counter accept
+
+iptables-translate -t filter -A INPUT -m conntrack ! --ctstatus CONFIRMED,ASSURED -j ACCEPT
+nft add rule ip filter INPUT ct status & (assured|confirmed) == 0 counter accept
+
+iptables-translate -t filter -A INPUT -m conntrack --ctstatus CONFIRMED,ASSURED -j ACCEPT
+nft add rule ip filter INPUT ct status assured,confirmed counter accept
 
 iptables-translate -t filter -A INPUT -m conntrack --ctexpire 3 -j ACCEPT
 nft add rule ip filter INPUT ct expiration 3 counter accept
-- 
1.8.3.1

Re: [iptables PATCH v5 1/2] extensions: libxt_conntrack: print xlate state as set

[Florian Westphal]

Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> wrote:
> Currently, state_xlate_print function prints statemask as comma-separated sequence of enabled
> statemask flags. But if we have inverted conntrack ctstate condition then we have to use more
> complex expression because nft not supports syntax like "ct state != related,established".

Applied, thanks.

Re: [iptables PATCH v5 2/2] extensions: libxt_conntrack: print xlate status as set

[Florian Westphal]

Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> wrote:
> At the moment, status_xlate_print function prints statusmask as comma-separated
> sequence of enabled statusmask flags. But if we have inverted conntrack ctstatus
> condition then we have to use more complex expression (if more than one flag enabled)
> because nft not supports syntax like "ct status != expected,assured".

Also applied.

Re: [iptables PATCH v5 2/2] extensions: libxt_conntrack: print xlate status as set

[Alexander Mikhalitsyn]

On Fri, 2 Apr 2021 17:08:35 +0200
Florian Westphal <fw@strlen.de> wrote:

> Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> wrote:
> > At the moment, status_xlate_print function prints statusmask as comma-separated
> > sequence of enabled statusmask flags. But if we have inverted conntrack ctstatus
> > condition then we have to use more complex expression (if more than one flag enabled)
> > because nft not supports syntax like "ct status != expected,assured".
> 
> Also applied.

Thank you for your help and review!

Regards,
Alex